JP7691171B2 - Embolism Retrieval Catheter - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. Patent Application No. 16/589,563, filed October 1, 2019, and also claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63/026,898, filed May 19, 2020, each of which is incorporated by reference in its entirety. Additionally, International Patent Application No. PCT/US2019/029709, filed April 29, 2019, is incorporated by reference herein.

Stroke is the third leading cause of death and the most disabling neurological disorder in the United States. Approximately 700,000 patients suffer from stroke annually. Stroke is a syndrome characterized by the acute onset of neurological deficit lasting at least 24 hours, reflects focal involvement of the central nervous system, and is the result of disturbances in cerebral circulation. Its incidence increases with age. Risk factors for stroke include systolic or diastolic hypertension, hypercholesterolemia, smoking, heavy alcohol consumption, and use of oral contraceptives.

Hemorrhagic strokes account for 20% of the annual stroke population. Hemorrhagic strokes are often caused by ruptured aneurysms or arteriovenous malformations that bleed into brain tissue resulting in cerebral infarction. The remaining 80% of the stroke population are ischemic strokes, which are caused by blocked blood vessels that deprive the brain of oxygen-bearing blood. Ischemic strokes are often caused by emboli or thrombotic tissue debris breaking off from other sites or from the cerebral vessels themselves, occluding narrower brain arteries further distally. When patients present with neurological symptoms and signs that resolve completely within an hour, the term transient ischemic attack (TIA) is used. Etiologically, TIA and stroke share the same pathophysiological mechanisms and therefore represent a continuum based on the persistence of symptoms and the extent of ischemic damage.

Emboli can form around the valves of the heart or within the left atrial appendage during irregular heart rates and then break off and follow the bloodstream to distal regions of the body. These emboli can travel to the brain and cause an embolic stroke. As discussed below, many such blockages occur in the middle cerebral artery (MCA), although this is not the only site of emboli retention.

When a patient presents with neurologic deficits, a diagnostic hypothesis regarding the cause of the stroke can be made based on the patient's medical history, review of stroke risk factors, and neurologic examination. If an ischemic event is suspected, the clinician can tentatively evaluate whether the patient has a cardiogenic embolic cause, extracranial or intracranial disease of the aorta, intraparenchymal disease of small arteries, or hematologic or other systemic disease. A head CT scan is often performed to determine whether the patient has suffered an ischemic or hemorrhagic injury. In subarachnoid hemorrhage, intraparenchymal hematoma, or intraventricular hemorrhage, blood may be present on the CT scan.

Traditionally, emergency management of acute ischemic stroke has consisted primarily of general supportive care, e.g., hydration, neurological status monitoring, blood pressure control, and/or antiplatelet or anticoagulant therapy. In 1996, the Food and Drug Administration approved the use of Genentech Inc's thrombolytic agent, tissue plasminogen activator (t-PA), or Activase®, for the treatment of acute stroke. The National Institute of Neurological Disorders and t-PA Stroke Study, a randomized, double-blind trial, demonstrated a statistically significant improvement in 24-hour Stroke Severity Rating Scale scores in the group of patients who received intravenous t-PA within 3 hours of the onset of ischemic stroke. Since the approval of t-PA, emergency room physicians are now, for the first time, able to offer stroke patients effective treatment beyond supportive care.

However, treatment with systemic t-PA is associated with an increased risk of intracerebral hemorrhage and other hemorrhagic complications. Patients treated with t-PA were more likely to sustain symptomatic intracerebral hemorrhage during the first 36 hours of treatment. The frequency of symptomatic intracerebral hemorrhage increases when t-PA is administered more than 3 hours after stroke onset. Besides the time constraints on the use of t-PA in acute ischemic stroke, other contraindications include: the patient has had a previous stroke or severe head trauma in the past 3 months, the patient has a systolic blood pressure of 185 mmHg or higher or a diastolic blood pressure of 110 mmHg or higher, the patient requires aggressive treatment to lower the blood pressure to a prescribed limit, the patient is taking anticoagulants or has a bleeding tendency, and/or the patient has recently undergone an invasive surgical procedure. Therefore, only a small percentage of selected stroke patients are eligible to receive t-PA.

Also, occlusive emboli have been mechanically removed from various sites in the vasculature for many years. Mechanical therapy includes clot capture and removal, clot lysis, clot disruption and aspiration, and/or creation of a flow pathway through the clot. One of the first mechanical devices developed for stroke treatment was the MERCI Retriever System (Concentric Medical, Redwood City, CA). A balloon-tipped guide catheter is used to access the internal carotid artery (ICA) from the femoral artery. A microcatheter is placed through the guide catheter and used to deliver a coil-tipped retriever across the clot, which is then retracted to place the retriever around the clot. The balloon is then inflated and a syringe is connected to the balloon guide catheter to aspirate the guide catheter during clot retrieval while the microcatheter and retriever are pulled back into the balloon guide catheter to finally extract the clot. This device initially showed good results compared to thrombolytic therapy alone.

Other thrombectomy devices utilize expandable frameworks, baskets, or snares to capture and retrieve the clot. Temporary stents, sometimes called stentrivers or reperfusion devices, are used to restore vascular flow as well as remove or retrieve the clot. A range of devices that use active laser or ultrasonic energy to disrupt the clot have also been used. Other active energy devices have been used in conjunction with intra-arterial thrombolytic injection to promote clot dissolution. Many of these devices have been used in conjunction with suction to aid in clot removal and reduce the risk of embolism. Clot aspiration has also been used with single lumen catheters and syringes or suction pumps, with or without clot disruption. Devices that apply a driven fluid vortex in combination with suction have been used to improve the effectiveness of this thrombectomy procedure. Finally, when removal or dissolution of the clot has not been possible, a patent lumen through the clot has been created using a balloon or stent.

Notwithstanding the foregoing, there remains a need for novel devices and methods for treating embolism in the body's vasculature, including acute ischemic stroke and embolic cerebrovascular disease.

In accordance with one aspect of the present invention, a system for removing embolic material from an intravascular site is provided. The system includes an elongated flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. An axial restraining device is carried by the sidewall and exposed to the lumen. A rotatable core wire is extendable through the lumen, the core wire having a proximal end and a distal end. A restraining device is carried by the core wire, the restraining device having a bearing surface that rotatably engages the restraining device, and a clot gripping tip is provided at the distal end of the core wire. The restraining device and the restraining device are configured to permit rotation of the core wire but limit distal advancement of the tip to no more than about 6 mm beyond the distal end of the tubular body.

The limiting and restraining devices may be configured to permit rotation of the core wire but limit distal advancement of the tip to no more than about 3 mm beyond the distal end of the tubular body. The clot gripping tip may include a helical thread form. The limiting and restraining devices may be configured to permit rotation of the core wire but limit distal advancement of the tip to exposure of between about 1 and 3 full turns of the thread form beyond the distal end of the tubular body.

The axial restraint device may include a proximally facing bearing surface. The axial restraint device may include a radially inwardly extending protrusion. The axial restraint device may include an annular flange. The limiting device may include a distally facing bearing surface. The limiting device may include a radially outwardly extending protrusion. The radially outwardly extending protrusion may be configured to be in sliding contact with the restraining device.

The proximal bearing surface of the axial restraint device may be within about 30 cm of the distal end of the tubular body. The proximal bearing surface of the axial restraint device may be within about 4 cm to about 12 cm of the distal end of the tubular body. The restraint device may be positioned within about the most distal 25% of the core wire length.

The helical thread form may have a maximum outer diameter that is no greater than about 90% of the inner diameter of the lumen, leaving an annular flow passage between the tip and the inner surface of the sidewall. The helical thread form may have a blunt outer edge.

The core wire may be removably positionable within the tubular body. The system may further include a handle configured to manually rotate the core wire.

The helical thread form may extend through no more than about 8 full revolutions. The helical thread form may have an outer diameter that increases proximally from a first diameter near the distal tip to a second maximum outer diameter, and then decreases proximally from the maximum outer diameter to a third diameter. The inner diameter of the tubular body adjacent the clot-grasping tip may be at least about 0.015 inches greater than the maximum outer diameter at the tip.

In accordance with one aspect of the present invention, a torque transmission system for rotationally orienting a distal end of a catheter is provided. The system includes an elongated flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. A first engagement surface is carried by the sidewall and exposed to the lumen. A torque wire is extendable through the lumen, the torque wire having a proximal end and a distal end. A second engagement surface is carried by the torque wire. Distal advancement of the torque wire brings the second engagement surface into rotational coupling engagement with the first engagement surface such that rotation of the torque wire in at least a first direction causes rotation of the distal end of the catheter.

The first engagement surface may include at least one angled surface and may be carried by a radially inwardly extending protrusion. The protrusion may include a ring positioned within the lumen. The second engagement surface may include a distally facing surface, which may be angled relative to the longitudinal axis of the catheter.

In accordance with another aspect of the present invention, a system for removing embolic material from an intravascular site is provided. The system includes an elongated flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. A first engagement surface is carried by the sidewall and exposed to the lumen. A tap wire is extendable through the lumen, the tap wire having a proximal end and a distal end. A second engagement surface is carried by the tap wire. Distal advancement of the tap wire causes the second engagement surface to contact the first engagement surface and transfer momentum from the tap wire to the distal end of the tubular body.

The first engagement surface may include a proximally facing surface and may be carried by a radially inwardly extending protrusion. The first engagement surface may include an annular flange. The second engagement surface may include a distally facing surface and may be carried by a distal end of a tap wire. The distally facing surface may be on a hammer head carried by the wire.

In accordance with a further aspect of the present invention, a torque transmission system for rotationally orienting a distal end of a catheter is provided. The system includes an elongated flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough. A first connector is provided on the sidewall and exposed to the lumen. A torque wire is extendable through the lumen, the torque wire having a proximal end and a distal end. A second, complementary connector is carried by the torque wire. Coupling the first and second connectors permits rotation of the distal end of the catheter in response to rotation of the torque wire.

The first connector may include at least one beveled tooth, i.e., a radially inwardly extending protrusion. The protrusion may include a ring positioned within the lumen. The ring may include at least two proximally extending teeth with beveled angles. The second connector may include a distally facing surface carried by the torque wire. The distally facing surface may include at least one beveled surface. The second connector may be radially outwardly movable and may include an inflatable balloon, and the first connector may include an inner surface on a sidewall. The first connector may include an axially extending slotted sidewall configured to receive the protrusion on the torque wire.

Also provided is a method of rotationally orienting a catheter. The method includes advancing a catheter to a site within a body cavity, the catheter having a central lumen and a distal end. A torque wire is advanced into the lumen. A first connector on the torque wire engages a second connector on the catheter to rotate the torque wire, thereby rotating the distal end of the catheter.

Any feature, structure, or step disclosed herein may be substituted, combined, or omitted with any other feature, structure, or step disclosed herein. Moreover, certain aspects, advantages, and features of the embodiments have been described herein for purposes of summarizing the disclosure. It will be understood that not each and every such advantage may be achieved in accordance with any particular embodiment disclosed herein. No individual aspect of the disclosure is essential or required. Additional features and advantages of the embodiments will become apparent to those skilled in the art in view of the following Detailed Description of the Invention when considered in conjunction with the accompanying drawings and claims.

FIG. 1A is a side elevational view of a catheter having an internal stop ring. FIG. 1B is a longitudinal cross-section through the catheter of FIG. 1A, showing a detailed view of the stop ring. FIG. 1C is a side elevational view of a stirrer having a complementary restrictor that engages the stop ring of FIGS. 1A and 1B. FIG. 1D is a side elevational view of the distal portion of the agitator body of FIG. 24C. FIG. 1E is a longitudinal section through the stirrer of FIG. 1D. 1F is a cutaway perspective view of a distal portion of the agitator of FIG. 24C. FIG. 1G is a cross section through the distal stopper carried by the stirrer. FIG. 1H is a cross section through an alternative distal stopper. FIG. 2A is a side elevational view of a torque wire that rotates the distal end of the aspiration catheter. FIG. 2B shows a torque wire in association with a distal stopper configured as a torque ring. FIG. 2C shows a torque wire in association with a distal stopper configured as a torque ring. FIG. 3A is a side elevational view of an axially unconstrained obstruction engaging wire within an access catheter. FIG. 3B is a side elevational view of an obstruction engaging wire having a limited distal range of motion beyond the distal end of the catheter. FIG. 3C is a side elevational view of an obstruction engaging wire having a limited distal range of motion beyond the distal end of the catheter. FIG. 4 is a side elevational view of a driver wire for use with the catheter of FIGS. 1A and 1B. FIG. 5A is a side elevational view of a flow assisted wire for use with a catheter having a stop ring. FIG. 5B is a side elevational view of a flow-assisted wire for use with a catheter having a stop ring. FIG. 5C shows a steerable wire for use with a catheter having a stop ring. FIG. 5D is a detailed view of the distal end of the steerable wire of FIG. 5C. FIG. 5E is a side elevational view of the wire of FIG. 5C in a deflected configuration. FIG. 6A shows various distal cap embodiments that couple the core wire to the annular flange at the stirrer tip. FIG. 6B illustrates various distal cap embodiments that couple the core wire to the annular flange at the stirrer tip. FIG. 7A illustrates a cross-sectional elevation view of a catheter wall according to one embodiment. FIG. 7B illustrates a cross-sectional elevation view of a catheter wall according to another embodiment, showing one or more axially extending filaments. FIG. 7C depicts a side elevational view of the catheter. FIG. 7D illustrates a cross-sectional view through a catheter having a sidewall with one or more axially extending filaments. FIG. 7E is a side elevational cross section through the beveled tip of a distal catheter or extension tube tip. FIG. 8A shows a side elevational view of a catheter according to one embodiment. FIG. 8B depicts a cross-sectional elevation taken along line AA of FIG. 8A. FIG. 8C illustrates a cross-sectional view taken along line BB of FIG. 8A. FIG. 9A shows a side elevational view of a catheter according to another embodiment. FIG. 9B depicts a cross-sectional elevation view taken along line AA of FIG. 9A, showing one or more axially extending filaments. FIG. 9C illustrates a cross-sectional view taken along line BB of FIG. 9A, showing one or more axially extending filaments. FIG. 10A is a side elevational cross section through a blunted, beveled distal catheter or extension tube tip. FIG. 10B is a side elevational section through a blunted, beveled distal catheter or extension tube tip. FIG. 11A is a side elevational cross section through a sinusoidally shaped distal catheter or extension tube tip. FIG. 11B is a perspective view of a distal catheter or extension tube tip that is sinusoidally shaped. FIG. 12 shows a schematic diagram of a computational fluid dynamics (CFD) velocity field model. FIG. 13A shows images from a numerical simulation of clot aspiration using the model of FIG. 12, illustrating the initial state after some aspiration has occurred. FIG. 13B shows images from a numerical simulation of clot aspiration using the model of FIG. 12, illustrating effective aspiration. FIG. 14 graphically depicts the percent increase in aspirated material for the catheter distal tip shapes shown in FIGS. 7E, and 10A-11B as a percent improvement over the flat or planar catheter distal tip shape shown in FIG. 3A. FIG. 15A illustrates the CFD velocity field profile for a flat or planar catheter distal tip. FIG. 15B illustrates the CFD velocity field profile for a catheter distal tip with a 30° angle. FIG. 15C illustrates the CFD velocity field profile for a catheter distal tip with an angle of 60°. FIG. 16A shows the uptake length of a beveled distal catheter tip. FIG. 16B shows the uptake length of a blunted, beveled distal catheter tip. FIG. 17 graphically depicts the percent increase in aspirated material for the catheter distal tip configurations shown in FIGS. 7E and 10A-11B as a percent improvement over the flat, vertical catheter distal tip configuration shown in FIG. 3A. FIG. 18A illustrates a side elevational view of a catheter with progressively enhanced flexibility, according to one embodiment. FIG. 18B is a proximal end view of the enhanced flexibility catheter of FIG. 18A. FIG. 19 illustrates back-up support for a catheter in accordance with the present invention. FIG. 20 illustrates a graph of the elastic modulus or durometer of the catheter along its length from the proximal end to the distal end. FIG. 21 shows a graph of the bend test profile of a catheter according to the present invention compared to a conventional catheter.

With reference to FIG. 1, a catheter 10 in accordance with one aspect of the present invention is disclosed. Although described primarily in the context of an elongated flexible catheter, such as a thrombus clot retrieval catheter having a single central lumen, the catheter of the present invention can be readily modified to incorporate additional features, such as a permanent or removable column strength enhancing mandrel, two or more lumens to allow for injection of drugs, contrast agents, or perfusion agents, or to provide inflation media to an inflatable balloon carried by the catheter, or combinations of these features, as will be readily apparent to those skilled in the art in view of the disclosure herein. Additionally, although the present invention will be described primarily in the context of removing occlusive material from remote vasculature in the brain, it has applicability as an access catheter for delivery and removal of any of a variety of diagnostic or therapeutic devices, with or without aspiration.

The catheters disclosed herein are readily adaptable for use anywhere in the body where it may be desirable to position a catheter configured to precisely limit the axial intracatheter distal advancement of other internal catheter components or tools throughout the body. For example, catheter shafts in accordance with the present invention may be sized for use throughout either the venous or arterial sides of the neurovasculature, the coronary and peripheral vasculature, the gastrointestinal tract, the urethra, ureters, fallopian tubes, and other lumens and possible lumens. Specific applications include clot removal in cases of ischemic stroke, deep vein thrombosis, and pulmonary embolism. The catheter structures of the present invention may also be used for minimally invasive percutaneous tissue access, such as access to bones such as the spine for diagnostic or therapeutic access to solid tissue targets (e.g., breast or liver or brain diagnosis or treatment), delivery of laparoscopic tools, or delivery of devices where precise axial control can be of advantage.

The catheter 10 generally includes an elongated tubular body 16 extending between a proximal end 12 and a distal working end 14. The length of the tubular body 16 depends on the desired application. For example, lengths in the range of about 120 cm to about 150 cm or more are typical for use in percutaneous transluminal coronary applications with transfemoral access. Intracranial or other applications may require different catheter shaft lengths depending on the vascular access site, as will be understood in the art.

With reference to FIG. 1B, any of the catheters disclosed herein may include an axial restraint device 2402 that cooperates with a complementary stop on an internal component, such as a rotation device, to allow rotation of the device but limit the range of distal axial movement of the internal device. This allows for precise positioning of the distal tip of the internal device relative to the distal end of the catheter, independent of bending of the catheter shaft, and prevents the distal tip of the internal device from extending beyond a preset position, such as the distal end of the catheter.

In the illustrated implementation, the distal restraint device or restraining component 2402 includes at least one protrusion extending radially inward from the inner surface of the tubular body, which protrusion is configured to restrict the inner diameter of the aspiration lumen and provide a bearing surface for engaging the distal surface carried by the agitator. The restraint device may include one or two or three or four or more protrusions, such as tabs, or may include a continuous or segmented annular ring that provides a substantially continuous, annular, proximally-facing restraining surface, as illustrated in FIG. 1B. The proximal bearing surface 2405 of the axial restraint device 2402 may be located within about 50 cm, 30 cm, or 15 cm from the distal end of the tubular body, for example within about 4 cm to about 12 cm from the distal end.

Alternatively, the bearing surface 2405 may be provided at the proximal end of the catheter 10 depending on the desired performance and intended vasculature. For example, the proximal hub 15 may include an internal bearing surface 11 that slidably engages a complementary distal bearing surface carried by the core wire. Alternatively, an outer surface 13 carried by the hub 15, e.g., an annular surface surrounding a central lumen, may be adapted to slidably engage a complementary distal surface carried by a control wire handle, discussed below.

To optimize alignment of the inner device's distal rotatable tip with the catheter's distal port, and to decouple that axial alignment from tortuosity in the vascular pathway that would otherwise change the relative axial position of the catheter exit port and tip, the proximal bearing surface of the axial restraint device is often within about 3 mm to about 50 mm, in some implementations within about 5 mm to about 20 mm, and in one implementation within about 6 mm to about 14 mm, from the catheter's distal port.

The distal restraining device may be a circular band or ring or protrusion 2402 of metal (e.g., nitinol, stainless steel, aluminum, etc.) or polymer attached to or incorporated into the inner surface of the sidewall of the catheter 2403 near the distal tip, with the distal restraining component 2402 extending into the ID of the catheter. Additionally, the distal restraining component 2402 may be radiopaque for visibility under fluoroscopy. The distal restraining component 2402 carries a proximally facing surface 2405, which may be, for example, an annular, circumferential bearing surface that extends into the inner diameter of the catheter and interfaces with a distal stop 2414 on the rotating assembly. See FIG. 1C. For example, the distal stop 2414 may be an annular feature on the rotating assembly that interfaces with the distal restraining component 2402 of the catheter to stop distal advancement and prevent displacement of the distal tip beyond the catheter distal tip.

In one implementation, the ring 2402, in its relaxed form before being secured within the catheter lumen, is C-shaped or cylindrical with slits extending axially to form a split ring. The ring 2402 is compressed using a fixation device that shrinks the ring into a closed circular shape, allowing it to slide within the catheter (e.g., 0.071 inches). When the ring is released from the fixation device, it expands radially to the maximum diameter allowed by the inner diameter of the catheter. The radial force of the ring engages the inner surface of the catheter and resists axial displacement under the applied forces of intended use. In another implementation, the ring is a completely closed, continuous annular structure (like a typical marker band) whose distal end flares slightly radially outward to form a locking edge. The ring is inserted into the catheter from the distal end. When an axial force is applied from the proximal side, the flared portion with the locking edge holds the ring in place.

Alternatively, the distal restraint may be formed by forming radially inwardly directed folds in the catheter body or by introducing bearing surfaces that penetrate the wall of the catheter and communicate with the central lumen, for example by introducing at least one or two or more protrusions that penetrate the wall and enter into the lumen. The restraint may take the form of a concentric inner tube having an axial length of at least about 1 mm or 2 mm or more, but generally less than about 5 cm or 3 cm or 2 cm. Depending on the nature of the distal restraint, it may be secured by a mechanical interference fit, a friction fit, or a bond formed by any of a variety of bonding techniques, including adhesive bonding and thermal bonding.

1C and 1D, the inner member takes the form of a clot retrieval device 2401. The rotatable core wire distal section 2407 includes a torque coil 2412 surrounding a core wire 2410. The torque coil 2412 includes an outer coil 2413 concentrically surrounding an inner coil 2415 having opposing windings. The coil 2412 is shown as having a constant diameter, which leaves an internally trapped space between the coil and the core wire as a result of the tapered core wire. Optimally maximizing the area of the aspiration lumen between the coil and the corresponding inner wall of the catheter allows the diameter of the coil 2412 to taper distally to follow the taper of the core wire. This can be accomplished by winding the coil on a core wire that acts as a tapered mandrel, or by using other techniques known in the art. When doing this, the OD of the core wire tapers distally while the area of the aspiration lumen tapers distally.

The proximal end of the core wire 2410 is provided with a handle configured to manually rotate the core wire. The handle may be a molded part, such as a knob, with axially oriented surface features, such as ridges, flats, or grooves, to enhance grip. The handle may have two opposing tabs extending in opposite directions from the axis of the core wire and may be rotated using two or three fingers.

1E and 1F, the torque coil 2412 extends between a proximal end 430 and a distal end 432. The proximal end 430 is affixed to a tapered section of the core wire 2410. As illustrated in FIG. 1E, the core wire 2410 tapers from a larger diameter in the proximal zone to a smaller diameter in the distal zone 434, with a distal transition 436 between the tapered section and the distal zone 434, which may have a substantially constant diameter throughout. The inner diameter of the inner coil 2415 is complementary to (approximately the same as) the outer diameter at the proximal end 430 of the core wire 2410. The tapered section of the core wire 2410 extends proximally from the distal transition 436 to a proximal transition (not shown) where the core wire 2410 has a constant diameter.

The torque coil 2412 may additionally include a proximal radiopaque marker and/or connector, such as a solder joint 438. In the illustrated implementation, the proximal connector 438 is in the form of an annular silver solder band that surrounds the inner coil 415 and abuts the proximal end of the outer coil 2413.

The axial length of the torque coil 2412 is within a range of about 10 mm to about 50 mm, and in some embodiments, within a range of about 20 mm to about 40 mm. The distal transition 436 and distal stop 2414 may be positioned within a range of about 5 mm to about 20 mm, and in some implementations, within a range of about 8 mm to about 12 mm, from the proximal end of the distal cap 2420.

1E-1I, the distal stop 2414 may include one or two or three or more spokes 440 extending radially outward from the outer coil 413 and may optionally be supported by an annular hub 442 carried by the torque coil 2412. The spokes 440 support a slider 441 having a peripheral surface 442 configured to fit snugly within the inner diameter of the delivery catheter lumen. Preferably, at least three or four or five or more spokes 440 are provided, equidistantly spaced apart for rotational balance. In the illustrated embodiment, three spokes 440 are provided, spaced approximately 120° apart around the circumference of the torque coil 2412.

In the illustrated embodiment, the spokes or struts 440 have an axial length greater than their width measured circumferentially and extend parallel to the longitudinal axis of the catheter. Alternatively, the spokes 440 can be oriented in a helical configuration to form a propeller that can assist in transporting material in a proximal direction during rotation. The leading edges can be sharpened to simultaneously cut the thrombus engaged by rotation of the core wire while applying a vacuum to the central lumen.

The distal stop 2414 carries a plurality of distal surfaces 446, e.g., on the slider 441. The distal surfaces 446 are configured to slidably engage a proximal surface of a stop device on the inner diameter of the delivery catheter, e.g., a proximally facing surface 2405 on a radially inwardly extending annular flange or ring 2402. See FIG. 1B, discussed above. This creates a sliding interference fit with the bearing surfaces, allowing the distal stop 2414 to rotate within the delivery catheter and move axially distally to or short of where the distal surfaces 446 slidably engage the proximal surface 2405 on the stop ring 2402.

Referring to FIG. 1E, the distal end 432 of the torque coil 2412 includes a distal cap 2420. The distal cap 2420 may include an annular band, such as a radiopaque marker band, that is bonded to the outer surface of the inner coil 2415 and axially distally adjacent or overlapping the distal end of the outer coil 2413. A proximally extending appendage, such as an annular flange 2417, may be provided on the stirrer tip 2416 for coupling to the distal cap 2420, and in the illustrated embodiment, to the outer coil 2413. The distal cap 2420 may also be coupled directly or indirectly to the distal end of the core wire 2410.

The agitator tip 2416 includes a distal end 450 and a proximally extending helical flange 452 that increases in diameter proximally to a maximum diameter and then decreases in diameter proximally to a minimum diameter that may be larger than the diameter at the distal end. The flange may extend at least approximately one full turn, and generally less than about 5 or 4 or 3 turns, around the longitudinal axis extension of the core wire 2410. The helical flange includes a rounded, blunted edge 454 that is configured to slidably rotate within the tubular delivery catheter.

The maximum OD of the tip 2416, measured at the axial working location of the tip 2416 when the stopper 2414 is engaged with the stop ring, is generally at least about .005 inches, and preferably at least about 0.01 inches or 0.015 inches or more, less than the ID of the catheter aspiration lumen through which the embolism treatment system 2401 is intended to be advanced. For example, a tip having a maximum OD in the range of about 0.050 to about 0.056 inches will be positioned within a catheter having a distal ID in the range of about 0.068 to about 0.073 inches, and in one embodiment about 0.071 inches. With the tip in the center of the lumen of the delivery (aspiration) catheter, the tip is spaced from the inner wall of the catheter by a distance in all directions of at least about 0.005 inches, and in some embodiments at least about 0.007 inches or 0.010 inches or more.

In this way, an unobstructed flow path is created in the annular space between the maximum OD of the tip and the ID of the catheter lumen. This annular flow path cooperates with the vacuum and the helical tip to grasp and draw occlusive material into the catheter under rotation and vacuum. The annular flow path is significantly larger than any flow path created by manufacturing tolerances in the tip that is configured to shear embolic material between the tip and the catheter wall.

Additional suction volume is obtained as a result of the helical communication defined between each two adjacent thread forms of the tip. The cross-sectional area of the helical flow path of a tip having a maximum OD within the range of about 0.050 inches to about 0.056 inches is generally at least about 0.0003 square inches, in some embodiments at least about 0.00035, or at least about 0.000375 inches. Thus, the total suction flow path across the helical tip is the sum of the helical flow path through the tip and the annular flow path defined between the OD of the tip and the ID of the catheter lumen.

The rounded edges 454 on the thread form 452, combined with slow manual rotation of the tip through less than about 20, or less than about 10, or less than about 5 turns, and the space between the thread form 452 and the inner wall of the catheter, allow for both aspiration through the helical communication formed between adjacent helical thread forms and aspiration around the outside of the tip 2416, with the assembly configured to engage and capture embolic material, but not shear it between the sharp edges and the inner wall of the catheter. Once engaged, further rotations pull the aspiration catheter distally past the clot, anchoring the proximal portion of the clot to facilitate proximal retraction and removal. The axial length of the tip 2416, including the appendage sleeve 2417, is generally less than about 6 mm, and preferably less than about 4 mm, or 3 mm, or 2.5 mm or less, depending on the desired performance.

The pitch of the thread form 452 may vary generally within a range of about 35 degrees to about 80 degrees depending on the desired performance. A thread form pitch within a range of about 40 degrees to about 50 degrees may work best for hard clots, while a pitch within a range of about 50 degrees to about 70 degrees may work best for soft clots. In some implementations, the pitch is within a range of about 40 degrees to about 65 degrees, or within a range of about 40 degrees to about 50 degrees.

The tip 2416 may additionally include features to attract and/or enhance adhesion of blood clots to the tip. For example, the tip may be textured, such as a microporous, microparticulate, nanoporous, or nanoparticulate surface, by treating the tip material or applying a coating. A coating of a component that attracts blood clots, such as a polymer or drug, may be applied to the surface of the tip. For example, a coating of roughened Polyurethane (Tecothane, Tecoflex) may be applied to at least the threaded surface and optionally the entire tip. The polyurethane may preferably be roughened after coating, for example by solvent treatment, and the surface of the tip may be roughened prior to coating to enhance adhesion of the coating to the tip.

Alternatively, the core wire 2410 may include an insulating coating, which allows a negative charge to be delivered to the tip to attract the thrombus. Two conductors may extend the entire length of the body, for example in a coaxial configuration. Energy parameters and considerations are disclosed in U.S. Pat. No. 10,028,782 to Orion and U.S. Patent Publication No. 2018/0116717 to Taff et al., the disclosures of each of which are expressly incorporated herein by reference in their entirety. As a further alternative, the tip 2416 may be cryogenically cooled to create a small cryoadhesion between the tip and the thrombus. Considerations for forming small cryogenic tips for intravascular catheters are disclosed in U.S. Patent Publication No. 2015/0112195 to Berger et al. and U.S. Patent Publication No. 2018/0116704 to Ryba et al., the disclosures of each of which are expressly incorporated herein by reference in their entireties.

Referring to FIG. 1G, a cross section through the distal stopper 2414 is illustrated in which the slide 441 is a continuous circumferential wall with a continuous peripheral bearing surface 442. Three struts 440 are spaced apart and define three flow passages 443 extending axially therethrough. The sum of the surface areas of the leading edges of the struts 440 is preferably minimized as a percentage of the sum of the surface areas of the open flow passages 443. This allows for a maximum area for aspiration while also providing sufficient support axially for the distal surface 446 (see FIG. 1F) to engage a complementary stop surface on the inner wall of the catheter and to prevent the tip 2416 from advancing distally beyond a preset relationship with the catheter. The sum of the leading (distal-facing) surface areas of the struts is generally less than about 45% of the sum of the areas of the flow passages 443, and typically less than about 30%, or 25%, or 20%.

In an embodiment having a torque coil 2412 with an OD of about 0.028 inches, the OD of the stopper 2414 is about 0.068 inches. The wall thickness of the strut is generally less than about 0.015 inches, typically less than about 0.010 inches, and in some implementations less than about 0.008 inches, or 0.005 inches or less. The strut 440 has a catheter axial length sufficient to support the assembly against distal movement past the catheter stop ring, and may be at least about 50% of the OD of the stopper 2414. For a stopper 2414 with an OD of about 0.68 inches, the strut 2440 has an axial length of at least about 0.75 mm, or 0.95 mm.

With reference to FIG. 1H, a stopper 2414 is illustrated having three different sliders 441, each supported by a unique strut 440. The sum of the circumferential portions of the three peripheral surfaces is preferably about 75% or less, and in some implementations about 50% or less, or 40% or less, of the total circumference of the continuous peripheral surface 442 as in FIG. 1G. This further increases the cross-sectional area of the flow passage 443. For catheters having a hub 443 with an ID of about 0.07 inches or less and an OD of at least about 0.026 or 0.028 or 0.030 or more, the sum of the flow passages 443 is at least about 0.0015 inches, preferably at least about 0.020, or 0.022 inches or more. The area of the leading edges of the struts 440 and sliders 441 is preferably less than about .003 inches, more preferably less than about 0.001 inches, or 0.0008 inches or less. In the catheter axial direction, the length of the strut 440 is at least about 0.50 mm, or 0.75 mm, and in one embodiment, the length of the strut 440 and the slider 441 is about 1 mm.

One method for using the above system is described below: Introduce the .088LDP guide catheter and advance it until the catheter tip is slightly proximal to the embolic site, if possible. Introduce the .071 aspiration catheter of FIG. 1A and 1B through the .088LDP and advance it until the catheter tip reaches the clot surface. Remove any intermediate catheters or guidewires, if applicable. Introduce the rotatable corewire so that its distal tip is flush with the distal end of the .071 aspiration catheter. Seal the proximal RHV and apply vacuum to the .071 aspiration catheter using the aspiration pump. Rotate the corewire manually between about 2 and 10 times, generally no more than 20 times, to engage the clot without cutting it, pull the catheter partially distally past the clot, and discontinue rotating the corewire.

The aspiration catheter is now tethered to the clot using both vacuum and mechanical engagement. The 088LDP guide catheter is advanced over the aspiration catheter, which acts like a guidewire, until the 088 catheter reaches the surface of the clot. A vacuum source, such as a VacLok syringe, is used to apply vacuum to the 088LDP guide catheter. The aspiration catheter, with the clot affixed to its tip, is retracted proximally through the 088LDP guide, maintaining the position of the 088LDP at the site of the embolism.

If flow is not restored through the 088LDP, the core wire may be removed from the aspiration catheter. If necessary, the spiral tip of the core wire may be wiped to remove residual clots, and the core wire and aspiration catheter may be returned to the embolization site and the clot retrieval procedure repeated until flow is restored. Once flow is restored, the 088LDP guide catheter is removed.

In accordance with another aspect of the present invention, a torque transmission system is provided for changing the rotational orientation of the distal end of a highly flexible catheter shaft. A particular highly flexible catheter, further discussed in connection with, for example, FIG. 7E, has an elliptical opening cut with a bevel at the tip. One feature of the beveled tip is to aid in navigation and clot aspiration. Ideally, the beveled cut may be oriented such that the large elliptical opening created faces the clot as directly as possible, even in a tortuous or branching vasculature. Neurovascular catheters in general, and the distal wall structures disclosed herein in particular, exhibit poor torque transmission, so that rotating the proximal end of the catheter does not result in the same degree of predictable rotation at the distal end due to the flexible structure and thin walls. As such, it is not practical to attempt to orient the beveled tip by applying torque directly to the catheter from the proximal end.

With reference to FIG. 2A, a torque wire is provided that transmits torque directly to the distal zone of the catheter. A distal stop 2414, such as a circular ring, is attached to the core wire in a manner similar to that discussed in connection with FIG. 1C. The portion of the core wire 2410 that extends beyond the distal transition 436 (see FIG. 1E) may be omitted, leaving the distal stop 2414 at the distal end of the torque wire. Alternatively, a short leading section of the core wire may extend distally beyond the distal stop 2414 as a centering guide. The distal stop 2414 carries a distal face that carries at least one, and generally at least two or three or more, engagement elements 2415 for rotationally engaging complementary engagement structures within the catheter lumen.

2B and 2C, the catheter tubular body 16 carries the distal constraint 2402 as previously discussed. The proximal face includes at least a second engagement structure 2417 that rotationally engages with at least a first engagement structure 2415 on the distal face of the distal stop. In FIGS. 2A and 2B, the engagement structures are complementary interlocking ramp teeth that allow the distal face 2415 formed on the distal end of the torque-enabled guidewire and the proximal face of the distal constraint 2402 to engage and interlock with each other. This provides a mechanical linkage that transmits torque to rotate the catheter in response to rotation of the wire.

2A and 2B, the engagement component includes an axially distally extending protrusion having a first surface 2419 extending substantially parallel to the longitudinal axis of the wire and an opposing inclined surface 2421 extending at an inclination angle of at least about 15 or 20 degrees or more relative to the longitudinal axis. Complementary protrusions and intervening recesses on the stop ring may engage to rotate the stop ring in response when the wire is rotated in a first direction, but may ride over each other to prevent the catheter from rotating in response to rotation of the wire when the wire is rotated in a second, opposite direction.

The configuration of FIG. 2B may be integrated into any of the systems of FIGS. 1A-1H. This allows the wire to be rotated in a first direction to rotate the catheter within the blood vessel and to a desired rotational position adjacent the occlusion. The wire may then be rotated in a second, opposite direction to rotate the tip 2416 to engage the occlusion for ease of removal, as previously described.

Alternatively, these complementary engagement surfaces may be bidirectional, engaging in either rotational direction, e.g., at least one protrusion on the wire that engages with at least one recess on the catheter. In the illustrated embodiment, the engagement structure 2415 includes at least one tooth having a square edge that rotationally engages with a corresponding recess, such as an axially extending slot. (See, e.g., FIG. 3B). This allows for coupling and rotation of the catheter in either direction.

Alternatively, either or both of the complementary engagement surfaces carried by the distal stopper 2414 and the distal restraint device 2402 may include friction enhancing features, such as a textured surface, or a material or coating, that have sufficient increased friction to transfer sufficient torque from the core wire to the catheter body to rotate and redirect the tip of the catheter, for example to enter or avoid a side branch or to provide a different relationship between the catheter and embolic material.

If the angular orientation of the clot and catheter (see FIG. 7E) is not favorable for presenting the largest opening of the catheter directly toward the clot, the wire can be advanced against the internal stop ring of the catheter to engage complementary engagement surfaces, and a torque can be applied with the wire to rotationally reorient the catheter tip to be more favorable for clot aspiration.

In addition, the catheter tip may be rotated during distal advancement of the catheter through a tortuous vasculature to optimize the angular orientation of the beveled tip to facilitate distal advancement of the catheter. Thus, the beveled catheter tip can be precisely rotated to avoid getting caught in arterial branches or calcific deposits.

In the implementation illustrated in FIG. 3A, a torque wire such as a clot retrieval device 2401 is similar to that illustrated in FIG. 1C, except that there is no distal stop 2414. In this implementation, the clot retrieval device can be freely axially advanceable through the lumen of the outer catheter 2403 and beyond the distal end of that catheter. The clot retrieval device 2401 can be advanced distally to engage the clot, and the outer catheter 2403 can be advanced distally over the wire while having traction on the clot retrieval device, and optionally applying a vacuum through the catheter 2403 to grasp and remove the clot.

Alternatively, the helical tip 450 can be rotated into and optionally through the occlusion clot to act as an anchor on the wire. The catheter 2403 may be withdrawn proximally, leaving the anchored core wire 2410 in place. The core wire 2410 can then be used as a guide wire to guide other interventional devices over or along the wire to reach the occlusion to perform additional functions. The core wire 2410 may include an elongated central lumen extending between a proximal port at the proximal end and a distal port at the distal tip 450. Following placement of the distal tip, a guide wire may be advanced through the central lumen and, if the distal tip 450 has been rotated distally enough, the guide wire may be advanced through the embolus. The tip 450 and core wire 2410 may then be counter-rotated to disengage the obstruction and withdrawn proximally from the patient, leaving the guidewire in place for subsequent procedures.

In an alternative configuration, the catheter 2403 may include a second lumen, such as for irrigation, aspiration, or receiving a guidewire therethrough, extending axially from the proximal port to a distal opening at or near the distal end 14. At a desired point in the procedure, the helix and catheter 2403 may be withdrawn proximally, leaving the guidewire in place for further access.

In the implementation illustrated in Figures 3B and 3C, the torque wire and complementary catheter are configured similarly to Figures 1A-1H, except that the distal tip 450 is allowed to extend a controlled distance slightly beyond the distal end 14 of the catheter 10. In Figure 3B, the distal tip 450 is approximately axially aligned with the distal end 14 of the catheter 10 (or the distal tip 3132 in Figure 6E). This leaves an axial gap 18 between the complementary stop surface on the axial restraint device 2404 and the distal stopper 2414. As illustrated in Figure 3C, contacting the complementary stop surfaces allows the distal tip 450 to extend outside the catheter by a maximum of the distance 18. The distance 18 may be at least about .5 mm or about 1 mm or 2 mm, but may generally be about 1.5 cm or 1 cm or 0.5 cm or less, depending on the desired functionality. In some embodiments, the distance 18 is within the range of about 0.5 to 3 mm.

Alternatively, the maximum distal extension distance 18 may be related to the pitch of the helical thread form. For example, 18 may be a distance equivalent to the axial length of about 1 to about 5 turns of the thread form, and preferably may be in the range of about 1 to about 3 turns of the thread form.

In use, the distal tip 450 of the system of FIGS. 3B and 3C can be extended beyond the catheter and rotated to engage the embolus. As the helix rotates, it pulls the catheter forward (distally), allowing the helix to advance further distally over the core wire.

A further application of a distal stop on the wire structure is illustrated in FIG. 4. The core wire 2410 extends only as far as approximately the transition 436 (FIG. 1E), so that the distal stop resides at the distal end of the wire. The distal surface 2411 on the distal stop 2414 can be used to strike the proximal surface 2405 on the distal restraint device 2402 (see FIG. 1B) to provide a jack hammer effect, pulling the catheter from the distal end rather than pushing it from the proximal end. The striking can be low frequency, achieved manually by the clinician, or high frequency, such as at least about 10 Hz or 100 Hz or ultrasonic, depending on the catheter configuration and the desired clinical outcome.

This configuration may reduce the column strength requirements along the length of the catheter body, at least from a pushability standpoint. Maintaining hoop strength is still desirable in catheters intended to be deployed under vacuum. However, in non-vacuum devices, the catheter sidewalls may be reduced if the target site can be reached by "pulling" the catheter distally from the distal restraint device 2402, rather than pushing from the proximal manifold.

5A and 5B, side elevational views of a blood flow assisted access wire for use with a catheter having a stop ring are illustrated. The wire 2410 carries a stopper 2414 that limits distal movement of the wire relative to the catheter by an interference fit with the stop ring 2402 as previously discussed. A force transfer component 2440 is carried by the wire 2410 and is configured to move between a radially contracted configuration (FIG. 5A) for positioning within the catheter and a radially expanded configuration (FIG. 5B) when advanced distally out of the catheter. The force transfer component 2440 is adapted to at least partially impede blood flow and transfer a distally directed force to the wire 2410. Responsive distal downstream advancement of the force transfer component 2440 engages the stopper 2414 with the stop ring 2402 and pulls the catheter in a forward direction.

In the illustrated implementation, the force transfer component 2440 includes a cone-shaped membrane, such as a filter, having an open proximal end 2442 and a closed distal end 2444. The proximal opening 2442 may be supported by a nitinol wire loop, which is connected to the wire 2410 by angled struts 2446. The angled struts 2446 facilitate re-entry of the force transfer component 2440 into the distal end of the catheter upon proximal withdrawal of the wire 2410.

In alternative implementations of the invention, the force transfer component 2440 may include alternative structures for capturing forces from the blood flow, including an inflatable balloon. The wire 2410 may include a central lumen extending its entire length and communicate with the balloon to achieve inflation and deflation as understood in the art.

With reference to Figures 5C-5E, a wire 2410 is illustrated having a steerable distal region 2450. The steering region 2450 may include a tubular body having a first side 2452 that is relatively axially non-contractile. A second, typically opposing, side includes a plurality of transverse elongated slots 2454 that permit axial contraction. A pull wire 2456 is attached to the distal end of the steering zone 2450. Proximal retraction of the pull wire 2456 relative to the tubular body causes axial contraction of the transverse elongated slots 2454 and resulting bending, as shown in Figure 5E.

Any catheter shaft, or portion of a catheter shaft, in accordance with the present invention may include a multi-layered structure that is highly flexible and highly pushable enough to reach deep into the cerebral vasculature, for example, deep into at least the conus, cavernosum, or cerebral divisions of the internal carotid artery (ICA).

In one example, referring to FIG. 7A, the catheter 3000 may have an effective length from the manifold to the distal tip of about 70 cm to about 150 cm, about 80 cm to about 140 cm, about 90 cm to about 130 cm, about 100 cm to about 120 cm, or about 105 cm to about 115 cm. The outer diameter of the catheter 3000 may be about 0.07 inches to about 0.15 inches, about 0.08 inches to about 0.14 inches, about 0.09 inches to about 0.13 inches, about 0.1 inches to about 0.12 inches, or about 0.105 inches to about 0.115 inches, and may be smaller in the distal section than in the proximal section. The inner diameter 3108 of the catheter 3000 in a single central lumen embodiment may be about 0.11 inches or more, about 0.1 inches or more, about 0.09 inches or more, about 0.088 inches or more, about 0.08 inches or more, about 0.07 inches or more, about 0.06 inches or more, or about 0.05 inches or more. The inner diameter 3108 of the catheter 3000 in a single central lumen embodiment may be about 0.11 inches or less, about 0.1 inches or less, about 0.09 inches or less, about 0.088 inches or less, about 0.08 inches or less, about 0.07 inches or less, about 0.06 inches or less, or about 0.05 inches or less.

With reference to FIG. 7A, the inner liner 3014 may be formed by dip coating a mandrel (not shown) to provide a thin-walled, tubular inner layer of the catheter body 3000. The dip coating may be produced by coating a wire, for example a silver-coated copper wire, in PTFE. The mandrel may then be axially stretched to reduce its diameter and removed to leave the tubular inner liner.

The outer surface of the tubular inner liner 3014 may then be coated with a soft tie layer 3012, such as polyurethane (e.g., Tecoflex™), to produce a layer having a thickness of about 0.005 inches or less, and in some implementations approximately 0.001 inches. The tie layer 3012 will generally extend along the most distal about 10 or 20 cm of the catheter shaft 3000, generally less than about at least 50 cm, and in one implementation may extend approximately the distal 30 cm of the catheter shaft 3000, 3100.

A braid, such as a 75 ppi stainless steel braid 3010, may then be wrapped around the inner liner 3014 through the proximal zone to the distal transition 3011. A coil 3024 including a shape memory material, such as a Nitinol alloy, may then be wrapped around the inner liner 3014 from the distal transition 3011 to the distal end of the catheter 3000. In one implementation, the Nitinol coil has a transition temperature below body temperature such that Nitinol remains in an austenitic (springy) state at body temperature. Adjacent loops or threads of the coil 3024 may be tightly wound in the proximal zone and more loosely spaced between adjacent loops in the distal section. In embodiments having a coil section 3024 whose axial length is between about 20% and about 30% of the total catheter length (e.g., a 28 cm coil length in a 110 cm catheter shaft 3000), the distal at least 1, or 2, or 3, or 4 cm of the coil will have a spacing that is at least about 130% of the spacing in the proximal coil section, and in some implementations at least about 150% or more. In a 110 cm catheter shaft 3000 with Nitinol coils, the spacing in the proximal coil may be about 0.004 inches, and in the distal section may be at least about 0.006 inches, or 0.007 inches or more.

In embodiments including an extension catheter, the distal stretchable section of the catheter may be configured as described above. The length of the coil 3024 may be proportional to the length of the stretchable catheter section or the overall length (e.g., extended length) of the catheter 3000. The coil 3024 may extend from the distal end of the stretchable section for at least about 50%, about 60%, about 70%, about 80%, or about 90% of the length of the stretchable section. In some embodiments, the catheter 3000 or the stretchable section may not include a braid, and the coil 3024 may extend to the proximal end (100% of the length) of the stretchable section.

The distal end of the coil 3024 can be spaced proximally from the distal end of the inner liner 3014 to provide room for, for example, an annular radiopaque marker 3040. The coil 3024 can be retracted proximally from the distal end, in some embodiments, approximately 1 cm, 2 cm, or 3 cm or less. In one embodiment, the distal end of the catheter 3000 includes an inclined distal surface 3006 that lies on a plane having an angle of at least about 10°, or about 20°, and in one embodiment, about 30°, relative to the longitudinal axis of the catheter 3000. The radiopaque marker 3040 can lie in a plane transverse to the longitudinal axis. Alternatively, at least the distally facing edge of the annular radiopaque marker 3040 can be elliptical, lies on a plane that is inclined relative to the longitudinal axis and complementary to the angle of inclination of the distal surface 3006. Further details are provided below in relation to Figure 7E.

After the proximal braid 3010, distal coil 3024, and RO marker 3040 are applied, an outer jacket 3020, such as shrink-wrap tubing, may be applied around the catheter body 3000. The outer shrink-wrap sleeve 3020 may comprise any of a variety of materials, such as polyethylene, polyurethane, polyether block amide (e.g., PEBAX™), nylon, or others known in the art. Sufficient heat is applied to cause the polymer to flow and embed into the proximal braid and distal coil.

In one implementation, the outer shrink-wrap jacket 3020 is formed by sequentially advancing a number of short tubular sections 3022, 3026, 3028, 3030, 3032, 3034, 3036, 3038 concentrically over the catheter shaft subassembly and applying heat to shrink the sections onto the catheter 3000 to provide a smooth, continuous outer tubular body. The structure may extend along at least the distal-most 10 cm of the catheter body 3000, and preferably at least about the distal-most 20 cm, 25 cm, 30 cm, 35 cm, 40 cm, or greater than 40 cm. The entire length of the outer shrink-wrap jacket 3020 may be formed from tubular sections, and the length of the distal tubular sections (e.g., 3022, 3026, 3028, 3030, 3032, 3034, 3036, 3038) may be shorter than the tubular section or sections forming the proximal portion of the outer shrink-wrap jacket 3020 to provide a more abrupt transition in flexibility toward the distal end of the catheter 3000.

The durometer of the outer wall sections may decrease distally. For example, the proximal sections, such as 3022 and 3026, may have a durometer of at least about 60 or 70D, with the durometer of successive sections gradually decreasing distally to a durometer of about 35D or 25D or less. The 25 cm section may have at least about three or five or seven or more sections, and the entire catheter 3000 may have at least about six or eight or ten or more distinct flexibility zones. The distal one or two or four or more sections 3036, 3038 may have a smaller post-retraction OD than the more proximal sections 3022-3034, thereby creating a tapered OD in the finished catheter body 3000. The length of the lower OD section 3004 may be in the range of about 3 cm to about 15 cm, and in some embodiments, in the range of about 5 cm to about 10 cm, e.g., about 7 or 8 cm, which may be achieved by providing a lower wall thickness in the distal sections 3036, 3038.

7B and 7D, the catheter may further include a tension support that increases tension resistance in the distal zone. The tension support may include a filament, and more particularly, may include one or more axially extending filaments 3042. The axially extending filaments 3042 may be axially disposed within the catheter wall near the distal end of the catheter. The axially extending filaments 3042 act as a tension support to resist stretching of the catheter wall under tension (e.g., when the catheter is retracted proximally through a tortuous vasculature).

At least one of the axially extending filaments 3042 may extend proximally along the length of the catheter wall from within a range of about 1.0 cm from the distal end of the catheter to less than about 5 cm from the distal end of the catheter, less than about 10 cm from the distal end of the catheter, less than about 15 cm from the distal end of the catheter, less than about 20 cm from the distal end of the catheter, less than about 25 cm from the distal end of the catheter, less than about 30 cm from the distal end of the catheter, less than about 35 cm from the distal end of the catheter, less than about 40 cm from the distal end of the catheter, or less than about 50 cm from the distal end of the catheter.

The axially extending filament or filaments 3042 may have a length of about 50 cm or more, about 40 cm or more, about 35 cm or more, about 30 cm or more, about 25 cm or more, about 20 cm or more, about 15 cm or more, about 10 cm or more, or about 5 cm or more.

At least one of the axially extending filaments 3042 may have a length of about 50 cm or less, about 40 cm or less, about 35 cm or less, about 30 cm or less, about 25 cm or less, about 20 cm or less, about 15 cm or less, about 10 cm or less, or about 5 cm or less. At least one of the axially extending filaments 3042 may extend at least about the most distal 50 cm of the catheter length, at least about the most distal 40 cm of the catheter length, at least about the most distal 35 cm of the catheter length, at least about the most distal 30 cm of the catheter length, at least about the most distal 25 cm of the catheter length, at least about the most distal 20 cm of the catheter length, at least about the most distal 15 cm of the catheter length, at least about the most distal 10 cm of the catheter length, or at least about the most distal 5 cm of the catheter length.

In some implementations, the filament extends proximally from the distal end of the catheter along the length of the coil 24 and terminates proximally within about 5 cm or 2 cm or less on either side of the transition 3011 between the coil 3024 and the braid 3010. The filament may terminate at the transition 3011 without overlapping the braid 3010.

In another embodiment, the most distal portion of the catheter 3000 may include a durometer of less than approximately 35D (e.g., 25D) and may have a length between approximately 25 cm and approximately 35 cm to form a highly flexible distal portion of the catheter. The distal portion may include one or more tubular sections (e.g., section 3038) of the same durometer. A series of proximally adjacent tubular sections may form a transition region between the proximal rigid portion and the distal highly flexible portion of the catheter 3000. The series of tubular sections forming the transition region may have the same or substantially similar lengths, for example, a length of approximately 1 cm.

A relatively short series of tubular sections may provide a steep drop in durometer across the transition region. For example, the transition region may have a proximal tubular section 3036 (proximally adjacent to the distal portion) having a durometer of approximately 35D. The adjacent proximal section 3034 may have a durometer of approximately 55D. The adjacent proximal section 3032 may have a durometer of approximately 63D. The adjacent proximal section 3030 may have a durometer of approximately 72D.

The more proximal section may include a durometer of approximately greater than 72D and may extend to the proximal end of the catheter or extension catheter section. For example, the extension catheter section may include a proximal portion of approximately greater than 72D between about 1 cm and about 3 cm. In some embodiments, the proximal portion may be about 2 cm long. In some embodiments, the most distal section (e.g., 3038-3030) may include PEBAX™ and the more proximal section may include a generally harder material, e.g., Vestamid®.

The inner diameter of the catheter 3000 or catheter extension section may be between approximately 0.06 inches and 0.08 inches, between approximately 0.065 inches and 0.075 inches, or between approximately 0.068 inches and 0.073 inches. In some embodiments, the inner diameter is approximately 0.071 inches.

In some embodiments, the distal-most portion may have a tapered inner diameter, as described elsewhere herein. The taper may occur approximately between the distal highly flexible portion and the transition region (e.g., over the proximal-most portion of the distal highly flexible portion). The taper may be relatively gradual (e.g., occurring over approximately 10 cm or more) or relatively steep (e.g., occurring over approximately less than 5 cm). The inner diameter may taper to an inner diameter of between about 0.03 inches and about 0.06 inches. For example, the inner diameter may be about 0.035 inches, about 0.045 inches, or about 0.055 inches at the distal end of the catheter 3000. In some embodiments, the inner diameter may be constant at least over the catheter extension section.

In some embodiments, the coil 3024 may extend from the distal end of the catheter 3000 proximally along the highly flexible distal portion and terminate at the distal end of the transition region. In other embodiments, the coil 3024 may extend from the distal end of the catheter to the proximal end of the transition region, to a point along the transition region, or proximally beyond the transition region. In other embodiments, the coil 3024 may extend the entire length of the catheter 3000 or catheter extension section, as described elsewhere herein. The braid 3010, if present, may extend from the proximal end of the coil 3024 to the proximal end of the catheter 3000 or catheter extension section.

The axially extending filament or filaments 3042 may be disposed near or radially outward of the tie layer 3012 or inner liner 3014. The axially extending filament or filaments 3042 may be disposed near or radially inward of the braid 3010 and/or coil 3024. The axially extending filament or filaments 3042 may be supported between the inner liner 3014 and the helical coil 3024.

When one or more axially extending filaments 3042 are disposed within the catheter wall, the axially extending filaments 3042 may be disposed radially symmetrically. For example, the angle between two axially extending filaments 3042 relative to the radial center of the catheter may be about 180 degrees. Alternatively, depending on the desired clinical performance (e.g., flexibility, trackability), the axially extending filaments 3042 may be disposed so as to be radially asymmetric. The angle between any two axially extending filaments 3042 relative to the radial center of the catheter may be less than about 180 degrees, about 165 degrees or less, about 150 degrees or less, about 135 degrees or less, about 120 degrees or less, about 105 degrees or less, about 90 degrees or less, about 75 degrees or less, about 60 degrees or less, about 45 degrees or less, about 30 degrees or less, about 15 degrees or less, about 10 degrees or less, or about 5 degrees or less.

The axially extending filament or filaments 3042 may be made of materials such as Kevlar, polyester, Meta-Para-Aramide, or any combination thereof. At least one of the axially extending filaments 3042 may comprise a single fiber or a bundle of multiple fibers, which may have a circular or rectangular cross-section. The term fiber or filament does not convey composition and may include any of a variety of high tensile strength polymers, metals, or alloys depending on design considerations such as desired tensile failure limits and wall thickness. The cross-sectional dimension of the axially extending filaments 3042, measured in the radial direction, may be less than or equal to about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 20%, 25%, or 30% of the cross-sectional dimension of the catheter 3000. The cross-sectional dimension of the axially extending filaments 3042, measured in the radial direction, may be less than or equal to about 0.001 inch, about 0.002 inch, about 0.003 inch, about 0.004 inch, about 0.005 inch, about 0.006 inch, about 0.007 inch, about 0.008 inch, about 0.009 inch, about 0.010 inch, about 0.015 inch, about 0.020 inch, about 0.025 inch, or about 0.030 inch.

The axially extending filament or filaments 3042 may increase the tensile strength of the distal zone of the catheter by at least about 1 lbs, at least about 2 lbs, at least about 3 lbs, at least about 4 lbs, at least about 5 lbs, at least about 6 lbs, at least about 7 lbs, at least about 8 lbs, or at least about 10 lbs or more.

Any of the aspiration catheters or tubular extension sections disclosed herein, whether or not they include an axial filament, may have a beveled distal tip. Referring to FIG. 7E, a distal catheter tip 3110 includes a tubular body 3112 including an advancement section 3114, a marker band 3116, and a proximal section 3118. An inner tubular liner 3120 may extend the entire length of the distal catheter tip 3110 and may include dip coated PTFE.

A reinforcing element 3122, such as a braid or spring coil, is embedded in an outer jacket 3124, which may extend the entire length of the distal catheter tip 3110.

The advancing section 3114 terminates distally in a beveled surface 3126 to provide a leading sidewall portion 3128 having a length measured between the distal end 3130 of the marker band 3116 and the distal tip 3132. The trailing sidewall portion 3134 of the advancing section 3114 has an axial length in the illustrated embodiment approximately equal to the axial length of the leading sidewall portion 3128, measured about 180 degrees around the catheter from the leading sidewall portion 3128. The leading sidewall portion 3128 may have an axial length in the range of about 0.1 mm to about 5 mm, and generally in the range of about 1 to about 3 mm. The trailing sidewall portion 3134 may have a length at least about 0.1 or about 0.5 or about 1 mm or about 2 mm or more shorter than the axial length of the leading sidewall portion 3128, depending on the desired performance.

The beveled surface 3126 is inclined at an angle A in the range of about 45 degrees to about 80 degrees from the longitudinal axis of the catheter. In certain implementations, the angle is in the range of about 55 degrees to about 65 degrees, i.e., in the range of about 55 degrees to about 65 degrees from the longitudinal axis of the catheter. In one implementation, the angle A is about 60 degrees. One result of the angle A being less than about 90 degrees is an elongation of the major axis of the distal port area, which increases the surface area of the port and may enhance the attraction or retention of clots. Compared to the surface area of a circular port (where angle A is 90 degrees), the area of the beveled port is generally at least about 105% and not more than about 130%, in some implementations in the range of about 110% and about 125%, and in one example, about 115%.

In the illustrated embodiment, the axial length of the advancement section is substantially constant around the circumference of the catheter such that the beveled surface 3126 is approximately parallel to the distal surface 3136 of the marker band 3116. The marker band 3116 has a proximal surface that is approximately transverse to the longitudinal axis of the catheter, which results in the marker band 3116 having a right trapezoidal configuration in side elevation. The short sidewall 3138 is rotationally aligned with the trailing sidewall portion 3134 and has an axial length within the range of about 0.2 mm to about 4 mm, and typically within the range of about 0.5 mm to about 2 mm. The opposing long sidewall 3140 is rotationally aligned with the leading sidewall portion 3128. The long sidewall 3140 of the marker band 3116 is generally at least about 10%, or 20% longer than the short sidewall portion 3138, and may be at least about 50%, 70%, or 90% or more longer than the short sidewall portion 3138, depending on the desired performance. Generally, the long sidewall 3140 will have a length of at least about 0.5 mm or 1 mm, and less than about 5 mm or 4 mm.

The marker band may have at least one, and optionally two or three or more, slits extending axially throughout its length to allow for radial expansion. The slits may be located on the short sidewall 3138 or on the long sidewall 3140 or between them depending on the desired bending characteristics. The marker band may comprise any of a variety of radiopaque materials, such as a platinum/iridium alloy, preferably having a wall thickness of about 0.003 inches or less, and in one implementation about 0.001 inches.

The marker band zone of the assembled catheter will have a relatively high bending stiffness and high crush strength, e.g., at least about 50% or at least about 100% less than the proximal section 18, but generally no more than about 200% less than the proximal section 3118. The high crush strength may provide radial support to the adjacent advancement section 3114, particularly the leading sidewall portion 3128, which may help the distal tip 3132 act as an atraumatic shock absorber during transluminal advancement and provide resistance to contraction under vacuum. The proximal section 3118 preferably has a lower bending stiffness than the marker band zone, and the advancement section 3114 preferably has an even lower bending stiffness and crush strength than the proximal section 3118.

The advancing section 3114 may include an outer jacket 3124 and, optionally, a distal extension of the inner liner 3120, without any other internal support structure distal to the marker band 3116. The outer jacket may include extruded Tecothane. The advancing section 3114 may have bending stiffness and radial crush stiffness that are about 50% or less, and in some implementations, about 25% or about 15% or about 5% or less, corresponding values, than the proximal section 3118.

Support fibers 3142, as discussed elsewhere herein, extend through at least a distal portion of the length of the proximal section 3118. Illustratively, the support fibers 3142 may terminate distally at the proximal face of the marker band 3116 and extend axially radially outward from the tubular liner 3120 and radially inward from the support coil 3122. The fibers 3142 may extend substantially parallel to the longitudinal axis or may be angled into a loose spiral having 10 or 7 or 3 or 1 or less full turns around the catheter along the length of the spiral. The fibers may include a high tensile material, such as a multifilament yarn spun from a liquid crystal polymer, such as Vectran multifilament LCP fiber.

Depending on whether the catheter 3000 can be navigated distally enough to reach the target site, an intraluminal extension catheter, such as a tubular elastic extension section having a proximally extending control wire, may be inserted through the catheter 3000 from the proximal end of the catheter 3000. The extension section is inserted and advanced distally such that the distal end of the extension section reaches further distally beyond the distal end of the catheter 3000. The outer diameter of the extension section is smaller than the inner diameter of the catheter 3000. In this manner, the extension section can slide within the lumen of the catheter 3000.

The extension section incorporates the sidewall structure characteristics of the catheter 3000 described herein. The axial length of the tubular extension section may be less than about 50% of the length of the catheter 3000, and typically less than about 25%. The axial length of the tubular extension section will generally be at least about 10 cm, 15 cm, 20 cm, 25 cm, or more, but generally not more than about 70 cm, 50 cm, or 30 cm.

With reference to Figures 8A-8C, any of the catheters described herein may have one or more axially extending filaments 3242.

10A-10B, the beveled surface 3126 of the catheter of FIG. 7E has been further modified to a blunted beveled surface 4000 such that the leading edge tip (shown in FIG. 7E) has been removed. As shown in FIG. 10B, the catheter distal surface 4000 includes a first section 4012 that resides on a first plane transverse to the longitudinal axis of the tubular body at a first angle 4020 in the range of about 35 degrees to about 55 degrees, and a second section 4014 that resides on a second plane transverse to the longitudinal axis of the tubular body at a second angle 4010 in the range of about 55 degrees to about 90 degrees. The section 4016 shown in FIG. 10A of the distal surface 4000 shown in FIG. 7E has been removed. One result of the angle 4020 being less than 90 degrees and the blunted length 4014 is an elongation of the long axis of the distal port area, which increases the surface area of the port and may enhance clot aspiration or retention while minimizing the possibility of vessel wall damage.

Compared to the surface area of a circular port (angles 4020 and 4010 are both 90 degrees), the area of the angled blunted port is generally at least about 105% and not more than about 150%, in some implementations in the range of about 110% to about 125%, and in one example, about 115%. The degree of blunting can be defined by the ratio of the unblunted axial length 4022 measured from the trailing edge 4024 to the leading edge 4026 to the blunted axial length shown as section 4018.

As shown in FIG. 10A, a blunting ratio of 3/4 is shown. The blunted length 4016 of the tip 4000 may be 1-5 mm, 1-4 mm, 1-3 mm, 1-2 mm, 0.1-0.2 mm, 0.2-0.3 mm, 0.3-0.4 mm, 0.4-0.5 mm, 0.5-0.6 mm, 0.6-0.7 mm, 0.7-0.8 mm, 0.8-0.9 mm, 0.9-1.0 mm, 0.1-0.5 mm, 0.5-1.0 mm, less than 1 mm, greater than 1 mm, at least 2 mm, at least 3 mm, at least 4 mm, at least 5 mm, or any range or subrange therebetween of the entire catheter distal surface 4022. In some embodiments, the length 4016 of the distal surface 4000 is defined by a percentage of the outer diameter of the catheter, for example, the length 4016 may be equal to the length of 10%-500%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 100%-200%, 200%-300%, 300%-400%, 400%-500%, or any range or subrange therebetween, of the outer diameter of the catheter.

With reference to FIG. 10B, the angle 4020 of the first or beveled section of the distal surface 4000 may be 5-10 degrees, 10-15 degrees, 15-20 degrees, 20-25 degrees, 25-30 degrees, 30-35 degrees, 35-40 degrees, 40-45 degrees, 45-50 degrees, 50-55 degrees, 55-60 degrees, 60-65 degrees, 65-70 degrees, 70-75 degrees, 75-80 degrees, 80-85 degrees, 85-90 degrees, 90-95 degrees, or any range or sub-range therebetween. The angle 4020 of the first or beveled section of the distal surface 4000 may be at least 10 degrees, at least 15 degrees, at least 20 degrees, at least 25 degrees, at least 30 degrees, at least 35 degrees, at least 40 degrees, at least 45 degrees, at least 50 degrees, at least 55 degrees, at least 60 degrees, at least 65 degrees, at least 70 degrees, at least 75 degrees, at least 80 degrees, at least 85 degrees, at least 90 degrees, or at least 95 degrees. In some embodiments, the angle 4020 of the first or beveled section of the distal surface is equal to 0 to 30 degrees, 30 to 60 degrees, 60 to 90 degrees, or any range or subrange therebetween. In some embodiments, the angle 4020 is equal to 15 to 45 degrees, 45 to 75 degrees, 75 to 95 degrees, or any range or subrange therebetween. The angle 4010 of the second or blunted segment of the distal surface 4000 may be 55-60 degrees, 60-65 degrees, 65-70 degrees, 70-75 degrees, 75-80 degrees, 80-85 degrees, 85-90 degrees, or any range or subrange therebetween. The angle 4010 of the second or blunted segment of the distal surface 4000 may be at least 55 degrees, at least 60 degrees, at least 65 degrees, at least 70 degrees, at least 75 degrees, at least 80 degrees, at least 85 degrees, or at least 90 degrees. In some embodiments, the angle 4010 of the second or blunted segment of the distal surface 4000 is equal to 55-65 degrees, 65-75 degrees, 75-90 degrees, or any range or subrange therebetween.

式中、Δｚは先端部の全長４１３０であり；
ｍは、傾斜係数であり；
ｒは半径方向の位置であり；
そしてｒ_ｃはカテーテル半径である。
傾斜係数を変更することにより、波形の急峻さを調整することができる。 11A-11B, a sinusoidally shaped distal surface 4100 is shown that includes a first section or convex wave or shape or shovel or curve 4110 defined by a first radius of curvature, which transitions to a second section or concave wave or shape or shovel or curve 4120 defined by a second radius of curvature. Each curve 4110, 4120 may have a diameter ranging from, for example, 0.02 inches to 0.05 inches depending on the size of the catheter. Each curve 4110, 4120 is further defined by a radius of curvature 4112, 4114, respectively, as shown in FIG. 41B. In some embodiments, the first convex curve 4110 and the second concave curve 4120 each have the same or similar or substantially similar (+/- 5%) radii of curvature 4112, 4114. In other embodiments, the first convex curve 4110 and the second concave curve 4120 have different radii of curvature 4112, 4114, respectively. The 2D profile of the distal surface shape 4100 (e.g., when projected onto the radial plane shown in FIG. 11A) is given by the following equation:

where Δz is the total length of the tip 4130;
m is the slope coefficient;
r is the radial position;
and _rc is the catheter radius.
By changing the slope coefficient, the steepness of the waveform can be adjusted.

11A, the slope or angle of each curve 4110, 4120 can be defined by angles 4140 and 4150, respectively. For example, to calculate each angle 4140, 4150, an axis may be positioned at the transition point along the longitudinal center of the catheter between the first curve 4110 and the second curve 4120 such that the angles 4140, 4150 define the curve or shape of the distal surface 4100. In some embodiments, angle 4140 is between 0 and 5 degrees, between 5 and 10 degrees, between 10 and 15 degrees, between 15 and 20 degrees, between 20 and 25 degrees, between 25 and 30 degrees, between 30 and 35 degrees, between 35 and 40 degrees, between 40 and 45 degrees, between 45 and 50 degrees, between 50 and 55 degrees, between 55 and 60 degrees, between 60 and 65 degrees, between 65 and 70 degrees, between 70 and 75 degrees, between 75 and 80 degrees, between 80 and 85 degrees, between 85 and 90 degrees, or any range or sub-range therebetween. In some embodiments, angle 4140 is between 30 and 60 degrees, between 15 and 85 degrees, or any range or sub-range therebetween. In some embodiments, the angle 4150 is 0-5 degrees, 5-10 degrees, 10-15 degrees, 15-20 degrees, 20-25 degrees, 25-30 degrees, 30-35 degrees, 35-40 degrees, 40-45 degrees, 45-50 degrees, 50-55 degrees, 55-60 degrees, 60-65 degrees, 65-70 degrees, 70-75 degrees, 75-80 degrees, 80-85 degrees, 85-90 degrees, or any range or subrange therebetween. In some embodiments, the angle 4150 is 30-60 degrees, 15-85 degrees, or any range or subrange therebetween.

Referring to FIG. 12, a schematic diagram of a numerical simulation model is shown. A computational fluid dynamics (CFD) model was created to simulate the aspirating of a soft clot 4120 in a blood vessel 4210, surrounded by blood 4130, into a catheter 4140 with various shapes or angles 4150 on its distal surface.

Exemplary CFD model data is shown in Figures 13A-13B. Images of the numerical simulation of clot aspiration show the initial state 4300 in Figure 13A and the effective aspiration state 4310 in Figure 13B. The amount of clot material aspirated over time was measured for various shapes or angles 4150 of the distal face. The values for a circular (transverse) port (e.g., the one shown in Figure 3A) were used as a baseline or control to benchmark the success of the proposed profile. A particular shape or angle of the distal face was deemed more successful if it was able to aspirate more material than a circular port shape. A higher aspiration rate indicates less resistance to aspiration and less chance of complications during the aspiration-thrombectomy procedure.

With reference to FIG. 14, the percent increase in aspiration volume is shown as a function of distal surface angle. For example, distal surfaces exhibiting a 60 degree angle had the greatest increase in aspiration efficiency compared to surfaces with smaller angles (15 degrees to 45 degrees). Aspiration volume for surfaces with a 60 degree bevel increased by more than 60% over a circular surface, between 60-70% over a circular surface, or between 50-70% over a circular surface. A distal surface with a 45 degree bevel had an increase in aspiration volume of more than 40%, between 40-50%, between 30-60%, or more than 45% over a circular surface. A distal surface with a 30 degree bevel had an increase in aspiration volume of more than 20%, more than 25%, between 20-30%, or between 15-40% over a circular surface. Even a distal surface with a 15 degree angle showed a 10% improvement in aspiration volume over a circular surface.

Exemplary reasons for this improvement in aspiration efficiency as a function of tip angle are: (1) the surface area of the catheter opening in contact with the clot increases, which increases the force on the clot (pressure = force/area), and (2) the length of the clot that is captured over a distance (i.e., capture length) increases, smoothing the shape change of the clot as it flows from a larger vessel into a smaller catheter. The latter of these two design theories is supported by examination of the flow profile during aspiration experiments. With a more pronounced sinusoidal profile, the flow was more uniform and less turbulent as it entered the smaller catheter. As shown in Figure 14, as the face angle increases, the percent increase in aspiration volume increases, indicating that, overall, the face profile has a beveled result, resulting in a larger face opening, which increases aspiration efficiency.

Turning now to Figures 15A-15C, which show CFD velocity field profiles for various face angles (i.e., no angle, i.e., 0 degree, 30 degree angle, and 60 degree angle). As shown in Figure 15A, the circular face profile exhibited significant constriction of flow, thus increasing resistance to clot entrapment. In contrast, distal faces with angles of 30 degrees (Figure 15B) or 60 degrees (Figure 15C) dramatically increased clot entrapment, as shown in the respective plots. As shown in Figure 15C, the face with a 60 degree bevel angle exhibited a greater distance between adjacent contour lines and a leading edge 4500 of the velocity coefficient extending further into the modeled catheter body, as compared to the leading edge 4510 of the face with a 30 degree bevel angle.

16A-16B. FIG. 16A shows the capture length 4610 for a beveled surface 4600, and FIG. 16B shows the capture length 4620 for a blunted beveled surface 4650. In some embodiments, the length 4610 is equal to or substantially equal to the length 4620, while in other embodiments, the length 4610 is greater than, less than, or different from the length 4620. The capture length 4610 is determined by calculating the difference between the leading edge 4614 and the trailing edge 4612, where the leading edge and the trailing edge have been described in connection with FIG. 7E. Similarly, the capture length 4620 is determined by calculating the difference between the leading edge tip 4624 and the trailing edge tip 4622. In exemplary, non-limiting embodiments, the uptake length ranges from 0.25 mm to 4.5 mm; 0.5 mm to 4 mm, 0.5 mm to 2.5 mm, 3.5 mm to 4 mm, 2 mm to 2.5 mm, 1.5 mm to 2 mm, 1 mm to 1.5 mm, 0.5 mm to 1 mm, etc. The uptake length is directly related to the percent increase in aspirated volume over the circular surface control.

Figure 17 illustrates the percent increase in aspirated material for catheters with various distal surface profiles (i.e., beveled, blunted beveled, sinusoidal) as a function of uptake length. All proposed profiles showed improvement over the circular surface profile. The improvement ranged from substantially 10% to substantially 70%. In addition, the blunted beveled and sinusoidal surfaces performed just as well as the beveled surfaces at the same uptake length. This suggests that blunt or smooth catheters can perform just as well as sharp catheters as long as the uptake lengths are the same, similar, or substantially similar.

For example, when the uptake length of the beveled surface ranged from about 0.5 mm to about 4 mm, the percent increase in aspiration volume over the circular control increased from about 10% to about 70%. When the uptake length of the blunted beveled surface was about 1 mm to about 1.6 mm, or about 1 mm to about 1.75 mm, the percent increase in aspiration volume over the circular control increased from about 18% to about 38%. The sinusoidal surface demonstrated an increase in aspiration volume of about 35% over the circular control for uptake lengths of about 1.7 mm to about 1.7 mm.

18A-18B, an example of an outer jacket section layering pattern is illustrated for a progressively flexible catheter of the type discussed in connection with FIG. 1A or 7A, for example. The distal section 3038 may have a length in the range of about 1-3 cm and a durometer of about 35D or less than 30D. The adjacent proximal section 3036 may have a length in the range of about 4-6 cm and a durometer of about 35D or less than 30D. The adjacent proximal section 3034 may have a length in the range of about 4-6 cm and a durometer of about 35D or less. The adjacent proximal section 3032 may have a length in the range of about 1-3 cm and a durometer in the range of about 35D to about 45D (e.g., 40D). The adjacent proximal section 3030 may have a length in the range of about 1-3 cm and a durometer in the range of about 50D to about 60D (e.g., about 55D). The adjacent proximal section 3028 may have a length in the range of about 1-3 cm and a durometer in the range of about 35D to about 50D to about 60D (e.g., about 55D). The adjacent proximal section 3026 may have a length in the range of about 1-3 cm and a durometer of at least about 60D, typically less than about 75D.

The more proximal section may have a durometer of at least about 65D or 70D. The most distal two or three sections may comprise a material such as Tecothane, and the more proximal section may comprise PEBAX or other catheter jacket materials known in the art. At least three or five or seven or nine or more separate sections may be utilized, where the change in durometer between the highest and lowest along the length of the catheter shaft is at least about 10D, preferably at least about 20D, and in some implementations at least about 30D or 40D or more.

Catheter performance indicators include back-up support, trackability, pushability, kink resistance, etc. Back-up support refers to the ability of the catheter to remain in the anatomically correct position and provide a stable platform through which an intraluminal device may be advanced. Referring to FIG. 19, when a device is pushed through the catheter 3202, without sufficient back-up support within the catheter 3202, the distal portion 3204 of the catheter 3202 may escape, be pulled out, or back out of the blood vessel 3206 that branches off from the main vessel (e.g., the brachiocephalic artery 82, the common carotid artery 80, or the subclavian artery 84). Back-up support of the catheter 3202 may be improved by providing a proximal region with a high durometer or modulus and a distal region with a low durometer or modulus.

The durometer or modulus of the proximal region of the catheter 3202 may be improved by braided reinforcement. The region of the catheter with enhanced durometer or modulus may be located near the bifurcation of the aortic arch 1114, 1214 into the brachiocephalic artery 82, the common carotid artery 80, or the subclavian artery 84, or near other anatomical structures (i.e., bifurcation points) where a main vessel branches into one or more smaller vessels, creating a risk of catheter prolapse with poor backup support. For example, the region of the catheter with enhanced durometer or modulus may be located within about 0.5 cm, about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, or about 6 cm of the bifurcation point where a main vessel branches into one or more smaller vessels.

Trackability refers to the ability of a catheter to track further distally (e.g., to M1) than other catheters. For example, a catheter that can reach the cerebral division of the internal carotid artery (ICA) will have better trackability than a catheter that can reach the cavernous sinus or petrosal division of the ICA. Catheter trackability may be improved by using a catheter wall with a lower durometer or modulus of elasticity or by adding a coating (e.g., a hydrophilic coating) to at least a portion of the catheter wall. In one embodiment, the hydrophilic coating may be located along the most distal region of the catheter. The hydrophilic coating on the catheter may extend from about 1 cm, about 5 cm, about 10 cm, about 15 cm, or about 20 cm from the distal end of the catheter. The region with the lower durometer or modulus of elasticity may be located at the most distal region of the catheter. The region with the lower durometer or modulus of elasticity may extend from about 1 cm, about 5 cm, about 10 cm, about 15 cm, or about 20 cm from the distal end of the catheter.

Pushability refers to the stiffness of the catheter enough to push it through the anatomy without "buckling." The pushability of a catheter may be improved by increasing its durometer or modulus. It may also be improved by providing a proximal region with a high durometer or modulus and a distal region with a low durometer or modulus. A transition region of a catheter that changes durometer or modulus along its longitudinal length (e.g., a decrease in durometer or modulus from the proximal end to the distal end) may begin about 50%, 60%, 70%, 75%, 80% or more of the length of the catheter from its proximal end.

Kink resistance means that the catheter is less likely to kink. Additionally, if the catheter does kink, the kink resistance of the catheter helps it return to its original shape. Kink resistance is important in the distal section of the catheter, which is more prone to kinking than the proximal section. The kink resistance of a catheter may be improved by adding one or more NiTi coils (or coils at least a portion of which is Nitinol) to the catheter wall.

FIG. 20 illustrates a graph of the durometer or modulus of a catheter according to the present invention along the length of the catheter from the proximal end (x=0) to the distal end (x=1). A catheter according to one embodiment may have a durometer or modulus (E) that decreases as it approaches its distal end. The proximal end of the catheter has a higher durometer or modulus than the distal end of the catheter. A higher durometer or modulus near the proximal end provides better back-up support for the catheter. The durometer or modulus of the catheter is substantially constant along its length near the proximal end 3302 of the catheter. The durometer or modulus of the catheter then decreases near the distal end 3304 of the catheter. The durometer or modulus of the catheter may begin to decrease about 50%, 70%, 75%, 80%, or 90% of the length of the catheter from its proximal end (i.e., the transition region). The catheter may have a gradually decreasing durometer or modulus near its distal end, either by using a material with a smaller durometer or modulus near the distal end, or by having a catheter wall that is thinner there. The reduced durometer or modulus near the distal end provides the catheter with excellent trackability.

Figure 21 describes the flexibility test profile of a catheter according to the present invention compared to a conventional catheter. Catheter flexibility was measured by a three-point bending test using a span of 1 inch and a displacement of 2 mm. In other words, Figure 21 describes the force (i.e., bending load) required to vertically displace a 1 inch long catheter section 2 mm with respect to the distance from the stress release (i.e., the proximal end of the catheter) to the point of force application. The elastic modulus of the catheter remains substantially constant along its length near the proximal end and then gradually decreases near the distal end.

Catheters according to the invention have a bending load that is substantially constant along the longitudinal length near the proximal end and that decreases rapidly near the distal end. For a catheter having a length of about 125 cm, the catheter may have a bending load of about 1.0 lbF, about 1.5 lbF, about 2.0 lbF, about 2.5 lbF, about 3.0 lbF, or about 3.5 lbF or more at about 85 cm from the proximal end. The catheter may have a bending load of about 2.5 lbF, about 2.0 lbF, about 1.5 lbF, about 1.0 lbF, or about 0.5 lbF or less at about 95 cm from the proximal end. The catheter may have a bending load of about 1.5 lbF, about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.25 lbF, or about 0.1 lbF or less at about 105 cm from the proximal end. The catheter may have a bending load of about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.4 lbF, about 0.3 lbF, about 0.2 lbF, or about 0.1 lbF or less at about 115 cm from the proximal end. For catheters having different lengths, the above dimensions may be scaled as a percentage of the length of the catheter from the distal end of the catheter.

In a particular implementation constructed in accordance with FIG. 5, the bending load is less than about 3.0 or 3.25 lbF at 65 cm from the proximal end and averages greater than about 2.25 or 2.5 lbF at 65 cm to 85 cm from the proximal end. The bending load drops to about 1.0 or less, preferably about 0.5 lbF or less, at about 95 cm from the proximal end. This provides enhanced backup support in the aorta while maintaining enhanced compliance to the distal vasculature.

In other embodiments, the catheter may have a bending load of about 1.0 lbF, about 1.5 lbF, about 2.0 lbF, about 2.5 lbF, about 3.0 lbF, or about 3.5 lbF or more at about 60 cm from the proximal end. The catheter may have a bending load of about 2.0 lbF, about 1.5 lbF, about 1.0 lbF, or about 0.5 lbF or less at about 70 cm from the proximal end. The catheter may have a bending load of about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.4 lbF, about 0.3 lbF, about 0.2 lbF, or about 0.1 lbF or less at about 80 cm from the proximal end. The catheter may have a bending load of about 1.0 lbF, about 0.75 lbF, about 0.5 lbF, about 0.4 lbF, about 0.3 lbF, about 0.2 lbF, or about 0.1 lbF or less at about 90 cm from the proximal end.

The catheter may have a transition region that changes bending load by about 1.0 lbF, about 1.5 lbF, about 2.0 lbF, about 2.5 lbF, about 3.0 lbF, or about 3.5 lbF or more. The longitudinal length of the transition region may be about 20 cm, about 15 cm, about 10 cm, about 5 cm, about 3 cm, or about 1 cm or less.

Compared to Neuron Max (Penumbra, Inc.) 3402, catheters according to the present invention (e.g., 3404, 3406, 3408, 3410) have a similar modulus near their proximal ends. In this way, catheters according to the present invention provide backup support equivalent to Neuron Max. In addition, these catheters have a modulus that drops off more rapidly near the transition region (between the proximal and distal ends) than that of Neuron Max.

Compared to the Ace 68 Catheter (Penumbra) 3412, the Ace 64 Catheter (Penumbra) 3414, the Benchmark 71 Catheter (Penumbra) 3416, and the Sofia Plus (MicroVention) 3418, the catheters according to the invention have a greater modulus near their proximal end and a comparable modulus near their distal end. In this way, the catheters according to the invention may provide better back-up support with comparable compliance compared to conventional catheters. The catheters according to the invention may achieve this modulus profile even when their inner diameter (and therefore lumen volume) is equal to or greater than the inner diameters of the Ace 68, Ace 64, Benchmark 71, and Sofia Plus, which range from 0.064 inches to 0.071 inches.

Suitable access for the catheter of the present invention can be achieved using conventional techniques through an incision in a peripheral artery, such as the right femoral artery, left femoral artery, right radial artery, left radial artery, right brachial artery, left brachial artery, right axillary artery, left axillary artery, right subclavian artery, or left subclavian artery. In emergency situations, an incision can also be made in the right or left carotid artery.

Avoiding a tight fit between the guidewire and the inner diameter of the guidewire lumen enhances the slidability of the catheter over the guidewire. In ultra-small diameter catheter designs, it may be desirable to coat the outer surface of the guidewire and/or the inner surface of the wall defining the GW lumen with a lubricious coating to minimize friction as the catheter 10 moves axially relative to the guidewire. Various coatings may be utilized, e.g., Paralene, Teflon, silicone, polyimide-polytetrafluoroethylene composites, or others known in the art as appropriate for the guidewire or inner tubular wall.

Aspiration catheters of the present invention adapted for intracranial applications generally have an overall length ranging from 60 cm to 250 cm, usually from about 135 cm to about 175 cm. The length of the proximal section 33 will typically be from 20 cm to 220 cm, more typically from 100 cm to 120 cm. The length of the distal section 34 will typically be from 10 cm to about 60 cm, usually from about 25 cm to about 40 cm.

The catheters of the present invention may comprise any of a variety of biocompatible polymeric resins that have suitable properties when formed into a tubular catheter body section. Exemplary materials include polyvinyl chloride, polyethers, polyamides, polyethylene, polyurethanes, copolymers thereof, and the like. Optionally, the catheter body may be reinforced with a metallic or polymeric braid or other conventional reinforcing layer.

The catheter body may further include other components, such as radiopaque fillers; colorants; reinforcing materials; reinforcing layers, such as braided or helical reinforcing components; and the like. In particular, the proximal body section may be reinforced to increase its column strength and torquability, preferably while limiting its wall thickness and outer diameter.

In one aspect of the disclosure, the system for aspirating vascular occlusion further includes a controller that applies a pulsatile vacuum cycle to the central lumen. In another aspect of the disclosure, the system for aspirating vascular occlusion further includes a rotating hemostatic valve coupled to the proximal end of the tubular body, the rotating hemostatic valve including: at least one main lumen along its longitudinal length through which the proximal portion of the clot grasping device is configured to pass; and an aspiration lumen branching from the main lumen and including a vacuum port.

In accordance with another aspect, a method is provided for aspirating material from at least as distal to the cerebral segment of the internal carotid artery through a femoral access site, comprising: advancing a guidewire from a femoral access site to a location at least as distal to the cerebral segment of the internal carotid artery, the guidewire having a proximal section having a diameter of at least about 0.030 inches and a distal section having a length of no more than about 25 cm and a diameter of no more than about 0.020 inches; and following an aspiration catheter directly over the guidewire and at least as distal to the cavernous sinus segment, the aspiration catheter having a distal end and a central lumen at the distal end having a diameter of at least about 0.080 inches and a beveled distal tip. In one aspect of the disclosure, the diameter of the proximal section of the guidewire is about 0.038 inches and the diameter of the distal section is about 0.016 inches.

With the distal end positioned at least as far distal to the cavernous sinus segment of the middle cerebral artery, a vacuum is applied to the lumen to draw the thrombus into the lumen; the thrombus is mechanically engaged to facilitate attachment to and potentially entry into the lumen.

The mechanically engaging step may include advancing the clot grasping device to or beyond the distal end of the tubular body. The method of engaging the vascular occlusion may include manually rotating the clot grasping device within the tubular body to engage the clot.

In yet another aspect of the present disclosure, the method of aspirating vascular occlusion further includes providing sufficient backup support to the combination access and aspiration catheter to resist prolapse of the catheter into the aorta. To provide backup support to the combination access and aspiration catheter, the combination access and aspiration catheter may be advanced over a guidewire having a distal end positioned at least as distal to the cavernous sinus segment of the internal carotid artery, the guidewire having a diameter at the point where it enters the brachiocephalic artery of at least about 0.030 inches. To provide backup support to the combination access and aspiration catheter, the combination access and aspiration catheter may be advanced over a guidewire having a distal end positioned at least as distal to the cavernous sinus segment of the internal carotid artery, the guidewire having a diameter at the point where it enters the brachiocephalic artery of at least about 0.030 inches, e.g., about 0.035 inches, or 0.038 inches.

The guidewire may be navigable to at least the cerebral division of the internal carotid artery by having a distal section having a diameter of about 0.020 inches or less. The guidewire may be navigable to at least the cerebral division of the internal carotid artery by having a distal section having a diameter of about 0.016 inches. The diameter of the proximal section of the guidewire may be about 0.038 inches, and the diameter of the distal section may be about 0.016 inches.

The present invention has been described in terms of preferred embodiments, but may be incorporated into other embodiments by one of ordinary skill in the art in light of the disclosure herein. Accordingly, the scope of the present invention is not intended to be limited by the specific embodiments disclosed herein, but rather is intended to be defined by the full scope of the following claims.

A system for removing embolic material from an intravascular site,

An elongated, flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

An axial restraint device carried by the sidewall and exposed to the lumen;

A rotatable core wire that is extendable through the lumen and has a proximal end and a distal end;

A restricting device carried by the core wire and having a bearing surface that rotatably engages the restraining device;

a clot-grasping tip on the distal end of the core wire; and

The limiting device and the restraining device are configured to permit rotation of the core wire but limit distal advancement of the tip to no more than about 6 mm beyond the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the limiting device and the restraining device are configured to permit rotation of the core wire but limit distal advancement of the tip to no more than about 3 mm beyond the distal end of the tubular body.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the clot grasping tip includes a helical thread configuration.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the limiting device and restraining device are configured to permit rotation of the core wire but limit distal advancement of the tip beyond the distal end of the tubular body to exposure of the threaded structure between about 1 and 3 full rotations.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the axial restraint device includes a proximally-facing bearing surface.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the axial restraint device includes a protrusion extending radially inward.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the axial restraint device includes an annular flange.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the restriction device includes a distally facing bearing surface.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the restriction device includes a protrusion extending radially outward.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the radially outwardly extending protrusion is configured to be in sliding contact with the restraining device.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the proximal bearing surface on the axial restraint device is within about 30 cm of the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the proximal bearing surface is within a range of about 4 cm to 12 cm from the distal end of the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the helical thread has a maximum outer diameter that is no greater than about 90% of the inner diameter of the lumen and leaves an annular flow path between the tip and the inner surface of the sidewall.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the helical thread form has a blunted outer edge.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the restriction device is positioned within about the most distal 25% of the length of the core wire.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the core wire is removably positionable within the tubular body.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, further comprising a handle configured to manually rotate the core wire.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the helical thread form extends through no more than about 8 full rotations.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the helical thread form has an outer diameter that increases proximally from a first diameter near the distal tip to a second maximum outer diameter, and then decreases proximally from the maximum outer diameter to a third diameter.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the inner diameter of the tubular body adjacent the clot gripping tip is at least about 0.015 inches greater than the maximum outer diameter of the tip.

A torque transmission system that rotates and orients the distal end of a catheter,

An elongated, flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

a first engagement surface carried by the sidewall and exposed to the lumen;

A torque wire that is extendable through the lumen and has a proximal end and a distal end;

and a second engagement surface carried by the torque wire;

Distal advancement of the torque wire brings the second engagement surface into rotational coupling engagement with the first engagement surface, such that rotation of the torque wire in at least a first direction causes rotation of the distal end of the catheter.

A torque transmission system as disclosed in any embodiment herein, wherein the first engagement surface includes at least one inclined surface.

A torque transmission system as disclosed in any embodiment herein, wherein the first engagement surface is carried by a protrusion extending radially inward.

A torque transmission system as disclosed in any embodiment herein, wherein the protrusion includes a ring positioned within the lumen.

A torque transmission system as disclosed in any embodiment herein, wherein the second engagement surface includes a distally facing surface.

A torque transmission system as disclosed in any embodiment herein, wherein the distally facing surface includes at least one beveled surface.

A torque transmission system that rotates and orients the distal end of a catheter,

An elongated, flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

A first connector on the side wall exposed to the lumen;

A torque wire that is extendable through the lumen and has a proximal end and a distal end;

and a second, complementary connector carried by the torque wire;

The system allows the distal end of the catheter to rotate in response to rotation of the torque wire by coupling the first and second connectors.

A torque transmission system as disclosed in any embodiment herein, wherein the first connector includes at least one tooth having an oblique angle.

A torque transmission system as disclosed in any embodiment herein, wherein the first connector includes a protrusion extending radially inward.

A torque transmission system as disclosed in any embodiment herein, wherein the protrusion includes a ring positioned within the lumen.

A torque transmission system as disclosed in any embodiment herein, wherein the ring includes at least two proximally extending, obliquely angled teeth.

A torque transmission system as disclosed in any embodiment herein, wherein the second connector includes a distally facing surface carried by the torque wire.

A torque transmission system as disclosed in any embodiment herein, wherein the distally facing surface includes at least one beveled surface.

A torque transmission system as disclosed in any embodiment herein, wherein the second connector is movable radially outward.

A torque transmission system as disclosed in any embodiment herein, wherein the second connector includes an inflatable balloon and the first connector includes a surface on the sidewall.

A torque transmission system as disclosed in any embodiment herein, wherein the first connector includes an axially extending elongated groove sidewall configured to receive a protrusion on the torque wire.

A method for rotationally orienting a catheter,

Advancing a catheter having a central lumen and a distal end to a site within a body cavity;

Advancing a torque wire into the lumen;

Engaging a first connector of the torque wire with a second connector on the catheter;

and rotating the torque wire to cause rotation of the distal end of the catheter.

A system for removing embolic material from an intravascular site,

An elongated, flexible tubular body having a proximal end, a distal end, and a tubular sidewall defining at least one lumen extending axially therethrough;

a first engagement surface carried by the sidewall and exposed to the lumen;

A rotatable tap wire that is extendable through the lumen and has a proximal end and a distal end;

and a second engagement surface carried by the tap wire;

Distal advancement of the tap wire causes the second engagement surface to contact the first engagement surface, transferring momentum from the tap wire to the distal end of the tubular body.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the first engagement surface includes a proximally-facing surface.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the first engagement surface is carried by a radially inwardly extending protrusion.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the first engagement surface includes an annular flange.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the second engagement surface includes a distally facing surface.

A system for removing embolic material from an intravascular site, as disclosed in any embodiment herein, wherein the distally facing surface is the distal end of the tap wire.

A system for removing embolic material from an intravascular site as disclosed in any embodiment herein, wherein the distally facing surface is on a hammerhead carried by the wire.

A system for facilitating distal advancement of a catheter,

An elongated, flexible tubular body having a proximal end, a distal end, and a lumen extending therethrough;

A distal restraint device within the lumen;

A tap wire axially movably positionable through the lumen, the tap wire having a distal stop thereon;

A system in which distal movement of the distal stopper through the lumen is limited by the distal restraint device.

A system for facilitating distal advancement of a catheter as disclosed in any embodiment herein, wherein the distal restraint device includes a ring.

A system for facilitating distal advancement of a catheter as disclosed in any embodiment herein, wherein the tubular body terminates in an oblique plane.

A neurovascular catheter having a non-traumatic navigation tip,

An elongated flexible tubular body having a proximal end, a distal end, and a sidewall defining a central lumen,

The distal zone of the tubular body is:

A tubular inner liner;

A helical coil surrounding the inner liner and having a distal end;

a tubular jacket surrounding the helical coil and extending distally beyond the distal end of the helical coil and terminating at the distal surface of the catheter;

A tubular radiopaque marker embedded within the tubular jacket between the distal end of the coil and the distal surface,

A catheter, the distal surface of which includes a first section that resides on a first plane that intersects the longitudinal axis of the tubular body at a first angle in the range of about 35 degrees to about 55 degrees, and a second section that resides on a second plane that intersects the longitudinal axis of the tubular body at a second angle in the range of about 55 degrees to about 90 degrees.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the marker has a proximal surface that is approximately perpendicular to the longitudinal axis and a distal surface that resides in a plane that intersects the longitudinal axis at an angle within a range of about 55 degrees to about 65 degrees.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the distal surface defines a leading edge of the tubular body extending distally from a trailing edge of the tubular body, the leading edge and the trailing edge being spaced apart from each other by approximately 180 degrees about the longitudinal axis.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, in which the forward advancement section of the tubular body extends distally beyond the marker band.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the advancement section has an axial length on the leading edge of the tubular body within a range of about 0.1 mm to about 5 mm.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the axial length of the advancing section on the leading edge of the tubular body is greater than the length of the advancing section on the trailing edge of the tubular body.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the axial length of the marker band on the leading edge of the tubular body is at least about 20% longer than the axial length of the marker band on the trailing edge of the tubular body.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the axial length of the marker band on the leading edge of the tubular body is within the range of about 1 mm to about 5 mm.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the marker band includes at least one axial slit.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the tubular liner is formed by dip coating a removable mandrel.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the tubular liner comprises PTFE.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, further comprising a tie layer between the inner liner and the helical coil.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the bonding layer has a wall thickness of about 0.005 inches or less.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the tie layer extends along at least the most distal 20 cm of the flexible body.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the coil comprises nitinol.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the nitinol comprises an austenitic state at body temperature.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the outer jacket is formed from at least five individual axially adjacent tubular sections.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the outer jacket is formed from at least nine individual axially adjacent tubular sections.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the difference in durometer between the proximal and distal tubular sections is at least about 20D.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the difference in durometer between the proximal and distal tubular sections is at least about 30D.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, further comprising a tension support that increases tension resistance of the distal zone.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the tension support comprises an axially extending filament.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the axially extending filament is supported between the inner liner and the helical coil.

A neurovascular catheter having an atraumatic navigation tip as disclosed in any embodiment herein, wherein the axially extending filament increases the tensile strength of the tubular body to at least about 2 pounds.

Claims (14)

1. A system for removing embolic material from an intravascular site, comprising:
an elongated, flexible tubular body having a proximal end, a distal end and a tubular sidewall defining at least one lumen extending axially therethrough;
an axial restraint device including a proximally-facing bearing surface;
a rotatable core wire extendable through said lumen and having a proximal end and a distal end;
a restriction device carried by the core wire and having a distal-facing bearing surface configured to abut the proximally-facing bearing surface of the restraining device;
an engagement tip on the distal end of the core wire, the engagement tip including a helical thread form;
the limiting device and the restraining device are configured to permit rotation of the core wire, and the limiting device and the restraining device are configured such that when the distal end of the core wire is approximately aligned with the distal end of the tubular body, the distal-facing bearing surface of the limiting device and the proximal-facing bearing surface of the restraining device are separated by an axial gap. The system of claim 1, wherein the limiting device and the restraining device are configured to permit rotation of the core wire but limit distal advancement of the engagement tip to no more than about 3 mm beyond the distal end of the tubular body. The system of claim 1, wherein the limiting device and the restraining device are configured to permit rotation of the core wire but limit distal advancement of the engagement tip beyond the distal end of the tubular body to exposure of the thread form between about 1 and 3 full revolutions. The system of claim 1, wherein the helical thread form has a maximum outer diameter that is no greater than about 90% of the inner diameter of the lumen, leaving an annular flow passage between the engagement tip and the inner surface of the sidewall. The system of claim 1, wherein the helical thread form has a blunt outer edge. The system of claim 1, wherein the core wire is removably positionable within the tubular body. The system of claim 1, further comprising a handle configured to manually rotate the core wire. The system of claim 1, wherein the helical thread form extends through no more than about 8 full revolutions. The system of claim 1, wherein the helical thread form has an outer diameter that increases proximally from a first diameter near the distal tip to a second maximum outer diameter, and then decreases proximally from the maximum outer diameter to a third diameter. The system of claim 1, wherein the inner diameter of the tubular body adjacent the engagement tip is at least about 0.015 inches greater than the maximum outer diameter of the engagement tip. The system of claim 1, further comprising a tubular radiopaque marker embedded in the flexible tubular body. The system of claim 1, wherein the distal end of the tubular body includes a beveled surface. The system of claim 1 , wherein at least a portion of the engagement tip is located outside of the tubular body when the distally facing bearing surface abuts the proximally facing bearing surface. The system of claim 1, wherein the axial restraint device is configured to be located on a proximal hub, and the proximal hub is configured to be located on the proximal end of the tubular body.

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