JP7326419B2 - Abrasive elements for rotary atherectomy systems - Google Patents

Description

[0001] The present disclosure is generally directed to systems, devices and methods for atherectomy. More particularly, the present disclosure is directed to novel shapes for abrasive elements used in atherectomy procedures.

[0002] Atherosclerosis is the leading cause of coronary heart disease. Atherosclerosis occurs when lipids, cholesterol and/or other substances accumulate within the walls of blood vessels to form hard structures and/or atherosclerotic lesions called plaques. Over time, these plaques and/or lesions can increase in size such that the blood vessel becomes clogged and/or completely occluded.

[0003] Rotary atherectomy, for example, is a technique used to abrade calcified arterial lesions. Rotary atherectomy devices and rotary atherectomy procedures may also be referred to as rotary angioplasty devices and/or rotary angioplasty procedures. One type of rotational atherectomy device is known as an orbital atherectomy device, for example US2014/0081298 and US2014/0316449. It is described in documents, etc.

[0004] Rotary atherectomy devices may include an abrasive element attached to a proximal portion of a rotatable flexible drive shaft. A rotatable flexible drive shaft may be carried over a guidewire and/or through a sheath to a desired location. Abrasive elements may be referred to as burrs, crowns and/or beads. The drive shaft can be rotated at high speeds (eg, between 20,000 and 160,000 rpm). As the abrasive element rotates, it can be advanced over the stenotic lesion or plaque to contact the obstructing tissue and/or plaque. In this way, the abrasive element scrapes the surface of the lesion and abrades the lesion into very small particles. These small particles can be removed from the site by the bloodstream.

[0005] The devices, systems and methods of this disclosure have several features, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the invention set forth below as represented by the claims, its superior features will now be briefly discussed. After considering this discussion, and particularly after reading the Detailed Description section, how the features of the present disclosure provide several advantages over other rotary atherectomy systems. Some will understand.

[0006] The present disclosure is directed to novel bead shapes that can provide improved abrading efficiency in atherectomy procedures. One embodiment is a high speed rotary atherectomy device for opening a stenosis in an artery having a lumen extending therethrough. The device may comprise a flexible elongated rotatable drive shaft. The device can also include a guidewire having a maximum diameter that is less than the diameter of the lumen. In such embodiments, the drive shaft can be advanceable over the guidewire. Abrasive elements may be disposed on the drive shaft. The polishing element can have a first center of mass that is radially offset from the center of mass of the drive shaft. The polishing element can have a second center of mass that is second radially offset from the center of mass of the drive shaft. The second center of mass may be positioned proximal to the first center of mass. The second radial direction may be primarily the opposite of the first radial direction. In some aspects, the polishing elements are eccentrically shaped.

[0007] The polishing element can have a proximal end and a distal end. The polishing element can have a total center of mass located between the proximal and distal ends. In some embodiments, the total center of mass can be located at a midpoint between the proximal and distal ends. The distal end can have a center of mass that is first radially offset from the center of mass of the drive shaft. The proximal end can have a second radially offset center of mass from the center of mass of the drive shaft. The second radial direction may be opposite to the first radial direction. In some aspects, the sharpening element comprises a waist positioned between the proximal and distal ends of the sharpening element. In some aspects, at least a portion of the outwardly facing surface is roughened, ie rough compared to the external surface of the drive shaft. In some aspects, the center of mass comprises a heavier material than the rest of the polishing element. In other words, the center of mass of the polishing element can include material having a density greater than the density of the material in the remainder of the polishing element. In some aspects, the sharpening element is positioned on the drive shaft such that the sharpening element is allowed to move radially relative to the drive shaft. For one embodiment, it would not be unthinkable for the abrasive element to comprise a distal portion, a central portion and a proximal portion. In such embodiments, each of these portions can have a radially offset center of mass, even if the radial directions are more or less the same for the distal and proximal portions. good. For the central portion, this offset may be in a direction that is approximately the opposite of that offset for the distal and proximal portions. The combined center of mass of the distal and proximal portions can be proximal or distal to the center of mass of the central portion when viewed in the longitudinal direction of the drive shaft. However, it is also conceivable that the combined centers of mass of the distal and proximal portions coincide with the center of mass of the central portion with respect to longitudinal position along the drive axis. The center of mass may be balanced or slightly unbalanced with respect to the drive shaft.

[0008] Another embodiment is a high speed rotary atherectomy device for opening a stenosis in an artery having a lumen extending therethrough. The device can comprise a flexible elongated rotatable drive shaft sized and shaped for insertion into the lumen. A device can also comprise a body. The body can have a radially expandable structure at a location between its distal and proximal ends. At least two abrasive elements may be disposed on the outer surface of the body and may be distributed around the radially expandable structure such that when the drive shaft is rotated, at least two abrasive elements are applied. The elements are pulled apart from each other to radially increase the dimension of the radially expandable structure therebetween. The body can have a slot extending through the side of the body at a location between its distal and proximal ends. The proximal and distal ends may be coupled to a flexible elongated rotatable drive shaft. The body and drive shaft can be advanceable over the guidewire. The body can comprise an elongated tube. Abrasive elements may be positioned on either side of the slot. When the drive shaft is rotated, the at least two polishing elements can be pulled away from each other to increase the width of the slot therebetween. In some aspects, the polishing element and the body are formed from different materials, ie, the polishing element can be formed from a different material than the material from which the body is formed. In some aspects, the at least two abrasive elements are positioned at different longitudinal locations along the body. In some embodiments, the rod extends from the proximal end of the slot to the distal end of the slot. The abrasive element can have a rough outer surface compared to the outer surface of the drive shaft. It would not be unthinkable that an embodiment could comprise three or more polishing elements. These may be evenly distributed around the radially expandable structure. The centers of mass may be balanced with respect to the drive shaft, or may be slightly unbalanced from each other.

[0009] Another embodiment includes a method of ablating a lesion in a blood vessel. The method may comprise advancing a guidewire through the vessel. A sheath may be advanced over the guidewire. The sheath can have a proximal end, a distal end, and a lumen extending therethrough. The sheath can comprise an introducer sheath. In aspects, the sheath comprises a catheter having a lumen extending therethrough. The method can also include advancing a flexible drive shaft over the guidewire and through the sheath. The drive shaft can have a proximal end, a distal end, and an abrasive element attached to the distal end. The polishing element can have a first diameter. The method can also include advancing the polishing element out of the distal end of the sheath and increasing the first diameter of the polishing element by rotating the drive shaft. The method can also comprise excising the lesion. In some aspects, the polishing element is constrained to a second diameter less than the first diameter as the polishing element is advanced through the sheath. This diameter may be the effective diameter.

[0010] These and other features, aspects, and advantages of the invention disclosed herein provide illustrations of particular embodiments that are intended to illustrate the invention and are not intended to be limiting thereof. Reference is made below. Additionally, like reference numbers are used throughout the figures to denote like components of the illustrated embodiments. Below is a brief description of each of the figures.

[0011] FIG. 1 is a schematic, perspective view of an atherectomy system that may be used with the abrasive elements disclosed herein, the atherectomy system may include a drive system coupled to a drive shaft; Abrasive elements can be coupled to the distal portion of the drive shaft. [0012] FIG. 1A is an enlarged perspective view of an abrasive element coupled to the distal portion of the drive shaft shown in FIG. 1; [0013] Fig. 2 is an enlarged perspective view of the polishing element of Figs. 1 and 1A with the drive shaft removed; [0014] Fig. 3 is a side view of the polishing element of Fig. 2; [0015] Fig. 3 is a top view of the polishing element of Fig. 2; [0016] Fig. 5 is a cross-sectional view of the polishing element of Fig. 4 along line 5-5; [0017] Fig. 4 is a front view of the polishing element of Fig. 3; [0018] Fig. 4 is a rear view of the polishing element of Fig. 3; [0019] Fig. 3 is a schematic cross-sectional view of the polishing element of Fig. 2 coupled to the drive shaft and biased against the inner wall of the sheath; [0020] FIG. 8B is a cross-sectional view taken about line 8B-8B of FIG. 8A; [0021] Fig. 8A is the same view as in Fig. 8A, except that the polishing element has been removed from the sheath and returned to the unbiased position; [0022] FIG. 8D is a cross-sectional view taken about line 8D-8D in FIG. 8C; [0023] FIG. 8B is the same view as FIG. 8A, except that the sharpening element is alternatively coupled to the drive shaft, and as shown, the sharpening element is biased against the inner wall of the sheath; there is [0024] FIG. 8F is a cross-sectional view taken about line 8F-8F of FIG. 8E; [0025] Fig. 8E is the same view as in Fig. 8E, except that the polishing element has been removed from the sheath and returned to the unbiased position; [0026] FIG. 8H is a cross-sectional view taken about line 8H-8H of FIG. 8G; [0027] Fig. 8G is the same view as Fig. 8G when the polishing elements are rotated at a high speed, and as shown, at least a portion of the polishing elements can move relative to the drive shaft; [0028] FIG. 8J is a cross-sectional view taken about line 8J-8J of FIG. 8I; [0029] FIG. 4 is a schematic cross-sectional view of a blood vessel illustrating exemplary operation of the abrasive elements disclosed herein. [0030] FIG. 4 is a schematic side view of an abrading element according to another embodiment, similar to the abrading element of FIG. 2, but without an angled internal lumen extending therethrough; [0031] FIG. 10B is the same view as FIG. 10A, except that the sharpening element is shown biased against the inner wall of the sheath; [0032] Fig. 10 is a perspective view of a polishing element according to another embodiment, as shown, the polishing element comprising a slotted tube and two polishing projections located on the outer surface of the tube and on opposite sides of the slot; , provided. [0033] Fig. 12 is an exploded view of the polishing element of Fig. 11; [0034] Fig. 13 is a perspective view of the slotted tube of Fig. 12; [0035] Fig. 13 is a side view of the slotted tube of Fig. 12; [0036] Fig. 13 is a top view of the slotted tube of Fig. 12; [0037] Fig. 15 is a front view of the slotted tube of Fig. 14; [0038] Fig. 13 is a perspective view of one of the polishing projections of Fig. 12; [0039] Fig. 18 is a top view of the polishing projection of Fig. 17; [0040] Fig. 18 is a bottom view of the polishing projection of Fig. 17; [0041] Fig. 18 is a side view of the polishing projection of Fig. 17; [0042] Fig. 18 is a front view of the polishing projection of Fig. 17; [0043] Fig. 12 is a side view of the polishing element of Fig. 11; [0044] Fig. 12 is a top view of the polishing element of Fig. 11; [0045] Fig. 12 is a cross-sectional view of the polishing element of Fig. 11; [0046] Same as FIG. 22, showing the polishing element in an unrestrained state. [0047] Fig. 12 is a side view of the polishing element of Fig. 11 positioned within the sheath and in a restrained state; [0048] FIG. 12 is a side view of the polishing element of FIG. 11 when the polishing element is rotated at a high speed, as shown, the polishing projections opening the slots when the polishing element is rotated at a high speed; [0049] Fig. 28 is a cross-sectional view of Fig. 26 taken about line 28-28; [0050] Fig. 29 is a cross-sectional view of Fig. 25 taken about line 29-29; [0051] Fig. 28 is a cross-sectional view of Fig. 27 taken about line 30-30; [0052] Fig. 12 is a perspective view of a sharpening element according to another embodiment, which is similar to the embodiment of Fig. 11, except that the two sharpening projections at least partially overlap the slots; [0053] Fig. 32 is a side view of the polishing element of Fig. 31; [0054] Fig. 32 is a top view of the polishing element of Fig. 31; [0055] Fig. 34 is a cross-sectional view of the polishing element of Fig. 32 taken about line 34-34; [0056] Fig. 32 is a side view of the polishing element of Fig. 31 positioned within a sheath; [0057] Fig. 35B is a cross-sectional view of Fig. 35A taken about line 35B-35B; [0058] FIG. 32 is a side view of the polishing element of FIG. 31 as the polishing element is rotated at high speed; Figure 36B is a cross-sectional view of Figure 36A taken about line 36B-36B; [0059] Fig. 12 is a perspective view of a polishing element according to another embodiment, which is similar to that of Fig. 11 except that the rods are positioned over slots within the slotted tube, this embodiment , may be referred to as a double-slotted embodiment. Although not shown, a double-slotted version of the device of FIG. 31 is also contemplated. [0060] Fig. 38 is an exploded view of the polishing element of Fig. 37; [0061] Fig. 39 is a perspective view of the double slotted tube of Fig. 38; [0062] Fig. 39 is a side view of the double slotted tube of Fig. 38; [0063] Fig. 39 is a top view of the double slotted tube of Fig. 38; [0064] Fig. 41 is a front view of the double slotted tube of Fig. 40; [0065] FIG. 38 is a side view of the polishing element of FIG. 37, showing the polishing element in an unrestrained state; [0066] Fig. 38 is a side view of the polishing element of Fig. 37 positioned within a sheath in a restrained state; [0067] Fig. 38 is a side view of the polishing element of Fig. 37 as the polishing element is rotated at a high speed; [0068] Fig. 46 is a cross-sectional view of Fig. 44 taken about line 46-46; [0069] Fig. 47 is a cross-sectional view of Fig. 43 taken about line 47-47; [0070] Fig. 48 is a cross-sectional view of Fig. 45 taken about line 48-48; [0071] FIG. 49 is a perspective view of an abrasive element according to another embodiment, the embodiment of FIG. 49 being similar to the embodiment of FIG. [0072] Fig. 50 is a side view of the polishing element of Fig. 49; [0073] Fig. 51 is a top view of the polishing element of Fig. 50; [0074] Fig. 52 is a cross-sectional view of the polishing element of Fig. 50 taken about line 52-52; [0075] FIG. 53 is a perspective view of an abrasive element according to a different embodiment, the embodiment of FIG. 53 being similar to the embodiment of FIG. 49 except that the abrasive projections are offset from one another along the longitudinal axis; . [0076] Fig. 54 is a side view of the polishing element of Fig. 53; [0077] Fig. 55 is a top view of the polishing element of Fig. 54; [0078] Fig. 55 is an axial view of the polishing element of Fig. 54;

[0079] The following descriptions and examples illustrate preferred embodiments of the rotational atherectomy devices of the present invention disclosed in the context of use in an atherectomy procedure. More particularly, these embodiments relate to rotational atherectomy devices and related techniques used, for example, to ablate calcified lesions in blood vessels.

[0080] The following description and accompanying drawings describing and showing preferred embodiments are made to demonstrate some possible configurations. These configurations can be incorporated into an atherectomy device and/or system comprising the various aspects and features disclosed. Those skilled in the art will appreciate that the disclosed aspects and features are not limited to any particular atherectomy system or device, which may include one or more of the aspects and features of the invention disclosed herein. you will understand. Moreover, the disclosed embodiments can be used with a wide variety of commercially available devices in a wide variety of medical procedures.

[0081] Particular implementations of the subject matter described herein may be implemented to realize one or more of the following potential advantages. The atherectomy devices described herein are specifically configured to more efficiently resect calcified lesions within blood vessels. In some embodiments, the device comprises an abrasive element, the abrasive element configured to move at least a portion thereof away from the central axis of the drive shaft. In some embodiments, the device includes a distal sharpening element configured to expand when it is rotated at a high speed. In this manner, the abrasive elements disclosed herein can be extended further out from the drive shaft to press against the lesion. In other words, the polishing elements disclosed herein have larger polishing and/or scraping areas than other polishing elements.

[0082] In some embodiments, the abrasive element can allow an effectively larger abrasive element to fit within a standard lumen when delivered to a target location. . For example, an abrasive element may be configured to be radially constrained when placed within a lumen and then radially expand as it exits the lumen. The abrasive element may also be configured to radially expand further when rotated. In this manner, the abrasive elements disclosed herein can open a stenosed lesion to a diameter substantially greater than the maximum diameter of the abrasive element and/or the sheath through which the abrasive element is carried. . Thus, the abrasive elements disclosed herein can have improved abrasive coverage, increased scrape area, can reduce treatment time, and/or can reduce restenosis more effectively. can be prevented.

[0083] Various aspects are now described with reference to specific forms or embodiments selected for purposes of illustration. It will be understood that the spirit and scope of the atherectomy systems disclosed herein are not limited to any selected form. Further, it should be noted that the figures provided herein are not drawn to any particular proportion or scale, and that many changes may be made to the illustrated embodiments. A brief introduction to some of the features common to the described embodiments of atherectomy systems is now described.

[0084] To help describe these components of the atherectomy system, the following coordinate terminology is used. A "longitudinal axis" is generally parallel to the elongated sides of the polishing elements disclosed herein. For example, see FIG. A "radial axis" is perpendicular to and extends in a radial direction relative to the longitudinal axis.

[0085] Additionally, as used herein, "longitudinal" refers to a direction substantially parallel to the longitudinal axis, and "radial" refers to a direction substantially parallel to the radial axis. direction parallel to The term "axial" may be used herein and is synonymous with the term "longitudinal" used herein.

[0086] Also, the terms "proximal" and "distal" used to describe the atherectomy system of the present invention are used consistent with the description of the exemplary application (specific illustration). be done. Thus, proximal and distal are used with reference to the handle of the atherectomy system.

[0087] The terms "top", "bottom", "top", "bottom", "bottom", "top", etc. used to describe the atherectomy system of the present invention are illustrated Used with reference to the orientation of the embodiment. For example, the term "top surface" may be used to describe the portion of the polishing element that lies above longitudinal and/or radial axes through the center of the polishing element. The term "lower surface" may be used to describe the portion of the polishing element that lies below the longitudinal and/or radial axis through the center of the polishing element.

[0088] Figure 1 illustrates a rotational atherectomy system 1 according to one embodiment. System 1 comprises a drive system 3 configured to rotate a flexible drive shaft 5 at high speeds (eg 20,000-160,000 rpm). The drive system 3 can comprise an electric motor. Drive system 3 is a Boston Scientific Rotablator, Cardiovascular
Systems Inc. ("CSI") Stealth, CSI Diamondback360, and/or other similar devices may comprise or be designed to have substantially similar portions. The drive shaft 5 may be advanceable over a guidewire (not shown) or through a sheath. The drive shaft 5 can have a proximal end coupled to the drive system 3 and a distal end for insertion into the patient. The drive shaft 5 can extend through the lumen of an artery, for example. In some embodiments, rotational atherectomy system 1 comprises a sheath. In some embodiments, a catheter having a lumen extending therethrough is coupled to the proximal end of the drive shaft. In such embodiments, the drive shaft 5 can extend through the lumen of the catheter.

[0089] As shown in FIG. In some embodiments, this sharpening element 200 is coupled at a location proximal to the distal end of drive shaft 5 . For example, abrasive element 200 may be coupled to drive shaft 5 at a location approximately 20 mm proximal to the distal end of drive shaft 5 . In some embodiments, abrasive element 200 is located approximately 10 mm proximal to the distal end of drive shaft 5 . The drive shaft 5 can be provided with a winding wire. In another embodiment, the drive shaft 5 comprises a tube.

[0090] The polishing element 200 can comprise a proximal end 213 and a distal end 211. As shown in FIG. The abrasive elements may be between about 1 and 25 mm long. In other embodiments, the abrasive elements are about 1 to 15 mm long. In some embodiments, the abrasive elements are about 6 mm long. The abrasive elements disclosed herein can be made of any suitable material or combination thereof. For example, an abrasive element or portion thereof can be made of surgical stainless steel, titanium, tungsten, nitinol, or the like. In some embodiments, the polishing elements are solid as opposed to hollow. In some embodiments, the abrasive element comprises a raised waist located between the proximal and distal ends. In some embodiments, the polishing element has an eccentric shape.

[0091] Turning to FIG. 2, an enlarged view of the polishing element 200 according to the embodiment of FIGS. 1 and 1A is shown. As shown, polishing element 200 comprises a generally cylindrical bead 201 having a beveled end 205 and a lumen 203 extending therethrough. The polishing element 200 may be mounted on a flexible drive shaft 5 that is rotated at high speed by an electric motor. Generally, polishing element 200 is coupled to drive shaft 5 such that polishing element 200 and drive shaft 5 rotate together about a longitudinal axis passing through the center of drive shaft 5 . That is, the polishing elements 200 may be coupled to the drive shaft 5 such that the polishing elements 200 are restrained from moving relative to the drive shaft 5 . In other embodiments, the sharpening elements 200 are configured to be constrained from longitudinal movement relative to the drive shaft 5, but not constrained from transverse and/or lateral longitudinal movement. In some embodiments, polishing element 200 moves in cooperation with at least a portion of drive shaft 5 located within polishing element 200 .

[0092] In some embodiments, at least a portion of the drive shaft 5 positioned within the polishing element 200 is welded to at least a portion of the interior surface of the lumen 203. As shown in FIG. In certain embodiments, abrasive element 200 is welded to the entire interior surface of lumen 203 . In other embodiments, sharpening element 200 is crimped such that at least a portion of lumen 203 engages at least a portion of drive shaft 5 positioned within lumen 203 . In some embodiments, the proximal portion of the lumen is welded to the proximal portion of the drive shaft and the distal portion of the lumen is welded to the distal portion of the drive shaft. For example, in some embodiments, a laser is used to fuse at least a portion of polishing element 200 to at least a portion of drive shaft 5 .

[0093] The polishing element 200 can include a roughened outer surface 207. As shown in FIG. Roughened outer surface 207 can improve the polishing ability of polishing element 200 . In some embodiments, roughened outer surface 207 comprises diamond particles deposited on one or more of the outer surfaces of polishing element 200 . These particles may have a diameter of about 20 μm. Although polishing element 200 is shown as having a roughened overall outer surface, in some embodiments the outer surface is roughened to a lesser extent than the overall outer surface. The roughened exterior surface 207 can be similar to sandpaper and can improve the ability of the abrasive element 200 to excise lesions.

[0094] Example shapes of the polishing element 200 are further illustrated in FIGS. As best shown in FIG. 5, lumen 203 extending through polishing element 200 extends obliquely within generally cylindrical bead 201 . In other words, lumen 203 extends from the bottom left corner of distal end 211 of cylindrical bead 201 to the top right corner of proximal end 213 of cylindrical bead 201, as shown in FIG. In this manner, when polishing element 200 is attached to flexible drive shaft 5 positioned within lumen 203, for example as shown in FIG. It extends radially farther from the flexible drive shaft 5 than the other outer surfaces of the element 200 . In this way, the distal 211 and proximal 213 ends can have local centers of mass that are diagonally opposite each other and from the center of the longitudinal axis of the drive shaft 5 . exist at a distance. For example, as shown in FIG. 1A, the local center of mass of distal end 211 of polishing element 200 is located above the top surface of drive shaft 5 and the local center of mass of proximal end 213 of polishing element 200 is above the top surface of drive shaft 5 . are located on the lower surface of the drive shaft 5 .

[0095] In some embodiments, the beveled end 205 is shaped to improve the trackability of the abrasive element 200 through the vasculature. For example, one or more angled surfaces can improve the ability to insert polishing element 200 through tortuous paths and/or narrow passages. The beveled end 205 can also help facilitate the passage of the abrasive element 200 through calcified material within the blood vessel.

[0096] Although a generally cylindrical bead 201 is shown, other shapes are also contemplated. For example, in some embodiments, the polishing element 200 can have a waist that is larger or smaller in diameter than the rest of the generally cylindrical bead 201 .

[0097] As shown in FIG. 5, the angle of lumen 203 can create two offset local centers of mass located near the distal and proximal ends of polishing element 200. . That is, the oblique lumen 203 causes more mass to reside below the longitudinal axis extending through the center of the polishing element 200 at the proximal end 213 than at the distal end 211 . Similarly, oblique lumen 203 causes more mass to reside above the longitudinal axis extending through the center of polishing element 200 at distal end 211 than at proximal end 213 .

[0098] In other embodiments, the distal and/or proximal ends may be made of a material that is heavier than the material of the rest of the polishing element 200. FIG. For example, in some embodiments, beveled end 205 and/or at least a portion of the volume disposed under beveled end 205 is made of a material that is heavier than the material of the remainder of polishing element 200 . For example, in some embodiments, at least a portion of distal end 211 and proximal end 213 of generally cylindrical bead 201 are made of tungsten, while the remainder of generally cylindrical bead 201 is made of tungsten. parts are made of steel. In this way, the heavier material of distal end 211 and proximal end 213 can also distribute two masses, which are eccentrically located on both ends and sides of polishing element 200. do. In some embodiments, at least a portion of polishing element 200 is hollow. For example, in some embodiments, at least a portion of the distal end and at least a portion of the proximal end comprise at least one hollow portion.

[0099] In operation, the distribution of mass within the sharpening element 200 can change the sharpening angle of the sharpening element 200 with respect to the longitudinal axis extending through the lumen of the blood vessel. For example, at low speeds, the sides of the generally cylindrical bead 201 can contact and excise material deposited on the wall of the vessel lumen. At high speeds, the offset local center of mass can cause the abrasive element 200 to wobble with respect to the longitudinal axis extending through the vessel. In this manner, the beveled end 205 of the abrasive element 200 can also contact and excise material deposited on the wall of the vessel lumen. In some embodiments, this variable sharpening angle of sharpening element 200 can improve the effectiveness of the atherectomy device.

[0100] In some embodiments, the mass distribution within the abrasive element 200 can increase the stiction that the abrasive element 200 has with materials deposited on the walls of the vessel lumen. For example, mass distribution within the polishing element 200 can reduce the degree to which the polishing element bounces away from the material it contacts when rotated. Accordingly, in some embodiments, distributing the mass of the abrasive element 200 can improve the effectiveness of the atherectomy device. The relative size and shape of polishing elements 200 may also be varied to increase stiction. For example, in some embodiments, the abrasive element 200 includes one or more protrusions and/or asperities to increase the stiction of the abrasive element with the material being ablated.

[0101] As best shown in FIGS. and a distal cutout 221 in communication with the . Lumen 203 thus opens upward and distally, and downwardly and proximally. Proximal notch 223 and distal notch 221 can provide weld areas. That is, the welds can be disposed at least partially within proximal cutout 223 and/or distal cutout 221 to secure polishing element 200 to drive shaft 5 . In some embodiments, proximal cutout 223 and distal cutout 221 maximize the distance between two displaced local centers of mass while maintaining a low profile while carrying polishing element 200. can help you do In some embodiments, the cutouts can remove mass from portions of the proximal and distal ends to create two offset local centers of mass.

[0102] In certain embodiments, the polishing elements 200 can move axially at an angle to the longitudinal axis of the drive shaft 5. As shown in FIG. In other words, at least part of the drive shaft 5 can pass through at least part of the distal cutout 221 and/or the proximal cutout 223 . Accordingly, the polishing elements 200 are coupled to the drive shaft 5 such that longitudinal movement relative to the drive shaft 5 is inhibited, but longitudinal movement transverse and/or lateral to the drive shaft 5 is restricted. is not restricted from doing. Accordingly, when drive shaft 5 and sharpening element 200 are rotated about the longitudinal axis, the proximal and/or distal ends of sharpening element 200 can be further away from the central axis of drive shaft 5 . . In other embodiments, sharpening element 200 is mounted on drive shaft 5 such that it is restrained from moving relative to drive shaft 5 . In certain embodiments, the sharpening element 200 can be coupled to the drive shaft 5 such that the distal end of the sharpening element 200 can move radially relative to the drive shaft.

[0103] FIGS. 8A-8D illustrate exemplary positions of the polishing elements 200 attached to the flexible drive shaft 5. FIG. As shown in FIGS. 8A-8D, welds 800 can secure polishing elements 200 to drive shaft 5 . Welds may be placed at or near the proximal and distal ends of the abrasive element 200 . As shown in FIGS. 8B and 8D, welds 800 may be arranged around the circumference of lumen 203 and drive shaft 5 .

[0104] In FIGS. 8A-8B, polishing element 200 attached to flexible drive shaft 5 is shown in a restrained position within sheath 801. As shown in FIG. Abrasive elements 200 can move to an unconstrained position when advanced out of the sheath, as shown in FIGS. 8C-8D. That is, the effective diameter of polishing element 200 increases when polishing element 200 exits sheath 801 (eg, length _d2 in FIG. 8D is greater than _d1 in FIG. 8B). In some embodiments, the polishing element 200 has an unrestrained or deployed profile that is 10-60% greater, or 35-45% greater, or at least 40% greater than the restrained profile. A portion of the sharpening element 200 that overlaps a portion of the drive shaft 5 may be secured together such that the sharpening element 200 and the portion of the drive shaft 5 within the sharpening element 200 move together.

[0105] Figures 8E-8J illustrate exemplary positions of a polishing element 200 attached to a flexible drive shaft 5 according to another embodiment. 8E-8J show polishing element 200 attached to flexible drive shaft 5 by weld 800. FIG. Although the attachment means are described as welds, other attachment means may be used. For example, in some embodiments an adhesive is used to attach the polishing element 200 to the flexible drive shaft 5 . As shown, weld 800 is located approximately in the center of abrasive element 200 and couples the outer surface of drive shaft 5 to the inner surface of lumen 203 . However, the weld 800 can cover more or less than the area shown. For example, in some embodiments, weld 800 couples the entire length of lumen 203 to drive shaft 5 . In other embodiments, weld 800 does not contact all diametric surfaces of lumen 203 . As discussed above, weld 800 prevents polishing element 200 from moving longitudinally relative to drive shaft 5 . Depending on the type, size and/or location of the weld 800, the abrasive elements 200 may or may not move radially relative to the drive shaft 5 during rotation.

[0106] In certain embodiments, the weld 800 allows the polishing element 200 to pivot about the weld 800. As shown in FIG. That is, a portion of polishing element 200 can move radially and/or rotate. In other embodiments, welds 800 are positioned at the proximal and distal ends of the abrasive element as described above. In some embodiments, the portion of the sharpening element 200 that overlaps the portion of the drive shaft 5 is secured together such that the sharpening element 200 and the portion of the drive shaft 5 within the sharpening element 200 cooperate. Moving.

[0107] In FIGS. 8E-8F, the polishing element 200 attached to the flexible drive shaft 5 is shown in a restrained position within the sheath 801. FIG. The polishing elements 200 can move to the unconstrained position when advanced out of the sheath as shown in FIGS. 8G-8H. That is, the effective diameter of polishing element 200 increases when polishing element 200 exits sheath 801 (eg, _d3 in FIG. 8J is greater in length than _d2 in FIG. 8H). In some embodiments, the polishing element 200 has an unrestrained or deployed profile that is 10-60% greater than the restrained profile, or 35-45% greater, or at least 40% greater. In certain embodiments, when polishing element 200 and flexible drive shaft 5 are rotated as shown in FIGS. 8I-8J, centrifugal force causes beveled end 205 of polishing element 200 to move toward the flexible drive shaft. Further away from the central axis of 5. Accordingly, the polishing range of the polishing elements 200 can be further increased and the polishing elements 200 can have an even larger effective diameter when rotated (e.g., _d3 of FIG. 8J corresponds to FIG. 8H). of length greater than ₂ ). Thus, within a tightly closed vessel, the centrifugal forces acting on the local centers of mass of the distal and proximal ends of the abrasive element 200 allow the abrasive element 200 to have a larger effective diameter, thus Device effectiveness is increased and/or treatment time is reduced.

[0108] Figure 9 schematically illustrates an exemplary operation of the polishing elements disclosed herein. When the vessel 900 is opened by the rotating abrasive element 200, 300, 1000, a second action may also be caused and/or facilitated by the shape of the abrasive element(s). The minor trajectory 920 represents the path that the outermost radially facing surface of the polishing element may follow as the drive shaft 5 and polishing element are rotated. Small trajectory 920 can represent the path of polishing element 200 as it wobbles about a longitudinal axis through its center. In other words, the effective diameter of small track 920 can be increased by relative movement of the polishing element with respect to a longitudinal axis through the center of the polishing element and/or by physical deformation of the polishing element. In some embodiments, the small track 920 can increase in effective diameter as the polishing element is rotated. In certain embodiments, for example, an effective diameter of a polishing element can have a first diameter at a first rotational speed and a second effective diameter at a second rotational speed. The second effective diameter can be larger in size than the first effective diameter when the second rotational speed is greater than the first rotational speed. In some embodiments, for example, if polishing elements 200 are mounted on drive shaft 5 to allow relative radial movement, this relative radial movement further increases the size of the small tracks. can be made Thus, the movement of the drive shaft 5 and the polishing elements can extend the scraping area and/or polishing extent of the polishing elements beyond the small trajectory 920 .

[0109] In certain embodiments, for example, where the polishing elements have ends with local centers of mass distributed opposite from each other and away from the central axis of the drive shaft 5, the polishing elements , the drive shaft 5 and abrasive elements can create a large trajectory 910 by centrifugal force (particularly after sufficient space has been created within the lesion at high rotational speeds, e.g., 30,000 rpm or more). can. Accordingly, the polishing elements disclosed herein can be configured such that the scraping region and/or polishing extent of the polishing elements extends beyond the small trajectory 920 .

[0110] Figures 10A-10B show a polishing element 300 according to a similar embodiment as described above. As shown, polishing element 300 has two local centers of mass. The two local centers of mass are spaced apart (having approximate locations at 301 and 303) and located at off-center diagonal corners of the flexible drive shaft 5. FIG. Abrasive element 300 can comprise a substantially straight lumen extending from proximal end 313 to distal end 311 of abrading element 30 . Polishing element 300 may be substantially cylindrical in shape. Abrasive element 300 may be mounted on drive shaft 5 as shown in FIG. 10A such that distal center of mass 301 is above the longitudinal center of drive shaft 5 and proximal center of mass 303 is at the drive shaft. It is located below the longitudinal center of the shaft 5 . Thus, as the polishing elements 300 are rotated, the polishing range of the polishing elements is increased beyond the small trajectory as described above. Further, as shown in FIG. 10B, polishing elements 300 have a larger effective diameter than sheath 801 from which polishing elements 300 are deployed. Abrasive element 300 may include curved edges to improve slidability of the device through tortuous paths and/or through lumens.

[0111] Figures 11-30 illustrate a polishing element 400 according to another embodiment. For example, as shown in FIG. 11, polishing element 400 comprises slotted tube 409 having at least two projections extending from polishing element 400 . As shown, the protrusion comprises a two-part bead 405 attached to the polishing element 400 . Abrasive element 400 can have a distal end 411 and a proximal end 413 . At least a portion of bead 405 includes a roughened exterior surface 407 . Similar to the embodiments described above, sharpening element 400 may be coupled to the proximal portion of flexible drive shaft 5 . As will be explained in further detail, the slotted tube 409 may be configured to compress so that the abrasive elements 400 pass through the sheath for low profile transfer and expand during high speed rotation. can be used to increase the polishing range.

[0112] FIG. 12 shows an exploded view of the polishing element 400. As shown in FIG. As shown, the two-part bead 405 comprises two molded halves with roughened outermost surfaces 407 . As shown, the two-part bead 405 is shaped such that the surface of the bead 405 facing the slotted tube 409 contacts the curved outer surface of the slotted tube 409 . The two-part bead 405 has a shape such that the bead does not extend over and/or cover any portion of the slot 416 . Bead 405 may be coupled to slotted tube 409 by any suitable means. For example, bead 405 may be welded, glued, and/or fused to slotted tube 409 . Bead 405 may be made of the same or different material as tube 409 . In some embodiments, slotted tube 409 and bead 405 are made as one piece.

[0113] As shown in FIGS. 13-16, the slotted tube 409 can comprise a substantially cylindrical tube having a lumen 433 extending longitudinally therethrough. Slot 416 may be generally rectangular in shape and may extend radially through tube 409 and communicate with lumen 433 . Tube 409 may be made from one or more materials that are sufficiently flexible to contract and/or expand under applied force. In some embodiments, tube 409 may be configured to contract in size when an external force is applied and to substantially return to its original form and shape when the external force is removed. In some embodiments, tube 409 can be configured to stretch when an external force is applied and to substantially return to its original form and shape when the external force is removed.

[0114] FIGS. 17-21 further illustrate a bead 405. FIG. As shown, bead 405 includes a curved lower surface 440 shaped to contact the non-slotted portion of slotted tube 409 . The bead 405 comprises two sloped transition portions 445 and a central generally cylindrical portion having a roughened surface 407 . In some embodiments, bead 405 has a shape that is thicker in regions of slotted tube 409 further away from slot 416 . In some embodiments, bead 405 is formed from a relatively hard and/or dense material compared to tube 409 .

[0115] As shown in FIG. separated. The polishing element 400 thus comprises two local centers of mass both offset from the longitudinal center of the flexible drive shaft 5 . Although the local centers of mass of the polishing elements 400 are radially spaced apart, unlike the embodiment shown in FIGS. 1-10B, the local centers of mass are not longitudinally spaced from each other. However, in some embodiments, polishing elements 400 can be configured such that this local center of mass is both radially and longitudinally offset. For example, the two beading elements 409 may not be symmetrically attached to the slotted tube 409 . In other words, the first beading element may be coupled to slotted tube 409 such that its proximal-most end is positioned over the proximal-most end of slot 416, while , the second beading element may be coupled such that its distal-most end is positioned over the distal-most end of slot 416 .

[0116] As also shown in FIG. 22, the drive shaft 5 need not pass through the entire length of the polishing element 400; Accordingly, the proximal end of the sharpening element 400 may be fixed to the distal end of the first drive shaft 5 and the distal end of the sharpening element 400 may be proximal to a portion of the second drive shaft 5 . It may be fixed to the proximal end. With the drive shaft removed from the center of the polishing element 400, the polishing element can be compressed and the two beading elements 409 can move toward each other, thereby giving the polishing element a low profile. can take In other embodiments, the drive shaft 5 passes through the entire length of the polishing element.

[0117] FIGS. 22-24 show that the sharpening element 400 can generally comprise a central sharpening region 450 and proximal and distal attachment regions 455. As shown in FIG. Central abrasive region 450 may be coupled to proximal and distal attachment regions 455 by interstitial regions 460 . Proximal and distal attachment regions 455 are portions of slotted tube 409 that are secured to flexible drive shaft 5 that extends through lumen 433 of slotted tube 409 . The proximal and distal attachment regions 455 may comprise welds and/or crimps or any other suitable securing means. The proximal and distal attachment regions 455 are thus restrained from moving away from the flexible drive shaft 5 . In embodiments in which the drive shaft 5 passes through the entire length of the sharpening element, the drive shaft may be fixed to the attachment region 455 but not to the tube gap region 460 and central sharpening region 450 . Thus, the tube clearance area 460 and the central abrasive area 450 are unconstrained and can move toward and/or away from the flexible drive shaft 5 .

[0118] FIGS. Polishing element 400 is shown in a rest configuration in FIGS. The radial thickness of the device in this unrestrained rest state is labeled as dl. Polishing element 400 is shown in restrained configuration in FIGS. 26 and 28, polishing element 400 is positioned within sheath 801. In FIGS. In this constrained configuration, the radial thickness of the device is that of sheath 801, labeled as d2. As shown, the radial thickness d2 in the constrained configuration is less than the radial thickness d1 in the unconstrained configuration. As shown in FIGS. 26 and 28, in the restrained position the slotted tube is compressed such that the slots have a width less than that in the unrestrained configuration of FIGS. In other words, slotted tube 409 allows polishing element 400 to be radially compressed. In this manner, polishing element 400 can have a larger effective diameter than sheath 801 in which it is carried.

[0119] In some embodiments, the polishing element 400 naturally returns to its unrestrained configuration within a relatively short time after being removed from the sheath 801. FIG. In other words, the material of polishing element 400 is selected such that slotted tube 409 springs back to its unrestrained configuration as soon as the passive restraint applied by the sheath is removed. In other embodiments, polishing elements 400 return to their unrestrained configuration after being rotated at relatively low speeds (eg, 5000 rpm or less).

[0120] In Figures 27 and 30, the polishing element 400 is shown in an expanded configuration. For example, when polishing element 400 is rotated at high speed, centrifugal force causes polishing element 400 to expand as slotted tube 409 expands. That is, because the two-part bead 405 has a local center of mass distributed away from the central axis of the slotted tube 409 and the drive shaft 5, rotation also pulls the bead 405 away from the tube axis by centrifugal force. So slotted tube 409 expands. Thus, when polishing element 400 is rotated at high speeds (eg, above about 90,000 rpm), polishing element 400 can expand to diameter d3, which is greater than d1 and d2. Thus, the abrasive extent of abrasive element 400 extends beyond its unrestrained diameter d2. Although d3 is shown to be significantly larger than d2, it is understood that the diameter of polishing element 400 may not actually increase to such an extent when the device is rotated. The relative sizes of d1-d3 are merely to aid in easy understanding of the functionality of the device and do not indicate the actual percentage of expansion in use.

[0121] In some embodiments, the polishing element 400 naturally returns to its unrestrained configuration in a relatively short time after it stops rotating. In other words, the material of sharpening element 400 is selected such that slotted tube 409 returns to its unconstrained configuration as soon as drive shaft 5 comes to rest. In other embodiments, polishing elements 400 return to a substantially unrestrained configuration as soon as drive shaft 5 comes to rest and transition to a restricted configuration when retracted into sheath 801 .

[0122] Although the polishing element 400 has been shown and described as a two-piece bead 405 coupled to a slotted tube 409, a unitary construction is also contemplated. Thus, in some embodiments, the slotted tube 409 can have thicker walls in the central region of the slotted tube 409 than the walls at its proximal and distal ends. At least a portion of the slotted tube can have a polished outer surface. In other words, the thickness of the walls on both sides of the slot 416 can increase from the two ends of the slotted tube 409 and reach a peak thickness at the center of the slotted tube 409 . Wall thickness variations can create two local centers of mass distributed away from the central axis of slotted tube 409 and drive shaft 5 . The variation in wall thickness can form one or more projections extending radially outward from the center of the polishing element. Thus, when the device is rotated at high speed, centrifugal force causes the two local centers of mass to pull the slots open, radially expanding the polishing elements 400 . Similarly, materials of different masses can be used to create a slotted tube that expands when the slotted tube is rotated at high speed.

[0123] Figures 31-36 illustrate a polishing element 500 according to another embodiment. Polishing element 500 is configured such that two-part bead 505 extends at least partially over slot 416 of slotted tube 409 when polishing element 500 is unconstrained and at rest, except that: Similar to polishing element 400 .

[0124] For example, as shown in FIGS. 31-34, the two-part bead 505 extends substantially over the slot of the slot 416 of the slotted tube 409, thereby allowing the two-part bead to extend only at the small air gap 515. 505 is separated. For example, as shown in FIGS. 35A-35B, the two-part bead 505 is pressed together when restrained by the sheath 801 similar to the embodiment shown in FIG. 27 and 30, described above, when the polishing elements 500 are rotated at high speeds as shown in FIGS. forced to leave. Accordingly, diameter d3 of polishing element 500 in operation is greater than diameter d1 when the device is in its unconstrained configuration.

[0125] Figures 37-47 illustrate a polishing element 600 according to another embodiment. For example, as shown in FIGS. 37-40, the abrasive element 600 includes a slotted tube 509 with support bars 520 extending on opposite sides of the slotted tube 509 for the longitudinal length of the slot, thereby providing two openings. Similar to polishing element 400 described above, except to create 516 and 517 . Support rods 520 may help stiffen polishing elements 600 . As shown in FIG. 42, slotted tube 509 comprises a substantially cylindrical tube having a lumen 433 extending longitudinally therethrough.

[0126] Figures 43-48 illustrate various configurations of the polishing element 600 in use. Similar to FIGS. 26 and 35A, abrasive elements 600 can be constrained to a smaller maximum diameter when an external force is applied to, for example, two-part bead 405 . As shown in FIG. 44, the slotted tube 509 may be compressed within the sheath 801, thereby reducing the radial width of the slotted tube 509. FIG. As explained above, polishing element 600 can return to an unconstrained configuration when removed from sheath 801 as shown in FIG. Similar to the embodiments shown in FIGS. 27, 30 and 36A and described above, the abrasive element 600 can expand in diameter when rotated at high speeds and expand when rotation is stopped. It can return to its unrestrained form.

[0127] Figures 49-52 show a polishing element 700 according to another embodiment, similar to the polishing element 400 (eg, as shown in Figure 11) except that the two-part bead 705 has a different shape. Although the two-part bead 705 is shown as not extending over the slot 416 of the slotted tube 409, in some embodiments the two-part bead 705 extends at least partially or completely over the slot.

[0128] Figures 53-56 show a polishing element 1000 according to another embodiment, similar to polishing element 700, except that beads 705 are longitudinally offset from each other. Thus, as explained above, the polishing range of polishing element 1000 extends beyond a small trajectory when polishing element 1000 is rotated by drive shaft 5 .

[0129] The atherectomy system disclosed herein can be used, for example, in the following manner. A guidewire is inserted into the patient and can be advanced over the area of interest. A rotatable drive shaft with an abrasive element attached to its proximal portion can be advanced over the guidewire. A rotatable drive shaft and an abrasive element can be advanced through the sheath. In some embodiments, the abrasive elements expand radially as they are advanced out of the sheath. In some embodiments, the abrasive element expands to a first diameter when rotated at a first speed and expands to a diameter greater than the first diameter when rotated at a second speed greater than the first speed. Expand to a larger second diameter. Abrasive elements may be advanced over the arterial lesion. Abrasive elements can be rotated to ablate arterial lesions. Fluid may or may not be carried through the sheath. The arterial lesion may be resected and the abrasive element, drive shaft, sheath and guidewire removed from the patient. In some embodiments, suction is applied to draw material through the drive shaft.

[0130] Those skilled in the art will appreciate that the disclosed aspects and features shown herein are not limited to any particular embodiment of an atherectomy system, and that one of the features described herein It will be appreciated that an atherectomy system comprising or more than one can be designed for use in a variety of medical procedures. Moreover, those skilled in the art will recognize the interchangeability of various features from different embodiments. For example, features of polishing elements disclosed in various embodiments may be interchanged between embodiments. In addition to the variations described herein, other known equivalents of each feature can be mixed and matched by those skilled in the art to provide abrasive elements and atherectomy in accordance with the principles of the present invention. Techniques can be built.

[0131] It should, of course, be understood that not necessarily all objectives or advantages may be achieved by any particular embodiment of the invention. Thus, for example, the invention may achieve or optimize one advantage or group of advantages as taught herein, and achieve other objectives or advantages necessarily as may be taught or suggested herein. Those skilled in the art will recognize that it may be embodied or performed in such a manner as not necessarily.

[0132] Furthermore, while the invention has been disclosed in the context of particular embodiments and examples, the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or the invention. and the obvious modifications and equivalents thereof. Accordingly, it is intended that the scope of the inventions disclosed herein should not be limited by the specific disclosed embodiments described above.

REFERENCE SIGNS LIST 1 rotary atherectomy system 3 drive system 5 drive shaft 30, 200, 300, 400, 500, 600, 700, 1000 abrasive element 201, 405, 505, 705 bead 203, 433 tube Lumens 205 Beveled end 207, 407 External surface 211, 311, 411 Distal end 213, 313, 413 Proximal end 221 Distal notch 223 Proximal notch 301 Distal center of mass 303... Proximal center of mass 409, 509... Slotted tube 416... Slot 440... Lower surface 445... Transition section 450... Central abrasive area 455... Attachment area 460... Tube clearance area 515... Void 516... Opening 520... Support bar DESCRIPTION OF SYMBOLS 800... Welding part 801... Sheath 900... Blood vessel 910, 920... Track

Claims (7)

A rotational atherectomy system comprising:
a drive system;
a drive shaft having a proximal end coupled to the drive system and a distal portion;
an abrasive element having a substantially cylindrical shape having a lumen configured to receive the distal portion of the drive shaft and attached to the drive shaft at the lumen ;
The polishing element has an axially distal end with a first radially offset center of mass, the first center of mass being radially offset from the drive shaft. cage,
The polishing element has an axially proximal end having a second radially offset center of mass proximal to and opposite the first center of mass. have
said second center of mass is located proximal to said first center of mass and offset in a second radial direction from said drive axis ;
The rotary atherectomy system wherein said second radial direction is primarily opposite said first radial direction. The rotary atherectomy system of claim 1, comprising:
The rotary atherectomy system, wherein the abrasive element comprises a waist positioned between the distal end and the proximal end. 3. The rotational atherectomy system of claim 1 or 2, wherein
The rotary atherectomy system, wherein the abrasive element has an eccentric shape. A rotary atherectomy system according to any one of claims 1 to 3, wherein
A rotary atherectomy system, wherein the drive shaft is advanced over a guidewire and configured to rotate about the guidewire. A rotary atherectomy system according to any one of claims 1 to 4, wherein
The rotary atherectomy system, wherein the abrasive element includes an outer surface that is rough compared to the outer surface of the drive shaft. A rotary atherectomy system according to any one of claims 1 to 5 , wherein
The rotary atherectomy system, wherein the abrasive element comprises tungsten. 7. A rotary atherectomy system according to any one of claims 1-6 ,
The rotary atherectomy system, wherein the distal end and the proximal end of the sharpening element are formed of a material that is heavier than the rest of the sharpening element.

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