JP7651827B2 - Catheter Tips - Google Patents

Description

The present disclosure relates to a catheter tip that is fixed to the distal end of a catheter and a catheter to which the tip is fixed.

In treatments such as percutaneous coronary intervention (PCI) to widen narrowed blood vessels, a balloon catheter that expands the narrowed treatment area is placed at the narrowed area using a guiding catheter. The guiding catheter is a catheter into which a balloon catheter can be inserted, and is inserted up to just before the coronary artery. The balloon catheter containing the stent is guided to the narrowed area through the guiding catheter.

In a treatment for widening a narrowed portion of a blood vessel, such as PCI, a filter for capturing emboli may be placed distal to the treatment site where a balloon catheter for expanding the narrowed treatment site is placed, in order to capture thrombi and the like scattered by the treatment. The emboli capture catheter has a long shaft, a filter section (filter for capturing emboli) formed on the shaft, and a distal tip formed distal to the position where the filter section of the shaft is formed. The emboli capture catheter is combined with a long cylindrical delivery catheter, and is inserted into a guiding catheter with the filter section housed in the delivery catheter, and is pushed forward to the distal side of the treatment site. After the emboli capture catheter is placed distal to the treatment site, the delivery catheter is removed to deploy the filter section (see, for example, Patent Document 1).

JP 2016-30035 A

However, it is extremely difficult to guide the embolus capture catheter distal to the treatment site by manipulating the distal guidewire, and depending on the vascular course, it may not be possible to guide the embolus capture catheter distal to the treatment site. In addition, when retrieving a filter device after use, a retrieval catheter that houses the filter must be inserted, but it has become clear that a problem occurs in that the retrieval catheter gets caught on the stent expanded by the balloon of the balloon catheter, deforming the stent.

On the other hand, when guiding a device into a small blood vessel, a support catheter that is thinner than the guiding catheter may be used. The support catheter has a tube portion that is thinner than the guiding catheter and a shaft that extends from the base end of the tube portion, and the tip of the tube portion can be inserted beyond the tip of the guiding catheter into the coronary artery.

The inventors of the present application considered using a support catheter in conjunction with the guiding catheter for emboli capture. However, it became clear that when inserting the emboli capture catheter into the tube portion of the support catheter, the coiled tip portion is often not inserted correctly into the support catheter, and becomes caught in the gap between the guiding catheter and the support catheter.

This problem is not limited to embolus capture catheters, but can occur with any catheter that is guided into a blood vessel using a guiding catheter and a support catheter.

The objective of the present disclosure is to make it possible to easily insert a catheter into a support catheter when guiding the catheter into a blood vessel using a guiding catheter and a support catheter.

One aspect of the distal tip of the present disclosure is fixed to the distal end of a shaft section that is guided to an affected area using a guiding catheter and a support catheter that is inserted into the guiding catheter, and includes an intermediate section and a forward section that is located distal to the intermediate section, has a larger diameter than the intermediate section, a smaller diameter than the inner diameter of the support catheter, and a larger diameter than the difference between the inner diameter of the guiding catheter into which the support catheter is inserted and the outer diameter of the support catheter, and the distal end of the shaft section protrudes distally from the forward section.

One aspect of the tip tip is that by fixing it to the tip of the shaft of an embolus capture catheter or the like, it is possible to prevent the tip of the shaft from getting caught in the gap between the delivery catheter and the support catheter. This makes it possible to guide the catheter smoothly.

In one embodiment of the tip, the tip of the shaft portion may protrude from the tip of the front portion by 0.1 mm or more and 2 mm or less. This configuration makes it difficult for the front portion of the shaft portion to get caught in a gap, while making it easier to overcome a narrowed portion, thereby improving the operability of the shaft portion.

In one embodiment of the tip, the length of the front part can be longer than the outer diameter of the front part. This configuration makes it less likely to get caught in a gap.

In one embodiment of the tip, the middle section may have a maximum outer diameter at the front section. This configuration prevents a large constriction from occurring between the middle section and the front section, improving the strength of the tip and preventing breakage between the middle section and the front section.

One embodiment of the tip tip further comprises a rear section provided on the base end side of the intermediate section, the intermediate section having a diameter larger than the inner diameter of the delivery catheter into which the shaft section is inserted, and the rear section may have a diameter smaller than the inner diameter of the delivery catheter. In this way, a part of the base end side of the tip tip can be accommodated in the delivery catheter, and the tip tip and the delivery catheter are integrated to prevent kinking at the base end side of the tip tip, and the tip tip can be easily followed even in meandering blood vessels, further improving operability.

One aspect of the embolus capture catheter of the present disclosure comprises the distal tip of the present disclosure and a shaft portion to which the distal tip is fixed, and the shaft portion has a filter portion for embolus capture that is spaced apart from the base end of the distal tip. With this configuration, it is possible to realize an embolus capture catheter that is less likely to get caught in the gap between the delivery catheter and the support catheter.

The distal tip of the present disclosure makes it possible to smoothly guide the catheter when guiding the catheter into a blood vessel using a guiding catheter and a support catheter.

FIG. 1 is a perspective view showing an embolus capture catheter according to one embodiment. FIG. 2 is a perspective view showing the state in which the embolus capturing catheter is set in the delivery catheter. FIG. 13 is a perspective view showing an operation of guiding an embolus capturing catheter set in a delivery catheter to an affected area using a guiding catheter and a support catheter. 13 is a photograph showing a second tip for evaluation. 13 is a photograph showing a third tip for evaluation. 13 is a photograph showing a fourth tip for evaluation. FIG. 2 is a perspective view showing a tip according to one embodiment. FIG. 2 is a plan view showing a tip according to one embodiment. FIG. 2 is a diagram showing an end face on the distal end side of a distal tip according to one embodiment. FIG. 2 is a diagram showing an end face on the base end side of a distal tip according to one embodiment. 10 is a cross-sectional view taken along line XI-XI of FIG. 9. FIG. 2 is a plan view showing a state in which a filter portion of an embolus capture catheter according to one embodiment is housed. FIG. 2 is a front view showing a state in which a filter portion of an embolus capture catheter according to one embodiment is housed. FIG. 2 is a rear view showing a state in which the filter portion of the embolus capture catheter according to one embodiment is housed. FIG. 2 is a left side view showing a state in which a filter portion of the embolus capture catheter according to one embodiment is housed. FIG. 2 is a right side view showing the filter portion of the embolus capture catheter according to one embodiment in a housed state. FIG. 2 is a plan view showing a state in which a filter portion of an embolus capture catheter according to one embodiment is deployed. FIG. 2 is a front view showing a state in which a filter portion of an embolus capture catheter according to one embodiment is deployed. FIG. 2 is a rear view showing the filter portion of the embolus capture catheter according to one embodiment in a deployed state. FIG. 2 is a left side view showing the filter portion of the embolus capture catheter according to one embodiment in a deployed state. 1 is a right side view showing a state in which a filter portion of an embolus capture catheter according to one embodiment is deployed.

As shown in Figures 1 and 12 to 21, the distal tip 100 of this embodiment is fixed to the distal end of the shaft portion 151 so that the distal end 151a of the shaft portion 151 protrudes toward the distal end. The distal tip 100 has an intermediate portion 101, a rear portion 102 that is located closer to the base end than the intermediate portion 101 and has a smaller diameter than the intermediate portion 101, and a front portion 103 that is located closer to the distal end than the intermediate portion 101 and has a larger diameter than the intermediate portion 101. The side that is inserted into the patient's body is referred to as the distal side, and the opposite side is referred to as the proximal side.

In this embodiment, the shaft portion 151 to which the tip tip 100 is fixed constitutes the embolus capture catheter 10. The main body of the shaft portion 151 is a normal catheter shaft made of stainless steel, platinum, or the like. The shaft portion 151 is processed into a coil shape about 100 mm from the tip so that it can be easily bent along the blood vessel. On the base end side of the shaft portion 151 from the tip tip 100, a filter portion 152 is formed, which has a cage-shaped portion 161 made of a self-expanding metal wire and a porous filter 162 attached to the tip side of the cage-shaped portion 161. Honeycomb pipes 154A and 154B for fixing the filter portion 152 are attached to the tip side and base end side of the filter portion 152, respectively. The honeycomb pipes 154A and 154B can also be used as contrast rings.

As shown in FIG. 2, the shaft portion 151 constituting the embolus capture catheter 10 is inserted into the first catheter 121, which is a delivery catheter. The first catheter 121 has a tip side portion 171, a base end side portion 172 fixed to the base end portion of the tip side portion 171, an insertion portion (not shown) fixed to the base end portion of the tip side portion 171 and the tip portion of the base end side portion 172 when inserted into the tip side portion 171, and a connector portion 173. The tip side portion 171 and the insertion portion are hollow elongated members made of synthetic resin or the like, and the base end side portion 172 is a hollow elongated member made of metal such as stainless steel or synthetic resin or the like. The base end portion of the insertion portion (the base end portion of the tip side portion 171) forms a port portion 174 that opens to the outside. However, the first catheter 121 is not limited to such a configuration, and may be any type as long as it can deliver the embolus capture catheter 10 to the lesion site. Additionally, a reinforcing braid may be provided at the tip of the first catheter 121.

As shown in Figures 7 to 11, in this embodiment, the outer diameter of the rear part 102 of the tip tip 100 is smaller than the inner diameter of the tip side part 171 of the first catheter 121, and the outer diameter of the middle part 101 is larger than the inner diameter of the tip side part 171 of the first catheter 121. When the base end of the shaft part 151 is inserted from the tip side of the first catheter 121, as shown in Figure 12, the filter part 152, the honeycomb pipes 154A and 154B, and the rear part 102 of the tip tip 100 are housed in the first catheter 121, and the middle part 101 and the front part 103 of the tip tip 100 and the tip 151a of the shaft part 151 are exposed from the tip of the first catheter 121. In this state, the base end part of the shaft part 151 is pulled out of the first catheter 121 from the port part 174 of the first catheter 121.

As shown in FIG. 3, an assembly 20 formed by combining the embolus capture catheter 10 and the first catheter 121 is inserted into the second catheter 122, which is a support catheter, and the third catheter 123, which is a guiding catheter. The assembly 20 protrudes from the tip of the second catheter 122 and is pushed forward until it reaches a predetermined position distal to the treatment site in the blood vessel. By removing the first catheter 121 at the predetermined position, the filter portion 152 is exposed outside the first catheter 121, as shown in FIG. 17, and the filter portion 152 is deployed.

After use, the embolus capture catheter 10 can be retrieved by storing the filter portion 152 in a retrieval catheter that has a configuration similar to that of the delivery catheter. Alternatively, the embolus capture catheter 10 can be retrieved by storing the filter portion 152 using a support catheter instead of a retrieval catheter. Using a support catheter is preferable because it can prevent the catheter tip from getting caught on the stent or deforming the stent, compared to guiding the retrieval catheter beyond the expanded portion caused by the stent. In this case, one part (retrieval catheter) is not required, and the operation of pushing the retrieval catheter from the hand side to a predetermined peripheral position in the blood vessel is also not required, improving work efficiency and reducing operational errors.

The second catheter 122 has a tubular main body 181, a base end shaft 182 extending from the base end of the main body 181, and a protective member 183 provided at the base end of the base end shaft 182. The main body 181 is, for example, a three-layer tube with a mesh member made of stainless steel embedded between an inner layer and an outer layer, and has an inner diameter that allows the first catheter 121 to be inserted. The base end shaft 182 is, for example, a long wire made of stainless steel coated with tetrafluoroethylene. The practitioner can operate the second catheter 122 by grasping and moving the base end shaft 182. A tip tip made of a radiopaque material can be provided at the tip of the second catheter 122.

The third catheter 123 is a catheter that is inserted into a blood vessel, such as the radial artery, and is used to guide the first catheter 121 and the second catheter 122 within the blood vessel. The third catheter 123 has an inner diameter that allows the second catheter 122 to be inserted. The distal end of the third catheter 123 may be provided with a distal tip made of a radiopaque material. The proximal end of the third catheter 123 may be provided with a connector for inserting another catheter or injecting a contrast agent.

If the distal tip 100 of this embodiment is not fixed to the distal end of the shaft portion 151, the distal end 151a of the shaft portion 151 may get into the gap between the third catheter 123 and the second catheter 122, and the assembly 20 consisting of the combination of the embolus capture catheter and the first catheter 121 may not be able to be inserted into the main body portion 181 of the second catheter 122.

In addition, even if a tapered tip that gradually becomes thinner toward the tip side is fixed to the tip of the shaft portion 151, there is a risk that the tapered portion will get into the gap between the third catheter 123 and the second catheter 122.

On the other hand, when the tip tip 100 of this embodiment is fixed, the outer diameter of the front part 103 of the tip tip 100 is smaller than the inner diameter of the main body part 181 of the second catheter 122 and is larger than the difference between the inner diameter of the third catheter 123 and the outer diameter of the main body part 181, so that the tip 151a of the shaft part 151 can be prevented from entering the gap between the third catheter 123 and the second catheter 122. Then, the assembly 20 consisting of the combination of the embolus capture catheter and the first catheter 121 can be smoothly inserted into the main body part 181 of the second catheter 122.

The outer diameter of the front part 103 of the tip chip 100 needs only to be smaller than the inner diameter φ2i of the main body part 181 of the second catheter 122 and larger than the difference Δφ between the inner diameter φ3i of the third catheter 123 and the outer diameter φ2o of the main body part 181, but from the viewpoint of making it more difficult to enter a gap, it is preferably 2.1 times or more of Δφ, and more preferably 2.2 times or more. Also, from the viewpoint of reducing resistance inside the second catheter 122, it is preferably 95% or less of φ2i, and more preferably 90% or less.

The inner diameter of a typical guiding catheter is about 1.8 mm to 2.1 mm. The inner diameter of a support catheter is about 1.3 mm to 1.4 mm, and the outer diameter is about 1.5 mm to 1.7 mm. For this reason, the outer diameter of the front part 103 of the distal tip 100 is preferably 1.0 mm or more, more preferably 1.1 mm or more, from the viewpoint of making it difficult for the tip to enter a gap. The maximum outer diameter of the front part 103 is less than the inner diameter of the support catheter, but from the viewpoint of reducing resistance within the support catheter, it is preferably less than 1.25 mm, more preferably 1.2 mm or less. However, the outer diameter of the front part 103 can be appropriately selected according to the size of the catheter to be combined.

The length of the front part 103 is not particularly limited, but from the viewpoint of strength, it is preferable that it is somewhat longer, and it is preferable that it is longer than the outer diameter of the front part 103. On the other hand, from the viewpoint of reducing resistance inside the support catheter, it is preferably 5.0 mm or less, and more preferably 3.0 mm or less.

The front part can be cylindrical with a nearly constant outer diameter. However, from the standpoint of safety and to prevent the front part 103 from getting caught in a gap, it is preferable that the very tip of the front part 103 be a chamfered curved surface or a hemispherical shape so that no edges are formed.

By providing the intermediate section 101 which is thinner than the forward section 103, the insertion resistance can be reduced. The intermediate section 101 is required only to be thinner than the forward section 103 and thicker than the inner diameter of the first catheter 121, and it is preferable that the outer diameter is about 0.9 mm to 1.1 mm. From the viewpoint of safety, it is preferable that the boundary between the intermediate section 101 and the forward section 103 is connected smoothly without any steps. Also, from the viewpoint of strength, it is preferable that the intermediate section 101 does not decrease in diameter toward the tip side, and has a maximum outer diameter at the most forward section 103 side, so that no constriction occurs at the boundary between the intermediate section 101 and the forward section 103. In this case, the overall outer diameter of the intermediate section 101 may be constant, or the entire outer diameter may be gradually increased from the most rear section 102 side toward the forward section 103 side.

The rear section 102 only needs to be able to be inserted into the tip of the first catheter 121, and preferably has an outer diameter of about 0.7 mm to 1.0 mm. The rear section 102 may be tapered so that the diameter gradually decreases toward the base end, making it easier to insert into the tip of the first catheter 121. There are no particular limitations on the length of the rear section 102, but from the standpoint of ensuring reliable insertion into the first catheter 121, a length of about 2.0 mm to 5.0 mm is preferred.

Instead of providing the rear section 102, the intermediate section 101 may be gradually tapered toward the base end so that a portion of the base end of the intermediate section 101 can be inserted into the first catheter 121.

The total length of the distal tip 100 is not particularly limited, but from the viewpoint of preventing kinking of the shaft portion 151, it is preferable that the length is approximately the same as the length of the shaft portion 151 located on the distal side of the filter portion 152. Also, from the viewpoint of being able to advance the filter portion 152 to the more peripheral side of the blood vessel, it is preferable that the total length of the shaft portion 151 located on the distal side of the filter portion 152 is shorter, and accordingly, it is preferable that the total length of the distal tip 100 is also short to approximately the length of the shaft portion 151 located on the distal side of the filter portion 152.

When the difference between the inner diameter of the third catheter 123 and the outer diameter of the second catheter 122 was 0.5 mm, the shaft portion 151 to which the first evaluation tip 100, which has an outer diameter of 1.2 mm in the front portion 103, a length of 2.5 mm, an outer diameter of 1.0 mm in the middle portion 101, and a total length of 28 mm, was fixed, could be inserted without getting caught in the gap. On the other hand, in the case of the second evaluation tip shown in Figure 4, which has an outer diameter of 1.0 mm, a tapered portion 111 provided at a position 3.5 mm from the tip, and an outer diameter at the tip of 0.6 mm, getting caught occurred 6 times out of 10 times. In addition, in the case of the third evaluation tip shown in Figure 5, which has a straight portion 112 with a constant outer diameter of 1.2 mm over its entire length, getting caught in the gap did not occur, but the resistance when passing the second catheter 122 was large. In addition, when the outer diameter was constant at 1.0 mm, getting caught occurred, although to a lesser extent than the second evaluation tip. In the case of the fourth evaluation tip shown in Figure 6, which has a tapered section 111 that narrows toward the front and a spherical section 113 with a diameter of 1.2 mm, no snagging occurred in the gap, but during insertion, breakage occurred at the constricted section (diameter 0.6 mm) at the boundary between the front and middle sections, where the outer diameter rapidly decreases from the spherical section 113 toward the tapered section 111.

In the present embodiment, the distal tip 100 is fixed at a position where the distal end 151a of the shaft portion 151 protrudes further distally than the forward portion 103. This allows smooth advancement through the blood vessel. The protruding length of the shaft portion 151 is preferably 0.1 mm or more from the viewpoint of improving operability within the blood vessel. In addition, from the viewpoint of reducing the risk of getting caught in gaps, it is preferably 2.0 mm or less, more preferably 1.0 mm or less, and even more preferably 0.5 mm or less.

Table 1 shows the results of measuring whether the protruding length of the shaft portion 151 gets caught in the gap when the protruding length is changed. If the protruding length is 2.0 mm or less, the first catheter 121 housing the embolus capture catheter could be inserted without getting caught in the gap. On the other hand, if the protruding length is 3.0 mm or more, the tip of the shaft gets caught in the gap and the shaft breaks.

The distal tip 100 used in the measurement had an outer diameter of the front part 103 of 1.20 mm, an outer diameter of the middle part 101 of 1.00 mm, and a total length of 28 mm. The difference between the inner diameter of the third catheter 123 and the outer diameter of the second catheter 122 was 0.5 mm.

The tip tip 100 of this embodiment is preferably made of a resin that is highly flexible and resistant to bending fatigue. For example, it can be made of a polyether block amide copolymer.

In this embodiment, an example is shown in which the tip tip is fixed to the tip of an embolus capture catheter, but the tip tip of this embodiment is useful not only for embolus capture catheters, but also for other catheters that are delivered to a treatment site using a guiding catheter and a support catheter.

The tip of the present disclosure is useful in the field of catheters, as it facilitates smooth catheter delivery when delivering a catheter into a blood vessel using a guiding catheter and a support catheter.

10 Embolism capture catheter 20 Assembly 100 Distal tip 101 Middle section 102 Rear section 103 Front section 111 Tapered section 112 Straight section 113 Spherical section 121 First catheter 122 Second catheter 123 Third catheter 151 Shaft section 151a Distal section 152 Filter section 154A Contrast ring 161 Shaped section 162 Porous filter 171 Distal section 172 Base section 173 Connector section 174 Port section 181 Main body section 182 Base shaft 183 Protective member

Claims (9)

a shaft portion that is inserted into an inner cavity of a delivery catheter that is guided to an affected area using a guiding catheter and a support catheter that is inserted into the guiding catheter ;
a tip fixed to a tip end of the shaft portion ,
The tip is
A middle part,
a front portion that is in contact with the intermediate portion and is provided on the most distal side of the distal tip , the front portion having a larger diameter than the intermediate portion;
the intermediate section has a diameter larger than an inner diameter of the delivery catheter and a length longer than the forward section;
A catheter, wherein a tip of the shaft portion protrudes toward the tip side of the front portion. The catheter according to claim 1 , wherein the tip of the shaft portion protrudes from the tip of the front portion by 0.1 mm or more and 2 mm or less. The tip according to claim 1 or 2, wherein the length of the front portion is longer than the outer diameter of the front portion. The catheter according to any one of claims 1 to 3, wherein the intermediate section has a maximum outer diameter on the front section side. The catheter according to any one of claims 1 to 3, wherein the intermediate section has a constant outer diameter. The catheter according to any one of claims 1 to 5, wherein the intermediate section and the front section are smoothly connected without any steps. Further comprising a rear portion provided on the base end side relative to the intermediate portion,
The catheter according to any one of claims 1 to 6 , wherein the rear portion has a diameter smaller than an inner diameter of the delivery catheter. The catheter according to any one of claims 1 to 7 , wherein the shaft portion has a filter portion for capturing emboli, the filter portion being spaced apart from the base end of the distal tip. A catheter according to any one of claims 1 to 8;
The guiding catheter;
The support catheter;
The delivery catheter,
A catheter system, wherein the front section has a diameter smaller than the inner diameter of the support catheter and larger than the difference between the inner diameter of the guiding catheter and the outer diameter of the support catheter.

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