Catheter Tips

Abstract

To provide a catheter which can be easily inserted into a support catheter in delivering the catheter into a blood vessel by using a guiding catheter and the support catheter.SOLUTION: A leading-end tip 100 comprises an intermediate portion 101 and a front portion 103 that is positioned on the leading end side of the intermediate portion 101. The diameter of the front portion 103 is larger than the diameter of the intermediate portion 101 but smaller than the inner diameter of the support catheter. The diameter of the front portion 103 is larger 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. The leading end of a shaft portion 151 protrudes on the leading end side of the front portion 103.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a catheter distal tip that is secured to the distal end of a catheter, and to a catheter having a secured distal tip. [Background technology]

[0002] In a treatment for widening a narrowed portion of a blood vessel, such as percutaneous coronary intervention (PCI), a balloon catheter for widening the narrowed portion to be treated is placed at the narrowed portion 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 a stent is guided to the narrowed portion through the guiding catheter.

[0003] In a treatment for widening a narrowed portion of a blood vessel, such as PCI, a filter for capturing emboli to capture thrombi and the like scattered by the treatment may be placed distal to the treatment site where a balloon catheter for widening the narrowed treatment site is placed. 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). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-30035 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is very difficult to guide the embolus capture catheter to the distal side of the treatment site by operating the distal guide wire, and depending on the blood vessel course, it may not be possible to guide the embolus capture catheter to the distal side of 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.

[0006] On the other hand, when guiding a device to a narrow 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.

[0007] The inventors of the present application have considered using a support catheter in combination with the guiding catheter for emboli capture. However, it has become clear that when the emboli capture catheter is inserted into the tube portion of the support catheter, the coiled tip of the catheter is not inserted correctly into the support catheter, and the catheter easily becomes caught in the gap between the guiding catheter and the support catheter.

[0008] It should be noted that such problems are not limited to embolus capturing catheters, but may occur in any catheter that is guided into a blood vessel using a guiding catheter and a support catheter.

[0009] An object of the present disclosure is to make it possible to easily insert a catheter into a support catheter when guiding a catheter into a blood vessel using a guiding catheter and a support catheter. [Means for solving the problem]

[0010] One aspect of the tip tip of the present disclosure is fixed to the tip of a shaft portion that is guided to an affected area using a guiding catheter and a support catheter inserted into the guiding catheter, and comprises an intermediate portion and a forward portion that is located distal to the intermediate portion, has a larger diameter than the intermediate portion, 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 tip of the shaft portion protrudes toward the distal side of the forward portion.

[0011] In one embodiment of the tip tip, by fixing it to the tip of the shaft of the 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, thereby making it possible to guide the catheter smoothly.

[0012] 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.

[0013] In one embodiment of the tip, the length of the front portion can be greater than the outer diameter of the front portion, which can make it less likely to get caught in a gap.

[0014] In one embodiment of the tip, the intermediate portion may have a maximum outer diameter at the front portion side, so that no significant constriction occurs between the intermediate portion and the front portion, improving the strength of the tip and preventing it from breaking between the intermediate portion and the front portion.

[0015] One embodiment of the tip may further include 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 having a diameter smaller than the inner diameter of the delivery catheter. In this way, a part of the base end side of the tip can be housed in the delivery catheter, and the tip and the delivery catheter are integrated to prevent kinking on the base end side of the tip, and the tip can be well tracked even in meandering blood vessels, further improving operability.

[0016] One aspect of the embolus capture catheter of the present disclosure includes the distal tip of the present disclosure and a shaft portion to which the distal tip is fixed, the shaft portion having a filter portion for embolus capture spaced 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. Effect of the Invention

[0017] According to the distal tip of the present disclosure, when a catheter is guided into a blood vessel using a guiding catheter and a support catheter, the catheter can be smoothly guided. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing an embolus capture catheter according to one embodiment. [Diagram 2] FIG. 2 is a perspective view showing the state in which the embolus capturing catheter is set in the delivery catheter. [Diagram 3] 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. [Figure 4] 13 is a photograph showing a second tip for evaluation. [Diagram 5] 13 is a photograph showing a third tip for evaluation. [Figure 6]13 is a photograph showing a fourth tip for evaluation. [Figure 7] FIG. 2 is a perspective view showing a distal tip according to one embodiment. [Figure 8] FIG. 2 is a plan view showing a tip according to one embodiment. [Figure 9] FIG. 2 is a diagram showing an end face on the distal end side of a distal tip according to one embodiment. [Figure 10] FIG. 2 is a diagram showing an end face on the base end side of a distal tip according to one embodiment. [Figure 11] 10 is a cross-sectional view taken along line XI-XI in FIG. 9. [Figure 12] 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. [Figure 13] 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. [Figure 14] 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. [Figure 15] 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. [Figure 16] FIG. 2 is a right side view showing the filter portion of the embolus capture catheter according to one embodiment in a housed state. [Figure 17] FIG. 2 is a plan view showing a state in which a filter portion of an embolus capturing catheter according to one embodiment is deployed. [Figure 18] 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. [Figure 19] FIG. 2 is a rear view showing the filter portion of the embolus capture catheter according to one embodiment in a deployed state. [Figure 20] FIG. 2 is a left side view showing the filter portion of the embolus capture catheter according to one embodiment in a deployed state. [Figure 21] 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] 1 and 12 to 21, the distal tip 100 of this embodiment is fixed to the distal end of a shaft portion 151 such that a distal end 151a of the shaft portion 151 protrudes toward the distal end side. The distal tip 100 has an intermediate portion 101, a rear portion 102 that is provided 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 provided 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.

[0020] 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 shaft for a normal catheter 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 a blood vessel. On the base end side of the shaft portion 151 from the tip tip 100, a filter portion 152 is formed having 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.

[0021] As shown in FIG. 2, the shaft portion 151 constituting the embolus capturing 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 in a state where the first catheter 121 is 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 capturing catheter 10 to a lesion site. The tip of the first catheter 121 may be provided with a reinforcing braid.

[0022] As shown in Figs. 7 to 11, in this embodiment, the outer diameter of the rear part 102 of the distal tip 100 is smaller than the inner diameter of the distal side part 171 of the first catheter 121, and the outer diameter of the intermediate part 101 is larger than the inner diameter of the distal side part 171 of the first catheter 121. When the base end of the shaft part 151 is inserted from the distal side of the first catheter 121, as shown in Fig. 12, the filter part 152, the honeycomb pipes 154A and 154B, and the rear part 102 of the distal tip 100 are accommodated in the first catheter 121, and the intermediate part 101 and the front part 103 of the distal tip 100 and the distal end 151a of the shaft part 151 are exposed from the distal end 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.

[0023] As shown in Fig. 3, an assembly 20 formed by combining the embolus capturing catheter 10 and a first catheter 121 is inserted into a second catheter 122, which is a support catheter, and a 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.

[0024] After use, the embolus capture catheter 10 can be retrieved by storing the filter portion 152 in a retrieval catheter having 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 (the 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.

[0025] 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-layered 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.

[0026] The third catheter 123 is a catheter that is inserted into a blood vessel such as the radial artery, and guides 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. A distal tip made of a radiopaque material can be provided at the distal end of the third catheter 123. A connector can be provided at the proximal end of the third catheter 123 for inserting another catheter or injecting a contrast agent.

[0027] If the tip tip 100 of this embodiment is not fixed to the tip of the shaft portion 151, the tip 151a of the shaft portion 151 may get into the gap between the third catheter 123 and the second catheter 122, making it possible that the assembly 20 consisting of the embolism capture catheter and the first catheter 121 cannot be inserted into the main body portion 181 of the second catheter 122.

[0028] In addition, even if a tapered tip 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.

[0029] On the other hand, when the distal tip 100 of this embodiment is fixed, the outer diameter of the front part 103 of the distal 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 it is possible to prevent the distal end 151a of the shaft part 151 from entering the gap between the third catheter 123 and the second catheter 122. Then, the assembly 20 formed by combining the embolus capturing catheter and the first catheter 121 can be smoothly inserted into the main body part 181 of the second catheter 122.

[0030] The outer diameter of the front part 103 of the tip chip 100 should 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.

[0031] The inner diameter of a normal 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 preventing the tip from entering 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.

[0032] The length of front portion 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 front portion 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.

[0033] The front part may be cylindrical with a substantially constant outer diameter. However, from the standpoint of safety and to prevent the tip of the front part 103 from getting caught in a gap, it is preferable that the tip be chamfered to have a curved surface or a hemispherical shape so that no edges are formed.

[0034] By providing the intermediate section 101 which is thinner than the forward section 103, the insertion resistance can be reduced. The intermediate section 101 may be thinner than the forward section 103 and may be thicker than the inner diameter of the first catheter 121, and the outer diameter is preferably 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 step. From the viewpoint of strength, it is preferable that the intermediate section 101 does not decrease in diameter toward the tip side and has the largest 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 outer diameter of the entire intermediate section 101 may be constant, or may be gradually increased in diameter from the most rear section 102 side toward the forward section 103 side.

[0035] 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, so that it can be easily inserted into the tip of the first catheter 121. The length of the rear section 102 is not particularly limited, but is preferably about 2.0 mm to 5.0 mm from the viewpoint of ensuring reliable insertion into the first catheter 121.

[0036] Instead of providing the rear portion 102, the intermediate portion 101 may be gradually tapered toward the base end so that a portion of the base end side of the intermediate portion 101 can be inserted into the first catheter 121.

[0037] 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 it is approximately the same as the length of the shaft portion 151 located on the distal side of the filter portion 152. Furthermore, 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.

[0038] 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 part 151 to which the first evaluation tip 100, which has an outer diameter of 1.2 mm in the front part 103, a length of 2.5 mm, an outer diameter of 1.0 mm in the middle part 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 FIG. 4, which has an outer diameter of 1.0 mm, a tapered part 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 FIG. 5, which has a straight part 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 portion 111 that narrows toward the front and a spherical portion 113 with a diameter of 1.2 mm, no jamming occurred in the gap, but during insertion, breakage occurred at the narrowed portion (diameter 0.6 mm) at the boundary between the front and middle portions, where the outer diameter rapidly decreases from the spherical portion 113 toward the tapered portion 111.

[0039] In the distal tip 100 of this embodiment, the distal end 151a of the shaft portion 151 is fixed at a position where it 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. Also, 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.

[0040] Table 1 shows the results of measuring whether or not 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 capturing 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.

[0041] [Table 1]

[0042] The distal tip 100 used in the measurement had an outer diameter of 1.20 mm at the front portion 103, an outer diameter of 1.00 mm at the middle portion 101, 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.

[0043] The tip 100 of this embodiment is preferably made of a resin having excellent flexibility and resistance to bending fatigue, for example, a polyether block amide copolymer.

[0044] In this embodiment, an example has been 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 fed to a treatment site using a guiding catheter and a support catheter. [Industrial Applicability]

[0045] INDUSTRIAL APPLICABILITY The distal tip of the present disclosure is useful in the field of catheters, since it enables smooth catheter delivery when a catheter is delivered into a blood vessel using a guiding catheter and a support catheter. [Explanation of symbols]

[0046] 10 Embolism capture catheter 20 assembly 100 Tip 101 Middle section 102 Posterior part 103 Front 111 Tapered section 112 Straight section 113 Spherical part 121 First Catheter 122 Second Catheter 123 Third Catheter 151 Shaft section 151a Tip 152 Filter section 154A Contrast Ring 161 Shabu 162 Porous Filter 171 Tip side 172 Base end side 173 Connector part 174 Port section 181 Main body part 182 Base end shaft 183 Protective materials

Claims

1. 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 provided on the most distal side of the distal tip in contact with the intermediate portion, 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.

2. 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.

3. The tip of claim 1 or 2, wherein the length of the front portion is greater than the outer diameter of the front portion.

4. 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.

5. A catheter described in any one of claims 1 to 3, wherein the intermediate portion has a constant outer diameter.

6. A catheter described in any one of claims 1 to 5, wherein the intermediate portion and the front portion are smoothly connected without any steps.

7. 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.

8. A catheter as described in any one of claims 1 to 7, wherein the shaft portion has a filter portion for capturing emboli, spaced apart from the base end of the distal tip.

9. 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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