JP2013188309A - Stent extending balloon, balloon catheter, and stent delivery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent extending balloon capable of extending a stent while suppressing the over-extension of the exposed part from the stent.SOLUTION: Reinforced parts 26 having larger strength with respect to extension than the central part of a balloon 14 are formed to both end parts of balloon 14 so as to be overlapped with a stent mounting region 23 by the adhesion of a plurality of reinforced fibers 25 and the abnormal over-extension of the exposed region 24 at the time of extension of the balloon 14 is suppressed.

Description

The present invention relates to a balloon for expanding a stent, and more particularly to a balloon for expanding a stent inserted into a living body lumen.
The present invention also relates to a balloon catheter using a stent expansion balloon and a stent delivery system.

When a lesion such as a stenosis or occlusion occurs in a biological lumen such as a blood vessel, bile duct, trachea, esophagus, or urethra, the stent expands the stenosis or occlusion, and expands the expanded lumen. It is a tubular medical device that is left in place for securing.
The stent is inserted into the lesioned part in a contracted state and is expanded at the lesioned part to increase the diameter, thereby securing the lumen. By the means of expansion, a self-expanding stent having its own expansion function and The balloon is broadly classified into a balloon expandable stent in which a balloon is expanded in the stent and the stent is expanded by the expansion force of the balloon.
Among these, as shown in FIG. 11, the balloon-expandable stent needs to be inserted into the living body lumen by positioning the balloon 2 in the stent 1 having a reduced diameter. There is a demand for a reduction in diameter during contraction.

  For example, Patent Document 1 proposes a balloon in which an elastic body excellent in stretchability is used as a material so that the balloon is deflated without being wrapped around a catheter shaft. In this balloon, the diameter at the time of contraction can be reduced by the bulk due to wrapping.

JP-A-10-15055

On the other hand, in the balloon for stent expansion, in order to expand the tubular stent 1 over the entire length, a balloon 2 longer than the stent 1 is used, and exposed portions 3 exposed from the stent 1 need to be formed at both ends of the balloon 2. There is.
For this reason, when the stent 1 is mounted on a balloon excellent in stretchability proposed in Patent Document 1 and the stent 1 is to be expanded, the exposed portion 3 not covered with the stent 1 as shown in FIG. May be abnormally overexpanded to a diameter larger than that of the stent 1, and may cause a load on a normal living body lumen around the lesion and damage it.

The present invention has been made to solve such a conventional problem, and provides a stent expansion balloon capable of expanding a stent while suppressing overexpansion of an exposed portion exposed from the stent. Objective.
Another object of the present invention is to provide a balloon catheter and a stent delivery system using such a balloon for stent expansion.

  The stent expansion balloon according to the present invention is a stent expansion balloon in which a stent is mounted on the outer periphery of a stent mounting region in the center in the axial direction and expandable in accordance with a change in pressure in the expansion chamber, and is disposed at both end portions. And a reinforcing portion having a greater strength against expansion than the central portion, the reinforcing portion overlapping the stent mounting region.

The central portion is preferably formed from a first elastic member that elastically expands and contracts according to the pressure in the expansion chamber.
In this case, the reinforcing portion can be formed from a member in which reinforcing fibers are fixed to the first elastic member.
Alternatively, the reinforcing portion can be formed from a second elastic member having a strength greater than that of the first elastic member. In this case, the second elastic member may be made of the same material as the first elastic member and thicker than the first elastic member, or another elastic layer may be provided on the first elastic member. It may be formed by joining to form a two-layer structure.

The balloon catheter according to the present invention includes a long shaft main body having a balloon expansion lumen formed therein, and the above stent expansion balloon attached to the shaft main body so that the expansion chamber communicates with the balloon expansion lumen. It is equipped with.
A stent delivery system according to the present invention includes the above-described balloon catheter and a stent mounted on the outer periphery of a stent mounting region of a stent expansion balloon.

  According to the present invention, the reinforcing portions having greater strength with respect to expansion than the central portion are disposed at both end portions and overlap the stent mounting region, so that overexpansion of the exposed portion exposed from the stent is suppressed. However, the stent can be expanded.

It is a side view which shows the whole structure of the stent delivery system which concerns on Embodiment 1 of this invention. FIG. 3 is a side view showing a structure near the balloon of the balloon catheter used in the first embodiment. It is the sectional view on the AA line of FIG. FIG. 3 is a partially enlarged cross-sectional view showing a structure inside the balloon of the balloon catheter used in the first embodiment. FIG. 3 is a side view showing the structure in the vicinity of the balloon when the balloon catheter used in Embodiment 1 is expanded. FIG. 6 is a partial enlarged cross-sectional view showing a structure of a reinforced portion of a stent expansion balloon used in a modification of the first embodiment. FIG. 10 is a partial enlarged cross-sectional view showing a structure of a reinforced portion of a balloon for stent expansion used in another modification of the first embodiment. FIG. 6 is a side view showing a structure in the vicinity of a balloon of a balloon catheter used in Embodiment 2. FIG. 10 is a partially enlarged cross-sectional view showing a structure inside a balloon of a balloon catheter used in a modification of the second embodiment. FIG. 10 is a partial enlarged cross-sectional view showing a structure inside a balloon of a balloon catheter used in another modification of the second embodiment. It is a side view which shows the mode of the balloon vicinity of the conventional stent delivery system at the time of balloon contraction. It is a side view which shows the mode of the balloon vicinity of the conventional stent delivery system at the time of balloon expansion.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1
FIG. 1 shows the overall structure of the stent delivery system according to the first embodiment. The stent delivery system includes a balloon catheter 11 and a balloon expandable stent 12 attached to the balloon catheter 11.
The balloon catheter 11 includes a long shaft main body 13, and an expandable stent expansion balloon 14 is disposed on the outer peripheral portion in the vicinity of the distal end portion of the shaft main body 13, while a branch hub is provided at the base end portion of the shaft main body 13. 15 is attached. The shaft body 13 and the balloon 14 are inserted into biological lumens such as blood vessels, bile ducts, trachea, esophagus, and urethra during treatment, and a guide wire 16 is inserted into the shaft body 13 so as to advance and retreat. . The branching hub 15 is used to inject / suck the expansion fluid into the balloon 14 via the operation port 17 for moving the guide wire 16 inserted into the shaft body 13 forward and backward, and the inside of the shaft body 13. The fluid port 18 is provided.
The stent 12 is attached to the outer peripheral portion of the balloon 14.

As shown in FIG. 2, the shaft body 13 has a double tube structure including an outer tube 19 and an inner tube 20 inserted into the outer tube 19, and an outer peripheral surface of the inner tube 20 and an outer tube. A balloon-expanding lumen 21 is formed between the inner peripheral surface 19 and the inner peripheral surface 19.
The inner tube 20 has a front extending portion 20a that extends forward from the distal end portion of the outer tube 19, that is, a front extending portion 20a. The distal end portion of the balloon 14 is disposed on the outer periphery of the front extending portion 20a of the inner tube 20. In addition to being joined, the base end of the balloon 14 is joined to the outer periphery near the distal end of the outer tube 19, so that an expansion chamber communicating with the balloon expansion lumen 21 is formed inside the balloon 14.

The balloon 14 is made of an elastic member 22 that elastically expands and contracts in response to the pressure in the expansion chamber, and is configured to be wound around the shaft body 13 without being wrapped. The balloon 14 formed of such a material is called a high compliant balloon. The balloon 14 may be wrapped around the shaft body 13 for wrapping.
Further, the balloon 14 has a longer overall length than the stent 12 in order to expand the stent 12 evenly over the entire length, and both ends of the stent mounting region 23 are centered on the stent mounting region 23 to which the stent 12 is mounted. An exposed region 24 that is exposed from the stent 12 is formed on each side.

  Further, a plurality of reinforcing fibers 25 are respectively fixed to the elastic members 22 forming both end portions of the balloon 14, thereby forming a reinforced portion 26 having greater strength against expansion than the central portion of the balloon 14. . As a result, the balloon 14 has a high compliant property at the central portion, and the reinforced portions 26 at both end portions are low compliant or non-compliant. The reinforcing portion 26 on the distal end side is formed in the region of the balloon 14 from the distal end portion of the balloon 14 joined to the outer periphery of the forward extension portion 20a of the inner tube 20 to the point P1 that slightly enters the stent attachment region 23. The reinforced portion 26 at the proximal end is formed in a region from the proximal end of the balloon 14 joined to the outer periphery of the outer tube 19 to a point P2 that slightly enters the stent attachment region 23. That is, both of the reinforcing portions 26 overlap the stent mounting region 23, respectively.

The plurality of reinforcing fibers 25 respectively extend along the longitudinal direction of the balloon 14 and are arranged at equal intervals in the circumferential direction of the balloon 14 as shown in FIG.
Further, as shown in FIG. 4, the reinforcing fiber 25 is arranged so as to extend from the joint portion between the balloon 14 and the outer tube 19 or the inner tube 20 to the inside of the stent mounting region 23.
FIG. 4 shows an expansion chamber 27 of the balloon 14 communicating with a balloon expansion lumen 21 formed between the outer tube 19 and the inner tube 20. Contrastable markers 28 are arranged in the vicinity of the distal end portion and the proximal end portion of the stent 12 inside the expansion chamber 27 and on the outer periphery of the forward extension portion 20a of the inner tube 20. These contrast markers 28 are for grasping the position of the stent 12 inserted into the living body lumen from the outside of the living body by X-ray contrast.

The material for forming the outer tube 19 and the inner tube 20 of the shaft body 11 is preferably a material having a certain degree of flexibility, such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and the like. Thermoplastic resins such as polyolefin, polyvinyl chloride, polyurethane, polyamide, polyamide elastomer, polyimide, silicone resin, polyether / etherketone, and polyester elastomer can be used.
Moreover, as a forming material of the elastic member 22 excellent in stretchability for forming the balloon 14, an elastic body such as a thermoplastic elastomer such as a rubber material or a polyamide elastomer can be used.

As the reinforcing fibers 25, various fibers having high strength such as glass fibers, carbon fibers, and aromatic polyamide resin fibers can be used. For example, as shown in FIG. Evenly arranged in the direction.
Further, the contrast marker 28 can be formed of a material that can be easily recognized by X-ray contrast, such as gold, platinum, iridium, tungsten, or an alloy thereof, or a silver-palladium alloy.

  The material for forming the stent 12 is preferably a material having a certain degree of biocompatibility, such as stainless steel, tantalum or tantalum alloy, platinum or platinum alloy, gold or gold alloy, cobalt nickel alloy, cobalt chrome alloy, titanium alloy, Metal materials such as niobium alloys are conceivable. Moreover, after producing a stent shape with a metal material, you may give noble metal plating, such as gold | metal | money and platinum. As stainless steel, SUS316L having the most corrosion resistance is suitable.

Next, the operation of the first embodiment will be described.
First, in a state where the stent 12 is mounted on the outer peripheral portion of the stent mounting region 23 of the balloon 14, the guide wire 16 inserted into the inner tube 20 of the shaft body 13 from the operation port 17 is inserted from the distal end portion of the inner tube 20. The balloon catheter 11 is protruded forward, and the balloon catheter 11 is inserted into a living body lumen such as a blood vessel using the guide wire 16 as a guide. At this time, it is assumed that the expansion fluid is not injected into the expansion chamber 27 of the balloon 14 and the balloon 14 is in a contracted state. Further, the position of the stent 12 in the living body lumen is confirmed by recognizing the contrast marker 28 disposed in the expansion chamber 27 of the balloon 14 by performing X-ray contrast.

  When it is confirmed that the stent 12 is positioned at a lesion requiring treatment, the insertion operation of the balloon catheter 11 is terminated. Here, the expansion chamber 27 of the balloon 14 is passed from the fluid port 18 through the balloon expansion lumen 21. An expansion fluid is injected into the interior. As the expansion fluid is injected, the balloon 14 is expanded while expanding the stent 12 mounted on the outer periphery of the stent mounting region 23 as shown in FIG.

At this time, the exposed regions 24 at both ends of the balloon 14 are exposed from the stent 12 without being covered with the stent 12, but are reinforced by the reinforcing fibers 25 across the exposed region 24 into the stent mounting region 23. Since the reinforced portion 26 is formed and has a greater strength against expansion than the central portion of the balloon 14, the exposed portion 24 is prevented from being abnormally overexpanded to a diameter larger than that of the stent 12. Is done.
In this manner, the stent 12 is expanded to the target diameter while confirming the injection pressure of the expansion fluid. Thereby, the stenosis part or the obstruction | occlusion part which is a lesion part can be expanded, without applying a load to the normal biological lumen part around a lesion part resulting from the overexpansion of the balloon 14.

When the stent 12 is expanded to the target diameter, the balloon 14 is contracted by sucking the expansion fluid from the expansion chamber 27 of the balloon 14 through the balloon expansion lumen 21, and the balloon 12 is left in place while the stent 12 is left in place. The catheter 11 is pulled out from the living body lumen.
Note that the portion of the balloon 14 other than the reinforcing portion 26, that is, the central portion of the balloon 14 is composed of only the elastic member 22 and is not reinforced by the reinforcing fiber 25. Therefore, the balloon 14 is highly flexible and flexible. The catheter 11 can be smoothly inserted into the living body lumen.

Since the exposed portion 24 of the balloon 14 may directly contact the inner wall of the living body lumen, the reinforcing fiber 25 in the reinforcing portion 26 is not fixed on the outer surface of the elastic member forming the balloon 14, As shown in FIG. 4, it is desirable that the elastic member is embedded in the elastic member or fixed on the inner surface of the elastic member.
For example, as shown in FIG. 6, the elastic member forming the balloon 14 has a two-layer structure in which an inner layer 29 and an outer layer 30 are joined, and reinforcing fibers 25 can be embedded between the inner layer 29 and the outer layer 30. . At this time, as shown in FIG. 7, it is more preferable that the outer surface of the outer layer 30 is smooth without being raised corresponding to the embedded position of the reinforcing fiber 25.

In the first embodiment, the eight reinforcing fibers 25 are evenly arranged in the circumferential direction of the balloon 14. However, the present invention is not limited to this, and fewer than eight reinforcing fibers 25 or nine or more reinforcing fibers 25 are provided. It can also be used. However, if the number of the reinforcing fibers 25 is too small, the elastic member between the reinforcing fibers 25 adjacent to each other may be abnormally overexpanded. If the number of the reinforcing fibers 25 is too large, the expandability of the balloon 14 is impaired. As a result, the stent 12 may not be expanded evenly over the entire length. Therefore, about eight are preferable as in the first embodiment.
In Embodiment 1 described above, the elongated reinforcing fibers 25 extending along the longitudinal direction of the balloon 14 are used. However, the balloon can also be obtained by dispersing a large number of fine reinforcing fibers in the elastic member 22. It is possible to form the reinforced portion 26 having a greater strength against expansion than the central portion of the 14.

Embodiment 2
In the first embodiment, the reinforcing portion 26 is formed by fixing the reinforcing fiber 25 to the elastic member 22 constituting the balloon 14, but the present invention is not limited to this, and the stent expansion balloon 34 shown in FIG. As described above, the reinforcing portion 26 may be formed by the second elastic member 36 having a strength higher than that of the first elastic member 35 constituting the central portion of the balloon.
As the second elastic member 36, for example, an elastic body made of a different material having a larger elastic modulus than the first elastic member 35 can be used.
As described above, even if the entire reinforced portion 26 is configured by the second elastic member 36 having high strength, the stent 12 is expanded while suppressing the overexpansion of the exposed portion 24 as in the first embodiment. It becomes possible.

Instead of using a different material from the first elastic member 35 as the second elastic member 36, the first elastic member is made of the same material as the first elastic member 35 as shown in FIG. What was formed more thickly than 35 can also be used. Even if it is the same material, the 2nd elastic member 36 which has intensity | strength larger than the 1st elastic member 35 is formed by making it thick.
Further, as shown in FIG. 10, the second elastic member 36 may be formed by joining another elastic layer 37 to the first elastic member 35 to form a two-layer structure. The elastic layer 37 can be made of the same material as the first elastic member 35 or can be made of a different material.

  In the first and second embodiments described above, the so-called over-the-wire balloon catheter 11 in which the guide wire 16 is inserted from the proximal end portion to which the branch hub 15 is attached to the distal end portion is used. Similarly, the present invention can also be applied to a stent delivery system using a so-called rapid exchange type balloon catheter in which a guide wire is passed only through the guide wire.

  11 balloon catheter, 12 stent, 13 shaft body, 14, 34 stent expansion balloon, 15 branch hub, 16 guide wire, 17 operation port, 18 fluid port, 19 outer tube, 20 inner tube, 21 balloon expansion lumen , 22 Elastic member, 23 Stent mounting region, 24 Exposed region, 25 Reinforcing fiber, 26 Reinforcing part, 27 Expansion chamber, 28 Contrast marker, 29 Inner layer, 30 Outer layer, 35 First elastic member, 36 Second elastic member 37 Elastic layer, 20a Front extension part.

Claims (8)

A stent expansion balloon in which a stent is mounted on the outer periphery of a stent mounting region in the center in the axial direction and expandable according to a change in pressure in the expansion chamber,
It is provided with a reinforcing portion that is disposed at both end portions and has a greater strength against expansion than the central portion,
The stent expansion balloon according to claim 1, wherein the reinforcing portion overlaps the stent mounting region.   The stent expansion balloon according to claim 1, wherein the central portion is formed of a first elastic member that elastically expands and contracts in response to pressure in the expansion chamber.   The stent expansion balloon according to claim 2, wherein the reinforcing portion is made of a reinforcing fiber fixed to the first elastic member.   The stent expansion balloon according to claim 2, wherein the reinforcing portion is formed of a second elastic member having a strength greater than that of the first elastic member.   The stent expansion balloon according to claim 4, wherein the second elastic member is formed of the same material as the first elastic member and is thicker than the first elastic member.   The stent expansion balloon according to claim 4, wherein the second elastic member is formed by joining another elastic layer to the first elastic member to form a two-layer structure. A long shaft body with a balloon expansion lumen formed inside;
A balloon catheter comprising the stent expansion balloon according to any one of claims 1 to 6, wherein the expansion chamber is attached to the shaft body so as to communicate with the balloon expansion lumen. . A balloon catheter according to claim 7;
A stent delivery system comprising: a stent attached to an outer periphery of the stent attachment region of the stent expansion balloon.

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