JP2016112388A - Stent delivery catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent delivery catheter with a new structure capable of placing a stent by uniform diameter reduction when a stent with many waves is to be set on a balloon.SOLUTION: A balloon 12 is set at the distal end part of a shaft 24, a stent 14 is set on the balloon 12, and the stent 14 has a skeletal structure extending in a circumferential direction by folding in an axial direction concerning a stent delivery catheter 10. A large diameter part 42 having an outer diameter dimension larger than that of a proximal end side adjacent part 40 in a placement portion is arranged in the placement portion of the stent 14 in the shaft 24.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a stent delivery catheter for delivering a stent to a stenosis site in a lumen, and more particularly to a stent delivery catheter for delivering a stent having a high wave number.

  Conventionally, when an abnormality such as stenosis or occlusion occurs in a lumen such as a blood vessel, the stent is delivered to a lesioned portion in the lumen by, for example, a stent delivery catheter. Then, stent treatment is performed in which the stent is expanded and pressed against the lumen wall to hold the lumen in an expanded state. The stent has a small diameter when inserted into the lumen, but is expanded and placed in the lumen. As a method for expanding the diameter of the stent in the lumen, there are self-expansion using a shape memory material and mechanical expansion, and expansion using a balloon.

  That is, when the stent is expanded by a balloon, extrapolation is performed with the balloon folded against the distal end portion of the shaft, as in a stent delivery catheter described in JP 2014-61191 A (Patent Document 1). At the same time, the stent is extrapolated and attached to the folded balloon to reduce the diameter. Then, by inserting the distal end portion of the stent delivery catheter into the lesioned part in the lumen and expanding the balloon, the stent extrapolated to the balloon is expanded in diameter and pressed against the lumen wall. Thereafter, the stent is placed in the lumen by deflating the balloon and withdrawing the catheter.

  By the way, as the stent to be placed in the lumen, for example, a skeletal stent or the like in which one linear body extends continuously in a spiral or cylindrical shape in the circumferential direction while being folded back in the axial direction is used. For example, when the stent is placed in a thick lumen or the like, a stent that has a large wave number (number of bent portions) in the circumferential direction and expands greatly when the diameter is expanded is preferably used.

  On the other hand, the balloon attached to the distal end portion of the stent delivery catheter is preferably a balloon having a small film thickness in order to ensure flexibility of the catheter distal end portion.

  However, since a balloon having a small film thickness has a small outer diameter when folded, when a stent having a large wave number is externally attached and subjected to a diameter reduction process, the stent may not be uniformly reduced in diameter. Specifically, the struts adjacent in the circumferential direction of the stent may partially overlap. In addition, this may cause a problem that the stent does not expand uniformly when the balloon is expanded to expand the diameter of the stent.

JP 2014-61191 A

  The present invention has been made in the background of the above-mentioned circumstances. The problem to be solved is to reduce the diameter of the stent uniformly even when the stent is mounted on the balloon, particularly when the stent having a high wavenumber is mounted. It is an object of the present invention to provide a stent delivery catheter having a novel structure that can be attached to a patient.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

  According to a first aspect of the present invention, a balloon is attached to a tip portion of a shaft, a stent is attached to the balloon, and the stent has a skeletal structure extending in the circumferential direction while being folded back in the axial direction. In the stent delivery catheter, the stent mounting portion of the shaft is provided with a large-diameter portion whose outer diameter is larger than the proximal end side adjacent portion of the mounting portion. It is.

  According to the stent delivery catheter having a structure according to this aspect, since the large-diameter portion is provided in the stent mounting portion of the shaft, the outer diameter of the balloon at the time of folding is set regardless of the film thickness of the balloon. It becomes possible to set appropriately according to the outer diameter dimension of a large diameter part. Thereby, for example, even when a balloon having a thin film thickness and a stent having a large wave number are simultaneously employed, it is possible to prevent the outer diameter of the balloon when folded from becoming too small compared to the inner diameter of the stent when contracted. Therefore, even when the stent is reduced in diameter and mounted on the balloon, a non-uniform reduction in diameter such as excessively reducing the diameter of the stent and overlapping the struts can be effectively avoided.

  According to a second aspect of the present invention, in the stent delivery catheter according to the first aspect, the outer diameter of the large-diameter portion is attached to the outer peripheral surface of the shaft main body so that the shaft member is attached. It is made larger than the outer diameter dimension of the proximal end side adjacent part of the said mounting part in a main body.

  According to the stent delivery catheter structured according to the present aspect, the outer diameter of the large-diameter portion is attached to the outer peripheral surface of the shaft main body, so that the proximal end of the stent mounting portion in the shaft main body is obtained. Since it is larger than the outer diameter of the side adjacent portion, the large diameter portion can be formed with a simple structure.

  According to a third aspect of the present invention, in the stent delivery catheter according to the second aspect, the hardness of the covering member is smaller than the hardness of the shaft body.

  According to the stent delivery catheter having the structure according to this aspect, the hardness of the covering member is smaller than the hardness of the shaft body, so that the flexibility at the distal end portion of the stent delivery catheter can be ensured satisfactorily. In addition, although the material of a coating | coated member is not limited at all, synthetic resins, such as a polyamide elastomer, a polyester elastomer, and a polyurethane, can be employ | adopted suitably.

  In addition, as a shape of the large diameter part of the stent delivery catheter concerning this invention, the following aspects can be employ | adopted suitably, for example. That is, the fourth aspect of the present invention is the stent delivery catheter according to any one of the first to third aspects, wherein the outer diameter of the large-diameter portion is constant throughout. It is.

  According to the stent delivery catheter structured according to this aspect, since the outer diameter of the large-diameter portion is constant throughout, the support surface of the folded balloon is a circumferential surface and is supported. The area of the surface can be secured more stably. The large-diameter portion of the present aspect is formed by, for example, uniformly thickening the stent mounting portion when manufacturing the shaft, or by applying a synthetic resin material to the tip portion of the shaft, or by attaching a tubular member to the shaft. It can be formed by simple means, such as extrapolated to.

  A fifth aspect of the present invention is the stent delivery catheter according to any one of the first to third aspects, wherein the outer diameter of the large diameter portion is partially different.

  According to the stent delivery catheter having the structure according to this aspect, the outer diameter of the large diameter portion is partially different, and the degree of freedom can be expanded with respect to the structure and manufacturing of the large diameter portion. Specifically, for example, the large-diameter portion may have a shape extending spirally in the circumferential direction with respect to the shaft, and a plurality of ridges are provided at a predetermined distance in the axial direction or the circumferential direction. Such a shape or a structure in which a net-like convex portion is provided on the outer peripheral surface of the shaft may be used.

  According to a sixth aspect of the present invention, in the stent delivery catheter according to the fifth aspect, the large-diameter portion has a stent position in which the outer diameter dimension is larger than the other axial portion of the large-diameter portion. The defining portion is partially provided in the axial direction.

  According to the stent delivery catheter having the structure according to this aspect, the stent position defining portion is provided with the stent position defining portion whose outer diameter is further increased in the axial direction in the large diameter portion of the shaft. At this point, the stent is positioned and mounted on the shaft with a stronger holding force to prevent the stent from falling off the shaft. In addition, the diameter of the shaft does not have to be greatly reduced in order to obtain a strong holding force by avoiding the overlapping of struts when the diameter is reduced, and stable expansion of the stent is achieved. Is done.

  Furthermore, when the diameter of the stent extrapolated to the shaft and the balloon is reduced, the inner diameter of the stent can be smaller than the outer diameter of the stent position defining portion in a region where the stent has deviated from the stent position defining portion of the large diameter portion. According to this, since the stent is locked in the axial direction with the stent position defining portion and the stent is positioned in the axial direction with respect to the shaft, it is possible to further prevent the stent from dropping off from the shaft. .

  A seventh aspect of the present invention is the stent delivery catheter according to any one of the first to sixth aspects, wherein the shaft is provided with a guide wire lumen through which the guide wire is inserted.

  According to the stent delivery catheter structured according to the present embodiment, the catheter can be easily guided to the lesion along the guide wire. In particular, since the guide wire lumen is provided on the shaft, the complexity of the structure can be avoided. The stent delivery catheter according to the present invention may be a rapid exchange type catheter or an over-the-wire type catheter.

  According to the stent delivery catheter having a structure according to the present invention, the outer diameter of the balloon at the time of folding can be adjusted and set large because the large diameter portion is provided in the stent mounting portion of the shaft. Thereby, the non-uniform diameter reduction of the stent with which a balloon is mounted | worn can be avoided, and a stent can be mounted | worn stably.

1 is a front view showing the entirety of a stent delivery catheter as a first embodiment of the present invention. The front view which expands and shows the principal part of the stent delivery catheter shown by FIG. The longitudinal cross-sectional view in the principal part of the stent delivery catheter shown by FIG. The enlarged view in the IV-IV cross section of FIG. FIG. 3 is a diagram showing a specific example of a stent that can be employed in the present invention, and is a development view cut open at one place in the circumferential direction. The longitudinal cross-sectional view which shows the large diameter part of the shaft in the stent delivery catheter as the 2nd Embodiment of this invention. The longitudinal cross-sectional view of the principal part in the stent delivery catheter as the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, FIGS. 1 to 4 show a stent delivery catheter (hereinafter referred to as a catheter) 10 as a first embodiment of the present invention. A balloon 12 is attached to the distal end portion of the catheter 10, and a stent 14 is extrapolated to the balloon 12. The stent 10 is delivered and placed in the stenotic part of the lumen such as a blood vessel by the catheter 10 so that the stenotic part of the lumen is maintained in an expanded state. In the following description, the proximal end side refers to the right side in FIG. 1 where the user operates the catheter 10, and the distal end side is a view that is far from the user during use. Say the left side of 1. Moreover, an axial direction means the left-right direction in FIG.

  More specifically, the catheter 10 of this embodiment has a structure in which a connector 18 is provided on the proximal end side of the catheter body 16. This catheter body 16 is configured by connecting a distal shaft 20 on the distal end side and a proxy shaft 22 on the proximal end side in the axial direction.

  The proxy shaft 22 has a single tube structure extending in the axial direction, and is formed of a synthetic resin such as polyamide elastomer or a metal such as stainless steel. The proximal end of the proxy shaft 22 is connected to the connector 18, and the lumen of the proxy shaft 22 is communicated with the external space through the connector 18.

  On the other hand, the distal shaft 20 has a double tube structure of an inner shaft 24 and an outer shaft 26 as a shaft as a whole. The inner shaft 24 is configured to include an inner shaft main body 28, and the outer diameter of the inner shaft main body 28 is smaller than the inner diameter of the outer shaft 26. The proximal end of the inner shaft main body 28 is inserted into the outer shaft 26, and the distal end of the inner shaft main body 28 protrudes from the distal end of the outer shaft 26.

  Here, the outer shaft 26 has a tubular shape extending in the axial direction, and is formed of a synthetic resin such as polyamide elastomer. The outer diameter of the outer shaft 26 is substantially equal to that of the proximal shaft 22, and the proximal end of the outer shaft 26 and the distal end of the proximal shaft 22 are connected. Thereby, the lumen of the outer shaft 26 and the lumen of the proxy shaft 22 are communicated.

  The inner shaft main body 28 has a tubular shape extending in the axial direction as a whole, and is formed of a synthetic resin such as polyamide elastomer. A tip tip 30 is fixed to the distal end of the inner shaft main body 28. The tip 30 is cylindrical and has substantially the same outer diameter as the inner shaft body 28. On the other hand, the proximal end of the inner shaft main body 28 is bent and opened on the outer peripheral surface of the outer shaft 26. Thereby, the lumen of the inner shaft main body 28 is a lumen that opens to the distal end of the catheter 10 and an intermediate portion in the axial direction, and this lumen is a guide wire lumen through which a guide wire for guiding the catheter 10 is inserted. 32. That is, the catheter 10 of the present embodiment is a rapid exchange type catheter in which the guide wire lumen is shorter than the total length in the axial direction of the catheter.

  The balloon 12 is attached to the tip portion of the inner shaft 24 having such a structure. The balloon 12 can be expanded or contracted by introducing and discharging a fluid therein, and is a cylindrical or bag-shaped member formed of a thin synthetic resin, a rubber film, or the like. In addition, although the material of the balloon 12 is not limited at all, in this embodiment, the balloon 12 is formed of nylon resin, and the balloon 12 is applied to a pressure applied when expanding by supplying a fluid therein. It is a low compliant balloon with a small change in outer diameter. Further, in order to suppress the influence on the flexibility of the inner shaft 24, it is desirable that the balloon 12 be as thin as possible while ensuring the strength capable of expanding the stent 14 (to be described later) during expansion.

  The distal end of the balloon 12 is fixed to the distal end of the inner shaft body 28 and the outer peripheral surface of the tip chip 30 by adhesion or the like, while the proximal end of the balloon 12 is the outer periphery of the distal end of the outer shaft 26. It is fixed to the surface by adhesion or the like. Therefore, a space between the inner shaft main body 28 and the outer shaft 26 in the radial direction is communicated with the internal space of the balloon 12, and is communicated with the external space through the proxy shaft 22. Thus, fluid can be introduced and discharged from the outer space to the inner space of the balloon 12 through the space between the inner shaft main body 28 and the outer shaft 26 in the radial direction, and from the inner space of the balloon 12 to the outer space. The inner lumen is a supply / discharge lumen 33 that supplies and discharges fluid to / from the balloon 12.

  Further, substantially cylindrical markers 34 and 34 are extrapolated on the outer peripheral surface of the inner shaft main body 28 at both end portions in the axial direction of the balloon 12. These markers 34, 34 are made of a material such as platinum that is opaque to X-rays.

  As shown in FIG. 4, the balloon 12 in the initial state is in a wrapping state folded in the circumferential direction so as to overlap in the radial direction.

  A substantially cylindrical stent 14 extending in the axial direction as a whole is externally attached to the balloon 12. The shape of the stent is not limited as long as it has a skeletal structure extending in the circumferential direction while being folded back in the axial direction, but the stent 14 of the present embodiment is shown in a developed view in FIG. 5 as a specific example. As shown, one linear body 36 has a skeleton structure that spirally extends in the circumferential direction as a whole while reciprocating in the axial direction with a substantially constant amplitude. Particularly, it is preferable that the circumferential wave number in one turn, that is, the number of repeating units of the periodic structure in one turn of the linear body 36 is 10 to 12, which is larger than that of a general coronary stent. In the form of the stent 14, there are 12 waves. Moreover, although the material of a stent is not limited at all, in the stent 14 of this embodiment, it is formed with the cobalt chromium alloy. In the stent 14, as shown in FIG. 2, one linear body 36 constitutes a plurality of annular bodies 38, and the plurality of annular bodies 38 are arranged in parallel in the axial direction. It is set as the structure, and the annular bodies 38 and 38 which adjoin an axial direction may be connected and reinforced by the suitable location of the circumferential direction.

  By adopting a stent having a higher wave number than the general stent as described above, the diameter of the stent can be expanded further when the diameter is expanded. For example, a thicker lumen or a branched lumen can be accommodated. . Further, since the wave number is large, the surface area of the linear body 36 can be increased, and when used as a drug-eluting stent (DES), the amount of drug applied to the surface of the linear body 36 is increased. Can be made.

  In the initial state, the stent 14 is mechanically reduced in diameter and is externally attached to the balloon 12 as shown in FIG.

  Here, the attachment portion of the inner shaft 24 where the stent 14 is attached is provided with a large-diameter portion 42 whose outer diameter is larger than the proximal end side adjacent portion 40 of the attachment portion. In the present embodiment, the outer diameter dimension of the attachment portion of the stent 14 is larger than the proximal end side adjacent portion 40 of the attachment portion of the stent 14 by attaching the covering member 44 to the outer peripheral surface of the inner shaft main body 28. A large-diameter portion 42 having a large diameter is configured. In the present embodiment, the inner shaft 24 is configured by the inner shaft main body 28 and the covering member 44.

  The covering member 44 has a substantially tubular shape extending in the axial direction. In the present embodiment, the covering member 44 has an axial dimension that is substantially the same as or slightly larger than the axial dimension of the stent 14 and has a total axial length. And has a substantially constant outer diameter. In other words, in the present embodiment, the outer diameter of the large diameter portion 42 is substantially constant throughout. The stent 14 is mounted on the balloon 12 on the outer peripheral side of the covering member 44. The material of the covering member 44 is not limited in any way, but it is preferable to use a material having a hardness lower than that of the inner shaft main body 28. For example, a synthetic resin such as a polyamide elastomer, a polyester elastomer, or polyurethane is preferable. Can be adopted.

  Further, the method of attaching the covering member 44 to the inner shaft main body 28 is not limited in any way. For example, a synthetic resin material dissolved in a solvent is applied to the inner shaft main body 28 and dried, or has heat shrinkability. The tubular member may be closely attached to the inner shaft main body 28 by extrapolating the tubular member to the inner shaft main body 28 and applying heat. In particular, since the covering member 44 of the present embodiment has a substantially constant outer diameter throughout, there is no need for a special operation or the like for making the outer diameter different. Can be easily manufactured.

  Further, the radial width dimension α (see FIG. 4) of the covering member 44 is not particularly limited. For example, the outer diameter dimension φA (see FIG. 4) of the inner shaft main body 28 is 0.5 mm to 0.00 mm. When the outer diameter φB (see FIG. 4) of the balloon 12 when the diameter is reduced to 6 mm is set to 2 mm to 3 mm, it is preferably set within a range of 0.1 mm to 0.5 mm. When the outer diameter of the inner shaft main body, the balloon at the time of diameter reduction, or both are outside the above range, the radial width dimension of the covering member can be set as appropriate.

  As a method of using the stent delivery catheter 10 of the present embodiment, first, the stent 14 is arranged on the outer peripheral side of the balloon 12 in the lapping state, and the stent 14 is formed into the balloon 12 by reducing the diameter by mechanical processing or the like. Install extrapolated. Then, the catheter 10 is inserted into the lumen, and is externally inserted into a guide wire previously inserted into the narrowed portion of the lumen, that is, the guide wire is inserted into the guide wire lumen 32, so that the distal end portion of the catheter 10 is inserted. To reach the stenosis of the lumen. Thereafter, a fluid is supplied into the balloon 12 through the supply / discharge lumen 33 to expand the balloon 12 and the stent 14 extrapolated to the balloon 12. As a result, the stent 14 is pressed against the stenosis of the lumen to expand the stenosis. Then, the fluid in the balloon 12 is discharged through the supply / discharge lumen 33, the balloon 12 is deflated, and the catheter 10 is extracted from the lumen, whereby the stent 14 is indwelled in the narrowed portion of the lumen.

  In the stent delivery catheter 10 of this embodiment having such a structure, since a relatively high wave number is used as the delivered stent 14, the diameter of the stent 14 is reduced when the stent 14 is externally attached to the balloon 12. The inner diameter tends to increase. Here, in the catheter 10, since the large diameter part 42 is provided in the attachment part of the stent 14 in the inner shaft main body 28, the outer diameter of the balloon 12 in the wrapping state can be increased, and the wrapping state can be increased. It is possible to prevent the outer diameter of the balloon 12 from becoming too small compared to the inner diameter of the stent 14 when the diameter is reduced. As a result, it is possible to avoid the diameter of the stent 14 from being reduced non-uniformly, and since the stent 14 is extrapolated to the balloon 12 substantially uniformly, the diameter of the stent 14 is increased substantially uniformly even when the stent 14 is expanded. can do. Further, it is not necessary to increase the film thickness of the balloon 12 in order to increase the outer diameter dimension of the balloon 12, and the thin film balloon 12 can be employed. Therefore, flexibility at the distal end portion of the catheter 10 can be ensured.

  In particular, in the present embodiment, since the large-diameter portion 42 is configured by mounting the covering member 44 on the outer peripheral surface of the mounting portion of the stent 14 in the inner shaft main body 28, the large-diameter portion 42 is easily formed. Can be formed.

  Furthermore, by making the hardness of the covering member 44 smaller than the hardness of the inner shaft main body 28, the flexibility at the distal end portion of the catheter 10 can be ensured more reliably.

  In this embodiment, since the guide wire lumen 32 is provided in the inner shaft main body 28, it is not necessary to provide a guide wire lumen separately, and the structure of the catheter 10 can be simplified.

  Furthermore, the suitable aspect of this invention is a stent delivery catheter which concerns on this invention for coronary arteries, and the wave number in 1 round of a stent shall be 10-12. In the present embodiment, the mounted stent 14 has a relatively large number of waves per turn (the number of repeating units of the periodic structure in one turn) compared to a general coronary stent. Therefore, when the width of the strut is secured and an attempt is made to reduce the diameter of the stent 14 when the diameter of the stent 14 is reduced, adjacent struts are likely to overlap each other in the circumferential direction and become a distorted reduced diameter shape. Here, in the present invention, by providing the large-diameter portion 42 at the mounting portion of the stent 14 in the inner shaft 24, non-uniform shrinkage deformation due to excessive shrinkage of the stent 14 can be avoided. By adopting such a stent 14, the ratio of the diameter dimension at the time of diameter expansion to the diameter dimension at the time of diameter reduction of the stent 14 can be set large, while ensuring the delivery performance into the lumen, In addition to being able to handle thick lumens and branched lumens, when used as a drug-eluting stent (DES), the surface area of the stent strut increases, so the amount of drug carried is increased. Is also possible.

  Next, FIG. 6 shows a large-diameter portion 48 of the inner shaft 46 as a shaft in the stent delivery catheter as the second embodiment of the present invention. In the stent delivery catheter of the present embodiment, members other than the inner shaft 46 are the same as those in the first embodiment, and are not shown. Further, in the following description, the same reference numerals as those of the first embodiment are given to the members or portions substantially the same as those of the first embodiment in the drawings, and detailed description thereof is omitted.

  In the first embodiment, the covering member 44 has a tube shape and the outer diameter dimension is substantially constant over the entire length in the axial direction. However, in this embodiment, the inner shaft main body 28 as a shaft main body is used. A large-diameter portion 48 is configured by mounting a covering member 50 that extends spirally in the circumferential direction with respect to the outer peripheral surface of the inner shaft main body 28 at the mounting portion of the stent 14 in FIG. Thereby, the outer diameter dimension in the large diameter part 48 is made larger than at least the proximal end side adjacent part 40. That is, in the present embodiment, the outer diameter of the large diameter portion 48 is partially different in the axial direction.

  Also in the stent delivery catheter employing the inner shaft 46 having such a structure, the same effect as that of the stent delivery catheter 10 described in the first embodiment can be exhibited.

  The covering member 50 of the present embodiment has a rectangular cross section. For example, a synthetic resin piece that extends in a straight line is wound around the outer peripheral surface of the inner shaft main body 28 and fixed by adhesion or welding. A diameter 48 may be configured. However, the covering member is not limited to a rectangular cross section, and various cross sectional shapes such as a circular cross section, a semicircular cross section, and a polygonal cross section can be adopted. The large-diameter portion is not limited to the aspect in which the covering member is provided spirally in the circumferential direction on the outer peripheral surface of the inner shaft body, and a plurality of annular ridges are provided in the axial direction or the ridges extending in the axial direction are surrounded. It may be partially provided in the direction. In particular, in the structure in which a plurality of annular ridges are provided in the axial direction, by providing the ridges at both axial ends of the mounting portion of the stent 14, the stent 14 is supported at both axial ends, and the inner shaft 46 and A stable attachment to the balloon 12 can be realized.

  FIG. 7 shows a distal portion of a stent delivery catheter 60 as a third embodiment of the present invention. The stent delivery catheter 60 of this embodiment includes an inner shaft 62 as a shaft.

  More specifically, the inner shaft 62 has a structure in which the tip 30, the covering member 44, and the diameter expanding member 64 constituting the stent position defining portion are attached to the inner shaft main body 28 as the shaft main body. Has been.

  The diameter-expanding member 64 is an annular or cylindrical member formed of a flexible synthetic resin material similarly to the covering member 44, and in this embodiment, at the distal end and the proximal end of the covering member 44, respectively. It is attached in an extrapolated state and is fixed to the covering member 44 by means such as adhesion or welding. Thereby, the large diameter portion 66 of the present embodiment is formed by the covering member 44 and the diameter expanding member 64, and the outer diameter dimension of the large diameter portion 66 is partially different in the axial direction. At both ends in the axial direction where 64 is disposed, stent position defining portions having a diameter larger than that in the axially intermediate portion away from the diameter-expanding member 64 are provided.

  The balloon 12 is fixed to the inner shaft main body 28 and the tip 30 at a position distal to the large diameter portion 66, and is fixed to the outer shaft 26 at a position proximal to the large diameter portion 66. An intermediate portion in the axial direction is overlaid on the outer peripheral surface of the large diameter portion 66.

  In addition, the balloon 12 has an outer diameter that is increased over the entire length of the portion that is overlapped with the large-diameter portion 66, and a portion that is overlapped with both end portions in the axial direction of the large-diameter portion 66 including the diameter-expanding member 64. The diameter is larger. Thus, there is a step between the overlapping portion of the large diameter portion 66 on both ends in the axial direction of the balloon 12 and the overlapping portion of the large diameter portion 66 on the intermediate portion in the axial direction outside the diameter expanding member 64. 68 is formed.

  A stent 14 is attached to the balloon 12 in an extrapolated state. That is, the stent 14 is fitted to the outer peripheral surface of the balloon 12 by being extrapolated to a portion of the balloon 12 overlapped with the large-diameter portion 66 and deformed in a reduced diameter. Thus, also in this embodiment, the mounting portion of the stent 14 on the inner shaft 62 is the large-diameter portion 66 as in the above-described embodiment.

  Further, both end portions in the axial direction of the stent 14 are overlapped with the diameter-expanding member 64 of the large-diameter portion 66 via the balloon 12, and both end portions in the axial direction have a larger diameter than the intermediate portion from which the diameter-expanding member 64 is removed. Has been. As a result, both axial end portions of the stent 14 are fitted to the inner shaft 62 with a greater pressure than the intermediate portion.

  Furthermore, there is a step 70 between the portion of the stent 14 where the large-diameter portion 66 is attached to both ends in the axial direction and the portion of the large-diameter portion 66 where the large-diameter portion 66 is removed from the axially intermediate portion. Is formed. The step 14 of the balloon 12 and the step 70 of the stent 14 are locked in the axial direction, whereby the stent 14 is positioned in the axial direction with respect to the balloon 12.

  According to such a stent delivery catheter 60, the large diameter portion 66 provided on the inner shaft 62 can be adjusted as appropriate so that the outer diameter of the balloon 12 in the lapping state does not become too small. Therefore, for example, even when the balloon 12 is thin and the wave number of the stent 14 is large, the stent 14 fitted on the balloon 12 is prevented from becoming too small in diameter, and the linear body 36 is reduced when the diameter of the stent 14 is reduced. Problems such as overlap can be avoided.

  In addition, according to the present embodiment, the outer diameter dimension of the both ends in the axial direction of the large-diameter portion 66 is made larger by including the diameter-expanding member 64, and the stent position defining portion is provided at both axial ends of the large-diameter portion 66. The both ends of the stent 14 in the axial direction are attached to the balloon 12 and the inner shaft 62 with a larger force. As a result, the stent 14 can be firmly positioned by the balloon 12 and the inner shaft 62 in the contracted state, and the stent 14 before expansion can be prevented from being detached from the inner shaft 62, and at an appropriate position on the balloon 12. Retained. In particular, since the diameter-expanding members 64 are disposed at both axial ends of the large-diameter portion 66, the stent 14 is strongly supported at both axial ends, and the stent 14 is attached to the balloon 12 and the inner shaft 62. Is maintained more stably.

  Moreover, the stent 14 is positioned in the axial direction with respect to the balloon 12 and the inner shaft 62 also by the step 68 of the balloon 12 and the step 70 of the stent 14 being locked in the axial direction. As a result, separation of the stent 14 from the inner shaft 62 and displacement of the stent 14 with respect to the balloon 12 are avoided, and the stent 14 before expansion is held in an appropriate mounting state.

  The stent position defining portion is not necessarily limited to those provided at both axial ends of the large-diameter portion 66. For example, the stent position defining portion is provided at one end in the axial direction and not provided at the other end. Alternatively, in addition to or instead of the axial end portion, one or a plurality of intermediate portions in the axial direction may be provided. The stent position defining portion may be formed by fixing another member such as the diameter-expanding member 64 to the inner shaft 62. For example, the covering member 44 may be partially thickened to form the covering member. 44 may be provided integrally with the inner shaft 44 or may be provided by partially increasing the outer diameter of the inner shaft main body 28 in the axial direction.

  Further, the step 68 of the balloon 12 and the step 70 of the stent 14 are not essential. For example, the stent 14 may be reduced in diameter to a substantially constant diameter along the entire axial length including the portion where the stent position defining portion (the diameter-expanding member 64) is removed. Is not formed. Further, when the entire stent 14 is reduced in diameter to a substantially constant diameter, both end portions in the axial direction of the balloon 12 are abutted and supported by the stent position defining portion, while the balloon 12 which is out of the stent position defining portion. The intermediate portion of the balloon 12 may be separated from the covering member 44 toward the outer periphery, and the step 68 of the balloon 12 may not be formed.

  The embodiment of the present invention has been described in detail above, but the present invention is not limited to the above-described solution and the specific description in the embodiment, and is within the scope of the present invention. The present invention can be implemented in a mode with appropriate modifications and improvements.

  For example, in the above-described embodiment, the large-diameter portions 42 and 48 are configured by mounting the separate covering members 44 and 50 on the outer peripheral surface of the inner shaft main body 28. It may be formed integrally with the main body. That is, when manufacturing the inner shaft main body, the large diameter portion may be formed by manufacturing the outer diameter of the mounting portion of the stent 14 larger than the proximal end side adjacent portion. At this time, if the inner diameter of the stent 14 is increased and the inner diameter is increased, the thickness of the inner shaft main body is not increased, so that the flexibility at the distal end portion of the catheter is large. A diameter part can be formed.

  In the above embodiment, the inner shaft main body 28 has a tube shape, and the guide wire lumen 32 is formed by the lumen of the inner shaft main body 28. However, the guide wire lumen is not essential, and the inner shaft The body may be a solid shaft. Further, the distal shaft 20 has a double-pipe structure of an inner shaft 24 and an outer shaft 26. For example, the distal shaft 20 has a double-lumen structure having a guide wire lumen and a supply / discharge lumen inside a single shaft. May be. However, since the guide wire lumen is not essential, the distal shaft may have a single tube structure having only a supply / discharge lumen.

  Furthermore, in the above-described embodiment, the guide wire lumen 32 is a rapid exchange type catheter that is shorter than the entire length of the catheter 10. However, the guide wire lumen is an over-the-wire type catheter that opens at the proximal end of the connector 18. It may be said.

  Furthermore, the stent employed in the present invention is not limited to a stent in which one linear body as described in the above embodiment extends spirally in the circumferential direction. That is, one linear body is folded in the axial direction and forms one annular body while extending in the circumferential direction, and a plurality of the annular bodies are arranged side by side on the same central axis. The stent may be connected in an axial direction at an appropriate position on the circumference.

  In the above-described embodiment, a coronary stent having a wave number of 10 to 12 is exemplified, but the present invention is not limited to this. For example, a stent for peripheral blood vessels may be employed as the stent, and in such a case, it is preferable that the wave number is 18-24.

10, 60: Stent delivery catheter, 12: balloon, 14: stent, 24, 46, 62: inner shaft (shaft), 28: inner shaft body (shaft body), 32: guide wire lumen, 40: proximal end side Adjacent portion, 42, 48, 66: Large diameter portion, 44, 50: Cover member, 64: Expanded diameter member (stent position defining portion)

Claims (7)

A stent delivery catheter in which a balloon is attached to a distal end portion of a shaft, a stent is attached to the balloon, and the stent has a skeletal structure extending in the circumferential direction while being folded back in the axial direction.
The stent delivery catheter according to claim 1, wherein a portion of the shaft on which the stent is mounted is provided with a large-diameter portion having an outer diameter larger than that of a portion adjacent to the proximal end of the mounting portion.   The outer diameter of the large-diameter portion is made larger than the outer diameter of the adjacent portion on the proximal end side of the mounting portion of the shaft body by mounting the covering member on the outer peripheral surface of the shaft body. The stent delivery catheter according to claim 1.   The stent delivery catheter according to claim 2, wherein the hardness of the covering member is smaller than the hardness of the shaft body.   The stent delivery catheter according to any one of claims 1 to 3, wherein an outer diameter of the large diameter portion is constant throughout.   The stent delivery catheter according to any one of claims 1 to 3, wherein the outer diameter of the large diameter portion is partially different.   The stent delivery according to claim 5, wherein the large-diameter portion is partially provided with a stent position defining portion having a larger outer diameter than the other axial portion of the large-diameter portion in the axial direction. catheter.   The stent delivery catheter according to any one of claims 1 to 6, wherein a guide wire lumen through which a guide wire is inserted is provided on the shaft.

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