JP2002355315A - Stent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent flexible in its axial direction even before and after expanded. SOLUTION: This stent has an expansible member (11) comprising corrugated elements (111) arranged so as to spirally surround the longitudinal axis of the stent and a plurality of corrugated connection members (12) for mutually connecting the ridges and/or troughs of the corrugated elements (111) of the expansible member (11). The corrugated elements (111) develop the ridges and troughs of the corrugations thereof cyclically so as to cross the peripheral direction of the stent. Each of the corrugated connection members (12) has a plurality of corrugations having amplitude larger than that of other corrugations in the gaps between the corrugated elements adjacent to each other in the axial direction of the stent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stent for indwelling a living body used for improving a stenosis or obstruction formed in a lumen of a blood vessel, a bile duct, a trachea, an esophagus, a urethra, and other organs. And more particularly to balloon-expandable stents.

[0002]

2. Description of the Related Art A stent is used to expand a stenosis or occlusion site and to secure the lumen to treat various diseases caused by stenosis or occlusion of a blood vessel or other body lumen. It is a generally tubular medical device to be placed at the site.

[0003] Among these stents, a balloon-expandable stent does not have a self-expanding function unlike a self-expandable stent, and after being inserted into a target site, expands the balloon in the stent and expands the stent by the expanding force of the balloon. (Plastic deformation) so as to be brought into close contact with the inner surface of the target lumen portion and fixed.

[0004]

Generally, basic functions that a stent should have include a delivery performance and a restenosis prevention function. The delivery performance is a function of the stent that can be transported to a target intraluminal site. If the stent cannot be delivered to the target site, the stent cannot be naturally placed, so it is a very basic function. In particular, regarding the balloon-expandable stent, factors involved in this delivery performance include the stent diameter when mounted on the balloon catheter, the adhesion between the balloon and the stent when mounted on the balloon catheter, and the like, In particular, the flexibility of the stent mounted on the balloon catheter is important.

The flexibility when mounted on a balloon catheter is a physical property necessary for advancing to follow a guide wire which is indwelled even in a bent or meandering blood vessel. A stent with poor axial flexibility
The patient may not be able to follow the guidewire and deliver it to the lesion site. This is especially true for long stents. Also, when bending and passing through more calcified lesions, the stent may be caught by the hardened calcified intima and may not progress further. In particular, when the stent bends, a portion of the strut protrudes outward, which abuts a hard lesion and does not advance. Also, a problem that often occurs in the clinic, since the stent does not pass through the lesion, when the stent is pulled back into the guiding catheter, a part of the stent is caught at the tip of the guiding catheter and cannot be collected.
The stent may fall off from the balloon catheter.

On the other hand, the restenosis prevention function is a function that can prevent restenosis in a portion where a stent is placed. The mechanism of this restenosis has not been completely elucidated yet, and because of the complex and diverse pathology in clinical studies, it is difficult to conduct a restenosis comparison test using a stent. Whether the stent contributes to a reduction in the rate of restenosis is not fully understood. However, stents with poor axial flexibility are said to be prone to restenosis at the edges of the stent, and this is thought to be due to the fact that the edges are stressed due to the stiffness and stimulate blood vessels. I have. Thus, it is considered that the stent should be flexible after the stent is expanded and deployed. However, a stent having no free portion is generally said to have a high restenosis rate at the edge of the stent because it is hard in the axial direction.

Accordingly, it is an object of the present invention to provide a stent that is axially flexible before and after expansion.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention has a first outer diameter which is formed in a tubular shape as a whole and can be inserted into a living body lumen, and has a radially outer portion inside. A stent that is expandable to a second outer diameter greater than the first outer diameter when an expanding force in a direction is applied to the stent, the wave arranged to surround the longitudinal axis of the stent in a spiral manner. An expanding member comprising a mold element; and a plurality of corrugated connecting members for connecting the peaks and / or valleys of the corrugated element of the expanding member, wherein the corrugated element is provided on the periphery of the stent. The peaks and valleys of the wave appear periodically so as to intersect in the direction, and each wave-shaped connecting member has a plurality of waves, and in the gap between the wave-shaped elements adjacent in the axial direction of the stent, other waves. Expandable, characterized by having a wave of greater amplitude than the To provide cement.

[0009] In the present invention, it is preferable that ridges and valleys and valleys and valleys of substantially all corrugated elements adjacent in the longitudinal axis direction of the stent are connected by a corrugated connecting member.

[0010] In the present invention, it is preferable that corrugated elements adjacent in the longitudinal axis direction of the stent are arranged so that a phase difference does not substantially occur in the waves.

In the present invention, preferably, the width of each corrugated connecting member is equal to or less than 1/2 of the width of the corrugated element, and particularly, the width of each corrugated connecting member is 0.03 mm to 0.08 mm.
In the range.

Further, in the present invention, preferably, the largest wave in each corrugated connecting member is larger than the width of the peak or valley of the corrugated element when the stent has the first outer diameter.

In the present invention, the total extension of the corrugated connecting member is at least 1.3 times the linear distance between the peaks or the valleys of the corrugated elements adjacent in the longitudinal direction of the stent. Preferably, there is.

Further, in the present invention, the width of the gap between corrugated elements adjacent to each other in the longitudinal axis direction of the stent is 0.4 to 0.4.
It is preferably 1.7 mm.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

[0016] The stent of the present invention is formed in a tubular shape as a whole, has a first outer diameter that can be inserted into a living body lumen, and has a first outer diameter when a radially outward expanding force is applied inside. It is expandable to a second outer diameter larger than the first outer diameter.

FIG. 1 shows a state in which the stent of the present invention is mounted on a balloon catheter, that is, has a first outer diameter small enough to be inserted into a living body lumen (unexpanded state). It is an expansion development view of the stent concerning one embodiment. FIG. 2 is an enlarged view showing a part of the stent shown in FIG.

The stent 10 shown in FIGS. 1 and 2 has an expansion member 11 composed of a corrugated element 111 and a peak of corrugated elements adjacent to each other in the longitudinal direction of the stent (indicated by X in FIG. 1). And / or a corrugated connecting member 12 for connecting valleys to each other.

Each of the expanding members 11 expands to a second outer diameter larger than the first outer diameter when a force spreading radially outward in the inside thereof is applied, and the force is removed. Sometimes, it retains its expanded shape and is comprised of corrugated elements 111 arranged spirally around the longitudinal axis of the stent.

The corrugated element 111 is formed in a spiral shape such that peaks and valleys of the wave periodically appear in a direction intersecting the circumferential direction of the expanding member 11 at a predetermined angle.

The corrugated elements 111 are arranged such that waves adjacent to each other in the longitudinal axis direction of the stent do not substantially cause a phase difference and are parallel to each other at a predetermined interval d (see FIG. 2) in the longitudinal axis direction of the stent 10. Preferably they are arranged. That is, the expansion member 11 is preferably arranged such that peaks and valleys and valleys and valleys in waves adjacent to each other in the longitudinal axis direction of the stent are aligned in parallel with the axial direction of the stent 10 (peaks and valleys of waves). Is defined as a peak on one side of the corrugated element 111 and a valley on the other side of the corrugated element 111. For convenience, the left side of FIG. The bent portion is called a peak (indicated by M in FIG. 2), and the right bent portion is called a valley (indicated by V in FIG. 2.) In the embodiment shown in FIG. Spiral rotation.

Although there is no particular limitation on the waveform of the corrugated element 111 constituting the expansion member 11, it is preferably substantially U-shaped as shown in FIGS. More specifically, this U-shaped corrugated element 111, referring to FIG. 2, connects a substantially straight long segment 111a, a substantially straight short segment 111b, and connects these straight segments 111a and 111b. Curved segment 1
11c, adjacent straight long / short segments 111a and 111b are respectively staggered at their ends by one curved segment 111c.
Connected by

As shown in FIG. 2, the wave-shaped connecting member 12 includes a wave-shaped mountain connecting element 121 for connecting the waves adjacent to each other in the axial direction of the stent of the wave-shaped element 111 of the expanding member 11. Wave-shaped valley connecting element 12 connecting valleys
2 is included. In the case of the present stent, the mountain connection element 121
The mountain M on the left is connected to the mountain M on the right. The mountain connection element 121 has a plurality (eg, four) small waves 121b in the gap between the adjacent linear long / short segments 111a and 111b, and the wave connection elements 121 between the adjacent wave-shaped elements in the longitudinal direction of the stent. Has a wave 121c having a larger amplitude than the other waves 121b. Having a wave 121c with a larger amplitude than the other waves in the gap between adjacent wave elements 111 increases the flexibility of the stent 10. In the case of the present stent, the small wave 121b is connected to a straight member 121a directly connected to the peak. Here, the wave shape of the mountain connection element may be V-shaped, but is preferably an S-shape in which the directionality when bent is difficult. It is preferable that all the mountain connection elements 121 have the same shape. In addition,
In FIG. 1 and FIG. 2, the mountain connecting element 121 has four small waves between adjacent linear long / short segments 111 a and 111 b, and between the wave-shaped elements adjacent in the longitudinal direction of the stent. But with one large wave 121c, but is not limited to this, the mountain connection element has a plurality of waves, and between the corrugated elements adjacent in the longitudinal direction of the stent. It is sufficient that the gap has a wave having a larger amplitude than the other waves.

The corrugated valley connecting element 122 connects the left valley V to the right valley V. The valley connection element 122 is similar to the ridge connection element 121 in that the adjacent linear long / short segments 1
In the gap between 11a and 111b, there are a plurality of (eg four) small waves 122b, and between adjacent expansion members 11 between the longitudinally adjacent corrugated elements of the stent, another wave is present. The wave 122c has a larger amplitude than the wave 122c. By having a wave 122c with a larger amplitude than the other waves in the gap between adjacent expansion members 11, the stent 1
0 increases flexibility. The large wave 122c preferably has a wave height larger than the width of the gap between the adjacent linear segments 111a. The wave shape of the valley connection element 122 may be V-shaped, but it is difficult to provide a direction when bent.
A letter shape is preferred. Also, all valley connecting elements 122
Are preferably the same shape as shown in FIG. 1 and 2, the valley connecting element 122 is
Although shown as having four small waves 122b between adjacent linear long / short segments 111a and 111b, and one large wave 122c between adjacent corrugated elements in the longitudinal direction of the stent. Without limitation, the valley connecting element 122 has a plurality of waves, and a wave having a greater amplitude than the other waves in the gap between the corrugated elements adjacent in the longitudinal direction of the stent. Should just have. In a particularly preferred embodiment of the invention, the ridge connection element 121 and the valley connection element 122 are all of the same shape and differ only in orientation, as shown in FIG. Also, peaks and peaks and valleys and valleys of corrugated elements adjacent in the longitudinal axis direction of the stent are:
It is preferable that all are connected by the connecting member 12.

In the present invention, from the viewpoint of further increasing the flexibility before and after the expansion, the large wave of the wave-shaped connecting member (the wave existing in the gap between the adjacent expansion members 12) has a wave height H (FIG. 2).
However, the width w of the peak M or the valley V of the corrugated element 111 constituting the expansion member 11 is preferably larger. The width w of the peak M or the valley V is the distance between two points P1 and P2 where one curved segment connects to two linear long / short segments 111a in a state where the stent is deployed.

Since the expanding member 11 is required to be deformed when expanded and to maintain the deformed state and exhibit a counterforce sufficient to oppose the force when the blood vessel contracts.
It is preferable to have a certain width or thickness or more. On the other hand, the connecting member 12 may have a considerably small width as long as it only has to play a role of keeping the expansion members 11 at a certain distance without separating from each other. However, if the connecting member 12 is to have a function of expanding and holding the blood vessel, the width and the thickness of the expanding member are required. It becomes a poor stent.

However, it is an object of the present invention to provide a stent that is axially flexible before and after expansion. As a result of various studies on such flexibility, the present inventors have found that the connecting member 12 (the mountain connecting element 1)
By making the width of the valley connecting element 122 and the valley connecting element 122) 以下 or less of the width of the corrugated element 111 constituting the expanding member 11, the flexibility is further increased, and the distance between the corrugated elements 111 is further increased. Was maintained constant, and it was found that the function of the stent could be fully exhibited. Specifically, it was found that the width of the connecting member 12 was preferably from 0.03 mm to 0.08 mm, and more preferably from 0.04 mm to 0.06 mm.

If the gap d between the corrugated elements 111 is too wide, the flexibility of the stent 10 increases, but the number of the expansion members 11 having the function of expanding and holding per unit length decreases. The expansion holding force is relatively low. On the other hand,
If the gap d between the expansion members 11 is too narrow, the number of expansion members 11 per unit length increases, so that the expansion holding force increases relatively, but the flexibility becomes relatively poor. Therefore, as a result of studying to appropriately balance the conflicting demands of expansion retention and flexibility, the width of the gap d is preferably from 0.4 mm to 1.7 mm, and more preferably from 0.6 mm to 1.2 mm. It turned out to be more preferable.

Incidentally, as shown in FIG.
Have at their ends a second corrugated element 13 and a third corrugated element 1
4 These second and third corrugated elements 13, 1
Reference numeral 4 designates a configuration in which, in a state where the corrugated elements 111 are arranged in a spiral shape, both ends thereof are flush with each other in a direction orthogonal to the longitudinal axis of the stent and the corrugated tips located at both ends. The second corrugated element 13 is composed of two waves, and is directly connected to the crest of the wave at one end, and the crest and the crest and valley of the spiral corrugated element adjacent thereto are corrugated connecting members 131. And 132 respectively. The third corrugated element 14 is composed of two waves, and is directly connected to the crest of the wave at one end, and the crest and the crest and valley of the spiral corrugated element adjacent thereto are corrugated. They are connected by members 141 and 142, respectively. Each connecting member 131, 132, 141, 1
Reference numeral 42 does not have a large wave as in the connecting member 12 connecting the spiral corrugated elements 111, but does not cause any particular problem since little flexibility is required in this part.

FIG. 3 is an expanded view of the stent 10 shown in FIG. 1 expanded to have the second outer diameter.
The corrugated element 111 that constitutes the expansion member 11 is deformed from the U-shape at the time of non-expansion shown in FIG. 1 to the V-shape, and the diameter of the stent 10 is increased accordingly. As long as the connecting member 12 expands the stent in a straight blood vessel that is not curved, its shape and length basically do not change. That is, by expanding the stent, the axial length of the expanding member 11 changes, but the adjacent peaks or valleys connected by the connecting member 12 change by the same length in the same direction. The length of 12 will not change. On the other hand, if the waves of the wave-shaped element 111 of the expansion member 11 are 180 degrees out of phase, that is, if the peaks and valleys of the wave of the wave-shaped element 111 are connected, the expansion member 11 And the connecting member 12 also extends. In the stent according to the present invention, the expansion members 11 are arranged in the axial direction so that there is no phase difference between the waves of the corrugated elements 111. Therefore, even when the stent is extremely expanded, the entire length thereof changes. An advantage of being difficult (substantially unchanged) is obtained. If the entire length of the stent is shortened by expansion, the entire stenosis of the target blood vessel cannot be expanded, or X
In some cases, a deviation may occur between an arrangement position assumed under the radiography and an actual arrangement state of the stent, and an effective stenosis may not be improved.

When the connecting member 12 is corrugated, not only the flexibility of the stent is increased as described above, but also the advantage that the treatment of the side branch can be easily performed is obtained.
The advantage is particularly remarkable in a stent to be placed in a coronary artery. The coronary artery has various side branches (refer to blood vessels in which a blood vessel smaller than the main vessel branches off from the main vessel) in a main thick blood vessel (hereinafter, referred to as a main vessel). If the stenosis is at the bifurcation between the main vessel and the side branch, the stent may be deployed including the bifurcation. In this case, as a result of placing the stent, the degree of stenosis of the side branch may be further increased or may be blocked. In many cases, clinical symptoms and myocardial infarction do not occur because the side branch is a thin blood vessel, but sometimes it presents with chest pain or infarct symptoms, and sometimes requires some treatment.

In that case, the gap 21 of the stent shown in FIG.
A guide wire is inserted into the side branch through the catheter, and a balloon catheter is delivered to the stenosis along the guide wire to expand and treat. In most cases, the stenosis is at the entrance of the side branch, so the walls of the stent will also expand. Further, in order to sufficiently exert the effect of expansion, it is necessary to expand the balloon with a balloon as close as possible to the blood vessel diameter of the side branch. When the balloon is expanded, the linear short segment 111b of the corrugated element 111 defining the gap 21 of the stent, the peak connecting element 121 and the valley connecting element 122 adjacent in the circumferential direction, and the short segment 111b of the corrugated element 111 and the axial direction The short segment 111b of the corrugated element 111 adjacent to is deformed into a substantially circular shape as the balloon expands. As described above, since it is preferable to expand the balloon with a balloon as large as possible, the length of the circumference is preferably longer. In the present invention, since the connecting member 12 is corrugated, the peripheral length of the gap 21 is longer than when the connecting member 12 is straight, and there is an advantage that a large balloon can be used. From such a viewpoint, it is particularly preferable that the total extension of each corrugated connection member 12 is at least 1.3 times the linear distance between the peaks or the valleys of the adjacent expansion members 11. The linear long segment 111a of the corrugated element 111, the peak connecting element 121 and the valley connecting element 122 adjacent in the circumferential direction, and the length of the corrugated element 111 axially adjacent to the long segment 111a of the corrugated element 111. The segment 111a is
Although a larger gap 22 is formed, it is not known whether the guide wire actually passes through the gap 21 or the gap 22. Therefore, a small balloon that can be inserted into the smaller gap 21 is used. It is more convenient.

The material for forming the stent 10 is preferably a material having biocompatibility, for example, stainless steel,
Examples include tantalum or a tantalum alloy, platinum or a platinum alloy, gold or a gold alloy, and a cobalt-based alloy. In addition, noble metal plating (gold, platinum) may be applied after forming the stent shape. As stainless steel, SUS316L, which has the highest corrosion resistance, is preferable. Furthermore, after creating the final shape of the stent 10,
Annealing is preferred. By performing the annealing, the flexibility and plasticity of the entire stent are improved, and the indwellability in the bent blood vessel is improved. Compared to the case without annealing, the force for restoring the pre-expansion shape after expanding the stent, especially the force for returning to the linear shape developed when expanded at the bent vascular site, The physical stimulus applied to the bent blood vessel inner wall is reduced, and the cause of restenosis can be reduced. Annealing is performed so that no oxide film is formed on the stent surface.
Under an inert gas atmosphere (for example, argon gas), 9
After heating to 00 to 1200 ° C., it is preferable to carry out by cooling slowly.

The stent 10 of the present invention can be preferably manufactured by using a method of hollowing out a portion of a stent from a metal pipe. Various methods can be adopted as the method of hollowing out the stent from the pipe. For example, there are an etching method using masking and chemicals called photo fabrication, an electric discharge machining method using a mold, and a mechanical cutting method.

The simplest method with a high processing accuracy is a laser processing method. As a laser processing machine,
A NEC YAG laser (trade name SL116E) can be used. Set the metal pipe on a jig with a rotating motor with a chuck mechanism so that the shaft does not move,
This is set on an XY table that can be numerically controlled. Then, the XY table and the rotary motor are connected to the personal computer, and the output of the personal computer is set so as to be input to the numerical controller and the rotary motor of the XY table. Drawing software is stored in the personal computer, into which a development drawing of the stent having the composition shown in FIG. 1 is input.
The XY table and the rotary motor are driven based on the drawing data output from the personal computer. By irradiating it with a laser, a stent structure having a shape as shown in FIG. 1 is created. Not limited to such a system, a so-called laser marker (galvanometer system) driven by a laser processing machine may be used.

Here, as a typical stent placement procedure using a balloon-expandable stent, a procedure for placing a coronary stent will be briefly described. First, a blood vessel is secured to introduce various catheters into the blood vessel. Suitable blood vessels (mainly femoral, elbow, and radial arteries)
Place the sheath in the container. The sheath is a device provided with a valve at the end of a thin plastic tube that prevents blood from leaking and that allows catheters to be inserted and withdrawn. A catheter called a guiding catheter is inserted through the sheath, and the tip is fixed to the right or left coronary artery ostium. Thereby, a passage from outside the body to the coronary artery is formed.

Next, a thin guide wire having a diameter of, for example, about 0.36 mm (0.014 inch) is inserted into the guiding catheter, passed through a stenotic portion of the coronary artery, and then placed along the guide wire at the distal end. A balloon catheter equipped with a balloon is inserted, and the balloon is expanded at the stenosis to expand the stenosis, and then the balloon catheter is removed.
Thereafter, a contrast agent is injected from the guiding catheter, and the degree of expansion of the stenosis is confirmed. If the stenosis has been sufficiently expanded and there is no problem, the procedure is completed.If the expansion is insufficient or the intima is detached, perform the operation to place the stent next. I do.

That is, the stent is mounted on a balloon (in a folded state) of a balloon catheter,
The balloon catheter is advanced to the stenosis along the guide wire in the same manner as described above, and X
The position of the balloon catheter is confirmed by positioning the distal end of the balloon catheter in the stenosis under fluoroscopy. Thereafter, a contrast agent is injected into the balloon at a high pressure, and the balloon is expanded by the force. By expanding the balloon, the stent is plastically deformed so as to expand in a radial direction, and expands (expands) as shown in FIG. 3, thereby expanding the stenosis. Next, the balloon is deflated by removing the pressure. Since the stent has an expansion holding force (shape holding force) due to plastic deformation, it remains at that position without shrinking, keeps the blood vessel expanded, and improves blood flow obstruction.
In this case, in the stent of the present invention, since the expansion member is formed of a corrugated element arranged in a spiral shape, not only can the expanded state be maintained with a substantially uniform expansion force on the blood vessel, but also in a curved stenosis, It can easily bend along its curvature.

[0039]

EXAMPLES The present invention will be further described below with reference to specific examples.

A long pipe of stainless steel (SUS316L) having a diameter of 1.4 mm and a wall thickness of 0.10 mm having a length of 10 mm
It was cut to 0 mm, and a desired stent was manufactured from the stainless steel pipe piece by a laser processing method. As a laser processing machine, NEC's YAG laser (trade name S
L116E) was used. The stainless steel pipe piece was set on a jig with a rotary motor equipped with a chuck mechanism so that the shaft did not move, and this was set on an XY table capable of numerical control. Then, the XY table and the rotating motor were connected to a personal computer, and the output of the personal computer was set so as to be input to the numerical controller and the rotating motor of the XY table. Drawing software is stored in the personal computer, into which a development drawing of the stent having the composition shown in FIG. 1 was input. Thus, based on the drawing data output from the personal computer, the XY table and the rotating motor are driven, and the laser beam is irradiated on the stainless steel pipe piece that moves with the XY table, so that the stent structure having the shape shown in FIG. Created things. The laser processing conditions were a current value of 25 A, an output of 1.5 W, and a driving speed of 10 mm / min.

Thus, a stent having the shape shown in FIG. 1 was produced. The produced stent has a total length of 15 m.
m, the outer diameter is 1.4 mm, the width of the corrugated element constituting the expansion member is 0.11 mm, and the width of each connecting member is 0.05.
mm. When this stent was mounted on a delivery balloon, the outer diameter of the stent was about 1.0 mm, the peak / valley width of the corrugated element was 0.36 mm, and the largest wave height of the connecting member was 0.50 mm. The wave height was larger than the peak / valley width of the wave element.
The length of the linear long segment of the corrugated element is 1.69.
mm, the length of the short segment was 1.29 mm, and the distance between adjacent corrugations was 0.76 mm. The total extension of each connecting member was 4.75 mm. And
The straight-line distance between the peaks or the valleys of adjacent wave-shaped elements was 2.3 mm.

The peripheral length of the gap 21 of the stent is 1
0.34 mm. When this is converted into the diameter of a circle, it is about 3.3 mm. On the other hand, assuming that the peaks are connected by a straight connecting member, the peripheral length of the gap of the stent at that time is 7.56 mm. When this is converted into the diameter of a circle, it is 2.4 mm. Therefore, when the stent of the present invention is used, a balloon of 3.25 mm can be used for the side branch, but when the connecting member is straight, only a balloon of 2.25 mm can be used. In terms of cross-sectional area,
The diameter of 3.25 mm is 2.28 times the diameter of 2.25 mm, which is advantageous in this respect. It is thought that the fact that the width of the corrugated connection member is small contributes to easy deformation along the balloon when the balloon is expanded.

[0043]

According to the stent of the present invention, in particular, the expansion member is constituted by a corrugated element spirally arranged, and the corrugated element adjacent in the longitudinal direction of the stent has a corrugated connection having a plurality of waves. Because they are connected by members, they have excellent axial flexibility before and after expansion. Therefore, when delivering the stent of the present invention,
Restenosis at the edge of the stent is possible because it can deliver difficult lesions such as bent and calcified ones, and the stent has the flexibility to bend easily when placed in a bent lesion. Can be expected to be prevented. Furthermore, the stent of the present invention has a corrugated connecting member having a plurality of waves, and has an advantage that a larger balloon can be applied to the side branch since its total length is longer than a straight line.

[Brief description of the drawings]

FIG. 1 is an enlarged development view of a stent according to an embodiment of the present invention before expansion.

FIG. 2 is an expanded view showing a part of the stent shown in FIG. 1 in an enlarged manner.

FIG. 3 is an expanded view of the stent shown in FIG. 1 after expansion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Expansion member 12 ... Corrugated connection member 111 ... Corrugated element 111a ... Linear long segment of corrugated element 111b ... Linear short segment of corrugated element 111c ... Curved segment of corrugated element 121 ... Corrugated mountain connection element 122: corrugated valley connecting element 121b, 122b: small wave of corrugated connecting member 121c, 122c: large wave of corrugated connecting member 21, 22: gap when stent is expanded M: peak of corrugated element V: corrugated element Valley X: axial direction of the stent

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C167 AA45 AA55 BB01 BB11 BB12 CC09 CC20 CC21 CC22 CC26 FF05 GG21 HH17 HH18

Claims (8)

[Claims] A first outer diameter that is formed in a tubular shape as a whole and that can be inserted into a living body lumen, and that has a first outer diameter when a radially outward expanding force is applied inside the first outer diameter; A stent expandable to a second outer diameter greater than the diameter, the expansion member comprising a corrugated element arranged to wrap around the longitudinal axis of the stent in a spiral manner, and the corrugated element of the expansion member. A plurality of corrugated connecting members that connect the peaks and the valleys and / or the valleys and the valleys. Appearing, each corrugated coupling member having a plurality of waves and having a greater amplitude wave than the other waves in the gap between adjacent corrugated elements in the axial direction of the stent. Possible stent. 2. The method according to claim 1, wherein the ridges and valleys and the valleys of substantially all of the corrugated elements adjacent to each other in the longitudinal axis direction of the stent are connected by a corrugated connecting member. The stent according to any of the preceding claims. 3. The stent according to claim 1, wherein the corrugated elements adjacent to each other in the longitudinal axis direction of the stent are arranged so as to cause substantially no phase difference in the waves. 4. The stent according to claim 1, wherein the width of each corrugated connecting member is equal to or less than half the width of the corrugated element. 5. The width of each corrugated connecting member is 0.03 mm or more.
4. The stent of claim 3, wherein the stent is in the range of 0.08mm. 6. The largest wave in each corrugated connection member, with the stent having the first outer diameter,
The stent according to any one of claims 1 to 5, wherein the width is greater than the width of the peaks or valleys of the corrugated element. 7. The total extension of the corrugated connecting member is at least 1.3 times the linear distance between peaks or valleys of corrugated elements adjacent in the longitudinal direction of the stent. The stent according to any one of claims 1 to 6, wherein 8. The stent according to claim 1, wherein the width of the gap between the corrugated elements adjacent in the longitudinal direction of the stent is 0.4 to 1.7 mm. Stent.