JP4188431B2 - Stent - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stent that is inserted into a human tubular organ, such as a blood vessel or a ureter, and maintains the lumen of the tubular organ in an open state.
[0002]
[Prior art]
For example, in the treatment of myocardial infarction or the like, a treatment for preventing occlusion of a blood vessel is performed by inserting an expander called a stent into a narrowed portion of the blood vessel. Further, in the treatment of ureteral stones and the like, a stent may be used to maintain the ureter in an expanded state so that the stones are easily discharged.
[0003]
In general, a stent is attached to the outer periphery of the distal end of a balloon catheter in a reduced diameter shape, inserted into the occluded affected area through a guide catheter, and then the balloon of the balloon catheter is inflated and forcibly expanded and placed in the occluded affected area in that state. To expand the tubular organ.
[0004]
As an example of a conventional stent, Japanese Patent Laid-Open No. 6-181993 discloses a longitudinal direction having a plurality of cylindrical elements that are independently expandable in the radial direction and interconnected so as to be substantially aligned with a common axis. A flexible stent is disclosed. In addition, as an example, a plurality of cylindrical elements that extend in the circumferential direction in a waveform and are connected in an annular manner are arranged at predetermined intervals in the axial direction, and a part of these cylindrical elements extends in the axial direction. The concatenation is disclosed.
[0005]
[Problems to be solved by the invention]
However, the stent disclosed in Japanese Patent Laid-Open No. 6-181993 has a problem that a strong expansion force is required because the entire cylinder cannot be expanded unless each cylindrical element is expanded.
[0006]
In addition, the individual cylindrical elements can be expanded independently, but the expansion force applied to one cylindrical element is not transmitted to the other cylindrical elements, so the stent is partially However, there is a problem that the entire system is not expanded uniformly.
[0007]
Accordingly, it is an object of the present invention to provide a stent that can be expanded even with a relatively weak expansion force, and that the expansion is made as uniform as possible in the axial direction.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention is a stent formed by cutting a cylindrical metal body into a predetermined pattern, and includes three line portions parallel to the axial direction, and An S-shaped line portion composed of a bent portion connecting the end portions has a corrugated spiral member formed by connecting a plurality of slanted portions in the axial direction by the connecting line portion. A plurality of spiral members arranged in parallel in a direction so as to be aligned in a direction, and further, a corrugated circumferential member that connects the spiral members in the circumferential direction is disposed only at both ends, and the plurality of spiral members Each of the both end portions of the stent is connected to the circumferential member at a different angular position when viewed from the axial direction.
[0010]
A second aspect of the present invention is a stent formed by cutting a metal cylindrical body into a predetermined pattern, and includes three line portions parallel to the axial direction and bent portions connecting the end portions of these line portions. And a plurality of S-shaped line portions connected in an axial direction by connecting line portions, and a plurality of spiral members are arranged so that the S-shaped line portions are arranged in the circumferential direction. Arranged in parallel in a multi-spiral shape, and further arranged in three locations, both end portions and intermediate portions, are wavy circumferential members that connect the spiral members in the circumferential direction, and each of the plurality of spiral members Both ends provide a stent characterized by being connected to the circumferential member at different angular positions when viewed from the axial direction.
[0011]
According to a third aspect of the present invention, there is provided the stent according to the first or second aspect, wherein the line width of the portion extending in the circumferential direction is narrower than the portion extending in the axial direction.
[0012]
According to a fourth aspect of the present invention, there is provided the stent according to any one of the first to third aspects, wherein the connecting line portion is narrower than the S-shaped line portion.
[0013]
According to the first aspect of the present invention, when the stent is attached to the outer periphery of the balloon catheter in a reduced diameter state and reaches a target location in the tubular organ of the human body, the balloon catheter is inflated to apply an expansion force. The corrugated portion of the circumferential member connected to at least both ends of the spiral member is opened and expanded in the circumferential direction, and the circumferential interval between the spiral members is widened.
[0014]
Moreover, since the circumference of the cylinder of the stent increases with the expansion, a force extending in the circumferential direction acts on the spiral member itself. Since this force acts to pull the spiral member, it acts as a force that evenly opens each S-shaped line portion of the spiral member. For this reason, the expansion force is transmitted in the axial direction, and the stent can be expanded evenly as a whole.
[0015]
Furthermore, the force of stretching the spiral member in the circumferential direction does not require a very strong force, so that the balloon catheter pressing force required for stent expansion can be relatively small, and the expansion operation can be performed easily and quickly. It can be carried out.
[0016]
In addition, since the spiral member is connected to the circumferential member at different angular positions when viewed from the axial direction, when the circumferential member expands and its circumferential length increases, a force pulling both ends of the spiral member acts. Thus, the spiral member can be effectively expanded in the circumferential direction.
[0017]
According to the second aspect of the present invention, since the spiral member is connected to the circumferential member at both end portions and the intermediate portion thereof, the expansion holding force of the intermediate portion is improved, and the expansion is uniformly maintained as a whole. Power can be granted.
[0018]
According to the third aspect of the present invention, the portion extending in the circumferential direction is narrower than the portion extending in the axial direction, thereby reducing the corrugated portion of the circumferential member and the S-shaped line portion of the spiral member. It can be opened easily and can be expanded with a relatively small expansion force.
[0019]
According to the fourth aspect of the present invention, since the line width of the connecting line portion is narrower than that of the S-shaped line portion, the spiral member can be easily extended in the circumferential direction, and further expanded. be able to.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The material of the stent of the present invention is not particularly limited, but for example, a metal made of stainless steel, tantalum, titanium, platinum, gold, tungsten, shape memory alloy, or the like is preferable. The stent of the present invention can be manufactured, for example, by producing a metal cylinder as described above and cutting the cylinder into a predetermined pattern by means such as etching or laser processing.
[0021]
1-4, an embodiment of a stent according to the present invention is shown. FIG. 1 is a perspective view of a reduced diameter state, FIG. 2 is a partially developed view of the reduced diameter state, FIG. 3 is an explanatory view showing a change in peripheral length during expansion, and FIG. 4 is a partially developed view of the expanded state.
[0022]
As shown in FIGS. 1 and 2, the stent 11 has a spiral formed of an S-shaped line portion 12 bent in an S-shape and a connecting line portion 13 that connects the S-shaped line portion 12 obliquely in the axial direction. A member 14 is provided. The S-shaped line portion 12 includes three line portions 12a that are parallel to the axial direction, and a bent portion 12b that connects the ends of these line portions 12a. The connecting line portion 13 connects the end portions of the S-shaped line portion 12 obliquely in the axial direction, whereby the spiral member 14 extends spirally along the cylindrical peripheral surface of the stent 11. A plurality of such spiral members 14 are arranged to draw a multiple spiral.
[0023]
Both end portions of each spiral member 14 are connected to a circumferential member 15 which is formed in a waveform and extends in the circumferential direction, and is connected in a ring shape. The circumferential member 15 is corrugated and can be expanded in the circumferential direction, and the end portion of the stent is formed by a rounded bent portion to prevent damage to the inner wall of the tubular organ.
[0024]
As shown in FIG. 3, when the stent 11 is viewed in the axial direction, one end of the spiral member 14 is located at a point a on the circumference, and the other end is at a different angular position. It is located at a certain point b. For this reason, when the diameter is expanded by being pressed from the inside by the balloon catheter, one end of the spiral member 14 is located at the point a ′ on the expanded circumference, and the other end is expanded. Located at point b ′ on the circumference.
[0025]
As a result, the circumferential length of the spiral member 14 changes from L ₁ to L ₂ . This means that both end portions of the spiral member 14 are pulled in the circumferential direction with a length of L ₂ -L ₁ . Since the helical member 14 is composed of an S-shaped line portion 12 bent in an S-shape and a connecting line portion 13 that connects the S-shaped line portion 12 obliquely in the axial direction, this tensile force is The S-shaped line portions 12 that work equally on the character line portions 12 and are obliquely arranged in the axial direction are evenly opened and expanded in the radial direction. Therefore, the stent 11 can be expanded evenly in the axial direction.
[0026]
Further, when the stent 11 is expanded, as shown in FIG. 4, the corrugated portion of the circumferential member 15 that connects both ends of each spiral member 14 opens and expands in the radial direction, and the spacing between the spiral members 14. And the S-shaped line portion 12 of each spiral member 14 is opened as described above, and the portion constituted by the spiral member 14, that is, the intermediate portion of the stent 11, is also expanded in the radial direction.
[0027]
As described above, in the stent 11 of the present invention, the circumferential members 15 arranged at both ends are expanded, and accordingly, the interval between the spiral members 14 is increased, and a tensile force is applied to each spiral member 14. When the S-shaped line 12 is opened, the entire stent 11 is expanded. Therefore, the stent 11 can be expanded on the average in the axial direction with a relatively small expansion force as compared with the stent described in JP-A-6-181993. Is possible.
[0028]
The surface of the wire constituting the stent 11 is preferably covered with a polyfluorinated ethylene resin, a heparin-containing resin, a hydrophilic resin, or the like in order to prevent thrombus from adhering.
[0029]
Next, the usage method of this stent 11 is demonstrated as an example applied to the stenosis part of a blood vessel.
[0030]
First, a guide catheter is inserted percutaneously into a blood vessel by a well-known Seldinger method, and the tip of the guide catheter reaches the vicinity of the stenosis. Then, the stent 11 is mounted on the outer periphery of the balloon at the distal end portion of the balloon catheter in a reduced diameter state, and the balloon catheter is guided into the blood vessel through the guide catheter.
[0031]
Further, using the guide wire inserted into the balloon catheter as a guide, the balloon catheter is further pushed forward, and the stent 11 attached to the distal end portion thereof is disposed in the stenosis portion. In this state, a liquid such as physiological saline is injected into the balloon through the balloon catheter, and the balloon 11 is expanded to expand the stent 11.
[0032]
Thereafter, the liquid in the balloon is extracted to deflate the balloon, and the balloon catheter is extracted from the inner periphery of the stent 11 to place the stent 11 in place. Thus, the stent 11 can be used to expand a stenosis of a blood vessel to prevent or treat myocardial infarction or cerebral infarction.
[0033]
In the stent 11 of the present invention, a plurality of corrugated spiral members 14 formed by connecting a plurality of S-shaped line portions 12 obliquely in the axial direction by connecting line portions 13 are arranged in a multiple spiral shape in parallel. Therefore, the arrangement density of the wires can be increased and the inner wall of the blood vessel can be supported on an average with a wide contact area, thereby preventing restenosis of the blood vessel.
[0034]
5 and 6 show another embodiment of the stent according to the present invention. In addition, since the stent of this Example is not fundamentally different from the Example of the said FIGS. 1-4, only the helical member 14 which is especially different parts is partially shown.
[0035]
In this embodiment, as shown in FIG. 5, in the S-shaped line portion 12 of the spiral member 14, the bent portion 12b that connects these line portions 12a rather than the width A of the line portions 12a parallel to the axial direction, that is, The width B of the line portion along the circumferential direction is narrowed.
[0036]
Specifically, the width A of the line portion 12a parallel to the axial direction is preferably 0.1 to 0.5 mm, and the width B of the bent portion 12b along the circumferential direction is preferably 0.05 to 0.4 mm. Further, not only in the spiral member 14 but also in the circumferential member 15, it is preferable that the line width of the portion extending in the circumferential direction is narrower than the portion extending in the axial direction, as described above.
[0037]
The thickness of the spiral member 14 and the circumferential member 15 constituting the stent is not particularly limited, but is preferably 50 to 200 μm in view of the balance between the flexibility in the axial direction and the expansion holding force at the time of expansion. .
[0038]
In this stent, since the bent portion 12b extending in the circumferential direction of the S-shaped line portion 12 is easily bent when expanded with a balloon catheter, the S-shaped line portion 12 is easily opened as shown in FIG. Thus, the stent can be easily expanded.
[0039]
7 and 8 show still another embodiment of the stent according to the present invention. Since the stent of this embodiment is basically the same as the embodiment of FIGS. 1 to 4, only the spiral member 14 which is a particularly different portion is partially shown.
[0040]
In this embodiment, as shown in FIG. 7, in the S-shaped line portion 12 of the spiral member 14, a bent portion 12b that connects these line portions 12a rather than the width A of the line portion 12a parallel to the axial direction, that is, The width B of the line portion along the circumferential direction is narrowed, and the line width D of the intermediate portion of the connecting portion 13 is also narrowed.
[0041]
More specifically, the width of the line portion 12a parallel to the axial direction of the S-shaped line portion 12 is A, the width of the bent portion 12b connecting these line portions 12a is B, and the width of both end portions 13a of the connecting portion 13 is. When C and the width of the intermediate portion 13b of the connecting portion 13 are D, A> B and A>C> D are satisfied. The width of C is preferably 0.07 to 0.5 mm, and the width of D is preferably 0.05 to 0.4 mm.
[0042]
In this stent, when expanded with a balloon catheter, the bent portion 12b extending in the circumferential direction of the S-shaped line portion 12 is easily bent, and the connecting portion 13 is also easily changed into a free shape. As shown in FIG. 8, the S-shaped line portion 12 is easily and effectively opened, and the stent is easily expanded.
[0043]
FIG. 9 shows still another embodiment of the stent of the present invention. It should be noted that substantially the same parts as those in the embodiment shown in FIGS.
[0044]
The stent 31 of this embodiment is similar to the embodiment of FIGS. 1 to 4 in that a plurality of spiral members 14 composed of the S-shaped line portion 12 and the connecting line portion 13 are formed in parallel to form a multiple spiral shape. It is the same. However, in this stent 31, corrugated circumferential members 15 a and 15 b that connect both end portions of each spiral member 14 are provided, and similarly corrugated circumferential members 15 c that connect the intermediate portion of each spiral member 14 are provided. The point provided is different from the above embodiment.
[0045]
The stent 31 is provided with the circumferential member 15c at the intermediate portion of each spiral member 14, thereby increasing the expansion holding force at the intermediate portion of the stent 31 and is sufficient as a whole even when the stent is long in the axial direction. It is possible to obtain an appropriate extended holding force.
[0046]
Note that the winding direction of the spiral member 14 may be reversed between the right side and the left side with the circumferential member 15c at the intermediate portion as a boundary.
[0047]
【Example】
A metal cylinder made of stainless steel with a diameter of 2 mm, a length of 20 mm, and a wall thickness of 100 μm was laser processed to produce a stent having the shape shown in FIGS. The line width of the spiral member 14 and the circumferential member 15 was 0.2 mm.
[0048]
A balloon catheter was inserted into the stent, water was injected into the balloon, the internal pressure was increased and the balloon was inflated, and the change in the expanded shape of the stent accompanying an increase in the balloon internal pressure was observed. The results are shown in FIGS.
[0049]
10 and 11, the pressure on the right side indicates the internal pressure of the balloon 41, deflate means that the pressure in the balloon 41 has been removed by releasing water, and the final expanded state is that the expanded stent 11 to the balloon 41. It means the state extracted.
[0050]
As shown in FIGS. 10 and 11, as the internal pressure of the balloon 41 is increased, the stent 11 expands to increase its diameter, and is deflated to a maximum of 7.5 atm. When the balloon 41 is removed, the final expanded shape is obtained. The diameter was 5mm.
[0051]
Further, the stent 11 is expanded by opening the waveform of the circumferential member 15 at both ends and extending in the circumferential direction, opening the interval between the spiral members 14, and opening the S-shaped line portion of the spiral member 14. I understand that.
[0052]
【The invention's effect】
As described above, according to the present invention, when the stent is expanded with the balloon catheter, the corrugated portion of the circumferential member connected to at least both ends of the spiral member opens and expands in the circumferential direction. The circumferential interval increases. In addition, since the circumference of the stent increases with this expansion, a force that extends in the circumferential direction also acts on the spiral member itself, and this force acts to pull the spiral member, so that the expansion force is transmitted in the axial direction. Thus, the stent can be expanded evenly as a whole. Furthermore, the force of stretching the spiral member in the circumferential direction does not require a very strong force, so that the balloon catheter pressing force required for stent expansion can be relatively small, and the expansion operation can be performed easily and quickly. It can be carried out.
[Brief description of the drawings]
FIG. 1 is a perspective view of a reduced diameter state showing an embodiment of a stent of the present invention.
FIG. 2 is a partial development view of the stent in a reduced diameter state.
FIG. 3 is an explanatory view showing a change in peripheral length when the stent is expanded.
FIG. 4 is a partial development view of the stent in an expanded state.
FIG. 5 is a partially enlarged view in a reduced diameter state showing another embodiment of the stent of the present invention.
FIG. 6 is a partially enlarged view of the stent in an expanded state.
FIG. 7 is a partially enlarged view in a reduced diameter state showing still another embodiment of the stent of the present invention.
FIG. 8 is a partially enlarged view of the stent in an expanded state.
FIG. 9 is a partial development view in a reduced diameter state showing still another embodiment of the stent of the present invention.
FIG. 10 is a diagram showing a change in an expanded shape with an increase in internal pressure of a balloon when the stent obtained in the example is expanded with a balloon catheter.
FIG. 11 is a diagram showing a change in the expanded shape when the stent is expanded by further increasing the internal pressure of the balloon, and finally the balloon pressure is released and the balloon is extracted.
[Explanation of symbols]
11, 31 Stent 12 S-shaped line part 13 Connecting line part 14 Spiral members 15, 15a, 15b, 15c Circumferential member 41 Balloon

Claims (4)

An S-shape formed by cutting a cylindrical metal body into a predetermined pattern, which is composed of three line portions parallel to the axial direction and bent portions connecting the end portions of these line portions. A line portion has a corrugated spiral member formed by connecting a plurality of slanted portions in the axial direction by a connecting line portion. Further, corrugated circumferential members that connect the spiral members in the circumferential direction are disposed only at both ends, and each end of the plurality of spiral members has a different angle when viewed from the axial direction. A stent connected to the circumferential member in position. An S-shape formed by cutting a cylindrical metal body into a predetermined pattern, which is composed of three line portions parallel to the axial direction and bent portions connecting the end portions of these line portions. A line portion has a corrugated spiral member formed by connecting a plurality of slanted portions in the axial direction by a connecting line portion. Further, wave-shaped circumferential members that connect the helical members in the circumferential direction are arranged at three locations, both end portions and an intermediate portion, and both end portions of the plurality of spiral members are arranged in the axial direction. A stent characterized by being connected to the circumferential member at different angular positions when viewed.   The stent according to claim 1 or 2, wherein the line width of the portion extending in the circumferential direction is narrower than the portion extending in the axial direction.   The stent according to any one of claims 1 to 3, wherein the connecting line portion is narrower than the S-shaped line portion.

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