JP5612985B2 - Stent, stent system including the same, and stent manufacturing method - Google Patents

Description

  The present invention relates to a stent used for treatment of a stenosis in a living organ, a stent system including the stent, and a method for manufacturing the stent.

  Traditionally, in the treatment of myocardial infarction and angina pectoris, stents have been widely used to expand and maintain the lumen of the coronary artery lesion (stenosis), other blood vessels, bile ducts, trachea, It may be used in the same way for the improvement of strictures formed in living organs such as the esophagus, urethra, and other organs.

  Generally, stents include self-expanding stents and balloon expandable stents. The balloon-expandable stent is placed in a desired stenosis while being mounted around the balloon of the catheter, and is expanded by expanding the balloon, and is closely attached to and held on the inner wall of the lumen.

  As such a balloon-expandable stent, one that can be expanded radially outward by arranging a plurality of wavy annular bodies in the axial direction is known (for example, see Patent Document 1).

JP 2008-86463 A

  It is desirable that the stent be thin in order to make the outer diameter when mounted around the balloon as small as possible to facilitate insertion into the stenosis and to make the lumen of the stenosis as wide as possible. However, when the stent is thinned, the strength is reduced, so that the resistance force (radial force) to the force that the stenosis portion is contracting is reduced. As a result, restenosis after treatment may occur. In addition, when the stent is made thin, a problem that a part (curved portion) of the wavy annular body rises during expansion may occur.

  As a countermeasure against such a problem, it is conceivable that the stent is made of a high-strength material to make it thin, but in this case, since the yield stress becomes high, the stent cannot be sufficiently plastically deformed during expansion. is there. In an extreme case, the stent may be deformed only within the elastic deformation region during expansion, which may induce restenosis.

  The present invention has been made in consideration of such problems, and even when it is formed thin, it can suppress the rising of the curved portion and can increase the radial force during expansion, It is another object of the present invention to provide a stent, a stent system including the stent, and a stent manufacturing method that can suppress a phenomenon called so-called recoil, in which a stent that has once expanded contracts itself.

The invention specified in claim 1 of the present application is a stent that is formed by a cylindrical body having a linear portion having a curved portion and is expandable radially outward of the cylindrical body, and the curved portion has an outer periphery. The strength of the intermediate part located between the part and the inner peripheral part is set higher than the strength of the outer peripheral part and the inner peripheral part, and the outer peripheral part, the inner peripheral part and the intermediate part are made of the same metal. It is formed integrally .

  According to the invention specified in claim 1 of the present application, the strength of the intermediate portion of the curved portion is set to be higher than the strength of the outer peripheral portion and the inner peripheral portion. Compared with the case where the strength of the inner peripheral portion is set, the strength of the curved portion can be increased. Thereby, even if it is a case where a stent is formed in thin wall, at the time of expansion, the curling-up of the said curved part can be suppressed and radial force can be raised. In addition, when the stent is expanded, the strength of the intermediate portion with less strain (deformation amount) is increased and the strength of the outer peripheral portion and inner peripheral portion with greater strain (deformation amount) is reduced. Even if the part is in the elastic deformation region, the outer peripheral part and the inner peripheral part can be reliably plastically deformed. Thereby, recoil can be suppressed low.

  The invention specified in claim 2 of the present application is the stent according to claim 1, wherein the linear portion has a straight portion, and the straight portion has an extending direction and a radial direction of the cylindrical body. The strength of the intermediate portion located between both end portions in the direction orthogonal to is set higher than the strength of the both end portions.

  According to the invention specified in claim 2 of the present application, since the strength of the intermediate portion of the straight portion is set higher than the strength of the both end portions, the radial force can be further increased and the recoil can be further lowered. It can be suppressed.

  The invention specified in claim 3 of the present application is the stent according to claim 1 or 2, wherein the cylindrical body is formed by connecting a plurality of annular bodies having the plurality of curved portions in the axial direction. It is characterized by that.

  According to the invention specified in claim 3 of the present application, a plurality of annular bodies having a plurality of curved portions are connected in the axial direction to form a cylindrical body, so that the stent is surely expanded radially outward. Can do.

  The invention specified in claim 4 of the present application is a stent system comprising a tubular shaft, an expandable balloon provided on the shaft, and a stent mounted on the balloon, wherein the stent is The stent according to any one of claims 1 to 3.

  According to the invention specified in claim 4 of the present application, the same effects as those described in claims 1 to 3 described above can be obtained.

The invention specified in claim 5 of the present application is a stent manufacturing method for manufacturing a radially expandable stent by altering a metal cylindrical body having a linear portion having a curved portion. a first annealing step of annealing the periphery portion of the curved portion, performing a second annealing step of annealing the inner peripheral portion positioned so as to sandwich the intermediate portion between the outer peripheral portion of the curved portion Thus, the strength of the intermediate portion is made higher than the strength of the outer peripheral portion and the inner peripheral portion .

  According to the invention specified in claim 5 of the present application, since the distortion of the outer peripheral portion and the inner peripheral portion of the curved portion is removed by the first annealing step and the second annealing step, the outer peripheral portion and the inner peripheral portion are softened. To do. Thereby, the intensity | strength of the intermediate part located between the said outer peripheral part and the said inner peripheral part can be made higher than the intensity | strength of the said outer peripheral part and the said inner peripheral part which were annealed. Therefore, there exists an effect similar to the effect described in Claim 1 mentioned above.

  The invention specified in claim 6 of the present application is the stent manufacturing method according to claim 5, wherein the cylindrical body has age-hardening properties, and the cylindrical body is subjected to the first annealing step before the first annealing step. And aging treatment.

  According to the invention specified in claim 6 of the present application, by performing the aging treatment, fine precipitates appear on the cylindrical body, so that the strength of the entire cylindrical body can be increased. Thereafter, since the strength of the outer peripheral portion and the inner peripheral portion of the curved portion is reduced, the strength of the intermediate portion of the curved portion can be made higher than the strength of the outer peripheral portion and the inner peripheral portion.

  The invention specified in claim 7 of the present application is the stent manufacturing method according to claim 5, wherein the cylindrical body has age-hardening properties, and in the first annealing step, the outer peripheral portion is annealed. In the second annealing step, another part of the intermediate part is age-hardened by heat generated when the inner peripheral part is annealed. .

  According to the invention specified in claim 7 of the present application, since the intermediate portion of the curved portion is age-hardened using the heat generated when the outer peripheral portion and the inner peripheral portion of the curved portion are annealed, annealing is performed. Compared with the case where an aging treatment is performed before the cycle time, the cycle time can be shortened.

  The invention specified in claim 8 of the present application is the stent manufacturing method according to any one of claims 5 to 7, wherein the linear portion has a straight portion, and among the straight portions, A third annealing step for annealing one end in a direction orthogonal to the extending direction and the radial direction of the cylindrical body, and of the linear portion, in the direction orthogonal to the extending direction and the radial direction of the cylindrical body. And performing a fourth annealing step of annealing the other end.

  According to the invention specified in claim 8 of the present application, the distortion at both ends of the linear portion is removed by the third annealing step and the fourth annealing step, so that the both end portions are softened. Thereby, the intensity | strength of the intermediate part of the said linear part can be made higher than the intensity | strength of this both ends. Therefore, there exists an effect similar to the effect described in Claim 2 mentioned above.

  The invention specified in claim 9 of the present application is characterized in that, in the stent manufacturing method according to claim 8, the first to fourth annealing steps are performed using laser light.

  According to the invention specified in claim 9 of the present application, it is possible to reliably and easily anneal the outer peripheral portion and the inner peripheral portion of the curved portion and both end portions of the linear portion.

The invention specified in claim 10 of the present application is a stent manufacturing method for manufacturing a radially expandable stent by modifying a metal cylindrical body having a linear portion having a curved portion. The cylindrical body has quench hardenability, and an annealing step for annealing the cylindrical body, and heating an intermediate portion located between the outer peripheral portion and the inner peripheral portion of the curved portion, The intermediate structure is martensitic transformed so that the strength of the intermediate part is higher than the strength of the outer peripheral part and the inner peripheral part .

  According to the invention specified in claim 10 of the present application, after annealing the cylindrical body, the intermediate portion of the curved portion is heated to martensite its crystal structure. The strength of the outer peripheral part and the inner peripheral part of the part can be made higher. Thereby, there exists an effect similar to the effect described in Claim 1 mentioned above.

  The invention specified in claim 11 of the present application is the stent manufacturing method according to claim 10, wherein the linear portion has a straight portion, and the extension of the straight portion after the annealing step. The intermediate structure located between both ends in the direction and the direction perpendicular to the radial direction of the cylindrical body is heated to transform the crystal structure of the intermediate part into a martensite.

  According to the invention specified in claim 11 of the present application, after annealing the cylindrical body, the intermediate portion of the linear portion is heated to martensite its crystal structure. It can be made higher than the strength of both ends of the part. Thereby, there exists an effect similar to the effect described in Claim 2 mentioned above.

  The invention specified in claim 12 of the present application is characterized in that heating of the intermediate portion of the curved portion and the intermediate portion of the linear portion is performed using laser light.

  According to the invention specified in claim 12 of the present application, it is possible to reliably and easily heat the intermediate portion of the curved portion and the intermediate portion of the straight portion.

  As described above, according to the present invention, since the strength of the intermediate portion of the curved portion can be made higher than the strength of the outer peripheral portion and the inner peripheral portion, even when the stent is formed thin, The curling up of the music part can be suppressed and the radial force can be increased. Moreover, since the said outer peripheral part and the said inner peripheral part can be reliably plastically deformed at the time of expansion, recoil can be restrained low.

1 is an overall configuration diagram of a stent system according to an embodiment of the present invention. FIG. 2 is an enlarged side view of a stent constituting the stent system shown in FIG. 1 and its periphery. FIG. 3 is a partially omitted enlarged view of the stent shown in FIG. 2. It is a perspective view which shows the linear pattern of the 1st annular body of the stent shown in FIG. It is process drawing for demonstrating the 1st and 3rd manufacturing method of the stent which concerns on this Embodiment. It is a side view of a processing cylinder. It is explanatory perspective view which shows the state which is performing the 1st laser irradiation with respect to the 1st annular body of a process cylindrical body. FIG. 8A is a cross-sectional view for explaining the laser conditions of the first laser irradiation for the first linear portion in the first manufacturing method, and FIG. 8B is the first laser for the first curved portion in the first manufacturing method. It is sectional drawing for demonstrating the laser conditions of irradiation. It is explanatory perspective view which shows the state which is performing the 2nd laser irradiation with respect to the 1st annular body of a process cylindrical body. It is process drawing for demonstrating the 2nd manufacturing method of the stent which concerns on this Embodiment. FIG. 11A is a cross-sectional view for explaining the laser conditions of the first laser irradiation for the first straight part in the third manufacturing method, and FIG. 11B is the first laser for the first curved part in the third manufacturing method. It is sectional drawing for demonstrating the laser conditions of irradiation. It is process drawing for demonstrating the 4th manufacturing method of the stent which concerns on this Embodiment. It is an explanatory perspective view showing the state where laser irradiation is performed to the 1st annular body in the 4th manufacturing method. FIG. 14A is a cross-sectional view for explaining laser conditions for laser irradiation on the first straight portion in the fourth manufacturing method, and FIG. 14B is for explaining laser conditions for laser irradiation on the first curved portion in the fourth manufacturing method. FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a stent according to the present invention and a stent system including the stent will be described in detail with reference to the accompanying drawings with preferred embodiments.

  In the stent system according to the present invention, a long shaft is inserted into a living organ, for example, a coronary artery, and a balloon provided on the distal end side of the stent system is expanded at a lesion (stenosis) to expand and widen the stenosis. It has a so-called balloon catheter to be treated, and is used for stent delivery to place a stent mounted around the balloon in a desired stenosis. Of course, the present invention is also applied to the improvement of lesions formed in living organs other than those for coronary arteries, such as other blood vessels, bile ducts, trachea, esophagus, urethra, and other organs. Is possible.

  As shown in FIG. 1, the stent system 10 according to the present embodiment includes a thin and long shaft 12, a hub 14 provided on the proximal end side of the shaft 12, and a distal end side of the shaft 12. A provided balloon 16 and a stent 18 mounted on the balloon 16 are provided. In FIG. 1, the right side of the shaft 12 is referred to as a “base end (rear end)” side, and the left side of the shaft 12 is referred to as a “front end” side.

  The shaft 12 is formed in a cylindrical shape and is made of a highly slidable resin or the like, and allows the operator to smoothly insert it into a living organ such as a blood vessel while grasping or operating the proximal end side thereof. It has moderate flexibility and moderate strength. Although not shown in detail, the shaft 12 has a guide wire lumen through which a guide wire 20 for guiding the stent system 10 to the stenosis of the coronary artery is inserted, and a balloon for guiding the expansion fluid into the balloon 16. Lumen and are formed.

  The balloon 16 is liquid-tightly joined to the shaft 12 at a position slightly closer to the proximal end side than the distal end of the shaft 12. The balloon 16 can be folded and expanded by changing the internal pressure. As shown in FIG. 2, the balloon 16 can be expanded into a cylindrical shape (cylindrical shape) by an expansion fluid injected into the inside through the balloon lumen. It has a cylindrical portion 16b, a distal tapered portion 16a that gradually decreases in diameter on the distal end side of the cylindrical portion 16b, and a proximal tapered portion 16c that gradually decreases in diameter on the proximal end side of the cylindrical portion 16b.

  The stent 18 is a so-called balloon expandable stent that expands (plastically deforms) by the expansion force of the balloon 16, and is mounted on the tubular portion 16 b of the balloon 16. The material constituting the stent 18 is preferably a biocompatible metal, for example, an iron base alloy such as stainless steel, tantalum (tantalum alloy), platinum (platinum alloy), gold (gold alloy), cobalt base alloy, A cobalt chromium alloy, a titanium alloy, a niobium alloy, etc. are mentioned.

  The stent 18 includes first to eighth annular bodies 22a, 22b, 22c, 22d, 22e, 22f, 22g, and 22h arranged in the axial direction thereof, and the first annular body 22a, the second annular body 22b, and the second annular body. 22b and third annular body 22c, third annular body 22c and fourth annular body 22d, fourth annular body 22d and fifth annular body 22e, fifth annular body 22e and sixth annular body 22f, and sixth annular body 22f The seventh annular body 22g and the seventh annular body 22g and the eighth annular body 22h are connected to each other by a plurality of connecting portions 24. In FIG. 1, the shape of the stent 18 is simplified and displayed as a mesh.

  The first annular body 22a is formed by connecting a plurality of linear patterns 26 in an annular shape. Similarly, the second annular body 22b has a plurality of linear patterns 28, the third annular body 22c has a plurality of linear patterns 30, and the fourth annular body 22d has a plurality of linear patterns 32, a fifth annular pattern. The body 22e has a plurality of linear patterns 34, the sixth annular body 22f has a plurality of linear patterns 36, the seventh annular body 22g has a plurality of linear patterns 38, and the eighth annular body 22h has a plurality of linear patterns. 40 are connected to each other.

  As shown in FIGS. 3 and 4, the linear pattern 26 is formed in a shape approximate to an M shape by a metal wire (linear portion) 42 having substantially the same width. In FIG. 3, for convenience, one linear pattern 26 is displayed with a thick line.

  The metal wire 42 is formed in a thin wall having a rectangular cross section, and its width is set, for example, to about 100 [μm], and its thickness is set, for example, between 1 [μm] and 100 [μm]. Is done. In addition, the width | variety and thickness of the metal wire 42 can be changed suitably.

  The linear pattern 26 includes a first curved portion 46 connected to one end of the first straight portion 44 extending in one direction, and an extended portion extending to the other side of the stent 18 while being bent gently and connected to the first curved portion 46. 48, a second curved portion 50 connected to the other end of the extending portion 48, a second straight portion 52 extending to one side of the stent 18 connected to the second curved portion 50, and the second straight portion 52 A third curved portion 54 connected to one end, a third straight portion 56 connected to the third curved portion 54 and extending to the other side of the stent 18, and a fourth curved portion 58 connected to the other end of the third straight portion 56. And have. The fourth curved portion 58 is continuous with the other end of the first straight portion 44 of the adjacent linear pattern 26.

  The first straight portion 44 has a strength of the intermediate portion 44c located between both ends 44a and 44b in the extending direction and the direction orthogonal to the radial direction of the stent 18 (width direction of the first straight portion 44). It is set higher than the strength of both end portions 44a and 44b.

  The first curved portion 46 is set such that the strength of the intermediate portion 46c located between the outer peripheral portion 46a and the inner peripheral portion 46b is higher than the strength of the outer peripheral portion 46a and the inner peripheral portion 46b.

  The extending portion 48 can be approximated by a straight line, and an intermediate portion 48c located between both end portions 48a and 48b in the extending direction and the direction orthogonal to the radial direction of the stent 18 (width direction of the extending portion 48). Is set higher than the strength of the both end portions 48a and 48b. The extending portion 48 may be linear.

  The second curved portion 50 is set such that the strength of the intermediate portion 50c located between the outer peripheral portion 50a and the inner peripheral portion 50b is higher than the strength of the outer peripheral portion 50a and the inner peripheral portion 50b.

  The strength of the intermediate portion 52c located between the end portions 52a, 52b of the second straight portion 52 in the extending direction and the direction orthogonal to the radial direction of the stent 18 (width direction of the second straight portion 52) is It is set higher than the strength of both end portions 52a and 52b.

  The strength of the intermediate portion 54c located between the outer peripheral portion 54a and the inner peripheral portion 54b is set higher than the strength of the outer peripheral portion 54a and the inner peripheral portion 54b.

  The strength of the intermediate portion 56c located between the end portions 56a, 56b of the third linear portion 56 in the extending direction and the direction orthogonal to the radial direction of the stent 18 (width direction of the third linear portion 56) is It is set higher than the strength of both end portions 56a, 56b.

  The strength of the intermediate portion 58c located between the outer peripheral portion 58a and the inner peripheral portion 58b is set higher than the strength of the outer peripheral portion 58a and the inner peripheral portion 58b.

  In the linear pattern 26 configured as described above, the lengths of the first straight portion 44, the extending portion 48, the second straight portion 52, and the third straight portion 56 can be arbitrarily set.

  Since the linear patterns 28, 30, 32, 34, 36, 38, and 40 have the same configuration as the linear pattern 26 described above, detailed description thereof is omitted.

  Next, four manufacturing methods (first manufacturing method, second manufacturing method, third manufacturing method, and fourth manufacturing method) of the stent 18 configured as described above will be described.

(First manufacturing method)
First, the 1st manufacturing method of the stent 18 which concerns on this Embodiment is demonstrated, referring FIGS.

  In the first manufacturing method, first, a metal tube having a predetermined size is produced (step S1 in FIG. 5). In addition, what is necessary is just to produce a metal tube by, for example, forming a long metal tube by drawing a metal material (not shown), and cutting the long metal tube into a predetermined length. . In this case, the metal tube is work hardened. As a material of the metal tube (metal material), for example, the same material as that constituting the stent 18 described above may be used.

  Next, as shown in FIG. 6, the processing cylinder (cylindrical body) 100 is produced by shaping the peripheral surface of the metal tube into a predetermined shape (step S2). Specifically, for example, by removing an unnecessary portion of the peripheral surface of the metal tube by an etching method using a chemical, a mechanical polishing method, a laser processing method, or the like, the shape of the stent 18 described above was supported. A processed cylindrical body 100 having a shape is produced.

  That is, the processing cylinder 100 includes first to eighth annular bodies 102a, 102b, 102c, 102d, 102e, 102f, 102g, and 102h arranged in the axial direction thereof, and the first annular body 102a and the second annular body 102b, Second annular body 102b and third annular body 102c, third annular body 102c and fourth annular body 102d, fourth annular body 102d and fifth annular body 102e, fifth annular body 102e and sixth annular body 102f, sixth Each of the annular body 102f and the seventh annular body 102g, and the seventh annular body 102g and the eighth annular body 102h are connected by a plurality of connecting portions 24.

  Thereafter, the machining cylinder 100 is held by an arm such as a robot (not shown). Then, the first laser irradiation is performed on the first annular body 102a while controlling the position of the processing cylinder 100 by the robot (step S3).

  In this step, as shown in FIG. 7, in each of the plurality of linear patterns 106 of the first annular body 102a, one end portion 108a of the first linear portion 108, the outer peripheral portion 110a of the first curved portion 110, and the extension The other end 112b of the portion 112, the inner peripheral portion 114b of the second curved portion 114, one end 116a of the second straight portion 116, the outer peripheral portion 118a of the third curved portion 118, and the other of the third straight portion 120 The laser beam L is irradiated so as to pass through the end portion 120b and the inner peripheral portion 122b of the fourth curved portion 122.

  The laser beam L is output from a laser device 200 capable of setting laser conditions such as a laser output and a spot diameter, and is irradiated on the outer peripheral surface of the processing cylindrical body 100 (linear pattern 106). For example, when irradiating one end portion 108a of the first linear portion 108 with the laser light L, the spot diameter d1 of the laser light L is set to substantially half of the width W1 of the end portion 108a, and the laser output is The end portion 108a is set to a temperature at which the end portion 108a is annealed, and the robot moves the position of the processing cylinder 100 so that the central axis of the laser beam L is located at the center in the width direction of the end portion 108a. (See FIG. 8A).

  Thereby, the heat of the laser beam L can be diffused throughout the one end portion 108a of the first linear portion 108, so that the end portion 108a can be surely annealed.

  The first straight line is also applied when the other end 112b of the extending portion 112, the one end 116a of the second straight portion 116, and the other end 120b of the third straight portion 120 are irradiated with the laser light L. This is performed in the same manner as the laser irradiation method for one end portion 108a of the portion 108.

  Thereby, the other end 112b of the extending portion 112, the one end 116a of the second straight portion 116, and the other end 120b of the third straight portion 120 can be surely annealed.

  Further, for example, when the laser beam L is irradiated to the outer peripheral portion 110a of the first curved portion 110, the spot diameter d2 of the laser light L is set to substantially half of the width W2 of the outer peripheral portion 110a, and the laser output is The temperature is set so that the outer peripheral portion 110a is annealed, and the robot positions the processing cylinder 100 so that the central axis of the laser beam L is positioned at the approximate center in the width direction of the outer peripheral portion 110a. Control (see FIG. 8B).

  Thereby, since the heat of the laser beam L can be diffused to the outer peripheral portion 110a, the outer peripheral portion 110a can be surely annealed.

  Even when the laser beam L is applied to the inner peripheral portion 114b of the second music portion 114, the outer peripheral portion 118a of the third music portion 118, and the inner peripheral portion 122b of the fourth music portion 122, the first music portion 110 is also irradiated. This is performed in the same manner as the laser irradiation method for the outer peripheral portion 110a.

  Thereby, the outer peripheral part 110a of the first music part 110, the inner peripheral part 114b of the second music part 114, the outer peripheral part 118a of the third music part 118, and the inner peripheral part 122b of the fourth music part 122 are surely annealed. can do.

  As described above, when the first laser irradiation is performed on the first annular body 102a, one end portion 108a of the first linear portion 108 becomes the end portion 44a, and the outer peripheral portion 110a of the first curved portion 110 becomes. The other end 112b of the extending portion 112 is the end 48b, the inner peripheral portion 114b of the second curved portion 114 is the inner peripheral portion 50b, and one end 116a of the second straight portion 116 is the end. The outer peripheral portion 118a of the third curved portion 118 is the outer peripheral portion 54a, the other end portion 120b of the third linear portion 120 is the end portion 56b, and the inner peripheral portion 122b of the fourth curved portion 122 is the inner peripheral portion. 58b (see FIG. 9).

  Subsequently, the second laser irradiation is performed on the first annular body 102a while controlling the position of the processing cylinder 100 by the robot (step S4).

  In this step, as shown in FIG. 9, in each of the plurality of linear patterns 106 of the first annular body 102a, the other end portion 108b of the first linear portion 108, the inner peripheral portion 110b of the first curved portion 110, One end 112a of the extending portion 112, the outer peripheral portion 114a of the second curved portion 114, the other end portion 116b of the second straight portion 116, the inner peripheral portion 118b of the third curved portion 118, and one of the third straight portions 120 The laser beam L is irradiated so as to pass through the end portion 120a of the first and the outer peripheral portion 122a of the fourth curved portion 122.

  The laser beam L is applied to the outer peripheral surface of the processed cylindrical body 100 (linear pattern 106). Laser light is applied to the other end portion 108 b of the first straight portion 108, one end portion 112 a of the extending portion 112, the other end portion 116 b of the second straight portion 116, and the one end portion 120 a of the third straight portion 120. When irradiating L, the same method as the laser irradiation method for the one end portion 108a of the first straight portion 108 described above is performed.

  Further, the laser beam L is applied to the inner peripheral part 110 b of the first music part 110, the outer peripheral part 114 a of the second music part 114, the inner peripheral part 118 b of the third music part 118, and the outer peripheral part 122 a of the fourth music part 122. When irradiating, it carries out similarly to the laser irradiation method with respect to the outer peripheral part 110a of the 1st music part 110 mentioned above.

  Accordingly, the other end portion 108b of the first straight portion 108, the inner peripheral portion 110b of the first curved portion 110, the one end portion 112a of the extending portion 112, the outer peripheral portion 114a of the second curved portion 114, and the second straight portion. The other end portion 116b of 116, the inner peripheral portion 118b of the third curved portion 118, the one end portion 120a of the third straight portion 120, and the outer peripheral portion 122a of the fourth curved portion 122 can be surely annealed.

  As described above, when the second laser irradiation is performed on the first annular body 102a, the other end portion 108b of the first linear portion 108 becomes the end portion 44b and the inner peripheral portion 110b of the first curved portion 110. Is the inner peripheral portion 46b, one end 112a of the extending portion 112 is the end portion 48a, the outer peripheral portion 114a of the second curved portion 114 is the outer peripheral portion 50a, and the other end portion 116b of the second straight portion 116 is the end. In the portion 52b, the inner peripheral portion 118b of the third curved portion 118 is the inner peripheral portion 54b, one end portion 120a of the third straight portion 120 is the end portion 56a, and the outer peripheral portion 122a of the fourth curved portion 122 is the outer peripheral portion. 58a. As a result, the first annular body 102a becomes the first annular body 22a.

  Thereafter, the first and second laser irradiations are performed on each of the second to eighth annular bodies 102b to 102h (step S5). Accordingly, the second annular body 102b is the second annular body 22b, the third annular body 102c is the third annular body 22c, the fourth annular body 102d is the fourth annular body 22d, and the fifth annular body 102e is the fifth. In the annular body 22e, the sixth annular body 102f becomes the sixth annular body 22f, the seventh annular body 102g becomes the seventh annular body 22g, and the eighth annular body 102h becomes the eighth annular body 22h. As a result, the stent 18 according to the present embodiment is completed.

  In the manufacturing method of the stent 18 as described above, the order of the first laser irradiation and the second laser irradiation may of course be reversed. The same applies to the second and third manufacturing methods described later. Moreover, you may utilize heat sources other than a laser beam in the case of annealing. The same applies to the second to fourth manufacturing methods described later.

(Second manufacturing method)
Next, a second method for manufacturing the stent 18 according to the present embodiment will be described with reference to FIG. In the description of the manufacturing method, the detailed description of the same contents as the description of the first manufacturing method is omitted. The same applies to the third and fourth manufacturing methods described later.

  In the second manufacturing method, in steps S11 and S12, a metal tube having a predetermined size is produced in the same manner as in steps S1 and S2 of the first manufacturing method described above, and the peripheral surface of the metal tube is formed into a predetermined shape. Thus, the processed cylindrical body 100 is produced. At this time, the material of the metal tube (metal material) is age-hardening material, and for example, precipitation hardened stainless steel such as SPRON and SUS630 which are one of cobalt base alloys is used.

  Thereafter, an aging process is performed on the processed cylindrical body 100 (step S13). Thereby, since a fine precipitate appears on the whole processing cylinder 100, the intensity of the whole processing cylinder 100 can be increased.

  Subsequently, in steps S14 to S16, the first and second laser irradiations are performed in each of the first to eighth annular bodies 102a to 102h, similarly to steps S3 to S5 of the first manufacturing method described above. I do. Thereby, the stent 18 which concerns on this embodiment is completed.

(Third production method)
Next, a third method for manufacturing the stent 18 according to the present embodiment will be described with reference to FIGS.

  In the third manufacturing method, steps S1 to S5 of the first manufacturing method described above are performed. However, the material of the metal tube (metal material) is the same as the material of the metal tube described in the second manufacturing method, and the laser conditions are different in step S3 and step S4.

  In this manufacturing method, in step S3, for example, when one end portion 108a of the first linear portion 108 is irradiated with the laser light L, the spot diameter d3 of the laser light L is the spot diameter in the first manufacturing method described above. For example, it is set to be equal to the width W1 of the end portion 108a (see FIG. 11A).

  Thereby, the heat of the laser beam L can be transmitted to the intermediate portion 108c of the first straight portion 108, so that one end portion 108a of the first straight portion 108 is annealed and one portion of the intermediate portion 108c is surely secured. Can be age-hardened.

  The first straight line is also applied when the other end 112b of the extending portion 112, the one end 116a of the second straight portion 116, and the other end 120b of the third straight portion 120 are irradiated with the laser light L. This is performed in the same manner as the laser irradiation method for one end portion 108a of the portion 108.

  Thus, the other end 112b of the extending portion 112, one end 116a of the second straight portion 116, and the other end 120b of the third straight portion 120 are annealed, and an intermediate portion 112c of the extending portion 112 is obtained. One part, one part of the intermediate part 116c of the second straight part 116, and one part of the intermediate part 120c of the third straight part 120 can be age-hardened reliably.

  For example, when the laser beam L is irradiated to the outer peripheral portion 110a of the first curved portion 110, the spot diameter d4 of the laser light L is larger than the spot diameter d2 in the first manufacturing method described above. It is set to the same size as the width of the part 110a (see FIG. 11B).

  Thereby, the heat of the laser beam L can be transmitted to the intermediate part 110c of the first curved part 110, so that the outer peripheral part 110a of the first curved part 110 is annealed and one part of the intermediate part 110c is reliably aged. It can be cured.

  Even when the laser beam L is applied to the inner peripheral portion 114b of the second music portion 114, the outer peripheral portion 118a of the third music portion 118, and the inner peripheral portion 122b of the fourth music portion 122, the first music portion 110 is also irradiated. This is performed in the same manner as the laser irradiation method for the outer peripheral portion 110a.

  As a result, the inner peripheral part 114b of the second music part 114, the outer peripheral part 118a of the third music part 118, and the inner peripheral part 122b of the fourth music part 122 are annealed, and the intermediate part 114c of the second music part 114 is obtained. One part, one part of the intermediate part 118c of the third music part 118, and one part of the intermediate part 122c of the fourth music part 122 can be age-hardened reliably.

  In step S4, the other end portion 108b of the first straight portion 108, one end portion 112a of the extending portion 112, the other end portion 116b of the second straight portion 116, and one end portion of the third straight portion 120. When irradiating the laser beam L to 120a, it carries out similarly to the laser irradiation method with respect to one edge part 108a of the 1st linear part 108. FIG.

  Further, the laser beam L is applied to the inner peripheral part 110 b of the first music part 110, the outer peripheral part 114 a of the second music part 114, the inner peripheral part 118 b of the third music part 118, and the outer peripheral part 122 a of the fourth music part 122. When irradiating, it carries out similarly to the laser irradiation method with respect to the outer peripheral part 110a of the 1st music part 110. FIG.

  Accordingly, the other end portion 108b of the first straight portion 108, the inner peripheral portion 110b of the first curved portion 110, the one end portion 112a of the extending portion 112, the outer peripheral portion 114a of the second curved portion 114, and the second straight portion. The other end portion 116 b of 116, the inner peripheral portion 118 b of the third curved portion 118, one end portion 120 a of the third straight portion 120, and the outer peripheral portion 122 a of the fourth curved portion 122 can be annealed.

  In addition, another part of the intermediate part 108c of the first straight part 108, another part of the intermediate part 110c of the first curved part 110, another part of the intermediate part 112c of the extending part 112, and an intermediate part of the second curved part 114 114c, other part of the intermediate part 116c of the second straight part 116, other part of the intermediate part 118c of the third curved part 118, other part of the intermediate part 120c of the third straight part 120, fourth part The other part of the intermediate part 122c of the curved part 122 can be age-hardened reliably. As a result, the stent 18 according to the present embodiment is completed.

  In this manufacturing method, the annealing and the aging treatment can be performed at the same time using the heat of the laser beam L, so that the cycle time can be shortened.

(Fourth manufacturing method)
Next, the 4th manufacturing method of the stent 18 which concerns on this Embodiment is demonstrated, referring FIG.12 and FIG.13.

  In the fourth manufacturing method, in steps S21 and S22 of FIG. 12, similarly to steps S1 and S2 of the first manufacturing method described above, a metal tube having a predetermined size is produced, and the peripheral surface of the metal tube is determined in advance. The processed cylindrical body 100 is manufactured by forming into a shape. At this time, the material of the metal tube (metal material) is a material having quench hardenability, and for example, carbon steel, alloy steel, martensitic stainless steel or the like is used.

  Next, an annealing process is performed on the processed cylindrical body 100 (step S23). Thereby, since the distortion of the processed cylinder 100 that has been work-hardened by the drawing process is removed, the processed cylinder 100 is softened.

  One end 108a of the first straight portion 108 is the end 44a, the other end 108b is the end 44b, the outer peripheral portion 110a of the first curved portion 110 is the outer peripheral portion 46a, and the inner peripheral portion 110b is One end 112a of the extending portion 112 is at the end 48a, the other end 112b is at the end 48b, the outer peripheral portion 114a of the second curved portion 114 is at the outer peripheral portion 50a, and the inner peripheral portion is at the inner peripheral portion 46b. 114b is the inner peripheral portion 50b, one end 116a of the second straight portion 116 is the end 52a, the other end 116b is the end 52b, and the outer peripheral portion 118a of the third curved portion 118 is the outer peripheral portion 54a. The inner peripheral part 118b is the inner peripheral part 54b, the one end part 120a of the third linear part 120 is the end part 56a, the other end part 120b is the end part 56b, and the outer peripheral part 122a of the fourth curved part 122 is In the outer peripheral part 58a, Site 122b is in the inner peripheral portion 58b.

  Subsequently, laser irradiation is performed on the first annular body 102a (step S24). In this step, as shown in FIG. 13, in each of the plurality of linear patterns 106 of the first annular body 102 a, the intermediate portion 108 c of the first straight portion 108, the intermediate portion 110 c of the first curved portion 110, and the extending portion 112. Intermediate part 112c, intermediate part 114c of second curved part 114, intermediate part 116c of second straight part 116, intermediate part 118c of third curved part 118, intermediate part 120c of third straight part 120, and fourth music The laser beam L is irradiated so as to pass through the intermediate part 122c of the part 122.

  For example, when the laser beam L is irradiated to the intermediate portion 108c of the first straight portion 108, the spot diameter d5 of the laser light L is set to approximately half the width W3 of the intermediate portion 108c, and the laser output is set to the intermediate portion 108c. The temperature is set so that the crystal structure can be martensitic transformed, and the robot is positioned so that the central axis of the laser beam L is located at the center (neutral plane) in the width direction of the intermediate portion 108c. The position of the processing cylinder 100 is controlled (see FIG. 14A).

  As a result, the heat of the laser beam L can be diffused throughout the intermediate portion 108c of the first straight portion 108, so that the crystal structure of the intermediate portion 108c can be set to a temperature at which martensitic transformation is possible. Further, when the intermediate portion 108c is heated by the laser light L, the heat is transmitted to the end portion 108a and the end portion 108b, so that the intermediate portion 108c is rapidly cooled. Thereby, the crystal structure of the intermediate portion 108c can be surely transformed into martensite.

  Even when the intermediate portion 112c of the extending portion 112, the intermediate portion 116c of the second straight portion 116, and the intermediate portion 120c of the third straight portion 120 are irradiated with the laser light L, the intermediate portion 108c of the first straight portion 108 is used. The same as the laser irradiation method for.

  Thereby, the crystal structure of the intermediate part 112c of the extending part 112, the intermediate part 116c of the second straight part 116, and the intermediate part 120c of the third straight part 120 can be reliably martensitic transformed.

  Further, for example, when the laser beam L is irradiated to the intermediate portion 110c of the first curved portion 110, the spot diameter d6 of the laser beam L is set to substantially half of the width W4 of the intermediate portion 110c, and the laser output is The temperature is set so that the crystal structure of the intermediate portion 110c can be martensitic transformed, and the robot has the center axis of the laser beam L positioned at the center (neutral plane) in the width direction of the intermediate portion 110c. Thus, the position of the machining cylinder 100 is controlled (see FIG. 14B).

  Thereby, the heat of the laser beam L can be diffused throughout the intermediate portion 110c of the first curved portion 110, so that the crystal structure of the entire intermediate portion 110c can be set to a temperature at which martensitic transformation is possible. Further, when the intermediate portion 110c is heated by the laser light L, the heat is transmitted to the outer peripheral portion 110a and the inner peripheral portion 110b, so that the intermediate portion 110c is rapidly cooled. Thereby, the crystal structure of the intermediate portion 110c can be surely martensitic transformed.

  It should be noted that the intermediate portion 114c of the second curved portion 114, the intermediate portion 118c of the third curved portion 118, and the intermediate portion 122c of the fourth curved portion 122 are also irradiated with the laser light L in the middle of the first curved portion 110. This is performed in the same manner as the laser irradiation method for the portion 110c.

  Thereby, the martensitic transformation of the intermediate part 114c of the 2nd music part 114, the intermediate part 118c of the 3rd music part 118, and the intermediate part 122c of the 4th music part 122 can be carried out reliably.

  As described above, when laser irradiation is performed on the first annular body 102a, the intermediate portion 108c of the first straight portion 108 extends to the intermediate portion 44c, and the intermediate portion 110c of the first curved portion 110 extends to the intermediate portion 46c. The intermediate part 112c of the part 112 is the intermediate part 48c, the intermediate part 114c of the second curved part 114 is the intermediate part 50c, the intermediate part 116c of the second straight part 116 is the intermediate part 52c, and the intermediate part of the third curved part 118 118c becomes the intermediate part 54c, the intermediate part 120c of the third straight part 120 becomes the intermediate part 56c, and the intermediate part 122c of the fourth curved part 122 becomes the intermediate part 58c.

  Thereafter, the laser irradiation described above is performed on each of the second to eighth annular bodies 102b to 102h (step S25). As a result, the stent 18 according to the present embodiment is completed.

  Next, the operation of the stent 18 according to the present embodiment configured as described above will be described.

  First, for example, the stent 18 manufactured by any one of the first to fourth manufacturing methods described above is contracted (plastically deformed) inward in the radial direction thereof, whereby the tube of the balloon 16 in a contracted state. Mounted on the portion 16b.

  And the form of the stenosis part (lesion part) which generate | occur | produced in the coronary artery etc. is specified by the intravascular contrast method or the intravascular ultrasonic diagnostic method.

  Next, the guide wire 20 is introduced into the blood vessel percutaneously from the thigh or the like by the Seldinger method, for example, and the guide wire 20 is inserted through the guide wire lumen from the distal end opening of the shaft 12. The stent system 10 is inserted into the blood vessel. At this time, the stent system 10 is inserted in a form in which the balloon 16 is contracted or folded.

  Then, under X-ray contrast, the guide wire 20 is advanced to the intended stenosis, and is passed through the stenosis, and the stent system 10 is advanced along the guide wire 20 into the coronary artery.

  As the stent system 10 advances, the balloon 16 of the stent system 10 reaches the stenosis. At this stage, the balloon 16 is expanded by pumping an expansion fluid (for example, a contrast medium) from the hub 14 side into the balloon lumen of the shaft 12.

  The expansion of the balloon 16 pushes the stenosis portion and expands the stent 18, and the stent 18 is closely attached and fixed to the inner wall of the stenosis portion.

  In the stent 18 according to the present embodiment, in each of the first to eighth annular bodies 22a to 22h, the strength of the intermediate portion 46c of the first curved portion 46 is greater than the strength of the outer peripheral portion 46a and the inner peripheral portion 46b. Therefore, the strength of the first curved portion 46 can be increased as compared with the case where the entire first curved portion 46 is set to the strength of the outer peripheral portion 46a or the inner peripheral portion 46b. Thereby, even if it is a case where the stent 18 is formed thinly, it can suppress that the 1st curved part 46 rises at the time of expansion, and can raise radial force. Further, since the strength of the intermediate portion 46c having a small distortion (deformation amount) during expansion is increased and the strength of the outer peripheral portion 46a and the inner peripheral portion 46b having a large strain (deformation amount) is reduced, the intermediate portion 46c Even within the elastic deformation region, the outer peripheral portion 46a and the inner peripheral portion 46b can be reliably plastically deformed. Thereby, recoil can be suppressed low.

  Further, in the stent 18 according to the present embodiment, in each of the first to eighth annular bodies 22a to 22h, the strength of the intermediate portion 50c of the second curved portion 50 is determined from the strength of the outer peripheral portion 50a and the inner peripheral portion 50b. The strength of the intermediate portion 54c of the third curved portion 54 is higher than the strength of the outer peripheral portion 54a and the inner peripheral portion 54b, and the strength of the intermediate portion 58c of the fourth curved portion 58 is higher than the outer peripheral portion 58a and the inner peripheral portion. Since it is set higher than the strength of 58b, the radial force can be further increased and the recoil can be further reduced.

  In the stent 18 according to the present embodiment, the strength of the intermediate portion 44c of the first straight portion 44 is higher than the strength of both end portions 44a and 44b, and the strength of the intermediate portion 48c of the extending portion 48 is set to both end portions 48a and 48b. The strength of the intermediate portion 52c of the second straight portion 52 is higher than the strength of its both end portions 52a and 52b, and the strength of the intermediate portion 56c of the third straight portion 56 is the strength of its both end portions 56a and 56b. Therefore, the radial force can be further increased and the recoil can be further reduced.

  The stent 18 according to the present embodiment is not limited to the configuration described above. For example, in the linear pattern 26, the strength of the intermediate portion 44c of the first straight portion 44 is set to be the same as the strength of the both end portions 44a, 44b, and the extending portion 48, the second straight portion 52, and the third straight line. The strength of the portion 56 may be set similarly to the strength of the first straight portion 44. That is, in the linear pattern 26, at least one of the first to third straight portions 44, 52, 56 and the extending portion 48 may be set to the above-described strength.

  The stent 18 according to the present embodiment has, for example, a metal wire 42 near the boundary between the first curved portion 46 and the first straight portion 44 and / or near the boundary between the first curved portion 46 and the extending portion 48. A high-strength portion having the same strength as that of the intermediate portion 46c of the first curved portion 46 may be formed over the entire width. Thereby, the radial force of the stent 18 can be further increased.

  The high-strength portion is in the vicinity of the boundary between the second curved portion 50 and the extending portion 48, in the vicinity of the boundary between the second curved portion 50 and the second straight portion 52, and in the third curved portion 54 and the second straight portion 52. In the vicinity of the boundary between the third curved portion 54 and the third straight portion 56, in the vicinity of the fourth curved portion 58 and the third straight portion 56, and / or in the fourth curved portion 58. It may be provided in the vicinity of the boundary portion of the first straight portion 44. The high-strength portion can be arbitrarily provided depending on the design and characteristics of the stent.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various configurations and manufacturing methods can be adopted without departing from the gist of the present invention.

  The stent according to the present invention only needs to have a curved portion, for example, a predetermined metal wire formed into a mesh shape and formed into a cylindrical shape, or a metal wire wound in a spiral shape into a cylindrical shape It may be a thing.

DESCRIPTION OF SYMBOLS 10 ... Stent system 12 ... Shaft 14 ... Hub 16 ... Balloon 18 ... Stent 22a ... 1st annular body 22b ... 2nd annular body 22c ... 3rd annular body 22d ... 4th annular body 22e ... 5th annular body 22f ... 6th Ring body 22g ... Seventh ring body 22h ... Eighth ring body 24 ... Connection part 26-40 ... Linear pattern 42 ... Metal wire (linear part)
44 ... first straight portion 44a ... one end 44b ... the other end 44c ... intermediate portion 46 ... first curved portion 46a ... outer peripheral portion 46b ... inner peripheral portion 46c ... intermediate portion 100 ... machined cylindrical body (cylindrical body) L ... Laser light

Claims (12)

A stent formed of a cylindrical body having a linear portion having a curved portion, and expandable radially outward of the cylindrical body,
In the curved portion, the strength of the intermediate part located between the outer peripheral part and the inner peripheral part is set higher than the strength of the outer peripheral part and the inner peripheral part, and the outer peripheral part, the inner peripheral part and the intermediate part Are integrally formed of the same metal . The stent of claim 1,
The linear portion has a straight portion,
The linear portion is characterized in that the strength of the intermediate portion located between the extending direction and both ends in the direction orthogonal to the radial direction of the cylindrical body is set higher than the strength of the both ends. Stent. The stent according to claim 1 or 2,
The cylindrical body is formed by connecting a plurality of annular bodies having a plurality of the curved portions in the axial direction. A tubular shaft,
An expandable balloon provided on the shaft;
A stent system comprising a stent mounted on the balloon,
The stent system according to any one of claims 1 to 3, wherein the stent is a stent system. A stent manufacturing method for manufacturing a stent expandable radially outward by altering a metal cylindrical body having a linear portion having a curved portion,
A first annealing step for annealing the outer peripheral portion of the curved portion;
And performing a second annealing step of annealing an inner peripheral portion located so as to sandwich the intermediate portion between the curved portion and the outer peripheral portion , thereby increasing the strength of the intermediate portion and the outer peripheral portion and the inner peripheral portion. The stent manufacturing method characterized by making it higher than intensity | strength . The stent manufacturing method according to claim 5,
The cylindrical body has age-hardening properties,
An aging treatment is performed on the cylindrical body before the first annealing step. The stent manufacturing method according to claim 5,
The cylindrical body has age-hardening properties,
In the first annealing step, one part of the intermediate part is age-hardened by heat generated when the outer peripheral part is annealed,
In the second annealing step, the other part of the intermediate part is age-hardened by heat generated when the inner peripheral part is annealed. In the stent manufacturing method according to any one of claims 5 to 7,
The linear part has a straight part,
A third annealing step of annealing one end of the linear portion in the direction orthogonal to the extending direction and the radial direction of the cylindrical body;
A stent manufacturing method comprising: performing a fourth annealing step of annealing the other end of the linear portion in a direction orthogonal to the extending direction and the radial direction of the cylindrical body. The stent manufacturing method according to claim 8,
The said 1st-4th annealing process anneals using a laser beam, The stent manufacturing method characterized by the above-mentioned. A stent manufacturing method for manufacturing a stent expandable radially outward by altering a metal cylindrical body having a linear portion having a curved portion,
The cylindrical body has quench hardenability,
An annealing step for annealing the cylindrical body;
By heating an intermediate part located between the outer peripheral part and the inner peripheral part of the curved portion, the crystal structure of the intermediate part is transformed into a martensite , and the strength of the intermediate part is increased between the outer peripheral part and the inner peripheral part. A stent manufacturing method characterized by being higher than strength . The stent manufacturing method according to claim 10, wherein
The linear part has a straight part,
After the annealing step, by heating an intermediate portion located between both ends of the linear portion in a direction orthogonal to the extending direction and the radial direction of the cylindrical body, the crystal structure of the intermediate portion is changed. A stent manufacturing method comprising martensitic transformation. The stent manufacturing method according to claim 11,
The stent manufacturing method according to claim 1, wherein heating of the intermediate portion of the curved portion and the intermediate portion of the straight portion is performed using laser light.

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