In-vivo indwelling stent and stent delivery system

Abstract

An in-vivo indwelling stent 1 is self-expanding and comprises: annular bodies 2 provided with a plurality of bent parts 21, 22 having apexes on one end side and the other end side; and connection parts 31, 32 connecting the annular bodies 2. The apexes of adjacent bent parts 21, 22 are shifted by a predetermined length in the circumferential direction of a stent body. The connection parts are provided, alternately in the axial direction, with first pattern connection parts 31 extending obliquely at a predetermined angle with respect to the central axis of the stent body, and second pattern connection parts 32 extending in a direction different from the first pattern connection parts 31.

Description

Intravascular stent and stent delivery system

[0001] The present invention relates to an intravascular stent used for treating stenotic or occluded portions formed in the lumen of blood vessels, bile ducts, trachea, esophagus, urethra, and other organs. In particular, it relates to a self-expanding type intravascular stent.

[0002] There are cases of formation of stenotic portions due to calcification in blood vessels, particularly in the lower limb arteries. In order to improve the stenotic portion due to calcification in the lower limb arteries, for example, in the superficial femoral artery (SFA), it is desirable for the stent to have a high expansion force that can expand even in calcified lesions and flexibility that can withstand loads such as bending and torsion caused by external forces on the superficial femoral artery. As an intravascular stent, there is one that includes a plurality of annular bodies capable of deforming in a direction in which the outer diameter shrinks when a stress load is applied, and a connecting portion that connects the plurality of annular bodies in a state arranged in the axial direction of the stent body. As such a type of stent, the applicant of the present application has proposed JP-A-2005-279076 (Patent Document 1). The self-expanding intravascular stent 1 of Patent Document 1 includes a plurality of annular bodies 2 and a connecting portion ③ that connects the plurality of annular bodies 2 in a state arranged in the axial direction of the stent. The annular body 2 has a large number of strut portions 21 that are substantially parallel to the central axis of the stent when the stent is reduced in diameter, and loop portions 22 that connect adjacent strut portions. The connecting portion 3 is curved in a substantially arc shape, and the width (E) of the connecting portion 3 is wider than the width (F) of the strut portion 21.

[0003] JP-A-2005-279076

[0004] In the self-expanding intravascular stent of Patent Document 1, during intravascular implantation, the zigzag-shaped wavy annular body maintains an appropriate shape and is less likely to cause concentration of strain on the connecting portion. However, in order to improve the stenotic portion due to calcification in the lower limb arteries, it is desirable for the stent to have a high expansion force that can expand even in calcified lesions and flexibility that can withstand loads such as bending and torsion caused by external forces on the superficial femoral artery.

[0005] The object of the present invention is to provide a self-expanding in vivo stent that exhibits good expansion force even in calcified lesions when placed in a narrowed area due to calcification in a lower limb artery, and that has the flexibility to withstand bending, twisting, and other loads caused by external forces on the superficial femoral artery.

[0006] The following is a stent for implantation in a biological system that achieves the above objective: A self-expanding in-vivo stent formed in a cylindrical shape, which can be reduced in diameter by compression in the direction of the central axis and restored to its original shape by releasing the compression, wherein the in-vivo stent comprises a stent body, the stent body comprises a plurality of annular bodies that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the plurality of annular bodies in a state in which the annular bodies are arranged in the axial direction of the stent body, The annular body is formed of a wavy linear component having a plurality of bent portions with vertices on one end and the other end in the axial direction, and between adjacent annular bodies in the axial direction of the in vivo stent, the vertices of the adjacent bent portions are offset by a predetermined length in the circumferential direction of the stent body, and the connection portion comprises a first pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body and in a direction different from the first pattern connection portion, and the connection portion between opposing annular bodies is either the first pattern connection portion or the second pattern connection portion, and the connection portions adjacent to the stent body in the axial direction are arranged such that the first pattern connection portion and the second pattern connection portion alternate.

[0007] Furthermore, the following is a device that achieves the above objective: A self-expanding in vivo stent formed in a cylindrical shape, which is reduced in diameter when inserted into a body and can be restored to its original shape when placed in a body, wherein the in vivo stent comprises a stent body, the stent body comprises a plurality of annular bodies that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the plurality of annular bodies in a state in which the annular bodies are arranged in the axial direction of the stent body, The annular body is formed of a wavy linear component having a plurality of bent portions with vertices on one end and the other end in the axial direction, and between adjacent annular bodies in the axial direction of the in vivo implantable stent, the vertices of the adjacent bent portions are offset by a predetermined length in the circumferential direction of the stent body, and the connection portion comprises a first pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body and in a direction different from the first pattern connection portion, and the connection portion between opposing annular bodies is either the first pattern connection portion or the second pattern connection portion, and the connection portions adjacent to each other in the axial direction of the stent body are arranged so that the first pattern connection portion and the second pattern connection portion alternate. Furthermore, the stent body comprises two maximum connection portion holders having connection portions between all adjacent vertices of the annular bodies at both ends of the stent body, two first reduced connection portion holders having 40 to 60% of the number of connection portions in the maximum connection portion holders between the annular bodies having the maximum connection portion holders and the annular bodies located axially inward of the stent body, and a second reduced connection portion holder having 40 to 60% of the number of connection portions in the first reduced connection portion holders between a plurality of annular bodies located between the two first reduced connection portion holders, wherein the space between the annular bodies has a second reduced connection portion holder having 40 to 60% of the number of connection portions in the first reduced connection portion holders.

[0008] Furthermore, the following is a device that achieves the above objective: a stent delivery system comprising a sheath, the above-mentioned in vivo implantable stent housed within the tip of the sheath, and an inner tube slidably inserted through the sheath for pushing the in vivo implantable stent out from the tip of the sheath.

[0009] The self-expanding in vivo stent of the present invention is formed in a cylindrical shape, and is a self-expanding in vivo stent that can be reduced in diameter by compression in the direction of the central axis and restored to its original shape by releasing the compression. The in vivo stent comprises a stent body, which comprises a plurality of annular bodies that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the annular bodies when the plurality of annular bodies are arranged in the axial direction of the stent body. The annular body is formed from a wavy linear component having multiple bent sections with vertices at one end and the other end in the axial direction. Between adjacent annular bodies in the axial direction of the in vivo implantable stent, the vertices of the adjacent bent sections are offset by a predetermined length in the circumferential direction of the stent body. The connection section comprises a first pattern connection section extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection section extending at a predetermined angle oblique to the central axis of the stent body and in a different direction from the first pattern connection section. The connection section between opposing annular bodies is either the first pattern connection section or the second pattern connection section, and is the same pattern connection section. The connection sections adjacent to each other in the axial direction of the stent body are arranged so that the first pattern connection section and the second pattern connection section alternate. Therefore, even when implanted in a stenotic area due to calcification in the lower limb artery, it exhibits good expansion force even in the calcified lesion and has the flexibility to withstand bending, twisting, and other loads caused by external forces on the superficial femoral artery.

[0010] Figure 1 is an unfolded view of a self-expanding in vivo stent according to an embodiment of the present invention. Figure 2 is an unfolded view of the in vivo stent shown in Figure 1 in a reduced diameter state. Figure 3 is a partially enlarged view of the in vivo stent shown in Figure 1. Figure 4 is an unfolded view of a self-expanding in vivo stent according to another embodiment of the present invention. Figure 5 is an unfolded view of a self-expanding in vivo stent according to another embodiment of the present invention. Figure 6 is a partially omitted front view of a stent delivery system according to an embodiment of the present invention. Figure 7 is an enlarged longitudinal cross-sectional view of the area near the tip of the stent delivery system shown in Figure 6. Figure 8 is a partially omitted enlarged cross-sectional view of the area near the proximal end of the stent delivery system shown in Figure 6. Figure 9 is an explanatory diagram for explaining the operation of a stent delivery system according to an embodiment of the present invention. Figure 10 is an unfolded view of a self-expanding in vivo stent according to another embodiment of the present invention. Figure 11 is an unfolded view of a self-expanding in vivo stent according to another embodiment of the present invention.

[0011] The in vivo stent of the present invention will be described using the embodiment shown in the drawings. The in vivo stent 1 of the present invention is a self-expanding in vivo stent 1 that is formed in a cylindrical shape, can be reduced in diameter by compression in the direction of the central axis, and can be restored to its original shape by releasing the compression. The in vivo stent comprises a stent body 10, the stent body 10 comprises a plurality of annular bodies 2 that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts 31, 32 that connect the annular bodies when the plurality of annular bodies 2 are arranged in the axial direction of the stent body.

[0012] The annular body 2 is formed from a wavy linear component having a plurality of bent portions 21, 22 with vertices on one end and the other end in the axial direction. Between annular bodies 2 adjacent to each other in the axial direction of the in vivo implantable stent, the vertices of the adjacent bent portions 21, 22 are offset by a predetermined length in the circumferential direction of the stent body. Furthermore, the connecting portions 31, 32 include a first pattern connecting portion 31 that extends at a predetermined angle oblique to the central axis of the stent body, and a second pattern connecting portion 32 that extends at a predetermined angle oblique to the central axis of the stent body and in a different direction from the first pattern connecting portion 31. The connecting portion between opposing annular bodies 2 is either the first pattern connecting portion 31 or the second pattern connecting portion 32, and is the same pattern connecting portion. The connecting portions adjacent to each other in the axial direction of the stent body are arranged so that the first pattern connecting portion 31 and the second pattern connecting portion 32 alternate.

[0013] Furthermore, in the in vivo stent 1 of the present invention, the stent body 10 further comprises two maximum connection portion holders 11 having connection portions between all adjacent vertices of adjacent annular bodies 2 at both ends of the stent body, two first reduced connection portion holders 12 having 40 to 60% of the number of connection portions in the maximum connection portion holder between the annular body 2 having the maximum connection portion holder and annular body 2 located axially inward of the stent body, and a second reduced connection portion holder 13 having 40 to 60% of the number of connection portions in the first reduced connection portion holder between a plurality of annular bodies 2 located between the two first reduced connection portion holders. The in vivo stent of the present invention is particularly effective as a stent for lower limb arteries.

[0014] The self-expanding in vivo stent 1 of this embodiment is formed in a substantially cylindrical shape and comprises a stent body 10 that is reduced in diameter when inserted into a body and can be restored to its original shape before reduction when implanted in a body, and a drug-containing coating portion provided on its outer surface. As shown in Figures 1 and 2, the stent body 10 comprises a plurality of annular bodies 2 that can deform in a direction in which the outer diameter is reduced when stress is applied, and connecting portions 31 and 32 that connect the plurality of annular bodies 2 in an axial position of the stent.

[0015] The annular body 2, when the stent is reduced in diameter, has a number of struts 23, 24 that are substantially parallel to the central axis of the stent, as shown in Figure 2, and bent portions 21, 22 that connect adjacent struts 23, 24. The number of bent portions 21 on one end and bent portions 22 on the other end of the annular body 2 of the stent body 10, and the number of peaks on one end and valleys on the other end of the annular body 2, are preferably 12 to 20, and particularly preferably 16.

[0016] The connecting portions 31 and 32 extend diagonally with respect to the central axis of the stent body 10, and the connecting portions 31 and 32 are generally straight, with the widths (line widths) of the connecting portions 31 and 32, the struts 23 and 24, and the bent portions being approximately the same. The widths (line widths) of the connecting portions 31 and 32, the struts 23 and 24, and the bent portions are preferably 0.08 mm to 0.120 mm, and particularly preferably 0.10 mm to 0.115 mm.

[0017] Furthermore, the annular body 2 is formed from a wavy linear component having a plurality of bent portions 21, 22 with vertices on one end and the other end in the axial direction. Between annular bodies 2 adjacent to each other in the axial direction of an in vivo implantable stent, the vertices of the adjacent bent portions 21, 22 are offset by a predetermined length (specifically, about 0.040 to 0.042 mm) in the circumferential direction of the stent body.

[0018] Furthermore, the connecting portions 31 and 32 include a first pattern connecting portion 31 that extends at a predetermined angle oblique to the central axis of the stent body, and a second pattern connecting portion 32 that extends at a predetermined angle oblique to the central axis of the stent body and in a direction different from that of the first pattern connecting portion 31. The connecting portion between two opposing annular bodies 2 is either the first pattern connecting portion 31 or the second pattern connecting portion 32, and is the same pattern connecting portion. The connecting portions adjacent in the axial direction of the stent body are arranged so that the first pattern connecting portion 31 and the second pattern connecting portion 32 alternate.

[0019] In particular, in the in vivo stent 1 of this embodiment, as shown in Figures 1 and 2, the group of connection parts 15a located at one end (between the annular body at one end and the adjacent annular body) are all composed of a first pattern connection part 31 that extends diagonally downward to the left (on the drawing) at a predetermined angle with respect to the central axis of the stent body. The group of connection parts 16a adjacent to the group of connection parts 15a in the axial direction of the stent body 10 are all composed of a second pattern connection part 32 that extends diagonally downward to the right (on the drawing) at a predetermined angle with respect to the central axis of the stent body.

[0020] Furthermore, all connection group 17a adjacent to connection group 16a in the axial direction of the stent body 10 are composed of a first pattern connection part 31 that extends diagonally downward and to the left (in the drawing) at a predetermined angle with respect to the central axis of the stent body. Similarly, all connection group 17b adjacent to connection group 17a in the axial direction of the stent body 10 are composed of a second pattern connection part 32 that extends diagonally downward and to the right (in the drawing) at a predetermined angle with respect to the central axis of the stent body. Thereafter, connection group 17a composed of the first pattern connection part 31 and connection group 17b composed of the second pattern connection part 32 are arranged alternately in the axial direction.

[0021] Furthermore, as shown in Figures 1 and 2, the connection portion 31 and the connection portion 32 are not continuous in the axial direction of the stent body 10 between the connection portion group 17a and the connection portion group 17b. Specifically, the connection portion 32 of the connection portion group 17b is not located in the direction of the other end of the axis of the connection portion 31 of the connection portion group 17a, in other words, downward (on the drawing), and the other end bent portion 22, which is a free end, is located below the connection portion 31 (on the drawing). Similarly, the connection portion 31 of the connection portion group 17a is not located in the direction of the other end of the axis of the connection portion 32 of the connection portion group 17b, in other words, downward (on the drawing), and the other end bent portion 22, which is a free end, is located below the connection portion 32 (on the drawing).

[0022] Furthermore, the group of connection parts 15b located at the other end (between the annular body at the other end and the adjacent annular body) are all composed of a second pattern connection part 32 that extends diagonally downward to the right at a predetermined angle with respect to the central axis of the stent body (in the drawing). Furthermore, the group of connection parts 16b adjacent to the group of connection parts 15b in the axial direction of the stent body 10 are all composed of a first pattern connection part 31 that extends diagonally downward to the left at a predetermined angle with respect to the central axis of the stent body (in the drawing).

[0023] Furthermore, in the in vivo implantable stent 1 of this embodiment, the stent body 10 has two maximum connection portion holders 11a, 11b that have connection portions between all adjacent vertices of adjacent annular bodies 2 at both ends of the stent body, two first diminished connection portion holders 12a, 12b that have 40 to 60% of the number of connection portions in the maximum connection portion holders between the annular bodies 2 having the maximum connection portion holders 11a, 11b and the annular bodies 2 located axially inward of the stent body, and second diminished connection portion holders 13a, 13b that have 40 to 60% of the number of connection portions in the first diminished connection portion holders between a plurality of annular bodies 2 located between the two first diminished connection portion holders 12a, 12b. Furthermore, it is preferable that the second reduction connection holder has 45 to 55% of the number of connection parts in the first reduction connection holder.

[0024] Specifically, as shown in Figures 1 and 2, one end (between the annular body at one end and the adjacent annular body) has a maximum connection portion 11a that connects all of the diagonally opposing bent portions 22 on the other end and the bent portion 21 on the one end. Therefore, the annular bodies 2 at one end do not have any bent portions 21 and 22 that become free ends. Furthermore, all the connection portions between the annular body at one end and the adjacent annular body, in other words, the connection portions in the maximum connection portion 11a, are first pattern connection portions 31 that extend diagonally downward to the left (in the drawing) at a predetermined angle with respect to the central axis of the stent body.

[0025] Furthermore, the stent body 10 has a maximum connection portion 11b at the other end (between the annular body at the other end and the adjacent annular body) that connects all of the diagonally opposing bent portions 22 on the other end side and the bent portion 21 on the one end side. For this reason, there are no free-end bent portions 21 and 22 between the annular bodies 2 at the other end. The connection portions between the annular body at the other end and the adjacent annular body, in other words, the connection portions in the maximum connection portion 11b, are all second pattern connection portions 32 that extend diagonally downward to the right at a predetermined angle with respect to the central axis of the stent body (in the drawing).

[0026] Furthermore, the space between the annular body 2 having the most connection portion 11a at one end and the annular body 2 located axially inward from the stent body is a first reduced number of connection portion 12a, which has 40 to 60% of the number of connection portions in the most connection portion 11a. In the examples shown in Figures 1 and 2, the number of connection portions in the most connection portion 11a is 16, and the number of connection portions in the first reduced number of connection portion 12a is 8, which is 50% of the number of connection portions in the most connection portion 11a. The connection portions in the first reduced number of connection portion 12a are arranged at equiangled angles with respect to the central axis of the stent body 10.

[0027] Similarly, the space between the annular body 2 having the most connection portion 11b at the other end and the annular body 2 located axially inward from the stent body is a first reduced number of connection portion 12b, which has 40-60% of the number of connection portions in the most connection portion 11b. In Figures 1 and 2, the number of connection portions in the most connection portion 11b is 16, and the number of connection portions in the first reduced number of connection portion 12b is 8, which is 50% of the number of connection portions in the most connection portion 11b. The connection portions in the first reduced number of connection portion 12b are arranged at equiangled angles with respect to the central axis of the stent body 10.

[0028] Furthermore, the space between the annular body 2 located between the first diminishing connection holders 12a and 12b is a second diminishing connection holder 13a and 13b, having 40 to 60% of the number of connection parts in the first diminishing connection holder. In the configuration shown in Figures 1 and 2, the number of connection parts in the first diminishing connection holders 12a and 12b is 8, and the number of connection parts in the second diminishing connection holders 13a and 13b is 4, which is 50% of the number of connection parts in the first diminishing connection holders 12a and 12b. The connection parts in the second diminishing connection holders 13a and 13b are arranged at equal angles with respect to the central axis of the stent body 10. The axial length of the annular body 2 during self-expansion is preferably 1.3 to 1.7 mm, particularly preferably 1.4 to 1.6 mm, and even more preferably 1.45 to 1.55 mm. The lengths of the connecting portions 31 and 32 are preferably 0.35 to 0.50 mm, and more preferably 0.40 to 0.45 mm. The total axial length of one annular body and the connecting portions connected thereto is preferably 1.5 to 2.5 mm, and more preferably 2.0 to 2.2 mm.

[0029] Furthermore, the inclination angles of the connection portions 31 and 32 with respect to the central axis of the stent body during the self-expansion of the annular body 2 (the inclination angles with respect to the central axis of the stent body in the deployed state of the stent, A1 and A2 in Figure 3) are preferably 110 to 130 degrees, and particularly preferably 115 to 125 degrees. It is preferable that the inclination angle A1 at connection portion 31 and the inclination angle A2 at connection portion 32 shown in Figure 3 are approximately the same (specifically, the difference is less than 5%).

[0030] In this embodiment, the stent body 10 has an outer diameter of 4.0 to 10.0 mm during self-expansion, and is particularly preferably 5.0 to 9.0 mm. The axial length of the stent during self-expansion is preferably 30 to 200 mm, particularly preferably 40 to 180 mm, and more preferably 40 to 150 mm. The number of annular bodies 2 in the stent body 10 is preferably 7 to 100, and more preferably 20 to 90.

[0031] In the in vivo stent 1 of the present invention, the ratio of the outer surface area of ​​the stent body 10 to the outer surface area of ​​the virtual cylindrical body of the in vivo stent 1 during self-expansion is preferably 15% to 20%, and particularly preferably 15% to 18%. The virtual cylindrical body of the in vivo stent 1 refers to the cylindrical body formed by the outer diameter and total length of the stent body 10 during self-expansion. Furthermore, the ratio of the outer surface area of ​​the stent body 10 to the outer surface area of ​​the virtual cylindrical body can be calculated as "total outer surface area of ​​the stent body 10 / outer surface area of ​​the virtual cylindrical body (outer surface area of ​​the cylindrical body formed by the outer diameter and total length of the stent body 10 during self-expansion)".

[0032] As shown in Figure 3, the in vivo stent has multiple lateral openings formed within adjacent annular bodies 2 during self-expansion. As shown in Figure 3, the multiple lateral openings formed within adjacent annular bodies 2 during self-expansion are formed by struts 23, struts 24, bent portions 21, 22, and connecting portions 31, 32. The radius (C) of the maximum inscribed circle (B) at each lateral opening is preferably 0.37 to 0.45 mm, and particularly preferably 0.37 to 0.40 mm. The size of the lateral openings is not uniform and varies depending on the location. Also, the radius (C) of the maximum inscribed circle (B) at each lateral opening does not vary greatly, but they are not all the same. It is preferable that the radius (C) of the maximum inscribed circle (B) at each lateral opening is approximately the same (specifically, the difference is less than 15%, preferably less than 10%).

[0033] Furthermore, it is preferable that the diameter retention rate at the center of the in-vivo stent 1, when the central part of the in-vivo stent is curved with a radius of curvature of R7.5 mm, is 85% or more, and particularly preferably 87% or more. The diameter retention rate at the center of the in-vivo stent when the central part of the in-vivo stent is curved with a radius of curvature of R7.5 mm is calculated by pressing the central part of the in-vivo stent against a cylindrical rod with a radius of curvature of R7.5 mm and pressing down on both sides of the in-vivo stent so that the in-vivo stent is aligned with the cylindrical rod with a radius of curvature of R7.5 mm. In this state, the central part of the in-vivo stent deforms into an elliptical cross-section and has a short-diameter portion. The diameter retention rate (%) is calculated by "length of the short-diameter portion of the central part when deformed / outer diameter of the in-vivo stent when not deformed" × 100.

[0034] Furthermore, the expansion force of the in vivo stent is preferably 9 to 11 N / cm. This expansion force can be measured using a commercially available radial force measuring device.

[0035] Furthermore, as in the stent 1 of this embodiment, it is preferable to provide markers 5 made of radiopaque material. It is preferable to provide the radiopaque material markers 5 at both ends of the stent body 10. In particular, as shown in Figures 1 and 2, it is preferable to provide multiple radiopaque material markers 5 at each end. The radiopaque material markers 5 are fixed to the stent so as to close the small opening formed in the stent. Such markers are preferably attached, for example, by placing a disc-shaped member of an X-ray contrast material having a portion slightly smaller and a portion larger than the small opening formed in the stent body 10, pressing it from both sides, and crimping it in a rivet-like manner.

[0036] The material used to form the stent body 10 is preferably a metal having superelastic properties. Specific examples of alloys having superelastic properties include Ni-Ti alloys (which may also contain Co, Fe, Zr, Hf, Pd, Au, Fe, Pt, and Mo), Cu alloys (which may also contain Al, Mn, Ni, and Zn), and Mg alloys (which may also contain Li, Al, Zn, Ca, Y, W, Zr, Gd, Mn, Sc, Cu, Ag, Nd, and other rare earth metals).

[0037] Furthermore, the in vivo stent 1 preferably includes a drug-containing coating portion provided on the outer surface of the stent body. The drug-containing coating portion is preferably provided on the entire outer surface of the stent body, including the bent portions 21, 22 and the connecting portions 31, 32. The drug-containing coating portion preferably contains sirolimus or a sirolimus derivative as the drug.

[0038] The drug coating the outer surface of the stent body may be supported on a polymer to form a drug-containing coating. When the drug-containing coating is supported on a polymer, the drug is gradually released after the stent is placed in the body, so the drug effect lasts for a long period of time and restenosis at the stent site is reliably prevented. Furthermore, since residual polymer may cause an inflammatory reaction, it is preferable that the polymer be a biodegradable polymer.

[0039] When the drug-containing coating is supported on a polymer, it is formed by applying a coating solution, prepared by dissolving the drug and polymer in a solvent, to the stent body.

[0040] The drug contained in the drug-containing coating of the in vivo implantable stent 1 is, for example, at least one compound selected from the group consisting of anticancer agents, immunosuppressants (e.g., sirolimus, sirolimus derivatives), antibiotics, antirheumatic agents, antithrombotic agents, HMG-CoA reductase inhibitors, ACE inhibitors, calcium channel blockers, antihyperlipidemic agents, integrin inhibitors, antiallergic agents, antioxidants, GPIIbIIIa antagonists, retinoids, flavonoids, carotenoids, lipid-improving agents, DNA synthesis inhibitors, tyrosine kinase inhibitors, antiplatelet agents, anti-inflammatory agents, bio-derived materials, interferon, and NO production-promoting substances.

[0041] The drug contained in the drug-containing coating of the in vivo implantable stent 1 is preferably sirolimus or a sirolimus derivative. Examples of sirolimus derivatives include everolimus, temsirolimus, ridafololimus, and zotalolimus. The biodegradable polymer is, for example, at least one polymer selected from the group consisting of polyester, aliphatic polyester, polyacid anhydride, polyorthoester, polycarbonate, polyphosphazene, polyphosphate ester, polyvinyl alcohol, polypeptide, polysaccharide, protein, and cellulose; a copolymer obtained by arbitrarily copolymerizing the monomers constituting the polymer; and a mixture of the polymer and / or the copolymer. Examples of aliphatic polyester are polylactic acid (PLA), polyglycolic acid (PGA), lactic acid-glycolic acid copolymer (PLGA), polycaprolactone (PCL), and a copolymer of lactic acid and caprolactone. Here, a copolymer of lactic acid and caprolactone is preferred.

[0042] Furthermore, a primer coating layer may be placed between the stent body and the drug-containing coating to reduce variations in the ease of peeling of the drug-containing coating on the stent body. As the material for the primer coating layer, for example, a biodegradable polymer material can be used when the drug-containing coating is supported on a polymer.

[0043] The present invention may also provide an in vivo stent 1a having an unfolded view during self-expansion as shown in Figure 4. The main differences between the in vivo stent 1a and the in vivo stent 1 described above are the number of bent portions 21 at one end and bent portions 22 at the other end of the annular body 2a of the stent body 10a, and the number of vertices at one end and the other end of the annular body 2a.

[0044] In the intravascular stent 1a, the number of one - end - side bent portions 21 and the number of the other - end - side bent portions 22 in the annular body 2a, and the number of the vertices on one - end - side and the other - end - side in the annular body 2a are 20. And in the intravascular stent 1a, as shown in FIG. 4, the number of connection portions in the maximum - connection - portion holding portions 11a, 11b is 20, the number of connection portions in the first - reduction - connection - portion holding portions 12a, 12b is 10, which is 50% of the number of connection portions in the maximum - connection - portion holding portion 11a. Also, the number of connection portions in the first - reduction - connection - portion holding portions 12a, 12b is 10, the number of connection portions in the second - reduction - connection - portion holding portions 13a, 13b is 5, which is 50% of the number of connection portions in the first - reduction - connection - portion holding portions 12a, 12b.

[0045] Also, as the intravascular stent of the present invention, an intravascular stent 1b having a deployment diagram at the time of self - expansion as shown in FIG. 5 may be used. The main difference between the intravascular stent 1b and the above - described intravascular stent 1 is the number of one - end - side bent portions 21 and the number of the other - end - side bent portions 22 in the annular body 2b of the stent body 10b, and the number of the vertices on one - end - side and the other - end - side in the annular body 2b.

[0046] In the intravascular stent 1b, the number of one - end - side bent portions 21 and the number of the other - end - side bent portions 22 in the annular body 2b, and the number of the vertices on one - end - side and the other - end - side in the annular body 2b are 12. And in the intravascular stent 1b, as shown in FIG. 5, the number of connection portions in the maximum - connection - portion holding portions 11a, 11b is 12, the number of connection portions in the first - reduction - connection - portion holding portions 12a, 12b is 6, which is 50% of the number of connection portions in the maximum - connection - portion holding portion 11a. Also, the number of connection portions in the first - reduction - connection - portion holding portions 12a, 12b is 6, the number of connection portions in the second - reduction - connection - portion holding portions 13a, 13b is 3, which is 50% of the number of connection portions in the first - reduction - connection - portion holding portions 12a, 12b.

[0047] In addition, the intravascular stent of the present invention may be an intravascular stent 1c having a deployment diagram during self-expansion as shown in FIG. 10. The main differences between the intravascular stent 1c and the above-described intravascular stent 1 are the number of annular bodies 2 in the stent body 10c and the total length of the stent body 10c resulting therefrom. In the intravascular stent 1c, the number of annular bodies 2 is 21. The axial lengths of each annular body and the connecting portion, and the diameter of each annular body are the same as those of the intravascular stent 1.

[0048] Also, in the intravascular stent 1c of this embodiment, one maximum connection portion holding portion 11a, 11b and first reduction connection portion holding portions 12a, 12b are provided at both ends of the stent body 10c, respectively. And between the two first reduction connection portion holding portions 12a, 12b, many second reduction connection portion holding portions 13a, 13b are provided. Therefore, the number of the second reduction connection portion holding portions 13a, 13b is significantly different between the intravascular stent 1c and the above-described intravascular stent 1.

[0049] In addition, the intravascular stent of the present invention may be an intravascular stent 1d having a deployment diagram during self-expansion as shown in FIG. 11. The main differences between the intravascular stent 1d and the above-described intravascular stent 1 are the number of annular bodies 2 in the stent body 10d and the total length of the stent body 10d resulting therefrom. In the intravascular stent 1d, the number of annular bodies 2 is 49. The axial lengths of each annular body and the connecting portion, and the diameter of each annular body are the same as those of the intravascular stent 1. Also, in the intravascular stent 1d of this embodiment, one maximum connection portion holding portion 11a, 11b and first reduction connection portion holding portions 12a, 12b are provided at both ends of the stent body 10d, respectively. And between the two first reduction connection portion holding portions 12a, 12b, many second reduction connection portion holding portions 13a, 13b are provided. Therefore, the number of the second reduction connection portion holding portions 13a, 13b is significantly different between the intravascular stent 1d and the above-described intravascular stent 1.

[0050] Next, the stent delivery system 50 of the present invention will be described with reference to Figures 6 to 9. The stent delivery system 50 of the present invention comprises a sheath 52, a stent 1 for implantation in a living body housed in the tip of the sheath 52, and an inner tube 54 that is slidably inserted inside the sheath 52 and pushes the stent 1 for implantation in a living body out from the tip of the sheath 52.

[0051] The in vivo stent 1 is as described above. The stent delivery system 50 of this embodiment comprises a sheath 52, a self-expanding in vivo stent 1, and an inner tube 54, as shown in Figure 6.

[0052] As shown in Figures 6, 7, and 9, the sheath 52 is tubular and has openings at its tip and rear end. The tip opening functions as a discharge port for the in vivo stent 1 when it is placed in a narrowed area within a body cavity. The in vivo stent 1 is pushed out through this tip opening, releasing the stress load and expanding to return to its pre-compression shape. The tip of the sheath 52 is a stent housing section 55 that houses the in vivo stent 1 inside. The sheath 52 also has a side hole 41 provided on the proximal end side of the stent housing section 55. The side hole 41 is for guiding the guide wire to the outside.

[0053] Furthermore, as shown in Figures 6 and 8, a sheath hub 56 is fixed to the base end of the sheath 52. As shown in Figure 8, the sheath hub 56 comprises a sheath hub body 61 and a valve body 62 housed within the sheath hub body 61, which slidably and liquid-tightly holds the inner tube 54. The sheath hub 56 also has a side port 63 that branches diagonally rearward from near the center of the sheath hub body 61.

[0054] Furthermore, the sheath hub 56 is equipped with an inner tube locking mechanism that restricts the movement of the inner tube 54. In this embodiment, the locking mechanism consists of a valve body 62 that clamps the base end of the inner tube 54 in a liquid-tight manner by compression, an operating member 64 that compresses the valve body 62, and the sheath hub body 61. By providing this locking mechanism, the inner tube 54 can be fixed in any position relative to the sheath 52. The valve body 62 is installed in a valve body housing recess provided at the base end of the sheath hub body 61, and an inner tube insertion passage that forms part of the inner tube lumen is formed inside the valve body 62. In addition, the inner diameter of the valve body housing recess is made slightly larger than the outer diameter of the valve body 62, allowing the valve body 62 to expand radially when compressed by the operating member 64. The internal shape of the valve body 62 (in other words, the shape of the inner tube insertion passage) is made into a shape in which two substantially spherical shapes partially overlap in the axial direction, with both ends and the center part having a reduced diameter.

[0055] The operating member 64 has a cylindrical valve body pressing portion 64a protruding towards the tip in the central part, an inner cylindrical portion 64c formed to enclose the valve body pressing portion 64a and having a screw portion 64b that can be screwed into a screw portion 61a formed on the outer surface of the rear end of the sheath hub body 61, and a cylindrical gripping portion 64d formed to enclose the inner cylindrical portion 64c. The gripping portion 64d is the part used to grip the operating member 64 when it is rotated. Furthermore, an internal passage is formed inside the valve body pressing portion 64a, specifically inside the valve body pressing portion 64a, forming part of the lumen for the inner tube. Also, as shown in Figure 4, the tip portion of the valve body pressing portion 64a is inserted into the recess for housing the valve body, and the valve body 62 can be compressed by moving the operating member to the tip.

[0056] In this embodiment of the locking mechanism, when the operating member 64 is rotated to advance the screwing process so that it moves toward the tip of the sheath hub 56, the tip of the valve body pressing portion 64a comes into contact with the rear end of the valve body 62. Further rotation of the operating member 64 to advance the screwing process compresses the valve body 62 in the axial direction. As the compression of the valve body 62 progresses, the inner diameter of the internal passage decreases, and finally the inner tube 54 is gripped and fixed by the valve body 62. The locking mechanism is released by the reverse rotation operation described above.

[0057] Furthermore, a reinforcing tube 66 is provided between the base end of the sheath 52 and the sheath hub 56, extending from the tip of the sheath hub 56 toward the tip. This reinforcing tube 66 prevents kinking of the sheath 52 at the tip of the sheath hub 56. It is preferable to use a heat-shrinkable tube as the reinforcing tube.

[0058] As shown in Figures 6, 7, and 8, the inner tube 54 comprises a shaft-shaped inner tube body portion 40, a tip portion 47 provided at the tip of the inner tube body portion 40 and protruding from the tip of the sheath 52, and an inner tube hub 70 fixed to the base end of the inner tube body portion 40.

[0059] The tip portion 47 preferably protrudes from the tip of the sheath 52 and is tapered, gradually decreasing in diameter towards the tip, as shown in Figure 7. This configuration facilitates insertion into the stenosis. Furthermore, the inner tube 54 is preferably located on the tip side of the in-vivo stent 1 and is equipped with a stopper to prevent the sheath from moving toward the tip. The base end of the tip portion 47 is capable of contacting the tip of the sheath 52 and functions as the stopper described above.

[0060] Furthermore, as shown in Figure 7, the inner tube 54 is provided with two protrusions 43 and 45 for holding the in vivo stent 1. The protrusions 43 and 45 are preferably annular. A stent-holding protrusion 43 is provided on the proximal end side of the tip 47 of the inner tube 54. The in vivo stent 1 is positioned between the two protrusions 43 and 45. Therefore, the area between these two protrusions 43 and 45 in the stent delivery system 50 is the stent storage area 55. In other words, the inner tube 54 is provided with a stent extrusion protrusion 45 located on the proximal end side of the stent storage area 55, and a stent-holding protrusion 43 located on the tip side of the stent storage area 55. The outer diameters of these protrusions 43 and 45 are sized to be in contact with the compressed in vivo stent 1, which will be described later. Therefore, the in vivo stent 1 is restricted from moving toward the tip by the protruding portion 43 and from moving toward the proximal end by the protruding portion 45. Then, as shown in Figure 9, when the sheath 52 moves backward, the in vivo stent 1 is exposed by the sheath 52, expands, and is eventually discharged as a whole.

[0061] As shown in Figure 7, the inner tube 54 includes a lumen 48 that extends from its tip at least to the proximal end side of the stent housing portion 55 of the sheath 52, and an inner tube side hole 42 that communicates with the lumen 48 on the proximal end side of the stent housing portion. In this embodiment of the stent delivery system 50, the lumen 48 terminates at the location where the inner tube side hole 42 is formed. The lumen 48 is for inserting one end of a guide wire from the tip of the stent delivery system 50, partially inserting it into the inner tube, and then leading it out to the outside from the side of the inner tube. The inner tube side hole 42 is located slightly towards the tip of the stent delivery system 50 from the sheath side hole 21.

[0062] The inner tube 54 penetrates the sheath 52 and protrudes from the rear end opening of the sheath 52. An inner tube hub 70 is fixed to the base end of the inner tube 54, as shown in Figures 6 and 9.

[0063] Furthermore, in the stent delivery system of this embodiment, a rigid pipe 72 is fitted over the base end of the inner tube 54. This rigid pipe 72 extends a predetermined distance toward the tip from the base end of the inner tube 54, and at least the tip of the pipe 72 penetrates into the sheath hub 56 and extends to a position that is toward the tip of the valve body 62. Furthermore, it is preferable that the base end of the inner tube 54 is provided with an insertion depth restricting portion that restricts the distance the sheath 52 moves toward the tip. The inner tube 54 is provided with an insertion depth restricting tube 73 at its base end. The outer diameter of this tube 73 is larger than the inner diameter of the passage of the operating member 64 of the sheath hub 56, and it is impossible for it to penetrate into the sheath hub 56.

[0064] Next, the method of using the stent delivery system 50 of the present invention will be explained with reference to the drawings. First, as shown in Figure 9, the rear end 9a of the guide wire 9 is inserted from the tip of the lumen 48 of the inner tube 54, and is led out to the outside by passing it through the side hole 42 of the inner tube 54 and the side hole 21 of the sheath 52. Then, the sheath 52 is grasped and the stent delivery system 50 of the present invention is inserted into a body cavity (for example, a blood vessel) along the guide wire 9 to position the target in vivo stent 1 for placement in the stenotic area.

[0065] Next, the sheath 52 is moved axially towards the proximal end. At this time, the rear end face of the in vivo stent 1 abuts against the tip surface of the stent extrusion projection 45 and is locked in place, so it is released from the tip opening of the sheath 52 as the sheath 52 moves. As a result of this release, the in vivo stent 1 expands itself, as shown in Figure 9, and expands the stenosis, and is then placed within the stenosis. After that, the inner tube 54 is moved axially towards the proximal end and stored inside the sheath 52, and the procedure is completed by removing the sheath 52 together with the inner tube 54 from the body cavity.

[0066] The self-expanding in vivo stent of the present invention is formed in a cylindrical shape, and is a self-expanding in vivo stent that can be reduced in diameter by compression in the direction of the central axis and restored to its original shape by releasing the compression. The in vivo stent comprises a stent body, which comprises a plurality of annular bodies that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the annular bodies when the plurality of annular bodies are arranged in the axial direction of the stent body. The annular body is formed from a wavy linear component having multiple bent sections with vertices at one end and the other end in the axial direction. Between adjacent annular bodies in the axial direction of the in vivo implantable stent, the vertices of the adjacent bent sections are offset by a predetermined length in the circumferential direction of the stent body. The connection section comprises a first pattern connection section extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection section extending at a predetermined angle oblique to the central axis of the stent body and in a different direction from the first pattern connection section. The connection section between opposing annular bodies is either the first pattern connection section or the second pattern connection section, and is the same pattern connection section. The connection sections adjacent to each other in the axial direction of the stent body are arranged so that the first pattern connection section and the second pattern connection section alternate. Therefore, even when implanted in a stenotic area due to calcification in the lower limb artery, it exhibits good expansion force even in the calcified lesion and has the flexibility to withstand bending, twisting, and other loads caused by external forces on the superficial femoral artery.

[0067] Embodiments of the in vivo stent of the present invention are as follows: (1) A self-expanding in vivo stent formed in a cylindrical shape, which can be reduced in diameter by compression in the direction of the central axis and restored to its original shape by releasing the compression, wherein the in vivo stent comprises a stent body, the stent body comprises a plurality of annular bodies that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the annular bodies in a state in which the plurality of annular bodies are arranged in the axial direction of the stent body, The annular body is formed of a wavy linear component having a plurality of bent portions with vertices on one end and the other end in the axial direction, and between adjacent annular bodies in the axial direction of the in vivo stent, the vertices of the adjacent bent portions are offset by a predetermined length in the circumferential direction of the stent body, and the connection portion comprises a first pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body and in a direction different from the first pattern connection portion, and the connection portion between opposing annular bodies is either the first pattern connection portion or the second pattern connection portion, and the connection portions adjacent to the stent body in the axial direction are arranged such that the first pattern connection portion and the second pattern connection portion alternate.

[0068] This self-expanding in vivo stent is formed in a cylindrical shape and can be reduced in diameter by compression in the central axis direction and restored to its original shape by releasing the compression. The in vivo stent comprises a stent body, which comprises a plurality of annular bodies that can deform in a direction that reduces the outer diameter when stress is applied, and connecting parts that connect the annular bodies when the plurality of annular bodies are arranged in the axial direction of the stent body. The annular body is formed from a wavy linear component having multiple bent sections with vertices at one end and the other end in the axial direction. Between adjacent annular bodies in the axial direction of the in vivo implantable stent, the vertices of the adjacent bent sections are offset by a predetermined length in the circumferential direction of the stent body. The connection section comprises a first pattern connection section extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection section extending at a predetermined angle oblique to the central axis of the stent body and in a different direction from the first pattern connection section. The connection section between opposing annular bodies is either the first pattern connection section or the second pattern connection section, and is the same pattern connection section. The connection sections adjacent to each other in the axial direction of the stent body are arranged so that the first pattern connection section and the second pattern connection section alternate. Therefore, even when implanted in a stenotic area due to calcification in the lower limb artery, it exhibits good expansion force even in the calcified lesion and has the flexibility to withstand bending, twisting, and other loads caused by external forces on the superficial femoral artery.

[0069] Furthermore, embodiments of the in vivo stent of the present invention are as follows: (2) A self-expanding in vivo stent formed in a cylindrical shape, which is reduced in diameter when inserted into a body and can be restored to its pre-reduced shape when implanted in a body, wherein the in vivo stent comprises a stent body, the stent body comprises a plurality of annular bodies that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the annular bodies in a state in which the plurality of annular bodies are arranged in the axial direction of the stent body, The annular body is formed of a wavy linear component having a plurality of bent portions with vertices on one end and the other end in the axial direction, and between adjacent annular bodies in the axial direction of the in vivo implantable stent, the vertices of the adjacent bent portions are offset by a predetermined length in the circumferential direction of the stent body, and the connection portion comprises a first pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body and in a direction different from the first pattern connection portion, and the connection portion between opposing annular bodies is either the first pattern connection portion or the second pattern connection portion, and the connection portions adjacent to each other in the axial direction of the stent body are arranged so that the first pattern connection portion and the second pattern connection portion alternate. Furthermore, the stent body comprises two maximum connection portion holders having connection portions between all adjacent vertices of the annular bodies at both ends of the stent body, two first reduced connection portion holders having 40 to 60% of the number of connection portions in the maximum connection portion holders between the annular bodies having the maximum connection portion holders and the annular bodies located axially inward of the stent body, and a second reduced connection portion holder having 40 to 60% of the number of connection portions in the first reduced connection portion holders between a plurality of annular bodies located between the two first reduced connection portion holders, wherein the space between the annular bodies has a second reduced connection portion holder having 40 to 60% of the number of connection portions in the first reduced connection portion holders.

[0070] Furthermore, the following embodiments of the above-mentioned in vivo stent may also be: (3) The in vivo stent according to (1) or (2) above, wherein the axial length of the annular body during self-expansion is 1.3 to 1.7 mm. (4) The in vivo stent according to any one of (1) to (3) above, wherein the length of the connecting portion is 0.35 to 0.50 mm. (5) The inclination angle of the connecting portion with respect to the central axis of the stent body during self-expansion of the annular body is 110 to 130 degrees. (6) The in vivo stent according to any one of (1) to (5) above, wherein the number of vertices on one end and the other end of the annular body is 12 to 20, respectively. (7) The in vivo stent according to any one of (1) to (6) above, wherein the outer diameter of the in vivo stent during self-expansion is 4.0 to 10.0 mm. (8) The in vivo stent according to any one of (1) to (7) above, wherein the axial length of the in vivo stent during self-expansion is 30 to 200 mm. (9) The in vivo stent according to any one of (1) to (8) above, wherein the axial length of the in vivo stent during self-expansion is 120 to 170 mm. (10) The in vivo stent according to any one of (1) to (9) above, wherein the ratio of the outer surface area occupied by the outer surface of the stent body to the outer surface area of ​​the virtual cylindrical body during self-expansion is 15% to 20%. (11) The in vivo stent according to any one of (1) to (10) above, wherein the number of axial directions of the annular body is 7 to 100. (12) The in vivo stent according to any one of (1) to (11) above, wherein, when the in vivo stent is self-expanding, it has a plurality of lateral openings formed in adjacent annular bodies, and the maximum inscribed circle radius at each lateral opening is 0.37 to 0.45 mm. (13) The in vivo stent according to any one of (1) to (12) above, wherein when the central part of the in vivo stent is curved with a radius of curvature R of 7.5 mm, the diameter retention rate at the central part is 85% or more.(14) The in vivo stent is the in vivo stent according to any one of (1) to (13) above, wherein the expansion force is 9 to 11 N / cm. (15) The in vivo stent is the in vivo stent according to any one of (1) to (14) above, wherein the in vivo stent is provided with a drug-containing coating on the outer surface of the stent body. (16) The in vivo stent according to (15) above, wherein the drug-containing coating contains sirolimus or a sirolimus derivative as the drug. (17) The in vivo stent according to any one of (1) to (16) above, wherein the axial length of the annular body during self-expansion is 1.4 to 1.6 mm.

[0071] Embodiments of the stent delivery system of the present invention are as follows: (18) A stent delivery system comprising a sheath, a stent for implantation in a living body as described in any of (1) to (17) above, housed in the tip of the sheath, and an inner tube that is slidably inserted through the sheath and for pushing the stent for implantation in a living body out from the tip of the sheath.

Claims

1. A self-expanding in vivo stent formed in a cylindrical shape, which can be reduced in diameter by compression in the direction of the central axis and restored to its original shape by releasing the compression, wherein the in vivo stent comprises a stent body, the stent body comprises a plurality of annular bodies that can be deformed in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the plurality of annular bodies in a state in which the annular bodies are arranged in the axial direction of the stent body, The annular body is formed of a wavy linear component having a plurality of bent portions with vertices on one end and the other end in the axial direction, and between adjacent annular bodies in the axial direction of the in vivo stent, the vertices of the adjacent bent portions are offset by a predetermined length in the circumferential direction of the stent body, and the connection portion comprises a first pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body and a second pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body and in a direction different from the first pattern connection portion, and the connection portion between opposing annular bodies is either the first pattern connection portion or the second pattern connection portion, and the connection portions adjacent to the stent body in the axial direction are arranged such that the first pattern connection portion and the second pattern connection portion alternate.

2. A self-expanding in vivo stent formed in a cylindrical shape, which is reduced in diameter when inserted into a body and can be restored to its original shape when placed in a body, wherein the in vivo stent comprises a stent body, the stent body comprises a plurality of annular bodies that can deform in a direction in which the outer diameter is reduced when stress is applied, and connecting parts that connect the plurality of annular bodies in a state in which the annular bodies are arranged in the axial direction of the stent body, The annular body is formed of a wavy linear component having a plurality of bent portions with vertices on one end and the other end in the axial direction, and between adjacent annular bodies in the axial direction of the in vivo implantable stent, the vertices of the adjacent bent portions are offset by a predetermined length in the circumferential direction of the stent body, and the connection portion comprises a first pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body, and a second pattern connection portion extending at a predetermined angle oblique to the central axis of the stent body and in a direction different from the first pattern connection portion, and the connection portion between opposing annular bodies is either the first pattern connection portion or the second pattern connection portion, and the connection portions adjacent to each other in the axial direction of the stent body are arranged so that the first pattern connection portion and the second pattern connection portion alternate. Furthermore, the stent body is characterized in that it has two maximum connection portion holders, each having a connection portion between all adjacent vertices of the annular bodies at both ends of the stent body; two first reduced connection portion holders, each having 40 to 60% of the number of connection portions in the maximum connection portion holders between the annular bodies having the maximum connection portion holders and the annular bodies located axially inward of the stent body; and a second reduced connection portion holder, each having 40 to 60% of the number of connection portions in the first reduced connection portion holders, between a plurality of annular bodies located between the two first reduced connection portion holders.

3. The in vivo stent according to claim 1 or 2, wherein the axial length of the annular body during self-expansion is 1.3 to 1.7 mm.

4. The in vivo stent according to claim 3, wherein the length of the connecting portion is 0.35 to 0.50 mm.

5. The in-vivo stent according to claim 4, wherein the inclination angle of the connecting portion with respect to the central axis of the stent body during the self-expansion of the annular body is 110 to 130 degrees.

6. The in vivo stent according to claim 1 or 2, wherein the number of vertices on one end and the other end of the annular body is 12 to 20, respectively.

7. The in vivo stent according to claim 1 or 2, wherein the outer diameter of the in vivo stent during self-expansion is 4.0 to 10.0 mm.

8. The in vivo stent according to claim 1 or 2, wherein the axial length of the in vivo stent during self-expansion is 30 to 200 mm.

9. The in vivo stent according to claim 1 or 2, wherein the axial length of the in vivo stent during self-expansion is 120 to 170 mm.

10. The in vivo stent according to claim 1 or 2, wherein the ratio of the outer surface area of ​​the stent body to the outer surface area of ​​the virtual cylindrical body during the self-expansion of the in vivo stent is 15% to 20%.

11. The in vivo stent according to claim 1 or 2, wherein the number of annular bodies in the axial direction is 7 to 100.

12. The in vivo stent according to claim 1 or 2, wherein, during self-expansion, the in vivo stent has a plurality of lateral openings formed within adjacent annular bodies, and the maximum inscribed circle radius of each lateral opening is 0.37 to 0.45 mm.

13. The in vivo stent according to claim 1 or 2, wherein the diameter retention rate at the central part of the in vivo stent when the central part of the in vivo stent is curved with a radius of curvature R7.5 mm is 85% or more.

14. The in vivo stent according to claim 1 or 2, wherein the in vivo stent has an expansion force of 9 to 11 N / cm.

15. The in vivo stent according to claim 1 or 2, wherein the in vivo stent comprises a drug-containing coating provided on the outer surface of the stent body.

16. The in vivo stent according to claim 15, wherein the drug-containing coating portion contains sirolimus or a sirolimus derivative as the drug.

17. The in vivo stent according to claim 1 or 2, wherein the axial length of the annular body during self-expansion is 1.4 to 1.6 mm.

18. A stent delivery system comprising a sheath, a stent for in-vivo implantation according to claim 1 or 2 housed within the tip of the sheath, and an inner tube slidably inserted through the sheath for pushing the stent for in-vivo implantation out from the tip of the sheath.

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