Covered stent

Abstract

The invention discloses a covered stent, which relates to the technical field of interventional medical instruments and comprises a covered stent section and bare stent sections connected to two axial ends of the covered stent section. The covered stent section comprises a stent main body in a pipe network shape and a tubular covering film covering the surface of the stent main body; the bare stent section comprises a bare stent connected to the axial end part of the covered stent section; the bare stent is formed by weaving a first metal wire in a spiral spring shape, and the stent main body is formed by weaving a second metal wire in a spiral spring shape; and the bare stent is loaded with an anti-hyperplasia drug. The bare stents are arranged at the two ends of the covered stent section, the anti-hyperplasia medicine is loaded on the bare stents, the bare stents are formed by weaving the first metal wires in the spiral spring shape, the bare stents can better conform to the inner cavity of a blood vessel, stimulation to the blood vessel is reduced, and therefore hyperplasia of smooth muscle cells of the blood vessel is reduced; the anti-hyperplasia drug can inhibit hyperplasia of vascular smooth muscle cells, and finally the situation that the two ends of the covered stent are narrow is prevented or reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of interventional medical devices, and in particular to a stent graft. Background Art

[0002] Covered stents are mainly used to solve problems related to vascular stenosis, aneurysms and other vascular access. Covered stents refer to stents coated with special membrane materials (polytetrafluoroethylene, Dacron, polyester, polyurethane, etc.) on metal stents. Covered stents provide a tubular support structure in the blood vessels to mechanically keep the blood vessels in an open state. In stenotic lesions, the obstructive effect of the membrane may prevent the migration caused by the secretion of inflammatory mediators by macrophages in the damaged vascular walls of the diseased vessels, which helps to reduce the effects of cytokines, metalloproteinases, growth factors, etc. related to restenosis on the vascular wall. Compared with bare metal stents, covered stents can reduce the occurrence of vascular restenosis.

[0003] However, it is found in practice that the existing stent grafts still have restenosis at the edges of the stent grafts. How to prevent the stent grafts from restenosis is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] In view of this, the present invention provides a stent graft to solve the problem that blood vessels are prone to restenosis at both end edges of the existing stent graft.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows: A stent graft, comprising: The coated stent segment comprises a stent body in a tubular network shape and a tubular coating covering the surface of the stent body; The bare stent segment includes bare stents connected to the two axial ends of the coated stent segment; the bare stent is woven by a first metal wire in the shape of a spiral spring.

[0006] By adopting the above technical solution, the bare stents at both ends of the axial direction of the coated stent segment are woven with the first metal wire in the shape of a spiral spring. Compared with the traditional bare stent formed by weaving cylindrical metal wires, it has better flexibility and elastic bending performance. Not only is the bending performance good, but the first metal wire in the shape of a spiral spring can be more evenly distributed on the bare stent, providing a more uniform radial support force, reducing local stress concentration, and can better conform to the vascular lumen, reduce stimulation to the blood vessel, and reduce the risk of restenosis of the bare stent due to self-collapse in a narrow or diseased blood vessel. In addition, this bare stent can quickly return to its original shape when repeatedly bent and stretched, is not prone to permanent deformation, and has a longer service life; this bare stent has better stretching performance, can provide a better anchoring effect, reduce the risk of displacement of the coated stent in the blood vessel, and improve the treatment effect.

[0007] Furthermore, the bare stent is provided with anti-proliferative drugs.

[0008] By adopting the above technical solution, the anti-proliferative drug on the bare stent can reduce tissue proliferation at the position of the blood vessel corresponding to the bare stent, thereby reducing the risk of restenosis of the blood vessel.

[0009] Furthermore, a concave hole is provided on the first metal wire of the bare stent, and the anti-proliferative drug is arranged in the concave hole.

[0010] By adopting the above technical solution, the structural setting of the anti-proliferative drug on the concave hole of the bare stent can achieve the slow release of the anti-proliferative drug. The blood vessel corresponding to the bare stent position is exposed to the anti-proliferative drug for a long time, and tissue hyperplasia is not likely to occur, further reducing the risk of vascular restenosis.

[0011] Furthermore, the anti-proliferative drugs include but are not limited to any one or more of heparin, rapamycin and its derivatives, paclitaxel and its derivatives.

[0012] Furthermore, the bare stent is spiral-shaped, and includes a plurality of first spiral turns formed by a single first metal wire spirally wrapped along the axial direction of the coated stent, and the first spiral turns have a plurality of first wave peaks and a plurality of first wave valleys alternately arranged in the circumferential direction.

[0013] By adopting the above technical solution, a bare stent with this structure can provide better radial supporting force.

[0014] Furthermore, first wave crests of two adjacent circles of the first spiral circle are correspondingly arranged in the axial direction of the stent graft, and first wave troughs of two adjacent circles of the first spiral circle are correspondingly arranged in the axial direction of the stent graft.

[0015] Furthermore, part of the first metal wire of the bare stent is tilted outward relative to the outer circumference of the bare stent to form an anchoring structure.

[0016] By adopting the above technical solution, the anchoring structure formed by the outward-bending first trough on the first spiral coil can improve the anchoring effect of the bare stent, improve the overall anti-displacement ability of the coated stent, and thus improve safety.

[0017] Furthermore, the first spiral circle of the bare stent that is farthest from the coated stent segment is an end spiral circle, and the anchoring structure is formed by a plurality of first wave valleys on the end spiral circle that are tilted outward relative to the outer circumference of the bare stent.

[0018] Furthermore, a developing material layer is provided on the first metal wire of the bare bracket; or a developing ring is sleeved on the first metal wire of the bare bracket; or a developing wire is provided in the internal space surrounded by the first metal wire of the bare bracket.

[0019] By adopting the above technical solution, since the first metal wire in the shape of a spiral spring has higher visibility under X-ray or other imaging technology, it is convenient for doctors to accurately identify the position of the bare stent in the patient's body during surgery; and the arrangement of the developing material layer, the developing ring or the developing wire on the first metal wire can further improve the visualization effect of the bare stent. In addition, when the developing wire is inserted into the internal space surrounded by the spiral winding of the first metal wire, the developing wire not only has the effect of making the bare stent visible, but also has a certain supporting effect on the bare stent, which is conducive to further improving the ability of the bare stent to resist external pressure and reducing the risk of restenosis of the bare stent due to self-collapse in a narrow or diseased blood vessel.

[0020] Furthermore, the stent body is woven from a second metal wire in the shape of a spiral spring.

[0021] By adopting the above-mentioned technical scheme, a stent body woven with a second metal wire in the shape of a spiral spring can be used to improve the bending performance of the coated stent segment and the entire coated stent, which can more easily pass through curved and narrow parts of the blood vessel and reduce damage to the blood vessel wall. It can better conform to the natural shape of the blood vessel, reduce the pressure of the coated stent on the blood vessel wall, and improve the comfort and safety of the patient.

[0022] Furthermore, the stent body is spiral-shaped, and includes a plurality of annular wave rings formed in sequence along the axial direction of the stent graft; the annular wave rings have a plurality of second wave crests and a plurality of second wave troughs alternately arranged in the circumferential direction.

[0023] Furthermore, the second wave crests of two adjacent circles of the annular wave rings are correspondingly arranged in the axial direction of the stent graft, and the second wave troughs of two adjacent circles of the annular wave rings are correspondingly arranged in the axial direction of the stent graft.

[0024] Furthermore, the first metal wire of the bare stent is indirectly connected to the stent body through the coating or other connecting structure, or the first metal wire of the bare stent and the second metal wire of the stent body are the same metal wire formed in one piece.

[0025] Furthermore, the coating is coated on the inner surface of the stent body, and / or the coating is coated on the outer surface of the stent body.

[0026] By adopting the above technical solution, the coating on the outer surface of the stent body can block the blood vessel wall tissue, preventing excessive blood vessel proliferation and restenosis, so that after the coated stent is implanted in the blood vessel, blood can flow smoothly through the coated stent. The coating on the outer surface of the stent body can form a smoother surface, reduce the generation of blood turbulence and eddy currents, and improve hemodynamic characteristics. At the same time, the smooth surface of the coating can reduce intimal hyperplasia, reduce the risk of thrombosis, and prolong the patency time of the coated stent.

[0027] Furthermore, the coating is an expanded polytetrafluoroethylene film, a fluorinated ethylene propylene copolymer film or a silicone film.

[0028] The technical solution of the present invention has the following advantages: by arranging bare stents at both ends of the covered stent segment, and carrying anti-proliferative drugs on the bare stents, it is possible to prevent the blood vessels from restenosis at both ends of the covered stent; and the bare stent is woven from a first metal wire in the shape of a spiral spring, and compared with the bare stent formed by the traditional cylindrical metal wire, it has good bending performance, can better conform to the vascular lumen, reduce the stimulation to the blood vessel, thereby reducing the proliferation of vascular smooth muscle cells, and cooperate with anti-proliferative drugs to finally prevent or reduce the stenosis at both ends of the covered stent. In addition, the bare stent adopts a partially raised structure, which can improve the anchoring of the bare stent and improve the anti-displacement ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 Schematic diagram of the three-dimensional structure of the stent graft in an embodiment of the present invention; Figure 2 is a side view of a stent graft according to an embodiment of the present invention; Figure 3 It is a schematic structural diagram of a first metal wire of a bare stent in an embodiment of the present invention; Figure 4 Schematic diagram of the end of a bare stent in an embodiment of the present invention; Figure 5 Schematic diagram of partial tilting of the bare stent in the embodiment of the present invention Figure 1 ; Figure 6 Schematic diagram of partial tilting of the bare stent in the embodiment of the present invention Figure 2 ; Figure 7 Schematic diagram of the structure of the concave hole on the bare stent in an embodiment of the present invention; Figure 8 It is a schematic diagram of the structure when a developing wire is inserted into the first metal wire of a bare stent in an embodiment of the present invention.

[0031] Explanation of reference numerals: 100, coated stent segment; 110, stent body; 120, coating; 200, bare stent segment; 210, bare stent; 211, concave hole; 210a, first wave crest; 210b, first wave trough; 220, anchoring structure; 300, developing wire. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of this application, it should be understood that the terms "proximal end" and "distal end" used throughout the text refer to near and far relative to the operator. When the present invention is used, the end close to the doctor or operator is the "proximal end", that is, the end where the operator is located, and the end away from the doctor or operator is the "distal end", that is, the end where the balloon is located. The above-mentioned description of the orientation is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0034] In the description of this application, it should be noted that the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0035] like Figure 1 and Figure 2 A coated stent is shown, comprising a coated stent segment 100 and two bare stent segments 200 connected to the axial ends of the coated stent segment 100. The coated stent segment 100 comprises a stent body 110 in a tubular network shape, and a tubular coating 120 covering the surface of the stent body 110; the bare stent segment 200 comprises a bare stent 210 connected to the axial ends of the coated stent segment 100. The bare stent 210 is woven with a first metal wire in a spiral spring shape, and the stent body 110 is woven with a second metal wire in a spiral spring shape. The first metal wire and the second metal wire are made of materials with good biocompatibility such as nickel titanium or stainless steel.

[0036] In some embodiments, the first metal wire of the bare stent 210 is indirectly connected to the coated stent through the coating 120 or other connection structures. In other alternative embodiments, the first metal wire of the bare stent 210 and the second metal wire of the stent body 110 are the same metal wire formed in one piece.

[0037] like Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the bare stent 210 is spiral-shaped. The bare stent 210 includes a plurality of first spiral turns formed by a single first metal wire spirally wrapped along the axial direction of the coated stent, and the first spiral turns have a plurality of first wave crests 210a and a plurality of first wave troughs 210b alternately arranged in the circumferential direction; the first wave crests 210a of two adjacent first spiral turns are correspondingly arranged in the axial direction of the coated stent, and the first wave troughs 210b of two adjacent first spiral turns are also correspondingly arranged in the axial direction of the coated stent. Figure 2 As shown, in some embodiments, the stent body 110 includes a plurality of annular coils arranged in parallel and spaced relation along the axial direction of the coated stent, each annular coil is wound by a second metal wire in the shape of a spiral spring, and the plurality of annular coils are connected as a whole by the coating 120; the annular coils have a plurality of wave crests and a plurality of wave troughs arranged alternately in the circumferential direction. In other alternative embodiments, the stent body 110 may also adopt a spiral structure similar to that of the bare stent 210, that is, the stent body 110 includes a plurality of second spiral coils formed by a single second metal wire spirally wound along the axial direction of the coated stent, and the second spiral coils have a plurality of second wave crests and a plurality of second wave troughs arranged alternately in the circumferential direction; the second wave crests of two adjacent annular coils are arranged in corresponding positions in the axial direction of the coated stent, and the second wave troughs of two adjacent annular coils are arranged in corresponding positions in the axial direction of the coated stent.

[0038] Compared with the traditional bare stent 210 and stent body 110 formed by weaving cylindrical metal wires, the bare stent 210 and stent body 110 formed by weaving spiral spring-shaped metal wires have better flexibility and elastic bending performance. Not only do they have good bending performance, they can also smoothly pass through the curved and narrow parts of the blood vessels, reduce the stimulation to the blood vessel walls, thereby reducing the proliferation of vascular smooth muscle cells, and can better conform to the natural morphology of the blood vessels, reduce the pressure of the coated stent on the blood vessel walls, and improve the comfort of the patients; moreover, the metal wires on the bare stent 210 and the stent body 110 are evenly distributed, which can provide more uniform radial support force and reduce local stress concentration, so that the bare stent 210 at the two end edges of the coated stent is not easy to collapse under external pressure, reducing the risk of restenosis of the bare stent 210 due to its own collapse in narrow or diseased blood vessels. In addition, the bare stent 210 and the stent body 110 can quickly return to their original shape after repeated bending and stretching, and are not prone to permanent deformation, so the service life of the coated stent is longer. Moreover, due to its better stretching performance, the bare stent 210 can also provide a better anchoring effect, reduce the risk of displacement of the coated stent in the blood vessel, and improve the treatment effect.

[0039] like Figure 2 As shown, in some embodiments, when the stent body 110 includes a plurality of annular waves arranged in parallel and at intervals, the interval between two adjacent first spiral circles on the bare stent 210 is equal to the interval between two adjacent annular waves on the stent body 110. When the stent body 110 is formed by a single second metal wire spirally wrapped along the axial direction of the coated stent, the helical rise angle of the first spiral circle on the bare stent 210 is smaller than the helical rise angle of the annular waves on the stent body 110; intuitively, the density of the metal wires on the bare stent 210 is greater than the density of the metal wires on the stent body 110. With such a configuration, the radial support force of the bare stent 210 can be greater than the radial support force of the stent body 110, making the bare stent 210 relatively less prone to collapse.

[0040] like Figure 5 and Figure 6 As shown, part of the first metal wire of the bare stent 210 is tilted outward relative to the outer circumference of the bare stent 210 to form an anchoring structure 220, and multiple anchoring structures 220 are evenly arranged around the circumference of the bare stent 210. The provision of multiple anchoring structures 220 can improve the anchoring effect of the bare stent 210, and improve the anti-displacement ability of the coated stent as a whole, thereby improving safety. In some embodiments, the first spiral circle of the bare stent 210 farthest from the coated stent segment 100 is the end spiral circle, and the anchoring structure 220 is formed by multiple first troughs 210b on the end spiral circle tilting outward relative to the outer circumference of the bare stent 210. In other alternative embodiments, the anchoring structure 220 can also be arranged on multiple circles of the first spiral circle.

[0041] In some embodiments, an anti-proliferative drug is provided on the bare stent 210, and the anti-proliferative drug includes but is not limited to any one or more of heparin, rapamycin and its derivatives, paclitaxel and its derivatives. The anti-proliferative drug can reduce tissue hyperplasia at the position of the blood vessel corresponding to the bare stent 210, and reduce the risk of restenosis of the blood vessel.

[0042] like Figure 7 As shown, a plurality of recessed holes 211 are provided on the first metal wire of the bare stent 210, and the anti-proliferative drug is provided in the plurality of recessed holes 211. The openings of the plurality of recessed holes 211 are arranged to face outward, and when the coated stent is located in the blood vessel, the openings of the recessed holes 211 face the blood vessel wall. The structural form in which the anti-proliferative drug is provided on the recessed holes 211 can realize the slow release of the anti-proliferative drug, and the blood vessel wall corresponding to the position of the bare stent 210 is subjected to the action of the anti-proliferative drug for a long time, and tissue hyperplasia is not likely to occur, thereby further reducing the risk of restenosis of the blood vessel. In other alternative embodiments, the anti-proliferative drug can also be applied to the surface of the bare stent 210 in the form of a drug coating.

[0043] like Figure 8 As shown, in some embodiments, the internal space surrounded by the first metal wire of the bare stent 210 is provided with a developing wire 300. Since the first metal wire in the shape of a spiral spring has higher visibility under X-ray or other imaging techniques, it is convenient for doctors to accurately identify the position of the bare stent 210 in the patient's body during surgery; and the setting of the developing wire 300 on the first metal wire can further improve the visualization effect of the bare stent 210. At the same time, the developing wire 300 has a certain supporting effect on the bare stent 210, which is conducive to further improving the ability of the bare stent 210 to resist external pressure and reducing the risk of restenosis of the bare stent 210 due to self-collapse in a narrow or diseased blood vessel. In other alternative embodiments, a developing material layer is provided on the first metal wire of the bare stent 210, or a developing ring is sleeved on the first metal wire of the bare stent 210.

[0044] In some embodiments, the coating 120 can be coated on the inner surface of the stent body 110, the coating 120 can also be coated on the outer surface of the stent body 110, or the coating 120 is coated on both the inner and outer surfaces of the stent body 110. The material of the coating 120 is an expanded polytetrafluoroethylene film, a fluorinated ethylene propylene copolymer film, or a silicone film. The barrier effect of the coating 120 on the outer surface of the stent body 110 on the vascular wall tissue can prevent excessive proliferation of the blood vessels from causing restenosis, so that after the coated stent is implanted in the blood vessel, the blood flow passes smoothly through the coated stent. The coating 120 on the outer surface of the stent body 110 can form a smoother surface, reduce the generation of blood turbulence and eddy currents, and improve the hemodynamic characteristics. At the same time, the smooth surface of the coating 120 can reduce intimal hyperplasia, reduce the risk of thrombosis, and prolong the patency time of the coated stent.

[0045] In summary, the coated stent provided in the embodiment of the present invention is provided with bare stents 210 at both ends of the coated stent segment 100. The bare stent 210 is woven with a first metal wire in the shape of a spiral spring. Compared with the bare stent 210 formed by weaving a traditional cylindrical metal wire, it has better flexibility and elastic bending performance. It not only has good bending performance, but also can better resist external pressure, and reduce the risk of restenosis of the bare stent 210 due to self-collapse in a narrow or diseased blood vessel. The anti-proliferative drugs on the bare stent 210 can further prevent the blood vessels from restenosis at both ends of the coated stent. In addition, the bare stent 210 adopts a partially raised structure, which can improve the anchoring of the bare stent 210 and improve the anti-displacement ability.

[0046] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A stent graft, characterized in that: include: The coated stent segment (100) comprises a stent body (110) in the form of a tubular network, and a tubular coating (120) disposed on the surface of the stent body (110); The bare stent segment (200) comprises a bare stent (210) connected to the two axial ends of the coated stent segment (100); the bare stent (210) is woven from a first metal wire in the shape of a spiral spring.

2. The stent graft according to claim 1, characterized in that: The bare stent (210) is provided with anti-proliferative drugs.

3. The stent graft according to claim 2, characterized in that: A concave hole (211) is provided on the first metal wire of the bare stent (210), and the anti-proliferation drug is arranged in the concave hole (211).

4. The stent graft according to claim 1, characterized in that: The bare stent (210) is spiral-shaped, and includes a plurality of first spiral turns formed by a single first metal wire spirally wrapped along the axial direction of the coated stent, and the first spiral turns have a plurality of first wave peaks (210a) and a plurality of first wave valleys (210b) alternately arranged in the circumferential direction.

5. The stent graft according to claim 1, characterized in that: Part of the first metal wire of the bare stent (210) is tilted outward relative to the outer circumference of the bare stent (210) to form an anchoring structure (220).

6. The stent graft according to any one of claims 1 to 5, characterized in that: A developing material layer is provided on the first metal wire of the bare bracket (210); or a developing ring is sleeved on the first metal wire of the bare bracket (210); or a developing wire (300) is provided in the internal space surrounded by the first metal wire of the bare bracket (210).

7. The stent graft according to claim 1, characterized in that: The stent body (110) is woven from a second metal wire in the shape of a spiral spring.

8. The stent graft according to claim 4, characterized in that: The stent body (110) is spiral-shaped and comprises a plurality of annular wave rings formed in sequence along the axial direction of the stent graft; the annular wave rings have a plurality of second wave peaks and a plurality of second wave valleys alternately arranged in the circumferential direction.

9. The stent graft according to claim 7, characterized in that: The first metal wire of the bare stent (210) is indirectly connected to the stent body (110) via the coating (120) or other connecting structures, or the first metal wire of the bare stent (210) and the second metal wire of the stent body (110) are the same metal wire formed in one piece.

10. The stent graft according to claim 9, characterized in that: The coating (120) is coated on the inner surface of the stent body (110), and / or the coating (120) is coated on the outer surface of the stent body (110).

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