Covered stent

Abstract

The invention discloses a covered stent, and relates to the technical field of interventional medical instruments, the covered stent is in a hollow tube shape, the covered stent comprises a covered stent section, the covered stent section comprises a stent, an outer covering film covering the outer surface of the stent, and an inner covering film covering the inner surface of the stent; an anti-hyperplasia drug is arranged on the stent, the outer covering film comprises one or more layers of porous films, the inner covering film comprises one or more layers of porous films, and the outer covering film and the inner covering film are suitable for delaying the release speed of the anti-hyperplasia drug on the stent. The anti-hyperplasia medicine is arranged on the stent body of the covered stent and in the area between the inner covering film and the outer covering film, and the inner covering film and the outer covering film have a certain blocking effect on medicine diffusion, so that the anti-hyperplasia medicine can be slowly released, and restenosis of blood vessels at the covered stent can be prevented.

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, since the stent graft is placed in the blood vessel for a long time as a foreign body, restenosis of the blood vessel still occurs at the stent graft. How to prevent restenosis of the blood vessel at the stent graft 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 at existing stent grafts are prone to restenosis.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows: A coated stent, the coated stent is in the shape of a hollow tube, the coated stent includes a coated stent segment, the coated stent segment includes a stent, an outer coating covered on the outer surface of the stent, and an inner coating covered on the inner surface of the stent; the stent is provided with an anti-proliferative drug, the outer coating includes one or more layers of porous films, the inner coating includes one or more layers of porous films, and the outer coating and the inner coating are suitable for delaying the release rate of the anti-proliferative drug on the stent.

[0006] By adopting the above technical solution, anti-proliferative drugs are arranged on the stent of the coated stent segment, and the inner and outer sides of the stent are respectively covered by an inner coating and an outer coating, and the inner coating and the outer coating both include one or more layers of porous films. Since the porous films have a certain barrier effect on the diffusion of anti-proliferative drugs, the anti-proliferative drugs can be slowly released, and the position of the blood vessel corresponding to the coated stent can be affected by the anti-proliferative drugs for a long time, tissue hyperplasia is not likely to occur, and the risk of restenosis of the blood vessel is reduced.

[0007] Furthermore, the stent graft segment includes a middle graft segment and end graft segments located at two axial ends of the middle graft segment, and the anti-proliferative drug content of the end graft segments is greater than that of the middle graft segment.

[0008] By adopting the above technical solution, since the axial end of the coated stent is relatively more prone to vascular restenosis, the probability of restenosis at the axial end of the coated stent can be reduced by designing the anti-proliferative drug content of the end coated segment to be higher.

[0009] Furthermore, anti-proliferative drugs are provided between the outer film and the inner film; and / or anti-proliferative drugs are provided between the multi-layer porous films of the outer film; and / or anti-proliferative drugs are provided between the multi-layer porous films of the inner film.

[0010] By adopting the above technical scheme, by additionally arranging anti-proliferative drugs in the area between the inner coating and the outer coating of the coated stent segment, or arranging anti-proliferative drugs between the multi-layer porous films of the outer coating, or arranging anti-proliferative drugs between the multi-layer porous films of the inner coating, compared with the method of coating the anti-proliferative drugs only on the stent surface or the outer surface of the coating in the existing coated stent, since there is a relatively larger drug storage space between the inner coating and the outer coating, between the multi-layer porous films of the outer coating, and between the multi-layer porous films of the inner coating, more anti-proliferative drugs can be stored in the coated stent segment, and the release period of the anti-proliferative drugs in the coated stent segment is longer, which can further reduce the risk of vascular restenosis.

[0011] Furthermore, the outer film and the inner film include a layer of porous film, and the pore size of the inner film itself is not larger than the pore size of the outer film itself.

[0012] By adopting the above technical solution, the voids in the outer and inner films facilitate the slow release of anti-proliferative drugs. In addition, since the blood vessel wall is a region where tissue hyperplasia occurs more easily due to foreign body rejection, the pore size of the inner film's voids is designed to be smaller, so that more anti-proliferative drugs can be preferentially released outward through the voids in the outer film and act on the tissues around the blood vessel wall, thereby reducing the risk of restenosis caused by tissue hyperplasia of the blood vessel wall.

[0013] Furthermore, the outer coating comprises a plurality of porous films stacked in sequence from the inside to the outside; in the direction from the stent to the outer coating, the pore size of each layer of the porous films of the outer coating gradually increases, and the content of anti-proliferative drugs between two adjacent layers of the porous films of the outer coating increases in sequence.

[0014] By adopting the above technical solution, the outer coating adopts a multi-layer porous film stacked from the inside to the outside. Compared with a single-layer porous film, the speed of anti-proliferative drugs being released through the outer coating can be further delayed. The position of the blood vessel wall corresponding to the coated stent can be affected by the anti-proliferative drugs for a long time, tissue hyperplasia is not likely to occur, and the risk of vascular restenosis is reduced.

[0015] Furthermore, the inner coating comprises a plurality of porous films stacked in sequence from the inside to the outside; in the direction from the stent to the inner coating, the pore size of each layer of the porous film of the inner coating gradually increases, and the content of anti-proliferative drugs between two adjacent layers of the porous film of the inner coating increases successively.

[0016] By adopting the above technical solution, the inner coating adopts a multi-layer porous film stacked from the inside to the outside. Compared with a single-layer porous film, the speed of anti-proliferative drugs being released outward through the inner coating can be further delayed. The blood in the blood vessel can be affected by the anti-proliferative drugs for a long time, is not easy to form thrombus, and reduces the risk of restenosis of the blood vessel.

[0017] Furthermore, the stent graft segment also includes a back metal piece fixed between two adjacent layers of porous films; the back metal piece is made of a developing material.

[0018] By adopting the above technical solution, the setting of the backing metal piece on the stent graft can limit the change of the length of the stent graft, so that the stent graft cannot be lengthened or shortened, which is conducive to the stent graft providing a suitable and stable support at the vascular lesion. The backing metal piece is made of a developing material, such as gold or platinum wire, so that the entire stent graft can be visualized during surgery.

[0019] Furthermore, the stent includes a plurality of circles of wavy rings, and the plurality of circles of wavy rings are arranged in parallel and at intervals along the axial direction of the coated stent.

[0020] By adopting the above technical solution, the uniformity of radial support force at various locations of the stent can be ensured, local stress concentration can be reduced, external pressure can be better resisted, and the risk of restenosis due to self-collapse of the coated stent segment in a narrowed or diseased blood vessel can be reduced.

[0021] Furthermore, the coated stent also includes a bare stent segment connected to both axial ends of the coated stent segment, and the bare stent segment is provided with an anti-proliferative drug; and the anti-proliferative drug content on the bare stent segment is greater than or equal to the anti-proliferative drug content on the coated stent segment.

[0022] By adopting the above technical scheme, since the axial edge of the coated stent segment is an area that is relatively more prone to vascular restenosis, the risk of vascular restenosis at the axial ends of the coated stent can be reduced by arranging bare stent segments with anti-proliferative drugs at both axial ends of the coated stent segment. At the same time, the bare stent segment can provide a better anchoring effect than the coated stent segment, thereby reducing the risk of displacement of the coated stent in the blood vessel and improving the treatment effect.

[0023] Furthermore, the bare stent segment includes a bare stent and a bare stent coating; the bare stent includes a bare stent uncoated segment having no coating on the surface and a bare stent coated segment having the bare stent coating on the surface, and the bare stent coated segment is located between the bare stent uncoated segment and the coated stent segment.

[0024] By adopting the above technical solution, since the stent portion covered by the membrane in the coated stent is usually located in the core area of ​​vascular diseased tissue, the relatively higher anti-proliferative drug content on the bare stent segment can effectively inhibit the proliferation of the tissue endothelium in this area and reduce the risk of vascular restenosis.

[0025] Furthermore, a developing material layer is provided on the uncoated section of the bare stent; or a developing ring is sleeved on the uncoated section of the bare stent.

[0026] By adopting the above technical solution, the setting of the developing material layer or the developing ring on the uncoated section of the bare stent can improve the visualization effect of the bare stent.

[0027] The technical solution of the present invention has the following advantages: by arranging anti-proliferative drugs on the stent of the coated stent and in the area between the inner coating and the outer coating, the inner coating and the outer coating have a certain barrier effect on the diffusion of the drugs, so that the anti-proliferative drugs can be slowly released, thereby preventing the blood vessels from restenosis at the coated stent. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 This is a schematic diagram of the structure of the stent graft in Embodiment 1 of the present invention; Figure 2 Schematic diagram of the positional relationship among the stent, the outer coating and the inner coating in the first embodiment of the present invention; Figure 3 This is a schematic diagram of the distribution of the anti-proliferative drug between the stent, the outer coating and the inner coating in Example 1 of the present invention; Figure 4 Schematic diagram of the positional relationship between the outer coating and the inner coating and the stent when both of them have three layers in the first embodiment of the present invention; Figure 5 This is a schematic structural diagram of a case where a back metal piece is provided on the membrane-covered support in the first embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the stent graft in the second embodiment of the present invention; Figure 7 Schematic diagram of the connection relationship between the covered stent segment and the bare stent segment in the second embodiment of the present invention; Figure 8 for Figure 7 Schematic diagram of the structure of the bare stent segment.

[0030] Explanation of the reference numerals: 100, coated stent segment; 110, stent; 111, wavy ring; 120, outer coating; 121, fourth layer of porous film; 122, fifth layer of porous film; 123, sixth layer of porous film; 130, inner coating; 131, first layer of porous film; 132, second layer of porous film; 133, third layer of porous film; 200, bare stent segment; 210, bare stent; 211, uncoated segment of bare stent; 212, coated segment of bare stent; 220, bare stent coating; 300, anti-proliferative drug; 400, developing ring; 500, back metal fitting. DETAILED DESCRIPTION

[0031] 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.

[0032] 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.

[0033] 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.

[0034] Embodiment 1 like Figure 1-Figure 3 A coated stent is shown, the coated stent includes a coated stent segment 100 that is in a hollow tubular shape as a whole. The coated stent segment 100 includes an outer coating 120, a stent 110, and an inner coating 130 that are arranged in sequence from the outside to the inside; the stent 110 is in a tubular network shape, the outer coating 120 is covered and fixed on the outer surface of the stent 110, and the inner coating 130 is covered and fixed on the inner surface of the stent 110; both the outer coating 120 and the inner coating 130 are in a tubular shape.

[0035] Among them, the materials of the inner coating 130 and the outer coating 120 can be polymer coatings such as expanded polytetrafluoroethylene film, polytetrafluoroethylene film, fluorinated ethylene propylene copolymer film, silicone film, etc. The barrier effect of the outer coating 120 on the vascular wall tissue can prevent the excessive proliferation of 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 inner coating 130 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 inner coating 130 can reduce intimal hyperplasia, reduce the risk of thrombosis, and prolong the patency time of the coated stent. The stent 110 can be a metal stent such as nickel-titanium alloy, stainless steel alloy, cobalt-chromium alloy, magnesium alloy and other metal materials with good biocompatibility, or it can be all non-metallic stents, such as poly (lactic-co-glycolic acid) copolymer (PLGA) and other non-metallic materials with good biocompatibility.

[0036] In some embodiments, the stent 110 is provided with an anti-proliferative drug 300, which includes but is not limited to any one or more of heparin, rapamycin and its derivatives, paclitaxel and its derivatives. Since the inner coating 130 and the outer coating 120 have a certain blocking effect on the diffusion of the anti-proliferative drug 300, the anti-proliferative drug 300 can be slowly released, and the position of the blood vessel corresponding to the coated stent can be affected by the anti-proliferative drug 300 for a long time, and tissue hyperplasia is not likely to occur, thereby reducing the risk of restenosis of the blood vessel.

[0037] Specifically, the coated stent segment 100 includes a middle coated segment and end coated segments located at both axial ends of the middle coated segment, and the content of anti-proliferative drug 300 in the end coated segments is greater than that in the middle coated segment. Since the coated stent segment 100 has a greater stimulation to the contacting blood vessel wall at the axial end, it is easy to cause intimal hyperplasia at the contact point, which leads to the axial end of the coated stent segment 100 being easily narrowed, so the axial end of the coated stent segment 100 is a relatively more prone to vascular restenosis. By arranging a higher content of anti-proliferative drug 300 on the end coated segments, the axial proliferation of the intimal tissue in the core area of ​​vascular lesions along the coated stent segment 100 can be better inhibited, the probability of restenosis at the axial end of the coated stent segment 100 can be reduced, and the service life of the coated stent can be increased.

[0038] like Figure 3 As shown, in other embodiments, the coated stent segment 100 is provided with anti-proliferative drugs 300 not only on the stent 110, but also in the region between the outer coating 120 and the inner coating 130. When the outer coating 120 and the inner coating 130 include multiple layers of porous films, the anti-proliferative drugs 300 are provided between two adjacent layers of the porous films of the outer coating 120, and the anti-proliferative drugs 300 are provided between two adjacent layers of the porous films of the inner coating 130. By additionally arranging anti-proliferative drugs 300 in the area between the inner coating 130 and the outer coating 120 of the coated stent segment 100, or additionally arranging anti-proliferative drugs 300 between the multi-layer porous films of the outer coating 120, or additionally arranging anti-proliferative drugs 300 between the multi-layer porous films of the inner coating 130, compared with the method of coating the anti-proliferative drugs only on the stent surface or the outer surface of the coating in the existing coated stent, since there is a relatively larger drug storage space between the inner coating 130 and the outer coating 120, between the multi-layer porous films of the outer coating 120, and between the multi-layer porous films of the inner coating 130, more anti-proliferative drugs 300 can be stored in the coated stent segment 100, and the release period of the anti-proliferative drugs 300 in the coated stent segment 100 is longer, which can further reduce the risk of vascular restenosis.

[0039] In some embodiments, the outer film 120 and the inner film 130 are both porous films made of porous materials, the outer film 120 includes one or more layers of porous films, and the inner film 130 includes one or more layers of porous films. Since the porous film has a certain barrier effect on the diffusion of anti-proliferative drugs, the anti-proliferative drugs can be slowly released, and the position of the blood vessel corresponding to the coated stent can be affected by the anti-proliferative drugs for a long time, and tissue hyperplasia is not likely to occur, thereby reducing the risk of vascular restenosis. When the outer film 120 includes a layer of porous film and the inner film 130 also includes a layer of porous film, the pore size of the inner film 130 itself is not larger than the pore size of the outer film 120 itself; since the blood vessel wall is more likely to have intimal tissue hyperplasia due to foreign body rejection, the pore size of the inner film 130 itself is designed to be smaller, so that more anti-proliferative drugs can be preferentially released outward through the pores of the outer film 120 itself and act on the intimal tissue around the blood vessel wall, thereby reducing the risk of vascular restenosis caused by intimal tissue hyperplasia.

[0040] like Figure 4 As shown, in other embodiments, the outer film 120 includes multiple porous films stacked sequentially from the inside to the outside, and the inner film 130 includes multiple porous films stacked sequentially from the inside to the outside. For example; in the direction from the support 110 to the inner film 130, the inner film 130 includes a first porous film 131, a second porous film 132, and a third porous film 133 stacked sequentially; in the direction from the support 110 to the outer film 120, the outer film 120 includes a fourth porous film 121, a fifth porous film 122, and a sixth porous film 123 stacked sequentially; of course, the number of porous film layers included in the outer film 120 and the number of porous film layers included in the inner film 130 are not limited to three layers, and can also be two layers or four layers or more. Compared with a single-layer porous film, the outer film 120 and the inner film 130 configured in this way can further slow down the speed at which the anti-proliferative drugs are released outward through the outer film 120 or the inner film 130. The position of the blood vessel wall corresponding to the coated stent can be affected by the anti-proliferative drugs for a long time, and tissue hyperplasia is not likely to occur. The blood in the blood vessel can also be affected by the anti-proliferative drugs for a long time, and thrombus formation is not likely to occur, thereby reducing the risk of restenosis of the blood vessel.

[0041] Further, in the direction from the stent 110 to the inner film 130, the pore size of the interstices of each layer of the porous film of the inner film 130 gradually increases, and the content of anti-proliferative drugs between two adjacent layers of the porous film of the inner film 130 increases successively. In the direction from the stent 110 to the outer film 120, the pore size of the interstices of each layer of the porous film of the outer film 120 gradually increases, and the content of anti-proliferative drugs between two adjacent layers of the porous film of the outer film 120 increases successively. Specifically, the pore size of the internal pores of the first porous film 131, the second porous film 132 and the third porous film 133 increases successively, and the content of drugs between two adjacent layers of porous films increases successively. The pore size of the internal pores of the fourth porous film 121, the fifth porous film 122 and the sixth porous film 123 increases successively, and the content of drugs between two adjacent layers of porous films increases successively. Such a configuration can further slow down the speed at which the anti-proliferative drug is released outward through the outer film 120 or the inner film 130 .

[0042] like Figure 5 As shown, in some embodiments, the stent graft further includes a back metal piece 500 fixed between two adjacent layers of porous films; the back metal piece 500 is made of a developing material. The back metal piece 500 can be fixed between the multiple layers of porous films by hot melting or the like. The function of the back metal piece 500 is to limit the change in the length of the stent graft so that the stent graft cannot become longer or shorter, which is beneficial for the stent graft to provide a suitable and stable support at the vascular lesion. The back metal piece 500 is made of a developing material such as gold or platinum wire, which can make the entire stent graft visible during surgery.

[0043] like Figure 1 As shown, in some embodiments, the stent 110 includes a plurality of circles of wavy rings 111, and the plurality of circles of wavy rings 111 are arranged in parallel and spaced relation along the axial direction of the stent graft. Each wavy ring 111 is wound by a metal wire, and a plurality of wavy rings 111 are connected as a whole through an inner coating 130 and an outer coating 120. The wavy ring 111 has a plurality of crests and a plurality of troughs arranged alternately in the circumferential direction. The crests of two adjacent circles of wavy rings 111 are arranged in corresponding positions in the axial direction of the stent graft segment 100, and the troughs of two adjacent circles of wavy rings 111 are also arranged in corresponding positions in the axial direction of the stent graft. This stent graft segment 100 can ensure the uniformity of radial support force at various locations, reduce local stress concentration, better resist external pressure, and reduce the risk of restenosis of the stent graft segment 100 due to self-collapse in a narrow or diseased blood vessel. In other alternative embodiments, the stent 110 can also be wound by a single metal wire spiral.

[0044] Embodiment 2 like Figure 6 and Figure 7A coated stent is shown, the coated stent is in the shape of a hollow tube as a whole, and the coated stent includes a coated stent segment 100 and two bare stent segments 200 connected to the axial ends of the coated stent segment 100. Anti-proliferative drugs are provided on the bare stent segment 200. Since the axial edge of the coated stent segment 100 is a region that is relatively more prone to vascular restenosis, by providing the bare stent segment 200 with anti-proliferative drugs at the axial ends of the coated stent segment 100, the risk of vascular restenosis at the axial end of the coated stent can be reduced; at the same time, the bare stent segment 200 can provide a better anchoring effect relative to the coated stent segment 100, reduce the risk of displacement of the coated stent in the blood vessel, and improve the treatment effect.

[0045] The structure of the coated stent segment 100 is the same as that of the coated stent segment 100 in the first embodiment, which will not be described in detail here. The specific structure of the bare stent segment 200 is described in detail below. Figure 6 and Figure 7 As shown, the bare stent segment 200 includes a bare stent 210 and a bare stent coating 220; the bare stent 210 includes a bare stent uncoated segment 211 having no coating on the surface and a bare stent coated segment 212 having a bare stent coating 220 on the surface, and the bare stent coated segment 212 is located between the bare stent uncoated segment 211 and the coated stent segment 100. The bare stent coating 220 may be a portion of the inner coating 130 and the outer coating 120 extending to the inner surface of the bare stent 210 or the outer surface of the bare stent 210, and the bare stent coating 220 may also be a coating separately arranged on the inner and outer surfaces of the bare stent coated segment 212.

[0046] In some embodiments, the content of anti-proliferative drugs on the bare stent segment 200 is greater than or equal to the content of anti-proliferative drugs on the covered stent segment 100. Since the bare stent segment 200 has a greater stimulation to the contacting blood vessel wall and is likely to cause intimal hyperplasia at the contacting part, the bare stent segment 200 is a location on the covered stent that is relatively more prone to vascular restenosis; by providing a higher content of anti-proliferative drugs on the bare stent segment 200, the probability of restenosis of the bare stent segment 200 can be better suppressed, thereby increasing the service life of the covered stent.

[0047] See also Figure 6 In some embodiments, a developing ring 400 is sleeved on the bare stent uncoated section 211; or a developing material layer is provided on the bare stent uncoated section 211. The provision of the developing ring or the developing material layer can improve the visualization effect of the bare stent 210. The materials of the developing ring or the developing material layer include but are not limited to gold, platinum, tantalum, osmium, rhenium, tungsten, iridium, rhodium and the like or alloys or composites of these metals.

[0048] See also Figure 6 , Figure 7 and Figure 8The bare stent 210 is spiral-shaped, and includes a plurality of spiral coils formed by a single metal wire spirally wound along the axial direction of the coated stent, and the spiral coils have a plurality of crests and a plurality of troughs alternately arranged in the circumferential direction. The crests on two adjacent spiral coils are arranged in a corresponding position, and the troughs on two adjacent spiral coils are also arranged in a corresponding position.

[0049] In summary, the coated stent provided in the embodiment of the present invention sets the anti-proliferative drug 300 on the stent 110 of the coated stent and in the area between the inner coating 130 and the outer coating 120. Since the inner coating 130 and the outer coating 120 have a certain blocking effect on the diffusion of the anti-proliferative drug 300, the anti-proliferative drug 300 can be slowly released to prevent restenosis of the blood vessel at the coated stent.

[0050] 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: The coated stent is in the shape of a hollow tube, and the coated stent comprises a coated stent segment (100), and the coated stent segment (100) comprises a stent (110), an outer coating (120) covering the outer surface of the stent (110), and an inner coating (130) covering the inner surface of the stent (110); the material of the inner coating (130) and the outer coating (120) is any one of expanded polytetrafluoroethylene film, polytetrafluoroethylene film, fluorinated ethylene propylene copolymer film, and silicone film; the stent (110) is provided with an anti-proliferative The drug (300) is provided, wherein the outer film (120) comprises a plurality of porous films, and the inner film (130) comprises a plurality of porous films, and the outer film (120) and the inner film (130) are suitable for delaying the release rate of the anti-proliferative drug on the stent (110); in a direction from the stent (110) to the outer film (120), the pore size of each layer of the porous film of the outer film (120) gradually increases, and the content of the anti-proliferative drug between two adjacent layers of the porous film of the outer film (120) increases successively; The stent graft segment (100) further comprises a back metal piece fixed between two adjacent layers of porous films; the back metal piece is made of a developing material; The coated stent also includes a bare stent segment (200) connected to the two axial ends of the coated stent segment (100), and the bare stent segment (200) is provided with an anti-proliferative drug; and the content of the anti-proliferative drug on the bare stent segment (200) is greater than the content of the anti-proliferative drug on the coated stent segment (100).

2. The stent graft according to claim 1, characterized in that: The coated stent segment (100) comprises a middle coated segment and end coated segments located at two axial ends of the middle coated segment, and the anti-proliferative drug content of the end coated segments is greater than the anti-proliferative drug content of the middle coated segment.

3. The stent graft according to claim 1, characterized in that: An anti-proliferative drug (300) is provided between the outer film (120) and the inner film (130); and / or an anti-proliferative drug (300) is provided between the multiple porous films of the outer film (120); and / or an anti-proliferative drug (300) is provided between the multiple porous films of the inner film (130).

4. The stent graft according to claim 1, characterized in that: The pore size of the inner coating (130) itself is not greater than the pore size of the outer coating (120) itself.

5. The stent graft according to claim 1, characterized in that: The inner coating (130) comprises multiple layers of porous films stacked in sequence from the inside to the outside; in the direction from the stent (110) to the inner coating (130), the pore size of the gaps in each layer of the porous films of the inner coating (130) gradually increases, and the content of anti-proliferative drugs between two adjacent layers of the porous films of the inner coating (130) increases in sequence.

6. The stent graft according to claim 1, characterized in that: The bare stent segment (200) includes a bare stent (210) and a bare stent coating (220); the bare stent (210) includes a bare stent uncoated segment (211) having no coating on the surface and a bare stent coated segment (212) having the bare stent coating (220) on the surface, and the bare stent coated segment (212) is located between the bare stent uncoated segment (211) and the coated stent segment (100).

7. The stent graft according to claim 1, characterized in that: A developing material layer is provided on the uncoated section (211) of the bare stent; or a developing ring (400) is sleeved on the uncoated section (211) of the bare stent.

Images