Covered stent and manufacturing method thereof

Abstract

The present invention provides a covered stent and a manufacturing method thereof, which are applied to the field of implantable medical devices. The covered stent includes a framework, a framework covering film, and an inner covering film. The framework covering film is disposed on the framework, and the framework covering film and the framework are adhesively bonded together. The inner covering film is disposed in the inner cavity of the covered stent surrounded by the framework covering film and the framework. The inner covering film includes N adhesive segments and M separated segments, where N≥2 and M = N - 1. The adhesive segments and the separated segments are alternately arranged at intervals along the axial direction of the framework covering film and are connected into one body. The adhesive segments are respectively adhesively bonded to the framework covering film and the framework, and a hollow layer is formed between the separated segments and the framework covering film. By adding an inner covering film in the inner cavity of a common covered stent, the inner wall of the covered stent can be made smooth.

Description

Technical Field

[0001] The present invention relates to the field of implantable medical devices, and in particular to a stent graft and a method for manufacturing the stent graft. Background Art

[0002] In the field of implantable medical devices, ePTFE coated stents have been widely recognized in recent years. Their advantages include excellent biocompatibility and super-lubricity. The indications for this type of coated stents include peripheral vascular embolism, aortic and branch dissections, true aortic aneurysms of the aorta and branches, false aneurysms of the aorta and branches, and penetrating ulcers of the aorta and branches. The implantation surgery using this type of coated stent greatly reduces the surgical mortality rate and postoperative complications, while reducing surgical trauma and allowing patients to recover faster. The mechanism of this implantation surgery is to deliver the coated stent to the lesion site through a special delivery system and then open it, thereby opening the blood vessels blocked by thrombus or isolating the tumor from the blood, reducing the risk of death due to massive bleeding from aneurysm rupture, or reducing the pressure of the tumor on surrounding tissues and organs.

[0003] In the field of peripheral blood vessels, most lesions are vascular embolism. The diameter of the target blood vessel is small, generally less than 10 mm, and the anatomical morphology is tortuous. The stent graft needs to have high flexibility. The so-called flexibility means that the shape of the stent graft can adapt to the shape of the blood vessel and change with the change of the blood vessel shape. Good flexibility can make the stent graft adhere well to the blood vessel wall, and there will be no gap between the outer wall of the stent graft and the blood vessel.

[0004] However, when the coated stent is highly flexible, the coating is easily affected by the deformation of the skeleton and wrinkles are formed. Specifically, the high flexibility of the coated stent allows the skeleton to produce corresponding deformation as the thrombus in the blood vessel bulges, so that the outer wall of the skeleton can better fit the diseased blood vessel, but this also causes the coating in the coated stent to wrinkle, and the inner lumen of the coated stent is no longer smooth, but irregular. The irregular shape of the inner lumen of the coated stent is likely to change the blood flow in the lumen of the blood vessel, such as generating vortices in the blood vessel. And the change in the blood flow in the lumen of the blood vessel is likely to cause thrombus formation in the inner lumen of the coated stent, causing restenosis in the coated stent. In the clinical application of coated stents, the problem of restenosis of coated stents has always been the focus of clinical research.

[0005] Therefore, there is an urgent need to improve the existing coated stent to make the inner cavity of the coated stent smooth. Summary of the invention

[0006] The object of the present invention is to provide a stent graft and a method for manufacturing the stent graft, so as to solve the problem that the inner cavity of the existing stent graft is not smooth.

[0007] To solve the above technical problems, the present invention provides a covered stent, comprising a framework, a framework covering film, and an inner covering film. The framework covering film is disposed on the entire framework, and the framework covering film and the framework are adhesively bonded to each other. The inner covering film is disposed in the inner cavity of the covered stent. The inner covering film includes N bonding segments and M separating segments, where N≥2 and M = N - 1. The bonding segments and the separating segments are alternately arranged along the axial direction of the framework covering film and are connected into one body. The bonding segments are adhesively bonded to the framework covering film, and a hollow layer is formed between the separating segments and the framework covering film.

[0008] Optionally, the inner covering film covers the entire inner cavity of the covered stent.

[0009] Optionally, the axial length of the inner covering film is less than the axial length of the covered stent, and both ends of the inner covering film do not coincide with both ends of the covered stent.

[0010] Optionally, the number of the bonding segments N = 2, and the number of the separating segments M = 1.

[0011] Optionally, the number of the bonding segments N≥3.

[0012] Optionally, the framework covering film includes an outer covering film and a middle covering film. The outer covering film is disposed on the entire outer peripheral surface of the framework, the middle covering film is disposed on the entire inner peripheral surface of the framework, and the outer covering film, the middle covering film, and the framework are adhesively bonded to each other pairwise.

[0013] Optionally, the framework is disposed in the film layer of the framework covering film.

[0014] Optionally, the framework covering film includes an outer covering film. The outer covering film is disposed on the entire outer peripheral surface of the framework, and the outer covering film and the framework are adhesively bonded to each other.

[0015] Optionally, the inner covering film is a PU film, a UHMWPE film, a PTFE film, or an ePTFE film.

[0016] The present invention also provides a manufacturing method of the above covered stent. The covered stent includes a framework, a framework covering film, and an inner covering film. The inner covering film includes N bonding segments and M separating segments, where N≥2 and M = N - 1. One bonding segment is disposed at each of both ends of the inner covering film. The bonding segments and the separating segments are alternately arranged along the axial direction of the framework covering film. The manufacturing method of the covered stent includes: disposing the framework covering film on the framework and adhesively bonding the framework covering film and the framework to each other; and disposing the inner covering film in the inner cavity of the covered stent and adhesively bonding the bonding segments to the framework covering film.

[0017] The present invention provides a covered stent and a manufacturing method thereof, which have the following beneficial effects:

[0018] Since the skeleton covering film is connected to the skeleton, when the shape of the skeleton changes, the shape of the skeleton covering film constrained by the skeleton will also change with the change of the shape of the skeleton. The inner covering film is arranged in the inner cavity surrounded by the covered stent, and the bonding sections at both ends of the inner covering film are bonded to the skeleton covering film and the skeleton. Among them, the bonding sections at both ends of the inner covering film are also bonded to the skeleton covering film and the skeleton, and the separating section of the inner covering film and the middle covering film enclose a hollow layer. At the same time, the bonding sections and the separating sections are arranged alternately along the axial direction of the skeleton covering film, and the bonding sections and the separating sections are connected in sequence to form a whole. Therefore, the separating section of the inner covering film and the middle covering film are separated from each other. Thus, the separating section of the inner covering film is not constrained by the skeleton. When the shape of the skeleton changes, since the inner covering film is not completely constrained by the skeleton, the shape of the inner covering film will not change with the change of the shape of the skeleton, that is, the inner covering film is not easily wrinkled under the influence of the skeleton, but will form a relatively smooth transition between the fixed end (the bonding place of the inner covering film with the outer covering film, the middle covering film and the skeleton) and the stress point (the stress application point of the skeleton on the inner covering film), making the shape in the cavity closer to a circular tube shape, thereby reducing the risk of restenosis of the covered stent caused by the wrinkles on the inner wall of the covered stent after it is implanted into the blood vessel. Especially when the covered stent is implanted into the blood vessel, under the scouring of the blood flow, the inner wall of the inner covering film can still remain smooth, or the wrinkles formed on the inner wall of the inner covering film due to the bending and folding of the skeleton can be reduced or eliminated. Description of the Drawings

[0019] Figure 1 is a cross-sectional view of the covered stent in Embodiment 1 of the present invention;

[0020] Figure 2 is a schematic cross-sectional view of the covered stent after bending in Embodiment 1 of the present invention;

[0021] Figure 3 is a schematic diagram of the covered stent of an embodiment of the present invention implanted into the blood vessel but not released;

[0022] Figure 4 is a schematic diagram of the covered stent of an embodiment of the present invention implanted into the blood vessel and released;

[0023] Figure 5 is a cross-sectional view of the covered stent in Embodiment 2 of the present invention;

[0024] Figure 6 is a cross-sectional view of the covered stent in Embodiment 3 of the present invention;

[0025] Figure 7 It is a cross-sectional view of the covered stent in the fifth embodiment of the present invention.

[0026] Description of the reference numerals:

[0027] 100 - covered stent; 110 - framework; 120 - framework covering; 121 - outer covering; 122 - middle covering; 130 - inner covering; 131 - bonding section; 132 - separation section; 140 - hollow layer; 150 - stress point; 160 - blood vessel. Detailed implementation manners

[0028] As described in the background art, the existing covered stents have the problem of uneven inner cavities. Based on this, the present application proposes a covered stent and a manufacturing method thereof. On the basis of a common covered stent, an artificial blood vessel is added to the inner cavity of the covered stent, that is, a layer of covering is added to the inner cavity of the covered stent. Both ends of this layer of covering are fixed to the original covered stent, and the middle part is separated from the original covered stent, similar to an artificial blood vessel. Since the added layer of covering is separated from the original covered stent, when the original covered stent generates wrinkles due to the bending of the framework, the added layer of covering will not generate wrinkles accordingly. Instead, a relatively smooth transition will be formed between the fixed points at both ends of the added layer of covering and the stress points in the middle, making the shape of the covered stent closer to a circular tube and making the inner wall of the covered stent smooth.

[0029] The following further details the covered stent and the manufacturing method thereof proposed by the present invention with reference to the drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the embodiments of the present invention.

[0030] Embodiment 1

[0031] This embodiment provides a covered stent. Figure 1 It is a cross-sectional view of the covered stent in the first embodiment of the present invention. Refer to Figure 1, the covered stent 100 includes a framework 110, a framework covering 120, and an inner covering 130. The framework covering 120 includes an outer covering 121 and a middle covering 122. The outer covering 121 is disposed on the entire outer peripheral surface of the framework 110, the middle covering 122 is disposed on the entire inner peripheral surface of the framework 110, and the outer covering 121, the middle covering 122, and the framework 110 are adhesively bonded to each other pairwise. The inner covering 130 is disposed in the inner cavity of the covered stent 100. Specifically, the inner covering 130 is disposed on the entire inner wall of the middle covering 122. The inner covering 130 includes N adhesive segments 131 and M separated segments 132. In this embodiment, N = 2 and M = N - 1. One adhesive segment 131 is disposed at each end of the inner covering 130. The adhesive segments 131 and the separated segments 132 are alternately arranged along the axial direction of the framework covering 120, and the adhesive segments 131 and the separated segments 132 are connected in sequence to form a whole. The adhesive segments 131 at both ends of the inner covering 130 are adhesively bonded to the middle covering 122. The part of the inner covering 130 that is not adhesively bonded to the middle covering 122 and the middle covering 122 together enclose a hollow layer 140, that is, the separated segments 132 of the inner covering 130 and the middle covering 122 together enclose a hollow layer 140. That is to say, in this embodiment, the adhesive segments 131 are disposed at both ends of the inner covering 130, and the separated segments 132 are located in the middle of the inner covering 130.

[0032] In this embodiment, since the outer layer film 121 disposed on the entire outer peripheral surface of the framework 110 and the middle layer film 122 disposed on the entire inner peripheral surface of the framework 110 are connected to the framework 110 in pairs, when the shape of the framework 110 changes, the shapes of the outer layer film 121 and the middle layer film 122 constrained by the framework 110 will also change with the change in the shape of the framework 110. The inner layer film 130 is disposed in the inner cavity surrounded by the middle layer film 122. The bonding sections 131 at both ends of the inner layer film 130 are respectively bonded to the middle layer film 122, and a hollow layer 140 is formed by the separation section 132 of the inner layer film 130 and the middle layer film 122. Therefore, the separation section 132 of the inner layer film 130 and the middle layer film 122 are separated from each other, and thus the separation section 132 of the inner layer film 130 is not constrained by the framework 110. Therefore, when the shape of the framework 110 changes, since the inner layer film 130 is not completely constrained by the framework 110, the shape of the inner layer film 130 will not change with the change in the shape of the framework 110, that is, the inner layer film 130 is not likely to form wrinkles under the influence of the framework 110, but rather a relatively smooth transition will be formed between the fixed end (the bonding position of the inner layer film 130 and the middle layer film 122, that is, the two bonding sections 131 in this embodiment) and the force application point (the force application point of the framework 110 on the inner layer film 130), making the shape of the cavity closer to a circular tube shape. Especially when the covered stent 100 is implanted into a blood vessel, under the scouring of blood flow, the inner wall of the inner layer film 130 can still remain smooth, or the wrinkles formed on the inner wall of the inner layer film 130 due to the bending and folding of the framework 110 can be reduced or eliminated. Thereby, the risk of restenosis of the covered stent 100 caused by the wrinkles on the inner wall of the covered stent 100 after being implanted into the blood vessel can be reduced.

[0033] Figure 2 is a schematic cross-sectional view of the covered stent 100 in the first embodiment of the present invention after bending, as Figure 2 shown, when the shape of the framework 110 changes, since the inner layer film 130 is not completely constrained by the framework 110, the shape of the inner layer film 130 will not change with the change in the shape of the framework 110, but rather a relatively smooth transition will be formed between the fixed end (i.e., the bonding section 131) and the force application point 150, making the shape of the cavity closer to a circular tube shape.

[0034] An existing covered stent with good flexibility and no obvious wrinkles in the inner cavity reduces the influence of the stent on the shape of the covering film during bending by exposing the stent vertices, thereby reducing the risk of restenosis of the covered stent. However, this covered stent can only use the net-shaped restraint delivery system invented for it and cannot be compatible with the delivery systems currently on the market. In addition, the stent in this covered stent is exposed, and the direct contact between the stent and the blood vessel wall is likely to cause an inflammatory reaction. Moreover, the technical difficulty of implementing this net-shaped restraint delivery system is relatively high. Special materials and corresponding machines are required to weave the corresponding net, and the cost of this delivery system is relatively high. Compared with this covered stent, the covered stent in this embodiment does not change the original stent 110 of the covered stent, but only sets an inner covering film 130 in the inner cavity of the stent 110. Therefore, no special delivery system is required for installation, and it has good compatibility with common delivery systems. In addition, the stent 110 of the covered stent 100 in this embodiment is not exposed, so the inflammatory reaction caused by the exposure of the stent 110 can be avoided. Furthermore, the inner wall of the inner covering film 130 in the covered stent 100 in this embodiment can be kept smooth. Therefore, while the covered stent 100 has good flexibility, its inner wall can also be kept smooth.

[0035] The covered stent 100 is easy to implement, and improves the practicability of the covered stent 100, which helps to promote the application of the covered stent 100 in the field of implantable medical devices. The application range of the covered stent 100 can include all large thoracic and abdominal aortic stents, as well as small stents for arterial branches and peripherals.

[0036] The structure of the covered stent 100 is simple, easy to operate, and does not require additional costs. Compared with the covered stents 100 on the market, the covered stent 100 in this embodiment maximally retains the characteristic of the smooth inner cavity shape of the covered stent 100.

[0037] The stent 110 in the covered stent 100 can be a corrugated stent made of metal NiTi wire or pure titanium wire. The material of the stent 110 can also be stainless steel, cobalt-chromium alloy, nickel-titanium alloy, etc.

[0038] The outer covering film 121, the middle covering film 122, and the inner covering film 130 can be PU (polyurethane) film, UHMWPE (ultra-high molecular weight polyethylene) film, PTFE (Polytetrafluoroethylene) film, or ePTFE (expanded Polytetrafluoroethylene) film.

[0039] This embodiment also provides a manufacturing method of the covered stent 100, which is specifically as follows:

[0040] First, the outer layer film 121 is disposed on the entire outer peripheral surface of the frame 110 (which can be a corrugated frame 110 made of NiTi wire), and the middle layer film 122 is disposed on the entire inner peripheral surface of the frame 110. At the same time, the outer layer film 121, the middle layer film 122 and the frame 110 are adhesively bonded to each other to fabricate a complete double-layer film stent.

[0041] Secondly, an inner layer film 130 is disposed in the inner cavity formed by the middle layer film 122, such that the inner layer film 130 is disposed on the entire inner wall of the middle layer film 122, and the two bonding segments 131 of the inner layer film 130 are respectively adhesively bonded to the middle layer film 122, thereby forming a three-layer film stent 100. For example, when the length of the film stent 100 is 100 mm and the diameter is 10 mm, the length of the bonding segment 131 is 5 mm, and the length of the separation segment 132 is 90 mm. Wherein, the length of the bonding segment 131 refers to the length of the bonding segment 131 along the axial direction of the film stent 100, which is also the length of the bonding segment 131 along the axial direction of the frame 110, and is also the length of the bonding segment 131 along the axial direction of the frame film 120. Of course, the above dimensions are only for example and do not limit the technical solution of the present invention.

[0042] Generally, after the film stent 100 is fabricated, it is installed in a conveyor, and then the film stent 100 is implanted into the blood vessel 160 through a delivery system.

[0043] Figure 3 It is a schematic diagram of the film stent in an embodiment of the present invention implanted in a blood vessel but not released. Figure 4 It is a schematic diagram of the film stent in an embodiment of the present invention after being released after being implanted in a blood vessel. Refer to Figure 3 and Figure 4 , after the film stent 100 is implanted into the blood vessel 160, the stenosed blood vessel 160 is expanded, thereby achieving the effect of curing the stenosis of the blood vessel 160. However, the blood vessel wall expanded by the stent cannot be completely flat, and plaques and thrombi will still slightly bulge. The high flexibility of the stent enables the metal frame to deform accordingly with the bulge of the thrombus, so that the outer wall of the stent better fits the diseased blood vessel. At the same time, the structural design of the three-layer film stent 100 ensures the smoothness of the inner cavity of the stent, so that the blood flow flows smoothly therein.

[0044] Embodiment Two

[0045] This embodiment provides a film stent. The difference between the film stent in this embodiment and the film stent in Embodiment One is that the number N of the bonding segments in this embodiment is N≥3. The multiple separation segments and the middle layer film enclose multiple hollow layers, and the multiple hollow layers are alternately arranged along the axial direction of the frame.

[0046] Figure 5 is a cross-sectional view of the covered stent in the second embodiment of the present invention. Refer to Figure 5 , a plurality of bonding segments 131 of the inner layer film 130 are respectively bonded to the middle layer film 122, and a plurality of the separation segments 132 and the middle layer film 122 enclose a plurality of hollow layers 140, and the plurality of hollow layers 140 are alternately arranged along the axial direction of the framework 110.

[0047] Since the inner layer film 130 is relatively soft and cannot be bent and formed by itself, the inner layer film 130 and the middle layer film 122 are adhesively bonded to each other in multiple alternating segments in the area far from the proximal end and the distal end, which can make the inner layer film 130 more firmly bonded, and can better conform to the bending shape of the framework 110 when the framework 110 is bent. Since there are still multiple segments where the inner layer film 130 and the middle layer film 122 are not adhesively bonded to each other, the inner layer film 130 can still reduce or eliminate the problem of wrinkles generated on the inner wall of the inner layer film 130 due to the bending of the framework 110.

[0048] This embodiment also provides a manufacturing method of the covered stent 100, which is as follows:

[0049] First, the outer layer film 121 is disposed on the entire outer peripheral surface of the framework 110 (which can be a corrugated framework 110 made of NiTi wire), and the middle layer film 122 is disposed on the entire inner peripheral surface of the framework 110. At the same time, the outer layer film 121, the middle layer film 122 and the framework 110 are adhesively bonded to each other to manufacture a complete double-layer stent.

[0050] Secondly, the inner layer film 130 is disposed in the inner cavity formed by the middle layer film 122, so that the inner layer film 130 is disposed on the entire inner wall of the middle layer film 122, and the bonding segments 131 of the inner layer film 130 are bonded to the middle layer film 122, thereby forming a three-layer covered stent 100. For example, when the length of the covered stent 100 is 114 mm and the diameter is 10 mm, the length of the bonding segments 131 disposed at both ends of the inner layer film 130 is 5 mm, the length of the bonding segments 131 disposed between both ends of the inner layer film 130 is 1 mm, and the distance between two adjacent bonding segments 131 is 20 mm. Wherein, the length of the bonding segment 131 refers to the length of the bonding segment 131 along the axial direction of the covered stent 100, and also refers to the length of the bonding segment 131 along the axial direction of the framework 110, and also refers to the length of the bonding segment 131 along the axial direction of the framework film 120. Of course, the above dimensions are only for example and do not limit the technical solution of the present invention.

[0051] Embodiment Three

[0052] This embodiment provides a covered stent. Figure 6It is a cross-sectional view of the covered stent in the third embodiment of the present invention. Refer to Figure 6 , the difference between the covered stent 100 in this embodiment and the covered stent 100 in the first embodiment is that in this embodiment, the inner layer film 130 is arranged on the region of the framework 110 that is far from the proximal end of the framework 110 and far from the distal end of the framework 110, that is, the axial length of the inner layer film 130 is less than the length of the covered stent 100, and both ends of the inner layer film 130 do not coincide with the two ends of the covered stent 100, and the bonding sections 131 at both ends of the inner layer film 130 are respectively bonded to the middle layer film 122, and the separated section 132 of the inner layer film 130 and the middle layer film 122 enclose a hollow layer 140 together.

[0053] In this embodiment, the inner layer film 130 is not arranged on the inner wall of the entire middle layer film 122, which can reduce the problem that the volume of the covered stent 100 increases (the outer diameter increases after crimping) caused by the setting of the inner layer film 130. At the same time, the inner layer film 130 can be used on the inner wall of the middle layer film 122, and only the bonding sections 131 at both ends of the inner layer film 130 are bonded to the middle layer film 122, while the separated section 132 of the inner layer film 130 is separated from the inner wall of the middle layer film 122, so as to eliminate or reduce the risk of the inner layer film 130 forming wrinkles under the action of the deformation of the framework 110, so that the inner wall of the covered stent 100 can be kept smooth.

[0054] This embodiment also provides a manufacturing method of the covered stent 100, which is as follows:

[0055] First, the outer layer film 121 is arranged on the entire outer peripheral surface of the framework 110 (which can be a corrugated framework 110 made of NiTi wire), and the middle layer film 122 is arranged on the entire inner peripheral surface of the framework 110, and at the same time, the outer layer film 121, the middle layer film 122 and the framework 110 are bonded to each other in pairs to manufacture a complete double-layer stent.

[0056] Secondly, an inner layer film 130 is disposed in the inner cavity formed by the middle layer film 122, and is only disposed in the area that is away from the proximal end and the distal end of the middle layer film 122. The bonding segments 131 at both ends of the inner layer film 130 are respectively bonded to the middle layer film 122, thereby forming a three-layer film stent 100. For example, when the length of the film stent 100 is 100 mm and the diameter is 10 mm, the inner layer film 130 with an axial length of 70 mm is disposed in the inner cavity formed by the middle layer film 122, and the lengths of the bonding segments 131 at both ends of the inner layer film 130 are 5 mm. Wherein, the length of the bonding segment 131 refers to the length of the bonding segment 131 along the axial direction of the film stent 100, which is also the length of the bonding segment 131 along the axial direction of the skeleton 110 and the axial direction of the skeleton film 120. Of course, the above dimensions are only for illustration and do not limit the technical solution of the present invention.

[0057] Embodiment 4

[0058] This embodiment provides a film stent. The difference between the film stent in this embodiment and the film stent in Embodiment 1 is that the skeleton film in this embodiment only includes an outer layer film.

[0059] The film stent 100 includes a skeleton 110, an outer layer film 121, and an inner layer film 130. The outer layer film 121 is disposed on the entire outer peripheral surface of the skeleton 110, and the outer layer film 121 and the skeleton 110 are bonded to each other. The inner layer film 130 is disposed in the inner cavity surrounded by the skeleton 110. The inner layer film 130 is disposed on the entire skeleton 110. The bonding segments 131 at both ends of the inner layer film 130 are respectively bonded to the middle layer film 122. The separation segment 132 of the inner layer film 130 and the outer layer film 121 together enclose a hollow layer 140.

[0060] Since the outer layer film 121 disposed on the entire outer peripheral surface of the framework 110 is interconnected with the framework 110, when the shape of the framework 110 changes, the shape of the outer layer film 121 constrained by the framework 110 also changes with the change in the shape of the framework 110. The inner layer film 130 is disposed in the inner cavity surrounded by the framework 110. The bonding sections 131 at both ends of the inner layer film 130 are respectively bonded to the middle layer film 122, and a hollow layer 140 is formed by the separating section 132 of the inner layer film 130 and the outer layer film 121. Therefore, the separating section 132 of the inner layer film 130 is separated from the outer layer film 121 and the framework 110, and thus the separating section 132 of the inner layer film 130 is not constrained by the framework 110. When the shape of the framework 110 changes, since the inner layer film 130 is not completely constrained by the framework 110, the shape of the inner layer film 130 does not change with the change in the shape of the framework 110, that is, the inner layer film 130 is not easily wrinkled under the influence of the framework 110, but a relatively smooth transition is formed between the fixed end and the force application point, making the shape in the cavity closer to a circular tube shape, thereby reducing the risk of restenosis of the covered stent 100 caused by the wrinkles on the inner wall of the covered stent 100 after being implanted into the blood vessel.

[0061] This embodiment also provides a manufacturing method of the covered stent 100, which is as follows:

[0062] First, the outer layer film 121 is disposed on the entire outer peripheral surface of the framework 110 (which can be a corrugated framework made of NiTi wire), and at the same time, the outer layer film 121 and the framework 110 are bonded to each other to manufacture a complete single-layer stent.

[0063] Secondly, the inner layer film 130 is disposed in the inner cavity formed by the framework 110, so that the inner layer film 130 is disposed on the entire inner wall of the framework 110, and the bonding sections 131 at both ends of the inner layer film 130 are bonded to the outer layer film 121 and the framework 110, thereby forming a two-layer covered stent 100. For example, when the length of the covered stent 100 is 100 mm and the diameter is 10 mm, the regions 5 mm away from the proximal end and the distal end of the framework 110 can be bonded to the inner layer film 130, so that the inner layer film 130 and the outer layer film 121 are separated from each other in the region about 90 mm in the middle of the covered stent 100. Of course, in this embodiment, the covered stent 100 can also have other dimensions, which are not limited herein.

[0064] Embodiment Five

[0065] This embodiment provides a covered stent. Figure 7 It is a cross-sectional view of the covered stent in Embodiment Five of the present invention. Refer toFigure 7 The difference between the covered stent 100 in this embodiment and the covered stent 100 in the fourth embodiment is that in the covered stent 100 of this embodiment, the skeleton covering film 120 is only one layer, and the skeleton 110 is arranged in the film layer of the skeleton covering film 120.

[0066] Since the skeleton 110 is arranged in the film layer of the skeleton covering film 120, when the shape of the skeleton 110 changes, the shape of the skeleton covering film 120 constrained by the skeleton 110 will also change with the change of the shape of the skeleton 110. The inner covering film 130 is arranged in the inner cavity surrounded by the skeleton 110. The bonding sections 131 at both ends of the inner covering film 130 are respectively bonded to the skeleton covering film 120, and the separating section 132 of the inner covering film 130 and the skeleton covering film 120 enclose a hollow layer 140. Therefore, the separating section 132 of the inner covering film 130 is separated from the skeleton covering film 120, and thus the separating section 132 of the inner covering film 130 is not constrained by the skeleton 110. When the shape of the skeleton 110 changes, since the inner covering film 130 is not completely constrained by the skeleton 110, the shape of the inner covering film 130 will not change with the change of the shape of the skeleton 110, that is, the inner covering film 130 is not prone to form wrinkles under the influence of the skeleton 110, but will form a relatively smooth transition between the fixed end and the stress point, making the shape in the cavity closer to a circular tube shape, thereby reducing the risk of restenosis of the covered stent 100 caused by the wrinkles on the inner wall of the covered stent 100 after the covered stent 100 is implanted into the blood vessel.

[0067] In addition, since the skeleton 110 is arranged in the film layer of the skeleton covering film 120, a covering film can be completely arranged on the surface of the skeleton 110, thereby reducing the risk of the skeleton covering film 120 falling off from the skeleton 110.

[0068] This embodiment also provides a manufacturing method of the covered stent 100, which is as follows:

[0069] First, raw material filaments are sprayed on the skeleton 110 to form a layer of skeleton covering film 120, and at the same time, the skeleton 110 is arranged in the film layer of the skeleton covering film 120 to manufacture a complete single-layer stent. The raw material filaments can be PU, UHMWPE, ePTFE or PTFE.

[0070] Secondly, an inner-layer film 130 is disposed in the inner cavity formed by the framework 110, such that the inner-layer film 130 is disposed on the entire inner wall of the framework 110, and the bonding segments 131 at both ends of the inner-layer film 130 are respectively bonded to the framework film 120, thereby forming a two-layer film stent 100. For example, when the length of the film stent 100 is 100 mm and the diameter is 10 mm, the length of the bonding segments 131 at both ends of the inner-layer film 130 can be 5 mm, and the bonding segments 131 at both ends of the inner-layer film 130 can be bonded to the framework film 120, so that the inner-layer film 130 and the framework film 120 are separated from each other in an area of approximately 90 mm in the middle of the film stent 100. Of course, in this embodiment, the film stent 100 can also have other dimensions, which are not limited herein.

[0071] In the above embodiment, the framework is in a net tubular shape. In the schematic cross-sectional view of the framework along the axial direction, the framework is discontinuous. For specific reference, see Figure 1 、 Figure 5 、 Figure 6 and Figure 7 。

[0072] It should be noted that the various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0073] In addition, the "proximal end" and "distal end" in the above embodiments are the relative orientations, relative positions, and directions of elements or actions relative to each other from the perspective of a doctor using the medical device. Although the "proximal end" and "distal end" are not restrictive, the "proximal end" generally refers to the end of the medical device that is close to the doctor during normal operation, and the "distal end" generally refers to the end that first enters the patient's body. In addition, the term "or" in the above embodiments is generally used in the sense of including "and / or", unless otherwise explicitly stated. In the above embodiments, the "both ends" refer to the proximal end and the distal end.

[0074] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A covered stent, characterized in that, It includes a framework, a framework coating film, and an inner coating film. The framework coating film is disposed on the entire framework, and the framework coating film and the framework are adhesively bonded together. The inner coating film is disposed in the inner cavity of the coating film support. The inner coating film includes N bonding segments and M separating segments, where N≥2 and M = N - 1. The bonding segments and the separating segments are alternately arranged along the axial direction of the framework coating film and are connected into one body. The bonding segments are adhesively bonded to the framework coating film, and a hollow layer is formed between the separating segments and the framework coating film.

2. The covered stent according to claim 1, characterized in that, The inner coating film covers the entire inner cavity of the coating film support.

3. The covered stent according to claim 1, wherein The axial length of the inner coating film is less than the axial length of the coating film support, and both ends of the inner coating film do not coincide with both ends of the coating film support.

4. The covered stent according to any one of claims 1 to 3, characterized in that, The number of the bonding segments N = 2, and the number of the separating segments M = 1.

5. The covered stent according to any one of claims 1 to 3, characterized in that, The number of the bonding segments N≥3.

6. The covered stent according to any one of claims 1 to 3, characterized in that, The framework coating film includes an outer coating film and a middle coating film. The outer coating film is disposed on the entire outer peripheral surface of the framework, the middle coating film is disposed on the entire inner peripheral surface of the framework, and the outer coating film, the middle coating film, and the framework are adhesively bonded to each other in pairs.

7. The covered stent according to any one of claims 1 to 3, characterized in that, The framework is disposed in the film layer of the framework coating film.

8. The covered stent according to any one of claims 1 to 3, characterized in that, The framework coating film includes an outer coating film. The outer coating film is disposed on the entire outer peripheral surface of the framework, and the outer coating film and the framework are adhesively bonded together.

9. The covered stent according to any one of claims 1 to 3, characterized in that, The inner coating film is a PU film, a UHMWPE film, a PTFE film, or an ePTFE film.

10. A manufacturing method of a covered stent as described in any one of claims 1 to 9, characterized in that, The coating film support includes a framework, a framework coating film, and an inner coating film. The inner coating film includes N bonding segments and M separating segments, where N≥2 and M = N - 1. One bonding segment is provided at each of the two ends of the inner coating film. The bonding segments and the separating segments are alternately arranged along the axial direction of the framework coating film. The manufacturing method of the coating film support includes: Disposing the framework coating film on the framework and adhesively bonding the framework coating film and the framework together; and, Disposing the inner coating film in the inner cavity of the coating film support and adhesively bonding the bonding segments to the framework coating film.

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