Covered stent

Abstract

The present application relates to a kind of film-covered stents, including stent and the film covering on the stent, the stent includes multiple wave-shaped rings arranged in axial direction interval, the film-covered stent further include flexible wire, the wire connects the multiple wave-shaped rings, the wire includes first axial section, second axial section and first circumferential section, the two ends of the first axial section are connected with the two wave-shaped rings located in the nearest end and the farthest end respectively, one end of the first circumferential section is connected with the far end of the first axial section, and the other end is connected with the far end of the second axial section;Or, one end of the first circumferential section is connected with the near end of the first axial section, and the other end is connected with the near end of the second axial section.The film-covered stent is better flexible, and it is favorable to slow down and extend.

Description

Technical Field

[0001] This invention relates to the field of interventional medical devices, and in particular to a covered stent. Background Technology

[0002] This section provides only background information relevant to this disclosure and is not necessarily prior art.

[0003] In recent years, interventional therapy has become a growing trend in the treatment of cardiovascular diseases. With the continuous development of interventional techniques, the advantages of using endovascular stent grafts (ECLs) to treat aortic aneurysms and aortic dissections have become increasingly prominent. An ECL is an artificial blood vessel adapted to the size of the blood vessel. It mainly consists of an EC and a supporting stent. The EC is generally made of polymer materials such as polyester or e-PTFE, while the stent is primarily woven from nickel-titanium alloy wires. When a covered stent is delivered to the lesion site using a delivery device, the stent is first compressed into the sheath of the delivery device. Then, a puncture is performed on either the femoral or iliac artery. A guidewire is used to establish a path, and the delivery device is guided through the iliac artery—abdominal aorta—thoracic aorta (optional, depending on the lesion site)—aortic arch (optional, depending on the lesion site)—ascending aorta (optional, depending on the lesion site) to deliver the stent to the designated location of the lesion. The stent is then released, unfolding and adhering tightly to the vessel wall. The covering isolates blood flow from the lesion site, eliminating the impact of blood flow on the aneurysm wall and re-establishing normal blood circulation. Finally, the guidewire and delivery device are withdrawn, thus achieving interventional treatment for aneurysms and arterial dissections.

[0004] The use of endovascular stent grafts for interventional treatment is low-cost, has a short treatment cycle, and causes minimal trauma to the human body, thus gradually becoming the mainstream treatment for aortic aneurysm.

[0005] Currently, such as Figure 1 As shown, the support of the covered stent 1 typically includes a plurality of axially spaced corrugated annular elements 101, which are connected by axially extending connecting rods 102. The connecting rods 102 are typically rigid structures made of metallic materials, such as rigid rod-shaped structures made of nickel-titanium alloy.

[0006] The following problems arise when using a rigid connecting rod 102 in the coating support:

[0007] 1. The rigid connecting rod 102 reduces the flexibility of the film-coated support 1;

[0008] 2. Whether the rigid connecting rod 102 is set on one side or in two layers of the covered stent 1, the covered stent 1 will have directionality, the release direction must be fixed, it loses flexibility, increases the difficulty of release, and is prone to surgical failure.

[0009] 3、Since the rigid connecting rod 102 is provided, when the stent graft 1 is bent, the rigid connecting rod 102 always has a rebounding force, continuously stimulates the blood vessel wall, and can damage the blood vessel.

[0010] In order to solve the problems existing in the stent graft 1 with the rigid connecting rod 102, as shown in Figure 2 The existing stent graft 2 connects a plurality of wave-shaped rings 201 in the axial direction by using flexible wires 202, the flexible wires 202 extend in the axial direction, and the flexible wires 202 are connected to each wave-shaped ring 201 to form a plurality of fixed points 203, as shown in Figure 3 The flexible wires 202 are used to connect the plurality of wave-shaped rings 201 in the axial direction in the above connection mode, and have the following advantages:

[0011] 1. Compared with the rigid connecting rod 102, the use of the flexible wires 202 improves the flexibility of the stent graft 2;

[0012] 2. The directionality of the stent graft 1 using the rigid connecting rod 102 is eliminated, and the release direction of the stent graft 2 is more flexible;

[0013] 3. After the stent graft 2 is bent, the flexible wires 202 do not have a rebounding force, and the blood vessel is not damaged.

[0014] However, the use of the flexible wires 202 extending in the axial direction to connect the plurality of wave-shaped rings 201 also has disadvantages. The flexible wires 202 are used to connect adjacent wave-shaped rings 201, and the stent graft 2 is easily elongated during the sheathing and release of the stent graft 2. As shown in Figure 2 When subjected to a force F, the stent graft 2 is easily elongated in the direction of F.

[0015] The reasons for the elongation of the stent graft 2 are as follows:

[0016] 1. In the process of connecting the plurality of wave-shaped rings 201 by using the flexible wires 202, the plurality of wave-shaped rings 201 are first spaced apart and sleeved on a mold in the axial direction. There is no limiting structure on the mold to limit the wave-shaped rings 201, and the wave-shaped rings 201 are easily moved under stress. In the process of connecting the wires 202 to the wave-shaped rings 201, the wires 202 cannot be excessively tightened, and excessive tightening can cause the wave-shaped rings 201 to be stressed too much and the positions of the wave-shaped rings 201 to be unable to be accurately controlled. Therefore, the segment of the wires 202 between the adjacent wave-shaped rings 201 will have a certain slack, which can cause the wires 202 to be elongated when the stent graft 2 is subjected to a pulling force, so that the distance between the adjacent wave-shaped rings 201 is correspondingly increased, and the total axial length of the stent graft 2 is increased. When the number of wave-shaped rings 201 is large, the elongation effect of the stent graft 2 is more obvious.

[0017] 2、Flexible wire 202 is relatively smooth, and the joint between the flexible wire 202 and the wave-shaped ring 201 is likely to slide slightly, thus causing the overall axial length of the stent graft 2 to be extended as a whole;

[0018] 3、Flexible wire 202 is relatively smooth, and when the stent graft 2 is subjected to a pulling force, the pulling force acting on the end point is just parallel to the fixed point 203, thus causing the fixed point to be more likely to slip off, and the stent graft 2 to lose axial constraint, thus causing the overall axial length of the stent graft 2 to be extended as a whole. SUMMARY

[0019] Therefore, it is necessary to provide a stent graft which has good flexibility and is beneficial to slow down the extension.

[0020] A stent graft, comprising a stent and a covering film wrapped on the stent, the stent comprising a plurality of wave-shaped rings arranged at intervals along an axial direction, the stent graft further comprising a flexible wire, the wire connecting the plurality of wave-shaped rings, the wire comprising a first axial segment, a second axial segment and a first circumferential segment, two ends of the first axial segment being connected to two wave-shaped rings located at the nearest end and the farthest end respectively, one end of the first circumferential segment being connected to the farthest end of the first axial segment, and the other end being connected to the farthest end of the second axial segment.

[0021] Alternatively, one end of the first circumferential segment is connected to the nearest end of the first axial segment, and the other end is connected to the nearest end of the second axial segment.

[0022] In one embodiment, the wire further comprises a second circumferential segment, one end of the second circumferential segment being connected to the nearest end of the first axial segment, and the other end being connected to the nearest end of the second axial segment.

[0023] Alternatively, one end of the second circumferential segment is connected to the farthest end of the first axial segment, and the other end is connected to the farthest end of the second axial segment.

[0024] In one embodiment, the wire further comprises a third axial segment and a second circumferential segment, one end of the second circumferential segment being connected to the nearest end of the first axial segment, and the other end being connected to the nearest end of the third axial segment.

[0025] Alternatively, one end of the second circumferential segment is connected to the farthest end of the first axial segment, and the other end is connected to the farthest end of the third axial segment.

[0026] In one embodiment, the wire further comprises a third axial segment, a fourth axial segment, a second circumferential segment, and a third circumferential segment, one end of the second circumferential segment is connected to the proximal end of the first axial segment, and the other end is connected to the proximal end of the third axial segment, one end of the third circumferential segment is connected to the proximal end of the second axial segment, and the other end is connected to the proximal end of the fourth axial segment; or,

[0027] one end of the second circumferential segment is connected to the distal end of the first axial segment, and the other end is connected to the distal end of the third axial segment, one end of the third circumferential segment is connected to the distal end of the second axial segment, and the other end is connected to the distal end of the fourth axial segment.

[0028] In one embodiment, the wire further comprises a third axial segment, a fourth axial segment, a fifth axial segment, a second circumferential segment, a third circumferential segment, and a fourth circumferential segment, one end of the second circumferential segment is connected to the proximal end of the first axial segment, and the other end is connected to the proximal end of the third axial segment, one end of the third circumferential segment is connected to the proximal end of the second axial segment, and the other end is connected to the proximal end of the fourth axial segment, one end of the fourth circumferential segment is connected to the proximal end of the fourth axial segment, and the other end is connected to the proximal end of the fifth axial segment;

[0029] one end of the second circumferential segment is connected to the distal end of the first axial segment, and the other end is connected to the distal end of the third axial segment, one end of the third circumferential segment is connected to the distal end of the second axial segment, and the other end is connected to the distal end of the fourth axial segment, one end of the fourth circumferential segment is connected to the distal end of the fourth axial segment, and the other end is connected to the distal end of the fifth axial segment.

[0030] In one embodiment, the first axial segment and the second axial segment are parallel or substantially parallel; or the first axial segment, the second axial segment, and the first circumferential segment form a triangle.

[0031] In one embodiment, the first axial segment is connected to only two wave-shaped rings located at the proximal end and the distal end; or the first axial segment is sequentially connected to the plurality of wave-shaped rings.

[0032] In one embodiment, the second axial segment is sequentially connected to the plurality of wave-shaped rings; or the second axial segment is connected to part of the plurality of wave-shaped rings.

[0033] In one embodiment, there are two wires, and the two wires are symmetrically arranged on both sides of the covered stent with the axial center axis of the covered stent as the axis of symmetry;

[0034] Alternatively, the wires are four, and the four wires are arranged along the circumference of the covered stent and symmetrically arranged on both sides of the covered stent with the axial center axis of the covered stent as the axis of symmetry.

[0035] In one of the embodiments, the plurality of wave-shaped rings and the wires are embedded in the covering film.

[0036] In one of the embodiments, the covering film comprises an inner layer film, an intermediate layer film and an outer layer film which are sequentially stacked, the wave-shaped ring is embedded between the inner layer film and the intermediate layer film, and the wire is connected with the wave-shaped ring and extends between the intermediate layer film and the outer layer film.

[0037] In one of the embodiments, the wave-shaped ring is provided with a stopper, and the wire is stopped by the stopper.

[0038] In one of the embodiments, the wire has a diameter ranging from 0.01 to 0.2 mm.

[0039] In one of the embodiments, the stent comprises a first section, a second section and a transition section connected with the first section and the second section respectively, the outer diameter of the first section is smaller than that of the second section, the outer diameter of the transition section gradually increases from the end close to the first section to the end close to the second section, and the wire is connected with the stent by double knotting at the transition positions of the first section and the transition section and the transition section and the second section.

[0040] The plurality of wave-shaped rings of the covered stent are connected by flexible wires, and the covered stent has better flexibility compared with the covered stent connected by rigid connecting rods. The two ends of the first axial section are respectively connected with the two wave-shaped rings located at the nearest end and the farthest end, which limits the distance between the two wave-shaped rings at both ends as a whole. The two ends of the first circumferential section are respectively connected with the far end or the near end of the first axial section and the second axial section, which is conducive to dispersing the axial force acting on the far end or the near end of the first axial section and the second axial section, avoiding the wires from being elongated, and thus slowing down the elongation of the covered stent as a whole. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 FIG. 1 is a structural schematic diagram of a prior art covered stent;

[0042] Figure 2 FIG. 2 is a structural schematic diagram of another prior art covered stent;

[0043] Figure 3 FIG. 3 is a structural schematic diagram of a covered stent according to an embodiment of the present application; Figure 2The diagram shows the connection method between the filaments of the film-coated scaffold and the wave-shaped ring structure.

[0044] Figure 4 This is a schematic diagram of the structure of a film-coated stent according to an embodiment of the present invention;

[0045] Figure 5 for Figure 4 A schematic diagram showing the arrangement of the filaments in the film-coated stent.

[0046] Figure 6 for Figure 4 A magnified view of a portion of the image;

[0047] Figure 7 This is a schematic diagram of the arrangement of the threads according to another embodiment of the present invention;

[0048] Figure 8 This is a schematic diagram of the structure of a film-coated stent according to an embodiment of the present invention;

[0049] Figure 9 for Figure 8 A schematic diagram showing the arrangement of the filaments in the film-coated stent.

[0050] Figure 10 This is a schematic diagram of the connection between the filament and the wavy loop in one embodiment of the present invention, which is achieved by tying a single knot.

[0051] Figure 11 This is a schematic diagram of the connection between the filament and the wavy loop in one embodiment of the present invention, where they are connected by a double knot.

[0052] Figure 12 This is a schematic diagram of the structure of a film-coated stent according to another embodiment of the present invention;

[0053] Figure 13 for Figure 12 A schematic diagram showing the arrangement of the filaments in the film-coated stent.

[0054] Figure 14 for Figure 12 A magnified view of a portion of the image;

[0055] Figure 15 This is a schematic diagram of the structure of the abutment member according to another embodiment of the present invention;

[0056] Figure 16 This is a schematic diagram of the structure of the supporting member according to another embodiment of the present invention;

[0057] Figure 17 for Figure 16 A schematic diagram showing the arrangement of the filaments in the film-coated stent.

[0058] Figure 18 for Figure 16A schematic view of the arrangement of the wires of the covered stent shown in

[0059] Figure 19 A partial enlarged view of Figure 18

[0060] Figure 20 A partial enlarged view of Figure 18

[0061] Figure 21 A schematic view of the structure of the covered stent of another embodiment of the present application;

[0062] Figure 22 A schematic view of the arrangement of the wires of the covered stent shown in Figure 21

[0063] Figure 23 A schematic view of the structure of the covered stent of another embodiment of the present application;

[0064] Figure 24 A schematic view of the arrangement of the wires of the covered stent shown in Figure 23

[0065] Figure 25 A schematic view of the arrangement of the wires of another embodiment;

[0066] Figure 26 A schematic view of the connection relationship of the wave-shaped ring, the wires and the covering of the covered stent of an embodiment. DETAILED DESCRIPTION

[0067] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways beyond the specific embodiments described and it is therefore contemplated to cover all such modifications as fall within the scope of the application. It should be noted that the specific embodiments of the present application do not limit the scope of the present application.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0069] In the field of interventional medical devices, the term "distal" end is defined as the end of the device that is further from the operator during a procedure, and the term "proximal" end is defined as the end of the device that is closer to the operator during a procedure. The term "axial" refers to a direction parallel to an axis of the medical device, and the term "radial" refers to a direction perpendicular to the axial direction. The term "circumferential" refers to a direction around the axis of the luminal device.​​​​

[0070] Referring to Figure 4 In one embodiment, the covered stent 100 includes a stent 10 and a covering 20 covering the stent 10.

[0071] The stent 10 serves as a support for supporting the covering 20. The stent 10 is a hollow tube structure with open ends. The stent 10 includes a plurality of wave-shaped rings 110 arranged in an axial direction. Each wave-shaped ring 110 is a closed ring structure with wave crests and wave troughs formed by a plurality of wave bars 111 connected by a plurality of connecting pieces 112. Among them, the two connecting pieces 112 at both ends of each wave bar 111 are wave crests and wave troughs, respectively. The material of the wave-shaped ring 110 is a material with good biocompatibility and good elasticity. For example, nickel-titanium alloy, stainless steel, etc.

[0072] It should be noted that the specifications of the plurality of wave-shaped rings 110 can be completely the same or different. That is, the wave number (the number of wave crests or wave troughs), the angle of the adjacent two wave bars 111, the thickness of the wave bar 111, and other parameters of the plurality of wave-shaped rings 110 can be the same or different.

[0073] The wave-shaped ring 110 is made of a material with good biocompatibility and good elasticity, for example, nickel-titanium alloy, stainless steel, etc.

[0074] The plurality of wave-shaped rings 110 are connected by a flexible wire 30. In one embodiment, the wire 30 is a flexible wire made of a high molecular material, so that the covered stent 100 has good flexibility, which is beneficial to pass through the curved biological lumen structure. In one embodiment, the material of the wire 30 is polytetrafluoroethylene (PTFE) or polyethylene terephthalate (PET) or other biocompatible material. It should be noted that in other embodiments, the material of the wire 30 is not limited to PTFE and PET, and other high molecular materials that can connect the plurality of wave-shaped rings 110 and have good biocompatibility can also be used to make the wire. It should also be noted that the material of the wire 30 is not limited to high molecular material, and other materials that can make the wire 30 flexible and meet the biocompatibility requirements in clinical practice can also be used to make the wire 30.

[0075] Referring to Figure 5 In one embodiment, the wire 30 includes a first axial segment 31, a second axial segment 33, a third axial segment 35, a first circumferential segment 32, and a second circumferential segment 34.

[0076] The first axial segment 31, the second axial segment 33 and the third axial segment 35 extend in the axial direction respectively, and the first circumferential segment 32 and the second circumferential segment 34 extend in the circumferential direction respectively. The two ends of the first circumferential segment 32 are connected to the proximal end of the first axial segment 31 and the proximal end of the second axial segment 33 respectively. The two ends of the second circumferential segment 34 are connected to the distal end of the first axial segment 31 and the distal end of the third axial segment 35 respectively.

[0077] Further, the two ends of the first axial segment 31 are connected to the two wave-shaped rings 110 located at the proximal end and the distal end respectively. The connection points are denoted as a and b respectively. In this embodiment, the first axial segment 31 is connected to all the wave-shaped rings 110. The length of the second axial segment 33 is less than the length of the first axial segment 31. The second axial segment 33 is connected to all the wave-shaped rings 110 except the wave-shaped ring 110 located at the distal end. The two connection points at the two ends of the second axial segment 33 are denoted as c and d respectively. The length of the third axial segment 35 is less than the length of the first axial segment 31 and the second axial segment 33. In one embodiment, the third axial segment 35 is connected to only two adjacent wave-shaped rings 110. The two connection points at the two ends of the third axial segment 35 are denoted as e and f respectively. The first axial segment 31 and the second axial segment 33 together can reliably connect a plurality of wave-shaped rings 110, and the third axial segment 35 is connected to only two adjacent wave-shaped rings 110, so as to better fix the second circumferential segment 34 and enable the second circumferential segment 34 to disperse the force acting on the first axial segment 31, thereby saving materials and improving production efficiency.

[0078] Please refer to Figure 4 , Figure 5 and Figure 6 , the distal end of the second axial segment 33 is not connected to other segments of the wire 30, and the proximal end of the third axial segment 35 is not connected to other segments of the wire 30. The connection points of the wire 30 to the wave-shaped rings 110 are located on the wave rods 111. The distal end of the second axial segment 33 is connected to the wave rod 111, and the connection point is c. The proximal end of the third axial segment 35 is connected to the wave rod 111, and the connection point is f. As shown in Figure 6 , the connection point c and the connection point f are different positions of the same wave rod 111.

[0079] In one embodiment, the wire 30 is a one-piece structure. One wire 30 is wound around a circle to connect a plurality of wave-shaped rings 110 to form the first axial segment 31, the second axial segment 33, the third axial segment 35, the first circumferential segment 32 and the second circumferential segment 34. Further, the two free ends of the wire 30 are fixed on different positions of the same wave rod 111, thereby forming a coil structure with an opening.

[0080] It can be understood that in other embodiments, the wire 30 is a non-integral structure, the first axial segment 31, the second axial segment 33 and the third axial segment 35 respectively extend along the axial direction and are connected with the wave-shaped rings 110. The first circumferential segment 32 extends along the circumferential direction, and one end of the first circumferential segment 32 is connected with the proximal end of the first axial segment 31 and the wave rod 111, and the other end of the first circumferential segment 32 is connected with the proximal end of the second axial segment 33 and the wave rod 111. The second circumferential segment 34 extends along the circumferential direction, and one end of the second circumferential segment 34 is connected with the distal end of the first axial segment 31 and the wave rod 111, and the other end of the second circumferential segment 34 is connected with the distal end of the third axial segment 35 and the wave rod 111.

[0081] The two ends of the first axial segment 31 are connected with the two wave-shaped rings 110 located at the proximal end and the distal end respectively, and the distance between the two wave-shaped rings 110 at the two ends is limited as a whole. Moreover, the two ends of the first circumferential segment 32 are connected with the end points of the first axial segment 31 and the second axial segment 33 located at the proximal end respectively, and the direction of the force borne by the end points of the first axial segment 31 and the second axial segment 33 located at the proximal end is changed. Please refer back to Figure 5 When the wire 30 is subjected to an axial force, due to the stretching effect of the first circumferential segment 32, the direction of the force borne by the first axial segment 31 at the point b is changed, i.e. from the originally directly borne axial tensile force to the force Fb. Similarly, the force borne by the second axial segment 33 at the point d is changed from the axial tensile force to the force Fd. Therefore, compared with the connection mode of Figure 2 and Figure 3 , the axial tensile force borne by the first axial segment 31 and the second axial segment 33 is alleviated, thereby being beneficial to avoiding or alleviating the elongation of the first axial segment 31 and the second axial segment 33, and thus being beneficial to alleviating the elongation of the whole stent graft 100.

[0082] Further, the third axial segment 35 and the second circumferential segment 34 are arranged, and the direction of the force borne at the connection points a and e is changed, i.e. from the originally directly borne axial tensile force to the force Fa. Similarly, the force borne by the second axial segment 33 at the point e is changed from the axial tensile force to the force Fe. Therefore, the axial force borne by the two ends of the first axial segment 31 is alleviated, and it is further beneficial to avoiding or alleviating the elongation of the first axial segment 31.

[0083] It should be noted that in other embodiments, the third axial segment 35 and the second circumferential segment 34 can be omitted, and compared with Figure 3The connection mode of the single segment line shown in the figure, because of the double segment connection of the first axial segment 31 and the second axial segment 33, and the axial action on the proximal end of the first axial segment 31 and the second axial segment 33 can be slowed down, so the silk line 30 of the third axial segment 35 and the second circumferential segment 34 is also able to play a better slowing and lengthening role.

[0084] In Figure 5 The embodiment shown in the figure (the small dots on the figure represent the connection points, where a single dot represents a single knot, and a double dot represents a double knot, which will be described in detail below. Unless otherwise specified, the single dots and double dots of other figures represent the same meaning, which will not be described again below) each segment is connected to each wave-shaped annulus 110 within its length range (or extension range). Therefore, the silk line 30 has more connection points with the stent 10, the connection is more firm, which is beneficial to maintain the axial distance between adjacent wave-shaped annuli 110, thereby obtaining a better slowing and lengthening effect.

[0085] In an embodiment, the first axial segment 31 is only connected to part of the wave-shaped annuli 110. For example, the first axial segment 31 is connected to the two wave-shaped annuli 110 located at the proximal end and the distal end, and is connected to one wave-shaped annulus 110 in the middle.

[0086] In an embodiment, the first axial segment 31 is only connected to the two wave-shaped annuli 110 located at the proximal end and the distal end. Please refer to Figure 7 , the connection points of the first axial segment 31 with the wave-shaped annuli 110 are only a and b. The connection mode of the second axial segment 33, the third axial segment 35, the first circumferential segment 32 and the second circumferential segment 34 is the same as that shown in Figure 5 , which will not be described again here.

[0087] The first axial segment 31 is only connected to the two wave-shaped annuli 110 located at the proximal end and the distal end, and when connected, the slack of the first axial segment 31 can be better controlled, and the slack of the silk line 30 segment between adjacent wave-shaped annuli 110 can be reduced. Thus, under the premise of controlling the total length through the two connection points a and b at the ends, it is further beneficial to avoid or slow down the lengthening of the first axial segment 31, thereby slowing down the overall lengthening of the covered stent 100 in the axial direction.

[0088] It should be noted that whether the first axial segment 31 is only connected to the two wave-shaped annuli 110 located at the proximal end and the distal end, or the first axial segment 31 is connected to all the wave-shaped annuli 110, or the first axial segment 31 is only connected to part of the wave-shaped annuli 110, the number of connected wave-shaped annuli 110 is 3 or more, Figure 5 and Figure 7The proximal end and the distal end of the wire 30 can be replaced. That is, the two ends of the first circumferential segment 32 are connected to the distal end points of the first axial segment 31 and the second axial segment 33 respectively, and the two ends of the second circumferential segment 34 are connected to the proximal end point of the first axial segment 31 and the proximal end point of the third axial segment 35 respectively.

[0089] In an embodiment, the first axial segment 31, the second axial segment 33 and the third axial segment 35 are parallel or substantially parallel. The first circumferential segment 32 and the second circumferential segment 34 are parallel or substantially parallel. And, the first circumferential segment 32 is perpendicular or substantially perpendicular to the first axial segment 31 and the second axial segment 33. The second circumferential segment 34 is perpendicular or substantially perpendicular to the first axial segment 31 and the third axial segment 35. Wherein, substantially parallel means that the angle between the first axial segment 31 and the second axial segment 33 is greater than 0° but less than 10°. The angle between the first circumferential segment 32 and the second circumferential segment 34 is greater than 0° but less than 10°. Substantially perpendicular means that the angle between the two is 90°±10°. The substantially parallel and the substantially perpendicular throughout have the same meaning, and the rest is omitted.

[0090] Figure 5 And Figure 7 In the embodiment shown, the connection points of the wire 30 and the wave-shaped ring 110 are located on the wave rod 111. In other embodiments, the connection points of the wire 30 and the wave-shaped ring 110 are located on the connecting piece 112 and are at the wave crest or the wave trough, as shown in Figure 8 The connection points of the wire 30 and the wave-shaped ring 110 are located at the wave crest or the wave trough, which is beneficial to avoid the wire 30 from sliding on the wave-shaped ring 110, and makes the connection of the two more reliable.

[0091] And, please refer to Figure 8 and Figure 9 In other embodiments, the third axial segment 35 is omitted, and the wire 30 includes the first axial segment 31, the second axial segment 33, the first circumferential segment 32 and the second circumferential segment 34. The first axial segment 31 and the second axial segment 33 are parallel or substantially parallel, the two ends of the first circumferential segment 32 are connected to the proximal end of the first axial segment 31 and the proximal end of the second axial segment 33 respectively, and the two ends of the second circumferential segment 34 are connected to the distal end of the first axial segment 31 and the distal end of the second axial segment 33 respectively. The wire 30 is a closed coil structure. This wiring method can also change the force direction of the end points of the first axial segment 31 and the second axial segment 33, slow down the axial force received by the end points, thereby facilitating the slowing down of the axial elongation of the first axial segment 31 and the second axial segment 33, and thus slowing down the axial elongation of the whole stent graft 100.

[0092] In this embodiment, the first axial segment 31 can have only two ends connected to two wave-shaped rings 110, as shown inFigure 9 In another embodiment, the first axial segment 31 is connected with all the wave-shaped links 110. Alternatively, the first axial segment 31 is connected with only part of the wave-shaped links 110, and the number of the connected wave-shaped links 110 is 3 or more.

[0093] It is to be noted that in other embodiments, the second circumferential segment 34 can be omitted, the first axial segment 31 and the second axial segment 33 are parallel or substantially parallel, and the first axial segment 31 and the second axial segment 33 are equal in length, and the two ends of the first circumferential segment 32 are connected to the distal end or the proximal end of the first axial segment 31 and the second axial segment 33. In this way, the extension of the covered stent 100 can also be slowed down.

[0094] The wire 30 is connected to the wave-shaped links 110 by single knot and / or double knot. Figure 10 The single knot is shown. Taking the connection point located at the connecting piece 112 as an example, the single knot is the same as that of a general rope. For example, the wire 30 crosses the connecting piece 112, one end is passed through the other end, and the two ends are pulled tight. Figure 11 For the double knot, for example, the wire 30 crosses the connecting piece 112, one end is passed through the other end, and the two ends are pulled tight, then, repeat once, one end is passed through the other end, and then pulled tight. For another example, when one end of the wire 30 is connected to the wave-shaped link 110, there is only one free end, the wire 30 crosses the connecting piece 112, the free end of the wire 30 passes through the part of the wire 30 crossing the connecting piece 112, and is pulled tight to form a single knot, and then repeated once to form a double knot.

[0095] In an embodiment, the double knot is connected at the free end of the wire 30, and the single knot is connected at other positions. For example, Figure 5 and Figure 7 In the embodiment shown, both the connection point c and the connection point f are double knots, and the other positions are single knots. The double knot connection at the free end improves the reliability of the connection.

[0096] Please refer to Figure 12 In another embodiment, the wire 30 has a different wiring manner, i.e., the wire 30 has different connection manners with the plurality of wave-shaped links 110.

[0097] Please refer to Figure 13 The wire 30 includes the first axial segment 31, the second axial segment 33, the third axial segment 35, the fourth axial segment 37, the fifth axial segment 39, the first circumferential segment 32, the second circumferential segment 34, the third circumferential segment 36, and the fourth circumferential segment 38.

[0098] The first, second, third, fourth, and fifth axial segments 31, 33, 35, 37, and 39, respectively, extend in the axial direction. The first, second, third, and fourth circumferential segments 32, 34, 36, and 38, respectively, extend in the circumferential direction. The first circumferential segment 32 has its two ends connected to the distal end of the first axial segment 31 and the distal end of the second axial segment 33, respectively. The second circumferential segment 34 has its two ends connected to the proximal end of the first axial segment 31 and the proximal end of the third axial segment 35, respectively. The third circumferential segment 36 has its two ends connected to the proximal end of the second axial segment 33 and the proximal end of the fourth axial segment 37, respectively. The fourth circumferential segment 38 has its two ends connected to the distal end of the fourth axial segment 37 and the distal end of the fifth axial segment 39, respectively. The distal end of the third axial segment 35 is connected to the wave ring 110 only, without being connected to any other segment, and the proximal end of the fifth axial segment 39 is connected to the wave ring 110 only, without being connected to any other segment.

[0099] The first, second, third, fourth, and fifth axial segments 31, 33, 35, 37, and 39, respectively, are parallel or substantially parallel to each other. The first, second, third, and fourth circumferential segments 32, 34, 36, and 38, respectively, are parallel or substantially parallel to each other. Also, the first circumferential segment 32 is perpendicular or substantially perpendicular to the first and second axial segments 31 and 33, the second circumferential segment 34 is perpendicular or substantially perpendicular to the first and third axial segments 31 and 35, the third circumferential segment 36 is perpendicular or substantially perpendicular to the second and fourth axial segments 33 and 37, and the fourth circumferential segment 38 is perpendicular or substantially perpendicular to the fourth and fifth axial segments 37 and 39.

[0100] Figure 13In the shown connection mode, the connection process of one embodiment is as follows: one end of the wire 30 is firstly connected with the nearest wave-shaped ring 110 and the farthest wave-shaped ring 110, forming a first axial segment 31, and the connection points are a' and b' respectively. Then, the end of the wire 30 close to the connection point b' extends along the circumference to the adjacent wave rod 111 and is fixedly connected with the wave rod 111, forming a second circumferential segment 34. Then, the wire 30 extends axially from the proximal end to the distal end and is connected with the wave-shaped ring 110, forming a third axial segment 35. Continuing the wire, the other end of the wire 30 close to the connection point a' extends along the circumference to the adjacent wave rod 111 and is fixedly connected with the wave rod 111, forming a first circumferential segment 32. The wire 30 continues to extend axially from the distal end to the proximal end and is connected with the wave-shaped ring 110 in sequence, forming a second axial segment 33. Then, the wire 30 extends along the circumference from the nearest wave-shaped ring 110 to the adjacent wave rod 111 and is fixedly connected with the wave rod 111, forming a third circumferential segment 36. Further, the wire 30 continues to extend axially from the proximal end to the distal end and is connected with only the farthest wave-shaped ring 110, forming a fourth axial segment 37. The wire 30 continues to extend along the circumference to the adjacent wave rod 111 and is fixedly connected with the wave rod 111, forming a fourth circumferential segment 38. Finally, the wire 30 extends axially from the distal end to the proximal end, and the free end of the wire 30 is connected with the wave rod 111, forming a fifth axial segment 39, and the connection of the wire 30 with the wave-shaped ring 110 is completed.

[0101] It should be noted that the connection process and sequence described above are only exemplary, and different wire routing modes and sequences can be used to achieve the same connection mode.

[0102] Please continue to refer to Figure 12 and Figure 13 In one embodiment, the first axial segment 31 is connected with only the farthest wave-shaped ring 110 and the nearest wave-shaped ring 110, and the connection points are a' and b' respectively, and the connection points a' and b' are connected by double knots. The second axial segment 33 is connected with each wave-shaped ring 110. The distal end of the third axial segment 35 is connected with the wave-shaped ring 110 by a double knot, and the connection point is c'. The fourth axial segment 37 is connected with only the farthest wave-shaped ring 110 and the nearest wave-shaped ring 110, and the connection points are d' and e' respectively, and the connection points d' and e' are connected by double knots. The distal end of the fifth axial segment 39 is connected with the wave-shaped ring 110 by a single knot, and the connection point is f', and the proximal end is connected with the wave-shaped ring 110 by a double knot, and the connection point is g'. By connecting the double knots at a', b', c', d', e' and g', the connection of the wire 30 with the wave-shaped ring 110 is more reliable.

[0103] It should be noted that in other embodiments, the third axial segment 35, the fourth axial segment 37 and the fifth axial segment 39 can be omitted at the same time, or the fifth axial segment 39 can be omitted. The second circumferential segment 34, the third circumferential segment 36 and the fourth circumferential segment 38 can be omitted at the same time, or the fourth axial segment 37 can be omitted.

[0104] Please refer to Figure 12 and Figure 14 In an embodiment, the wave-shaped ring 110 further comprises a holding member 113 for holding the polymer filament 30. As shown in Figure 14 , the filament 30 is held by the holding member 113 to avoid the filament 30 from sliding and changing the relative position between the filament 30 and the wave-shaped ring 110 to form a slack zone, thereby facilitating to avoid or slow down the elongation of the filament 30.

[0105] In an embodiment, the holding member 113 is sleeved on the wave rod 111, and the filament 30 is held by the holding member 113 when the filament 30 is connected to the wave rod 111.

[0106] Please refer to Figure 15 In an embodiment, the holding member 113 is a rod member or a sheet structure extending from the small-bend side of the connecting member 112 to the large-bend side of the connecting member 112. The holding member 113 forms a gap with the wave rod 111 on both sides, and when the filament 30 is connected to the connecting member 112, the node of the filament 30 can be located in the gap, and / or the filament 30 can be wound on the holding member 113.

[0107] Please refer to Figure 16 In an embodiment, the holding member 113 is a barb provided on the wave rod 111. The filament 30 can be hooked with the holding member 113.

[0108] Please refer to Figure 17 Another embodiment of the covered stent 100, the filament 30 has a different wiring manner, i.e. the connection manner of the filament 30 to the plurality of wave-shaped rings 110 is different. The covered stent 100 has an axial center line A-A.

[0109] Please refer to Figure 18 The filament 30 comprises a first axial segment 31, a second axial segment 33, a third axial segment 35, a fourth axial segment 37, a first circumferential segment 32, a second circumferential segment 34 and a third circumferential segment 36.

[0110] The first axial segment 31, the second axial segment 33, the third axial segment 35 and the fourth axial segment 37 respectively extend in the axial direction. The first circumferential segment 32, the second circumferential segment 34 and the third circumferential segment 36 respectively extend in the circumferential direction. The two ends of the first circumferential segment 32 are connected to the proximal end of the first axial segment 31 and the proximal end of the second axial segment 33 respectively. The two ends of the second circumferential segment 34 are connected to the distal end of the first axial segment 31 and the distal end of the third axial segment 35 respectively. The two ends of the third circumferential segment 36 are connected to the distal end of the second axial segment 33 and the distal end of the fourth axial segment 37 respectively. The proximal end of the third axial segment 35 is connected to the wave-shaped ring 110 only, without being connected to other segments. The proximal end of the fourth axial segment 37 is connected to the wave-shaped ring 110 only, without being connected to other segments.

[0111] The first axial segment 31, the second axial segment 33, the third axial segment 35 and the fourth axial segment 37 are parallel or substantially parallel to each other. The first circumferential segment 32, the second circumferential segment 34 and the third circumferential segment 36 are parallel or substantially parallel to each other, or the second circumferential segment 34 and the third circumferential segment 36 are on the same straight line. Furthermore, the first circumferential segment 32 is perpendicular or substantially perpendicular to the first axial segment 31 and the second axial segment 33, the second circumferential segment 34 is perpendicular or substantially perpendicular to the first axial segment 31 and the third axial segment 35, and the third circumferential segment 36 is perpendicular or substantially perpendicular to the second axial segment 33 and the fourth axial segment 37.

[0112] A straight line B-B extending in the axial direction is perpendicular to the first circumferential segment 32, and the straight line B-B passes through the midpoint of the first circumferential segment 32, and the straight line B-B is parallel to the axial center line A-A of the covered stent 100. The first axial segment 31 and the second axial segment 33 are symmetrically arranged with the straight line B-B as the axis of symmetry. The third axial segment 35 and the fourth axial segment 37 are symmetrically arranged with the straight line B-B as the axis of symmetry. The second circumferential segment 34 and the third circumferential segment 36 are symmetrically arranged with the straight line B-B as the axis of symmetry.

[0113] In the present embodiment, the total length is controlled by using the first axial segment 31 and the second axial segment 33. Furthermore, please refer to Figure 19 and Figure 20, the end connection points a" and b" of the first axial segment 31 are respectively constrained by the second circumferential segment 34 and the first circumferential segment 32, so that the directions of the forces F1 and F2 acting on the end connection points a" and b" are not directly axial directions, but are offset by an angle from the axial direction, thereby slowing down the axial forces acting on the end connection points a" and b". The end connection points c" and d" of the second axial segment 33 are respectively constrained by the third circumferential segment 36 and the first circumferential segment 32, so that the directions of the forces F3 and F4 acting on the end connection points c" and d" are not directly axial directions, but are offset by an angle from the axial direction, thereby slowing down the axial forces acting on the end connection points c" and d". Thus, it is beneficial to avoid or slow down the elongation of the first axial segment 31 and the second axial segment 33.

[0114] Please go back to Figure 18 In an embodiment, the end connection points a", b", c" and d" are connected to the wave-shaped ring 110 by double knots, which is further beneficial to avoid or slow down the elongation of the first axial segment 31 and the second axial segment 33.

[0115] In an embodiment, the proximal end of the third axial segment 35 is connected to the wave-shaped ring 110 by a double knot, and the proximal end of the fourth axial segment 37 is connected to the wave-shaped ring 110 by a double knot. Since the proximal end of the third axial segment 35 is not connected to other segments, and the proximal end of the fourth axial segment 37 is not connected to other segments, the fixation by double knots is beneficial to better fix the third axial segment 35 and the fourth axial segment 37, so as to ensure that the two ends of the second circumferential segment 34 are reliably fixed, thereby changing the force direction of the end connection point a" of the first axial segment 31. Similarly, it ensures that the two ends of the fourth axial segment 37 are reliably fixed, thereby changing the force direction of the end connection point c" of the second axial segment 33. Thus, the axial forces acting on the first axial segment 31 and the second axial segment 33 are smaller, which is beneficial to avoid or slow down the axial elongation.

[0116] In an embodiment, the first axial segment 31 and the second axial segment 33 have equal length. The first axial segment 31 is connected to only two wave-shaped rings 110 at two ends, i.e. connection points a” and b”. The two wave-shaped rings 110 connected to the first axial segment 31 are the wave-shaped rings 110 at the farthest end and the nearest end. The second axial segment 33 is connected to all the wave-shaped rings 110, forming a plurality of connection points, the number of which is equal to the number of the wave-shaped rings 110. The third axial segment 35 and the fourth axial segment 37 have equal length. Moreover, the third axial segment 35 is connected to only two adjacent wave-shaped rings 110, and the fourth axial segment 37 is connected to only two adjacent wave-shaped rings 110, so that the force direction of the connection points a” and c” can be changed, and the length of the wire 30 can be reduced under the premise of reliable connection and the ability to avoid or slow down elongation, which is conducive to reducing the cost of raw materials, while saving the step of knotting and improving the preparation efficiency.

[0117] Please refer to Figure 21 In an embodiment, the covered stent 100 is a tubular structure with unequal diameters. The stent 10 comprises a first segment 11, a second segment 12, and a transition segment 13 connected to the first segment 11 and the second segment 12, respectively. The outer diameter of the first segment 11 is smaller than the outer diameter of the second segment 12. From the end close to the first segment 11 to the end close to the second segment 12, the outer diameter of the transition segment 13 gradually increases, and the outer diameter of the transition segment 13 gradually increases from a value equal to the outer diameter of the first segment 11 to a value equal to the outer diameter of the second segment 12. In an embodiment, the transition segment 13 comprises a proximal transition segment 131 and a distal transition segment 132, and the first segment 11, the distal transition segment 132, the proximal transition segment 131, and the second segment 12 are arranged in sequence from the distal end to the proximal end in the axial direction. The first segment 11 comprises at least one first wave-shaped ring 110’, the distal transition segment 132 comprises at least one second wave-shaped ring 110”, the proximal transition segment 131 comprises at least one third wave-shaped ring 110”’, and the second segment 12 comprises at least one fourth wave-shaped ring 110””. The outer diameter of the first wave-shaped ring 110’ is smaller than the outer diameter of the second wave-shaped ring 110”, the outer diameter of the second wave-shaped ring 110” is smaller than the outer diameter of the third wave-shaped ring 110”’, and the outer diameter of the third wave-shaped ring 110”’ is smaller than the outer diameter of the fourth wave-shaped ring 110”, so that the stent 10 is a stent with unequal diameters, and the covered film 20 is wrapped on the stent 10 to form a tubular structure with unequal diameters.

[0118] It can be understood that when the number of the first wave-shaped annular members 110' is multiple, the multiple first wave-shaped annular members 110' are arranged in axial intervals. When the number of the second wave-shaped annular members 110" is multiple, the multiple second wave-shaped annular members 110" are arranged in axial intervals. When the number of the third wave-shaped annular members 110"'is multiple, the multiple third wave-shaped annular members 110"'are arranged in axial intervals. When the number of the fourth wave-shaped annular members 110" " is multiple, the multiple fourth wave-shaped annular members 110" " are arranged in axial intervals.

[0119] Please refer to Figure 22 , the wire 30 comprises a first axial segment 31, a second axial segment 33, a first circumferential segment 32 and a second circumferential segment 34.

[0120] The first axial segment 31 is a straight line extending in the axial direction. The second axial segment 33 comprises a first segment 331, a second segment 332, a third segment 333 and a fourth segment 334 extending in the axial direction in sequence. The first segment 331 is parallel or substantially parallel to the first axial segment 31, the second segment 332 is inclined relative to the first segment 331, the third segment 333 is inclined relative to the second segment 332, and the fourth segment 334 extends in the axial direction. The two ends of the first circumferential segment 32 are connected to the proximal end of the first axial segment 31 and the proximal end of the fourth segment 334, respectively. The two ends of the second circumferential segment 34 are connected to the distal end of the first axial segment 31 and the distal end of the first segment 331, respectively.

[0121] Wherein, the first segment 331 of the second axial segment 33 extends from one end of the first segment 11 of the stent 10 to the other end. The first segment 331 is parallel to the generatrix of the first segment 11. The second segment 332 extends from one end of the distal transition segment 132 to the other end. The second segment 332 is parallel to the generatrix of the distal transition segment 132. The third segment 333 extends from one end of the proximal transition segment 131 to the other end. The third segment 333 is parallel to the generatrix of the proximal transition segment 131. The fourth segment 334 extends from one end of the second segment 12 to the other end. The fourth segment 334 is parallel to the generatrix of the second segment 12.

[0122] At the distal end of the first axial segment 331, the wire 30 and the first wave-shaped ring 110' are connected by a double knot. At the transition between the first axial segment 331 and the second axial segment 332, the wire 30 and the first wave-shaped ring 110' are connected by a double knot. At the transition between the second axial segment 332 and the third axial segment 333, the wire 30 and the second wave-shaped ring 110" are connected by a double knot. At the transition between the third axial segment 333 and the fourth axial segment 334, the wire 30 and the third wave-shaped ring 110'" are connected by a double knot. At the proximal end of the fourth axial segment 334, the wire 30 and the fourth wave-shaped ring 110"" are connected by a double knot. In this way, the connection between the wire 30 and the stent 10 is more reliable, which is conducive to restraining the wave-shaped rings (the first wave-shaped ring 110', the second wave-shaped ring 110", the third wave-shaped ring 110'" and the fourth wave-shaped ring 110"") of different diameters of the stent 10, thus being conducive to restraining the distance between adjacent wave-shaped rings and slowing down the extension of the covered stent 100.

[0123] In an embodiment, as shown in FIG. 1, the first axial segment 31 is connected to all the wave-shaped rings in the axial direction and is connected by a single knot. In other embodiments, all the wave-shaped rings can be connected by a double knot. Figure 22

[0124] In another embodiment, the first axial segment 31 is connected to only two wave-shaped rings located at the proximal end and the distal end, i.e., the first axial segment 31 is connected to only the first wave-shaped ring 110' located at the distal end and the fourth wave-shaped ring 110"" located at the proximal end, and is connected by a double knot.

[0125] It should be noted that in other embodiments, one of the proximal transition segment 131 and the distal transition segment 132 of the transition segment 13 can be omitted. Alternatively, in other embodiments, the transition segment 13 further comprises at least one intermediate transition segment. The wave-shaped ring of the intermediate transition segment has an outer diameter greater than that of the proximal transition segment and less than that of the distal transition segment.

[0126] Regardless of whether the transition segment 13 comprises wave-shaped rings of different diameters, all the transition positions of the wave-shaped rings of different diameters in the entire stent 10 are fixedly connected to the wire 30 by a double knot to improve the reliability of the connection.

[0127] Please refer to FIG. 1, in an embodiment, the arrangement of the wire 30 is different. Please refer to FIG. 2 together, Figure 23 in an embodiment, the wire 30 comprises the first axial segment 31, the second axial segment 33 and the first circumferential segment 32. Figure 24

[0128] ​​The first axial segment 31 and the second axial segment 33 respectively extend in the axial direction, and neither of the first axial segment 31 and the second axial segment 33 is parallel to the axial center axis A-A of the covered stent 100. That is, the axial extension means that the distal end and the proximal end of the first axial segment 31 are respectively located at different positions in the axial direction, and the distal end and the proximal end of the second axial segment 33 are respectively located at different positions in the axial direction, and it is not necessarily required that the first axial segment 31 and the second axial segment 33 are parallel to the axial center axis A-A.

[0129] In an embodiment, the distal end of the first axial segment 31 and the distal end of the second axial segment 33 intersect, and the two ends of the first circumferential segment 32 are respectively connected to the proximal end of the first axial segment 31 and the proximal end of the second axial segment 33, so that the wire 30 has a closed triangular shape. In this way, the plurality of wave-shaped rings 110 can also be reliably connected, and the stress direction of the connected wave-shaped rings 110 is not directly the axial direction, which is beneficial to slow down the axial elongation of the covered stent 100.

[0130] In an embodiment, the first axial segment 31 is connected only to the two wave-shaped rings 110 located at the proximal end and the distal end, and the second axial segment 33 is connected to all the wave-shaped rings 110. Moreover, double knots are used to fix the end points of the first axial segment 31, the second axial segment 33 and the first circumferential segment 32, and single knots are used to connect the remaining positions. In this embodiment, the total length is controlled by the first axial segment 31, the middle part of the first axial segment 31 has no connection point, the slack of the first axial segment 31 can be better controlled, and the slack of the wire 30 segment between adjacent wave-shaped rings 110 is reduced. Therefore, under the premise of controlling the total length by the two end points of the first axial segment 31 at the end, it is further beneficial to avoid or slow down the elongation of the first axial segment 31, thereby slowing down the axial elongation of the covered stent 100 as a whole.

[0131] It can be understood that, in another embodiment, the first axial segment 31 is connected to all the wave-shaped rings 110, and the second axial segment 33 is connected to all the wave-shaped rings 110. In another embodiment, the first axial segment 31 is connected to all the wave-shaped rings 110, and the second axial segment 33 is connected only to the two wave-shaped rings 110 located at the proximal end and the distal end.

[0132] It can be understood that, in other embodiments, the first axial segment 31 and the second axial segment 33 can intersect at the proximal end, and the first circumferential segment 32 is connected to the distal end of the first axial segment 31 and the distal end of the second axial segment 33 respectively.

[0133] In an embodiment, the first circumferential segment 32 is connected to multiple waves of the same wave-shaped ring 110, for example, the first circumferential segment 32 is connected to all the waves within the extension range of the first circumferential segment 32, so that the first circumferential segment 32 can bear a larger force to reliably connect the proximal ends of the first axial segment 31 and the second axial segment 33, while changing the force direction of the first axial segment 31 and the second axial segment 33 at the proximal end, thereby avoiding or slowing down the extension of the covered stent 100.

[0134] Please refer to Figure 25 In an embodiment, the wire 30 further comprises a second circumferential segment 34, the second circumferential segment 34 is parallel or substantially parallel to the first circumferential segment 32, one end of the first axial segment 31 is connected to one end of the first circumferential segment 32 and one end of the second circumferential segment 34, and the other end of the first axial segment 31 is connected to the other end of the first circumferential segment 32 and the other end of the second circumferential segment 33. Moreover, the line connecting the midpoint of the first circumferential segment 32 and the midpoint of the second circumferential segment 34 is a straight line C-C, and the first axial segment 31 and the second axial segment 33 are symmetrically arranged with the straight line C-C as the axis of symmetry, thereby forming a closed quadrilateral. The quadrilateral can be a square, a rectangle, or an isosceles trapezoid.

[0135] Regardless of the arrangement of the wire 30, whether it only includes the first axial segment 31, the second axial segment 33, and the first circumferential segment 32, or it includes the first axial segment 31, the second axial segment 33, the first circumferential segment 32, and the second circumferential segment 34, or it includes the first axial segment 31, the second axial segment 33, the third axial segment 35, the fourth axial segment 37, the first circumferential segment 32, the second circumferential segment 34, and the third circumferential segment 36, or it includes the first axial segment 31, the second axial segment 33, the third axial segment 35, the fourth axial segment 37, the fifth axial segment 39, the first circumferential segment 32, the second circumferential segment 34, the third circumferential segment 36, and the fourth circumferential segment 38, in an embodiment, the covered stent 100 comprises two wires 30, the two wires 30 are arranged at 180° and symmetrically arranged on both sides of the covered stent 100 with the axial center axis A-A of the covered stent 100 as the axis of symmetry. Such arrangement is further conducive to slowing down the extension of the covered stent 100, and makes the force on both sides of the covered stent 100 uniform, avoiding the phenomenon of torsion of the covered stent 100.

[0136] In an embodiment, the covered stent 100 comprises four wires 30, which are spaced apart along the circumference of the covered stent 100 and arranged in pairs at 180°, and symmetrically arranged on both sides of the covered stent 100 with the axial center axis A-A of the covered stent 100 as the axis of symmetry. The arrangement of four wires 30 is conducive to better constraining the distance between adjacent wave-shaped rings 110, achieving better effect of slowing down the elongation of the covered stent 100, and at the same time, better avoiding the phenomenon of twisting of the covered stent 100.

[0137] In an embodiment, the wire diameter of the wire 60 is 0.01-0.2 mm. Greater than or equal to 0.01 mm ensures that the wire 30 has sufficient strength to avoid breaking of the wire 30. Less than or equal to 0.2 mm, on the one hand, avoids the wire diameter of the wire 30 being too large to form a local protrusion after the wire 30 is embedded in the covering 20, which has an adverse effect on blood flow; on the other hand, the strength of the wire 30 meets the requirements and does not need to be too large to save materials.

[0138] The material of the covering 20 is polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), or polytetrafluoroethylene-propylene copolymer (FEP), etc. which has good biocompatibility.

[0139] Please refer to Figure 26 , the covering 20 comprises an inner layer film 21, an intermediate layer film 22 and an outer layer film 23 which are stacked in sequence. The wave-shaped ring 110 is embedded between the inner layer film 21 and the intermediate layer film 22, the wire 30 is hooked with the wave-shaped ring 110 and the main body of the wire 30 extends between the intermediate layer film 22 and the outer layer film 23.

[0140] The inner layer film 21, the intermediate layer film 22 and the outer layer film 23 are combined together by heat treatment, so that the covering 20, the stent 10 and the wire 30 are integrated. This way makes the wire 30 located inside the covering 20, which is conducive to better protecting the wire 30 and avoiding the wire 30 from being broken due to scratching, thereby ensuring that the adjacent wave-shaped rings 110 are reliably constrained by the wire 30 to slow down the overall elongation of the covered stent 100. Moreover, the main body of the wire 30 (except the connection point) extends between the intermediate layer film 22 and the outer layer film 23, while the wave-shaped ring 110 is located between the inner layer film 21 and the intermediate layer film 22, so that the main body of the wire 30 and the wave-shaped ring 110 are separated by the intermediate film layer 22, which is conducive to avoiding the undesired interference between the wave-shaped ring 110 and the wire 30 to cause the wire 30 to break, thereby facilitating to ensure the reliability of the connection.

[0141] When the wave-shaped ring 110 further comprises the abutting member 113, the abutting member 113 is located between the inner layer film 21 and the intermediate layer film 22. Whether the thread 30 is connected to the wave-shaped ring 110 by a single knot or a double knot, the thread 30 is wound on the wave-shaped ring 110, the knot of the thread 30 is located between the inner layer film 21 and the intermediate layer film 22, and the thread 30 extends between the intermediate layer film 22 and the outer layer film 23.

[0142] In an embodiment, when connected, the thread 30 is connected to a piercing member (not shown) to pass through the intermediate layer film 22 after knotting. For example, the piercing member is a sewing needle. After the thread 30 is wound on one wave-shaped ring 110 (the wave bar 111 or the connecting member 112) and knotted, the piercing member passes through the intermediate layer film 22, and after the thread 30 extends between the intermediate layer film 22 and the outer layer film 23 for a certain distance, the piercing member passes through the intermediate layer film 22 again and is connected to another wave-shaped ring 110, and the step is repeated so that the knot of the thread 30 is located between the inner layer film 21 and the intermediate layer film 22, and the main body of the thread 30 extends between the intermediate layer film 22 and the outer layer film 23.

[0143] It should be noted that the inner layer film 21 can be a single-layer polymer film or a multi-layer polymer film, the intermediate layer film 22 can be a single-layer polymer film or a multi-layer polymer film, and the outer layer film 23 can also be a single-layer polymer film or a multi-layer polymer film. A plurality of single-layer polymer films can be stacked and then fused into one by heat treatment to form the inner layer film 21, the intermediate layer film 22, and / or the outer layer film 23.

[0144] It should also be noted that the materials of the inner layer film 21, the intermediate layer film 22, and the outer layer film 23 can be the same or different. When the materials of the inner layer film 21, the intermediate layer film 22, and the outer layer film 23 are different, the materials of the inner layer film 21, the intermediate layer film 22, and the outer layer film 23 should each meet the requirement of biocompatibility and should ensure that the three can be fused into one after heat treatment.

[0145] In an embodiment, the thickness of the inner layer film 21 is greater than the thickness of the intermediate layer film 22 and the outer layer film 23, and the thickness of the intermediate layer film 22 is less than the thickness of the outer layer film 23. When the inner layer film 21, the intermediate layer film 22, and the outer layer film 23 are fused into one, the two sides of the wave-shaped ring 110 are respectively the complex of the intermediate layer film 22 and the outer layer film 23 and the inner layer film 21, and the thickness of the inner layer film 21 is greater, so that the wave-shaped ring 110 can be better covered by the polymer films on both sides, on the one hand, the wave-shaped ring 110 can be reliably connected with the covering film 20, and on the other hand, the inner layer film 21 is not too thin to easily cause the wave-shaped ring 110 to be exposed from the covering film 20. Moreover, during the connection process, the piercing member drives the thread 30 to pass through the intermediate layer film 22 multiple times, and the thickness of the intermediate layer film 22 is smaller to facilitate the piercing member and the thread 30 to pass through.

[0146] The above covered stent 100, by reasonably setting the first axial section 31, the second axial section 33 and the first circumferential section 32 of the wire 30, reliably connects the plurality of wave-shaped rings 110, which is conducive to avoiding or slowing the distance between the wave-shaped rings 110 from becoming larger and causing the covered stent 100 to be axially elongated. Thus, it is conducive to slowing the elongation of the covered stent 100. Moreover, since the wire 30 is a flexible wire, the adjacent wave-shaped rings 110 are flexibly connected, so that the covered stent 100 has good flexibility, which is conducive to the delivery of the covered stent 100. At the same time, the covered stent 100 has no directionality, so that it is easier to release, which is conducive to improving the success of the operation. Moreover, the continuous stimulation of the tissue wall by the rigid connecting rod in the prior art can be avoided, the long-term clinical risk can be avoided or reduced, and the safety of use can be improved.

[0147] The arrangement of the wire 30 of different embodiments and the effect of slowing the elongation of the covered stent 100 are shown in Table 1 below. The test method of the data in the table is as follows: the length L1 of the covered stent 100 in a natural state is measured, then the covered stent 100 is compressed and loaded into a sheath, and then the covered stent 100 is released from the sheath, and then the length L2 of the covered stent 100 in a natural state is tested, and the elongation value of the covered stent 100 = L2-L1 (mm). Each group tests the elongation value of 5 covered stents of the same specification and the same wire arrangement.

[0148] As can be seen intuitively from Table 1, compared with the connection mode of the prior art, the covered stent 100 can effectively slow the elongation.

[0149] Table 1

[0150]

[0151]

[0152] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present disclosure.

[0153] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A covered stent comprising a stent and a covering covering the stent, the stent comprising a plurality of wave-like rings arranged at intervals in an axial direction, characterized in that, The covered stent further comprises a flexible wire connecting the plurality of wave-shaped rings, the wire comprising a first axial segment, a second axial segment and a first circumferential segment, two ends of the first axial segment being connected to two wave-shaped rings located at the proximal end and the distal end respectively; wherein one end of the first circumferential segment is connected to the distal end of the first axial segment, and the other end is connected to the distal end of the second axial segment, or one end of the first circumferential segment is connected to the proximal end of the first axial segment, and the other end is connected to the proximal end of the second axial segment.

2. The stent of claim 1, wherein The wire further comprises a second circumferential segment, one end of the second circumferential segment being connected to the proximal end of the first axial segment, and the other end being connected to the proximal end of the second axial segment; or one end of the second circumferential segment is connected to the distal end of the first axial segment, and the other end is connected to the distal end of the second axial segment.

3. The stent of claim 1, wherein The wire further comprises a third axial segment and a second circumferential segment, one end of the second circumferential segment being connected to the proximal end of the first axial segment, and the other end being connected to the proximal end of the third axial segment; or one end of the second circumferential segment is connected to the distal end of the first axial segment, and the other end is connected to the distal end of the third axial segment.

4. The stent of claim 1, wherein The wire further comprises a third axial segment, a fourth axial segment, a second circumferential segment and a third circumferential segment, one end of the second circumferential segment being connected to the proximal end of the first axial segment, and the other end being connected to the proximal end of the third axial segment, one end of the third circumferential segment being connected to the proximal end of the second axial segment, and the other end being connected to the proximal end of the fourth axial segment; or one end of the second circumferential segment is connected to the distal end of the first axial segment, and the other end is connected to the distal end of the third axial segment; one end of the third circumferential segment is connected to the distal end of the second axial segment, and the other end is connected to the distal end of the fourth axial segment.

5. The stent of claim 1, wherein The wire further comprises a third axial segment, a fourth axial segment, a fifth axial segment, a second circumferential segment, a third circumferential segment and a fourth circumferential segment, one end of the second circumferential segment being connected to the proximal end of the first axial segment, and the other end being connected to the proximal end of the third axial segment, one end of the third circumferential segment being connected to the proximal end of the second axial segment, and the other end being connected to the proximal end of the fourth axial segment, one end of the fourth circumferential segment being connected to the proximal end of the fourth axial segment, and the other end being connected to the proximal end of the fifth axial segment; or one end of the second circumferential segment is connected to the distal end of the first axial segment, and the other end is connected to the distal end of the third axial segment, one end of the third circumferential segment is connected to the distal end of the second axial segment, and the other end is connected to the distal end of the fourth axial segment, one end of the fourth circumferential segment is connected to the distal end of the fourth axial segment, and the other end is connected to the distal end of the fifth axial segment.

6. The stent of claim 1, wherein The first axial segment and the second axial segment are parallel or substantially parallel; or the first axial segment, the second axial segment and the first circumferential segment form a triangle.

7. The stent of claim 1, wherein The first axial segment is connected with only two wave-shaped rings located at the proximal end and the distal end; or the first axial segment is connected with the plurality of wave-shaped rings in sequence.

8. The stent of claim 1, wherein: The second axial segment is connected with the plurality of wave-shaped rings in sequence; or the second axial segment is connected with part of the plurality of wave-shaped rings.

9. The stent of claim 1, wherein The wires are two, and the two wires are symmetrically arranged on both sides of the covered stent with the axial center axis of the covered stent as the axis of symmetry. Or, the wires are four, and the four wires are arranged in pairs along the circumference of the covered stent, and symmetrically arranged on both sides of the covered stent with the axial center axis of the covered stent as the axis of symmetry.

10. The stent of claim 1, wherein The plurality of wave-shaped rings and the wires are embedded in the covering film.

11. The stent of claim 10, wherein the stent is a balloon-expandable stent. The covering film comprises an inner layer film, an intermediate layer film and an outer layer film which are stacked in sequence, the wave-shaped rings are embedded between the inner layer film and the intermediate layer film, and the wires are connected with the wave-shaped rings and extend between the intermediate layer film and the outer layer film.

12. The stent of claim 1, wherein: The wave-shaped rings are provided with abutting members, and the wires are abutted by the abutting members.

13. The stent of claim 1, wherein: The wire diameter of the wires ranges from 0.01 to 0.2 mm.

14. The stent of claim 1, wherein: The stent comprises a first segment, a second segment and a transition segment connected with the first segment and the second segment respectively, the outer diameter of the first segment is smaller than the outer diameter of the second segment, the outer diameter of the transition segment gradually increases from one end close to the first segment to one end close to the second segment, and the wires are connected with the stent by double knotting at the transition positions of the first segment and the transition segment and the transition segment and the second segment.

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