Covered stent

Abstract

The present application relates to a kind of film-covered stents, including stent body, film and the anchor portion being arranged on stent body, anchor portion includes several barbs, stent body includes the natural state not by other external force and the compressed state of loading completion, it is characterized in that, during the process that stent body changes from natural state to compressed state, the free end of barb has gap with film, so that the free end of barb as little as possible contact or not contact film surface in loading process, thus it is unnecessary to dull the free end of barb and cause the problem that barb reduces even loses anchoring ability, so as to reduce even avoid the phenomenon that the tip of film-covered stent itself barb damages film in loading process without reducing the anchoring ability of overall stent.

Description

Technical Field

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

[0002] With the rapid increase in the incidence of hypertension, the incidence of arterial-related diseases is also rising significantly, and is projected to grow at a rate exceeding 40% over the next 5 to 7 years. Acute Stanford aortic dissection type A (AADA) is the most common and dangerous aortic emergency in cardiovascular surgery. Without treatment, the mortality rate for AADA within one week is as high as 50-91%. With only conservative medical treatment, the 24-hour mortality rate reaches 20%, and the 48-hour mortality rate can reach 30%. Therefore, AADA, once diagnosed, requires emergency surgical intervention if there are no contraindications. However, even under modern medical conditions, the perioperative mortality rate is as high as 15-35%.

[0003] Currently, minimally invasive endovascular interventional surgery can be used to treat the above-mentioned diseases. Specifically, a covered stent is implanted into the blood vessel to isolate the blood flow from the aortic dissection. During use, the stent is typically first compressed and loaded into a sheath before being transported and released to the designated site. During stent loading, the stent changes from its natural state to a compressed state. As the stent deforms, the covering on its surface wrinkles. Simultaneously, with the relative movement of the sheath and the stent, the covering on the stent is further compressed and accumulated.

[0004] Because existing covered stents generally increase their anchoring ability in human blood vessels by setting barbs, during the loading of the covered stent, the barbs on the stent are also compressed and deformed, bringing them closer to the covered surface. In addition, the compression and accumulation of the covered surface during loading can easily cause the tips of the barbs to puncture the membrane accumulated near the tips of the barbs, thereby compromising the stability of the stent covered surface and causing the covered surface to rupture after implantation. This can easily lead to type III or IV endoleaks, affecting the medical efficacy of the covered stent.

[0005] Furthermore, because this risk occurs during loading, the means of detecting it are limited. Specifically, if it is necessary to detect whether the coating is damaged, the support needs to be released, and after the inspection is completed, the support needs to be reloaded. However, this process introduces a secondary risk to the loading process after the coating inspection is completed, and this risk cannot be avoided by existing detection methods. Summary of the Invention

[0006] Based on this, the present invention provides a coated bracket to solve the problem that the tip of the barbs on the coated bracket itself damages the coating during loading.

[0007] A covered stent, comprising a stent body, a covering film, and an anchoring portion provided on the stent body, the anchoring portion including a plurality of barbs, the stent body including a natural state without other external forces and a compressed state after loading, and characterized in that, during the process of the stent body changing from the natural state to the compressed state, there is a gap between the free ends of the barbs and the covering film.

[0008] In one embodiment, the anchoring portion includes a constraint structure located between the barbs and the covering film.

[0009] In one embodiment, the shape of the constraint structure is columnar, and the length of the constraint structure is between 0.5 times the length of the barbs and 1 time the length of the barbs.

[0010] In one embodiment, the constraint structure is a hollow structure sleeved on the barbs, the distance from the side of the constraint structure away from the covering film to the surface of the barbs is h1, the distance from the side of the constraint structure close to the covering film to the surface of the barbs is h2, and the thickness of the covering film in the first state is h, satisfying h ≤ h1 < 2·h < h2.

[0011] In one embodiment, the anchoring portion includes a barb wave ring and a constraint portion, the constraint portion is located at the root of the barbs, the constraint portion connects the barbs and the barb wave ring, and at least a part of the constraint portion is located between the barbs and the conveying covering film.

[0012] In one embodiment, the barbs include a first side close to the covering film and a second side away from the covering film, and along the proximal end to the distal end direction of the stent body, the first side gradually approaches the second side.

[0013] In one embodiment, the thickness of the proximal end of the barbs is d, the reduction amount of the thickness of the distal end of the barbs relative to the diameter of its proximal end is d1, and the thickness of the covering film in the natural state is h, satisfying 2·h < d1 < 0.5·d.

[0014] In one embodiment, the barbs include a first section and a second section in a stepped shape, the first section and the second section are connected by a transition section, and the first section is farther away from the covering film than the second section.

[0015] In one embodiment, the first section and the second section are parallel to each other, the height difference between the first section and the second section is h3, and the thickness of the covering film in the first state is h, satisfying 2·h < h3; the axial length of the first section along the barbs is L3, and the axial length of the transition section along the barbs is L4, satisfying 1 / 4·L < L4 < 1 / 3·L.

[0016] In one embodiment, the anchoring portion includes a barbed wave ring, wherein the side of the barb closest to the coating forms an angle β with the barbed wave ring, and the angle β gradually increases from the proximal end to the distal end.

[0017] The film-coated support provided by this invention ensures that the free ends of the barbs are kept as far away from the film surface as possible during loading, thus maintaining a gap between the free ends of the barbs and the film surface. This minimizes or eliminates contact between the free ends of the barbs and the film surface during loading, eliminating the need to passivate the free ends of the barbs, which could lead to a reduction or loss of anchoring ability. Consequently, without reducing the overall anchoring ability of the support, the invention reduces or even avoids the phenomenon of the tips of the barbs damaging the film during loading. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a stent in the prior art;

[0019] Figure 2 This is a schematic diagram of the barb structure in the prior art;

[0020] Figure 3 This is a schematic diagram of the sheathing process of a stent in the prior art;

[0021] Figure 4(a) is a schematic diagram of the first state of the stent in the prior art;

[0022] Figure 4(b) is a schematic diagram of the second state of the stent in the prior art;

[0023] Figure 5 This is a schematic diagram of the first state of the barbs in Embodiment 1;

[0024] Figure 6 This is a schematic diagram of the second state of the barbs in Example 1;

[0025] Figure 7 This is a schematic diagram of the first state of the barbs in Example 2;

[0026] Figure 8 This is a schematic diagram of the second state of the barbs in Example 2;

[0027] Figure 9 This is a schematic diagram of the first state of the barbs in Embodiment 3;

[0028] Figure 10 This is a schematic diagram of the second state of the barbs in Example 3;

[0029] Figure 11 This is a schematic diagram of the first state of the barbs in Example 4;

[0030] Figure 12This is a schematic diagram of the second state of the barbs in Example 4;

[0031] Figure 13 This is a schematic diagram of the first state of the barbs in Example 5;

[0032] Figure 14 This is a schematic diagram of the second state of the barbs in Example 5. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0034] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0035] 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 invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] In the field of interventional medical devices, the proximal end of an implant (such as a stent) after deployment is typically defined as the end closer to the heart and the distal end as the end farther from the heart. "Axial" generally refers to the length direction of the implant during delivery, while "radial" generally refers to the direction perpendicular to the implant's "axial" direction. Based on this principle, the "axial" and "radial" of any component of the implant are defined.

[0037] To better illustrate the innovative aspects of this invention, we will first introduce the existing technology.

[0038] Existing technology:

[0039] like Figure 1 As shown in -4 Figure 1 This is a schematic diagram of the structure of the stent 10 in the prior art. Figure 2 This is a schematic diagram of the structure of the barb 102 in the prior art. Figure 3Figure 4 is a schematic diagram of the sheathing process of the stent 10 in the prior art. Figure 4 includes Figure 4(a) and Figure 4(b). Figure 4(a) is a schematic diagram of the first state of the stent 10 in the prior art, and Figure 4(b) is a schematic diagram of the second state of the stent 10 in the prior art.

[0040] The stent 10 is a covered stent, comprising a bare stent 100 and a covering 200. The bare stent 100 is made of a biocompatible material, such as nickel-titanium or stainless steel. Generally, the bare stent 100 includes multiple spaced metal coils. The covering 200 is made of a biocompatible polymer material, such as PTFE, FEP, or PET. To enhance the anchoring ability of the stent 10 after implantation, a barb 102 is typically placed on a metal coil 101 proximal to the bare stent to improve its anchoring ability. The barb 102 has a pointed tip, which facilitates its anchoring in the blood vessel. The extension direction of the barb 102 is inclined relative to the axis of the stent 10, and the angle between the barb 102 and the metal coil 101 is α.

[0041] like Figure 3 As shown, when the support 10 is inserted into the sheath 20, the support 10 will gradually compress into the interior of the sheath 20. Since the distance from the free end of the barb 102 to the longitudinal central axis of the support 10 is slightly greater than the distance from the cover 200 to the longitudinal central axis of the support 10, the free end of the barb 102 is located outside the cover 200.

[0042] The diameter of the support 10 is much larger than the inner diameter of the sheath 20. Therefore, during the process of inserting the support 10 into the sheath 20, the free end of the barb 102 will be squeezed close to the metal bellows 101. Since the support 10 has a tendency to return to its original shape, the surface of the support 10 always abuts against the inner wall surface of the sheath 20, which causes the coating 200 to be squeezed and deformed, forming wrinkles or accumulation. In this case, the distance between the coating 200 and the barb 102 decreases, and the barb 102 will contact or even puncture the coating 200.

[0043] Specifically, as shown in Figures 4(a) and 4(b), the stent is in the first state in Figure 4(a), that is, the free state before insertion into the sheath. At this time, the covering 200 is located on the surface of the bare stent 100, and the extension direction of the barbs 102 makes an angle α with the axial direction. The stent is in the second state in Figure 4(b), that is, the compressed state after insertion into the sheath. When the stent 10 changes from the first state to the second state, the covering 200 wrinkles or accumulates, and the barbs 102 are deformed under pressure. The angle α between the extension direction of their free ends and the axial direction decreases. At this time, the free ends of the barbs 102 contact the covering 200. The free ends of the barbs 102 are very likely to puncture the covering 200, destroying the stability of the covering 200. This risk is uncontrollable, and the rupture of the covering 200 can easily cause type III or IV endoleak in the blood vessel after the implantation surgery, affecting the medical effect of the vascular covered stent.

[0044] Therefore, in order to solve the problems existing in the prior art, the present invention adopts a variety of implementation methods.

[0045] Example 1

[0046] like Figure 5 As shown, Figure 5 This is a schematic diagram of the first state of the barb 112 in Embodiment 1. The barb 112 is disposed on the wave ring 111, and a constraint structure 113 is disposed on the barb 112. The constraint structure 113 is preferably prism in shape, including but not limited to prisms, cylinders, etc. The elasticity of the constraint structure 113 is better than that of the barb 112. The barb 112 passes through the constraint structure 113 and is covered by the constraint structure 113, combined with... Figure 6 , Figure 6 This is a schematic diagram of the second state of the barb 112 in Embodiment 1. When the bracket is inserted into the sheath, the constraint structure 113 on the barb 112 first contacts the covering membrane 210. The constraint structure 113 axially presses the covering membrane 210 near the free end of the barb 112, thereby moving the covering membrane 210 near the free end of the barb 112 away from the free end of the barb 112, so that there is a gap between the barb 112 and the covering membrane 210. The covering membrane 210 in this gap is not at risk of being punctured. At the same time, since one side of the constraint structure 113 is located between the barb 112 and the covering membrane 210, the barb 112 is blocked by the constraint structure 113 during loading, and the barb 112 always maintains a certain distance from the covering membrane 210 during the loading process.

[0047] The length of the barb 112 is L1, and the length of the constraint structure 113 is L2. In order to avoid the constraint structure being too long due to an excessively large L2, which would affect the anchoring effect of the barb, and to avoid the constraint structure being too short due to an excessively small L2, which would prevent it from being effective, the lengths L1 of the barb 112 and L2 of the constraint structure 113 satisfy the condition 0.5·L1<L2<L1 in the preferred state (for ease of distinction, 0.5 times L1 is expressed as 0.5·L1, and the same applies below).

[0048] The distance from the side of the constraint structure 113 furthest from the bevel coil 111 (and also furthest from the coating 210) to the surface of the barb 112 is h1. If h1 is too small, the connection between the constraint structure 113 and the barb 112 is prone to detachment; if h1 is too large, the deformation of the barb 112 after compression is too large, making it easy to puncture the coating 210. The distance from the side of the constraint structure 113 closest to the bevel coil 111 to the surface of the barb 112 is h2. If h2 is too small, the constraint structure 113 cannot function.

[0049] Therefore, the thickness of the coating 210 (thickness refers to the thickness of the coating on the radial section of the support) is denoted as h. In the preferred case, h, h1, and h2 need to satisfy h ≤ h1 < 2·h < h2. In this case, when the sheath of the wave coil 111 is compressed, the constraint structure 113 makes the barb 112 and the coating 210 offset by a clearance space of height h2, so as to prevent the free end of the barb 112 from contacting the coating 210.

[0050] Example 2

[0051] The parts of the covered stent in Embodiment 2 that are the same as those in Embodiment 1 will not be described again here. The main difference between the two is that the covered stent in Embodiment 2 has an added constraint part 123.

[0052] Reference Figure 7-8 As shown, Figure 7 This is a schematic diagram of the first state of the barbs 122 in Embodiment 2. Figure 8 This is a schematic diagram of the second state of the barb 122 in Embodiment 2, where the barb 122 is disposed on the wave coil 121.

[0053] A constraint part 123 is connected to the root of the barb 122. The constraint part 123 is located between the barb 122 and the covering membrane 220 and connects the barb 122 and the wave coil 121. When the bracket is inserted into the sheath, the constraint part 123 prevents the barb 122 from deforming too much, so that the barb 122 will not come into complete direct contact with the covering membrane 220. The barb 122 and the covering membrane 220 have a relatively staggered spatial position, thereby preventing the barb 122 from puncturing the covering membrane 220.

[0054] In another embodiment, the angle between the extension direction of the barb 122 and the corrugated coil 121 is α, and the preferred angle α is 20° < α < 50°. When the angle α is too small, the anchoring force of the barb is small, and the bracket is prone to displacement; when the angle α is too large, during the compression process of the sheath, the corrugated coil will generate large stress at the root of the barb, affecting the quality of the bracket.

[0055] Example 3

[0056] Example 3 selected a new barb structure, such as Figure 9-10As shown Figure 9 is a schematic diagram of the first state of the barb 132 in the third embodiment Figure 10 is a schematic diagram of the second state of the barb 132 in the third embodiment. The barb 132 is arranged on the wave ring 131

[0057] The barb 132 includes a first side close to the wave ring 131 and a second side far from the wave ring 131. At the free end of the barb 132, the extending direction of the second side of the barb 132 remains unchanged, and the first side of the barb 132 gradually approaches the direction of the second side, that is, the distance between the first side and the second side gradually decreases. Overall, it means that the thickness of the barb 132 gradually decreases when approaching its free end. If the cross-section of the anchor barb at a certain place perpendicular to its length direction is circular, the thickness at that place is the diameter of the circle; if the cross-section of the anchor barb at a certain place perpendicular to its length direction is elliptical, the thickness at that place is the short axis of the ellipse; if the anchor barb is a flat structure with a lower surface close to the film and an upper surface far from the film, the thickness at a certain place is the distance between the upper and lower surfaces at that place

[0058] From the perspective of the stent, from the proximal end to the distal end, the first side of the barb 132 gradually approaches the second side. When the stent is inserted into the sheath, the first side of the barb 132 near the root first contacts the film 230, and the first side of the barb 132 near the root axially compresses the film 230, reducing the accumulation degree of the film 230 near the free end of the barb 112. As the free end of the barb 132 is approached, the first side of the barb 132 gradually approaches the second side, resulting in the free end of the barb 132 being further away from the surface of the film 230 compared with the existing barbs, further reducing the risk that the free end of the barb 132 pierces the film 230

[0059] The root diameter of the barb 132 is d, the reduction amount of the thickness of the free end of the barb 132 relative to its root thickness is d1, and the thickness of the film 230 is h. Preferably, 2·h < d1 < 0.5·d. If the reduction amount d1 of the thickness of the free end of the barb 132 relative to its root thickness is too small, it is difficult for the free end of the barb 132 to avoid the film, resulting in the free end of the barb 132 piercing the film. If d1 is too large, the tip strength of the barb 132 is insufficient. After the stent is implanted into the human body and released, the anchoring strength of the barb 132 is insufficient, and under the impact of blood, the stent is prone to position deviation, affecting the medical effect

[0060] In another embodiment, the side of the barb 132 near and facing the first side of the coating includes a continuous first surface near the root of the barb 132 and a second surface away from the root of the barb 132. The first surface is planar, and the second surface is curved, such that the first side of the barb 132 gradually approaches the second side from the root of the barb 132 toward the free end of the barb 132. That is, the first surface is parallel to the surface of the second side, and the second surface gradually approaches the surface of the second side toward the free end of the barb 132. To ensure a smooth transition between the first and second surfaces, the first and second surfaces are preferably tangent.

[0061] The first and second surfaces on the first side of the barb 132 are continuous and tangent, with a smooth transition between them. This embodiment ensures that there is a gap between the cover 230 and the free end of the barb 132, thus avoiding the formation of sharp edges at the transition between the arc surface and the bottom surface that could scratch or damage the cover 230, thereby preventing type III endoleak after the stent is implanted in the human body.

[0062] Example 4

[0063] Example 4 selected a new barb structure, such as Figure 11-12 As shown, Figure 11 This is a schematic diagram of the first state of the barbs 142 in Embodiment 4. Figure 12 This is a schematic diagram of the second state of the barb 142 in Embodiment 4. The barb 142 is disposed on the wave coil 141.

[0064] The parts of the covered support in Embodiment 4 that are the same as those in Embodiment 3 will not be described again here. The main difference between the two is that the barb 142 in Embodiment 4 is stepped, and the free end (tip) of the barb 142 is located on a step away from the wave ring 141, so that the end of the barb 142 is offset upward as a whole, avoiding contact between the tip of the barb 142 and the covered film 30, and preventing the tip of the barb 142 from puncturing the covered film 240.

[0065] The barb 142 includes a first segment m, a second segment p, and a transition segment n. The first segment m is the tip segment of the barb, the second segment p is the starting segment of the barb, and the transition segment n is a bending and misalignment transition segment used to connect the first segment m and the second segment p.

[0066] When the support is inserted into the sheath, the second segment p of the barb 142 contacts the covering membrane 240 first. The second segment p of the barb 142 axially compresses the covering membrane 240, reducing the degree of accumulation of the covering membrane 240 at the free end of the barb 142. Meanwhile, the first segment m is offset outward by a distance (h3) relative to the second segment p. When the second segment p contacts the covering membrane 240, there is a gap between the first segment m and the covering membrane 240, which further reduces the risk of the free end of the barb 132 piercing the covering membrane 230.

[0067] In this implementation, after the barbs 142 are bent twice, the first segment m and the second segment p of the barbs 132 remain parallel to each other and are offset by a distance h3. The thickness of the coating 240 remains h. Therefore, the relationship between h3 and the thickness of the coating 240 should satisfy: 2·h < h3. If h3 is too small, the tip of the barb 142 will have difficulty avoiding the coating 240, and the tip of the barb 142 may easily puncture the surface of the coating 240, causing internal leakage after the stent is released.

[0068] The relationship between the length L3 of the first segment m and the length L of the barb 142 should satisfy: 1 / 3L < L3 < 0.5L. If L3 is too short, the anchoring performance of the barb will be reduced; if L3 is too long, it will inevitably shorten the length of the barb root. When the barb 142 is bent for the first time, the second segment p will generate greater stress, affecting the service life and quality of the wave coil.

[0069] The relationship between the length L4 of the transition segment n and the length L of the barb 142 should satisfy: 1 / 4·L < L4 < 1 / 3·L. If L4 is too long, the lengths of the first segment m and the second segment p of the barb 142 will be shortened, resulting in greater stress on the second segment p of the barb 142 and reducing the anchoring performance of the first segment m. If L4 is too short, the barb 142 will bend twice in a short distance, and there will be greater stress in the bending and misalignment transition zone n of the barb 142. During the compression process, the barb 142 is prone to breakage.

[0070] Example 5

[0071] Example 5 selected a new barb structure, such as Figure 13-14 As shown, Figure 13 This is a schematic diagram of the first state of the barbs 152 in Embodiment 5. Figure 14 This is a schematic diagram of the second state of the barb 152 in Embodiment 5, where the barb 152 is disposed on the wave coil 151.

[0072] The parts of the covered stent in Embodiment 5 that are the same as those in Embodiment 3 will not be described again here. The main difference between the two is that the extension direction of the free end of the barb 152 in Embodiment 5 is further offset away from the wave ring. Specifically, the barb 152 includes a root connected to the wave ring 151 and a free end. The direction in which the barb 152 extends toward the free end at the root position is the first direction, and the direction in which the barb 152 extends toward the free end near the free end position is the second direction. The straight lines containing the first direction and the second direction intersect.

[0073] It should be noted that there is a first direction and at least one second direction, and for any second direction, the angle formed by the second direction and the coating 250 is greater than the angle formed by the first direction and the coating 250.

[0074] Let the value in the second direction be denoted as β. When the β angle is too small, the anchoring force of the waveguide is weak, and displacement is likely to occur after the covered stent is released and implanted into the human body. When the β angle is too large, significant stress will be generated at the root of the barb 152 and at the bend of the barb 152 during the compression process of the sheath, affecting the quality of the waveguide. Therefore, preferably, β satisfies 20° < β < 50°.

[0075] When the support is inserted into the sheath, the root of the barb 152 contacts the covering membrane 250 first. The root of the barb 152 axially presses the covering membrane 240, reducing the degree of accumulation of the covering membrane 250 at the free end of the barb 152. Since there is a gap between the first segment m and the covering membrane 240 when the second segment p contacts the covering membrane 240, the risk of the free end of the barb 132 piercing the covering membrane 230 is further reduced.

[0076] In another embodiment, the angle β between the free end tangent of the barb 152 and the wave loop 151 gradually increases from the proximal end to the distal end.

[0077] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A covered stent, comprising a stent body, a covering, and an anchoring portion disposed on the stent body, the anchoring portion comprising a plurality of barbs, the stent body comprising a natural state unaffected by other external forces and a compressed state after loading, characterized in that, The anchoring portion includes a restraining structure, at least a part of which is located between the barbs and the film, so that there is a gap between the free ends of the barbs and the film during the process of the stent body changing from the natural state to the compressed state.

2. The covered stent according to claim 1, characterized in that, The restraining structure is located between the barbs and the film. The side of the barbs close to and facing the first side of the film includes a continuous first surface close to the root of the barbs and a second surface away from the root of the barbs. The first surface is a plane, and the second surface is a curved surface.

3. The covered stent according to claim 1, characterized in that, The shape of the restraining structure is columnar, and the length of the restraining structure is between 0.5 times the length of the barbs and 1 time the length of the barbs.

4. The covered stent according to claim 1, characterized in that, The restraining structure is a hollow structure sleeved on the barbs. The distance from the side of the restraining structure away from the film to the surface of the barbs is h1, the distance from the side of the restraining structure close to the film to the surface of the barbs is h2, and the thickness of the film in the natural state is h, satisfying h ≤ h1 < 2·h < h2.

5. The covered stent according to claim 1, characterized in that, The anchoring portion includes a barb wave ring and a restraining portion. The restraining portion is located at the root of the barbs, and the restraining portion connects the barbs and the barb wave ring.

6. The covered stent according to claim 1, characterized in that, The barbs include a first side close to the film and a second side away from the film. Along the direction from the proximal end to the distal end of the stent body, the first side gradually approaches the second side.

7. The covered stent according to claim 6, characterized in that, The thickness of the proximal end of the barbs is d, and the reduction amount of the thickness of the distal end of the barbs relative to the diameter of its proximal end is d1. The thickness of the film in the natural state is h, satisfying 2·h < d1 < 0.5·d.

8. The covered stent according to claim 1, characterized in that, The barbs include a first section and a second section in a stepped shape, and the first section and the second section are connected by a transition section. The first section is farther from the film than the second section.

9. The covered stent according to claim 8, characterized in that, The first section and the second section are parallel to each other, and the height difference between the first section and the second section is h3. The thickness of the film in the natural state is h, satisfying 2·h < h3; the axial length of the first section along the barbs is L3, and the axial length of the transition section along the barbs is L4. The size relationships between L3 and L4 and the length L of the barbs should respectively satisfy 1 / 3L < L3 < 0.5L and 1 / 4·L < L4 < 1 / 3·L.

10. The covered stent according to claim 8, characterized in that, The anchoring portion includes a barb wave ring. An included angle β is formed between the side of the barbs close to the film and the barb wave ring, and the included angle β gradually increases from the proximal end to the distal end.

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