Stent graft

Abstract

The coated stent of the present invention includes a main body portion, the interior of the main body portion is hollow and has openings at both ends; a skirt portion, the skirt portion is sleeved on the outside of the main body portion, the skirt portion includes a folding section and a connecting section, one end of the connecting section is connected to the main body portion and forms an opening toward the proximal end, the folding section includes a connecting end, the connecting end of the folding section is connected to the other end of the connecting section, and the other end of the folding section opposite to the connecting end forms a free end; the folding section extends toward the distal end and forms an opening toward the distal end between the folding section and the connecting section, the folding section includes a first support member and a first coating provided on the first support member, the average circumferential coating amount of the first coating near the free end is smaller than the average circumferential coating amount near the connecting end. According to the coated stent of the present invention, since the average circumferential coating amount of the first coating near the free end is smaller than the average circumferential coating amount near the connecting end, the folding section is easy to fold, which effectively ensures the success rate of the stent positioning during surgery.

Description

Technical Field

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

[0002] In recent years, for special lesion sites such as the aortic arch, celiac artery trunk, bilateral renal arteries or superior mesenteric artery, covered stents are generally used to intervene in the blood supply of arterial branch vessels to achieve the effect of treatment and cure.

[0003] Endovascular grafting with aortic stent grafts has been widely used for lesions such as thoracic and abdominal aortic aneurysms and dissections. Its proven efficacy, minimal invasiveness, rapid recovery, and minimal complications have made it a first-line treatment. When using endovascular repair to treat aortic dissections or aortic aneurysms, large stent implantation often presents difficulties due to insufficient proximal landing zone length. In these situations, experienced surgeons opt to increase the proximal landing zone of the large stent by creating a landing zone that covers the branch vessels. To restore branch blood supply, the chimney technique or in situ fenestration is the most common technique. In particular, the fenestration technique involves creating a desired pore in the stent graft during surgery, often using laser or mechanical means. One or more branch stents are then delivered to this pore and docked with the main stent. This treatment approach overcomes the anatomical dependence of the human branch vessels.

[0004] In order to avoid internal leakage after the branch is implanted at the in situ fenestration position, a skirt can be set on the outside of the branch stent. However, how to ensure the sealing and anchoring performance of the skirt part after the branch is implanted has a certain degree of randomness. For example, the skirt cannot fit well with the inner surface of the main stent or the skirt cannot be well unfolded or folded, which affects the use effect of the branch stent. Summary of the Invention

[0005] The present invention provides a stent graft, comprising:

[0006] a main body portion, wherein the interior of the main body portion is hollow and has openings at both ends;

[0007] A skirt portion, wherein the skirt portion is sleeved on the outside of the main body portion, the skirt portion includes a folding section and a connecting section, one end of the connecting section is connected to the main body portion and forms an opening toward the proximal end, the folding section includes a connecting end, the connecting end of the folding section is connected to the other end of the connecting section, and the other end of the folding section opposite to the connecting end forms a free end; in a natural state, the folding section extends toward the distal end and forms an opening toward the distal end between the folding section and the connecting section, the folding section includes a first support member and a first coating provided on the first support member and connected to the first support member, the average circumferential coating amount of the first coating near the free end is smaller than the average circumferential coating amount near the connecting end.

[0008] In one embodiment, a thickness of the first coating near the free end is smaller than a thickness of the first coating near the connecting end.

[0009] In one embodiment, the thickness of the first coating gradually decreases along a direction from the connecting end to the free end of the folded segment.

[0010] In one embodiment, the first support member and the first coating are on the same plane, and the first support member includes a plurality of support rods. Among the plurality of support rods, two adjacent support rods are connected at one end away from the connecting section to form the free end, and the enclosed area between the two adjacent support rods is larger than the area of ​​the first coating located between the two adjacent support rods.

[0011] In one embodiment, in the length extension direction of the folded segment, the length dimension of the first support member is greater than the length dimension of the first covering film, and the free end of the first support member is exposed.

[0012] In one embodiment, the support rod includes a long support rod and a short support rod, two adjacent short support rods are connected to form a low wave peak, and two adjacent long support rods are connected to form a high wave peak, the low wave peaks and the high wave peaks are arranged alternately, the low wave peaks are closer to the connecting section than the high wave peaks, and the short support rods are completely covered by the first film, and the long support rods are partially exposed.

[0013] In one embodiment, the first support member and the first coating are not completely in the same plane, and on the first coating near the free end, at least a portion of the first coating is convex outward or concave inward relative to the plane where the first support member is located.

[0014] In one embodiment, the first coating is formed by expanding the original coating between two adjacent support rods, and the surface area of ​​the first coating is greater than the surface area of ​​the original coating.

[0015] A stent graft, comprising:

[0016] a main body portion, wherein the interior of the main body portion is hollow and has openings at both ends;

[0017] A skirt portion, the skirt portion is sleeved on the outside of the main body portion, the skirt portion includes a folding section and a connecting section, the distal end of the connecting section is connected to the outer surface of the main body portion, and the proximal end of the folding section is connected to the proximal end of the connecting section; the folding section includes a first support member, and the connecting section includes a second support member and a coating, the coating is arranged on the surface of the second support member and connected to the second support member, in a natural state, the proximal end of the first support member is connected to the proximal end of the second support member, and the distal end of the first support member extends toward the distal end to form a free end; the coating extends from the distal end of the second support member to the proximal end of the second support member and does not exceed the proximal end of the first support member.

[0018] In one embodiment, in a natural state, the projection of the free end of the folded section on the outer surface of the main body coincides with the connection point between the connecting section and the outer surface of the main body, or the projection of the free end of the folded section on the outer surface of the main body is closer to the proximal end of the main body than the connection point between the connecting section and the outer surface of the main body.

[0019] According to the coated stent of the present invention, when it is necessary to dock with the window of the main stent in the blood vessel, the distal end of the main body of the coated stent is extended to the outside of the main stent through the window. As the main body is passed through, the folded section of the skirt contacts the inner wall of the window. Since the average circumferential coating amount of the first coating near the free end is smaller than the average circumferential coating amount near the connecting end, or the coating extends from the distal end of the second support member to the proximal end of the second support member and does not exceed the proximal end of the first support member, the folded section is easy to fold, so that the skirt is automatically flipped by the external force after being formed, which effectively ensures the success rate of the stent positioning during the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference numerals are used throughout the accompanying drawings to denote the same components.

[0021] Figure 1 This is a schematic structural diagram of the stent graft in the natural state according to the first embodiment;

[0022] Figure 2 for Figure 1 A schematic structural diagram of the skirt portion of the middle stent graft when the folded section is in a folded state;

[0023] Figure 3 Schematic diagram of the structure of another example of a stent graft in the first embodiment;

[0024] Figure 4 It is a structural schematic diagram of the present invention when the stent graft and the main stent are in an anchored state;

[0025] Figure 5 This is a schematic structural diagram of the stent graft in the natural state according to the second embodiment;

[0026] Figure 6 for Figure 5 A schematic structural diagram of the skirt portion of the middle stent graft when the folded section is in a folded state;

[0027] Figure 7 Schematic diagram of the structure of the folding section in a folded state according to another example of the second embodiment;

[0028] Figure 8 This is a schematic structural diagram of the stent graft in a natural state according to the third embodiment;

[0029] Figure 9 for Figure 8 A schematic structural diagram of the skirt portion of the middle stent graft when the folded section is in a folded state;

[0030] Figure 10 This is a schematic structural diagram of the stent graft in a natural state according to the fourth embodiment;

[0031] Figure 11 for Figure 10 Schematic diagram of the partial cross-section structure of the middle folding section;

[0032] Figure 12 This is a partial cross-sectional structural diagram of another example of the folding section in the fourth embodiment.

[0033] It should be noted that the drawings of the present invention only show some support parts for illustration. The support parts are not the main focus of the present invention. Those skilled in the art can select and design the specific structure and parameters of the support parts according to actual needs. DETAILED DESCRIPTION

[0034] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0035] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0036] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0037] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," and the like. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "below" another element or feature would then be oriented as "above" or "above" another element or feature. Thus, the example term "below" can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly.

[0038] To more clearly describe the structure of this application, the terms "proximal" and "distal" are defined herein as commonly used in the medical device field. Specifically, "distal" refers to the end from which blood flows out, and "proximal" refers to the end from which blood flows in. For the present invention, blood flows into the stent graft from the proximal end and out from the distal end. "Axial" refers to the longitudinal direction, and "radial" refers to the direction perpendicular to the "axial" direction.

[0039] The covered stent of the present invention can be used in conjunction with the main stent implanted in the aorta, thereby re-establishing the blood supply of the branch vessels.

[0040] Implementation Method 1

[0041] Combine Figures 1 to 2 As shown, the stent graft 100 of this embodiment includes a main body 10 and a skirt 20. The main body 10 is hollow inside and has openings at both ends. The skirt 20 is sleeved on the outside of the main body 10. The skirt 20 includes a folding section 21 and a connecting section 22. In a natural state, the distal end of the connecting section 22 is connected to the outer surface of the main body 10 and forms a first opening 23 facing the proximal end. The folding section 21 includes a connecting end, through which the folding section 21 is connected to the proximal end of the connecting section 22 in a foldable manner. The other end of the folding section 21 opposite the connecting end is a free end. In a natural state, the folding section 21 extends toward the distal end, thereby forming a second opening 24 facing the distal end between the folding section 21 and the connecting section 22. In the delivery state, the stent graft is compressed in the sheath, and the folding section and the connecting section are both in contact with the outer surface of the main body, and the free end of the folding section extends toward the proximal end, that is, the opening formed by the folding section and the outer surface of the main body and the first opening formed by the connecting section are both facing the proximal end.

[0042] It is understood that, because the connecting segment is connected to the main body at only one end, the connecting segment can be folded relative to the main body with the connection point as the origin under the action of an external force. For example, the end of the connecting segment connected to the folding portion can be folded from the proximal end to the distal end, so that the proximal opening formed by the connecting segment also becomes a distal opening. Therefore, the above description only describes the relative structure and positional relationship of the various components of the stent graft in its natural state.

[0043] The folding section 21 includes a first support member 211 and a first coating 212. The first coating 212 is disposed on the surface of the first support member 211 and is connected to the first support member 211. The thickness of the first coating 212 gradually decreases from the end of the folding section 21 where it connects to the connecting section 22 to the free end of the folding section 21. This gradually reduces the circumferential restraining force exerted by the first coating on the first support member in this direction, allowing the free end of the folding section 21 to fold from the delivery state toward the distal end and return to its natural state when no external force is applied.

[0044] It can be understood that in other embodiments, the first coating may also change suddenly along the direction from the distal end where the folding section is connected to the connecting section to the free end of the folding section. For example, the first coating is thinner only in the portion close to the free end of the folding section. In this way, since the thickness of the first coating close to the free end is thinner, the circumferential restraint force on the free end of the first support member is reduced, and the folding portion can easily fold from the conveying state to the natural state.

[0045] like Figure 1 As shown, in the natural state, the surface of the folded section 21 is parallel or approximately parallel to the surface of the main body 10, that is, in the natural state, the folded section 21 can extend along the length direction of the main body, or can extend inward toward the direction close to the outer surface of the main body, or extend outward toward the direction away from the outer surface of the main body. When the folded section 21 is no longer constrained by the radial direction of the sheath, the folded section 21 gradually folds toward the distal end with the end connected to the connecting section (hereinafter referred to as the "connecting end") as the origin, and finally forms the following Figure 2 Anchored state shown.

[0046] like Figure 1 and Figure 2 As shown, the connecting section 22 has a trumpet-shaped structure and includes a second support member 221 and a second covering 222. The second covering 222 is disposed on the surface of the second support member 221, and the connecting section 22 is connected to the main body 10 via the second covering 222. The first covering 212 increases the anchoring area of ​​the folded section 21 and, together with the second covering 222, prevents internal leakage.

[0047] The first support member 211 and the second support member 221 can each include at least one wave coil, and the two can be connected by the wave coils hanging on each other. In this embodiment, the first support member includes a plurality of support rods 2111, and among the plurality of support rods 2111, one end of two adjacent support rods 2111 is connected to form a wave crest, and the other end of two adjacent support rods 2111 is connected to form a wave trough, thereby forming a wave structure, in which the plurality of wave crests can be regarded as a plurality of free ends, and the plurality of wave troughs are close to the connecting section. Alternatively, the first support member 211 and the second support member 221 can also be an integrated structure (i.e., the first support member and the second support member are different parts of the same wave coil). In this case, the first support member can be folded relative to the second support member when not subjected to external force by a shaping method. In addition, the second support member 221 can also be connected to the main body by sewing, so that the second support member 221 is trumpet-shaped after being connected to the main body 10.

[0048] In the natural state, the folding section 21 is Figure 1The width in the horizontal direction is L1. The length of the connecting section 22 in its own extension direction is L2, preferably 1 cm ≤ L2 + L1 ≤ 2 cm, so as to ensure the anchoring performance and anti-endoleak performance of the skirt while reducing the obstruction of the skirt on the adjacent branch blood vessel opening after the stent graft 100 is implanted into the main stent. In addition, when comprehensively considering the anti-displacement performance and sealing performance of the coated stent 100, after the coated stent 100 is implanted into the main body stent, the connecting section 22 is usually in contact with the window of the main body stent. During the folding process of the folding section, after the free end of the folding section contacts the inner wall of the main body stent, the folding section stops folding due to the obstruction of the inner wall of the main body stent. That is to say, when the coated stent 100 is implanted into the main body stent and cooperates with the main body stent, the folding section does not necessarily completely return to its natural state. In order to increase the contact area between the folding section and the inner wall of the main body stent as much as possible, it is preferred that in the natural state, the projection of the free end of the folding section on the outer surface of the main body coincides with the connection point between the connecting section and the outer surface of the main body, or the projection of the free end of the folding section on the outer surface of the main body is closer to the proximal end of the main body than the connection point between the connecting section and the outer surface of the main body. Figure 2 Another preferred state diagram of the folded segment after implantation in cooperation with the main stent is shown, wherein the folded segment 21 is substantially in contact with the inner wall of the main stent and is substantially perpendicular to the axial direction of the main body.

[0049] In this embodiment, end a of the folding segment 21 (i.e., the distal end of the folding segment 21 in its natural state) is a free end, and end b of the folding segment 21 (i.e., the proximal end of the folding segment 21 in its natural state) is connected to the connecting segment 22. The distal end of the connecting segment 22 is connected to the outer surface of the main body 10, thereby achieving mutual fixation between the skirt portion 20 and the main body 10. The thickness of the first coating 212 near end a can be selected to range from 0.02mm to 0.05mm, and the thickness of the first coating 212 near end b can range from 0.06mm to 0.12mm. The thickness of the first coating 212 gradually increases from end a toward end b. Because the thickness of the first coating 212 near the free end of the folding segment 21 is relatively small, the circumferential restraining force on the folding segment 21 is reduced, ensuring that the folding segment 21 can automatically flip from the delivery state to the natural state when not subjected to external forces, thereby achieving mutual anchoring between the coated stent 100 and the main stent 200, thereby establishing reliable blood flow to the branch vessels.

[0050] In this embodiment, the first coating of the folded section 21 and the first support member are basically in the same plane, and the first support members 211 are all covered by the first coating 212, that is, the enclosed area between two adjacent support rods is equal to the area of ​​the first coating located between the two adjacent support rods, and the edge of the free end of the first support member coincides with the edge of the first coating, wherein the first coating 212 is arranged in an annular shape, and the radial length of the first coating 212 is equal to the radial length of the first support member 212, thereby maximizing the effective covering area of ​​the first coating 212, increasing the anchoring area between the folded section 21 and the main support 200, and thus improving the fixing effect of the coated support 200. Figure 3 As shown, in other examples of this embodiment, when the first coating and the first support member are basically in the same plane, the first coating 212 between any adjacent free ends on the first support member 211 is curved toward the proximal end in an arc shape, that is, the average circumferential coating amount near the free end of the first support member is smaller than the average circumferential coating amount near the connecting end between the first support member and the connecting section. The average circumferential coating amount can be defined as the average coating amount per unit area on any annular surface. The coating amount can be determined by the degree of coating and the coating thickness, that is, for the case of the same coating thickness and complete coating, the coating amount per unit area is equal; and for the case of the same coating thickness but partially uncoated, the average circumferential coating amount of the annular portion including the uncoated portion is smaller than the average circumferential coating amount of the fully coated portion. Using Figure 3 The illustrated design also fully encapsulates the first support member 211, but reduces the average circumferential coating amount near the free end of the first support member. This reduces the circumferential constraint force exerted by the first coating on the adjacent free ends of the first support member, while also ensuring the anchoring area and anchoring force of the folded section 21 after folding, thereby ensuring the anchoring effect. It will be appreciated that in this example, the thickness of the first coating can be uniform, or the thickness of the first coating near the free end can be thinner than the thickness of the first coating near the connection end.

[0051] like Figure 4As shown, when the stent graft 100 according to the present invention needs to be docked with the main stent 200 in the aorta 300, the main stent 200 is fenestrated, and then the stent graft 100 is implanted through the branch vessel 400 to cooperate with the main stent 200. Specifically, after the main stent 200 is fenestrated, the proximal end of the main body 10 of the stent graft 100 is inserted through the fenestration into the interior of the main stent 200 through the branch vessel 400, thereby connecting the main stent 200 and the branch vessel 400 through the openings at both ends of the main body 10 to maintain unobstructed blood flow in the branch vessel 400. During the implantation of the stent graft 100, as the sheath in the delivery system is withdrawn, the folding section is gradually released and folded. Since the thickness of the first coating 212 along the folding section 21 decreases from the end where the folding section is connected to the connecting section toward the free end, the first coating 212 near the free end has a smaller binding force on the first support member 211, making it easier to fold, thereby achieving the automatic folding of the folding section 21 of the skirt portion 20 when not subjected to external force. In addition, during the withdrawal of the sheath, the squeezing action of the end of the sheath can also assist in folding the folding section 21, while increasing the size of the second opening 24 and the contact area between the folding section 21 and the inner wall of the main stent at the window position, that is, increasing the contact area of ​​the stent graft 100 at the window position, thereby improving the sealing effect and fixing effect of the stent graft 100 at the window position, preventing the stent graft 100 from displacement, effectively ensuring the success rate of stent positioning during surgery, and reducing safety hazards caused by stent displacement. In the process of the folding section returning to the natural state from the conveying state, when the presence of the first coating is not considered, the distance between the adjacent support rods on the first support member of the folding section changes, wherein, when the folding section is perpendicular to the axis of the main body (i.e. Figure 2 As shown in the state), the distance between the support rods is the largest, as long as the folding section can be folded from the conveying state to Figure 2 In the transition state shown, the folding section can be folded smoothly. Therefore, by reducing the thickness of the first coating near the free end of the folding section, the circumferential restraining force between adjacent free ends is reduced, ensuring that the folding section can be folded smoothly.

[0052] Implementation Method 2

[0053] Combine Figure 5 and Figure 6As shown, the overall structure of the stent graft 100 in this embodiment is substantially identical to that in the first embodiment, except that the first coating 212 of the folding section 21 in this embodiment does not completely cover the first support member. The free end of the first support member 211 is exposed outside the first coating 212. Along the length of the folding section, the length of the first coating 212 is less than the length of the first support member 211, meaning that the first support member 211 includes an exposed portion near the free end. Consequently, the average circumferential coating amount near the free end of the first support member is still less than the average circumferential coating amount near the connection end between the first support member and the connecting section. Furthermore, for the exposed free ends of the first support member, there is no circumferential constraint of the coating between adjacent free ends, making it easier for the folding section to fold from the delivery state to the natural state. Preferably, the radial length of the first coating 212 is half the radial length of the first support member 211, meaning that the half of the length of the first support member 211 near the free end is free of the coating structure. Such a design can reduce the restraining force of the first covering film 212 on the first supporting member 211 , thereby better facilitating the folding of the folding section.

[0054] The first coating 212 is Figure 5 The width in the middle horizontal direction is L3, and the length of the connecting section 22 in its own extension direction is L4, preferably 1 cm ≤ L4 + L3 ≤ 2 cm, so as to ensure the anchoring performance and anti-internal leakage performance of the skirt while reducing the obstruction of the adjacent branch blood vessel openings by the skirt after the coated stent 100 is implanted into the main stent. In addition, as in the above embodiment, it is preferred that in the natural state, the projection of the free end of the folded section on the outer surface of the main body coincides with the connection point between the connecting section and the outer surface of the main body, or the projection of the free end of the folded section on the outer surface of the main body is closer to the proximal end of the main body than the connection point between the connecting section and the outer surface of the main body. In this embodiment, the thickness of the first coating 212 may also gradually increase from end a toward end b. In other examples of this embodiment, the thickness of the first coating may also be uniform.

[0055] like Figure 6 As shown, on the first support member 211, an area c is enclosed between the free end of the first support member 211 and the end of the first coating 212 away from the connecting section. In other embodiments, a first coating 212 may also be provided in the area c. The first coating 212 in the area c and the first coating 212 at the proximal end of the folding section 21 jointly fully cover the area enclosed by the first support member 211, thereby further increasing the anchoring area of ​​the folding section 21 and ensuring the anchoring force without affecting the folding performance of the folding section 21.

[0056] like Figure 7As shown, in other examples of this embodiment, the support rod 2111 includes multiple long support rods 2112 and short support rods 2113. The length of the short support rod 2113 is less than the length of the long support rod 2112. Two adjacent short support rods form a low wave peak, and two adjacent long support rods form a high wave peak. The high wave peak and the low wave peak are arranged alternately, and the low wave peak is closer to the connecting section than the high wave peak, and the area where the short support rod 2113 is located is provided with a first coating 212.

[0057] The length of the short support rod 2112 is denoted as m, and the length of the short support rod 2113 is denoted as n, where m>n. The coverage area of ​​the first coating 212 is such that it just covers the end surface of the short support rod 2113. Preferably, m≥2n. This ensures both the support and sealing performance of the folded section. The addition of the short support rod 2113 further enhances the support force of the folded section 21 and the anchoring force between the folded section 21 and the anchored area. Furthermore, the folding section 21 in this example can also be provided with a first coating 212 in an area c enclosed by the portion of the first support member 211 extending outside the first coating 212. The first coating 212 in the area c and the first coating 212 at the proximal end of the folding section 21 can jointly fully cover the area enclosed by the first support member 211, thereby further increasing the anchoring area of ​​the first coating 212 in the folding section 21, reducing the local pressure of the folding section on the main support, and ensuring the anchoring force without affecting the folding performance of the folding section 21.

[0058] Implementation Method 3

[0059] Combine Figure 8 and Figure 9As shown, the stent graft 100 in this embodiment includes a main body 10 and a skirt 20. The main body 10 is hollow inside and open at both ends. The skirt 20 is sleeved on the outside of the main body 10. The skirt 20 includes a folded section 21 and a connecting section 22. The distal end of the connecting section 22 is connected to the main body 10 and forms a first opening 23 facing the proximal end. The folded section 21 is connected to the proximal end of the connecting section 22 in a foldable manner, and a second opening 24 facing the distal end is formed between the folded section 21 and the connecting section 22. The connecting section 22 includes a second support member 221 and a coating 222. The coating 222 is disposed on the surface of the second support member 221 and is connected to the second support member 221. The folding section 21 includes a first support member 211. In its natural state, the proximal end of the first support member 211 is connected to the proximal end of the second support member 221, and the distal end of the first support member 211 extends distally to form a free end. The coating 222 extends from the distal end of the second support member 221 to the proximal end of the second support member 221, but does not extend beyond the proximal end of the first support member 211. This embodiment differs from the first embodiment in that the first support member 211 of the folding section 21 is not provided with a first coating, i.e., the first support member 211 is completely exposed. The absence of the first coating leaves the first support member 211 completely unconstrained by the coating, making it easier to fold. In other examples, the first coating 211 may also be provided in the area c between the free end of the first support member 211 and the end of the second coating away from the outer surface of the main body tube of the folding section 21, and connected with the coating 222 on the connecting section 22 to form a coating area. The added coating in the area c can prevent internal leakage between the first support member 211 and the second support member 221, and at the same time increase the anchoring area between the folded folding section 21 and the anchored area, thereby increasing the anchoring force without affecting the folding performance of the folding section 21.

[0060] In addition, similar to the above embodiment, preferably, in a natural state, the projection of the free end of the folded section on the outer surface of the main body coincides with the connection point between the connecting section and the outer surface of the main body, or the projection of the free end of the folded section on the outer surface of the main body is closer to the proximal end of the main body than the connection point between the connecting section and the outer surface of the main body.

[0061] Implementation Method 4

[0062] Combine Figures 10 to 12 As shown, the overall structure of the stent graft 100 in this embodiment is basically the same as that in the first embodiment. The difference from the first embodiment is that the first coating 212 between any two adjacent crests on the first support member 211 in this embodiment is convex outward or concave inward relative to the plane formed by the two adjacent crests, that is, the first coating is connected to the first support member, but the two are not completely in the same plane. Figure 11As shown, in this embodiment, the first coating 212 between endpoints A and B of adjacent support rods of the first support member 211 has a raised surface facing outward, forming end a. Due to the raised surface, the length of the first coating between adjacent support rods near the free end of the first support member is longer than the linear distance between the adjacent support rods. This reduces the circumferential restraining force exerted by the first coating between the support rods, making the raised first coating 212 in this embodiment easier to fold than the flat first coating 212.

[0063] like Figure 12 As shown, in other examples, the first coating 212 between the end points A and B of two adjacent support rods on the first support member 211 can also be recessed toward the outer surface to form end a.

[0064] It is understandable that, in other examples, a portion of the first covering film between adjacent support rods may be concave, a portion may be convex, and a portion may be in the same plane as the support rods.

[0065] It is understood that when preparing the folded section 21 of this embodiment, in order to achieve a concave or convex structure in the first coating 212 of the folded section 21, the original coating can be expanded based on its production (i.e., after the coating is completed, the original coating between the support members is in a tensioned state). This slightly deforms the original coating to form a first coating, and the surface area of ​​the first coating is larger than that of the original coating. Simultaneously, the thickness of the first coating 212 between endpoints A and B is reduced, i.e., the average circumferential thickness of the first coating 212 near the free end of the folded section 21 is smaller than the average circumferential thickness of the first coating 212 in the remaining portion of the folded section 21, thereby forming a convex or concave structure. The actual length of the distal edge of the first coating 212 between endpoints A and B is greater than the straight-line distance between endpoints A and B. It is understood that before the expansion operation is performed on the first coating, the coating thickness can be uniform or gradually decrease from the free end to the connection. It is also understandable that the convexity or concavity of the first coating can also be achieved by cooperating with other molds, that is, after the coating is completed, the thickness of the first coating is still uniform.

[0066] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A stent graft, characterized in that: include: a main body portion, wherein the interior of the main body portion is hollow and has openings at both ends; A skirt portion, wherein the skirt portion is sleeved on the outside of the main body portion, the skirt portion includes a folding section and a connecting section, one end of the connecting section is connected to the main body portion and forms an opening toward the proximal end, the folding section includes a connecting end, the connecting end of the folding section is connected to the other end of the connecting section, and the other end of the folding section opposite to the connecting end forms a free end; in a natural state, the folding section extends toward the distal end and forms an opening toward the distal end between the folding section and the connecting section, the folding section includes a first support member and a first coating provided on the first support member and connected to the first support member, the average circumferential coating amount of the first coating near the free end is smaller than the average circumferential coating amount near the connecting end.

2. The stent graft according to claim 1, wherein: The thickness of the first coating near the free end is smaller than the thickness of the first coating near the connecting end.

3. The stent graft according to claim 2, wherein: The thickness of the first coating gradually decreases along a direction from the connecting end to the free end of the folded segment.

4. The stent graft according to any one of claims 1 to 3, characterized in that: The first support member and the first coating are on the same plane, and the first support member includes a plurality of support rods. Among the plurality of support rods, two adjacent support rods are connected at one end away from the connecting section to form the free end, and the enclosed area between the two adjacent support rods is larger than the area of ​​the first coating located between the two adjacent support rods.

5. The stent graft according to claim 4, characterized in that: In the length extension direction of the folded segment, the length dimension of the first support member is greater than the length dimension of the first covering film, and the free end of the first support member is exposed.

6. The stent graft according to claim 5, characterized in that: The support rods include long support rods and short support rods, two adjacent short support rods are connected to form a low wave peak, and two adjacent long support rods are connected to form a high wave peak. The low wave peaks and the high wave peaks are arranged alternately, and the low wave peaks are closer to the connecting section than the high wave peaks. The short support rods are completely covered by the first film, and the long support rods are partially exposed.

7. The stent graft according to any one of claims 1 to 3, characterized in that: The first support member and the first covering film are not completely in the same plane. On the first covering film near the free end, at least a portion of the first covering film is convex outward or concave inward relative to the plane where the first support member is located.

8. The stent graft according to claim 7, wherein: The first coating is formed by expanding the original coating between two adjacent support rods, and the surface area of ​​the first coating is larger than that of the original coating.

9. The stent graft according to claim 1, wherein: In a natural state, the projection of the free end of the folded section on the outer surface of the main body coincides with the connection point between the connecting section and the outer surface of the main body, or the projection of the free end of the folded section on the outer surface of the main body is closer to the proximal end of the main body than the connection point between the connecting section and the outer surface of the main body.

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