Covered stent and method of making same, covered stent system

Abstract

The application relates to a covered stent, a preparation method thereof and a covered stent system. The covered stent comprises a metal stent and a covering film arranged on the metal stent. At least the distal end of the covering film is provided with a hole region, the hole region is provided with a plurality of through holes, the through holes can enable blood to flow from the inside of the covered stent to the outside, and the through holes comprise at least one of a circular hole, a rhombic hole and a special-shaped hole. The metal stent comprises a plurality of annular stent segments arranged at intervals along an axial direction, each stent segment has a plurality of edges and a plurality of vertices. At least part of the stent segments is sequentially divided into small wave segments and large wave segments in the direction from the proximal end to the distal end, the small wave segments are used for sealing the covered stent, the large wave segments are used for supporting a blood vessel, and the number of vertices of each stent segment of the small wave segments is greater than the number of vertices of each stent segment of the large wave segments.

Description

[0001] This application is a divisional application of application number 202111424608.3 filed on November 26, 2021, entitled "Covered Scaffold and Covered Scaffold System". Technical Field

[0002] This invention relates to the field of medical device technology, and in particular to a covered stent, its preparation method, and a covered stent system. Background Technology

[0003] Descending aortic dissection aneurysm is a vascular disease generally caused by hypertension, hereditary connective tissue disorders, certain congenital cardiovascular diseases (such as descending aortic coarctation, descending aortic bicuspid aneurysm), pregnancy, severe trauma, heavy physical labor, and certain medications. Treatment methods generally include drug therapy, open surgery, and interventional surgery. Currently, the preferred treatment for Stanford type B (equivalent to DeBakey type III) is percutaneous endovascular stent grafting, with surgical intervention performed when necessary.

[0004] The therapeutic principle of covered stents is to replace or repair a portion of the blood vessels, such as arteries, to prevent or assist in preventing the rupture of aortic dissection aneurysms. A covered stent is composed of a tubular covered material and multiple stent segments. However, when the covered stent needs to be placed in the descending aorta region extending to the distal intercostal arteries, there is a high risk of occluding the intercostal arteries distal to the descending aorta, leading to spinal cord ischemia (SCI). Spinal cord ischemia and paraplegia are widely recognized as a terrible complication after thoracic descending aortic surgery.

[0005] Currently, to address the aforementioned spinal cord ischemia, a bare-metal stent is typically formed by extending the metal stent from the distal end of the covered stent. This bare-metal stent is placed at the distal intercostal artery to provide support without affecting the blood flow to branch vessels. Existing bare-metal stents are either made of overlapping and braided metal or by binding multiple stent segments together with polymer sutures. Regardless of whether metal braiding or polymer suture binding is used, reliable sealing and stable vascular support cannot be achieved. They also generally suffer from poor structural fatigue resistance, easy breakage, insufficient segmental connection strength, and easy displacement and loosening. Furthermore, they cannot provide directional compensation for branch blood flow at the distal end of the covered stent through a regular perforated structure, relying solely on passive drainage by the bare stent. Overall, they cannot simultaneously meet the multiple clinical requirements of sealing and occlusion, vascular support, branch blood supply, and long-term structural stability. Summary of the Invention

[0006] Therefore, it is necessary to provide a covered scaffold, its preparation method, and a covered scaffold system to address the above problems.

[0007] A covered stent includes: a metal stent and a covering film applied to the metal stent, wherein at least the distal end of the covering film is provided with a perforated region, the perforated region is provided with a plurality of through holes, the through holes enabling blood to flow from the interior of the covered stent to the exterior, wherein the through holes include at least one of circular holes, rhomboid holes, and irregularly shaped holes;

[0008] The metal stent includes a plurality of annular stent segments spaced apart along the axial direction of the covered stent, each stent segment having a plurality of edges and a plurality of vertices; the stent segments are sequentially divided into small segments and large segments along the direction from the proximal end to the distal end of the covered stent, the small segments being used to seal the covered stent, the large segments being used to support blood vessels, and the number of vertices in the small segments being greater than the number of vertices in the large segments.

[0009] In one embodiment, the hole region includes a first region and a second region, the first region being adjacent to the second region, and the second region being close to or covering the apex of the metal bracket;

[0010] The area of ​​the through hole in the first region is greater than the area of ​​the through hole in the second region.

[0011] In one embodiment, the second region refers to a region with a radius of 5mm to 7mm centered at the vertex of the support segment of the metal bracket;

[0012] The circular hole whose center falls within the first region is the first circular hole. The diameter d1 of the first circular hole is 1mm to 6mm. The center distance d2 between two adjacent first circular holes is 4mm to 6mm. The centers of three adjacent first circular holes are arranged in an equilateral triangle.

[0013] Or / and, the rhomboid hole whose center falls within the first region is a first rhomboid hole, and the area of ​​the first rhomboid hole is 0.78 mm². 2 ~7mm 2 The side spacing d3 between two adjacent first rhomboid holes is 1mm to 3mm, and the first rhomboid holes are arranged in a matrix.

[0014] In one embodiment, the circular hole whose center falls within the second region is a second circular hole, the diameter of the second circular hole is reduced by 40% to 70% relative to the diameter d1 of the first circular hole, and the diameter of the second circular hole is greater than 1 mm;

[0015] Or / and, the rhomboid hole whose center falls within the second region is a second rhomboid hole, and the area of ​​the second rhomboid hole is reduced by 40% to 70% relative to the area of ​​the first rhomboid hole.

[0016] In one embodiment, the distance between any point on the side of the second circular hole and the corresponding vertex of the metal bracket is greater than or equal to 3 cm;

[0017] Or / and, the distance between any point on the side of the second rhomboid hole and the corresponding vertex of the metal bracket is greater than or equal to 3cm.

[0018] In one embodiment, the first region and the second region are formed between each pair of adjacent edges on each support segment of the metal support, and the first region and the second region are distributed sequentially along the direction close to the vertex between the corresponding pair of adjacent edges;

[0019] The area of ​​the irregularly shaped hole is 0.78 mm. 2 ~7mm 2 The side spacing d4 between two adjacent irregular holes is 1mm to 3mm.

[0020] In one embodiment, the distance between any point on the side of the irregular hole and the corresponding vertex of the metal bracket is greater than or equal to 3 cm; and / or,

[0021] The area of ​​the irregular hole gradually increases along the direction away from the vertex between the corresponding two adjacent edges.

[0022] In one embodiment, the coating support further includes a first developing element disposed on the coating and located at the farthest and / or nearest end of the aperture region; and / or,

[0023] The through-holes are formed on the coating by laser drilling; and / or

[0024] The wavelet band includes two support segments at the nearest end, which are arranged crosswise on the inner and outer sides of the covering film; or, the two support segments at the nearest end are arranged axially spaced apart, and the near end of the covering support is provided with a bare support.

[0025] A covered stent system, the covered stent system comprising: at least one main covered stent and the covered stent described in any of the above;

[0026] The main covered stent and the covered stent are arranged sequentially along the blood flow direction.

[0027] In one embodiment, the proximal end of the covered stent may or may not overlap with the distal end of the adjacent main covered stent.

[0028] A method for preparing a covered scaffold as described in any of the preceding claims, comprising:

[0029] A coating and a metal support are provided, wherein at least the distal end of the coating is provided with a perforated area;

[0030] Multiple through holes are formed in the porous area of ​​the coating;

[0031] The coating is applied to the metal support.

[0032] The aforementioned covered stent, its preparation method, and covered stent system all feature multiple blood flow channels at least distal to the covered portion. These channels allow blood to flow from the interior to the exterior of the covered stent, ensuring unimpeded flow of blood from the true lumen of the descending aorta to the distal intercostal arteries. This guarantees continuous blood flow to the distal intercostal arteries and long-term patency, addressing the issues of poor long-term fatigue performance and insufficient connection strength inherent in traditional bare-metal covered stents. Furthermore, placing the blood flow channels on the covered portion, rather than on the bare-metal stent segment, enhances the tensile strength of the covered stent, ensuring both flexibility and support performance. This allows the covered stent to effectively reshape the true lumen of the blood vessel.

[0033] Furthermore, by designing the stent segments of the covered stent into small and large bands, structural functional zoning can be achieved. Small bands, characterized by low edge height, allow for a greater number of stent segments per unit length. Simultaneously, their multiple vertices and edges enable greater metal coverage within a unit area, resulting in better isolation. Therefore, small bands are suitable for sealing the proximal and distal ends of the covered stent. Large bands, on the other hand, offer strong structural support, stably supporting the vessel wall and maintaining the true lumen morphology. Through differentiated designs in terms of the number of vertices, edges, and edge height, the dual clinical needs of sealing and vascular support are perfectly met while ensuring stent flexibility. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a descending aortic dissection aneurysm provided in an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the installation of a covered stent provided by existing technology in a descending aortic dissection aneurysm;

[0036] Figure 3 This is a partial structural schematic diagram of a membrane-covered stent provided in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure of a film-coated support provided in an embodiment of the present invention;

[0038] Figure 5 for Figure 4 A schematic diagram showing the installation of the provided covered stent within a descending aortic dissection aneurysm;

[0039] Figure 6 This is a schematic diagram of the structure of a film-coated support provided in another embodiment of the present invention;

[0040] Figure 7 for Figure 6 A schematic diagram of the installation of a covered stent within a descending aortic dissection aneurysm;

[0041] Figure 8 for Figure 6 Another schematic diagram of the provided covered stent installation in a descending aortic dissection aneurysm;

[0042] Figure 9 , Figure 10 This is a partial structural schematic diagram of a membrane-covered stent provided in an embodiment of the present invention;

[0043] Figure 11 A partial structural schematic diagram of a film-coated stent provided in another embodiment of the present invention;

[0044] Figure 12 This is a partial structural schematic diagram of a film-coated scaffold provided in another embodiment of the present invention.

[0045] The labels in the appendix are explained as follows:

[0046] 10. Covered stent; 100. Metal stent; 110. Stent segment; 111. Rib; 112. Vertex; 120. Bare stent segment; 200. Covered; 110a. Large band; 110b. Small band; 210. Pore region; 240. Through hole; 241. Circular hole; 242. Rhomboid hole; 243. Irregular hole; 250. First region; 260. Second region; 270. Third region; 300. First imaging element; 400. Second imaging element; 20. Main covered stent; A. Distal intercostal artery; B. Descending aorta; B1. True lumen; B2. False lumen; B3. Tear; 30. Conventional covered stent. Detailed Implementation

[0047] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0052] 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," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0053] Aortic dissection aneurysm occurs when blood from within the descending aortic lumen enters the media of the descending aorta through a tear in the intima of the descending aorta B, causing media separation and extending along the long axis of the descending aorta B, resulting in a separation of the true and false lumens of the descending aortic wall. The internal blood flow direction is shown in the attached diagram. Figure 1 As indicated by the arrow in the diagram. To prevent rupture of descending aortic dissection aneurysms, a conventional covered stent is usually placed in the true lumen B1 of the descending aorta B. However, when it is necessary to place a covered stent in the descending aorta B extending to more distal intercostal arteries A (e.g., the 8th to 11th intercostal arteries), see [reference needed]. Figure 2 The intercostal artery A was blocked by a conventional covered stent 30, preventing sufficient blood flow and leading to spinal cord ischemia. Currently, to address spinal cord ischemia, the metal stent of the conventional covered stent 30 is typically extended distally to form a bare-metal stent. This bare-metal stent is placed at the distal intercostal artery A to provide support without affecting blood flow to branch vessels (i.e., the distal intercostal artery A). Existing bare-metal stents are either woven from overlapping metal segments or consist of multiple stent segments bound together with polymer filaments. The former type of bare-metal stent has poor long-term fatigue performance and is prone to breakage, leading to stent failure and damage to the blood vessel. The latter type of bare-metal stent cannot guarantee the connection strength between stent segments, making it easy for the polymer filaments to break due to external forces. Furthermore, the polymer filaments require strong fixation to hold the stent segments in place and prevent stent displacement. It should be noted that... Figure 2 The arrows in the diagram represent the direction of blood flow.

[0054] In response, one embodiment of the present invention provides a covered scaffold, such as... Figure 3 As shown, the film-coated support 10 includes a metal support 100 and a film 200 covering the metal support 100. See also... Figure 3 and Figure 4 At least the distal end of the covering 200 is provided with a perforated region 210, and the perforated region 210 is provided with a plurality of through holes 240, which allow blood to flow from the interior of the covered stent 10 to the exterior. The through holes 240 include... Figures 3 to 10 The circular hole 241 shown is Figure 11 The diamond-shaped hole 242 shown is Figure 12At least one of the irregular holes 243 shown.

[0055] Among them, the rhomboid hole 242 can be a parallelogram, a rectangle, or... Figure 12 The square hole shown is an example. It should also be noted that irregularly shaped holes 243 refer to holes with irregular shapes, such as arrow-shaped or trumpet-shaped holes. Considering the ease of processing, the through holes 240 can be processed before the coating 200 is applied to the metal support 100. During processing, laser drilling can be used to drill holes in the coating 200.

[0056] The aforementioned covered stent 10 can be applied to the treatment of descending aortic dissection aneurysms. The metal stent 100 is made of biocompatible metal materials such as nickel-titanium alloy, cobalt-nickel alloy, or stainless steel. (See attached image) Figure 5 and appendix Figure 7 As shown, the metal stent 100 may include a plurality of annular stent segments 110 spaced apart along the axial direction of the covered stent 10, each stent segment 110 having a plurality of ridges 111 and a plurality of vertices 112. The stent segments 110 are sequentially divided into small wavebands 110b and large wavebands 110a along the direction from the proximal end to the distal end of the covered stent. The small wavebands 110b are mainly used to seal the covered stent 10, and each stent segment 110 of the small wavebands 110b can be a structure of equal height or variable height, and the number of vertices 112 can be 10 to 16. The large wavebands 110a are mainly used to support blood vessels, and the number of vertices 112 of each stent segment 110 of the large wavebands 110a can be 5 to 8.

[0057] In one embodiment, such as Figure 4 As shown, the small band 110b may include two support segments 110, that is, there may be two support segments 110 at the proximal end. These two support segments 110 are arranged axially spaced apart, and the crests and troughs of the multiple support segments 110 are opposite to each other. Among them, the proximal end of the covered stent 10 may be provided with a bare stent segment 120. It should be noted that the stent segment 110 may be made of metal wire bent into a wavy structure, where the crest refers to the highest point of the metal wire in the wave, and the trough refers to the lowest point of the metal wire in the wave.

[0058] In another embodiment, such as Figure 6 As shown, wavelet 110b may include two support segments 110, which are axially aligned with the support 10 and are intersectingly arranged on the inner and outer sides of the covering film 200 (see...). Figure 7 This means that the troughs and crests of the two support segments 110 are opposite each other. This arrangement improves the sealing effect of the covered stent 10. Notably, the proximal end of the covered stent 10 does not require a bare stent segment 120.

[0059] The aforementioned coating 200 can be made of polymer materials such as PET (Polyethylene terephthalate), PTFE (Polytetrafluoroethylene), and ePTFE (Expanded Polytetrafluoroethylene). The coating 200 can be fixed to the metal bracket 100 by means of sewing or other methods. The sewing thread can be made of polymer materials such as PET, PTFE, ePTFE, or PP (Polypropylene).

[0060] The aforementioned pore region 210 may be distributed only at the distal end of the coating 200 (see...). Figure 4 It can also be distributed at the distal and middle parts of the film covering 200 (see...). Figure 6 These can also be distributed at the distal, middle, and proximal ends of the endovascular stent 200, mainly due to the function of the endovascular stent 10. It should be noted that the distal end of the endovascular stent 200 refers to the end of the endovascular stent 200 furthest from the heart, the proximal end refers to the end closest to the heart, and the middle part refers to the portion of the endovascular stent 200 located between the proximal and distal ends. (See attached...) Figure 5 As shown, when the covered stent 10 is used to repair the dissection tear B3 in the descending aorta region B, the perforation region 210 can be distributed only at the distal end of the covered stent 200 to ensure unobstructed blood flow in the intercostal artery A. The proximal and middle parts of the covered stent 200 are used to block the true lumen B1 and false lumen B2 of the descending aorta B (see...). Figure 4 This prevents blood from flowing into the false lumen B2 of the descending aorta. In this case, such as Figure 4 As shown, the proximal end of the covered stent 10 may be provided with a bare stent segment 120 for anchoring the covered stent 10 in the anchoring region of the blood vessel. This bare stent segment 120 may have 4 to 8 vertices 112, ensuring both radial support force and anchoring capability of the covered stent 10, preventing displacement. (See attached diagram) Figure 7 and appendix Figure 8 As shown, when the covered stent 10 primarily extends the main covered stent 20 (equivalent to the conventional covered stent 30), the perforated region 210 can be distributed in the middle and distal parts of the covered stent 10, or in the proximal, middle, and distal parts of the covered stent 10. In this case, the covered stent 10 provided in this embodiment is used to ensure unobstructed blood flow in branch vessels while remodeling diseased vessels, and can overlap with the main covered stent 20 (see...). Figure 7 ) can also be non-overlapping (see Figure 8 ).

[0061] The aforementioned covered stent 10, at least at the distal end of the covering 200, has a perforated region 210. The through-holes 240 in this perforated region 210 allow blood flow from the interior to the exterior of the covered stent 10. Blood in the true lumen B1 of the descending aorta B can flow smoothly through the perforated region 210 of the covering 200 to the distal intercostal artery A, ensuring constant blood flow to the distal intercostal artery A and guaranteeing long-term patency. This solves the problems of poor long-term fatigue performance and insufficient connection strength of traditional bare-metal covered stents 30. The through-holes 240 in the perforated region 210 are located on the covering 200. The tensile strength of the covered stent 10 can be enhanced on the non-bare metal stent segment, ensuring both the flexibility and support performance of the covered stent 10, so that the covered stent's support for the blood vessel can achieve the purpose of reshaping the true lumen. In addition, the through hole 240 can be set with at least one of the following: circular hole 241, rhomboid hole 242, and irregular hole 243. During application, the shape of the through hole 240 with the best structure can be selected according to the specific situation, which not only ensures that blood flow can flow smoothly from the inside of the covered stent 10 to the outside, but also reduces the difficulty of the covered stent preparation.

[0062] In some embodiments of the present invention, as shown in the appendix Figure 4 and appendix Figure 6 As shown, the covered stent 10 also includes a first imaging element 300, which is disposed on the covering 200 and located at the distal and / or proximal ends of the perforation region 210. The first imaging element 300 is used to display the starting or ending position of the perforation region 210 of the covered stent 10, facilitating the alignment of the perforation region 210 with the distal intercostal artery A, thereby ensuring unobstructed blood flow with the distal intercostal artery A. Optionally, the first imaging element 300 is made of at least one of tantalum, platinum-iridium alloy, and gold. The first imaging element 300 can be fixed by suture. In addition, at least one first imaging element 300 is disposed at the proximal end of the perforation region 210, for example, two are evenly disposed circumferentially.

[0063] Similarly, as Figure 4 and Figure 6 As shown, a second developing element 400 is provided at the proximal edge and / or distal edge of the coating 200. This second developing element 400 allows for precise positioning of the coating support 10. The material, shape, and connection method of the second developing element 400 can be the same as those of the first developing element 300. At least one second developing element 400 is provided at each of the proximal and distal edges of the coating 200, for example, four are evenly distributed circumferentially.

[0064] In some embodiments of the present invention, such as Figure 9 , Figure 11 and Figure 12As shown, the perforation region 210 includes a first region 250 and a second region 260. The first region 250 is adjacent to the second region 260, and the second region 260 is close to or covers the apex 112 of the metal stent 100. The area of ​​the through-hole 210 in the first region 250 is larger than the area of ​​the through-hole 210 in the second region 260. This setting of the through-hole area in each region of the perforation region 210 ensures the connection strength between the covering 200 and the apex 112 of the metal stent 100, and also prevents the through-holes close to the apex 112 of the metal stent 100 from being exposed and touching the blood vessel wall due to excessively large areas. On the other hand, it also ensures that the through-holes far from the apex 112 of the metal stent 10 have sufficient area, so that blood can flow smoothly from the inside of the covered stent 10 to the outside of the covered stent 10.

[0065] The parameters of the through holes 240 in the first region 250 and the second region 260 are described below:

[0066] (1) Regarding the case where the through hole 240 is a circular hole 241: In some embodiments of the present invention, such as Figure 9 and Figure 10 As shown, the second region 260 refers to the region in the hole region 210 with a radius of 5mm to 7mm (e.g., 5mm, 6mm, 7mm, etc.) centered on the vertex 112 of the corresponding metal bracket segment 110 of the metal bracket 100. It can be understood that the hole region 210 of the coating 200 has multiple second regions 260, the number of which is related to the number of vertices 112 of the metal bracket 100 covered by the hole region 210. Therefore, the region in the hole region 210 other than the second region 260 can be regarded as the first region 250, and the size of the first region 250 can be set according to specific circumstances.

[0067] The circular hole 241 whose center falls within the first region 250 is the first circular hole 2411. The diameter d1 of the first circular hole 2411 is 1mm~6mm (e.g., 1mm, 2mm, 1mm, 3mm, 4mm, 5mm, 6mm, etc.). The center distance d2 between two adjacent first circular holes 2411 is 4mm~6mm (e.g., 4mm, 4.5mm, 5mm, 5.5mm, 4mm, 6mm, etc.). The centers of three adjacent first circular holes 2411 are arranged in an equilateral triangle (see...). Figure 10 ).

[0068] The above parameters are set to ensure that the size of the first circular hole 2411 is larger than the size of the distal intercostal artery A (e.g., between the 8th and 11th intercostal spaces), and that the edges of the first circular holes 2411 between each pair are smaller than the size of the distal intercostal artery A (e.g., between the 8th and 11th intercostal spaces). This ensures that the intercostal artery A can randomly fall at the perforated segment of the covering 200, thus maintaining unobstructed blood flow within the intercostal artery A. These parameters can be set according to specific circumstances. For example, the diameter d1 of the first circular hole 2411 is 2 mm, and the center-to-center distance d2 between two adjacent first circular holes 2411 is 4 mm.

[0069] Furthermore, in some embodiments of the present invention, such as Figure 9 As shown, the circular hole 241 whose center falls within the second region 260 is the second circular hole 2412. The diameter of the second circular hole 2412 is reduced by 40% to 70% (e.g., 40%, 50%, 60%, 70%) compared to the diameter d1 of the first circular hole 2411, and the diameter of the second circular hole 2412 is equal to or greater than 1 mm, specifically 1 mm to 2 mm (e.g., 1 mm, 1.2 mm, 1.5 mm, 2 mm, etc.). The above parameter settings ensure that the apex 112 of the metal stent 100 will not protrude from the second circular hole 2412, preventing the apex 112 of the metal stent 100 from touching the blood vessel wall and causing a secondary rupture in the blood vessel wall.

[0070] Furthermore, in some embodiments of the present invention, the distance between any point on the side of the second circular hole 2412 and the vertex 112 of the corresponding support segment 110 of the metal bracket 100 in the second region 260 is greater than or equal to 3 cm (e.g., 3 cm, 3.2 cm, 3.5 cm, etc.). That is, in the second region 260, no circular hole 241 is provided in the third region 270 with a radius of 3 mm centered on the vertex 112 of the support segment 110 of the metal bracket 100. In this way, it can be ensured that the vertex 112 of the metal bracket 100 can be firmly fixed on the film 200.

[0071] It should be noted that when the diameter d1 of the first circular hole 2411 is 6mm and the diameter of the second circular hole 2412 is reduced by 40% relative to the diameter d1 of the first circular hole 2411, the diameter of the second circular hole 2412 can be 3.6mm. In addition, the distance between the second circular hole 2412 and the vertex 112 of the support segment 110 of the corresponding metal support 100 in the second region 260 is greater than or equal to 3cm. Therefore, if the diameter of the second circular hole 2412 is too large, it will cover the vertex 112 of the metal support 100.

[0072] (2) Regarding the case where the through hole 240 is a rhomboid hole 242: In some embodiments of the present invention, such as Figure 11As shown, the coating 200 includes a first region 250 and a second region 260. The arrangement range of the first region 250 and the second region 260 is the same as when the through hole 240 is a circular hole 241. The rhomboid hole 242 centered within the first region 250 is the first rhomboid hole 2421, and the area of ​​the first rhomboid hole 2421 is 0.78 mm². 2~ 7mm 2 (e.g., 0.78mm) 2 1mm 2 3mm 2 5mm 2 7mm 2 The side spacing d3 of two adjacent first rhomboid holes 2421 is 1mm to 3mm (e.g., 1cm, 2cm, 3cm, etc.), so that the diameter of the intercostal artery is greater than the side spacing of the adjacent first rhomboid holes 2421, allowing the intercostal artery to be unobstructed for a distance of 1-3mm; the first rhomboid holes 2421 are arranged in a matrix. It should be noted that the side spacing d3 of the first rhomboid holes 2421 refers to the shortest distance between the sides of two adjacent first rhomboid holes 2421; in addition, the center line connecting two adjacent first rhomboid holes 2421 in the axial direction of the covered stent 10 is parallel to the axis of the covered stent 10, and the two first rhomboid holes 2421 are aligned in the circumferential direction of the covered stent 10 so that the first rhomboid holes 2421 are arranged in a matrix. The above parameters are set to ensure that the area of ​​the first rhomboid hole 2421 is larger than or equal to the cross-sectional area of ​​the distal intercostal artery A (e.g., between the 8th and 11th intercostal spaces), and the distance between the edges of two adjacent first rhomboid holes 2421 is smaller than the size of the distal intercostal artery A (e.g., between the 8th and 11th intercostal spaces). This also allows the intercostal artery A to randomly fall on the perforated section of the covering 200, thus ensuring unobstructed blood flow within the intercostal artery A. The size of the first region 250 can be set according to specific circumstances. Taking the first rhomboid hole 2421 only located at the distal end of the covering 200 as an example, the first region 250 can refer to the entire distal end of the covering 200, or it can refer to the region of the distal end of the covering 200 near the intercostal artery A.

[0073] Furthermore, in some embodiments of the present invention, such as Figure 11 As shown, the rhomboid hole 242 centered within the second region 260 is the second rhomboid hole 2422. The area of ​​the second rhomboid hole 2422 is reduced by 40% to 70% (e.g., 40%, 50%, 60%, 70%) compared to the area of ​​the first rhomboid hole 2421. The above parameter settings ensure that the apex 112 of the metal stent 100 will not protrude from the second rhomboid hole 2422, preventing the apex 112 of the metal stent 100 from touching the blood vessel wall and causing a secondary rupture in the blood vessel wall.

[0074] Furthermore, in some embodiments of the present invention, the distance between any point on the side of the second rhomboid hole 2422 and the vertex 112 of the corresponding support segment 110 of the metal bracket 100 is greater than or equal to 3cm (e.g., 3cm, 3.2cm, 3.5cm, etc.), that is, no rhomboid hole 242 is provided within the third region 270 with the vertex 112 of the support segment 110 of the corresponding metal bracket 100 as the center and a radius of 3mm. In this way, it can be ensured that the vertex 112 of the metal bracket 100 can be firmly fixed on the film 200.

[0075] (3) In the case where the through hole 240 is an irregular hole 243, the coating 200 includes a first region 250 and a second region 260. The setting range of the first region 250 and the second region 260 is the same as that in the case where the through hole 240 is a circular hole 241.

[0076] like Figure 12 As shown, in some embodiments of the present invention, a first region 250 and a second region 260 are formed between each pair of adjacent edges 111 on each support segment 110 of the metal bracket 100, and the first region 250 and the second region 260 are distributed sequentially along the direction close to the vertex 112 between the corresponding pair of adjacent edges 111; the irregular hole 243 is set away from the support segment 110 of the metal bracket 100, and the area of ​​the irregular hole 243 is 0.78 mm². 2 ~7mm 2 (e.g., 0.78mm) 2 1mm 2 3mm 2 5mm 2 7mm 2 The side spacing d4 between two adjacent irregular holes 243 is 1mm to 3mm (e.g., 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc.). It should be noted that the side spacing d4 of the irregular holes 243 refers to the shortest distance between the sides of two adjacent irregular holes 243. The above parameter settings ensure both the strength of the covering membrane 200 and that the diameter of the intercostal artery A is greater than the edge distance of the irregular holes 243, thus ensuring the patency of the intercostal artery A.

[0077] Furthermore, in some embodiments of the present invention, such as Figure 12 As shown, the area of ​​the irregular hole 243 gradually increases along the direction away from the vertex 112 between the two adjacent edges 111. In this way, the membrane 200 located near the vertex 112 of the metal support 100 can be kept strong while ensuring smooth blood flow.

[0078] like Figure 12As shown, furthermore, the distance between any point on the edge of the irregular hole 243 and the vertex 112 of the corresponding support segment 110 of the metal bracket 100 is greater than or equal to 3cm (e.g., 3cm, 3.2cm, 3.5cm, etc.). That is, no irregular hole 243 is provided within the third region 270 with the vertex 112 of the support segment 110 of the corresponding metal bracket 100 as the center and a radius of 3mm. In this way, it can be ensured that the vertex 112 of the metal bracket 100 can be firmly fixed on the coating 200.

[0079] In some embodiments of the present invention, the through-holes 240 are formed on the coating 200 by laser drilling. This method of forming the hole regions 210 is simple and facilitates the fabrication of the coating support. During production, multiple hole regions 210 can be formed on the distal end of the coating 200 before the coating 200 is applied to the metal support 100, thus reducing the difficulty of drilling holes in the coating 200.

[0080] Another embodiment of the present invention also provides a covered scaffold system, such as Figure 7 and Figure 8 As shown, the covered stent system includes: at least one main covered stent 20 and the covered stent 10 described in any of the above-mentioned embodiments; the main covered stent 20 and the covered stent 10 are arranged sequentially along the blood flow direction.

[0081] The structure and material of the primary graft 20 can be the same as those of the conventional graft 30, and therefore will not be described here. The number of primary grafts 20 can be set according to specific circumstances; for example, such as... Figure 7 and Figure 8 As shown, there is one main endothelial stent 20.

[0082] In the aforementioned covered stent system, the distal end of at least the covering 200 of the covered stent 10 is provided with multiple perforated regions 210. These perforated regions 210 allow blood to flow from the interior to the exterior of the covered stent. Blood in the true lumen B1 of the descending aorta can flow unimpeded through the perforated regions 210 of the covering 200 to the distal intercostal artery A, ensuring continuous blood flow to the distal intercostal artery A and guaranteeing long-term patency. This solves the problems of poor long-term fatigue performance and insufficient connection strength of existing bare-metal covered stents 100. Furthermore, placing the perforated regions 210 on the covering 200, rather than on the bare-metal stent segment, enhances the tensile strength of the covered stent, ensuring both flexibility and support performance, thus enabling the covered stent to reshape the true lumen B1.

[0083] In some embodiments of the present invention, the proximal end of the covered stent 10 overlaps with the distal end of the adjacent main covered stent 20 (see [link]). Figure 7 ) or not overlapping (see Figure 8 When applying this feature, you can configure it according to the specific circumstances.

[0084] 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.

[0085] 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, characterized in that, include: A metal stent (100) and a membrane (200) covering the metal stent (100), wherein at least the distal end of the membrane (200) is provided with a perforated region (210), the perforated region (210) is provided with a plurality of through holes (240), the through holes (240) enabling blood to flow from the interior of the membrane stent (10) to the exterior, wherein the through holes (240) include at least one of a circular hole (241), a diamond-shaped hole (242), and an irregularly shaped hole (243); The metal stent (100) includes a plurality of annular stent segments (110) spaced apart along the axial direction of the covered stent (10), each stent segment (110) having a plurality of edges (111) and a plurality of vertices (112); at least a portion of the stent segments (110) are sequentially divided into small wavebands (110b) and large wavebands (110a) along the direction from the proximal end to the distal end of the covered stent (10), the small wavebands (110b) being used to seal the covered stent (10), the large wavebands (110a) being used to support blood vessels, and the number of vertices of each stent segment (110) in the small wavebands (110b) being greater than the number of vertices of each stent segment (110) in the large wavebands (110a).

2. The covered stent according to claim 1, characterized in that, The hole region (210) includes a first region (250) and a second region (260), the first region (250) being adjacent to the second region (260), and the second region (260) being close to or covering the apex (112) of the metal bracket (100). The area of ​​the through hole (210) in the first region (250) is greater than the area of ​​the through hole (210) in the second region (260).

3. The covered stent according to claim 2, characterized in that, The second region (260) refers to the region with a radius of 5mm to 7mm centered on the vertex (112) of the support segment (110) of the metal support (100); The circular hole (241) whose center falls within the first region (250) is the first circular hole (2411). The diameter d1 of the first circular hole (2411) is 1mm~6mm, the center distance d2 between two adjacent first circular holes (2411) is 4mm~6mm, and the centers of three adjacent first circular holes (2411) are arranged in an equilateral triangle. Or / and, the rhomboid hole (242) whose center falls within the first region (250) is a first rhomboid hole (2421), and the area of ​​the first rhomboid hole (2421) is 0.78 mm. 2 ~7mm 2 The side spacing d3 of two adjacent first rhomboid holes (2421) is 1mm~3mm, and the first rhomboid holes (2421) are arranged in a matrix.

4. The covered stent according to claim 3, characterized in that, The circular hole (241) whose center falls within the second region (260) is the second circular hole (2412). The diameter of the second circular hole (2412) is reduced by 40% to 70% relative to the diameter d1 of the first circular hole (2411), and the diameter of the second circular hole (2412) is equal to or greater than 1 mm. Or / and, the rhomboid hole (242) whose center falls within the second region (260) is a second rhomboid hole (2422), the area of ​​the second rhomboid hole (2422) being 40% to 70% smaller than the area of ​​the first rhomboid hole (2421).

5. The covered stent according to claim 4, characterized in that, The distance between any point on the side of the second circular hole (2412) and the corresponding vertex (112) of the metal bracket (100) is greater than or equal to 3cm; Or / and, the distance between any point on the side of the second rhomboid hole (2422) and the corresponding vertex (112) of the metal bracket (100) is greater than or equal to 3cm.

6. The covered stent according to claim 2, characterized in that, In the metal bracket (100), the first region (250) and the second region (260) are formed between each pair of adjacent edges (111) on each bracket segment (110), and the first region (250) and the second region (260) are distributed sequentially along the direction close to the vertex (112) between the corresponding pair of adjacent edges (111); The area of ​​the irregular hole (243) is 0.78 mm. 2 ~7mm 2 The side spacing d4 between two adjacent irregular holes (243) is 1mm~3mm.

7. The covered stent according to claim 6, characterized in that, The distance between any point on the side of the irregular hole (243) and the corresponding vertex (112) of the metal bracket (100) is greater than or equal to 3 cm; and / or, The area of ​​the irregular hole (243) gradually increases along the direction away from the vertex (112) of the corresponding adjacent two edges (111).

8. The covered stent according to any one of claims 1-7, characterized in that, The coating support (10) further includes a first developing element (300), which is disposed on the coating (200) and located at the farthest and / or nearest end of the perforation region (210); and / or, The through-hole (240) is formed on the coating (200) by laser drilling; and / or, The wavelet (110b) includes two support segments (110) at the nearest end, which are arranged crosswise on the inner and outer sides of the covering (200); or, the two support segments (110) at the nearest end are arranged axially spaced apart, and the near end of the covering support (10) is provided with a bare support (120).

9. A covered scaffold system, characterized in that, The covered stent system includes: at least one main covered stent (20) and the covered stent (10) according to any one of claims 1-8. The main covered stent (20) and the covered stent (10) are arranged sequentially along the blood flow direction.

10. The covered stent system according to claim 9, characterized in that, The proximal end of the covered stent (10) may or may not overlap with the distal end of the adjacent main covered stent (20).

11. A method for preparing a covered scaffold as described in any one of claims 1-8, characterized in that, include: A film (200) and a metal support (100) are provided, wherein at least the distal end of the film (200) is provided with a hole region (210). Multiple through holes (240) are formed in the hole region (210) of the coating (200). The film (200) is applied to the metal support (100).

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