A covered stent

Abstract

This application discloses a covered stent comprising multiple first annular structures and multiple second annular structures distributed axially. The surface of each first annular structure is covered and connected to form a covered segment, exhibiting good flexibility and adaptability to complex vascular anatomy. The axial ends of the second annular structures are provided with winding rings, and adjacent second annular structures are interlocked via these winding rings to form a distal stent segment. This structure effectively resists axial shortening and provides stable distal anchoring. The first annular structure at the end of the covered segment and the second annular structure at the beginning of the distal stent segment are also interlocked via winding rings, achieving a reliable connection between the two segments. A third annular structure may also be provided in the distal stent segment to enhance connection stability. Through a zoned design, this application ensures overall stent flexibility and adherence to the vessel wall while extending the distal anchoring area and maintaining unobstructed branch blood flow, significantly improving the clinical efficacy of endovascular repair of branch vessels.

Description

Technical Field

[0001] This application relates to the field of medical device technology, specifically to a covered stent. Background Technology

[0002] With the development of technology, endovascular interventional surgery has become the main treatment for aortic vascular diseases. Compared with open surgery, endovascular intervention, by releasing stents to the lesion site, repairs and reconstructs diseased blood vessels, offering advantages such as minimal trauma and rapid recovery. Clinically, aortic vascular lesions may affect branch vessels, requiring reconstruction of these branches to restore their patency, thereby completing the treatment of the aortic disease.

[0003] When aortic lesions involve branch vessels, such as branches of the aorta, visceral branches of the abdominal aorta, and distal iliac artery branches, endovascular interventional treatment requires consideration of reconstructing the branch vessels to ensure blood flow. This can be achieved using covered stents.

[0004] Existing covered stents are mainly divided into two types based on their working mechanism: self-expanding covered stents and balloon-expandable covered stents. Self-expanding covered stents typically use highly elastic metallic materials as stent rings, which are connected by a covering material to form a complete structure. During deployment, they expand automatically without the need for a balloon. Usually, the stent is loaded into a designated delivery system before implantation. After being delivered to the designated lesion site via interventional procedures, the delivery sheath is removed, and the stent is released, completing the reconstruction of vascular access. Balloon-expandable covered stents typically have stent rings made of plastic materials such as cobalt-chromium alloy or stainless steel, with a covering to form a complete covered stent. During use, the stent is pre-loaded onto a balloon catheter and delivered to the designated lesion site via interventional procedures. Then, balloon inflation is applied to expand the stent to the designed diameter, releasing it into the blood vessel.

[0005] Aortic branches are typically located on one or both sides of the main aortic trunk, and their anatomical morphology varies greatly from person to person. Some patients have complex branch morphologies, so the branch-covered stent needs to have good flexibility to adapt to the complex anatomical structure of the branch vessels during reconstruction. The distal ends of the branch vessels may also have secondary branches, and the covered stent needs to be structurally designed at the locations of these secondary branches to ensure their blood supply. Endovascular repair usually involves reconstructing the branch artery through methods such as fenestration. The branch-covered stent will be bridged to one side of the fenestration site of the main covered stent. Additionally, other organs around the vessel may exert a compressive effect on the branch-covered stent. To prevent endoleak and ensure long-term patency of the reconstructed branch vessels, the branch-covered stent needs to have good radial support and compression resistance to meet clinical needs.

[0006] Existing technologies for branch vessel reconstruction all have certain limitations in clinical application. The flexibility and radial support of self-expanding covered stents depend on the combination of stent structural design and covering process. In the aforementioned clinical application scenarios of branch reconstruction, existing solutions cannot simultaneously achieve ideal requirements for both flexibility and radial support. Furthermore, due to the secondary branches, distal anchoring is often insufficient, resulting in inadequate stability. Balloon-expandable stents utilize radial inflation with a balloon to induce permanent plastic deformation of the stent material to achieve the specified diameter. Therefore, the expanded stent is relatively rigid but lacks bending flexibility. Additionally, due to the inherent elastic properties of the stent material, radial recoil may occur after the stent has expanded to the specified diameter.

[0007] Therefore, in view of the shortcomings of existing stents in clinical applications, it is necessary to address the above-mentioned technical deficiencies, especially in the case of reconstructing aortic branch vessels, where existing products are not well adapted to the complex anatomy of branch vessels, ensuring long-term patency and the blood supply needs of secondary branches, so as to meet clinical use and improve treatment outcomes. Summary of the Invention

[0008] This application provides a covered stent that can solve the technical problems existing in the prior art, such as poor flexibility of covered stents when reconstructing aortic branch vessels, difficulty in effectively adapting to the complex anatomical structure of branch vessels, and inaccurate distal anchoring due to unstable distal axial connection and easy shortening, which affects the treatment effect.

[0009] In a first aspect, embodiments of this application provide a covered stent, which includes: Multiple first annular structures are distributed along the axial direction and are connected to form covered segments by being covered with a membrane; Multiple second annular structures are distributed along the axial direction; at least one end of the second annular structure has several winding rings; any two adjacent second annular structures are nested together by the winding rings to form a distal support segment. The first annular structure at the end of the film-coated section is connected to the second annular structure at the beginning of the distal support section by a winding ring.

[0010] Preferably, when the second annular structure is unfolded in plane, it is a wavy wire with crests and troughs, and the crests and / or troughs of the wavy wire cross and wrap around to form the winding loop; A portion of the first annular structure at the end of the film-coated section is circumferentially inserted and sleeved in the winding ring of the second annular structure at the beginning of the distal support section.

[0011] Preferably, when the first annular structure is unfolded, it is a wavy wire with crests and troughs, and the spacing between the crests and troughs of the wavy wire is different. There is an angular difference between any two adjacent first ring structures in the circumferential direction.

[0012] Preferably, the winding ring includes an arc portion and two line segments, with the two line segments respectively connected to both ends of the arc portion; the two line segments are arranged intersectingly, and the intersection points fit together to form a fitting space with the arc portion.

[0013] Preferably, all the crests and troughs of the wavy wire are interlocked to form winding loops, and any two adjacent second ring structures are configured such that the winding loop at the crest of one second ring structure is nested with the winding loop at the trough of the other second ring structure.

[0014] Preferably, the wavy wire is cross-wound at some crests to form a winding loop, and the wavy wire is cross-wound at some troughs to form a winding loop. Any two adjacent second ring structures are configured such that the winding loop at the crest of one second ring structure is nested with the trough of the other second ring structure.

[0015] Preferably, the wavy wire is cross-wound at some of its crests to form winding loops, and there are several crests between adjacent winding loops. Any two adjacent second ring structures are configured such that the winding loop at the crest of one second ring structure is nested with the trough of the other second ring structure.

[0016] Preferably, the wavy wire is cross-wound at some of its troughs to form winding loops, and there are several troughs between adjacent winding loops. Any two adjacent second ring structures are configured such that the winding loop at the trough of one second ring structure is connected to the crest of the other second ring structure.

[0017] Preferably, a third ring structure is connected between any two adjacent second ring structures in the distal support segment; the third ring structure is a wavy wire with crests and troughs when unfolded in plane.

[0018] Preferably, all the crests and troughs of the second annular structure are cross-wound to form winding loops; or, some of the crests and troughs of the wavy wire are cross-wound to form winding loops. The third annular structure and the two second annular structures are configured such that the winding ring at the trough of one of the second annular structures is connected to the crest of the third annular structure, and the winding ring at the crest of the other second annular structure is connected to the trough of the third annular structure.

[0019] The beneficial effects of the technical solutions provided in this application include: Multiple independent first annular structures are arranged axially to form the covered segment. There is no rigid interconnection between the rings; they are only wrapped and connected by a highly elastic and biocompatible covering. This design essentially transforms the rigid coupling between rings in traditional laser-cut stents into flexible coupling through the covering material. When the vessel is tortuous, adjacent first annular structures can achieve local angular deflection through the limited extension and relative slippage of the covering, thus conforming to the tortuous shape of the vessel without significantly changing the axial length of the stent. This mechanism effectively relieves the tortuous constraints between rings, significantly improving the stent's compliant tracking ability in tortuous vessel segments (such as the aortic arch and iliac bifurcation), and reducing the risk of vessel wall stress concentration, intimal hyperplasia, or stent fracture caused by excessive stent stiffness.

[0020] Multiple second-ring structures are interconnected via winding rings at their ends to form the distal stent segment. The winding rings are essentially self-locking mechanical interconnecting units; the resulting interlocking space allows for slight axial movement between adjacent second-ring structures, but strictly limits their free separation or large relative displacement. This is equivalent to constructing a chain structure with axial preload at the distal end of the stent: each second-ring structure acts as both a load-bearing and constraint body, transmitting axial loads through the interlocking of the winding rings. This design structurally suppresses the tendency for progressive stent shortening after deployment and during long-term use due to blood flow impact, vascular pulsation, or external compression, ensuring stable anchorage of the distal stent in the lesion area (such as branch openings) and avoiding incomplete lesion coverage or endoleak caused by stent shortening.

[0021] The flexible covered segment adapts to the tortuosity and deformation of the proximal main vessel, while the rigidly interlocked distal stent segment provides stable support and anchorage within the branch vessels. The distal stent segment employs a bare-metal stent design without a cover, retaining the open structure of the metal mesh, allowing blood flow to smoothly perfuse through the stent sidewalls to secondary branches. This achieves both main vessel reconstruction and ensures blood flow perfusion to important branches, preventing branch ischemia complications. Overall, it achieves a balance between the seemingly contradictory proximal compliance with tortuosity and the distal resistance to shortening—two crucial properties for branch vessel reconstruction. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the covered stent of this application; Figure 2 This is a schematic diagram of the planar unfolding of the first annular structure of this application; Figure 3 This is a three-dimensional structural diagram of the first ring structure of this application; Figure 4 This is a schematic diagram showing the periodic arrangement of multiple first annular structures in this application; Figure 5This is a schematic diagram of the second annular structure of this application; Figure 6 This is a schematic diagram of the winding ring of the second annular structure of this application; Figure 7 This is a schematic diagram of the connection of Form 1 when the multiple second annular structures of this application are unfolded in a planar manner; Figure 8 This is a schematic diagram showing the connection of Case 1 of Form 5 when multiple second annular structures are unfolded in planar states according to this application; Figure 9 This is a connection diagram of Case 2 of Form 5 when the second annular structure of this application is in its planar unfolded state. Figure 10 This is a schematic diagram showing the connection of Form 2 when multiple second annular structures are unfolded in the planar state of this application; Figure 11 This is a schematic diagram of the connection of Form 3 when multiple second annular structures are unfolded in the planar state according to this application.

[0023] In the figure: 1. First ring structure; 2. Coating; 3. Coating section; 4. Second ring structure; 400. Winding ring; 4001. Arc section; 4002. Line section; 5. Distant support section; 6. Third ring structure. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0025] Firstly, to enable those skilled in the art to understand this application.

[0026] Existing technologies for branch vessel reconstruction all have certain limitations in clinical application. The flexibility and radial support of self-expanding covered stents depend on the combination of stent structural design and covering process. In the aforementioned clinical application scenarios of branch reconstruction, existing solutions cannot simultaneously achieve ideal requirements for both flexibility and radial support. Furthermore, due to the secondary branches, distal anchoring is often insufficient, resulting in inadequate stability. Balloon-expandable stents utilize radial inflation with a balloon to induce permanent plastic deformation of the stent material to achieve the specified diameter. Therefore, the expanded stent is relatively rigid but lacks bending flexibility. Additionally, due to the inherent elastic properties of the stent material, radial recoil may occur after the stent has expanded to the specified diameter.

[0027] This application proposes an innovative self-expanding covered stent technology solution, which features excellent flexibility, radial support, and compression resistance, effectively ensuring the availability of effective lumen for aortic branch vessel reconstruction and maintaining patency. Simultaneously, a bare stent segment without covering is provided distally, ensuring adequate anchoring while guaranteeing blood supply to secondary branches, providing stable connection, and minimizing the risk of shortening. This effectively ensures the stability of aortic branch vessel reconstruction and addresses the shortcomings of existing covered stents in clinical applications.

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0029] Example 1, Reference Figure 1 As shown, this application embodiment provides a covered stent, which includes: Multiple first annular structures 1 are distributed along the axial direction and are connected to form covered segments 3 by being covered with a membrane 2; Multiple second ring structures 4 are distributed along the axial direction; at least one of the two ends of the second ring structure 4 along the axial direction has a number of winding rings 400; any two adjacent second ring structures 4 are nested together by the winding rings 400 to form a distal support section 5; the distal support section 5 is not covered with a film. The first annular structure 1 at the end of the film-coated section 3 is connected to the second annular structure 4 at the beginning of the distal support section 5 via a winding ring 400.

[0030] In this embodiment, it is important to explain that existing technologies often employ parallel arrangement or helical winding methods. For example, patent document US6673102B1 provides a technical solution with a hybrid covered and uncovered segment, where the covered segment stent ring uses helical winding, and the uncovered segment uses a cross-weaving method, rather than using a cross-winding loop 400. Because the uncovered segment is integrally formed, the stent rings at the cross-connection points are not relatively firmly connected, resulting in the uncovered segment being shortened. Furthermore, the technical solution in patent document CN105662666B uses a cross-weaving method to form the stent ring as a whole before covering it with a film. While this solution has a good structural morphology, the bending performance of the stent cannot be guaranteed. Moreover, most related technologies use longitudinal parallel arrangement or cover the surface of a laser-engraved metal stent; therefore, the flexibility and distal anchoring stability of the uncovered segment may not meet the requirements for clinical applications.

[0031] In this application, the non-covered segment, i.e., the distal stent segment 5, has a winding ring 400 formed by cross-winding. The winding ring 400 adopts a figure-eight cross-winding to form a small ring structure, which can connect multiple second ring structures 4 of the non-covered segment, ensuring blood supply to secondary branches. Moreover, the small ring structure allows the connected second ring structures 4 to have a relatively small axial movement space, so there will be no very obvious axial shortening, ensuring the stability of distal anchoring and enabling more precise coverage of the lesion area.

[0032] Furthermore, in this application, the multiple first annular structures 1 of the covered segment 3 are not connected by any other structures; they are simply sintered together into a whole using the cover 2, which has good flexibility. This reduces the constraints on the relative movement between adjacent first annular structures 1, improves bending performance, and allows the covered segment 3 to better match the complex anatomy of the branch arteries. Of course, the distance between the first annular structures 1 needs to be ensured, which is set according to different requirements.

[0033] The above configuration ensures the flexibility of the covered segment 3 and the connection stability of the uncovered segment. The two work together to meet the blood supply needs of the secondary branches.

[0034] The distal stent segment 5, through the winding ring 400, allows the second annular structure 4 to have a relatively small axial movement space, ensuring the stability of the distal anchorage of the covered stent. This prevents the distal end of the covered stent from being deformed by the force caused by the body's limb movements, breathing, muscle movements, etc., resulting in a stable connection, accurate coverage of the lesion area, and guaranteed blood supply.

[0035] Example 2, reference Figure 5 and Figure 6 As shown, when the second ring structure 4 is unfolded in plane, it is a wavy wire with crests and troughs. The crests and / or troughs of the wavy wire cross and wrap around to form a winding loop 400. A portion of the first annular structure 1 at the end of the film-coated section 3 is circumferentially inserted and sleeved in the winding ring 400 of the second annular structure 4 at the beginning of the distal support section 5.

[0036] This embodiment clarifies the specific location of the winding ring 400 and the specific connection form between the coated section 3 and the distal support section 5, providing a concrete, efficient, and reliable axial interlocking connection scheme that makes the anti-shortening effect more predictable and achievable. Specifically, the winding ring 400 not only connects the second annular structures 4 but also connects the coated section 3 and the distal support section 5. The entire coated support can be connected using the same structure, simplifying the structure while ensuring connection stability.

[0037] Furthermore, the winding ring 400 includes an arc portion 4001 and two line segments 4002, which are respectively connected to the two ends of the arc portion 4001; the two line segments 4002 are arranged intersectingly, and the intersection points fit together to form a socket space with the arc portion 4001.

[0038] In this embodiment, the core function of the arc portion 4001 is to define and provide a regular, geometrically defined fitting space. The size and shape of this space determine the dimensional compatibility and movement margin of the fitting components. A smooth, continuous arc-shaped guide surface ensures smooth fitting action, reduces friction and stress concentration, and the geometric constraints of the arc effectively limit the tendency of the fitted components to disengage radially, which is the physical basis for achieving reliable interlocking.

[0039] The intersecting segments 4002 are not simply parallel, but rather intersected with their intersection points fitting together. These intersections divert loads from the arc-shaped portion onto the two segments and then transfer them to the underlying wavy wire structure through the fitting points, preventing stress concentration and potential failure caused by single-point stress. The intersecting structure itself forms a node with torsional stiffness in three-dimensional space. When the covered stent is subjected to complex blood flow impacts within the blood vessel, potentially causing minute torsion, this intersection effectively resists such torsional deformation.

[0040] The cross-bonded segments are easy to achieve and control during the weaving process, forming naturally from the weaving path without the need for additional welding or binding steps. During subsequent heat treatment and shaping, the bonding points help maintain the intended shape of the structure, ensuring product consistency.

[0041] The geometry of the socket needs to be consistent, and a standardized, repeatable socket interface is defined by clearly defined arc sections and cross segments. The covered stent is subjected to pulsating loads from a heartbeat throughout its lifespan; simple rings or hooks may experience metal fatigue fracture at the root due to stress concentration. The design of the cross segments significantly improves the fatigue resistance of the connection point by optimizing the load path and dispersing stress. The cross-fitting structure increases the complexity of the contact surface, providing additional circumferential constraints and effectively suppressing this harmful fretting.

[0042] In Example 3, when the first annular structure 1 is unfolded in a plane, it is a wavy wire with crests and troughs. The width of the wavy wire is different in the length direction, that is, the spacing between the crests and troughs of the wavy wire is different; there is an angle difference in the circumferential direction between any two adjacent first annular structures 1.

[0043] It is important to understand that, in addition to the above-mentioned flexibility and stability of the distal connection, the performance requirements for covered stents also need to ensure their support. Therefore, specific limitations on support are provided in this implementation.

[0044] The stent involved in this embodiment may have different diameter characteristics in different application scenarios. For example, during access delivery, the stent is radially pressed into the delivery sheath and has a smaller diameter. After entering the target lesion location in the blood vessel, the delivery sheath can be removed, at which time the stent has a larger diameter after expansion. The stent material is usually a superelastic material, such as a superelastic metal material like nickel-titanium alloy, as well as other implantable polymer materials with superelastic characteristics. This application does not impose any specific material limitations on the stent; the above are just examples.

[0045] As an optional implementation method, refer to Figure 2 and Figure 3 As shown, the peaks and troughs of the first annular structure 1 can be considered as being formed by the connection of multiple Z-shaped units with unequal rod lengths. The unequal rod lengths achieve the unequal peak-to-trough spacing mentioned earlier. The unequal peak-to-trough spacing can be achieved as follows: Figure 2 As shown, the length of the Z-shaped unit gradually decreases from the center outwards, or it can gradually decrease from both ends towards the middle, or the length of the Z-shaped unit does not change gradually. Figure 3 Viewed from the perspective of the displayed 3D structural diagram, the design of the rods with unequal lengths presents a "one end larger than the other" characteristic in 3D. The first ring structure 1 can be made of nickel-titanium alloy wire, and the pattern can be achieved through a weaving process using certain tooling. Then, the support ring sample is prepared by heat treatment to shape it.

[0046] Furthermore, when the first annular structures 1 are arranged periodically along the axial direction, there is an angular difference θ between adjacent first annular structures 1 in the circumferential direction. They gradually shift in the circumferential direction according to the value of θ. For example, when θ = 60°, after the previous first annular structure 1 is fixed, the next first annular structure 1 is rotated 60° clockwise or counterclockwise in the circumferential direction based on the previous first annular structure 1. The next first annular structure 1 is then arranged in the same direction by rotating the corresponding angular difference θ.

[0047] This periodically changing tilt direction of the coated segment 3, combined with its "large at one end and small at the other" characteristic, allows its overall structure to form a continuous three-dimensional spiral or S-shaped deformation path, such as... Figure 4 As shown, instead of the traditional single-direction stacking design, the tilting directions of adjacent first annular structures 1 are varied by periodically rotating an angle difference θ. For example, when θ = 60°, every six annular structures 2 complete a 360° rotation cycle, and the tilting directions are evenly distributed in three-dimensional space, avoiding stress concentration. In addition, the spiral or S-shaped deformation path increases the deformation space of the support. The tilting directions of each first annular structure 1 are distributed along the spiral trajectory and are staggered with each other, reducing the probability of contact between adjacent structures.

[0048] Furthermore, θ is preferably 30°, 45°, 60°, 90°, 120°, and 180°, that is, for every 360 degrees, the number of the first annular structures 1 are 12, 8, 6, 4, 3, and 2, respectively. Figure 3 The number of vertices in the first ring structure 1 can be adjusted according to the support performance, and can be 6, 8, 10, 12, 14, or 16. The number of vertices corresponds to the number of peaks and troughs.

[0049] In Embodiment 4, for the structure in which multiple second ring structures 4 are interconnected via winding rings 400, the following specific interconnection method is also provided: Form 1, see appendix Figure 7 As shown, all the crests and troughs of the wavy wire are crossed and wound to form winding loops 400. Any two adjacent second ring structures 4 are configured such that the winding loop 400 at the crest of one second ring structure 4 is nested with the winding loop 400 at the trough of the other second ring structure 4.

[0050] Form 1 involves the connection of each peak and trough, forming a fully interlocked network structure that greatly restricts axial and circumferential displacement; it has the strongest resistance to shortening and is suitable for lesion sites with extremely high requirements for distal anchoring stability, such as the bifurcation of the iliac artery, where the rivet area ensures the length; the overall force is distributed, avoiding local stress concentration.

[0051] Form 2, for reference Figure 10 As shown, the wavy wire crosses and wraps at some crests to form a winding loop 400, and crosses and wraps at some troughs to form a winding loop 400. Any two adjacent second ring structures 4 are configured such that the winding loop 400 at the crest of one second ring structure 4 is connected to the trough of the other second ring structure 4.

[0052] Form 2 has a moderate connection point, providing necessary axial constraint while retaining a certain degree of flexibility, making it suitable for vascular segments with high curvature; it facilitates smooth blood flow in branch vessels and reduces the stimulation of the stent on the vessel wall; the number of winding rings is reduced, and the braiding and heat treatment processes are easier to control.

[0053] Form 3, for reference Figure 11 As shown, the wavy wire crosses and wraps at some of the crests to form a winding loop 400, and there are several crests between adjacent winding loops 400. Any two adjacent second ring structures 4 are configured such that the winding loop 400 at the crest of one second ring structure 4 is connected to the trough of the other second ring structure 4.

[0054] Type 3 has fewer connection points, and the stent is more flexible in the longitudinal direction, making it suitable for tortuous blood vessels; it maintains basic axial stability, and although the number of connection points is reduced, shortening can still be effectively controlled through peak-trough interlocking; it is suitable for long lesions, and can maintain structural consistency over long distances, avoiding excessive rigidity.

[0055] Form 4: The wavy wire crosses and rewinds at some of the troughs to form a winding loop 400, and there are several troughs between adjacent winding loops 400. Any two adjacent second ring structures 4 are configured such that the winding loop 400 at the trough of one second ring structure 4 is connected to the crest of the other second ring structure 4.

[0056] Form four, with its trough connection, allows for closer contact with the vessel wall, promoting apposition and endothelialization; it is suitable for eccentric or irregular vessels, and the connection point position is adjustable to adapt to asymmetrical anatomical structures.

[0057] Form 5: In the distal support segment 5, a third ring structure 6 is connected between two adjacent second ring structures 4; the third ring structure 6, when unfolded in plan, is a wavy wire with crests and troughs. The crests and troughs of the wavy wire constituting the third ring structure 6 can be equally spaced or unequally spaced; naturally, in the case of unequal spacing, the second ring structure 4 must also have a similar structural design, with the longer sections of the second ring structure 4 corresponding to the shorter sections of the third ring structure 6, so that the second ring structure 4 and the third ring structure 6 are connected in a straight line in the axial direction. The limitation in this application regarding whether the crests and troughs of the wavy wire constituting the third ring structure 6 can be equally spaced or unequally spaced is merely a specific embodiment of this application, used to illustrate the technical solution of this application, and not to limit it. Those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

[0058] Form five is further divided into two cases: Scenario 1, see reference Figure 8 As shown: In the second annular structure 4, all the peaks and troughs are cross-wound to form winding loops 400. The third annular structure 6 and the two second annular structures 4 are configured such that the winding loop 400 at the trough of one of the second annular structures 4 is connected to the peak of the third annular structure 6, and the winding loop 400 at the peak of the other second annular structure 4 is connected to the trough of the third annular structure 6.

[0059] Scenario 2, see reference Figure 9 As shown: The wavy wire has some crests and some troughs that cross and rewind to form a winding loop 400. The third ring structure 6 and the two second ring structures 4 are configured such that: the winding loop 400 at the trough of one of the second ring structures 4 is connected to the crest of the third ring structure 6, and the winding loop 400 at the crest of the other second ring structure 4 is connected to the trough of the third ring structure 6.

[0060] Form 5's third ring structure 6 serves as a connecting bridge, smoothly transferring loads and reducing inter-segment torsion; it also allows for a gradual change in stiffness at the distal segment, optimizing mechanical matching. It should be noted that the above combinations only list possible scenarios, and the number and combination of stent rings required can be mixed and matched depending on the length of the uncovered bare stent segment, but this does not mean that the above combinations are the only possible combinations. For example, clinical application selection recommendations: If the blood vessels at the lesion site are relatively straight and high stability is required, form one or form five is preferred. If the blood vessels are significantly tortuous and flexibility is also required, form two or three, or form five, case two, is preferred. If the lesion is long and a balance between performance and cost is required, form two or three is more suitable. If there is external pressure or pulsating load, Form 5 is recommended to enhance durability.

[0061] in addition, Figure 8 and Figure 9 The connection form also demonstrates the connection form between the second ring structure 4 and the first ring structure 1.

[0062] As an optional implementation, a lining 2 is used, with the lining material including one or a combination of fluoropolymers, polytetrafluoroethylene, silicone, urethane, polyethylene, and aramid fibers. This addresses the issues of stent irritation to the vessel wall under certain circumstances, as well as stent sealing and prevention of blood leakage. The lining provides a smoother contact between the stent and the vessel wall, reducing mechanical irritation and the risk of vessel wall damage. Furthermore, the selection of the lining material considers biocompatibility and durability, ensuring long-term stability of the stent in vivo. Secondly, the lining effectively prevents excessive deposition of blood cells and proteins on the stent surface, reducing the risk of thrombosis. The diversity and combination of lining materials allow for stent customization based on different clinical needs; for example, silicone can be used in areas requiring greater flexibility, while fluoropolymers can be used in areas requiring greater corrosion resistance. This material flexibility provides more possibilities for stent design, better adapting to different patients' vascular conditions and lesion types. Finally, the lining can also enhance the radial support of the stent to some extent, improving its overall performance and enabling it to more effectively maintain vascular patency after implantation, reducing restenosis.

[0063] As an optional implementation, the fabrication process of the stent in this application includes the following steps: For multiple first ring structures 1, appropriate tooling is used to achieve the following through a weaving process: Figure 2 The planar unfolding is then used to connect the two ends of the planar unfolding to form a coated segment 3 of a certain length. The connection methods include, but are not limited to, welding, fusion, and sintering. Finally, the shape is fixed by heat treatment. For multiple second ring structures 4, appropriate tooling is used to achieve the following through a weaving process: Figures 7-11 The middle plane is unfolded, and then its two ends are connected to form a distal support segment 5 with a certain length; finally, it is shaped by heat treatment.

[0064] Connect the distal stent segment 5 and the covered segment 3.

[0065] Alternatively, multiple first ring structures 1 and multiple second ring structures 4 can be woven simultaneously during the weaving stage, thus achieving connection.

[0066] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above embodiments are provided to illustrate the advantages of the technical solution of this patent. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Stents can be used to treat aneurysms and arterial dissections, as well as the reconstruction of related branches, such as the left subclavian artery, brachiocephalic artery, left common carotid artery, celiac trunk artery, mesenteric artery, renal artery, iliac artery, etc. They can also be used for arterial stenosis, such as coronary arteries, superficial femoral artery, carotid artery, etc. They can also be used in other interventional scenarios, such as placing a stent after endovascular puncture to treat portal hypertension.

[0067] This application presents a self-expanding covered stent with good flexibility and support, consisting of a covered segment and a bare stent segment without a covered segment. It can effectively address the insufficient clinical application of branch artery reconstruction during endovascular treatment of aortic diseases, better match the complex anatomy of branch arteries, and provide sufficient support and anti-compression performance after deployment, increasing the patency of reconstructed branch vessels. The non-covered segment of the covered stent has a ring structure connection with cross-winding, effectively avoiding stent shortening, achieving extension of the distal rivet area and smooth blood flow to the branch, and significantly improving the clinical efficacy of endovascular repair of branch vessels.

[0068] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0069] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0070] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0071] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0072] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0073] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A covered stent, characterized in that, It includes: Multiple first annular structures (1) are distributed along the axial direction and connected to form a covered segment (3) by a covering film (2). Multiple second ring structures (4) are distributed along the axial direction; at least one of the two ends of the second ring structure (4) has a plurality of winding rings (400); any two adjacent second ring structures (4) are nested together through the winding rings (400) to form a distal support segment (5). The first annular structure (1) at the end of the film-coated section (3) is connected to the second annular structure (4) at the beginning of the distal support section (5) by a winding ring (400).

2. The covered stent as described in claim 1, characterized in that: When the second ring structure (4) is unfolded in a plane, it is a wavy wire with crests and troughs. The crests and / or troughs of the wavy wire cross and wrap around to form the winding ring (400). A portion of the first annular structure (1) at the end of the film-coated section (3) is circumferentially inserted and sleeved in the winding ring (400) of the second annular structure (4) at the beginning of the distal support section (5).

3. The covered stent as described in claim 1, characterized in that: When the first annular structure (1) is unfolded in a plane, it is a wavy wire with crests and troughs, and the spacing between the crests and troughs of the wavy wire is different. Any two adjacent first ring structures (1) have an angular difference in the circumferential direction.

4. The covered stent as described in claim 1 or 2, characterized in that: The winding ring (400) includes an arc portion (4001) and two line segments (4002), the two line segments (4002) being connected to the two ends of the arc portion (4001) respectively; the two line segments (4002) are arranged crosswise, and the intersection points fit together to form a socket space with the arc portion (4001).

5. The covered stent as described in claim 2, characterized in that: All the crests and troughs of the wavy wire are crossed and wound to form winding loops (400). Any two adjacent second ring structures (4) are configured such that the winding loop (400) at the crest of one second ring structure (4) is nested with the winding loop (400) at the trough of the other second ring structure (4).

6. The covered stent as described in claim 2, characterized in that: The wavy wire is partially crossed at the crests to form a winding loop (400), and partially crossed at the troughs to form a winding loop (400). Any two adjacent second ring structures (4) are configured such that the winding loop (400) at the crest of one second ring structure (4) is connected to the trough of the other second ring structure (4).

7. The covered stent as described in claim 2, characterized in that: The wavy wire crosses and wraps at some of the crests to form a winding loop (400), and there are several crests between adjacent winding loops (400). Any two adjacent second ring structures (4) are configured such that the winding loop (400) at the crest of one second ring structure (4) is connected to the trough of the other second ring structure (4).

8. The covered stent as described in claim 2, characterized in that: The wavy wire crosses and wraps at some of the troughs to form a winding loop (400), and there are several troughs between adjacent winding loops (400). Any two adjacent second ring structures (4) are configured such that the winding loop (400) at the trough of one second ring structure (4) is connected to the crest of the other second ring structure (4).

9. The covered stent as described in claim 2, characterized in that: A third ring structure (6) is also connected between any two adjacent second ring structures (4) in the distal support segment (5); the third ring structure (6) is a wavy wire with crests and troughs when unfolded in a plane.

10. The covered stent as described in claim 9, characterized in that: The second annular structure (4) has all its peaks and troughs intersected to form winding loops (400); or, the wavy wire has some of its peaks and some of its troughs intersected to form winding loops (400). The third ring structure (6) and the two second ring structures (4) are configured such that the winding ring (400) at the trough of one of the second ring structures (4) is connected to the crest of the third ring structure (6), and the winding ring (400) at the crest of the other second ring structure (4) is connected to the trough of the third ring structure (6).

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