Covered stent

Abstract

The invention provides a covered stent. The covered stent comprises a cutting stent and a covering film partially covering the cutting stent. The cutting support comprises a plurality of wave rings which are sequentially connected in the axial direction of the wave rings, and each wave ring comprises a plurality of foundation structures which are sequentially connected in the circumferential direction. The plurality of wave rings comprise z-shaped wave rings and double-n-shaped wave rings, and the z-shaped wave rings and the double-n-shaped wave rings are alternately arranged in the axial direction of the cutting support; the basic structure in the z-shaped wave ring is a first basic structure; the basic structure in the double-n-shaped wave ring is a second basic structure, and the second basic structure is a closed grid and is formed by butt joint of two n-shaped wave rods in the circumferential direction in a face-to-face mode. The covered stent has enough supporting performance, flexibility and adherence, internal leakage can be prevented, the thickness of the stent can be well controlled, and the covered stent can be conveyed and enter smaller blood vessels.

Description

Technical Field

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

[0002] Cardiovascular and cerebrovascular diseases are significant health threats, with aneurysms being the most common and constantly threatening human well-being. Covered stents, with their inherent advantage of immediate closure, have become increasingly widely used, especially in areas such as the thoracic aorta, abdominal aorta, heart valves, and carotid arteries, to isolate aneurysms and guide blood flow along the normal blood vessels.

[0003] However, most current covered stents are fully covered, with the stent completely covered by a cladding, or they use a double-layer cladding. Full cladding can affect the stent's flexibility and elasticity, and the cladding is prone to rupture, reducing its effectiveness. Double-layer cladding significantly increases the stent thickness, hindering stent delivery and entry into smaller vessels. Existing covered stents are also difficult to retrieve and reposition; if the deployment location is inaccurate, the covered stent can easily fail to adhere to the vessel wall proximally and obstruct branch vessels. Therefore, it is necessary to further improve covered stents, enhancing their performance in all aspects to achieve superior overall performance.

[0004] It should be noted that the information disclosed in the background section of this application is intended only to enhance the understanding of the general background of this application, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a covered stent with sufficient support, flexibility and wall adhesion, which can better fit the blood vessel wall, prevent endoleak, and better control the stent thickness in the radial direction, so that the covered stent can be delivered and inserted into smaller blood vessels.

[0006] To achieve the above objectives, the present invention provides a covered stent, comprising a cut stent and a covering film partially covering the cut stent;

[0007] The cutting bracket includes several corrugated rings connected sequentially along its own axis, and each corrugated ring includes multiple basic structures connected sequentially along the circumferential direction.

[0008] The plurality of wave loops include a zigzag wave loop and a double n-shaped wave loop, the zigzag wave loop and the double n-shaped wave loop being alternately arranged along the axial direction of the cutting bracket;

[0009] The basic structure in the Z-shaped waveguide is the first basic structure; the basic structure in the double n-shaped waveguide is the second basic structure, which is a closed grid formed by two n-shaped wave rods facing each other circumferentially.

[0010] Optionally, at least a portion of the zigzag wavering coil is embedded with an auxiliary support rod, which is disposed between two adjacent wavering rods in the zigzag wavering coil. One end of the auxiliary support rod is fixed to a wavering rod in the zigzag wavering coil, and the other end of the auxiliary support rod is a free end facing the distal end of the cutting bracket.

[0011] Optionally, the auxiliary support rods are circumferentially staggered in the zigzag wave, and / or the auxiliary support rods are circumferentially aligned in the zigzag wave.

[0012] Optionally, only one auxiliary support rod is provided between two adjacent wave rods in the zigzag wavering. The auxiliary support rod has a V-shaped structure, and the two branches of the V-shaped structure are fixed to the two adjacent wave rods in the zigzag wavering, respectively. The intersecting ends of the two branches are free ends and face the far end of the cutting bracket.

[0013] Optionally, several of the auxiliary support rods are evenly distributed in at least a portion of the zigzag wave coil.

[0014] Optionally, the portion of the cutting support exposed outside the coating is the bare segment, the portion of the cutting support covered by the coating is the coated segment, the proximal end and / or distal end of the cutting support is the bare segment, and the auxiliary support rod is only provided in the coated segment and / or the proximal end of the cutting support.

[0015] Optionally, the wavelength of the auxiliary support rod is smaller than the wavelength of the wave rod in the zigzag wavering, and the ratio of the wavelength of the wave rod in the zigzag wavering to the wavelength of the auxiliary support rod is 1.6:1.

[0016] Optionally, the cutting bracket is an overall closed-loop structure, or at least a portion of the cutting bracket is a unidirectional open-loop structure.

[0017] Optionally, the middle region of the cutting support, excluding the proximal and distal ends, is a unidirectional open-loop structure, while the proximal and distal ends of the cutting support are both closed-loop structures.

[0018] Optionally, the plurality of said wave loops may also include a diamond-shaped wave loop, wherein the proximal end of the cutting bracket employs the diamond-shaped wave loop.

[0019] Optionally, the portion of the cutting support exposed outside the coating is the bare segment, and the portion of the cutting support covered by the coating is the coated segment. The width of the n-shaped wave rod is smaller than the width of the wave rod in the zigzag wavering, and the ratio of the width of the wave rod in the zigzag wavering to the width of the n-shaped wave rod is (1.3-1.8):1. The width of the n-shaped wave rod in the bare segment is larger than the width of the n-shaped wave rod in the coated segment, and the ratio of the width of the n-shaped wave rod in the bare segment to the width of the n-shaped wave rod in the coated segment is (1.1-1.5):1.

[0020] Optionally, the width of the n-shaped wave rod is 20μm to 80μm, and the width of the wave rod in the z-shaped wave coil is 40μm to 100μm.

[0021] Optionally, the top end of the n-shaped wave rod is connected by an arc, the radius of which is 0.1mm to 5.0mm.

[0022] Optionally, the wavelength of the wave rod in the zigzag wavering is greater than the wavelength of the n-shaped wave rod, and the widths of the two n-shaped wave rods in the second basic structure are equal.

[0023] Optionally, the coating covers the outside of the cutting bracket, the coating is connected to the cutting bracket only at both ends, and the two ends of the coating are respectively heat-fused to multiple membranes, all of which are disposed in the cavity of the cutting bracket and adhere to the inner surface of the cutting bracket.

[0024] Optionally, all of the diaphragms cover the zigzag wavering, and / or each diaphragm is slidably connected to the wavering rod covering the diaphragm, and each diaphragm is blocked by reinforcing rings at the two closed ends of the wavering rod covering the diaphragm.

[0025] The film-coated scaffold provided by the present invention has at least the following advantages:

[0026] The aforementioned coated support includes a cutting support and a coating that partially covers the cutting support; the cutting support includes a plurality of waverings connected sequentially along its own axial direction, each wavering including a plurality of base structures connected sequentially along the circumferential direction; the plurality of waverings include zigzag waverings and double n-shaped waverings, the zigzag waverings and the double n-shaped waverings being alternately arranged along the axial direction of the cutting support; the base structure in the zigzag wavering is a first base structure; the base structure in the double n-shaped wavering is a second base structure, the second base structure being a closed grid formed by two n-shaped waverings circumferentially facing each other.

[0027] This configuration serves several purposes. First, the double n-shaped wave loops enhance the flexibility and flexural adhesion of the covered stent, preventing endoleak. Second, the z-shaped wave loops ensure the support and anchoring performance of the covered stent. Third, because the covering is single-layered and localized, it reduces the impact of the covering on stent cutting, further ensuring the flexibility of the covered stent and effectively reducing the risk of covering damage caused by stent expansion and contraction, thus ensuring the effectiveness of the covering. At the same time, it allows for better control of stent thickness, enabling the covered stent to be delivered and inserted into smaller blood vessels. Ultimately, the covered stent achieves superior overall performance by balancing multiple aspects.

[0028] In a further improvement, at least a portion of the Z-shaped corrugated coil incorporates an auxiliary support rod. This auxiliary support rod is positioned between two adjacent corrugated rods within the Z-shaped corrugated coil to increase the stability of the support structure and further enhance the support and anchoring performance of the coated support structure. Furthermore, one end of the auxiliary support rod is fixed to a corrugated rod in the Z-shaped corrugated coil, while the other end is a free end pointing towards the distal end of the cutting support structure. This arrangement ensures that the auxiliary support rod does not interfere with the retrieval and repositioning of the support structure. Especially for the coated section, the auxiliary support rod provides better support for the coated section, preventing the coated section from embedding into the cutting support structure and thus better preventing internal leakage. Attached Figure Description

[0029] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0030] Figure 1 This is a schematic diagram of the overall structure of the circumferential 4-wave cutting bracket in a preferred embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the overall structure of the circumferential 4-wave covered support in a preferred embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the overall structure of the circumferential 6-wave covered stent in a preferred embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the planar unfolded structure of the Z-shaped wave ring of the cutting bracket in a preferred embodiment of the present invention, in which auxiliary support rods are provided between adjacent wave rods and the auxiliary support rods are staggered circumferentially.

[0034] Figure 5 This is a schematic diagram of the planar unfolded structure of the circumferential 6-wave film-coated bracket without auxiliary support rods in a preferred embodiment of the present invention;

[0035] Figure 6 for Figure 5 Enlarged view of a portion of the structure;

[0036] Figure 7 This is a schematic diagram of the positional structure of the diaphragm on the cutting bracket in a preferred embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of a reinforced ring blocking diaphragm structure in a preferred embodiment of the present invention;

[0038] Figure 9 This is a schematic diagram of the planar unfolded structure of the circumferential 8-wave coated support in a preferred embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the planar unfolded structure of the circumferential 6-wave coated support in the preferred embodiment of the present invention, in which auxiliary support rods are provided between adjacent wave rods in the Z-shaped wave ring and the auxiliary support rods are circumferentially aligned.

[0040] Figure 11 This is a schematic diagram showing the dimensions of the cutting bracket in a preferred embodiment of the present invention;

[0041] Figure 12 This is a schematic diagram of the planar unfolded structure of the proximal end of the covered stent in a preferred embodiment of the present invention, which adopts a diamond-shaped corrugated ring.

[0042] Figure 13 This is a schematic diagram of a planar unfolded structure in a preferred embodiment of the present invention, where the middle region of the covered stent is a unidirectional open loop and the proximal and distal ends are closed loops.

[0043] The reference numerals in the attached drawings are as follows: 10-cutting bracket; 11-bare section; 12-coated section; 110-zigzag wavering; 111-first basic structure; 112-wavering rod; 113-reinforcing ring; 120-connecting rod; 130-double n-shaped wavering; 131-second basic structure; 132-n-shaped wavering; 133-arc; 140-auxiliary support rod; 160-diaphragm wavering; 20-coated; 30-diaphragm. Detailed Implementation

[0044] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the actual number, shape, and size of components in the actual implementation. In the actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0045] Furthermore, while each embodiment described below possesses one or more technical features, this does not imply that users of the present invention must simultaneously implement all technical features in any embodiment, or can only separately implement some or all technical features in different embodiments. In other words, provided it is feasible, those skilled in the art can, based on the disclosure of the present invention and depending on design specifications or implementation requirements, selectively implement some or all technical features in any embodiment, or selectively implement a combination of some or all technical features in multiple embodiments, thereby increasing the flexibility in implementing the present invention.

[0046] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “multiple” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated, and the terms “installed,” “connected,” and “linked” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Connections can be mechanical or electrical. Connections can be direct or indirect through an intermediate medium, and can be internal communication between two elements or an interaction between two elements. Relational terms such as “first,” “second,” etc., are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor do they indicate or imply relative importance or implicitly specify the number of indicated technical features. 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," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present 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, and therefore should not be construed as a limitation of the present invention. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances. The term "several" means an indefinite quantity.

[0047] In this application, "axial" refers to the direction along the central axis of the covered stent, i.e., the length direction of the covered stent; "circumferential" refers to the direction around the central axis of the covered stent; and "radial" refers to the direction perpendicular to the central axis of the covered stent, i.e., the diameter direction of the covered stent. In this application, "proximal end" refers to the end of the covered stent closest to the operator during delivery; and "distal end" is the end opposite to "proximal end," typically referring to the end of the covered stent furthest from the operator during delivery. In this application, the dimensions of the covered stent are all dimensions of the covered stent in its natural state.

[0048] The core idea of ​​this invention is to provide a covered stent that improves the support, flexibility, and flexural adherence to the vessel wall by optimizing the waveform of the stent cutting process, while preventing endoleak. Furthermore, the covered stent of this invention employs a closed-loop design overall or at least a unidirectional open-loop design in at least a partial area, allowing for stent retrieval and repositioning, thereby solving the problem of distal obstruction of branch vessels by the covered stent.

[0049] The covered stent provided by this invention can expand on its own or with the aid of external force, without any requirement. In actual use, the covered stent has a folded and contracted state and an expanded and contracted state, and can switch between the two states.

[0050] The following is a further explanation with reference to the accompanying drawings.

[0051] Please refer to Figures 1 to 13 As shown, the covered stent provided by the present invention includes a cutting stent 10 and a covering 20 that partially covers the cutting stent 10. The cutting stent 10 is made of various commonly used metal materials or polymers, typically stainless steel, nickel-titanium alloys, and other metal materials. The covering 20 is made of various commonly used membrane materials (polymers), and the specific material is not limited. The cutting stent 10 is not limited in its preparation method and is usually laser-engraved from a tube. The cutting stent 10 has an overall mesh-like structure for adhering to the inner wall of the blood vessel. The two ends of the cutting stent 10 (i.e., the proximal end and the distal end) can be designed as straight or flared. In this embodiment, both ends of the cutting stent 10 are flared, which is beneficial to increase the anchoring and wall-adhering performance of the stent ends.

[0052] The covering 20 can cover part of the outer surface or part of the inner surface of the cutting stent 10. In this embodiment, the covering 20 covers part of the outer surface of the cutting stent 10. Therefore, in terms of the covering method, the present invention uses a single-layer covering 20, and the cutting stent 10 is partially covered by the covering 20. This can reduce the restraint of the covering 20 on the cutting stent 10, and also prevent problems such as tearing of the covering 20, ensuring the flexibility of the covered stent and the effectiveness of the covering 20, and better controlling the stent thickness, so that the covered stent can be delivered and inserted into smaller blood vessels.

[0053] Please refer to Figures 1 to 3 As shown, according to the covering 20, the cutting stent 10 is divided into a bare segment 11 and a covered segment 12. The portion of the cutting stent 10 exposed outside the covering 20 is the bare segment 11, and the portion of the cutting stent 10 covered by the covering 20 is the covered segment 12. At least one of the proximal and distal ends of the cutting stent 10 is the bare segment 11. In this embodiment, both the proximal and distal ends of the cutting stent 10 are bare segments 11. Optionally, the length of the covered segment 12 is suitable for various lesion lengths, such as various aneurysms. Preferably, the length of the covered segment 12 is 4mm to 30mm; designing the covered segment 12 according to this length allows the covered stent to isolate most of the aneurysm, ensuring its applicability. The bare segment 11 at the distal end of the cutting stent 10 should not be too long, otherwise it may easily obstruct branch vessels.

[0054] Please refer to Figures 4 to 13 As shown, the cutting bracket 10 includes several corrugated rings connected sequentially along its own axial direction. Each corrugated ring includes multiple base structures connected sequentially along its circumference. The specific number of base structures is not limited. Optionally, each corrugated ring includes 3 to 10 base structures, more preferably 4 to 8 base structures. As illustrated in the figure, each corrugated ring includes 4 base structures (see figure). Figure 4 , Figure 13 ) or 6 basic structures (see Figure 5 , Figure 7 , Figure 10 , Figure 12 ) or 8 basic structures (see Figure 9 However, this is not the only applicable definition. Those skilled in the art will understand that the basic structure refers to the smallest structural unit of the same shape that repeats on the same wavering.

[0055] Furthermore, the plurality of wave loops includes a zigzag wave loop 110 and a double n-shaped wave loop 130, which are alternately arranged along the axial direction of the cutting bracket 10. The basic structure of the zigzag wave loop 110 is a first basic structure 111 (see details). Figure 6 Multiple first basic structures 111 are sequentially connected circumferentially to form a zigzag wave loop 110. This zigzag wave loop 110 is a wave-shaped structure with crests and troughs. Wave rods 112 are formed between adjacent crests and troughs. Two wave rods 112 intersect along the extension direction to form the first basic structure 111. The first basic structure 111 is generally V-shaped. It should be noted that the wave rods 112 in the zigzag wave loop 110 can extend straight, arc-shaped, or curved. In addition, the basic structure in the double n-shaped wave loop 130 is a second basic structure 131. Multiple second basic structures 131 are sequentially connected circumferentially to form a double n-shaped wave loop 130. Each second basic structure 131 is a closed grid and consists of two n-shaped wave rods 132 (in Figure 6 (Highlighted by detail a) Circumferential face-to-face docking is used. In this embodiment, the top of each n-shaped wave rod 132 is connected by an arc 133, allowing for greater freedom of movement.

[0056] Because the second base structure 131 has greater degrees of freedom, the covered stent exhibits better flexibility and wall-hugging properties, thus preventing internal leakage, which is more advantageous for the covered section 12. Simultaneously, the zigzag corrugated coil 110 provides sufficient support, ensuring the overall support and anchoring performance of the covered stent. Furthermore, the combination of single-layer and partial covering methods further enhances the overall performance of the covered stent.

[0057] It should be further explained that any two adjacent wave coils in the cutting bracket 10 are connected together by a connecting rod 120, which serves to support the bracket and reduce the probability of skewness. The connecting rod 120 can be bent, S-shaped, or straight, extending between two adjacent wave coils. Depending on the number of connecting rods 120, the cutting bracket 10 is divided into closed-loop and open-loop designs; an open-loop design is formed when the number of connecting rods 120 is less than the number of basic structures in the wave coils connected to the connecting rod 120; a closed-loop design is formed when the number of connecting rods 120 is equal to the number of basic structures in the wave coils connected to the connecting rod 120.

[0058] Optionally, the cutting support 10 has a closed-loop structure, specifically: all peaks or troughs in each zigzag corrugation 110 are connected to adjacent corrugations via connecting rods 120, enabling the coated support to be fully recovered and repositioned. In this embodiment, two adjacent corrugations can be a zigzag corrugation 110 and a double n-shaped corrugation 120, or a zigzag corrugation 110 and another zigzag corrugation 110, or a zigzag corrugation 110 and other corrugations of other shapes (such as a diamond-shaped corrugation 160).

[0059] Specifically, Figures 4 to 12 In the various examples described, each zigzag wave coil 110 is connected to the adjacent double n-shaped wave coil 120 via a connecting rod 120 to form a closed loop, so that the cutting bracket 10 as a whole is a closed loop structure.

[0060] Alternatively, at least a portion of the cutting stent 10 may be a unidirectional open-loop structure. Specifically, some areas of the cutting stent 10 may be unidirectional open-loop while other areas may be closed-loop, or the entire cutting stent 10 may be a unidirectional open-loop. A unidirectional open-loop structure can also achieve full recovery and repositioning of the coated stent, as long as the open-loop portion faces the distal end of the stent.

[0061] When the cutting support 10 adopts a unidirectional open-loop design, the open loop can be set at any one or more locations in the middle region, proximal end and distal end of the cutting support 10.

[0062] Given that the middle region of the cutting support 10 needs to have better flexibility than the two ends, it is preferable to have an open loop in the middle region of the cutting support 10 and closed loops at both ends. That is, the middle region of the cutting support 10, except for the proximal and distal ends, is a unidirectional open loop structure, while the proximal and distal ends are closed loop structures. Closed loops provide better support, which is beneficial for increasing the anchoring and wall-adhering performance at both ends of the support. When the proximal end of the cutting support 10 is a closed loop, it also facilitates force transmission, reduces pushing resistance, and better pushes the coated support.

[0063] Specifically, Figure 13 In the described exemplary embodiment, the bare segment 11 at the distal end of the cutting support 10 includes one zigzag corrugated coil 110, and the bare segment 11 at the proximal end includes two zigzag corrugated coils 110. Meanwhile, multiple zigzag corrugated coils 110 and multiple double-n-shaped corrugated coils 130 in the coated segment 12 are alternately arranged axially. At this time, the two zigzag corrugated coils 110 at the proximal end of the cutting support 10 are connected by a connecting rod 120 to form a closed loop, facilitating force transmission and better pushing of the coated support. Simultaneously, one zigzag corrugated coil 110 at the distal end of the cutting support 10 is connected to an adjacent double-n-shaped corrugated coil 130 in the coated segment 12 via the connecting rod 120 to form a closed loop, providing sufficient support force. All zigzag corrugated coils 110 and adjacent double-n-shaped corrugated coils 130 in the coated segment 12 are connected by the connecting rod 120 to form a unidirectional open loop. One-way open loop refers to the unconnected peaks or troughs in the zigzag wave loop 110 pointing towards the distal end of the stent. This one-way open loop does not affect the retrieval and repositioning of the stent.

[0064] refer to Figure 4 and Figures 10-11 In a further improvement, at least a portion of the zigzag wave coil 110 is embedded with an auxiliary support rod 140. The auxiliary support rod 140 is positioned between two adjacent wave rods 112 in the zigzag wave coil 110. One end of the auxiliary support rod 140 is fixed to the wave rod 112 in the zigzag wave coil 110, and the other end is a free end facing the far end of the cutting bracket 10.

[0065] The auxiliary support rod 140 of this invention provides more connection points to increase the stability of the support structure and further improve the support and anchoring performance of the coated support structure. Simultaneously, the other end of the auxiliary support rod 140 is a free end forming an open loop that extends towards the distal end of the support structure, thus not affecting the retrieval and repositioning of the support structure. For the coated section 12, the auxiliary support rod 140 can further support the coated film 20, preventing the coated film 20 from embedding into the cutting support structure 10, avoiding the collapse of the coated film 20, and better preventing internal leakage. Optionally, the auxiliary support rod 140 can be provided only in the coated section 12, or only in the proximal end of the cutting support structure 10, or only in the proximal end of the cutting support structure 10 and the coated section 12.

[0066] The auxiliary support rod 140 can have any construction, including but not limited to the V-shaped structure described in the figure, such as a W-shape, C-shape, etc. In this embodiment, when the auxiliary support rod 140 adopts a V-shaped structure, the structure is simpler, the processing and manufacturing are more convenient, and the pushing resistance can be minimized. Specifically, the two branches of the V-shaped structure are respectively fixed to two adjacent wave rods 112 in the Z-shaped wave coil 110. The intersecting ends of the two branches of the V-shaped structure are free ends and face the far end of the cutting bracket 10, so that the V-shaped structure forms a unidirectional open-loop design without affecting the retrieval and repositioning of the bracket.

[0067] In specific implementation, one or more auxiliary support rods 140 can be set between two adjacent wave rods 112 in the zigzag wave coil 110. However, when setting auxiliary support rods 140, the pushing resistance should be minimized as much as possible. For example, the number should not be too large. It is best to set only one auxiliary support rod 140 between two adjacent wave rods 112 in the zigzag wave coil 110.

[0068] Furthermore, the specific number and location of the auxiliary support rods 140 can be set according to actual needs, and are not limited to... Figure 4 and Figure 10 The situation described herein. Typically, a certain number of auxiliary support rods 140 are distributed across multiple zigzag corrugations 110, thereby providing more connection points. These auxiliary support rods 140 are distributed uniformly or non-uniformly in each zigzag corrugation 110. More preferably, the auxiliary support rods 140 are evenly distributed in the zigzag corrugations 110 to ensure uniform stress on the support and better bending performance. Furthermore, when setting the auxiliary support rods 140, they can be circumferentially staggered or circumferentially aligned in the zigzag corrugations 110, and both can exist simultaneously. Circumferential staggering means that the auxiliary support rods 140 are not distributed in the same zigzag corrugation 110 and have different axial positions; circumferential alignment means that the auxiliary support rods 140 are set in the same zigzag corrugation 110 and have the same axial position. Circumferential staggering provides more connection points, resulting in better stability of the support. An illustrative description follows.

[0069] Figure 4 In the described exemplary embodiment, a plurality of auxiliary support rods 140 are arranged between adjacent wave rods 112 in a plurality of zigzag wave coils 110, and some of the auxiliary support rods 140 are arranged on both sides of the same zigzag wave coil 110 to achieve a circumferentially staggered arrangement.

[0070] Figure 10 In the described exemplary embodiment, a plurality of auxiliary support rods 140 are arranged between adjacent wave rods 112 in a plurality of zigzag wave coils 110, and... Figure 4 The difference is, Figure 10 In the middle, the auxiliary support rods 140 are circumferentially aligned in each of the zigzag wave coils 110, and the overall distribution is relatively uniform.

[0071] To go further, Figure 4 In this design, both the zigzag wavering 110 and the double n-shaped wavering 130 include four basic structures. Except for the zigzag wavering 110 at the farthest end of the cutting bracket 10, each of the other zigzag waverings 110 has a V-shaped auxiliary support rod 140 between its adjacent wavering rods 112. The auxiliary support rods 140 distributed in the middle region are circumferentially staggered, but the auxiliary support rods 140 embedded in the zigzag wavering 110 at the closest end of the cutting bracket 10 are circumferentially aligned. Therefore, circumferential staggering and circumferential alignment can be implemented simultaneously.

[0072] It should also be understood that the corrugation near the end of the cutting support 10 can be either a zigzag corrugation 110 or... Figure 12 The diamond-shaped corrugation 160 is used at the proximal end of the cutting support 10. This facilitates force transmission during support transport and helps reduce pushing resistance. For the distal end of the cutting support 10, the corrugation shape is not specifically limited. In this embodiment, a zigzag corrugation 110 is used at the distal end of the cutting support 10 to ensure the support and wall adhesion performance of the distal end of the coated support.

[0073] Furthermore, to improve the transport and conduction properties of the cut stent 10, the width of the n-shaped corrugated rod 132 in the bare section 11 is thicker than that in the coated section 12, but the width of the n-shaped corrugated rod 132 is smaller than that of the corrugated rod 112 in the zigzag corrugated coil 110. When the width of the n-shaped corrugated rod 132 is smaller than that of the corrugated rod 112 in the zigzag corrugated coil 110, the coated stent can bend smoothly at the double n-shaped corrugated coil 130 when bending, rather than at the zigzag corrugated coil 110, thus preventing the stent from "kinking".

[0074] Preferably, the ratio of the width of the wave rod 112 in the Z-shaped wave coil 110 to the width of the n-shaped wave rod 132 is (1.3-1.8):1; this setting provides optimal bending performance. Optionally, the ratio of the width of the wave rod 112 in the Z-shaped wave coil 110 to the width of the n-shaped wave rod 132 is 1.3:1, 1.5:1, or 1.8:1. More preferably, the ratio of the width of the n-shaped wave rod 132 to the width of the wave rod in the Z-shaped wave coil 110 is 1:1.5.

[0075] Preferably, the ratio of the width of the n-shaped wave rod 132 in the bare section 11 to the width of the n-shaped wave rod 132 in the coated section 12 is (1.1-1.5):1; this setting is beneficial for force transmission. Optionally, the ratio of the width of the n-shaped wave rod 132 in the bare section 11 to the width of the n-shaped wave rod 132 in the coated section 12 is 1.1:1, 1.2:1, 1.3:1, 1.4:1, or 1.5:1.

[0076] Optionally, the wavelength of the wave rod 112 in the zigzag wave coil 110 is greater than the wavelength of the n-shaped wave rod 132 in the double n-shaped wave coil 130, which improves support and flexibility without significantly increasing pushing resistance. Optionally, the ratio of the wavelength of the wave rod 112 in the zigzag wave coil 110 to the wavelength of the n-shaped wave rod 132 in the double n-shaped wave coil 130 is in the range of (1.1~2.0):1, and the ratio can be 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1.

[0077] The widths of the two n-shaped wave rods 132 in the second basic structure 131 may be equal or unequal. Preferably, the widths of the two n-shaped wave rods 132 in the second basic structure 131 are equal to make the structure more uniform and improve its bending and wall-hugging properties.

[0078] Furthermore, the wavelength of the auxiliary support rod 140 is typically smaller than the wavelength of the wave rod 112 in the zigzag wave coil 110; that is, the wave height of the auxiliary support rod 140 is smaller than the wave height of the wave rod 112 in the zigzag wave coil 110. Thus, the smaller wave height and wavelength of the auxiliary support rod 140 prevent the coating 20 from embedding without increasing the pushing resistance. Preferably, the ratio of the wavelength of the wave rod 112 in the zigzag wave coil 110 to the wavelength of the auxiliary support rod 140 is 1.6:1, which has the advantage of ensuring bending and adhering to the wall without significantly increasing the pushing resistance.

[0079] It should be understood that the present invention further optimizes the structural dimensions of the cutting bracket 10, and when the ratio of the rod width to the wall thickness is 1:1, the performance of the coated bracket is better.

[0080] For more details, please refer to Figure 11 As shown, in some embodiments, the zigzag wave coil 110 meets the following dimensional requirements: wave height h is 0.4mm to 5.0mm, more preferably 0.5mm to 2.5mm; wavelength b is 0.8mm to 10mm, more preferably 1.5mm to 3.0mm; rod width is 40μm to 100μm, more preferably 50μm to 70μm; and the number of first basic structures 111 is 3 to 10, more preferably 4 to 6. These parameters optimize the support's bending and wall-hugging properties, support capacity, and pushing resistance.

[0081] In some embodiments, the double n-shaped wave coils 130 meet the following dimensional requirements: wave height h is 0.4mm to 5.0mm, more preferably 0.5mm to 2.5mm; wavelength b is 0.5mm to 8.0mm, more preferably 1.2mm to 2.5mm; rod width is 20μm to 80μm, more preferably 30μm to 50μm; the width ratio of the two n-shaped wave rods 132 is 1:1 to 1:8, more preferably 1:1; the radius of the arc of the n-shaped wave rod 132 (see the positions marked h1 and h2) is 0.1mm to 5.0mm, more preferably 0.4mm to 0.6mm; the number of second base structures 131 is 3 to 10, more preferably 4 to 6. These parameters optimize the support's bending and wall-hugging properties, support capacity, and pushing resistance.

[0082] In some embodiments, the auxiliary support rod 140 meets the following dimensional requirements: wave height h is 0.2mm to 3.0mm, more preferably 0.4mm to 1.0mm; wavelength b is 0.1mm to 5.0mm, more preferably 0.8mm to 2.0mm; rod width is 20μm to 80μm, more preferably 20μm to 40μm; and the number of circumferentially distributed rods is 0 to 10, more preferably 0 (equivalent to no auxiliary support rod 140). The above parameters can better provide better bending performance without significantly increasing the pushing resistance.

[0083] Preferably, the wave height (h) of the zigzag wave coil 110 is equal to the wave height (h) of the double n-shaped wave coil 130, the wavelength (b) of the zigzag wave coil 110 is greater than the wavelength (b) of the n-shaped wave rod 132, and the rod width of the zigzag wave coil 110 is greater than the rod width of the double n-shaped wave coil 130.

[0084] Preferably, the wave height (h) of the auxiliary support rod 140 is less than the wave height (h) of the zigzag wave coil 110, the wavelength of the auxiliary support rod 140 is also less than the wavelength (b) of the zigzag wave coil 110, and the width of the auxiliary support rod 140 is preferably the same as or less than the width of the n-shaped wave rod 132.

[0085] For the coated section 12, the width of the wave rod 112 in the first basic structure 111 of the zigzag wave coil 110 is preferably 40μm to 100μm, the width of the auxiliary support rod 140 is preferably 30μm to 90μm, and the width of the n-shaped wave rod 132 is 20μm to 80μm. Furthermore, the setting of the rod width preferably follows the ratio range mentioned above.

[0086] The following section will provide a more detailed explanation of how the film 20 is set up.

[0087] In practice, after the film 20 covers the cutting bracket 10, it is at least partially connected to the cutting bracket 10, which can be a fixed connection or a movable connection. Preferably, only both ends of the film 20 are connected to the cutting bracket 10, thereby reducing the restrictive effect of the film 20 on the cutting bracket 10 and also reducing the influence of the cutting bracket 10 on the film 20. The present invention does not impose any particular limitation on the connection method between the film 20 and the cutting bracket 10; for example, conventional suturing fixation or other connection methods can be used.

[0088] Please refer to Figure 7 and Figure 8 As shown, according to a preferred embodiment of this application, instead of sutures or a double-layer membrane, a single-layer covering 20 is thermally fused to the cutting stent 10 using multiple membranes 30. All membranes 30 are disposed only within the lumen of the cutting stent 10 and adhere to its inner surface. This arrangement achieves the bonding of the covering 20 and the cutting stent 10, minimizing the increase in stent thickness. This provides more favorable conditions for the covered stent to enter a small delivery system and reach more distal, smaller blood vessels. Furthermore, because the membranes 30 are located inside the cutting stent 10, they do not affect the stent's appearance. The membranes 30 are very small, much smaller than the covering 200; therefore, they add almost no thickness to the stent and have minimal impact on it. The thermal fusion of the membranes 30 with the outer covering 30 prevents stent deformation due to the covering 30, reducing the risk of stent deformation, improving reliability and stability, and resulting in superior performance. Compared with traditional lamination methods, the lamination method for small films (30mm) is simpler, easier to mechanize, and facilitates the simplification of the fabrication process for the lamination support, thereby improving production efficiency.

[0089] The diaphragm 30 can be thermally bonded to the outer coating 20 through the mesh on the cutting support 10. The diaphragm 30 can be made of various commonly used polymer materials, and the material of the diaphragm 30 may be the same as or different from that of the coating 20, but preferably the same.

[0090] Preferably, only both ends of the membrane 20 are thermally fused to multiple membrane sheets 30. During thermal fusion, the membrane 20 is kept flat, ensuring that the edges of the membrane 20 are completely fused with the membrane sheets 30. The multiple membrane sheets 30 connected to any end of the membrane 20 are distributed circumferentially along the cut support 10, such as uniformly or non-uniformly. The number of membrane sheets 30 connected to any end of the membrane 20 is not limited; however, the number of membrane sheets 30 should be minimized to control the support thickness while ensuring sufficient connection strength. Figure 7 The diagram shows a total of eight membranes 30, with four membranes 30 connected to each end of the covering membrane 20. In an alternative embodiment, fewer or more than four membranes 30 may be provided for connection to either end of the covering membrane 20.

[0091] The diaphragm 30 covers the wave rod 112 in the zigzag wavering coil 110, or it can cover the n-shaped wave rod 132 in the double n-shaped wavering coil 130. Since the wave rod 112 in the zigzag wavering coil 110 can provide greater force and is less prone to deformation, it is more suitable to cover all the diaphragms 30 on the wave rod 112 in the zigzag wavering coil 110. It should be noted that even if the diaphragm 30 is not used to fix the membrane 20, the two ends of the membrane 20 can be connected to the zigzag wavering coil 110 to better support the membrane 20.

[0092] The diaphragm 30 is fixedly connected to or movably connected to the wave rod 112 covering the diaphragm 30. Preferably, each diaphragm 30 is movably connected to the wave rod 112 covering the diaphragm 30, so that the diaphragm 30 can slide on the wave rod 112 but will not slip off the wave rod 112, allowing the coating 20 to move relative to the cutting support 10. Because the coating 20 can move relative to the cutting support 10, the cutting support 10 can better extend, contract, and bend, and the coating 20 is less prone to wrinkles, damage, or other problems.

[0093] like Figure 8 As shown, preferably, the diaphragm 30 is blocked directly by the reinforcing rings 113 (protruded by detail circle B) at the two closed ends of the wave rod 112, thus preventing large displacement of the diaphragm 30. The reinforcing rings 113 are the location of the connecting rod 120. This arrangement ensures that the two ends of the coating 20 can only move within a relatively small area, effectively fixing the relative position of the coating 20 on the cutting bracket 10.

[0094] In summary, compared with the prior art, the film-coated scaffold provided by the present invention has at least the following advantages:

[0095] (1) By using the double n-shaped wave coil 130, the flexibility and bending adhesion of the covered stent are improved, preventing endoleak. Combined with the z-shaped wave coil 110, the good support and anchoring ability of the stent are ensured. Furthermore, by using single-layer and localized covering methods, the impact of the covering 20 on the cutting stent 10 is reduced, further ensuring the flexibility of the covered stent and the effectiveness of the covering 20. The stent thickness is also controlled so that the covered stent can be delivered and enter smaller blood vessels, thus taking into account delivery performance.

[0096] (2) The support and anchoring force of the support are further increased by embedding auxiliary support rods 140 in at least part of the zigzag wave coils 110 without affecting the recovery and repositioning of the support.

[0097] (3) On the basis of ensuring anchoring force and wall adhesion, the overall recyclability and repositioning of the covered stent can be achieved through closed-loop or unidirectional open-loop design, and the blockage of branch vessels after the distal end of the covered stent is released can be avoided.

[0098] (4) By setting the length of the covered segment 12 to 4mm to 30mm, the covered stent can be used to isolate most aneurysms, ensuring its applicability.

[0099] (5) Instead of using sutures or double-layer coverings, a single covering 20 is thermally fused to the cutting stent 10 using multiple membranes 30. All membranes 30 are placed only in the lumen of the cutting stent 10, thereby achieving the combination of the covering 20 and the cutting stent 10. This can minimize the increase in stent thickness, provide conditions for the covered stent to enter the small delivery system and reach more distant small blood vessels, without affecting the appearance of the stent, and also reduce the impact of the covering on the stent, ensuring the flexibility of the stent.

[0100] (6) The reinforcing ring 113 is used to block the diaphragm 30, preventing large displacement of the diaphragm 30. This ensures that the two ends of the coating 20 can only move within a relatively small area, effectively fixing the relative position of the coating 20 on the support wave rod. The method of heat-melting the outer coating 20 of the diaphragm 30 prevents support deformation due to the coating 20, reducing the risk of support deformation, improving reliability and stability, and enhancing performance. Compared with traditional coating methods, the coating method of the diaphragm 30 is simpler, easier to mechanize, simplifies the manufacturing process of the coated support, and improves production efficiency.

[0101] Overall, the film-coated stent provided by the present invention can take into account various performance aspects, such as thickness, flexibility, anchoring, wall adhesion, recyclability, positioning performance, and conveying performance, making the overall performance of the film-coated stent better.

[0102] The above description is only a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the present invention.

Claims

1. A covered stent, characterized in that, Includes a cutting bracket and a coating that partially covers the cutting bracket; The cutting bracket includes several corrugated rings connected sequentially along its own axis, and each corrugated ring includes multiple basic structures connected sequentially along the circumferential direction. The plurality of wave loops include a zigzag wave loop and a double n-shaped wave loop, the zigzag wave loop and the double n-shaped wave loop being alternately arranged along the axial direction of the cutting bracket; The basic structure in the Z-shaped waveguide is the first basic structure; the basic structure in the double n-shaped waveguide is the second basic structure, which is a closed grid formed by two n-shaped wave rods facing each other circumferentially.

2. The covered stent as described in claim 1, characterized in that, At least a portion of the zigzag wave coil has an auxiliary support rod embedded in it. The auxiliary support rod is positioned between two adjacent wave rods in the zigzag wave coil. One end of the auxiliary support rod is fixed to a wave rod in the zigzag wave coil, and the other end of the auxiliary support rod is a free end facing the distal end of the cutting bracket.

3. The covered stent as described in claim 2, characterized in that, The auxiliary support rods are circumferentially staggered in the zigzag wave, and / or the auxiliary support rods are circumferentially aligned in the zigzag wave.

4. The covered stent as described in claim 2, characterized in that, In the Z-shaped wavering, only one auxiliary support rod is provided between two adjacent wave rods. The auxiliary support rod has a V-shaped structure. The two branches of the V-shaped structure are fixed to the two adjacent wave rods in the Z-shaped wavering, and the intersecting ends of the two branches are free ends and face the far end of the cutting bracket.

5. The covered stent as described in claim 2, characterized in that, Several of the auxiliary support rods are evenly distributed in at least a portion of the zigzag wave coil.

6. The covered stent as described in claim 2, characterized in that, The portion of the cutting support exposed outside the coating is the bare segment, the portion of the cutting support covered by the coating is the coated segment, the proximal end and / or distal end of the cutting support is the bare segment, and the auxiliary support rod is only provided in the coated segment and / or the proximal end of the cutting support.

7. The covered stent as described in claim 2, characterized in that, The wavelength of the auxiliary support rod is smaller than the wavelength of the wave rod in the zigzag wavering, and the ratio of the wavelength of the wave rod in the zigzag wavering to the wavelength of the auxiliary support rod is 1.6:

1.

8. The covered stent as described in claim 1 or 2, characterized in that, The cutting bracket is a closed-loop structure as a whole, or at least a portion of the cutting bracket is a unidirectional open-loop structure.

9. The covered stent as described in claim 1 or 2, characterized in that, The cutting support has a unidirectional open-loop structure in the middle region except for the proximal and distal ends, while the proximal and distal ends of the cutting support are both closed-loop structures.

10. The covered stent as described in claim 1 or 2, characterized in that, The wave loops also include a diamond-shaped wave loop, which is used at the proximal end of the cutting bracket.

11. The covered stent as described in claim 1 or 2, characterized in that, The portion of the cutting support exposed outside the coating is the bare segment, and the portion of the cutting support covered by the coating is the coated segment. The width of the n-shaped wave rod is smaller than the width of the wave rod in the zigzag wavering, and the ratio of the width of the wave rod in the zigzag wavering to the width of the n-shaped wave rod is (1.3-1.8):

1. The width of the n-shaped wave rod in the bare segment is larger than the width of the n-shaped wave rod in the coated segment, and the ratio of the width of the n-shaped wave rod in the bare segment to the width of the n-shaped wave rod in the coated segment is (1.1-1.5):

1.

12. The covered stent as described in claim 11, characterized in that, The width of the n-shaped wave rod is 20μm to 80μm, and the width of the wave rod in the z-shaped wave coil is 40μm to 100μm.

13. The covered stent as described in claim 1 or 2, characterized in that, The top end of the n-shaped wave rod is connected by an arc, the radius of which is 0.1mm to 5.0mm.

14. The covered stent as described in claim 1 or 2, characterized in that, The wavelength of the wave rod in the zigzag wavering is greater than the wavelength of the n-shaped wave rod, and the widths of the two n-shaped wave rods in the second basic structure are equal.

15. The covered stent as described in claim 1 or 2, characterized in that, The coating covers the outside of the cutting bracket. The coating is connected to the cutting bracket at only two ends, and the two ends of the coating are respectively heat-fused to multiple membranes. All the membranes are disposed in the cavity of the cutting bracket and fit against the inner surface of the cutting bracket.

16. The covered stent as described in claim 15, characterized in that, All of the diaphragms cover the zigzag wavering, and / or each diaphragm is slidably connected to the wavering rod covering the diaphragm, and each diaphragm is blocked by reinforcing rings at the two closed ends of the wavering rod covering the diaphragm.

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