Interventional stent and film covering method

Abstract

The invention provides an interventional stent and a film covering method. The interventional stent comprises a woven mesh pipe, a covering film and a plurality of connecting diaphragms, a plurality of woven wires of the woven mesh pipe intersect with one another to form grids and intersection points, all the connecting diaphragms are arranged in a pipe cavity of the woven mesh pipe, at least part of pipe sections of the woven mesh pipe are sleeved with the covering film, and the two axial ends of the covering film are connected with the connecting diaphragms distributed in the circumferential direction respectively. Each connecting diaphragm covers the weaving wire between two adjacent cross points, and the weaving wire covered with the connecting diaphragm is pressed on the other weaving wire at the corresponding cross point, so that the other weaving wire pressed by the weaving wire covered with the connecting diaphragm can block the connecting diaphragm in the axial stretching process of the interventional stent, and therefore, the connecting diaphragm can be inserted into the interventional stent in the axial stretching process of the interventional stent. Combination of the covering film and the woven mesh pipe is achieved, the thickness of the stent is prevented from being increased, and the flexibility and appearance of the stent are not affected.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and more specifically, to an interventional stent and a film covering method. Background Art

[0002] Cardiovascular and cerebrovascular diseases are important diseases affecting human health, among which aneurysms are the most common, constantly endangering human health. Due to its inherent advantage of being able to block, the covered stent has become a more and more widely used stent, especially applied to pathological locations such as the thoracic aorta, abdominal aorta, heart valve, carotid artery, etc., to isolate aneurysms and guide blood to flow along the direction of normal blood vessels.

[0003] Most current covered stents use sutures to combine the film with the stent. However, sutures are likely to increase the thickness of the stent, and the exposed suture ends will also affect the appearance. In addition, there are also covered stents with double-layer films, with film layers arranged both inside and outside the stent, and the inner and outer double-layer films are combined with the stent. This will greatly increase the thickness of the stent, thereby increasing the difficulty of the stent entering smaller blood vessels. At the same time, the inner and outer double-layer films are also likely to restrict the stent, affecting the flexibility and stretchability of the stent.

[0004] Therefore, for those skilled in the art, how to design an interventional stent that does not increase the thickness of the stent, does not affect the flexibility of the stent, and does not affect the appearance of the stent is a technical problem that needs to be solved urgently at present.

[0005] It should be noted that the information disclosed in the background art part of the present application is only intended to deepen the understanding of the general background art of the present application, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide an interventional stent and a film covering method to solve the problems of large stent thickness, poor flexibility, and easy influence on the appearance of the stent caused by the existing film covering technology.

[0007] To achieve the above purpose, the present invention provides an interventional stent, including a braided network tube, a film covering, and a plurality of connecting film pieces. The braided network tube is woven by a plurality of braided wires, and the plurality of braided wires intersect with each other to form grids and intersection points. All the connecting film pieces are arranged in the lumen of the braided network tube;

[0008] The film covering is sleeved on at least part of the tube section of the braided network tube. Axial ends of the film covering are respectively connected to the plurality of connecting film pieces. The plurality of connecting film pieces connected to any one end of the film covering are distributed in the circumferential direction of the braided network tube;

[0009] Each of the connecting diaphragms covers the braided wires between two adjacent intersections, and the braided wire covered with the connecting diaphragm presses on another braided wire at the corresponding intersection, so that the other braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm during the axial stretching of the interventional stent.

[0010] In one embodiment, each of the connecting diaphragms is not fixed to the braided wire covering it, and each of the connecting diaphragms only moves on the braided wires between two adjacent intersections it covers, and the other braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm in one direction.

[0011] In one embodiment, the film is sleeved on at least part of the braided network tube in a folded manner.

[0012] In one embodiment, the connecting diaphragm has an avoidance area and a fixing area. The fixing area is located on the periphery of the avoidance area. The connecting diaphragm is attached to the covered braided wire through the avoidance area, and the connecting diaphragm is heat-melted and connected to the film through the fixing area.

[0013] In one embodiment, the connecting diaphragm is rectangular.

[0014] In one embodiment, the length of the avoidance area is 1 / 4 to 1 / 3 of the total length of the connecting diaphragm, and the width of the avoidance area is equal to the width of the fixing area.

[0015] In one embodiment, the length of the connecting diaphragm is 0.2 mm to 5.0 mm, and the width of the connecting diaphragm is 0.2 mm to 5.0 mm.

[0016] In one embodiment, the material of the film is the same as the material of the connecting diaphragm.

[0017] In one embodiment, the interventional stent further has at least one of the following features:

[0018] A plurality of the connecting diaphragms connected to any one end of the film are sequentially arranged at intervals of N meshes in the circumferential direction of the braided network tube, and N is a natural number of zero or greater than zero;

[0019] A plurality of the connecting diaphragms connected to any one end of the film are sequentially distributed in the circumferential direction of the braided network tube, and the plurality of connecting diaphragms are aligned or staggered in the axial direction of the braided network tube;

[0020] The same connecting diaphragm covers one or more of the braided wires, and each braided wire covered with the connecting diaphragm is pressed against another braided wire at the corresponding intersection point.

[0021] In one embodiment, the braided network tube has a plurality of tube segments, which are a distal bare segment, a film-covered segment, and a proximal bare segment that are axially connected in sequence from the distal end to the proximal end. The film is sleeved on the film-covered segment and does not cover the distal bare segment and the proximal bare segment. Developing structures for positioning the film are provided at both the proximal and distal ends of the film-covered segment.

[0022] Based on the same inventive concept, the present invention also provides a film covering method for preparing an interventional stent, including:

[0023] Providing a braided network tube, which is woven from a plurality of braided wires, and the plurality of braided wires intersect with each other to form a grid and intersection points;

[0024] Sleeving a film on at least part of the tube segments of the braided network tube;

[0025] Connecting the axial two ends of the film to a plurality of connecting diaphragms respectively. All the connecting diaphragms are arranged in the lumen of the braided network tube, and the plurality of connecting diaphragms connected to any one end of the film are distributed circumferentially on the braided network tube;

[0026] Making each connecting diaphragm cover the braided wire between two adjacent intersection points, and making the braided wire covered with the connecting diaphragm press against another braided wire at the corresponding intersection point, so that the other braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm during the axial stretching process of the interventional stent.

[0027] In one embodiment, the film covering method further includes:

[0028] Making each connecting diaphragm not fixed to the braided wire covered by the connecting diaphragm, so that each connecting diaphragm can only move on the braided wire between two adjacent intersection points it covers, and making the other braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm in one direction.

[0029] Compared with the prior art, the interventional stent and the film covering method provided by the present invention have the following advantages:

[0030] In the above-mentioned interventional stent, first, both ends of the film are respectively connected to a plurality of connecting diaphragms which are circumferentially distributed in the lumen of the braided network tube. This film covering method can maximize the avoidance of increasing the stent thickness, and since the connecting diaphragms are arranged in the lumen, it does not affect the appearance of the interventional stent. Secondly, each connecting diaphragm covers the braided wires between two adjacent intersection points and does not cover the intersection points to avoid the influence of the intersection points on the connecting diaphragms. In addition, the braided wires covered with the connecting diaphragms are pressed on another braided wire at the corresponding intersection points, so that the other braided wire pressed by the braided wires covered with the connecting diaphragms can block the connecting diaphragms during the axial stretching process of the interventional stent. This can avoid large displacements of both ends of the film relative to the braided network tube, and then better fix the position of the film on the braided network tube. It can also prevent the film from gathering and wrinkling towards the midline due to the expansion and contraction of the braided network tube, thereby avoiding excessive wrinkles of the film causing thrombosis, and it is also convenient for the operator to determine the position of the film, and then accurately release the film at the lesion site, improving the surgical efficiency. Brief Description of the Drawings

[0031] Those of ordinary skill in the art will understand that the provided drawings are used to better understand the present invention and do not constitute any limitation to the scope of the present invention. Among them:

[0032] Figure 1 is a schematic diagram of the overall structure of the interventional stent in the preferred embodiment of the present invention;

[0033] Figure 2 is a schematic diagram of the partial structure of the interventional stent connecting the film through a plurality of connecting diaphragms in the preferred embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of the partial structure of the interventional stent positioning the film through the imaging structure in the preferred embodiment of the present invention, where the vertical line L represents the proximal edge of the film, and the part to the left of the proximal edge is the film. Detailed Description of the Embodiments

[0035] To make the objectives, advantages and features of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and not drawn to scale, and are only used to conveniently and clearly assist in explaining the objectives of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structures. In particular, the focuses to be shown in each drawing are different, and sometimes different scales are used. As used in this specification, the singular forms "a", "an" and "the" include plural objects unless the content clearly indicates otherwise. As used in this specification, the term "or" is generally used in the sense of including "and / or" unless the content clearly indicates otherwise.

[0036] In this application, "diameter" refers to "outer diameter", "axial direction" refers to the longitudinal axis direction of the interventional stent, "circumferential direction" refers to the direction around the longitudinal axis of the interventional stent, and "radial direction" refers to the direction perpendicular to the longitudinal axis of the interventional stent, that is, the diameter direction. In this application, "proximal end" refers to the end close to the surgeon during the delivery of the interventional stent; "distal end" refers to the end far from the surgeon during the delivery of the interventional stent. The "length" and "diameter" described in this article are the dimensions of the interventional stent in the expanded and dilated state.

[0037] The object of the present invention is to provide an interventional stent and its film covering method to solve the problems of large stent thickness, easy influence on stent flexibility and appearance when preparing film-covered stents in the prior art by suture and double-layer film covering.

[0038] The following is described with reference to the accompanying drawings. Although the following embodiments are described in combination with the treatment of aneurysms, it should be recognized that the interventional stent and its film covering method of the present invention can be used to treat many other diseases and should not be limited to this treatment.

[0039] As Figure 1 shown, the present invention provides an interventional stent, which is used as a film-covered stent. The interventional stent includes a braided network tube 10 and a film 20. The braided network tube 10 is woven by a plurality of braided wires 101, and the plurality of braided wires 101 intersect with each other to form a grid 102 and intersection points 103.

[0040] The interventional stent has a folded and contracted state and an expanded and dilated state, and can be switched between the folded and contracted state and the expanded and dilated state. Generally, when the interventional stent is delivered through a delivery system, it is in a folded and contracted state. In the folded and contracted state, the interventional stent is axially elongated, making its radial dimension smaller for easy delivery. After the interventional stent is released from the delivery system, it is in an expanded and dilated state. It should also be noted that when the interventional stent is not externally constrained, it is also in an expanded and dilated state, and the expanded and dilated state at this time is the natural state.

[0041] The braided network tube 10 is a common material, for example, it can be selected from one material or a combination of multiple materials such as cobalt-based alloys, stainless steels, nickel-titanium alloys, platinum alloys, iridium alloys, bioactive ceramics, and carbon, or a composite material of these materials. The film 20 is a common polymer material, such as expanded polytetrafluoroethylene (ePTFE), polyester (PET), polyurethane (TPU), polylactic acid (PLA), or other polymer materials.

[0042] The film coating 20 is sleeved on at least part of the pipe section of the braided network tube 10. Preferably, the film coating 20 is only sleeved on part of the pipe section of the braided network tube 10, and the remaining pipe sections of the braided network tube 10 are not provided with the film coating 20 to form bare sections. Thus, the film coating 20 is only provided on the outside of the braided network tube 10, and the film coating 20 preferably only covers a part of the outer surface of the braided network tube 10 to reduce the influence of the film coating 20 on the flexibility of the stent. If the flexibility of the intervention stent is good, it is also easy to pass through curved or tortuous blood vessels, and can also better fit the blood vessel wall, reducing the risk of thrombosis.

[0043] Next, refer to Figure 2 and Figure 3 , and a further description will be made on the combination mode of the film coating 20 and the braided network tube 10.

[0044] The present invention does not adopt suturing nor double-layer film coating. Instead, the two axial ends of the film coating 20 are respectively connected to a plurality of connecting membrane pieces 30 arranged in the lumen of the braided network tube 100 to fix the position of the film coating 20 on the braided network tube 10. More specifically, the proximal end of the film coating 20 is connected to a plurality of connecting membrane pieces 30 sequentially arranged in the circumferential direction of the braided network tube 10, and the distal end of the film coating 20 is also connected to another plurality of connecting membrane pieces 30 sequentially arranged in the circumferential direction of the braided network tube 10. All the connecting membrane pieces 300 are arranged in the lumen of the braided network tube 10, that is, the connecting membrane pieces 300 are attached to the inner surface of the braided network tube 100 without affecting the appearance of the stent. When assembling the film coating 20, the connecting membrane pieces 30 and the film coating 20 can be directly connected through the mesh 102, and the connecting membrane pieces 30 are kept flat, so that the edges of the connecting membrane pieces 30 are completely attached to the external film coating 20, thereby fixing both ends of the film coating 20 on the braided network tube 10. Preferably, the connecting membrane pieces 30 and the film coating 20 are connected by hot melting, which can avoid the deformation of the stent caused by the film coating 20, reduce the risk of stent deformation, make the reliability and stability of the stent better, and the performance is more excellent.

[0045] The connecting membrane piece 30 is actually a small membrane piece, and its size is much smaller than that of the film coating 20, which will not significantly increase the thickness of the stent and can ensure the flexibility of the stent. Moreover, each connecting membrane piece 30 only covers the braided wires 101 between two adjacent intersection points 103 and does not cover the intersection points 103 to avoid the influence of the intersection points 103 on the connecting membrane piece 30. Therefore, the connecting membrane piece 30 only covers the braided wires 101 between the intersection points 103. Because the two braided wires 101 forming the intersection point 103 will move, if the connecting membrane piece 30 covers the intersection point 103, it is easily affected by the two braided wires 101, and then it is not firm and easily falls off.

[0046] In addition, the braided wire 101 covered with the connecting diaphragm 30 is the braided wire 101 at a specific position. Specifically, the braided wire 101 covered with the connecting diaphragm 30 presses on another braided wire 101 at the corresponding intersection point 103, so that the other braided wire 101 pressed by the braided wire 101 covered with the connecting diaphragm 30 can block the connecting diaphragm 30 during the axial stretching of the interventional stent. This enables the connecting diaphragm 30 to move only on the braided wire 101 between two adjacent intersection points 103. In this way, a large displacement of the axial ends of the film covering 20 relative to the braided network tube 10 can be avoided, thus better fixing the position of the film covering 20 on the braided network tube 10. It can also prevent the film covering 20 from gathering and wrinkling towards the midline direction due to the expansion and contraction of the braided network tube 10, thereby avoiding excessive wrinkling of the film covering 20 and causing thrombosis. It also facilitates the operator to determine the position of the film covering 20, and then accurately release the film covering 20 at the aneurysm position to achieve immediate occlusion, improving the surgical efficiency.

[0047] It should be understood that when the interventional stent is axially stretched, the connecting diaphragm 30 has a tendency to slide towards the midline direction of the braided network tube 10 (the midline can be understood as the symmetry line perpendicular to the axis). At this time, the connecting diaphragm 30 will be blocked by the underlying braided wire 101 and cannot further displace. Therefore, it can be ensured that the external film covering 20 does not undergo obvious displacement during axial stretching, and the relative position between the film covering 20 and the braided network tube 10 does not change significantly. On the contrary, if the braided wire 101 covered with the connecting diaphragm 30 is pressed under another intersecting braided wire 101, and during the axial stretching process, when the connecting diaphragm 30 slides towards the midline direction of the braided network tube 100, the connecting diaphragm 30 may slide out from between the two intersecting braided wires 101, resulting in a large displacement. Therefore, the braided wire 101 covering the connecting diaphragm 30 is preferably pressed on another intersecting braided wire 101. Then, during axial stretching, the other underlying braided wire 101 resists the connecting diaphragm 30 and prevents the connecting diaphragm 30 from slipping out between the two braided wires 101, thereby improving the effectiveness of fixing the film covering 20.

[0048] Furthermore, during the stretching process, the braided network tube 10 elongates axially, and the connecting diaphragm 30 can only displace relative to the braided network tube 10 towards the midline direction. Thus, usually, it is only necessary to block the connecting diaphragm 30 in the direction of its axial sliding towards the midline, or rather, the other braided wire 101 pressed by the braided wire 101 covered with the connecting diaphragm 30 only needs to block the connecting diaphragm 30 in one direction to prevent the connecting diaphragm 30 from slipping out between the two braided wires 101.

[0049] More specifically, as Figure 2As shown, the braided wire 101 covered with the connecting diaphragm 30 is defined as the upper layer wire 101a. That is, when observing from the inside to the outside of the braided network tube 10, the braided wire 101 covered with the connecting diaphragm 30 is the upper layer wire 101a, and the wire pressed under the upper layer wire 101a is the lower layer wire 101b. Further, during the axial stretching process, even if the connecting diaphragm 30 slips towards the midline direction, the lower layer wire 101b can block the connecting diaphragm 30 to prevent the connecting diaphragm 30 from slipping out between the two braided wires 101. However, it should be understood that the braided wire 101 covered with the connecting diaphragm 30 is the upper layer wire 101a at the current intersection point 103, but is the lower layer wire 101b at another intersection point 101. Therefore, the upper layer wire 101a covering the connecting diaphragm 30 only refers to the intersection point 103 where the connecting diaphragm 30 needs to be limited.

[0050] Therefore, when the braided wire 101 covered with the connecting diaphragm 30 is the upper layer wire 101a at the corresponding intersection point 103, a large displacement of the axial ends of the covering film 20 relative to the braided network tube 10 can be avoided. In addition, if a developing structure 131 (see Figure 3 ) is provided at the positions of the two ends of the braided network tube 10 corresponding to the covering film 20, at this time, if the covering film 20 does not undergo a large displacement, it can also ensure that the two end edges of the covering film 20 are exactly positioned at the developing structure 131, which is convenient for the operator to determine the position of the covering film 20, and then accurately release the covering film 20 at the aneurysm neck opening, providing convenience for immediately blocking the aneurysm.

[0051] Furthermore, each connecting diaphragm 30 is not fixed (i.e., movable) to the braided wire 101 covering it. This can further reduce the influence of the connecting diaphragm 30 and the covering film 20 on the braided wire 101, and can also avoid more problems such as wrinkles and ruptures of the covering film 20.

[0052] Since the film coating 20 generally has little or no elasticity and cannot expand and contract together with the braided network tube 10, if wrinkles are formed in the film coating 20 during installation, the risk of rupture and the like of the film coating 20 during the expansion and contraction of the braided network tube 10 can be reduced, thereby improving the effectiveness of the film coating 20. For this reason, the film coating 20 is preferably sleeved on at least a part of the tube section of the braided network tube 10 in a wrinkled manner, that is, the length of the film coating 20 installed on the braided network tube 10 is less than the length of the film coating 20 when it is not installed. Thus, when the braided network tube 10 is in the natural state of not being stretched and not being contracted, after the film coating 20 is connected to the braided network tube 10 at both axial ends along the braided network tube 10, the film coating 20 is in a wrinkled state. It should be noted that when the interventional stent is in the folded and contracted state, the film coating 20 has no wrinkles in the length direction along the axis of the stent, but has wrinkles in the circumferential direction (i.e., the circumferential direction) of the stent. When the interventional stent is in the natural unfolded state, the film coating 20 has no wrinkles in the circumferential direction and has wrinkles in the length direction; the proportion of the wrinkles formed by the film coating 20 is the shortening rate of the interventional stent, and the shortening rate can be 10% to 50%.

[0053] The thickness of the connecting membrane 30 does not exceed the thickness of the film coating 20. The material of the connecting membrane 30 is the same as or different from the material of the film coating 20. When the material of the connecting membrane 30 is the same as the material of the film coating 20, the bonding strength is more excellent when the connecting membrane 30 and the film coating 20 are heat-melted, and while ensuring the heat-melt strength, the effectiveness of fixing the film coating 20 can be improved. In addition, after adding the connecting membrane 30, there is no need to increase the biological evaluation test, which is convenient to use. The connecting membrane 30 can have various shapes, including but not limited to the illustrated rectangle, as long as the connecting membrane 30 can be connected to the external film coating 20 to ensure the connection strength.

[0054] Preferably, the connecting membrane 30 is a rectangle, which is convenient for processing and also convenient for heat melting. The size of the connecting membrane 30 can be set according to the size of the grid 102, and the width of the connecting membrane 30 generally does not exceed the length of the braided wire 101 between two adjacent intersection points 103. For example, when the connecting membrane 30 is a rectangle, the length of the connecting membrane 30 is 0.2 mm to 5.0 mm, and the width is 0.2 mm to 5.0 mm.

[0055] The grid 102 is generally diamond-shaped, and each grid 102 is surrounded by four braided wires 101. The connecting membrane 30 can be covered on any one of the braided wires 101 of the grid 102. The same connecting membrane 30 can cover one or more braided wires 101. Preferably, only one braided wire 101 is covered. The connecting membranes 30 do not overlap and are all arranged independently of each other. However, in any case, each braided wire 101 covered with the connecting membrane 30 is pressed on the corresponding other braided wire 101 at the corresponding intersection point 103.

[0056] A plurality of connecting diaphragms 30 connected to any one end of the film covering 20 are sequentially distributed along the circumferential direction of the braided net tube 10 and are spaced apart from each other in the circumferential direction. The plurality of connecting diaphragms 30 connected to any one end of the film covering 20 are distributed uniformly or non-uniformly along the circumferential direction of the braided net tube 10, preferably uniformly distributed, so that the film covering 20 is stressed evenly and is not likely to have more wrinkles. There is no special requirement for the number of connecting diaphragms 30 connected to any one end of the film covering 20. On the premise of meeting the connection strength, the number of connecting diaphragms 30 is minimized to avoid increasing the thickness of the stent. Optionally, 4 connecting diaphragms 30 are connected to any one end of the film covering 20.

[0057] A plurality of connecting diaphragms 30 connected to any one end of the film covering 20 are sequentially arranged at intervals of N meshes 102 in the circumferential direction of the braided net tube 10, where N is a natural number of zero or greater than zero. That is, the connecting diaphragms 30 can be arranged at intervals of one or more meshes 102, or the connecting diaphragms 30 can be arranged without spacing the meshes 102. Not spacing the meshes 102 means that a connecting diaphragm 30 is arranged on each mesh 102.

[0058] As Figure 1 and Figure 2 As shown, in this embodiment, a plurality of connecting diaphragms 30 connected to any one end of the film covering 20 are sequentially arranged at intervals of one mesh 102 in the circumferential direction of the braided net tube 10. All the connecting diaphragms 30 cover the inner side of the braided wire 101 and are heat-melted with the external film covering 20 at high temperature. If a connecting diaphragm 30 is arranged at intervals of one mesh 102, while ensuring the connection strength of the film covering 20, the thickness of the stent can be in an optimal state.

[0059] A plurality of connecting diaphragms 30 connected to any one end of the film covering 20 are sequentially distributed in the circumferential direction of the braided net tube 10. These connecting diaphragms 30 can be aligned or staggered in the axial direction of the braided net tube 10. Axial alignment means that a plurality of connecting diaphragms 30 are arranged on the same circumference. At this time, a plurality of connecting diaphragms 30 can be arranged at the same position of a plurality of meshes 102 in the circumferential direction. Axial staggering means that a plurality of connecting diaphragms 30 are arranged on different circumferences, so that a plurality of connecting diaphragms 30 are arranged at different positions of a plurality of meshes 102 in the circumferential direction. Preferably, a plurality of connecting diaphragms 30 connected to the same end of the film covering 20 are axially aligned, which can avoid the risk of the film covering 20 warping due to uneven ends and reduce the thrombus risk.

[0060] As Figure 2As shown, in one embodiment, the connecting diaphragm 30 has an avoidance area 31 and a fixing area 32. The fixing area 32 is located on the periphery of the avoidance area 31, so that the connecting diaphragm 30 contacts and fits with the covered braided wire 101 through the avoidance area 31. However, the avoidance area 31 is not fixed to the braided wire 101, that is, there is no hot melting near the braided wire 101 to avoid affecting the sliding of the braided wire 101. After setting the avoidance area 31, the range where no hot melting is required near the braided wire 101 can be more accurately controlled, without affecting the sliding of the braided wire 101, and the influence on the braided tube 10 is minimized as much as possible. The fixing area 32 is used for hot melting with the film 20 to ensure the connection strength. The sizes and shapes of the avoidance area 31 and the fixing area 32 can be set according to actual needs and should not be limited to those shown in the drawings. The connecting diaphragm 30 can be centered or not centered on the braided wire 101.

[0061] In this embodiment, the connecting diaphragm 30 is rectangular, and such a diaphragm will not significantly increase the thickness of the stent. Preferably, the length of the avoidance area 31 is 1 / 4 to 1 / 3 of the total length of the connecting diaphragm 30, and the width of the avoidance area 31 is equal to the width of the fixing area 32.

[0062] However, in addition to connecting multiple connecting diaphragms 30 at both axial ends of the film 20, multiple connecting diaphragms 30 can be further connected at the target positions (including but not limited to the middle position) between the proximal end and the distal end of the film 20 to better fix the film 20.

[0063] Preferably, the film 20 is only sleeved on a part of the tube segments of the braided tube 10. Specifically, the braided tube 10 includes multiple tube segments. As Figure 1 shown, in this embodiment, the multiple tube segments are a distal bare segment 12, a film-covered segment 13, and a proximal bare segment 14 that are axially connected in sequence from the distal end to the proximal end. Further, a distal bell mouth segment 11 and a proximal bell mouth segment 15 can also be included. The film 20 is only sleeved on the film-covered segment 13, and except for the film-covered segment 13 being covered with the film 20, other tube segments are not covered with the film.

[0064] The diameter of the distal bell mouth segment 11 is larger than the diameter of the distal bare segment 12, the diameter of the proximal bell mouth segment 15 is larger than the diameter of the proximal bare segment 14, and the diameters of the distal bare segment 12 and the proximal bare segment 14 are not less than the diameter of the film-covered segment 13. The diameter of the film-covered segment 13 should be understood as the diameter after the film-covered segment 13 is sleeved with the film 20.

[0065] Both the distal bell mouth section 11 and the proximal bell mouth section 15 are outward-expanded bell mouths, which can play a better anchoring role after the interventional stent is opened. The membrane 20 will also restrain the membrane section 13 to a certain extent, causing the membrane section 13 to contract inward after being restrained by the membrane 20. Therefore, a distal bare section 12 is provided between the membrane section 13 and the distal bell mouth section 11, and a proximal bare section 14 is provided between the membrane section 13 and the proximal bell mouth section 15, which helps the distal and proximal ends of the interventional stent to adhere to the wall after release and prevent endoleakage.

[0066] The diameter of the distal bell mouth section 11 and the diameter of the proximal bell mouth section 15 can be the same or different. Preferably, the diameter of the distal bell mouth section 11 is 1.2 to 4 times the diameter of the distal bare section 12. Preferably, the diameter of the proximal bell mouth section 15 is 1.2 to 4 times the diameter of the proximal bare section 14. Preferably, the diameter of the distal bare section 12 and the diameter of the proximal bare section 14 are 1 to 1.5 times the diameter of the membrane section 13.

[0067] On the premise of ensuring sufficient anchoring force, the lengths of the distal bell mouth section 11 and the proximal bell mouth section 15 should be as short as possible. The distal bare section 12 should also be as short as possible. Then, after the interventional stent is released from the delivery system, it is beneficial for the operator to determine the distal position of the membrane 20 and achieve immediate occlusion of the aneurysm. The proximal bare section 14 should be long enough to facilitate the recovery and repositioning of the interventional stent. Specifically, after the membrane section 13 is released and the proximal bare section 14 has not yet detached from the delivery system, at this time, contrast agent can be injected to observe whether the membrane section 13 has occluded the aneurysm. If not, the interventional stent can be retrieved, adjusted in position and then released. The length of the proximal bare section 14 cannot be too long either. If it is too long, after the interventional stent is completely released, the proximal bare section 14 may block the branch vessels.

[0068] Preferably, the length of the distal bell mouth section 11 is 1.0 mm to 4.0 mm, and the length of the proximal bell mouth section 15 is 1.0 mm to 4.0 mm. Preferably, the length of the distal bare section 12 is 0 to 4.0 mm, and the length of the proximal bare section 14 is 2.0 mm to 5.0 mm. The length of the membrane section 13 is set according to the size of the aneurysm neck. Preferably, the length of the membrane section 13 is 4.0 mm to 30 mm, and this length enables the interventional stent to be applicable to most aneurysms.

[0069] Continue to refer to Figure 1, a developer spring 111 can be provided on the distal bell mouth section 11, and a developer sleeve 151 can be provided on the proximal bell mouth section 15. Thus, the distal end of the interventional stent can be positioned by the developer spring 111 on the distal bell mouth section 11, and the proximal end of the interventional stent can be positioned by the developer sleeve 151 on the proximal bell mouth section 15. Preferably, a plurality of developer springs 111 are circumferentially provided on the distal bell mouth section 110. Generally, 3 to 4 developer springs 111 are provided. Preferably, a plurality of developer sleeves 151 are circumferentially provided on the proximal bell mouth section 15, such as at least 3 to 4 developer sleeves 151. Here, the developer sleeve 151 on the proximal bell mouth section 15 can not only perform developer positioning, but also restrain the wire heads of the braided wires 101 to prevent the wire heads of the proximal braided wires from being exposed or forming tips, thereby reducing the damage to blood vessels.

[0070] Such as Figure 3 As shown, in this embodiment, developer structures 131 for positioning the covering film 20 are provided at both the proximal and distal ends of the covering film section 13. A plurality of developer structures 131 can be provided at any one end of the covering film stent section 130, such as 3 to 4 developer structures 131. The plurality of developer structures 131 at each end are provided evenly or unevenly along the circumference of the braided network tube 10. The developer structure 131 needs to be fixed at the end edge of the covering film 20, and at least part of the developer structure 131 can be covered by the covering film 20, and preferably all of it can be covered by the covering film 20, which can better determine the position of the covering film 20.

[0071] It should also be understood that the proximal end of the covering film section 13 is the distal end of the proximal bare section 14, and the distal end of the covering film section 13 is the proximal end of the distal bare section 12. Equivalently, developer structures 131 are provided at the distal end of the proximal bare section 14 and the proximal end of the distal bare section 12. The developer structure 131 can be a developer spring 111 or other structural forms. For the developer spring 111, it should be understood that it is made of a developer wire wound around the braided wire 101, and the developer wire can be further adhesively fixed to the braided wire 101.

[0072] However, it should be recognized that there can be various developer methods, including but not limited to the developer spring 111 and the developer sleeve 151 exemplified above.

[0073] Returning to the reference Figure 1 , there is no situation where the wire heads are exposed or there are tips at the proximal and distal ends of the braided network tube 10. The braided wires 101 at the proximal and distal ends both form closed loops to avoid damage to blood vessels caused by both ends of the braided network tube 10. The number of braided wires in this application is not limited. Common numbers of braided wires are 8, 12, 16, 24, 32, 48 or 64.

[0074] The present invention will be further illustrated by the following exemplary embodiments. However, these exemplary embodiments are merely illustrative and are intended to enable those skilled in the art to understand the present invention, rather than to limit the scope of protection of the present invention.

[0075]

Embodiment 1

[0076] In this embodiment, the number of braided filaments is 16. The covering film 20 is made of expanded polytetrafluoroethylene (ePTFE) material. The material of the connecting diaphragm 30 is the same as that of the covering film 20. Any one end of the covering film 20 is heat-melted with a plurality of axially aligned connecting diaphragms 30. And, in the circumferential direction of the braided network tube 10, a connecting diaphragm 30 is arranged at every other grid 102. Each connecting diaphragm 30 only covers one braided filament 101. The braided filament 101 covering the connecting diaphragm 30 is the upper-layer filament 101a at the corresponding intersection point 103. Then, local heat melting is carried out to make the edge of the connecting diaphragm 30 completely fused with the external covering film 20 until the boundary of the connecting diaphragm 30 is no longer visible, which not only ensures the heat-melting strength but also does not affect the appearance. Finally, an interventional stent with 4 connecting diaphragms 30 connected at each of the proximal and distal ends is obtained.

[0077]

Embodiment 2

[0078] The difference between the interventional stent provided in Embodiment 2 and Embodiment 1 is that a plurality of connecting diaphragms 30 connected to any one end of the covering film 20 are arranged at intervals of multiple grids 102 or without intervals of grids 102 in the circumferential direction of the braided network tube 10. And the number of the intervals of grids 102 can be the same or different. For example, it can be spaced by 1 grid 102, spaced by 2 grids 102, spaced by 3 grids 103, etc. However, it should be recognized that all the braided filaments 101 covering the connecting diaphragm 30 are the upper-layer filaments 101a at the corresponding intersection points 103.

[0079]

Embodiment 3

[0080] The difference between the interventional stent provided in Embodiment 3 and Embodiment 1 is that the connecting diaphragm 30 covers multiple braided filaments 101 at the same time.

[0081]

Embodiment 4

[0082] The difference between the interventional stent provided in Embodiment 4 and Embodiment 1 is that a plurality of connecting diaphragms 30 are covered on one braided filament 101.

[0083]

Embodiment 5

[0084] The difference between the interventional stent provided in Embodiment 5 and Embodiment 1 is that any one end of the covering film 20 is heat-melted with a plurality of axially staggered connecting diaphragms 30. If the plurality of connecting diaphragms 30 connected to the same end of the covering film 20 are axially staggered, they can be partially staggered or completely staggered, and various arrangement forms can exist, such as "zigzag" and "wavy", etc. In this regard, the present application is not limited.

[0085]

Example VI

[0086] The difference between the interventional stent provided in Example VI and Example I lies in that the materials of the film 20 and the connecting diaphragm 30 are different. For example, the connecting diaphragm 30 is made of ePTFE material, and the film 20 is made of other polymer materials such as polyester (PET), polyurethane (TPU), or polylactic acid (PLA).

[0087]

Example VII

[0088] The difference between the interventional stent provided in Example VII and Example I lies in that in addition to arranging the connecting diaphragms 30 at both axial ends of the film 20, a plurality of connecting diaphragms 30 are also heat-melted and connected at an intermediate position between the proximal end and the distal end of the film 20. At this time, it is ensured that all the connecting diaphragms 30 are arranged in the lumen of the braided network tube 10. In addition, a radiopaque structure 131 can be further arranged at the intermediate position of the film section 13 corresponding to the film 20.

[0089] In addition, based on the same inventive concept, the embodiments of the present invention also provide a film covering method for preparing the interventional stent provided in any one of the above preferred embodiments. The film covering method includes:

[0090] Providing a braided network tube 10;

[0091] Sheathing a film 20 on at least a part of the tube section of the braided network tube 10, preferably, the film 20 forms folds;

[0092] Connecting the proximal end and the distal end of the film 20 to a plurality of connecting diaphragms 30 that are circumferentially distributed and arranged in the lumen of the braided network tube 10 respectively. Preferably, the film 20 is heat-melted and connected to the connecting diaphragms 30;

[0093] Making each connecting diaphragm 30 cover the braided wire 101 between two adjacent crossing points 103, and making the braided wire 101 covered with the connecting diaphragm 30 press on another braided wire 101 at the corresponding crossing point 103, so that the other braided wire 101 pressed by the braided wire 101 covered with the connecting diaphragm 30 can block the connecting diaphragm 30 during the axial stretching process of the interventional stent.

[0094] However, the setting manner of the film 20 on the braided network tube 10 is not limited. For example, the film 20 is directly electrospun on the braided network tube 10, or a sheet-shaped film raw material is first prepared and then wound around the braided network tube 10 to obtain the film 20, or a tubular film raw material is first prepared and then sleeved on the braided network tube 10 to obtain the film 20, or other methods.

[0095] Furthermore, the film covering method further includes: not fixing each connecting diaphragm 30 to the braided wire 101 covering the connecting diaphragm 20, so that each connecting diaphragm 30 can only move on the braided wire 101 between two adjacent crossing points 103 it covers. Further, another braided wire 101 pressed by the braided wire 101 covered with the connecting diaphragm 30 blocks the connecting diaphragm 30 only in one direction.

[0096] In summary, compared with the prior art, the interventional stent provided by the present invention has the following advantages:

[0097] (1) Instead of using sutures for stitching or double-layer film covering, a single film covering is fixed on the braided network tube through multiple small diaphragms, and all small diaphragms are only arranged in the lumen of the braided network tube. In this way, the combination of the film covering and the braided network tube is realized. This method can avoid increasing the thickness of the stent to the greatest extent, does not affect the appearance of the stent, and can also reduce the influence of the film covering on the stent, ensuring the flexibility of the stent. Therefore, the defects of the existing film covering technology are overcome, providing conditions for the film-covered stent to enter a small delivery system and reach smaller blood vessels at a farther end.

[0098] (2) Further utilizing the self-structure of the braided network tube, the braided wire covering the small diaphragm is pressed on another braided wire intersecting with it. Even when axially stretched, the small diaphragm can be blocked by the pressed braided wire, avoiding large displacement of the small diaphragm. Furthermore, both ends of the film covering can only move within a relatively small area, preferably fixing the relative position of the film covering on the braided network tube.

[0099] (3) The method of hot-melting the external film covering of the small diaphragm can adapt to the elongation and shortening rate of the braided network tube exceeding 100%, does not affect the movement of the braided wire, and will not cause deformation of the stent due to the film covering. The risk of stent deformation is reduced, the reliability and stability are better, and the performance is superior.

[0100] (4) Compared with the traditional film covering method, the film covering method provided in this application is simpler, easier to operate mechanically, facilitating the simplification of the manufacturing process of the film-covered stent and improving production efficiency.

[0101] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the technical field of the present invention according to the above disclosure shall fall within the protection scope of the technical solution of the present invention.

Claims

1. An interventional stent, characterized in that, it includes a braided network tube, a film covering, and a plurality of connecting diaphragms. The braided network tube is braided by a plurality of braided wires. The plurality of braided wires intersect with each other to form meshes and intersection points. All the connecting diaphragms are arranged in the lumen of the braided network tube; the film covering is sleeved on at least part of the tube section of the braided network tube. The two axial ends of the film covering are respectively connected to a plurality of the connecting diaphragms. The plurality of connecting diaphragms connected to any one end of the film covering are circumferentially distributed on the braided network tube; each connecting diaphragm covers the braided wires between two adjacent intersection points. The braided wires covered with the connecting diaphragm press on another braided wire at the corresponding intersection point, so that the another braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm during the axial stretching process of the interventional stent.

2. The interventional stent according to claim 1, characterized in that, each connecting diaphragm is not fixed to the braided wire covering it. Each connecting diaphragm only moves on the braided wires between two adjacent intersection points it covers, and the another braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm in one direction.

3. The interventional stent according to claim 1 or 2, characterized in that, the film covering is sleeved on at least part of the tube section of the braided network tube in a wrinkled manner.

4. The interventional stent according to claim 1 or 2, characterized in that, the connecting diaphragm has an avoidance area and a fixing area. The fixing area is located on the periphery of the avoidance area. The connecting diaphragm is attached to the covered braided wire through the avoidance area, and the connecting diaphragm is thermally fused to the film covering through the fixing area.

5. The interventional stent according to claim 4, characterized in that, the connecting diaphragm is rectangular.

6. The interventional stent according to claim 5, characterized in that, the length of the avoidance area is 1 / 4 to 1 / 3 of the total length of the connecting diaphragm, and the width of the avoidance area is equal to the width of the fixing area.

7. The interventional stent according to claim 5, characterized in that, the length of the connecting diaphragm is 0.2 mm to 5.0 mm, and the width of the connecting diaphragm is 0.2 mm to 5.0 mm.

8. The interventional stent according to claim 1 or 2, characterized in that, the material of the film covering is the same as the material of the connecting diaphragm.

9. The interventional stent according to claim 1 or 2, characterized in that, the interventional stent further has at least one of the following features: the plurality of connecting diaphragms connected to any one end of the film covering are sequentially spaced N meshes apart in the circumferential direction of the braided network tube, where N is zero or a natural number greater than zero; the plurality of connecting diaphragms connected to any one end of the film covering are sequentially distributed in the circumferential direction of the braided network tube, and the plurality of connecting diaphragms are aligned or staggered in the axial direction of the braided network tube; The same connecting diaphragm covers one or more of the braided wires, and each braided wire covered with the connecting diaphragm presses on another braided wire at the corresponding intersection point.

10. The interventional stent according to claim 1 or 2, characterized in that the braided network tube has a plurality of tube segments, and the plurality of tube segments are a distal bare segment, a film-covered segment, and a proximal bare segment that are axially connected in sequence from the distal end to the proximal end. The film is sleeved on the film-covered segment and does not cover the distal bare segment and the proximal bare segment. The proximal and distal ends of the film-covered segment are provided with imaging structures for positioning the film.

11. A film-covering method for preparing an interventional stent, characterized in that it includes: providing a braided network tube, which is woven by a plurality of braided wires, and the plurality of braided wires intersect with each other to form a grid and intersection points; sleeving a film on at least part of the tube segments of the braided network tube; connecting the axial two ends of the film to a plurality of connecting diaphragms respectively, all the connecting diaphragms are arranged in the lumen of the braided network tube, and the plurality of connecting diaphragms connected to any one end of the film are distributed in the circumferential direction of the braided network tube; making each connecting diaphragm cover the braided wire between two adjacent intersection points, and making the braided wire covered with the connecting diaphragm press on another braided wire at the corresponding intersection point, so that the other braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm during the axial stretching process of the interventional stent.

12. The film-covering method according to claim 11, characterized in that it further includes: making each connecting diaphragm not fixed to the braided wire covering the connecting diaphragm, so that each connecting diaphragm can only move on the braided wire between two adjacent intersection points it covers, and making the other braided wire pressed by the braided wire covered with the connecting diaphragm can block the connecting diaphragm in one direction.

Images