Covered stent

Abstract

The utility model provides a covered stent which comprises a stent main body, a membrane tube and a plurality of fixed membranes, the stent main body comprises a covered section for installing the membrane tube and a naked section exposed outside the membrane tube, the membrane tube covers the whole outer surface of the covered section, and all the fixed membranes are accommodated in an inner cavity of the stent main body. The two axial ends of the membrane tube are in hot melting connection with the corresponding fixing membranes respectively, the fixing membranes connected with any end of the membrane tube are distributed in the circumferential direction of the stent body, and the stent body is provided with a plurality of first developing structures distributed in the circumferential direction of the stent body at the two axial ends of the membrane tube respectively. Therefore, connection of the membrane tube and the stent main body is realized under the condition of not adopting a suture and a double-layer membrane, and meanwhile, an operator can conveniently determine the position of the membrane tube.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, and in particular to a coated stent which does not adopt suturing and double-layer coating. Background Art

[0002] Cardiovascular and cerebrovascular diseases are important diseases that affect human health, among which aneurysms are the most common and endanger human health at all times. Covered stents have become increasingly widely used stents due to their inherent advantage of being able to be blocked, especially in lesions such as the thoracic aorta, abdominal aorta, heart valves, and carotid arteries, to isolate aneurysms and guide blood to flow along normal blood vessels.

[0003] In the prior art, sutures are usually used to sew the coating and the stent together, which undoubtedly increases the thickness of the stent and the thread ends are easily exposed to the outside, affecting the appearance of the stent. There is also a double-layer coating, which is provided inside and outside the stent, so that the inner and outer double-layer coatings are wrapped and fixed to the stent. Compared with a single-layer coating, a double-layer coating is more likely to increase the thickness of the stent, making it more difficult for the stent to enter smaller blood vessels. In particular, the double-layer coating is easy to bind the stent and make the stent lose its flexibility.

[0004] Therefore, how to design a coated stent that can combine the coating and the stent without using sutures and double-layer coating is a problem that needs to be solved urgently.

[0005] It should be noted that the information disclosed in the background technology section of this application is only intended to deepen the understanding of the general background technology of this application, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Utility Model Content

[0006] The utility model aims to provide a coated stent, aiming to realize the combination of a membrane and a stent without using sutures and double-layer coating, and to facilitate doctors to determine the position of the membrane.

[0007] To achieve the above-mentioned purpose, the utility model provides a stent graft, comprising:

[0008] The support body includes a membrane-covered section for mounting the membrane tube and a bare section exposed outside the membrane tube;

[0009] a membrane tube covering the entire outer surface of the membrane-covered section; and

[0010] A plurality of fixed membranes, all of which are accommodated in the inner cavity of the stent body;

[0011] The axial ends of the film tube are respectively hot-melt connected to the corresponding multiple fixed film sheets, and the multiple fixed film sheets connected to any one end of the film tube are distributed in the circumferential direction of the bracket body. The bracket body is respectively provided with multiple first developing structures distributed along the circumferential direction of the bracket body at the axial ends of the film tube.

[0012] Optionally, the plurality of first developing structures are at least partially covered by the film tube.

[0013] Optionally, all the first developing structures at any end of the film tube are at least partially non-offsetly distributed around the axis of the stent body in the circumferential direction of the stent body.

[0014] Optionally, the bracket body is formed by cross-weaving a plurality of braided wires, the plurality of braided wires cross each other to form intersections, and a plurality of the first developing structures are arranged on the braided wires between adjacent intersections.

[0015] Optionally, the number of the first developing structures at any end of the film tube is 3 to 4.

[0016] Optionally, at least part of the first developing structure is a developing spring.

[0017] Optionally, the membrane tube is also hot-melt connected to another plurality of the fixed membrane sheets at a preset position between its two ends, and the plurality of the fixed membrane sheets connected to the preset position are distributed in the circumferential direction of the bracket body. The bracket body is provided with a plurality of second developing structures at positions corresponding to the preset position, and the plurality of the second developing structures are distributed along the circumferential direction of the bracket body.

[0018] Optionally, the stent body is formed by cross-weaving a plurality of braided wires, the plurality of braided wires cross each other to form grid holes and intersections, each fixed membrane covers the braided wires between adjacent intersections, and each fixed membrane is not fixed to the braided wires covering the fixed membrane.

[0019] Optionally, the braided wire covering the fixed membrane is pressed on another braided wire that crosses it, so that the other braided wire limits the fixed membrane during the axial stretching of the stent graft.

[0020] Optionally, there are multiple bare segments, which are sequentially a distal bell-mouth segment, a distal transition segment, a proximal transition segment and a proximal bell-mouth segment; the distal bell-mouth segment, the distal transition segment, the coated segment, the proximal transition segment and the proximal bell-mouth segment are sequentially arranged from the distal end to the proximal end in the axial direction of the stent body; the diameter of the distal bell-mouth segment and the diameter of the proximal bell-mouth segment are larger than the diameter of the distal transition segment, the diameter of the coated segment and the diameter of the proximal transition segment; wherein, a plurality of third developing structures are respectively provided on the distal bell-mouth segment and the proximal bell-mouth segment, and the plurality of third developing structures on the distal bell-mouth segment and the proximal bell-mouth are distributed circumferentially of the stent body.

[0021] Optionally, the film tube forms folds on the film covering section.

[0022] Compared with the prior art, the stent graft provided by the utility model has at least the following advantages:

[0023] In the above-mentioned coated stent, neither suture suturing nor double-layer coating is used. Instead, the axial ends of a single membrane tube are hot-melted and fixed to the stent body through a number of fixed membrane sheets, and all the fixed membrane sheets are only arranged in the inner cavity of the stent body. While fixing the relative positions of the membrane tube and the stent body, this method can avoid increasing the thickness of the coated stent to the greatest extent, so that the coated stent can be transported and enter smaller blood vessels without affecting the appearance of the coated stent. It can also reduce the influence of the membrane on the coated stent and ensure the flexibility of the coated stent. In addition, due to the use of single-layer coating and partial coating, the influence of the membrane on the stent body can be reduced, the flexibility of the coated stent and the effectiveness of the membrane tube can be ensured, and the thickness of the stent can be further controlled. On this basis, the membrane tube is positioned by a plurality of first developing structures arranged at the axial ends of the membrane tube of the stent body, so that the operator (such as medical staff) can quickly determine the position of the membrane tube during the operation to improve the accuracy of the surgical operation and improve the efficiency of the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Those skilled in the art will appreciate that the drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0025] Figure 1 This is a schematic diagram of the overall structure of the stent graft in the embodiment of the present application, wherein the stent body is a braided stent;

[0026] Figure 2 This is a schematic diagram of a local structure of a coated stent using a developing structure to locate the position of a membrane tube in an embodiment of the present application, wherein a vertical line i represents the proximal edge of the membrane tube, and the membrane tube is to the left of the proximal edge;

[0027] Figure 3It is a schematic diagram of the local structure of the stent graft in the embodiment of the present application when the film tube and the stent body are fixed by hot-melting a plurality of fixing film sheets;

[0028] Figure 4 This is a schematic diagram of the overall structure of the coated stent in an embodiment of the present application, wherein the stent body adopts a cut stent. DETAILED DESCRIPTION

[0029] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis required to be shown in each drawing is different, and sometimes different proportions are used. As used in this specification, the singular forms "one", "an" and "the" include plural objects, unless the content clearly indicates otherwise. As used in this specification, the term "or" is generally used in a sense that includes "and / or", unless the content clearly indicates otherwise.

[0030] It should be noted that, in this article, relational terms such as first, second, third, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present utility model. In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In the present invention, unless otherwise clearly specified and limited, the first feature "above" or "below" the second feature can include the first and second features directly contacting, and can also include the first and second features not directly contacting but contacting through another feature between them. Moreover, the first feature "above", "above" and "above" the second feature include the first feature directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0031] In response to at least one technical problem existing in existing coated stents, the utility model provides a coated stent that can achieve the combination of a membrane tube (i.e., a coating) and a stent body without using sutures and double-layer coatings, while also making it convenient for the operator to determine the position of the membrane tube, thereby improving the accuracy of surgical operations and improving surgical efficiency.

[0032] The "diameter" mentioned in the following embodiments refers to the "outer diameter", "axial" refers to the longitudinal axis direction of the coated stent, "circumferential" refers to the direction around the longitudinal axis of the coated stent, "proximal" refers to the end of the coated stent close to the surgical operator (such as a doctor) when the coated stent is delivered, and "distal" refers to the end of the coated stent away from the surgical operator when the coated stent is delivered.

[0033] The following description is given with reference to the accompanying drawings.

[0034] like Figure 1 and Figure 4 As shown, the coated stent provided in the embodiment of the present application includes a stent body 10 and a film tube 20. Figures 1 to 3 In the exemplary embodiment described, the stent body 10 is a braided stent, which is formed by a plurality of braided wires 110 interlaced and braided with each other. Figure 4 As shown, the stent body 10 adopts a cut stent. Regardless of whether it is a cut stent or a braided stent, the stent body 10 has a grid hole 120 and a cross point 130. Further, the stent body 10 includes a coated section 11 for installing the membrane tube 20 and a bare section exposed outside the membrane tube 20, and the bare section will be further described in the following content. The membrane tube 20 is a coating, which is only coated on the entire outer surface of the coating section 11 to achieve a single-layer coating and a partial coating, reduce the influence of the membrane tube 20 on the stent body 10, ensure the flexibility of the coated stent and the effectiveness of the membrane tube 20, and better control the thickness of the stent.

[0035] like Figure 2 and Figure 3 As shown, the stent graft further includes a plurality of fixed membrane sheets 30, all of which are accommodated in the inner cavity of the stent body 10, that is, the fixed membrane sheets 30 are attached to the inner surface of the stent body 10, which does not affect the appearance of the stent graft, thereby ensuring the aesthetics of the stent graft. Figure 1 and Figure 4 As shown, the two axial ends (i.e., the proximal end and the distal end) of the membrane tube 20 are respectively hot-melt connected to the corresponding multiple fixed membrane sheets 30, and the multiple fixed membrane sheets 30 connected to any one end of the membrane tube 20 are distributed in the circumferential direction of the bracket body 10, that is, the proximal end of the membrane tube 20 is hot-melt connected to the multiple fixed membrane sheets 30 distributed in the circumferential direction, and the distal end of the membrane tube 20 is also hot-melt connected to another multiple fixed membrane sheets 30 distributed in the circumferential direction.

[0036] During hot melting, the fixed film 30 and the film tube 20 can be directly hot-melted through the mesh holes 120, and the fixed film 30 is kept flat, so that the edge of the fixed film 30 is completely fused with the external film tube 20, and finally the axial ends of the film tube 20 are fixed on the stent body 10, so as to fix the position of the film tube 20 on the stent body 10. It should also be noted that the fixed film 30 is actually a small film, and its size is much smaller than the film tube 20, so it can avoid increasing the thickness of the stent graft to the greatest extent, making it easier for the stent graft to be transported and enter smaller blood vessels, while ensuring the flexibility of the stent graft.

[0037] The size of the small diaphragm is set according to the size of the grid hole 120, and is basically not larger than the size of one grid hole 120. The thickness of the small diaphragm does not exceed the thickness of the membrane tube 20, such as the same as the thickness of the membrane tube 20. The material of the membrane tube 20 and the material of the fixed diaphragm 30 are the same or different, preferably the same. When the material of the fixed diaphragm 30 is the same as that of the membrane tube 20, the bonding strength of the fixed diaphragm 30 and the membrane tube 20 is better when hot-melted, while ensuring the hot-melt strength, the effectiveness of the fixed membrane tube 20 is improved. After adding the fixed diaphragm 30, there is no need to add biological evaluation tests, which is convenient to use.

[0038] like Figure 2 As shown, in order to facilitate the operator to quickly determine the position of the membrane tube 20 during the operation, the stent body 10 is provided with a plurality of first developing structures 140 at both axial ends of the membrane tube 20. The plurality of first developing structures 140 of the stent body 10 at any end of the corresponding membrane tube 20 are distributed along the circumference of the stent body 11, such as uniformly or unevenly distributed along the circumference. Preferably, the number of the first developing structures 140 of the stent body 10 at any end of the corresponding membrane tube 20 is 3 to 4, and the developing effect is good. In this way, the development of the coated section 11 can be achieved. The number of the first developing structures 140 is at least 3, which can form a plane in space to determine whether the coated stent has been opened in space, and the opening condition of the coated section 11 can also be judged. If the first developing structures 140 are 4, the developing property is better, but if there are more than 4, it will occupy too much space during transportation, increase the push resistance, and affect the flexibility. Moreover, after the stent is released, too many first developing structures 140 may also cause thrombosis.

[0039] In practice, the axial and circumferential positions of the multiple first developing structures 140 on the bracket body 10 are determined by the membrane tube 20, and the multiple first developing structures 140 can be directly set on the coated segment 11, and / or, the multiple first developing structures 140 are directly set on the bare segment adjacent to the coated segment 11, as long as the first developing structures 140 can locate the edge positions of the axial ends of the membrane tube 20.

[0040] Preferably, at least part of the plurality of first developing structures 140 is covered by the film tube 20, that is, at least part of each first developing structure 140 can enter the coverage of the film tube 30, and more preferably, each first developing structure 140 as a whole enters the coverage of the film tube 20, so that the positioning effect is better. Figure 2 As shown, the label i represents the proximal edge of the film tube 20, and the film tube 20 is to the left of the proximal edge, wherein all the first developing structures 140 arranged corresponding to the proximal edge i are completely covered by the film tube 20, that is, all the first developing structures 140 are directly arranged on the coating section 11 and covered by the film tube 20.

[0041] The first developing structure 16 can be made of platinum tungsten or other known materials that can be developed under X-ray irradiation. The structure of the first developing structure 140 is not limited, including but not limited to the developing spring shown in the figure, but any other structure that can be developed, such as a developing section, a developing ring, a developing sleeve, a developing coating, etc. Figure 2 In the illustrated example, the first developing structure 140 is a developing spring, which is formed by a developable metal wire wound around the braiding wire 110 and fixed to the braiding wire 110 .

[0042] In an optional embodiment, a plurality of first developing structures 140 are arranged on the braided wire 110 between adjacent intersections 130, and are not arranged on the intersections 130. For example, in this embodiment, the first developing structure 140 uses a developing spring, and each developing spring is wound and fixed on the braided wire 110 between adjacent intersections 130. In this way, it is convenient to process, manufacture and install the first developing structure 140, the developing effect is also good, and the impact on the bracket body 10 is small, especially considering the impact on the braided bracket. However, as long as the intersection 130 is not restricted and the activity of the bracket body 10 is not affected, the situation of setting the first developing structure 140 on the intersection 130 is not excluded.

[0043] All the first developing structures 140 of the stent body 10 at any end of the membrane tube 20 are at least partially non-displacedly distributed (i.e. aligned) around the axis of the stent body 10 in the circumferential direction of the stent body 10. "Displaced distribution" means that the first developing structures 140 connected to the same end are arranged at different positions in the axial direction of the stent body 10, which can also be understood as not being on the same circumference; "non-displaced distribution" means that they are arranged at the same position in the axial direction of the stent body 10, which can also be understood as being on the same circumference. In an optional embodiment, all the first developing structures 140 of the stent body 10 at any end of the membrane tube 20 are all non-displacedly distributed around the axis of the stent body 10 in the circumferential direction of the stent body 10. In another optional embodiment, part of the first developing structures 140 of the stent body 10 at any end of the membrane tube 20 are staggeredly distributed around the axis of the stent body 10 in the circumferential direction of the stent body 10, and the remaining part is non-displacedly distributed.

[0044] Generally, in the circumferential direction of the support body 10, the first developing structure 140 is arranged between two adjacent fixed film sheets 30, avoiding the fixed film sheets 30. It is preferred to arrange the fixed film sheets 30 and the first developing structure 140 in different grid holes 120 to facilitate hot-melting the fixed film tube 20 and the fixed film sheets 30. For example, Figure 2 The method shown.

[0045] Furthermore, the preset position of the membrane tube 20 between the two axial ends thereof is also connected to multiple other fixed membrane sheets 30 by heat melting, and the multiple fixed membrane sheets 30 connected to the preset position are distributed in the circumferential direction of the stent body 10, so as to better fix the membrane tube 20. At the same time, the stent body 10 is also provided with multiple second developing structures (not shown) at the position corresponding to the preset position, and the multiple second developing structures are distributed in the circumferential direction of the stent body 10, so as to realize the display of the preset position, so as to facilitate the operator to determine the position of the preset part. The preset position includes but is not limited to the middle position, but any position between the proximal end and the distal end.

[0046] The second developing structure may be arranged in a manner similar to the first developing structure 140, and the above content may be referred to for details. For example, all the second developing structures are at least partially non-displacedly distributed around the axis of the support body 10 in the circumferential direction of the support body 10, and the number of the second developing structures is 3 to 4, or other relevant contents. The principle of the arrangement of the second developing structure is not to restrict the intersection 130 and not to affect the movement of the support body 10.

[0047] Reference Figure 1 In one embodiment, the number of the bare segments is multiple, and the multiple bare segments are the distal flared segment 12, the distal transition segment 13, the proximal transition segment 14 and the proximal flared segment 15 in sequence, and the distal flared segment 12, the distal transition segment 13, the coating segment 11, the proximal transition segment 14 and the proximal flared segment 15 are arranged in sequence from the distal end to the proximal end in the axial direction of the stent body 10. The diameter of the distal flared segment 12 and the diameter of the proximal flared segment 15 are greater than the diameter of the distal transition segment 13, the diameter of the coating segment 11 and the diameter of the proximal transition segment 14. The distal flared segment 12, the distal transition segment 13, the proximal transition segment 14 and the proximal flared segment 15 are not covered by the membrane tube 20. However, the distal transition segment 13 is not a necessary configuration. In some cases, the stent body 10 may not include the distal transition segment 13, and in other cases, the stent body 10 includes the distal transition segment 13. The following is an exemplary description of including the distal transition segment 13.

[0048] The diameter of the distal bell-mouth section 12 decreases from the distal end to the proximal end, forming a bell-mouth, while the diameter of the proximal bell-mouth section 15 increases from the distal end to the proximal end, also forming a bell-mouth. In this way, the distal bell-mouth section 12 and the proximal bell-mouth section 15 can play a better anchoring role after the stent is opened, thereby improving the anchoring performance of the stent and making it less likely to shift.

[0049] Since the membrane tube 20 will restrain the coated section 11 to a certain extent, the proximal transition section 14 transitions the coated section 11 and the proximal flared section 15, so that the proximal end of the coated stent can be well attached to the wall after release to prevent internal leakage. Preferably, the distal transition section 13 transitions the coated section 11 and the distal flared section 12, so that the distal end of the coated stent can be well attached to the wall after release to further prevent internal leakage.

[0050] On the basis of ensuring anchoring force and wall adhesion, in order to achieve the recyclability of the stent graft, the present embodiment uses the proximal transition section 14 to achieve the purpose of recyclability and repositioning of the stent graft, and at the same time, it can also avoid blocking the branch blood vessels after the stent graft is completely released. Preferably, the length of the proximal transition section 14 is 2mm to 5mm, which makes the proximal transition section 14 neither too long nor too short. When the proximal transition section 14 is not too short, it is convenient to use the proximal transition section 14 to recycle the stent graft after the coating section 11 and the membrane tube 20 are completely released, and then release the stent graft after readjusting the position, so as to ensure the effectiveness and accuracy of isolating blood vessels and blood flow. Specifically, after the coating section 11 and the membrane tube 20 are completely released, the membrane tube 20 needs to adhere to the wall, and the proximal transition section 14 has not been released from the delivery system. At this time, contrast agent can be injected to observe whether the membrane tube 20 has blocked the aneurysm. If not, the stent graft can be reclaimed and released after adjusting the position. At the same time, the proximal transition section 14 cannot be too long to avoid blocking the branch blood vessels after the stent graft is completely released, thereby ensuring smooth blood flow in the branch blood vessels.

[0051] The length of the coated section 11 can be set according to the width of the aneurysm neck, so that the coated stent can be used to isolate most aneurysms and expand its application range. Therefore, the length of the coated stent section 11 is set to 4mm to 30mm, which can cover the width of the aneurysm neck of most aneurysms.

[0052] Furthermore, when the stent graft is provided with a distal transition section 13, the distal transition section 13 cannot be too long. Preferably, the length of the distal transition section 13 does not exceed 4 mm to ensure the positioning performance of the distal end of the graft, which is beneficial for doctors to determine the position of the distal end of the graft, and then quickly and accurately block the aneurysm. It can be understood that when a developing structure is provided on the distal flared section 12 and the distal end of the membrane tube 20 to position the stent graft, the stent graft will be axially stretched during transportation, and the stent graft will shrink during release. If the distal transition section 13 is short enough, the distance change between the developing structure on the distal flared section 12 and the first developing structure 140 during transportation and after release will be small enough, which is beneficial for doctors to determine the distal position of the membrane tube 20. Therefore, the distal transition section 13 should be short enough, or even no distal transition section 13 is provided.

[0053] Under the condition that the stent graft has sufficient anchoring force, the length of the distal flared section 12 and the length of the proximal flared section 15 should also be shortened as much as possible. Preferably, the length of the distal flared section 12 and the length of the proximal flared section 15 are 1 mm to 4 mm to reduce the length of the entire stent graft and reduce the difficulty of delivery. The length of the distal flared section 11 and the length of the proximal flared section 15 can be the same or different.

[0054] The diameters of the distal flare section 12 and the proximal flare section 15 may be the same or different, and there is no limitation on this. The diameter of the distal flare section 12 is preferably 1.2 to 4 times the diameter of the distal transition section 13, and correspondingly, the diameter of the proximal flare section 15 is preferably 1.2 to 4 times the diameter of the proximal transition section 14. This allows the stent graft to be better anchored in the blood vessel after release, reducing its risk of displacement. The diameter of the distal transition section 13 and the diameter of the proximal transition section 14 may be the same or different. The diameter of the distal transition section 13 and the diameter of the proximal transition section 14 are preferably 1 to 1.5 times the diameter of the coated section 11, which allows the distal and proximal ends of the coated stent to be better attached to the wall after release, and the anti-internal leakage effect is better. The diameter of the coated section 11 should be understood as the diameter of the coated section 11 after the film tube 20 is sheathed.

[0055] Continue to refer to Figure 1 In one embodiment, a plurality of third developing structures 150 are respectively provided on the distal bell-mouth section 12 and the proximal bell-mouth section 15, and all the third developing structures 150 on the distal bell-mouth section 12 and the proximal bell-mouth section 15 are distributed in the circumferential direction of the stent body 10. The position of the coated stent can be further located by the third developing structure 150, thereby improving the positioning performance. In an optional embodiment, the third developing structure 150 on the distal bell-mouth section 12 can adopt a developing spring, and the third developing structure 150 on the proximal bell-mouth section 15 can adopt a developing sleeve. The developing sleeve on the proximal bell-mouth section 15 can not only develop, but also connect the wire head of the braided wire 110 of the proximal bell-mouth section 15 to avoid the proximal wire head being exposed or forming a pointed end.

[0056] However, the developing spring and the developing sleeve are merely examples for implementing the developing structure described in the embodiments of the present application and do not constitute a limitation of the present application. Those skilled in the art should be able to understand that any developing structure described in the embodiments of the present application may also be replaced by other structural forms, and any developing structure is made of common developing materials.

[0057] The present application will further illustrate the configuration of the fixed diaphragm 30 through the following examples, but these examples are only illustrative and are intended to enable those skilled in the art to understand the present invention rather than to limit the protection scope of the present invention.

[0058] In one embodiment, each fixed diaphragm 30 only covers the braided wire 110 between two adjacent intersections 130, and does not cover the intersection 130. If the fixed diaphragm 30 covers the intersection 130, it is easily affected by the deformation of the intersection 130, and thus is not firm and easy to fall off. In addition, the fixed diaphragm 30 is not fixed to the braided wire 110 covering the fixed diaphragm 30, so that the fixed diaphragm 30 can slide relative to the fixed diaphragm 30 it covers, so as not to affect the activity of the braided wire 110, prevent the deformation of the stent, and avoid more wrinkles, ruptures and other problems in the membrane tube 20. Preferably, the braided wire 110 covering the fixed diaphragm 30 is pressed on another braided wire 110 that crosses it, so that the other braided wire 110 limits the fixed diaphragm 30 during the axial stretching process of the coated stent, so that the axial ends of the membrane tube 20 will not produce a large displacement. Therefore, the braided wire 110 covering the fixed diaphragm 30 is preferably a braided wire 110 at a specific position.

[0059] In more detail, when the stent graft is axially stretched, the fixed diaphragm 30 tends to slide toward the centerline direction of the stent body 10 (the centerline can be understood as the symmetry line perpendicular to the longitudinal axis), and at this time, the fixed diaphragm 30 will be blocked by the braided wire 110 pressed underneath and cannot be further displaced, thereby preventing the membrane tube 20 from being significantly displaced when the stent graft is stretched, and the position of the membrane tube 20 can be better fixed, so that the relative position of the membrane tube 20 and the stent body 10 does not change significantly. On the contrary, if the braided wire 110 covering the fixed diaphragm 30 is pressed underneath by another braided wire 110 interwoven with it, during the axial stretching of the stent graft, the fixed diaphragm 30 slides toward the centerline direction of the stent body 10, and the fixed diaphragm 30 may slide out from between the two intersecting braided wires 110, causing a large displacement. Therefore, preferably, the braided wire 110 covering the fixed membrane 30 is pressed on another braided wire 110 crossing it, so that when the coated stent is axially stretched, the other braided wire 110 that is pressed can resist the fixed membrane 30 and prevent the fixed membrane 30 from falling out from between the two braided wires 110.

[0060] For ease of understanding, the braided wire 110 covering the fixed diaphragm 30 is defined as the upper wire 111, that is, when observing from the inside to the outside of the stent body 10, the braided wire 110 covering the fixed diaphragm 30 is the upper wire 111, and the lower wire 112 is pressed underneath by the upper wire 111. Furthermore, during the stretching process, the fixed diaphragm 30 slides toward the center line until the fixed diaphragm 30 is blocked by the lower wire 112 and no longer moves. However, the braided wire 110 covering the fixed diaphragm 30 is the upper wire 111 at the current intersection 130, but is the lower wire 112 at another intersection 110. Therefore, the upper wire 111 covering the fixed diaphragm 30 is only for the intersection 130 where the fixed diaphragm 30 needs to be limited. For details, please refer to Figure 3 .

[0061] When the braided wire 110 covering the fixed membrane 30 is the upper wire 111 at the corresponding intersection 130, the two axial ends of the membrane tube 20 can be prevented from being displaced greatly relative to the stent body 10, which can better fix the position of the membrane tube 20 on the stent body 10, prevent the membrane tube 20 from gathering and wrinkling in the midline direction due to the expansion and contraction of the stent body 10, and thus prevent the membrane tube 20 from wrinkling too much and causing thrombosis. In addition, when the membrane tube 20 does not undergo a large displacement, it can ensure that the two end edges of the membrane tube 20 are aligned with the first developing structure 140, which is convenient for doctors to determine the position of the membrane tube 20, so as to facilitate the immediate occlusion of the aneurysm.

[0062] The fixed film 30 can have various shapes, including but not limited to the rectangular shape shown in the figure, as long as the fixed film 30 can be connected to the external film tube 20 by heat melting to ensure the connection strength. Usually, the fixed film 30 is rectangular, which is convenient for processing and heat melting. When the fixed film 30 is rectangular, preferably, the length of the fixed film 30 is 0.2 mm to 5.0 mm, and the width is 0.2 mm to 5.0 mm.

[0063] The mesh holes 120 are mostly rhombus-shaped, and each mesh hole 120 is surrounded by four braided wires 110. The fixed diaphragm 30 can be covered on any braided wire 110 of the mesh hole 120. The same fixed diaphragm 30 can cover one or more braided wires 110, preferably, only one braided wire 110. The fixed diaphragms 30 and the fixed diaphragms 30 do not overlap, and are all independently arranged. However, in any case, each braided wire 110 covering the fixed diaphragm 30 is preferably pressed on the corresponding other braided wire 110 at the corresponding intersection 130.

[0064] The multiple fixed membranes 30 connected to any end of the membrane tube 20 are distributed in sequence along the circumference of the stent body 10, and are spaced apart from each other in the circumferential direction. The multiple fixed membranes 30 connected to any end of the membrane tube 20 are evenly or unevenly distributed along the circumference of the stent body 10, preferably evenly distributed, so that the membrane tube 20 is evenly stressed and less prone to more wrinkles. There is no special requirement for the number of fixed membranes 30 connected to any end of the membrane tube 20. On the premise of meeting the connection strength, the number of fixed membranes 30 is minimized to avoid increasing the thickness of the stent. In this embodiment, four fixed membranes 30 are connected to any end of the membrane tube 20.

[0065] For any end of the membrane tube 20, multiple fixed membranes 30 are arranged in sequence at intervals of N grid holes 120 in the circumferential direction of the bracket body 10, and the value of N is zero or a natural number greater than zero. That is, the fixed membrane 30 can be arranged at intervals of one or more grid holes 120, and the fixed membrane 30 can also be arranged at each grid hole 120 (that is, not arranged at intervals).

[0066] like Figure 3 As shown, as an example, a plurality of fixed membrane sheets 30 connected to any end of the membrane tube 20 are arranged one mesh hole 120 apart in the circumferential direction of the stent body 10, and all the fixed membrane sheets 30 cover the inner side of the braided wire 110 and are heat-fused with the outer membrane tube 20 at a high temperature. If a fixed membrane sheet 30 is arranged every mesh hole 120, it is possible to better avoid increasing the thickness of the stent while ensuring the connection strength of the membrane tube 20.

[0067] The multiple fixed membranes 30 connected to any end of the membrane tube 20 can be aligned or staggered in the axial direction of the stent body 10, that is, in the circumferential direction of the stent body 10, the multiple fixed membranes 30 can be staggered or aligned around the axis of the stent body 10. Preferably, the multiple fixed membranes 30 connected to the same end of the membrane tube 20 are not staggered around the axis of the stent body 10 in the circumferential direction of the stent body 10, thereby avoiding the risk of the membrane tube 20 warping due to uneven ends and reducing the risk of thrombosis.

[0068] like Figure 3 As shown, in this embodiment, the fixed diaphragm 30 is provided with an avoidance zone 31 and a hot melt zone 32, and the hot melt zone 32 is located at the periphery of the avoidance zone 31, so that the fixed diaphragm 30 is in contact with the covered braided wire 110 through the avoidance zone 31, but the avoidance zone 31 is not fixed to the braided wire 110, that is, the braided wire 110 is not hot-melted near it to avoid affecting the elasticity and flexibility of the stent body 10. After setting the avoidance zone 31, the range near the braided wire 110 that does not require hot melting can also be more accurately controlled, without affecting the sliding of the braided wire 110, and minimizing the impact on the stent body 10. The hot melt zone 32 is used to hot-melt with the membrane tube 20 to ensure the connection strength. The size and shape of the avoidance zone 31 and the hot melt zone 32 can be set according to actual needs and should not be limited to those shown in the accompanying drawings. The fixed diaphragm 30 can be set centered or not centered on the braided wire 110.

[0069] The fixed diaphragm 30 is preferably rectangular so as not to significantly increase the thickness of the bracket. More preferably, the length of the avoidance zone 31 is 1 / 4 to 1 / 3 of the total length of the fixed diaphragm 30 , and the width of the avoidance zone 31 is equal to that of the hot melt zone 32 .

[0070] There is no limitation on the coating method of the membrane tube 20 on the support body 10. For example, the membrane tube 20 can be obtained by electrospinning directly on the support body 10, or a sheet-like membrane tube raw material is first prepared, and then the sheet-like membrane tube raw material is wound on the support body 10 to obtain the membrane tube 20, or a tubular membrane tube raw material is first prepared, and then the tubular membrane tube raw material is sleeved on the support body 10 to obtain the membrane tube 20.

[0071] The membrane tube 20 is a commonly used polymer material, including but not limited to self-expanded polytetrafluoroethylene (ePTFE), polyester (PET), polyurethane (TPU) and polylactic acid (PLA). The membrane tube 20 is usually inelastic or less elastic, and cannot expand and contract with the stent body 10. In order to further reduce the influence of the membrane tube 20 on the stent, preferably, the membrane tube 20 forms wrinkles on the coating section 11, that is, the length of the membrane tube 20 installed on the stent body 10 is less than the length of the membrane tube 20 when it is not installed. It can be understood that when the membrane tube 20 forms wrinkles on the coating section 11, it means that when the stent is compressed, the membrane tube 20 has no wrinkles in the length direction and wrinkles in the circumferential direction; and when the stent is in the natural state, the membrane tube 20 has no wrinkles in the circumferential direction and wrinkles in the length direction; the wrinkle ratio of the membrane tube 20 is the shortening rate of the stent, and the shortening rate is generally 10% to 50%.

[0072] The membrane tube 20 is wrinkled when installed, which can also reduce the risk of the membrane tube 20 breaking when the stent body 10 is stretched or contracted, thereby improving the effectiveness of the membrane tube 20. It should be understood that in the folded and contracted state, the membrane tube 20 has no wrinkles in the longitudinal direction along the axial direction of the stent body 10, but has wrinkles in the circumferential direction along the stent body 10. On the contrary, in the unfolded and expanded state, the membrane tube 20 has no wrinkles in the circumferential direction but has wrinkles in the longitudinal direction.

[0073] The stent body 10 is made of known materials, such as but not limited to one or a combination of multiple materials selected from cobalt-based alloys, stainless steel, nickel-titanium alloys, platinum alloys, iridium alloys, active ceramics and carbon, or a composite material selected from these materials.

[0074] The coated stent in the embodiment of the present invention can be self-expanding or unfolded with the help of external force, and has a folded and contracted state and an unfolded and expanded state, and can also switch between the folded and contracted state and the unfolded and expanded state. When the coated stent is delivered through a conveying system, it is in a folded and contracted state. In the folded and contracted state, the coated stent is axially stretched, so that its radial dimension becomes smaller, which is convenient for transportation. After the coated stent is released from the conveying system, it is in an unfolded and expanded state. It should also be noted that when the coated stent is not constrained by external force, it is also in an unfolded and expanded state. At this time, the unfolded and expanded state is a natural state.

[0075] Preferably, the braided wires 110 at the proximal and distal ends of the stent body 10 form closed loops, without exposed wire heads or sharp tips, to prevent the two ends of the stent body 10 from causing damage to the blood vessels. The present application does not limit the number of braided wires 110, including but not limited to 8, 12, 16, 24, 32, 48 or 64 heads.

[0076] Compared with the prior art, the stent graft provided by the utility model has at least the following advantages:

[0077] First, the use of single-layer coating and partial coating can reduce the influence of the coating on the stent body, ensure the flexibility of the coated stent and the effectiveness of the film, and also can avoid increasing the thickness of the stent.

[0078] Second, neither suturing nor double-layer coating is used. Instead, the film tube is hot-melt fixed to the stent body through multiple fixed film sheets, and all the fixed film sheets are only set in the inner cavity of the stent body, thereby realizing the connection between the film tube and the stent body. This method can avoid increasing the thickness of the stent to the greatest extent, and provides conditions for the coated stent to enter the small delivery system to reach the more distal small blood vessels without affecting the appearance of the stent. It can also reduce the impact of the film tube on the stent body and ensure the flexibility of the coated stent.

[0079] Third, the stent body is provided with a plurality of first developing structures at both axial ends of the membrane tube, so as to facilitate the doctor to determine the position of the membrane tube during the operation, and then release the membrane tube quickly and accurately, thereby improving the efficiency and accuracy of the operation.

[0080] Fourthly, the braided wire can be used to limit the fixed diaphragm to avoid large displacement of the fixed diaphragm, so that the two ends of the membrane tube can only move in a relatively small area, and the position of the membrane tube on the stent body can be better fixed.

[0081] Fifth, the coating method can adapt to the elongation and shortening rate of the stent body exceeding 100%, and will not affect the activity of the braided wire, and will not cause the stent to deform due to the film tube. The risk of stent deformation is reduced, the reliability and stability are better, and the performance is better.

[0082] In general, compared with the traditional coating method, the method of fixing the film tube by hot-melting the fixed film sheet is simpler and easier to mechanize, which is convenient for simplifying the manufacturing process of the coated stent and improving production efficiency.

[0083] The above description is only a description of the preferred embodiment of the utility model, and is not any limitation on the scope of the utility model. Any changes and modifications made by ordinary technicians in the field of the utility model based on the above disclosure are within the protection scope of the technical solution of the utility model.

Claims

1. A stent graft, characterized in that: include: The support body includes a membrane-covered section for mounting the membrane tube and a bare section exposed outside the membrane tube; A membrane tube covering the entire outer surface of the membrane-covered section; as well as, A plurality of fixed membranes, all of which are accommodated in the inner cavity of the stent body; The axial ends of the film tube are respectively hot-melt connected to the corresponding multiple fixed film sheets, and the multiple fixed film sheets connected to any one end of the film tube are distributed in the circumferential direction of the bracket body. The bracket body is respectively provided with multiple first developing structures distributed along the circumferential direction of the bracket body at the axial ends of the film tube.

2. The stent graft according to claim 1, characterized in that: At least part of the plurality of first developing structures is covered by the film tube.

3. The stent graft according to claim 1, characterized in that: All the first developing structures at any end of the film tube are at least partially non-staggeredly distributed around the axis of the stent body in the circumferential direction of the stent body.

4. The stent graft according to claim 1, characterized in that: The support body is formed by cross-weaving a plurality of braided wires, wherein the plurality of braided wires cross each other to form intersections, and a plurality of the first developing structures are arranged on the braided wires between adjacent intersections.

5. The stent graft according to claim 1, characterized in that: The number of the first developing structures at any end of the film tube is 3 to 4.

6. The stent graft according to claim 1, characterized in that: At least part of the first developing structure is a developing spring.

7. The stent graft according to claim 1, characterized in that: The membrane tube is also hot-melt connected to multiple other fixed membrane sheets at a preset position between its two ends. The multiple fixed membrane sheets connected to the preset position are distributed in the circumferential direction of the bracket body. The bracket body is provided with multiple second developing structures at positions corresponding to the preset position. The multiple second developing structures are distributed along the circumferential direction of the bracket body.

8. The stent graft according to claim 1, characterized in that: The stent body is formed by cross-weaving a plurality of braided wires, which cross each other to form grid holes and intersections, and each fixed membrane covers the braided wires between adjacent intersections, and each fixed membrane is not fixed to the braided wires covering the fixed membrane.

9. The stent graft according to claim 8, characterized in that: The braided wire covering the fixed membrane is pressed on another braided wire crossing with the braided wire, so that the other braided wire limits the fixed membrane during the axial stretching of the stent graft.

10. The stent graft according to claim 1, characterized in that: There are multiple bare segments, which are sequentially a distal bell-mouth segment, a distal transition segment, a proximal transition segment and a proximal bell-mouth segment. The distal bell-mouth segment, the distal transition segment, the coated segment, the proximal transition segment and the proximal bell-mouth segment are sequentially arranged from the distal end to the proximal end in the axial direction of the stent body. The diameter of the distal bell-mouth segment and the diameter of the proximal bell-mouth segment are larger than the diameter of the distal transition segment, the diameter of the coated segment and the diameter of the proximal transition segment. The distal bell-mouth segment and the proximal bell-mouth segment are respectively provided with multiple third developing structures, and the multiple third developing structures on the distal bell-mouth segment and the proximal bell-mouth are distributed in the circumferential direction of the stent body.

11. The stent graft according to claim 1, characterized in that: The film tube forms folds on the film covering section.

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