Dense mesh bracket

Abstract

A dense mesh stent, comprising a first interval section, a second interval section and a third interval section connected in an axial direction, the dense mesh stent comprising a plurality of first braided wires extending spirally in one direction and a plurality of second braided wires extending spirally in another direction, on an unfolded plane of the dense mesh stent cut in an axial direction, a plurality of first braided wires are parallel to each other, a plurality of second braided wires are parallel to each other, a plurality of second braided wires form a braiding unit, each first braided wire in the first interval section corresponds to a second braided wire and alternately presses each other, each first braided wire in the second interval section corresponds to a braiding unit and alternately presses each other, and each first braided wire in the third interval section corresponds to a second braided wire and alternately presses each other. When the dense mesh stent of the present invention is implanted in a curved blood vessel, it can well adapt to the shape of the blood vessel and reduce the pressure on the blood vessel by both ends of the dense mesh stent.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a dense mesh stent. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] Intracranial aneurysm is a dilatation disease of intracranial blood vessels formed in the local area of ​​cerebral arteries due to abnormal development or damage. The protruding wall of the intracranial aneurysm will continue to thin under the impact of blood flow until it ruptures and bleeds. The usual consequence is subarachnoid hemorrhage in patients, so it has a very high disability and mortality rate. The incidence of aneurysm rupture is rapid and there is no obvious sign, which seriously threatens the health of patients.

[0004] At present, the most ideal way to treat intracranial aneurysms is interventional treatment. The interventional treatment is carried out under the guidance and monitoring of imaging equipment throughout the whole process. It can accurately and directly reach the local lesion without major trauma. Therefore, it has the advantages of accuracy, safety, efficiency, wide indications and few complications. The cylindrical dense mesh stent made of woven metal wire is a commonly used medical device for interventional treatment. In order to improve the radial support capacity, the existing dense mesh stent generally uses alloy wires with strong mechanical properties. The most common metal wire materials are medical stainless steel, cobalt-chromium alloy, nickel-titanium alloy, etc. The weaving method is that the left-hand wire and the right-hand wire are cross-woven with each other, that is, the weaving method of "one thread pressed on one thread", which is collectively referred to as "one pressed on one" in this field. The advantages of the stent made by this weaving method are that it is easy to weave and the support capacity of the stent is uniform.

[0005] The diameter of intracranial blood vessels is generally thinner, and smaller stents are needed for thinner blood vessels. Intracranial aneurysms are generally caused by shear force generated by blood flow, so aneurysms often occur at the bends or bifurcations of cerebral arteries. However, the existing dense mesh stents have poor flexibility. When implanted into curved blood vessels, large stresses act on the inner wall of the blood vessels at both ends of the bent dense mesh stent, which may seriously damage the blood vessels. Summary of the invention

[0006] The purpose of the present invention is to at least solve the technical problem of poor flexibility of the existing dense mesh stent. This purpose is achieved through the following technical solutions:

[0007] An embodiment of the present application proposes a dense mesh stent, which includes a first interval segment, a second interval segment and a third interval segment connected along the axial direction. The dense mesh stent includes multiple first braided wires extending spirally in one direction and multiple second braided wires extending spirally in another direction. On an unfolded plane of the dense mesh stent cut along the axial direction, multiple first braided wires are parallel to each other, multiple second braided wires are parallel to each other, and multiple second braided wires form a braiding unit. Each first braided wire in the first interval segment corresponds to a second braided wire and they press each other alternately, each first braided wire in the second interval segment corresponds to a braiding unit and they press each other alternately, and each first braided wire in the third interval segment corresponds to a second braided wire and they press each other alternately.

[0008] In one embodiment, a coating is further provided in the second interval section, and the coating is respectively sandwiched between the first braided wires and the second braided wires.

[0009] In one embodiment, there are multiple coatings in the second interval segment, gaps are left between the multiple coatings, and the gaps between two adjacent coatings are filled with the first braided wires and the second braided wires.

[0010] In one embodiment, there is at least one transition section between the first interval segment and the second interval segment, and / or between the third interval segment and the second interval segment, each first braided wire in the transition section corresponds to multiple second braided wires and alternately presses each other, the number of second braided wires corresponding to each first braided wire in the transition section is less than the number of second braided wires in the braiding unit, and the number of second braided wires corresponding to each first braided wire in the transition section is greater than 1.

[0011] In one embodiment, a coating is further provided in the transition section, and the coating is sandwiched between the first braided wires and the second braided wires, respectively, and a gap is left between the coating in the transition section and the coating in the second interval section.

[0012] In one embodiment, the axial length of the second interval segment is greater than the maximum width of the tumor neck opening.

[0013] In one embodiment, at least a portion of the first braided wire and the second braided wire is a multi-strand wire.

[0014] In one embodiment, the multiple strands of wire include a core wire and multiple surrounding wires, the multiple surrounding wires surround the core wire, the circumferential surfaces of the multiple core wires abut against the circumferential surfaces of the surrounding wires and together surround to form a cavity, and the cavity is filled with drugs.

[0015] In one embodiment, at least a portion of the core wire and / or the surrounding wire is a polymer wire.

[0016] In one embodiment, at least a portion of the first braided wires and the second braided wires are polymer wires.

[0017] On the unfolded plane of the above-mentioned dense mesh stent cut along the axial direction, each first braided wire in the second interval segment corresponds to a braided unit (i.e., multiple second braided wires) and alternately press each other, so that the first braided wire has less restraint on the second braided wire, and the amount that two adjacent second braided wires can slide is relatively large. Therefore, the flexibility of the dense mesh stent in the second interval segment can be increased. When the dense mesh stent is implanted in a curved blood vessel, it can adapt well to the shape of the blood vessel and reduce the pressure on the blood vessel by both ends of the dense mesh stent. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0019] Figure 1 This is a schematic structural diagram of a dense mesh stent without a coating according to the first embodiment of the present invention;

[0020] Figure 2 It is a structural schematic diagram of a dense mesh support according to a first embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of the multi-strand wire in the second embodiment of the invention;

[0022] Figure 4 This is a schematic structural diagram of a dense mesh stent without a coating according to a third embodiment of the present invention;

[0023] Figure 5 Schematic diagram of the structure of a dense mesh support according to the third embodiment of the present invention. DETAILED DESCRIPTION

[0024] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0025] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an", and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain", and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof.

[0026] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0027] For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0029] It should be noted that, in the present application, the end closer to the operator during use is referred to as the "proximal end", and the end farther from the operator is referred to as the "distal end".

[0030] First embodiment

[0031] As shown in FIG. 1 , the present embodiment provides a dense mesh stent 10, comprising a plurality of first braided wires 111 (also referred to as right-hand wires) extending spirally in one direction and a plurality of second braided wires 115 (also referred to as left-hand wires) extending spirally in another direction, wherein the first braided wires 111 and the second braided wires 115 are interlaced with each other to form a diamond mesh. The sum of the number of the first braided wires 111 and the second braided wires 115 ranges from 24 to 96, and the first braided wires 111 and the second braided wires 115 are made of metal material, including metal wires with shape memory (cobalt-chromium alloy wires or nickel-titanium alloy wires) and metal wires with developability (such as platinum wires), wherein the number of the metal wires with developability ranges from 2 to 8.

[0032] In this embodiment, the first braided wire 111 and the second braided wire 115 are both single wires, and the wire diameter of the first braided wire 111 and the second braided wire 115 ranges from 0.01 mm to 0.05 mm. The PPI of the dense mesh stent 10 ranges from 230 to 300 (PPI is the weft density of the braid, i.e., the number of meshes within the axial length of a 1-inch stent), the optimal PPI ranges from 250 to 280, and the diameter of the dense mesh stent 10 ranges from 1.5 mm to 8 mm.

[0033] like Figure 1As shown, the dense mesh stent 10 includes a first interval section 117, a second interval section 118 and a third interval section 119 connected axially. On the unfolding plane of the dense mesh stent 10 cut along the axial direction, a plurality of first braided wires are parallel to each other, a plurality of second braided wires are parallel to each other, a plurality of second braided wires 115 form a braiding unit 113, and each first braided wire 111 in the first interval section 117 corresponds to a second braided wire 115 and alternately presses each other, so that the first braided wire 111 and the second braided wire 115 in the first interval section 117 are bound to each other, so that the first braided wire 111 and the second braided wire 115 in the first interval section 117 are not easy to diverge, thereby ensuring the complete braiding structure of the dense mesh stent 10 in the first interval section 117. Each first braided wire 111 in the second interval 118 corresponds to a braided unit 113 and alternately presses each other, so that the first braided wire 111 has less restraint on the second braided wire 115, and the amount of sliding of two adjacent second braided wires 115 is relatively large, so the flexibility of the dense mesh stent 10 in the second interval 118 can be increased. When the dense mesh stent 10 is implanted in a curved blood vessel, it can adapt well to the shape of the blood vessel and reduce the pressure on the blood vessel by both ends of the dense mesh stent 10. Each first braided wire 111 in the third interval 119 corresponds to a second braided wire 115 and alternately presses each other, which can also ensure the complete braiding structure of the dense mesh stent 10 in the first interval 117. The number of second braided wires 115 in the braided unit 113 can be 2, 3, 4 or more. In this embodiment, the number of second braided wires 115 in the braided unit 113 can be 4.

[0034] In another embodiment of the present invention, at least a portion of the first braided wire 111 and the second braided wire 115 is a polymer wire. For example, a portion or all of the first braided wire 111 and the second braided wire 115 are polymer wires, or a portion or all of the first braided wire 111 are polymer wires, or a portion or all of the second braided wire 115 are polymer wires. In this way, the dense mesh stent 10 includes polymer wires, thereby reducing the proportion of metal wires in the dense mesh stent 10, but the flexibility of the dense mesh stent 10 is increased.

[0035] like Figure 2 As shown, a coating 127 is further provided in the second interval section 118 , and the coating 127 is sandwiched between the first braided wires 111 and the second braided wires 115 .

[0036] In the prior art, a coated stent generally includes an inner membrane, an outer membrane, and a bare metal stent formed with a grid, wherein the inner membrane is fixed to the inner surface of the bare metal stent, and the outer membrane is fixed to the outer surface of the bare metal stent. The bare metal stent of the existing coated stent is subject to a large restraining effect of the inner membrane and the outer membrane, making the coated stent easily restrained by the inner membrane and the outer membrane during bending and deformation, resulting in poor flexibility of the coated stent, making it difficult to adapt to various complex and curved blood vessels, and there is a certain risk of the inner and outer membranes falling off under the scouring effect of blood flow. In addition, after the coated stent is implanted, since the surfaces of the inner and outer membranes are relatively smooth, it is difficult for endothelial cells to grow and crawl on the surfaces of the inner and outer membranes. During the endothelialization process of the stent, the outer surface of the stent is completely covered by endothelial cells, and then further grows to the inner surface of the stent. Since the inner and outer membranes are continuous membranes, the endothelial cells can only grow from the openings at both ends of the stent to the middle area of ​​the stent when crawling to the inner membrane, thereby completely covering the entire stent. However, during the endothelialization process, since the inner and outer membranes are not conducive to the crawling and growth of endothelial cells and the distance required to crawl is relatively long, it will cause the endothelial cells to grow and reproduce and difficult to reach the middle area of ​​the inner surface of the stent, and then the stent is not completely endothelialized, which can easily lead to the formation of thrombus in the stent.

[0037] In this embodiment, a coating 127 is provided in the second interval 118. When implanted, the second interval 118 corresponds to the tumor cavity. The coating 127 in the second interval 118 covers the tumor neck, which can prevent blood flow from impacting the tumor cavity and achieve a better treatment effect. Moreover, the coating 127 is sandwiched between the first braided wire 111 and the second braided wire 115, which can prevent the coating 127 from being impacted by blood flow and falling off. Even if blood enters the tumor cavity from the gap between the two adjacent coatings 127, the blood flow rate entering the tumor cavity will become very slow due to the blocking effect of the coating 127, the first braided wire 111 and the second braided wire 115, which will cause blood to thrombose in the tumor cavity, thereby achieving a better treatment effect. In addition, the first interval 117 and the third interval 119 are not provided with the coating 127, which can avoid the deterioration of flexibility caused by the provision of the coating 127.

[0038] In addition, in the present embodiment, there are multiple coatings 127 in the second interval segment 118, and the width of each coating 127 is adapted to the width of the weaving unit 113, so that the coating 127 can be clamped by the first weaving wire 111 and the second weaving wire 115, and gaps are left between the coatings 127, so that adjacent coatings 127 will not be bound to each other, thereby avoiding adjacent weaving units 113 from being bound to each other due to the connected coatings 127. Therefore, when the dense mesh stent 10 in the present embodiment is implanted in a curved blood vessel, the parts in the second interval segment 118 are less bound to each other and can adapt well to the shape of the blood vessel. In this embodiment, the two adjacent coatings 127 of the second interval segment 118 are separated by the first braided wire 111 and the second braided wire 115, so that a small gap is generated between the two adjacent coatings 127. The gap is equal to the larger wire diameter of the first braided wire 111 and the second braided wire 115, which can avoid the gap being too large to reduce the effect of isolating blood flow, and because there is a gap between the two adjacent coatings 127, it is beneficial for endothelial cells to crawl from the gap to the inner surface of the coating 127, which can accelerate endothelialization, so that the endothelial cells can cover the entire dense mesh stent 10, thereby physically isolating the wrong flow of blood; and because the gap between the two adjacent coatings 127 is filled with the first braided wire 111 and the second braided wire 115, the gap can be reduced, which can greatly slow down the flow rate of blood entering the tumor cavity, thereby reducing the impact on the tumor cavity wall.

[0039] In this embodiment, the axial length of the second interval segment 118 is greater than the maximum width of the tumor neck opening, so that the coating 127 in the second interval can cover the entire tumor neck opening, thereby achieving a better treatment effect.

[0040] The surface of the first braided wire 111 and the second braided wire 115 is provided with an anti-thrombotic coating (not shown in the figure). The material of the anti-thrombotic coating can be one or more of heparin, phosphorylcholine, paclitaxel and rapamycin, which can prevent the formation of thrombus on the surface of the dense mesh stent 10 after implantation, and can effectively reduce the irritation and inflammation of the patient after the dense mesh stent 10 is implanted.

[0041] In another embodiment of the present invention, the dense mesh stent 10 may not include the coating 127 , but only include the first braided wires 111 and the second braided wires 115 .

[0042] Second embodiment

[0043] like Figure 3As shown, the difference between this embodiment and the first embodiment is that at least one of the first braided wire and the second braided wire is a multi-strand wire 212. For example, a part or all of the first braided wire and the second braided wire are multi-strand wires 212, or a part or all of the first braided wire is multi-strand wire 212, or a part or all of the second braided wire is multi-strand wire 212. Compared with a single wire, the multi-strand wire 212 includes multiple parts (i.e., multiple single wires). When implanted in a curved blood vessel, each part of the multi-strand wire 212 can have a certain displacement relative to other parts, so that the dense mesh stent is easier to deform.

[0044] like Figure 3 As shown, the multi-strand wire 212 includes a core wire 214 and a plurality of surrounding wires 216, the plurality of surrounding wires 216 surround the core wire 214, the circumferential surfaces of the plurality of core wires 214 abut against the circumferential surfaces of the surrounding wires 216 and together surround to form a cavity 218, the cavity 218 is filled with drugs (such as the above-mentioned anti-thrombotic drugs), when the dense mesh stent is transported, the outer surface of the dense mesh stent and the microcatheter have sliding friction, and the drugs filled in the cavity 218 can prevent wear. At least a portion of the core wire 214 and / or the surrounding wire 216 is a polymer wire, which can further improve the flexibility of the dense mesh stent.

[0045] Third embodiment

[0046] like Figure 4 As shown, the difference between this embodiment and the second embodiment is that at least one transition section 321 is included between the first interval section 317 and the second interval section 318, and / or between the third interval section 319 and the second interval section 318, each first braided wire 311 in the transition section 321 corresponds to a plurality of second braided wires 315 and alternately presses each other, the number of second braided wires 315 corresponding to each first braided wire 311 in the transition section 321 is less than the number of second braided wires 315 in the braiding unit 313, and the number of second braided wires 315 corresponding to each first braided wire 311 in the transition section 321 is greater than 1, so that the flexibility of the transition section 321 is between the first interval section 317 and the second interval, thereby avoiding the flexibility of the first interval section 317 and the second interval section 318 from changing sharply, resulting in easy bending. In this embodiment, a transition section 321 is included between the first interval section 317 and the second interval section 318, and a transition section 321 is included between the third interval section 319 and the second interval section 318.

[0047] In other embodiments, a plurality of transition sections 321 are included between the first interval section 317 and the second interval section 318, or a plurality of transition sections 321 are included between the third interval section 319 and the second interval section 318, or a transition section 321 is included between one of the first interval section 317 and the third interval section 319 and the second interval section 318.

[0048] like Figure 5 As shown, a coating 327 is further provided in the transition section 321 , and the coating 327 is respectively sandwiched between the first braided wire 311 and the second braided wire 315 , and a gap is left between the coating 327 in the transition section 321 and the coating 327 in the second interval section 318 , so as to prevent the coating 327 from reducing the flexibility of the dense mesh bracket 30 .

[0049] The sum of the axial lengths of the transition section 321 and the second interval section 318 is greater than the maximum width of the tumor neck opening, so that the transition section 321 and the second interval section 318 can cover the tumor neck opening.

[0050] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A dense mesh bracket, characterized in that: The dense mesh stent comprises a first interval section, a second interval section and a third interval section connected in an axial direction, the dense mesh stent comprises a plurality of first braided wires extending spirally in one direction and a plurality of second braided wires extending spirally in another direction, on an unfolded plane of the dense mesh stent cut along the axial direction, a plurality of the first braided wires are parallel to each other, a plurality of the second braided wires are parallel to each other, a plurality of the second braided wires form a braiding unit, each of the first braided wires in the first interval section corresponds to a second braided wire and alternately presses each other, each of the first braided wires in the second interval section corresponds to a braiding unit and alternately presses each other, and each of the first braided wires in the third interval section corresponds to a second braided wire and alternately presses each other; A coating is also provided in the second interval section, and the coating is respectively sandwiched between the first braided wire and the second braided wire, and the width of the coating is adapted to the width of the braiding unit; There are multiple coatings in the second interval segment, the width of each coating is adapted to the width of the weaving unit, gaps are left between the multiple coatings, and the gaps between two adjacent coatings are filled with the first braiding wires and the second braiding wires.

2. The dense mesh bracket according to claim 1, characterized in that: There is at least one transition section between the first interval segment and the second interval segment, and / or between the third interval segment and the second interval segment, each of the first braided wires in the transition section corresponds to multiple second braided wires and alternately presses each other, the number of second braided wires corresponding to each of the first braided wires in the transition section is less than the number of second braided wires in the braiding unit, and the number of second braided wires corresponding to each of the first braided wires in the transition section is greater than 1.

3. The dense mesh bracket according to claim 2, characterized in that: A coating is also provided in the transition section. The coating is respectively sandwiched between the first braided wires and the second braided wires. A gap is left between the coating in the transition section and the coating in the second interval section.

4. The dense mesh support according to claim 1, characterized in that: The axial length of the second interval segment is greater than the maximum width of the tumor neck.

5. The dense mesh support according to claim 1, characterized in that: At least a portion of the first braided wire and the second braided wire is a multi-strand wire.

6. The dense mesh bracket according to claim 5, characterized in that: The multiple strands of wire include a core wire and multiple surrounding wires, the multiple surrounding wires surround the core wire, the circumferential surfaces of the multiple core wires abut against the circumferential surfaces of the surrounding wires and together surround to form a cavity, and the cavity is filled with medicine.

7. The dense mesh support according to claim 6, characterized in that: At least a portion of the core wire and / or the surrounding wire is a polymer wire.

8. The dense mesh support according to claim 1, characterized in that: At least a portion of the first braided wires and the second braided wires are polymer wires.

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