阅读说明：本技术 一种可降解的双层支架 (Degradable double-layer bracket ) 是由 贾晶 刘振全 吴重草 孙冰 于 2021-01-22 设计创作，主要内容包括：本发明提供一种可降解的双层支架,该双层支架是一种由大致圆筒形的龙骨支架、密网支架由外而内依次套接而成的双层结构,所述龙骨支架和密网支架为网状编织物、网状切割物或二者的组合,所述双层支架可全部降解或部分降解,其中,所述龙骨支架的丝径大于所述密网支架的丝径,所述龙骨支架的网孔尺寸大于所述密网支架的网孔尺寸。根据本发明,内层密网支架保证充分覆盖率的同时,外层龙骨支架与微导管壁的接触面积相对较小,使支架整体具有更小的推送阻力；相比单层结构的可降解支架,该双层支架在血管内具有更好的锚定性能以及更小的回缩率；在完成了血管内介入治疗后,支架能够发生部分或全部降解,从而减少因其长期留存在体内引发的慢性问题。(The invention provides a degradable double-layer bracket which is a double-layer structure formed by sequentially sleeving a roughly cylindrical keel bracket and a dense-mesh bracket from outside to inside, wherein the keel bracket and the dense-mesh bracket are net-shaped braided fabrics, net-shaped cutting objects or a combination of the net-shaped braided fabrics and the net-shaped cutting objects, the double-layer bracket can be completely degraded or partially degraded, the wire diameter of the keel bracket is larger than that of the dense-mesh bracket, and the mesh size of the keel bracket is larger than that of the dense-mesh bracket. According to the invention, the contact area between the outer-layer keel bracket and the wall of the micro-catheter is relatively small while the inner-layer dense-mesh bracket ensures sufficient coverage rate, so that the bracket has smaller push resistance as a whole; compared with a degradable stent with a single-layer structure, the double-layer stent has better anchoring performance and smaller retraction rate in a blood vessel; after completing the endovascular intervention, the stent can be partially or fully degraded, thereby reducing chronic problems caused by its long-term retention in the body.)

1. The degradable double-layer support is characterized in that the degradable double-layer support is a double-layer structure formed by sequentially sleeving a roughly cylindrical keel support and a dense net support from outside to inside, the keel support and the dense net support are net-shaped braided fabrics, net-shaped cutting objects or a combination of the net-shaped braided fabrics and the net-shaped cutting objects, the double-layer support can be completely degraded or partially degraded, the wire diameter of the keel support is larger than that of the dense net support, and the mesh size of the keel support is larger than that of the dense net support.

2. The degradable bi-layer scaffold according to claim 1, wherein the partial degradation is that only the dense mesh scaffold degrades and the keel scaffold does not degrade.

3. The degradable double layered stent of claim 1 wherein the keel stent and dense mesh stent are secured by laser welding, adhesion or mechanical attachment.

4. The degradable double-layered scaffold according to claim 1, wherein the diameter of the double-layered scaffold is 2-50 mm and the length thereof is 10-500 mm.

5. The degradable double-layer stent according to claim 1, wherein the length ratio of the dense-mesh stent to the keel stent is 1: 1-2.

6. The degradable double layered scaffold according to claim 1, wherein the keel scaffold has two ends protruding beyond the dense mesh scaffold and has a trumpet-like structure at the ends.

7. The degradable bilayer stent of claim 1, wherein the material of the keel stent is a degradable or non-degradable metal or alloy, or a natural degradable polymer material, or a synthetic degradable polymer material and its copolymer, wherein the degradable or non-degradable metal or alloy comprises: the natural degradable high polymer material comprises iron base, magnesium base, platinum tungsten, platinum iridium, nickel titanium or cobalt chromium alloy, and the natural degradable high polymer material comprises: collagen, gelatin, cellulose and chitin, wherein the synthetic degradable high molecular material and the copolymer thereof comprise: polylactide, polyglycolide, polycyanoacrylate, polycaprolactone, polyanhydride, polyorthoester, polyphosphazene, polyglycolic acid, polylactic acid, and poly epsilon-caprolactone.

8. The degradable double-layered scaffold according to claim 1, wherein the material of the dense-mesh scaffold is degradable metal or alloy, or natural degradable high molecular material, or synthetic degradable high molecular material and its copolymer, wherein the degradable metal or alloy comprises: the natural degradable high polymer material comprises the following components: collagen, gelatin, cellulose and chitin, wherein the synthetic degradable high molecular material and the copolymer thereof comprise: polylactide, polyglycolide, polycyanoacrylate, polycaprolactone, polyanhydride, polyorthoester, polyphosphazene, polyglycolic acid, polylactic acid, and poly epsilon-caprolactone.

9. The degradable double-layered scaffold according to claim 1, wherein the material of the keel scaffold is magnesium-based alloy and the material of the dense mesh scaffold is polylactic acid.

10. The degradable bilayer stent of claim 1, further comprising a visualization element or a visualization filament having a visualization function.

Technical Field

The invention relates to the field of medical equipment, in particular to a degradable double-layer stent.

Background

In the field of vascular interventional therapy, stent implantation is a common treatment means, and at present, the commonly used intravascular stents are mainly made of biologically inert metal or alloy, and are commonly made of stainless steel, nickel-titanium alloy and the like. The mechanical property of the metal stent is greatly different from that of a human blood vessel, and due to the non-degradable characteristic, the stent can be remained in a human body for a long time after the implantation operation, which brings a series of chronic problems such as blood vessel injury, hyperplasia and the like. And when the stent implantation part is attacked again and needs secondary treatment, the early stent implantation which is not taken out can greatly increase the complexity of the operation condition.

To solve these problems, an ideal intravascular stent should give sufficient mechanical support to a diseased vessel within a proper time (usually 3-6 months) after being implanted in a diseased site of a patient's blood vessel, and after completing a therapeutic action (for example, 6 months), the intravascular stent is gradually degraded and absorbed, thereby reducing damage to the blood vessel of a human body. At present, the degradable stent is widely concerned. Common degradable high polymer materials have the defect of low strength, and in order to achieve mechanical properties equivalent to those of metal stents, the high polymer stents need to have larger stent wall thickness, so that additional risks are introduced.

Disclosure of Invention

The invention aims to provide a degradable double-layer stent, thereby solving the problems of long-term safety of a metal stent in a human body and insufficient strength of a single-layer degradable high-molecular stent in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

the degradable double-layer support is a double-layer structure formed by sequentially sleeving a roughly cylindrical keel support and a dense-net support from outside to inside, wherein the keel support and the dense-net support are net-shaped braided fabrics, net-shaped cutting objects or a combination of the net-shaped braided fabrics and the net-shaped cutting objects, the double-layer support can be completely degraded or partially degraded, the wire diameter of the keel support is larger than that of the dense-net support, and the mesh size of the keel support is larger than that of the dense-net support.

It should be understood that the mesh-like woven fabric in the present invention means a mesh-like structure formed by weaving a metal, alloy or polymer wire-like material as a raw material, and the mesh-like cut product means a mesh-like structure formed by cutting a metal, alloy or polymer tubular material as a raw material.

According to the preferable scheme of the invention, the degradable scaffold can be only a dense-mesh scaffold, or both the keel scaffold and the dense-mesh scaffold can be degraded.

The keel support and the dense mesh support are fixed through laser welding, adhesion or mechanical connection.

Preferably. The outer diameter of the dense mesh support is equivalent to the inner diameter of the keel support.

Preferably, the diameter of the double-layer bracket is 2-50 mm, and the length of the double-layer bracket is 10-500 mm.

Preferably, the length ratio of the dense mesh support to the keel support is 1: 1-2.

The two ends of the keel bracket extend out of the dense mesh bracket and are provided with horn-shaped structures at the end parts. According to the invention, the trumpet-shaped structures at the two ends of the keel bracket can be formed by flaring after weaving or cutting is finished, or can be formed directly in the forming process, and the included angle of the openings of the trumpet-shaped structures relative to the central axis of the bracket is preferably 30-60 degrees, and most preferably 60 degrees.

The keel bracket is made of degradable or non-degradable metal or alloy, or natural degradable high polymer material, or synthetic degradable high polymer material and copolymer thereof, wherein the degradable or non-degradable metal or alloy comprises: the natural degradable high polymer material comprises iron base, magnesium base, platinum tungsten, platinum iridium, nickel titanium or cobalt chromium alloy, and the natural degradable high polymer material comprises: collagen, gelatin, cellulose and chitin, the synthetic degradable high molecular material and the copolymer thereof comprise: polylactide, polyglycolide, polycyanoacrylate, polycaprolactone, polyanhydride, polyorthoester, polyphosphazene, polyglycolic acid, polylactic acid, and poly epsilon-caprolactone.

The material of the dense-mesh scaffold is degradable metal or alloy, or natural degradable high polymer material, or synthetic degradable high polymer material and copolymer thereof, wherein the degradable metal or alloy comprises: the natural degradable high polymer material comprises the following components: collagen, gelatin, cellulose, chitin and the like, and the synthetic degradable high polymer material and the copolymer thereof comprise: polylactide, polyglycolide, polycyanoacrylate, polycaprolactone, polyanhydride, polyorthoester, polyphosphazene, polyglycolic acid, polylactic acid, and poly epsilon-caprolactone.

According to a particularly preferred scheme of the invention, the material of the keel bracket is magnesium-based alloy, and the material of the dense-mesh bracket is polylactic acid.

The double-layer bracket also comprises a developing element or a developing wire with a developing function.

According to the double-layer stent provided by the invention, the degradation time of the keel stent is preferably 1-2 years, and the degradation time of the dense-mesh stent is preferably 6 months-1 year.

According to one embodiment of the invention, in the practical application of the degradable double-layer stent, the dense-mesh stent is positioned at the neck of the aneurysm to ensure that the aneurysm is effectively occluded with the highest possible mesh density, and the keel stent has enough mechanical supporting force for the diseased blood vessel to ensure the normal blood flow. After a period of time, the tumor body is gradually reduced or even disappears due to the blood flow guiding effect of the double-layer stent, and the double-layer stent is completely or partially gradually degraded and absorbed after finishing the treatment effect, so that the damage to the blood vessel of the human body is reduced.

The invention mainly aims to provide a degradable double-layer stent which consists of an outer-layer keel stent and an inner-layer dense-mesh stent and can be used for interventional therapy of aneurysm. The contact area between the outer layer keel support and the wall of the micro-catheter is relatively small while the inner layer dense-mesh support ensures sufficient coverage rate, so that the support has smaller pushing resistance as a whole; compared with a degradable stent with a single-layer structure, the double-layer stent has better anchoring performance and smaller retraction rate in a blood vessel; after completing the endovascular intervention, the stent can be partially or fully degraded, thereby reducing chronic problems caused by its long-term retention in the body.

Compared with the prior art, the degradable double-layer bracket provided by the invention has the beneficial effects that:

1) when the scaffold is in a pushing configuration, the degradable double-layer scaffold is placed in a micro-catheter for conveying in a pressing and holding state, only the outer-layer keel scaffold is in contact with the catheter wall, and compared with the existing dense-mesh scaffold which is in direct contact with the micro-catheter, the scaffold is relatively small in contact area and has smaller friction resistance;

2) when the stent is positioned in a blood vessel, the radial supporting force for the blood vessel wall is provided by the keel stent, and the keel stent has higher strength and supporting force, and is not easy to collapse, retract and shift compared with a high-polymer dense-mesh stent;

3) after the degradable double-layer stent completes vascular interventional therapy, the stent can be partially or completely degraded, so that the risk of occluding branch vessels and the long-term safety problem are reduced;

4) compared with a single-layer degradable high polymer bracket, the strength of the degradable high polymer bracket is ensured by the design of a double-layer structure, and the advantage that the degradation speed of a degradable high polymer material is easy to regulate and control is kept;

5) the horn mouth-shaped structure formed by the keel bracket ensures that the double-layer bracket has better anchoring effect and supporting force.

In conclusion, the degradable double-layer stent provided by the invention has the advantages of improved safety, enhanced strength, adjustable degradation speed and reduced push resistance, and can be used for interventional therapy of aneurysms.

Drawings

FIG. 1 is a schematic structural view of a degradable double-layered scaffold provided according to a preferred embodiment of the present invention;

fig. 2 is a schematic structural view of a degradable double-layered stent provided according to another preferred embodiment of the present invention.

Detailed Description

The present invention will be further described with reference to the following specific examples. It should be understood that the following examples are illustrative only and are not intended to limit the scope of the present invention.

As shown in fig. 1, the degradable double-layered stent provided according to a preferred embodiment of the present invention is formed by sequentially sleeving a substantially cylindrical keel stent 1 and a dense mesh stent 2 from outside to inside, where the keel stent 1 and the dense mesh stent 2 may be both mesh-woven fabrics or both mesh-cut materials, or a combination thereof, where the filament diameter of the keel stent 1 is larger than that of the dense mesh stent 2, and the mesh size of the keel stent 1 is larger than that of the dense mesh stent 2. In other words, the outer layer keel support 1 is a sparse net structure with larger wire diameter and larger meshes, and the inner layer dense net support 2 is a dense net structure with smaller wire diameter and smaller meshes. The bilayer scaffold may be fully or partially degradable.

According to a preferred embodiment of the invention, in practical application, the degradable double-layer stent is released to the aneurysm of a patient blood vessel, the keel stent 1 enables the pushing resistance of the stent to be reduced during delivery, the dense-mesh stent 2 is positioned at the neck of the aneurysm so as to ensure effective occlusion of the aneurysm body with the highest mesh density possible, and the double-layer stent should have enough mechanical supporting force for the diseased blood vessel to ensure normal blood flow in a certain period (usually 3-6 months). After a period of time, the tumor body is gradually reduced or even disappears due to the blood flow guiding effect of the double-layer stent, and the whole or part of the double-layer stent is gradually degraded and absorbed after the treatment effect is completed, so that the damage to the blood vessel of the human body is reduced.

Preferably, the diameter of the double-layer bracket is 2-50 mm, and the length of the double-layer bracket is 10-500 mm.

Preferably, the wire diameter of the keel support 1 is at least 1% larger than that of the dense mesh support 2.

Preferably, the length ratio of the dense mesh stent 2 at the inner layer to the keel stent 1 at the outer layer is 1: 1-2, and most preferably, the length ratio is 1: 1.25.

According to the preferred embodiment, the keel support 1 has both ends protruding beyond the dense mesh support 2 and has a trumpet-like structure at the ends. Therefore, compared with the existing single-layer stent, the double-layer stent has better anchoring performance and smaller retraction rate in a blood vessel, the openings at the two ends of the keel stent 1 fixed with the dense mesh stent 2 are in a horn-shaped structure with the caliber larger than that of the middle section, the structure is more favorable for anchoring the stent in the blood vessel, has better supporting effect, and greatly reduces the possibility of serious consequences such as collapse, retraction, displacement and the like. According to the preferred embodiment, the openings of the trumpet-like structure are angled at 60 ° with respect to the central axis of the stent.

As shown in fig. 1, the degradable double-layered stent has a developing element 3 fixed therein, and according to the preferred embodiment, the developing elements 3 are four in total and are respectively fixed at any network nodes on the keel stent 1.

According to the present invention, the two ends of the keel support 1 are also preferably provided with a plurality of fixing parts, which are fixing parts formed by binding woven wires or cutting wires at the ends of the keel support, and can be welding points formed by welding, or connecting parts or kink structures formed by mechanical fixing, or glue points formed by bonding, and the shape of the fixing parts is not particularly limited.

It should be understood that the developing member 3 may be provided not only at the network node but also at the fixing portions of both ends of the keel support 1. Furthermore, considering that the developing elements 3 on the bracket are dispersedly arranged at the crossing points of the woven silk screen of the bracket or the fixing parts at two ends of the woven silk screen of the bracket, only the local positions of the bracket can be marked, when the bracket is degraded to a certain extent, the developing points or the developing rings cannot accurately position the position of the bracket, and possibly remain in a free state in the blood vessel to cause other adverse reactions; therefore, for a completely degradable stent, it is preferable to perform development labeling using a degradable development polymer material.

According to a preferred embodiment of the present invention, the outer layer of the keel support 1 of the degradable double-layered support is made of a biologically inert metal or alloy, such as cobalt-chromium alloy. Further, after the inner-layer dense mesh stent 2 is completely degraded, the keel stent 1 is continuously remained in the blood vessel; the mesh of the keel bracket 1 is large, and the blockage of branch blood vessels and the like can not be caused.

According to another preferred embodiment of the present invention, in the degradable double-layered scaffold, the outer keel scaffold 1 is made of degradable metal or alloy, such as iron-based alloy. Further, after the inner layer dense mesh support 2 is completely degraded, the keel support 1 is gradually degraded; this embodiment has better long term safety than the embodiment where the keel support is not degradable.

According to a preferred embodiment of the present invention, the raw material of the keel frame 1 may be degradable or non-degradable metal or alloy, including but not limited to iron-based, magnesium-based, platinum-tungsten, platinum-iridium, nickel titanium or cobalt-chromium alloy, or natural degradable polymer material such as collagen, gelatin, cellulose and chitin, or synthetic degradable polymer material such as polylactide, polyglycolide, polycyanoacrylate, polycaprolactone, polyanhydride, polyorthoester and/or polyphosphazene, or copolymer between the above polymers, such as: polyglycolic acid (PGA), polylactic acid (PLA), poly-e-caprolactone (PCL), and the like.

According to a preferred embodiment of the present invention, the material of the dense mesh scaffold 2 is degradable metal or alloy, including but not limited to iron-based, magnesium-based alloy, and may also be natural degradable high molecular material such as collagen, gelatin, cellulose and chitin, or synthetic degradable high molecular material such as polylactide, polyglycolide, polycyanoacrylate, polycaprolactone, polyanhydride, polyorthoester and/or polyphosphazene, or copolymer between the above polymers, such as: polyglycolic acid (PGA), polylactic acid (PLA), poly-e-caprolactone (PCL), and the like.

The degradation speed of the scaffold can be adjusted according to specific requirements and use scenes, usually, the aneurysm can be reduced to disappear in about six months after the scaffold is implanted, and therefore the optimal degradation time of the scaffold is 1-2 years for the keel scaffold and 6-1 year for the dense-net scaffold. According to a particularly preferred embodiment of the invention, the material of the keel frame 1 is preferably magnesium-based alloy, and the material of the dense-mesh frame 2 is preferably polylactic acid.

According to a preferred embodiment of the present invention, the keel support 1 and the dense mesh support 2 are fixed by laser welding, adhesion or mechanical connection.

Further, the shape and density of the stent are determined by the design of the weaving or cutting process.

Furthermore, the forming process and the performance of the degradable double-layer bracket are easy to control and guarantee.

As shown in fig. 2, a degradable double-layered stent according to another preferred embodiment of the present invention is provided, which is substantially the same as the previous embodiment, except that the degradable double-layered stent is woven with developing wires 4, and the developing wires 4 are woven in a dense-mesh stent 2.

The degradable double-layer stent provided according to the above preferred embodiment has the following working principle:

when in a pushing configuration, the degradable double-layer stent is placed in a micro-catheter (not shown) for delivery in a pressing and holding state, only the outer-layer keel stent 1 is in contact with the wall of the micro-catheter, and compared with the dense-mesh stent 2 which is in direct contact with the micro-catheter, the contact area is relatively small, and the friction resistance is smaller; further, when this double-deck support is in the blood vessel, radial holding power to the vascular wall also is provided by fossil fragments support 1, and fossil fragments support 1 has higher intensity and holding power, compares dense net support 2 and is difficult to take place to cave in, retract, shift, thereby dense net support 2 is located vascular pathological change department and guarantees with mesh density as high as possible that the tumor body is effectively blocked up, plays the treatment purpose.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.