A stent with auxetic structure

Abstract

This invention discloses a thrombectomy stent with a tensile structure. The stent includes a self-expanding cut segment and a braided segment connected to the cut segment. The cut segment includes a tensile structure, which, when subjected to tension, causes the cut segment to expand radially. This invention solves the problem that existing thrombectomy stents, when subjected to tension and shrinkage, cannot completely remove thrombi from blood vessels.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, and particularly relates to a thrombectomy stent with a dilatancy structure. BACKGROUND

[0002] Deep vein thrombosis (DVT) is the blood coagulation in the deep veins of the limbs or pelvis, which is a common clinical disease with non-specific signs of lower limb pain, swelling, fever or blue-green sputum. At present, the treatment of DVT mainly adopts mechanical thrombectomy, which mainly includes suction thrombectomy and stent thrombectomy. The stent thrombectomy usually extends the thrombectomy stent into the blood vessel to remove the thrombus on the inner wall of the blood vessel.

[0003] The existing thrombectomy stent is usually manufactured by using a traditional rhombic structure. When the thrombectomy stent is placed in the blood vessel for thrombectomy, the diameter of the thrombectomy stent will be reduced under tension, which causes the thrombectomy stent to be unable to completely remove the thrombus in the blood vessel. Therefore, the thrombectomy stent needs to be placed in the blood vessel multiple times to complete the thrombectomy, which undoubtedly increases the risk of thrombus detachment and patient infection. SUMMARY

[0004] Therefore, the present application provides a thrombectomy stent with a dilatancy structure to solve the problem that the existing thrombectomy stent is reduced in diameter under tension, which causes the thrombectomy stent to be unable to completely remove the thrombus in the blood vessel.

[0005] The present application provides the following technical solutions:

[0006] The present application provides a thrombectomy stent with a dilatancy structure, which comprises a self-expandable cutting segment and a braided segment connected with the cutting segment. The cutting segment comprises a dilatancy structure, and the dilatancy structure drives the cutting segment to expand radially at least when subjected to tension.

[0007] Further, the cutting segment further comprises:

[0008] A cutting ring is connected with one end of the dilatancy structure away from the braided segment, and the cutting ring is used for cutting the thrombus attached to the inner wall of the blood vessel.

[0009] Further, one end of the cutting ring away from the dilatancy structure is provided in a bevel shape.

[0010] Further, the cutting segment further comprises:

[0011] A stent structure is connected with the dilatancy structure to improve the mechanical support performance of the cutting segment.

[0012] Further, the cutting segment is cut from a memory alloy material.

[0013] Further, the braided section comprises a plurality of braided wires, the plurality of braided wires are arranged on the plurality of limiting members of the cutting section and interweaved to form the braided section.

[0014] Wherein, at least one of the braided wires in each of the limiting members is arranged to be compressed by other braided wires in the limiting member.

[0015] Further, the braided section comprises a closing section, the closing section is located at one end of the braided section away from the cutting section, and the aperture of the closing section gradually decreases from the proximal end to the distal end.

[0016] Further, the closing section is arranged in a tapered shape, so that the aperture of the closing section gradually decreases from the proximal end to the distal end, to prevent small thrombus from falling off.

[0017] Further, the braided wire is a NiTi wire.

[0018] Further, the thrombus extraction stent further comprises a mandrel rod, the mandrel rod is used for inserting into the braided section and pushing the braided section, so that the auxetic structure is subjected to tension and expands radially.

[0019] Compared with the prior art, the thrombus extraction stent with an auxetic structure can completely remove the thrombus in the blood vessel by arranging the auxetic structure on the cutting section, so that the cutting section expands under tension in the case of pulling the cutting section to extract the thrombus, thereby solving the problem that the diameter of the existing thrombus extraction stent decreases after being subjected to tension, which leads to difficulty in completely extracting the thrombus in the blood vessel. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the thrombus extraction stent with an auxetic structure according to the embodiment of the present application;

[0021] Figure 2 It is a schematic diagram of the auxetic unit with different configurations according to the embodiment of the present application;

[0022] Figure 3 It is a structural schematic diagram of the cutting section according to the embodiment of the present application;

[0023] Figure 4 It is a top view of the thrombus extraction stent with an auxetic structure according to the embodiment of the present application;

[0024] Figure 5 It is a connection schematic diagram of the auxetic structure and the stent structure according to the embodiment of the present application;

[0025] Figure 6 It is a structural schematic diagram of the connection between the cutting section and the braided section according to the embodiment of the present application;

[0026] Figure 7Figure 2 is a side view of a core shaft rod of a stent retriever with a tensile structure according to an embodiment of the present application;

[0027] The reference signs of the present application are as follows:

[0028] 10, cutting section; 11, tensile structure; 12, cutting ring; 13, stent structure; 14, limiting member;

[0029] 20, braided section; 21, braided wire; 22, connecting head;

[0030] 30, core shaft rod;

[0031] 40, guide ring;

[0032] 50, catheter. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and explained below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0034] Obviously, the drawings in the following description are only some examples or embodiments of the present application, and for those of ordinary skill in the art, the present application can be applied to other similar scenarios without creative labor on the basis of these drawings. In addition, it can be understood that although the efforts made in this development process can be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacture or production changes based on the technical content disclosed in the present application are only routine technical means and should not be understood as insufficient disclosure of the present application.

[0035] In the present application, "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present application can be combined with other embodiments without conflict.

[0036] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0037] Example 1

[0038] like Figure 1 As shown, this embodiment provides a thrombectomy bracket with a tensile structure. The thrombectomy bracket includes a self-expanding cut section 10 and a braided section 20 connected to the cut section 10.

[0039] The cutting segment 10 is used to cut the thrombus in the blood vessel. The cutting segment 10 can be fixedly connected to the braided segment 20 or detachably connected to the braided segment 20.

[0040] Among them, the braided section 20 is a mesh structure used to collect the thrombus cut off by the cutting section 10, and to prevent the thrombus from falling off and causing pulmonary embolism. For example, the braided section 20 is a collection net with a diamond-shaped mesh.

[0041] The cutting segment 10 includes a tensile structure 11. When subjected to tension, the tensile structure 11 at least causes the cutting segment 10 to expand radially, which solves the problem that existing thrombectomy stents are difficult to completely remove thrombi from blood vessels due to tension and contraction.

[0042] Specifically, when the expansion structure 11 is subjected to tension, due to the expansion effect, the expansion structure 11 itself can expand radially, and then the expansion structure 11 can drive the cutting segment 10 to expand radially.

[0043] The auxetic structure 11 is composed of a plurality of auxetic units arranged along the circumference of the cutting section 10.

[0044] As shown in Figure 2 , the auxetic unit can be a concave auxetic unit a, a rotating auxetic unit b, or a symmetric auxetic unit c.

[0045] Among them, by adjusting the diameter of the auxetic structure 11 and the configuration, muscle width and angle of the auxetic unit, different auxetic effects and mechanical properties can be achieved, thereby further improving the adaptability of the stent to the shape of the blood vessel and reducing the damage to the blood vessel.

[0046] Preferably, the auxetic structure 11 can be composed of a ring structure composed of a plurality of auxetic units, so that the auxetic structure 11 can expand in all directions when the auxetic structure 11 is stretched to remove the stent.

[0047] Among them, the auxetic structure 11 can be directly connected with the braided section 20, or connected with the braided section 20 through a connecting ring.

[0048] By expanding radially under tension of the auxetic structure 11, the problem of existing stent placement in the blood vessel for thrombectomy is solved. When the stent is stretched, it shrinks, causing the stent to not tightly adhere to the inner wall of the blood vessel, and the thrombus on the inner wall of the blood vessel cannot be completely removed and needs to be placed multiple times to completely remove the thrombus. The risk of thrombus detachment and patient infection is reduced.

[0049] As shown in Figure 1 , 3 ~4, the cutting section 10 further comprises a cutting ring 12, the cutting ring 12 is connected with one end of the auxetic structure 11 away from the braided section 20, and the cutting ring 12 is used to cut the thrombus attached to the inner wall of the blood vessel when in the expanded state.

[0050] Among them, the cutting ring 12 can be a ring structure, such as a circular ring, and the cutting ring 12 can also be a cylindrical ring structure.

[0051] Among them, the cutting ring 12 can be directly connected with the auxetic structure 11, or connected with the auxetic structure 11 through a plurality of connecting rods.

[0052] Preferably, the cutting ring 12 is connected with the auxetic structure 11 through a plurality of connecting rods arranged circumferentially.

[0053] Among them, in the case that the cutting section 10 comprises the cutting ring 12 and the auxetic structure 11, the cutting ring 12 is connected with the first end of the auxetic structure 11, and the second end of the auxetic structure 11 is connected with the braided section 20.

[0054] Specifically, in the case of cutting the thrombus on the inner wall of the blood vessel, the cutting section 10 and the braided section 20 are placed in the blood vessel, the cutting section 10 can expand to conform to the inner wall of the blood vessel, and then the worker pulls the cutting ring 12 to cut the thrombus on the inner wall of the blood vessel, while the tensile structure 11 can expand outward under the tension of the cutting ring 12, and then the tensile structure 11 drives the cutting ring 12 to expand outward at the same time, so that the cutting ring 12 can cut the thrombus attached to the inner wall of the blood vessel, and can avoid the thrombus missing to the outside, thereby solving the problem that the existing thrombus-removing stent is prone to shrinkage under tension and difficult to completely remove the thrombus. Thrombus attached to the blood vessel wall is cut by the cutting ring 12, so that the thrombus in the blood vessel can be more completely removed.

[0055] In some embodiments, as shown in Figure 3 the end of the cutting ring 12 away from the tensile structure 11 is provided in a bevel shape, that is, an arc-shaped opening is formed at the end of the cutting ring 12, so as to facilitate the cutting of the thrombus on the inner wall of the blood vessel, and also facilitate the accommodation of the cutting section 10 in the sheath.

[0056] In some embodiments, as shown in Figure 5 the cutting section 10 further comprises a stent structure 13 connected with the tensile structure 11, so as to improve the mechanical support performance of the thrombus-removing stent.

[0057] In some embodiments, the stent structure 13 is a conventional non-tensile structure.

[0058] In some embodiments, the stent structure 13 is composed of a plurality of conventional stent units, such as a plurality of rhombic non-tensile units.

[0059] In some embodiments, the stent structure 13 can be an annular structure composed of a plurality of conventional stent units, and the stent structure 13 is coaxially connected with the tensile structure 11.

[0060] Specifically, the first end of the stent structure 13 is connected with the tensile structure 11, and the second end of the stent structure 13 is connected with the braided section 20; or the first end of the stent structure 13 is connected with the cutting ring 12, and the second end of the stent structure 13 is connected with the tensile structure 11.

[0061] In some embodiments, the plurality of tensile units included in the tensile structure 11 and the plurality of conventional stent units included in the stent structure 13 can be alternately arranged, and the expansion ability of the tensile units is stronger than the contraction ability of the stent structure 13, so that in the case that the tensile structure 11 and the stent structure 13 are simultaneously tensioned, the cutting section 10 can still expand outward due to the expansion ability of the tensile units being stronger than the contraction ability of the stent structure 13.

[0062] By adopting a hybrid structure design that combines the expansion structure 11 and the support structure 13 in the cutting segment 10, the thrombectomy support can maintain the expansion effect while improving the mechanical support performance of the support.

[0063] In some of these embodiments, the cut segment 10 is cut from a shape memory alloy material so that the cut segment 10 has the ability to expand on its own and can shrink back to its original state after being stretched and expanded under the action of the stretching structure 11.

[0064] The cut segment 10 is made of NiTi shape memory alloy material by laser cutting.

[0065] Specifically, the expansion structure 11, the cutting ring 12, and the support structure 13 are all made of shape memory alloy material.

[0066] like Figure 1 , 6 As shown, the braided section 20 includes a plurality of braided filaments 21, which are respectively threaded onto a plurality of limiting members 14 on the cutting section 10 and interwoven to form the braided section 20. In this case, at least one braided filament 21 in each limiting member 14 is pressed and positioned by other braided filaments 21 in the limiting member 14.

[0067] The limiting member 14 can be a limiting ring or a limiting hole, used to limit the braided wire 21 and prevent the braided wire 21 from shifting.

[0068] Specifically, when the limiting member 14 is a limiting ring, the limiting ring can be directly set at the end of the cutting section 10 near the braiding section 20, or it can be set at the end of the cutting section 10 near the braiding section 20 through a connecting rod; when the limiting member 14 is a limiting hole, the limiting member 14 is opened at the end of the cutting section 10 near the braiding section 20.

[0069] In this way, by pressing and setting at least one braided wire 21 within the limiting member 14 with other braided wires 21 and limiting the braided wire 21 by the limiting member 14, it is possible to prevent the braided segment 20 from rotating and shifting, causing the thrombus to fall off the braided segment 20.

[0070] Preferably, the braided section 20 includes 12 braided filaments 21, and there are 6 limiting members 14. Each limiting member 14 has 2 braided filaments 21 threaded inside, one of which passes from right to left and the other passes from left to right and is folded back and knotted below the limiting ring, thus forming a "one-over-one" configuration. The braided filaments 21 can pass through the limiting members 14 from the outer surface of the cut section 10 to the inner surface.

[0071] The weaving wire 21 is knotted below the limiting ring, which means that one weaving wire 21 in the limiting ring is knotted below the limiting member 14 after being folded back and intersecting with the other weaving wires 21 to form the weaving section 20.

[0072] The midpoint of the weaving wire 21 can be located on the limiting ring, and the two ends of the weaving wire 21 are gathered at one end of the weaving section 20 away from the cutting section 10, and the two ends of the weaving wire 21 are fixed together by the connecting head 22.

[0073] The weaving section 20 also includes a closing section, and the aperture of the closing section gradually decreases from the proximal end to the distal end to avoid small thrombi from falling off the weaving section 20.

[0074] The proximal end is the end of the closing section close to the cutting section 10, and the distal end is the end of the closing section away from the cutting section 10.

[0075] The weaving section 20 also includes a straight section, one end of which is connected to the cutting section 10, and the other end is connected to the closing section.

[0076] For example, the straight section is connected to the auxetic structure 11 of the cutting section 10 through a connecting rod.

[0077] The straight section and the closing section of the weaving section 20 are both woven by the weaving wire 21 and are an integral structure.

[0078] The closing section can be provided in a circular truncated cone shape, a conical shape, a spherical shape, etc., so that the aperture of the closing section gradually decreases from the proximal end to the distal end in the case of gathering the ends of the weaving wire 21.

[0079] Preferably, as shown in Figure 1 The closing section is provided in a conical shape to gradually decrease the aperture of the closing section from the proximal end to the distal end to prevent small thrombi from falling off.

[0080] The closing section is provided in a conical shape, and in the case of gathering the ends of the weaving wire 21, the ends of the weaving wire 21 are connected together by the connecting head 22.

[0081] Further, the weaving wire 21 is a NiTi wire, so that the weaving section 20 has self-expanding ability or self-shrinking ability, so that in the case of placing the weaving section 20 in the blood vessel, the weaving section 20 can self-expand to increase the thrombectomy ability.

[0082] For example, in the case of expansion of the weaving section 20 under the action of the auxetic structure 11, if the auxetic structure 11 shrinks, the weaving section 20 can also shrink under the action of the auxetic structure 11 and its own properties.

[0083] The embodiment shortens the length of the stent-retriever into the sheath, so that it is easier to enter the sheath.

[0084] The unique design of the expansion-on-stretch structure 11 of the stent-retriever cutting segment 10 can expand due to the pulling force when the stent-retriever is used to retrieve the thrombus, so that the cutting segment 10 is more closely attached to the inner wall of the blood vessel, and the thrombus is more completely scraped, the number of stent placements is reduced, and the risk of thrombus detachment and patient infection is reduced.

[0085] Embodiment 2

[0086] As shown in Figure 7 The embodiment is a variant of Embodiment 1, and the difference from Embodiment 1 is that the stent-retriever further comprises a mandrel 30.

[0087] The mandrel 30 is used to be inserted into the braided segment 20 to push the braided segment 20, so that the expansion-on-stretch structure 11 is subjected to a pulling force and expands radially.

[0088] Specifically, after the stent-retriever is released into the blood vessel, the cutting segment 10 and the braided segment 20 self-expand to be attached to the blood vessel wall. In the case of a blood vessel with a larger diameter at a certain segment, if the cutting segment 10 and the braided segment 20 cannot be attached to the inner wall of the blood vessel, the mandrel 30 is pushed at this time, so that the mandrel 30 drives the braided segment 20 to pull the expansion-on-stretch structure 11, and then due to the effect of expansion-on-stretch, the diameter of the cutting segment 10 becomes larger to be attached to the inner wall of the blood vessel again. When the blood vessel diameter becomes smaller, the mandrel 30 is released, and the cutting segment 10 can return to the original state due to the material properties of the memory metal, so as to avoid damage to the blood vessel wall caused by the too large diameter of the cutting segment 10 and the braided segment 20. In addition, increasing the diameter and radial support force of the stent-retriever by pushing the mandrel 30 is also beneficial to the removal of acute or chronic thrombus.

[0089] After the stent-retriever finishes retrieving the thrombus, the mandrel 30 is first in a relaxed state, and then the cutting segment 10 of the stent-retriever is recovered into the sheath. On the one hand, the bevel shape of the cutting ring 12 is beneficial to compressing the stent-retriever into the sheath. On the other hand, the expansion-on-stretch structure 11 will shrink in the axial and radial directions after being subjected to pressure, effectively shortening the length of the stent-retriever into the sheath and improving the smoothness of the stent-retriever into the sheath. After the cutting segment 10 is completely in the sheath, the mandrel 30 is pushed to the bottom end, so that the diameter of the braided segment 20 is reduced, and finally the entire stent-retriever is recovered into the sheath together with the thrombus and pulled out of the body.

[0090] The embodiment can make the stent-retriever cutting segment 10 undergo secondary expansion of different amplitudes by cooperation of the expansion-on-stretch structure 11 and the mandrel 30, and dynamically adjust according to the diameters of the blood vessels at different positions, effectively improving the thrombus retrieval effect.

[0091] In some embodiments, asFigure 7 As shown, the cutting section 10 further comprises a guide ring 40 and a conduit 50. The guide ring 40 is arranged at the end of the cutting ring 12 away from the braided section 20, and the conduit 50 is arranged inside the guide ring 40 at one end thereof for insertion of the mandrel rod 30.

[0092] Specifically, the mandrel rod 30 is inserted into the conduit 50 and abuts against the connector 22 to push the connector 22 to stretch the braided section 20, and then the braided section 20 pulls the auxetic structure 11 to expand radially under tension.

[0093] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0094] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that, for those skilled in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A stent having a dilatation structure, characterized by, The thrombus extraction stent comprises a self-expandable cutting section and a braided section connected with the cutting section, the cutting section comprises a stretchable structure, when a mandrel rod is inserted into the braided section to push the braided section so that the stretchable structure is subjected to tension, the stretchable structure itself can expand radially due to the stretchable effect, and at least the cutting section is expanded radially.

2. The thrombus retrieval cage of claim 1, wherein, The cutting section further comprises: a cutting ring connected with one end of the stretchable structure away from the braided section, the cutting ring is used to cut the thrombus attached to the inner wall of the blood vessel.

3. The thrombus retrieval cage of claim 2, wherein, The end of the cutting ring away from the stretchable structure is provided in a bevel shape.

4. The thrombus retrieval cage of claim 1, wherein, The cutting section further comprises: a stent structure connected with the stretchable structure to improve the mechanical support performance of the cutting section.

5. The thrombectomy device of claim 1, wherein, The cutting section is cut from a memory alloy material.

6. The thrombus retrieval cage of claim 1, wherein, The braided section comprises a plurality of braided wires, the plurality of braided wires are correspondingly arranged on a plurality of limiting members of the cutting section and are interwoven to form the braided section. At least one of the braided wires in each limiting member is arranged to be pressed by other braided wires in the limiting member.

7. The thrombus retrieval cage of claim 6, wherein, The braided section comprises a closing section at one end of the braided section away from the cutting section, and the hole diameter of the closing section gradually decreases from the proximal end to the distal end.

8. The thrombus retrieval cage of claim 7, wherein, The closing section is provided in a tapered shape to gradually reduce the hole diameter of the closing section from the proximal end to the distal end to prevent small thrombi from falling off.

9. The thrombus retrieval cage of claim 6, wherein, The braided wire is a NiTi wire.

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