Thrombectomy stent with tension-torsion coupling effect

Abstract

The present application provides a thrombus removal stent with a torsion coupling effect, which relates to the technical field of medical devices, and includes a cutting portion and a braided portion that are coaxially connected in sequence; the cutting portion includes a torsion section, a transition section, and a cutting section that are sequentially arranged in a direction away from the braided portion; the torsion section is configured such that when the cutting portion is pulled, the torsion section twists and deforms around the axis of the braided portion and expands outward, driving the transition section and the cutting section to twist around the axis of the braided portion; the cutting section is configured such that when the cutting portion is pulled, the thrombus on the blood vessel wall is twisted and cut; the braided portion is configured to collect the thrombus removed by the cutting section. The cutting portion adopts the structural arrangement of the torsion section, the transition section, and the cutting section, and can twist and cut the thrombus on the blood vessel wall during the axial movement along the blood vessel, and expand outward at the same time to better fit the blood vessel wall, so as to improve the effect of removing the thrombus on the blood vessel wall.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a thrombus removal stent with a tension-torsion coupling effect. Background Art

[0002] Currently, the treatments for deep vein thrombosis (DVT) mainly include anticoagulation therapy, local thrombolysis and mechanical thrombectomy. However, some patients have contraindications to anticoagulation or thrombolysis, so mechanical thrombectomy becomes the main choice.

[0003] Mechanical thrombectomy mainly includes aspiration thrombectomy and stent thrombectomy. Aspiration thrombectomy causes a large amount of blood loss and has poor therapeutic effects on subacute and chronic thrombi. Stent thrombectomy causes less blood loss and complications, has a short operation time, less trauma, and low cost, and has been increasingly chosen. However, for subacute or chronic thrombi, there are more fibrin components inside the thrombus. If not treated in time, over time, a large amount of fibrous connective tissue will be deposited and organized and firmly adhere to the inner wall of the blood vessel. The existing thrombectomy stent is manufactured with a traditional diamond structure. When placed in a blood vessel for thrombectomy, the stent only moves along the axis of the blood vessel to cut the thrombus, and cannot be torsional cut. The thrombectomy effect is poor for chronic thrombi with firm adhesion. In addition, the diameter of the existing thrombectomy stent shrinks when it is pulled, and it cannot better adhere to the wall to remove the thrombus on the inner wall of the blood vessel, further reducing the thrombectomy effect. Therefore, in response to this problem, it is still necessary to study the existing thrombectomy stent to further improve the thrombectomy effect and reduce the treatment risk.

[0004] Therefore, there is a need for a new thrombectomy stent that can achieve twisting cutting while moving along the axial direction of the blood vessel and can also expand outward to better fit the blood vessel wall and improve the effect of removing thrombi on the blood vessel wall. Summary of the invention

[0005] In view of this, an embodiment of the present specification provides a thrombus removal stent with a tension-torsion coupling effect, which can twist and cut the thrombus on the blood vessel wall during the axial movement along the blood vessel. At the same time, as the stent is stretched and expanded outward, it better fits the blood vessel wall to improve the effect of removing the thrombus on the blood vessel wall.

[0006] The embodiments of this specification provide the following technical solutions:

[0007] The embodiment of the present specification provides a thrombus removal stent with a pulling-torsion coupling effect, comprising a cutting portion and a braided portion coaxially connected in sequence;

[0008] The cutting portion comprises a pulling and twisting section, a transition connecting section and a cutting section which are sequentially arranged in a direction away from the braiding portion;

[0009] The pulling and twisting section is configured such that: when the cutting section is pulled, the pulling and twisting section twists and deforms around the axis of the braided section and expands outward, driving the transition section and the cutting section to twist around the axis of the braided section;

[0010] The cutting section is configured to: twist and cut the thrombus on the blood vessel wall when the cutting portion is pulled;

[0011] The braided portion is configured to collect thrombus removed by the cutting segment.

[0012] Preferably, the pulling and twisting section includes a plurality of pulling and twisting units, each of which is composed of a unit cell and a plurality of extension sections arranged around the unit cell;

[0013] A plurality of unit cells are arranged around the axis of the braided portion and arranged in an array in sequence, and adjacent unit cells are connected by extension sections;

[0014] The transition connecting section includes a plurality of connecting rods, which are connected one by one to a plurality of extension sections of the pulling and twisting section away from one end of the braiding section, and one end of the connecting rod away from the extension section is connected to the cutting section;

[0015] When the torsion section is pulled, several unit cells and extension sections twist and deform around the axis of the braided portion and expand outward, driving several connecting rods to twist and deform around the axis of the braided portion and expand outward, so that the cutting section twists and cuts the thrombus on the blood vessel wall.

[0016] Preferably, the braided portion includes a filter segment and a tip head;

[0017] The filter segment is formed by a number of braided wires woven together;

[0018] A plurality of limit rings are arranged at one end of the pulling and twisting section close to the filter section, and the plurality of limit rings are evenly distributed circumferentially around the axis of the filter section;

[0019] Every two braided wires form a group of braiding units, and a number of braiding units correspond to a number of limiting rings one by one;

[0020] The two braiding wires in each braiding unit are both inserted into the corresponding limiting rings, and the middle section of the braiding wire is located on the limiting ring, and the two ends of the braiding wire meet on the tip.

[0021] Preferably, any two adjacent braided wires are braided with each other in a one-on-one manner.

[0022] Preferably, the cutting section comprises two cutting wires which are symmetrical about the axis of the braided portion and connected to each other;

[0023] Both ends of each cutting wire are bent toward the direction close to the axis of the braided portion to form an arc-shaped cutting section;

[0024] One end of the cutting section is arranged close to the braided part along the axial direction of the braided part, and the other end of the cutting section is arranged away from the braided part along the axial direction of the braided part.

[0025] Preferably, a fixing ring is provided at one end of the cutting section away from the braided portion, and the fixing ring is used for connecting the catheter.

[0026] Preferably, the rib width of the cutting wire is greater than the rib width of the connecting rod and the rib width of the pulling and twisting unit.

[0027] Preferably, the configuration of the tension-twist section can be a left-right symmetrical tension-twist structure, a centrally symmetrical tension-twist structure or a bidirectional torsion structure.

[0028] Preferably, the cutting portion is made of NiTi shape memory alloy.

[0029] Preferably, the material of the braided wire is NiTi shape memory alloy.

[0030] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0031] 1. The cutting part adopts a structure of a pulling and twisting section, a transition connecting section and a cutting section. During the thrombus removal process, the pulling and twisting section can be twisted and deformed and expanded outwards by the pulling force, driving the transition connecting section and the cutting section to twist and deform and expand outwards. The thrombus on the blood vessel wall is twisted and cut by the cutting section, thereby improving the thrombus removal effect. At the same time, the cutting section is more closely attached to the blood vessel wall after being pulled outwards, and the thrombus removal effect is further enhanced;

[0032] 2. The degree of expansion and torsional deformation of the entire cutting part can be adjusted by pulling force to adapt to the hardness of blood clots in various parts of the blood vessels and the different diameters of the blood vessels, so as to achieve a better thrombus removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a schematic diagram of the overall structure in the embodiment of the present application;

[0035] Figure 2 Schematic diagram of the configuration of the tension-twist unit in the embodiment of the present application;

[0036] Figure 3 It is a schematic diagram of the bilaterally symmetrical tension-twist structure in the present application;

[0037] Figure 4 It is a schematic diagram of the centrosymmetric tension-twist structure in the present application;

[0038] Figure 5 is a schematic diagram of a bidirectional torsion structure in the present application;

[0039] Figure 6 is a schematic diagram of a cutting portion in an embodiment of the present application;

[0040] Figure 7 It is a schematic diagram of the structure of the connection between the braiding unit and the twisting section in the embodiment of the present application;

[0041] Figure 8 It is a schematic diagram of the overall assembly of the catheter, the core shaft rod and the stent in the embodiment of the present application.

[0042] Figure numerals: 1, cutting part; 11, pulling and twisting section; 111, pulling and twisting unit; 1111, unit cell; 1112, extension section; 12, transition connection section; 121, connecting rod; 13, cutting section; 131, cutting wire; 2, weaving part; 21, filter section; 211, weaving unit; 2111, weaving wire; 22, tip head; 3, fixing ring; 4, limiting ring. DETAILED DESCRIPTION

[0043] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0044] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0045] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0046] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0047] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0048] In view of this, the inventor conducted in-depth research and improved exploration on the structure of the thrombectomy stent and found that when the existing thrombectomy stent is placed in a blood vessel to remove the thrombus, the stent only moves along the axial direction of the blood vessel to cut the thrombus, and cannot be twisted and cut, which is less effective for chronic thrombi with strong adhesions. In addition, the diameter of the existing thrombectomy stent shrinks when it is pulled, and it cannot better adhere to the wall to remove the thrombus on the inner wall of the blood vessel, further reducing the thrombectomy effect.

[0049] Based on this, the embodiment of this specification proposes a thrombectomy stent with a pull-twist coupling effect, including a cutting portion and a braided portion. The cutting portion adopts a unique pull-twist coupling structure design. When the stent is used to remove the thrombus, it is torsionally deformed and expanded outward under the action of tension. On the one hand, it can produce a rotational cutting effect on chronic or old thrombi that are firmly adhered, making the thrombus easier to separate from the blood vessel wall and avoiding damage to the inner wall of the blood vessel caused by forcibly pulling the thrombectomy stent. On the other hand, it can make the cutting portion fit more closely to the inner wall of the blood vessel and remove the thrombus more thoroughly.

[0050] The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

[0051] like Figure 1 As shown, an embodiment of the present specification provides a thrombus removal stent with a tension-torsion coupling effect, comprising a cutting portion 1 and a braided portion 2 coaxially connected in sequence.

[0052] The cutting portion 1 comprises a pulling and twisting section 11 , a transition connecting section 12 and a cutting section 13 which are sequentially arranged in a direction away from the braided portion 2 .

[0053] like Figure 1 and Figure 2 As shown, the torsion section 11 includes a plurality of torsion units 111, each of which is composed of a unit cell 1111 and four extension segments 1112 evenly distributed around the unit cell 1111. The unit cell 1111 is in a circular ring shape, and each extension segment 1112 surrounding the unit cell 1111 is tangent to the outer periphery of the unit cell 1111.

[0054] A plurality of pulling and twisting units 111 are evenly divided into two layers along the axial direction of the woven portion 2, and a plurality of single cells 1111 in each layer are arranged in a circular array around the axis of the woven portion 2, and adjacent single cells 1111 are fixedly connected by extension sections 1112, and the rotation direction of the four extension sections 1112 connected to any single cell 1111 is the same as the rotation direction of the four extension sections 1112 connected to other single cells 1111.

[0055] During actual use, when the cutting portion 1 is pulled, the extension segment 1112 distributed along the axial direction of the braided portion 2 will drive the unit cell 1111 to rotate under the action of the tension, and then drive the other extension segments 1112 on the unit cell 1111 to rotate together, so that the entire torsional segment 11 is twisted and deformed around the axis of the braided portion 2, and then the connected transition segment 12 and cutting segment 13 will also undergo the same torsional deformation around the axis of the braided portion 2, so as to improve the cutting effect of the thrombus; and in this process, the connected extension segments 1112 between adjacent unit cells 1111 will pull each other and expand outward, thereby driving the transition segment 12 and the cutting segment 13 to undergo the same outward expansion and deformation, so as to better fit the inner wall of the blood vessel.

[0056] The configuration of the torsion section 11, the rib width, the number of layers of the torsion unit 111, the configuration of the single cell 1111 and the angle between the extension section 1112 and the single cell 1111 can all be adjusted according to the blood vessel wall and the type of thrombus, and different specifications can be designed to achieve different torsion effects and mechanical properties, thereby improving the cutting ability of the cutting section 13 for thrombus and its compatibility with the blood vessel wall, and reducing damage to the blood vessel wall.

[0057] In other embodiments, the configuration of the unit cell 1111 may also be a regular hexagon, and the extension segments 1112 are correspondingly adjusted to six, which are respectively arranged at fixed angles with the six side lines of the unit cell 1111.

[0058] In other embodiments, Figures 3 to 5 As shown, the configuration of the twisting section 11 can also be a bilaterally symmetrical twisting structure, a centrally symmetrical twisting structure, and a bidirectional twisting structure. Among them, the bidirectional twisting structure is a structural design in which multiple layers of twisting units 111 are designed with opposite rotation directions. Multiple layers of twisting units 111 with different rotation directions can make the cutting part 1 as a whole produce a larger angle of rotational cutting effect, thereby improving the efficiency and effect of thrombus removal.

[0059] like Figure 1 , Figure 2 and Figure 6As shown, the transition connecting section 12 includes a plurality of connecting rods 121, and the plurality of connecting rods 121 are fixedly connected to a plurality of extension sections 1112 at one end of the pulling and twisting section 11 away from the braided portion 2, and the other end of each connecting rod 121 away from the extension section 1112 is fixedly connected to the cutting section 13. When the pulling and twisting section 11 is pulled to torsionally deform and expand outward, the connecting rod 121 can transmit the force to drive the cutting section 13 to torsionally deform and expand outward.

[0060] The cutting section 13 includes two cutting wires 131 which are symmetrical and connected to each other about the axis of the braided portion 2. The connecting rods 121 are evenly divided into two groups, and are connected to the two cutting wires 131 respectively.

[0061] Both ends of each cutting wire 131 are bent toward the direction close to the axis of the braided portion 2, and are connected to each other to form a cutting segment 13 with an arc-shaped curved surface profile. One end of the cutting segment 13 is arranged close to the braided portion 2 along the axis of the braided portion 2, and the other end of the cutting segment 13 is arranged away from the braided portion 2 along the axis of the braided portion 2. The overall arc-shaped curved surface design, on the one hand, is convenient for being put into the outer tube, and on the other hand, can better fit the inner wall of the blood vessel and improve the cutting effect of thrombus.

[0062] The cutting section 13 is also provided with a fixing ring 3 at one end away from the braided portion 2, and the fixing ring 3 is used to connect the catheter and the mandrel rod. The mandrel rod is a rod body used to push the stent as a whole to move axially in the thrombus removal link.

[0063] The cutting wire 131 has a greater width than the connecting rod 121 and the twisting unit 111 , so that the cutting wire 131 is less likely to bend or break during the thrombus removal process, thereby preventing the thrombus removal effect from being affected.

[0064] like Figure 1 , Figure 2 and Figure 7 As shown, the braided portion 2 includes a filter segment 21 and a tip head 22. The filter segment 21 is formed by braiding a plurality of braided wires 2111 together, and is used to collect the thrombus removed by the cutting segment 13. In this embodiment, there are 12 braided wires 2111, and every two braided wires 2111 form a braided unit 211.

[0065] A plurality of limiting rings 4 are arranged at one end of the pulling and twisting section 11 close to the filter section 21. In this embodiment, there are 6 limiting rings 4 in total, and the 6 limiting rings 4 are evenly distributed around the axis of the filter section 21 in the circumferential direction.

[0066] The six groups of braided units 211 are arranged one by one corresponding to the six limiting rings 4. The two braided wires 2111 in each group of braided units 211 are both inserted into the corresponding limiting rings 4, and the middle section of each braided wire 2111 is located on the corresponding limiting rings 4, and the two ends of the braided wires 2111 meet on the tip 22. Any two adjacent braided wires 2111 are braided with each other in a one-on-one form. By braiding with each other in a one-on-one form and limiting by the limiting rings 4, the movement of the braided wires 2111 can be effectively limited, preventing the braided wires 2111 from rotating and displacing and causing thrombus to fall off.

[0067] In other embodiments, the number of braided wires 2111 and the number of limiting rings 4 can be adjusted according to actual needs and are not further limited herein.

[0068] The cutting part 1 is made of NiTi shape memory alloy and is made by laser cutting. The braided wire 2111 is made of NiTi shape memory alloy.

[0069] like Figure 8 As shown, when actually removing the thrombus, the stent as a whole needs to be used together with the mandrel rod and the guide rod. By cooperating with the mandrel rod, the dynamic adjustment of the overall shape of the stent can be achieved. The specific operation process is as follows: After the stent is implanted in the blood vessel, it is released and fits with the blood vessel wall. When the diameter of a certain section of the blood vessel wall is large and the stent as a whole cannot fit the wall to complete the thrombus removal, the catheter is fixed and the mandrel rod is pushed in the direction away from the catheter. The mandrel rod drives the braided part 2 to move in the direction away from the cutting part 1. The two ends of the cutting part 1 are pulled to produce a tension-torsion coupling effect. On the one hand, the cutting section 13 is twisted and deformed, which produces a rotational removal effect on the thrombus, so that the thrombus is separated from the blood vessel wall; on the other hand, the diameter of the entire section of the cutting part 1 becomes larger and fits with the blood vessel wall to facilitate the removal and separation of the thrombus. Subsequently, the stent is repeatedly pushed and pulled as a whole to remove the thrombus. After the thrombus removal of the current larger diameter blood vessel wall is completed, the mandrel rod is released, and the stent as a whole can be restored to its original state to avoid damage to the blood vessel wall caused by the overall outer diameter being too large. During the thrombectomy process, when encountering chronic or old thrombi that are difficult to remove, repeated actions of slowly pushing and then gradually relaxing can be taken to complete the removal of the chronic or old thrombi that are difficult to remove, effectively avoiding damage to the blood vessel wall caused by forcibly pushing and pulling the stent as a whole.

[0070] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0071] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A thrombectomy stent with a tension-torsion coupling effect, characterized in that: It comprises a cutting part (1) and a braiding part (2) which are coaxially connected in sequence; The cutting portion (1) comprises a pulling and twisting section (11), a transition connection section (12) and a cutting section (13) which are sequentially arranged in a direction away from the braided portion (2); The pulling and twisting section (11) is configured such that: when the cutting section (1) is pulled, the pulling and twisting section (11) twists and deforms around the axis of the braided section (2) and expands outward, driving the transition section (12) and the cutting section (13) to twist around the axis of the braided section (2); The cutting section (13) is configured to twist and cut the thrombus on the blood vessel wall when the cutting portion (1) is pulled; The braided portion (2) is configured to collect the thrombus removed by the cutting segment (13).

2. The thrombus removal stent with tension-torsion coupling effect according to claim 1, characterized in that: The pulling and twisting section (11) comprises a plurality of pulling and twisting units (111), each of which is composed of a unit cell (1111) and a plurality of extension sections (1112) arranged around the unit cell (1111); A plurality of the unit cells (1111) are disposed around the axis of the woven portion (2) and arranged in an array in sequence, and adjacent unit cells (1111) are connected via extension sections (1112); The transition connecting section (12) comprises a plurality of connecting rods (121), wherein the plurality of connecting rods (121) are connected one by one to a plurality of extension sections (1112) at one end of the pulling and twisting section (11) away from the braided portion (2), and one end of the connecting rod (121) away from the extension section (1112) is connected to the cutting section (13); When the pulling and twisting section (11) is pulled, a plurality of the unit cells (1111) and the extension section (1112) are twisted and deformed around the axis of the braided portion (2) and expand outward, driving a plurality of connecting rods (121) to be twisted and deformed around the axis of the braided portion (2) and expand outward, so that the cutting section (13) twists and cuts the thrombus on the blood vessel wall.

3. The thrombus removal stent with tension-torsion coupling effect according to claim 2, characterized in that: The braided portion (2) comprises a filter screen segment (21) and a tip head (22); The filter screen segment (21) is formed by a plurality of braided wires (2111) being braided together; A plurality of limiting rings (4) are arranged at one end of the pulling and twisting section (11) close to the filter section (21), and the plurality of limiting rings (4) are evenly distributed in the circumferential direction around the axis of the filter section (21); Every two braided wires (2111) form a group of braided units (211), and a plurality of braided units (211) correspond one by one to a plurality of limiting rings (4); The two braiding wires (2111) in each group of braiding units (211) are both inserted into the corresponding limiting ring (4), and the middle section of the braiding wire (2111) is located on the limiting ring (4), and the two ends of the braiding wire (2111) meet on the tip head (22).

4. The thrombus removal stent with tension-torsion coupling effect according to claim 3, characterized in that: Any two adjacent braided wires (2111) are braided with each other in a one-on-one manner.

5. The thrombus removal stent with tension-torsion coupling effect according to claim 2, characterized in that: The cutting section (13) comprises two cutting wires (131) which are symmetrical about the axis of the braided portion (2) and connected to each other; Both ends of each cutting wire (131) are bent in a direction close to the axis of the braided portion (2) to form a cutting section (13) in the shape of an arc-shaped curved surface; One end of the cutting section (13) is arranged close to the braided portion (2) along the axial direction of the braided portion (2), and the other end of the cutting section (13) is arranged away from the braided portion (2) along the axial direction of the braided portion (2).

6. The thrombus removal stent with tension-torsion coupling effect according to claim 5, characterized in that: A positioning ring (3) is provided at one end of the cutting section (13) away from the braided portion (2), and the positioning ring (3) is used for the core shaft rod to penetrate.

7. The thrombus removal stent with tension-torsion coupling effect according to claim 5, characterized in that: The rib width of the cutting wire (131) is greater than the rib width of the connecting rod (121) and the rib width of the pulling and twisting unit (111).

8. The thrombus removal stent with tension-torsion coupling effect according to claim 2, characterized in that: The configuration of the tension-twist section (11) is a left-right symmetrical tension-twist structure, a centrally symmetrical tension-twist structure or a bidirectional torsion structure.

9. The thrombus removal stent with tension-torsion coupling effect according to claim 1, characterized in that: The material of the cutting part (1) is NiTi shape memory alloy.

10. The thrombus removal stent with tension-torsion coupling effect according to claim 3, characterized in that: The material of the braided wire (2111) is NiTi shape memory alloy.

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