A self-expanding intracranial thrombectomy stent with a gradient mesh density
Patent Information
- Application Number
- CN202611207557.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-11
- Publication Date
- 2026-10-13
AI Technical Summary
[0004]现有的自膨胀式颅内取栓支架，虽能完成取栓操作，但由于其网孔密度固定，难以兼顾不同部位对柔顺性与嵌顿力的要求：若为追求远端柔顺而采用稀疏网孔，则支架中部对硬质血栓的嵌顿力不足，回撤时易滑脱；若为提高中部捕获力而采用致密网孔，则支架整体刚度过大，不仅难以通过迂曲血管到达靶病变，且回撤时顺应性差，易发生轴向拉伸变形，降低血栓夹持的稳定性，增加血栓碎裂与逃逸的风险
[0017]1、该一种具有渐变网孔密度的自膨胀式颅内取栓支架中，将压缩状态下的输送导管推送至颅内靶病变处；利用内导丝及其远端的导丝端进行定位；随后回撤输送导管，使取栓支架一、取栓支架二、取栓支架三与取栓支架四脱离约束并在管腔内自膨胀展开；该取栓支架一、取栓支架二及取栓支架三中，远端取栓支架一的网孔稀疏、近端取栓支架三的网孔密集，有利于支架在释放后能够以远端柔顺性贴壁，并能以近端致密网孔对硬质血栓产生较强的初始包裹与嵌顿；内导丝内侧的送液导管能够将溶栓药液经多组排液导管喷向血栓区域，以配合主支架进行物理软化。
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Figure CN122894015A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of thrombectomy stent technology, and more specifically, to a self-expanding intracranial thrombectomy stent with a gradually varying mesh density. Background Technology
[0002] A self-expanding intracranial thrombectomy stent is an interventional device used to treat acute ischemic stroke. After being delivered to the occluded intracranial artery via a microcatheter, it expands and deploys to capture and remove the thrombus, thereby quickly opening the blood vessel, restoring blood flow, and ultimately reducing disability and mortality rates.
[0003] In existing technologies, self-expanding intracranial thrombectomy stents are often composed of a self-expanding mesh stent body and a guidewire. The guidewire delivers the compressed stent body to the occluded segment via a microcatheter. After the microcatheter is withdrawn, the stent self-expands and unfolds, and the mesh captures the thrombus. The guidewire is then pulled to make the stent radially embed the thrombus and remove it as a whole, ultimately restoring vascular patency.
[0004] Existing self-expanding intracranial thrombectomy stents can perform thrombectomy, but due to their fixed mesh density, they cannot meet the requirements of flexibility and embedment force for different sites. If a sparse mesh is used to pursue distal flexibility, the embedment force of the stent in the middle of the stent is insufficient for hard thrombi, and it is easy to slip out during withdrawal. If a dense mesh is used to improve the capture force in the middle, the overall stiffness of the stent is too large. It is not only difficult to reach the target lesion through tortuous vessels, but also has poor compliance during withdrawal, which easily causes axial tensile deformation, reduces the stability of thrombus clamping, and increases the risk of thrombus fragmentation and escape.
[0005] Based on this, the present invention discloses a self-expanding intracranial thrombectomy stent with a gradient mesh density. Summary of the Invention
[0006] To address the issues raised in the background art, existing self-expanding intracranial thrombectomy stents, while capable of performing thrombectomy, suffer from limitations due to their fixed mesh density. This makes it difficult to balance the requirements for flexibility and embedding force at different sites: if a sparse mesh is used to achieve distal flexibility, the embedding force for hard thrombi in the middle of the stent is insufficient, leading to easy slippage during retraction; conversely, if a dense mesh is used to improve the middle capture force, the overall stiffness of the stent becomes excessive, making it difficult to reach the target lesion through tortuous vessels and resulting in poor compliance during retraction, leading to axial tensile deformation, reduced thrombus holding stability, and increased risk of thrombus fragmentation and escape. This invention provides a self-expanding intracranial thrombectomy stent with a gradually varying mesh density, comprising a delivery catheter with an inner guidewire slidably connected to its inner side, and a guidewire end located at the end of the inner guidewire away from the delivery catheter.
[0007] The inner guidewire is provided with three thrombectomy brackets: thrombectomy bracket one, thrombectomy bracket two, and thrombectomy bracket three, which are arranged sequentially along the axial direction.
[0008] A miniature fixing cylinder 1 is fixedly connected to the outer wall of the guide wire end, and a miniature fixing cylinder 2 is fixedly connected to the outer wall of the inner guide wire near the guide wire end; a thrombectomy bracket 4 is fixedly connected to the side of the miniature fixing cylinder 1 and the miniature fixing cylinder 2 that are close to each other.
[0009] An electrolytic wire is slidably fitted inside the delivery conduit, and an electrolytic ring is provided at one end of the miniature fixed cylinder away from the guide wire. The electrolytic wire and the electrolytic ring are connected to each other.
[0010] The inner side of the guidewire is provided with a liquid delivery conduit. The outer side of the liquid delivery conduit near the end of the guidewire is connected to multiple sets of drainage conduits. The multiple sets of drainage conduits are located on the inner side of the thrombectomy bracket.
[0011] Multiple sets of blocking guide wires are fixedly connected to one end of the miniature fixed cylinder one near the miniature fixed cylinder two, and the multiple sets of blocking guide wires are interconnected with the side wall of the miniature fixed cylinder two.
[0012] The thrombectomy stent 1, thrombectomy stent 2, and thrombectomy stent 3 are all made of superelastic shape memory nickel-titanium alloy, and are arranged from distal to proximal along the vascular axis. The mesh density of the thrombectomy stent 1 is less than that of the thrombectomy stent 2, and the mesh density of the thrombectomy stent 2 is less than that of the thrombectomy stent 3, forming an increasing gradient of sparse distal end and dense proximal end.
[0013] The electrolytic ring is made of a medical metal material that can undergo anodic dissolution under the action of an applied current. The micro-fixation cylinder one, micro-fixation cylinder two, thrombectomy stent four, and multiple sets of blocking guidewires are all made of medical biodegradable polymer materials. After the electrolytic wire energizes the electrolytic ring and causes it to corrode and melt, the micro-fixation cylinder one, micro-fixation cylinder two, thrombectomy stent four, and blocking guidewires can detach from the inner guidewire and remain in the blood vessel.
[0014] Both the delivery catheter and the drainage catheter are located inside the inner guidewire, and the spray nozzle of the drainage catheter is located inside the mesh of the thrombectomy stent four, so as to spray the thrombolytic drug solution through the mesh of the thrombectomy stent four towards the area where the thrombus is located.
[0015] When the electrolytic ring is not energized, the fourth thrombectomy stent and the inner guidewire remain linked, and the thrombus is pulled out by the fourth thrombectomy stent; after the electrolytic ring is energized and melts, the inner guidewire pulls the first thrombectomy stent to move the thrombus proximally, and the thrombus can avoid the outer side of the second miniature fixing cylinder and the electrolytic ring during the retraction process.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0017] 1. In this self-expanding intracranial thrombectomy stent with a gradually varying mesh density, the delivery catheter in a compressed state is pushed to the intracranial target lesion; positioning is achieved using the internal guidewire and its distal guidewire end; subsequently, the delivery catheter is withdrawn, causing thrombectomy stents one, two, three, and four to detach from constraint and self-expand within the lumen; among thrombectomy stents one, two, and three, the distal thrombectomy stent one has a sparse mesh, while the proximal thrombectomy stent three has a dense mesh, which is beneficial for the stent to adhere to the wall with distal flexibility after deployment and to generate strong initial encapsulation and embedding of hard thrombi with proximal dense mesh; the fluid delivery catheter inside the internal guidewire can spray thrombolytic drugs into the thrombus area through multiple sets of drainage catheters to cooperate with the main stent for physical softening.
[0018] 2. In this self-expanding intracranial thrombectomy stent with a gradually varying mesh density, after electrolytic disconnection, the guidewire continues to be pulled proximally. Thrombectomy stents located distally with appropriate mesh size are used to grasp the thrombus with the main pulling force. At this time, thrombectomy stent three, which is closest to the distal end and has the densest mesh, provides strong radial clamping and, together with thrombectomy stent one, stably holds the thrombus. Since the pulling direction and retraction path of thrombectomy stent one are directed towards the proximal delivery catheter, the thrombus moves proximally with thrombectomy stent one, thrombectomy stent two, and thrombectomy stent three, and can avoid the outer space of the micro-fixation cylinder two and the electrolytic ring, and is wrapped by the main stent system and withdrawn from the body. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention;
[0020] Figure 2 This is a schematic diagram of the delivery conduit of the present invention;
[0021] Figure 3 This is a schematic diagram of the structure of the thrombectomy bracket four of the present invention;
[0022] Figure 4 This is a schematic diagram of the electrolytic ring of the present invention;
[0023] Figure 5 This is a schematic diagram of the drainage conduit of the present invention;
[0024] Figure 6 This is a schematic diagram of the liquid delivery conduit of the present invention;
[0025] Figure 7 This is a schematic diagram of the internal guidewire of the present invention;
[0026] Figure 8 This is a schematic diagram of the structure of the miniature fixed cylinder II of the present invention.
[0027] The meanings of the labels in the diagram are as follows:
[0028] 1. Delivery catheter; 2. Inner guidewire; 3. Guidewire end; 4. Thrombus retrieval support one; 5. Thrombus retrieval support two; 6. Thrombus retrieval support three; 7. Miniature fixing tube one; 8. Miniature fixing tube two; 9. Thrombus retrieval support four; 11. Electrolytic wire; 12. Electrolytic ring; 13. Liquid delivery catheter; 14. Drainage catheter; 15. Blocking guidewire. Detailed Implementation
[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0030] Existing self-expanding intracranial thrombectomy stents can perform thrombectomy, but due to their fixed mesh density, they cannot meet the requirements of flexibility and embedment force for different sites. If a sparse mesh is used to pursue distal flexibility, the embedment force of the stent in the middle of the stent is insufficient for hard thrombi, and it is easy to slip out during withdrawal. If a dense mesh is used to improve the capture force in the middle, the overall stiffness of the stent is too large. It is not only difficult to reach the target lesion through tortuous vessels, but also has poor compliance during withdrawal, which easily causes axial tensile deformation, reduces the stability of thrombus clamping, and increases the risk of thrombus fragmentation and escape.
[0031] Therefore, this invention provides a self-expanding intracranial thrombectomy stent with a gradient mesh density, see [link to previous article]. Figures 1-8 As shown, it includes a delivery conduit 1, an inner guide wire 2 is slidably connected to the inner side of the delivery conduit 1, and a guide wire end 3 is provided at the end of the inner guide wire 2 away from the delivery conduit 1;
[0032] The inner guidewire 2 is provided with a thrombectomy bracket 4, a thrombectomy bracket 5 and a thrombectomy bracket 6 on the outer side wall near the guidewire end 3, and the three are arranged in sequence along the axial direction.
[0033] A miniature fixing cylinder 7 is fixedly connected to the outer wall of the guide wire end 3, and a miniature fixing cylinder 8 is fixedly connected to the outer wall of the inner guide wire 2 on the side close to the guide wire end 3; a thrombectomy bracket 4 9 is fixedly connected to the side of the miniature fixing cylinder 7 and the miniature fixing cylinder 8 that are close to each other.
[0034] An electrolytic wire 11 is slidably fitted inside the delivery conduit 1, and an electrolytic ring 12 is provided at the end of the miniature fixed cylinder 8 away from the guide wire end 3. The electrolytic wire 11 and the electrolytic ring 12 are connected to each other.
[0035] The inner guidewire 2 is provided with a liquid delivery conduit 13. The outer side of the liquid delivery conduit 13 near the guidewire end 3 is connected to multiple sets of drainage conduits 14. The multiple sets of drainage conduits 14 are located inside the thrombectomy bracket 9.
[0036] The miniature fixed cylinder 7 is fixedly connected to one end of the miniature fixed cylinder 8 with multiple sets of blocking guide wires 15, and the multiple sets of blocking guide wires 15 are connected to the side wall of the miniature fixed cylinder 8.
[0037] The thrombectomy stent 1 4, thrombectomy stent 2 5, and thrombectomy stent 3 6 are all made of superelastic shape memory nickel-titanium alloy, and are arranged along the vascular axis from distal to proximal. The mesh density of the thrombectomy stent 1 4 is less than that of the thrombectomy stent 2 5, and the mesh density of the thrombectomy stent 2 5 is less than that of the thrombectomy stent 3 6, forming an increasing gradient of sparse distal end and dense proximal end.
[0038] The electrolytic ring 12 is made of a medical metal material that can undergo anodic dissolution under the action of an applied current. The micro-fixation tube 1 7, micro-fixation tube 2 8, thrombectomy stent 4 9, and multiple sets of blocking guide wires 15 are all made of medical biodegradable polymer materials. After the electrolytic wire 11 energizes the electrolytic ring 12 to cause it to corrode and melt, the micro-fixation tube 1 7, micro-fixation tube 2 8, thrombectomy stent 4 9, and blocking guide wires 15 can detach from the inner guide wire 2 and remain in the blood vessel.
[0039] Both the delivery catheter 13 and the drainage catheter 14 are located inside the inner guidewire 2, and the spray nozzle of the drainage catheter 14 is located inside the mesh of the thrombectomy stent 9, so as to spray the thrombolytic drug solution through the mesh of the thrombectomy stent 9 to the area where the thrombus is located.
[0040] When the electrolytic ring 12 is not energized, the thrombectomy stent 4 9 is linked with the inner guidewire 2, and the thrombus is pulled out by the thrombectomy stent 4 9; after the electrolytic ring 12 is energized and melted, the inner guidewire 2 pulls the thrombectomy stent 4 to move the thrombus to the proximal end, and the thrombus can avoid the outer side of the miniature fixing cylinder 2 8 and the electrolytic ring 12 during the retraction process;
[0041] During operation, the compressed delivery catheter 1 is pushed to the intracranial target lesion; positioning is achieved using the internal guidewire 2 and its distal guidewire end 3; then the delivery catheter 1 is withdrawn, causing the thrombectomy stents 1-4, 2-5, 3-6, and 4-9 to detach from their constraints and self-expand within the lumen; among the thrombectomy stents 1-4, 2-5, and 3-6, the distal thrombectomy stent 1-4 has sparse mesh, while the proximal thrombectomy stent 3-6 has dense mesh, which is beneficial for the stents to adhere to the wall with distal flexibility after deployment, and to generate strong initial encapsulation and embedding of hard thrombi with proximal dense mesh; the fluid delivery catheter 13 inside the internal guidewire 2 can spray thrombolytic drugs into the thrombus area through multiple drainage catheters 14 to cooperate with the main stent for physical softening;
[0042] The overall device works together with bolt removal bracket 1 4, bolt removal bracket 2 5 and bolt removal bracket 3 6 to take into account the requirements of flexibility and clamping force for different parts.
[0043] When the operator decides not to use electrolytic separation based on the needs of the procedure, the electrolytic lead 11 and electrolytic ring 12 are kept in a non-energized connection state. At this time, the inner guidewire 2 is pulled proximally. Since the miniature fixation tube 1 7, miniature fixation tube 2 8 and thrombectomy stent 4 9 are all physically linked with the inner guidewire 2, the thrombectomy stent 4 9 can closely adhere to and hold the distal end of the thrombus. Thus, the thrombus is pulled by the thrombectomy stent 4 9, and the thrombus in the mesh is withdrawn together with the stent system into the delivery catheter 1 and extracted from the body. This mode is simple to operate and does not require triggering additional electrochemical operations.
[0044] When the operator determines that it is necessary to leave the micro-fixation tube 1 7, micro-fixation tube 2 8, and thrombectomy stent 4 9 in the blood vessel: First, current is applied to the electrolytic ring 12 through the electrolytic wire 11 in the delivery catheter 1, causing it to undergo electrochemical corrosion and melt; after melting, the linkage structure consisting of micro-fixation tube 1 7, micro-fixation tube 2 8, thrombectomy stent 4 9, and multiple sets of blocking guide wires 15 is disconnected and left in the blood vessel, and is subsequently gradually absorbed by the human body through biodegradable materials;
[0045] Meanwhile, after the electrolysis is disconnected, the inner guidewire 2 continues to be pulled proximally, and the thrombectomy stent 4, located distally with a suitable mesh size, is used to grasp the thrombus with the main pulling force. At this time, the thrombectomy stent 6, which is close to the distal end and has the densest mesh size, provides strong radial clamping and, together with the thrombectomy stent 4, stably holds the thrombus. Since the pulling direction and retraction path of the thrombectomy stent 4 are directed towards the proximal delivery catheter 1, the thrombus moves proximally with the thrombectomy stent 4, the thrombectomy stent 5, and the thrombectomy stent 6, and can avoid the outer space of the micro-fixation tube 2 8 and the electrolysis ring 12, and is wrapped by the main stent system and withdrawn from the body.
[0046] In summary, this approach effectively addresses the shortcomings of existing self-expanding intracranial thrombectomy stents. While they can perform thrombectomy, their fixed mesh density makes it difficult to balance the requirements for flexibility and embedding force at different sites. If a sparse mesh is used to achieve distal flexibility, the embedding force of the stent in the middle of the stent is insufficient for hard thrombi, making it prone to slippage during withdrawal. If a dense mesh is used to improve the capture force in the middle, the overall stiffness of the stent is too high, making it difficult to reach the target lesion through tortuous vessels. Furthermore, it exhibits poor compliance during withdrawal, easily leading to axial tensile deformation, reducing the stability of thrombus clamping, and increasing the risk of thrombus fragmentation and escape.
[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A self-expanding intracranial thrombectomy stent with a gradient mesh density, comprising a delivery catheter (1), characterized in that: The delivery conduit (1) is slidably connected to an inner guide wire (2), and the inner guide wire (2) is provided with a guide wire end (3) at the end away from the delivery conduit (1).
2. The self-expanding intracranial thrombectomy stent with gradient mesh density according to claim 1, characterized in that: The inner guidewire (2) is provided with a thrombectomy bracket 1 (4), a thrombectomy bracket 2 (5) and a thrombectomy bracket 3 (6) on the outer side wall near the guidewire end (3), and the three are arranged in sequence along the axial direction.
3. The self-expanding intracranial thrombectomy stent with gradient mesh density according to claim 1, characterized in that: The outer wall of the guide wire end (3) is fixed with a miniature fixing cylinder one (7), and the outer wall of the inner guide wire (2) is fixed with a miniature fixing cylinder two (8) on the side close to the guide wire end (3); the miniature fixing cylinder one (7) and the miniature fixing cylinder two (8) are both fixed with a thrombectomy bracket four (9) on the side close to each other.
4. The self-expanding intracranial thrombectomy stent with gradient mesh density according to claim 3, characterized in that: An electrolytic wire (11) is slidably fitted inside the delivery conduit (1), and an electrolytic ring (12) is provided at one end of the miniature fixed cylinder (8) away from the guide wire end (3). The electrolytic wire (11) and the electrolytic ring (12) are connected to each other.
5. A self-expanding intracranial thrombectomy stent with a gradient mesh density according to claim 3, characterized in that: The inner guidewire (2) is provided with a liquid delivery conduit (13). The outer side of the liquid delivery conduit (13) near the guidewire end (3) is connected to multiple sets of drainage conduits (14). The multiple sets of drainage conduits (14) are located inside the thrombectomy bracket (9).
6. A self-expanding intracranial thrombectomy stent with a gradient mesh density according to claim 3, characterized in that: Multiple sets of blocking guide wires (15) are fixed to one end of the micro-fixed cylinder one (7) near the micro-fixed cylinder two (8), and the multiple sets of blocking guide wires (15) are connected to the side wall of the micro-fixed cylinder two (8).
7. A self-expanding intracranial thrombectomy stent with a gradient mesh density according to claim 2, characterized in that: The thrombectomy stents 1 (4), 2 (5), and 3 (6) are all made of superelastic shape memory nickel-titanium alloy. Along the vascular axis from distal to proximal, the mesh density of the thrombectomy stent 1 (4) is less than that of the thrombectomy stent 2 (5), and the mesh density of the thrombectomy stent 2 (5) is less than that of the thrombectomy stent 3 (6), forming an increasing gradient of sparse distal and dense proximal.
8. A self-expanding intracranial thrombectomy stent with a gradient mesh density according to claim 3, characterized in that: The electrolytic ring (12) is made of medical metal material that can undergo anodic dissolution under the action of an applied current. The micro-fixation tube one (7), micro-fixation tube two (8), thrombectomy stent four (9) and multiple sets of blocking guide wires (15) are all made of medical biodegradable polymer material. After the electrolytic wire (11) energizes the electrolytic ring (12) to cause it to corrode and melt, the micro-fixation tube one (7), micro-fixation tube two (8), thrombectomy stent four (9) and blocking guide wires (15) can be detached from the inner guide wire (2) and left in the blood vessel.
9. A self-expanding intracranial thrombectomy stent with a gradient mesh density according to claim 5, characterized in that: Both the delivery catheter (13) and the drainage catheter (14) are located inside the inner guidewire (2), and the spray port of the drainage catheter (14) is located inside the mesh of the thrombectomy stent (9) so that the thrombolytic drug solution can be sprayed through the mesh of the thrombectomy stent (9) to the area where the thrombus is located.
10. A self-expanding intracranial thrombectomy stent with a gradient mesh density according to claim 3, characterized in that: When the electrolytic ring (12) is not energized, the thrombectomy bracket four (9) and the inner guide wire (2) remain linked and the thrombus is pulled out by the thrombectomy bracket four (9); after the electrolytic ring (12) is energized and melted, the inner guide wire (2) pulls the thrombectomy bracket one (4) to drive the thrombus to move proximally, and the thrombus can avoid the outer side of the miniature fixing tube two (8) and the electrolytic ring (12) during the retraction process.