Recyclable intracranial arterial stent system

Abstract

The application discloses a recyclable intracranial artery stent system and belongs to the technical field of medical auxiliary instruments. The recyclable intracranial artery stent system comprises a stent and a recycling device. The stent comprises a stent body and a recyclable joint arranged at the proximal end of the stent body. The recycling device comprises a recycling catheter, a push rod and a recycling cage. The push rod is arranged inside the recycling catheter and can slide in the recycling catheter. The recycling cage is connected to the distal end of the push rod and can grasp the joint for recycling. The recyclable intracranial artery stent system can relieve intracranial artery stenosis in a short period, repair the vascular lumen structure, and take out the stent from the body after the intracranial artery lumen structure is repaired and stabilized, thereby avoiding long-term retention of the stent and effectively reducing the loss of the effective lumen of the intracranial artery. The stent can be recycled and replaced according to the recovery of the blood vessel and the stent fitting degree, the treatment scheme can be adjusted in the subsequent period, the problem of in-stent restenosis is solved, and the treatment effect of patients with intracranial artery stenosis is ensured.

Description

Technical Field

[0001] This invention relates to the field of medical assistive device technology, and in particular to a retrievable intracranial arterial stent system. Background Technology

[0002] Ischemic cerebrovascular disease refers to intracranial artery occlusion or embolism. The main cause of intracranial artery occlusion is intracranial artery stenosis. Currently, the main types of stents used to treat intracranial artery stenosis include the Wingspan stent (Boston Scientific, USA), the Apollo stent (Shanghai MicroPort Technology Co., Ltd.), and the Solitaire stent system (Johnson & Johnson, USA), all of which are non-retrievable stent systems after deployment. In such cases, once the stent is implanted, it cannot be removed, and repeated stent implantation in the same lesion area is not advisable. Due to the limited diameter of intracranial arteries, if restenosis occurs in the stent implantation area, further stent implantation is not recommended, as the stent may even stimulate excessive endothelial proliferation or thrombosis, leading to intracranial vascular occlusion. The purpose of this invention is to solve this problem.

[0003] The existing Wingspan stent system is a self-expanding stent system with an open-loop design. It has good vascular compliance, can easily navigate the tortuous and angled shapes of intracranial vessels, and can readily reach the lesion site while conforming well to the vessel wall. Its disadvantages include complex operation, high requirements for the condition of the lesion site and distal vessels, and reduced adaptability.

[0004] The Apollo stent system is a pre-positioned balloon-expandable stent. Its advantages include simple operation and accurate positioning. However, its disadvantages include poor vascular permeability, making it difficult to pass through tortuous intracranial vessels, and a high failure rate. The Solitaire stent system is a retrievable stent system. One end is placed in a blood vessel, and the other end has an operating lever. During use, the stent is guided into the blood vessel and released to capture any blood clots. The stent is then pulled back using the operating lever to retrieve it, during which time the blood clots are captured. However, this stent only serves a capture function and is not left in the body. Existing stents do not have the capability to remain in the body for several days before retrieval.

[0005] All three have in common that once implanted in the body, they cannot be retrieved. Summary of the Invention

[0006] This invention provides a retrievable intracranial arterial stent system to solve the technical problem that existing stents cannot be left in the human body for several days before being retrieved.

[0007] The present invention adopts the following technical solution: a retrievable intracranial arterial stent system, comprising a stent and a retrieval device. The stent includes a stent body and a retrievable connector disposed at the proximal end of the stent body. The retrieval device includes a retrieval catheter, a push rod, and a retrieval cage. The push rod is located inside the retrieval catheter and can slide within the retrieval catheter. The retrieval cage is connected to the distal end of the push rod and passes through the retrieval catheter. The retrieval cage can grasp the connector for retrieval.

[0008] Furthermore, the stent body is a self-expanding closed-loop structure, which is composed of multiple closed-loop cells. Adjacent closed-loop cells are connected to each other through Z-shaped connectors, so that the stent can conform to the tortuous anatomy of the intracranial arteries and be successfully retrieved.

[0009] Furthermore, the Z-shaped connector is an elastic bending structure, which improves the flexibility and vascular permeability of the stent body, enabling the stent to adapt to tortuous intracranial blood vessels and facilitate retrieval.

[0010] Furthermore, the connector is a frustum connector, with one end being a smooth cone and the other end being a flat or concave base.

[0011] Furthermore, the bracket body and the base of the connector are connected by a connecting part with a length of 2-3mm.

[0012] Furthermore, the recycling cage is provided with a conical placement cylinder fixedly connected to the far end of the push rod. The inner wall of the conical placement cylinder is provided with at least three independent elastic claws. The at least three elastic claws are evenly distributed in the circumferential direction with the central axis of the push rod as a reference to form a conical surface.

[0013] Furthermore, one end of each elastic claw is fixedly connected to the inner wall of the conical placement cylinder, while the other end is a free end that extends obliquely toward the central axis of the push rod to form a conical surface.

[0014] Furthermore, the free end edge of the elastic claw is provided with a rounded corner blunting structure.

[0015] Furthermore, the recycling cage is made of flexible material, while the conical placement cylinder is made of rigid material.

[0016] Furthermore, the length of the retrieval tube is 150-160cm, the length of the push rod is 155-165cm, and the length of the retrieval cage is 4-6mm.

[0017] Preferably, the length of the recovery conduit is 155cm, the length of the push rod is 160cm, and the length of the recovery cage is 5mm.

[0018] Furthermore, the diameter of the unfolded bracket can be 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm or 5.0mm.

[0019] It should be noted that the stent can be pre-placed in the stent catheter and then delivered to the lesion site for stent implantation through the stent catheter.

[0020] The above-described at least one technical solution adopted in the embodiments of the present invention can achieve the following beneficial effects: This invention can relieve intracranial arterial stenosis in a short period of time and repair the vascular lumen structure. After the intracranial arterial lumen structure is repaired and stabilized, the stent can be removed from the body, avoiding long-term stent retention and thus effectively reducing the loss of effective lumen of the intracranial arteries. Due to the retrievable design of the stent, it can be reused repeatedly in the same lesion area. The stent can also be retrieved and replaced according to the recovery of the blood vessels and the stent fit, which facilitates subsequent adjustment of the treatment plan and solves the problem of in-stent restenosis, thereby ensuring the treatment effect for patients with intracranial arterial stenosis. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 2 ; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the bracket not being grasped in this invention; Figure 5 for Figure 4 Sectional view along the BB line; Figure 6 This is a schematic diagram of the gripping bracket in this invention; Figure 7 for Figure 6 A cross-sectional view along the CC line; Figure 8 This is a three-dimensional structural diagram of the recycling device in this invention; Figure 9 This is a three-dimensional structural breakdown diagram of the recycling device in this invention.

[0022] Figure Labels Support 1, support body 10, connector 11, closed-loop cell 12, Z-shaped connector 13, connector 14, recycling device 2, recycling conduit 20, push rod 21, recycling cage 22, conical placement cylinder 3, elastic claw 30. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] The following is in conjunction with the appendix Figure 1-9 The technical solutions provided by the various embodiments of the present invention are described in detail below.

[0025] This invention provides a retrievable intracranial arterial stent system, including a stent 1 and a retrieval device 2. The stent 1 includes a stent body 10 and a retrievable connector 11 disposed proximal to the stent body 10. The retrieval device 2 includes a retrieval catheter 20, a push rod 21, and a retrieval cage 22. The push rod 21 is located inside the retrieval catheter 20 and can slide within the retrieval catheter 20. The retrieval cage 22 is connected to the distal end of the push rod 21 and passes through the retrieval catheter 22. The retrieval cage 22 can grasp the connector 11 for retrieval.

[0026] Working principle: First, the stent 1 is pre-placed in the stent catheter, and the compressed stent body 10 is precisely delivered to the stenotic site of the intracranial artery lesion through the stent catheter; after reaching the target position, the stent 1 is released, and the stent body 10 unfolds and fits the diseased blood vessel wall by its own structural characteristics, so as to effectively support the stenotic blood vessel and restore intracranial blood flow. When stent 1 needs to be retrieved, such as in cases of stent positioning deviation, postoperative adverse reactions, or stent replacement, the retrieval device 2 is operated: the push rod 21 is pushed to slide inside the retrieval catheter 20, so that the retrieval cage 22 connected to the distal end of the push rod 21 reaches the connector 11 at the proximal end of the stent body 10. The connector 11 can smoothly enter the conical placement cylinder 3 along the conical guide surface formed by the elastic claw 30, thereby grasping the connector 11. Then, the push rod 21 is pulled in the opposite direction to gradually pull the stent back into the retrieval catheter 20, completing the entire retrieval process. During the retrieval process, additional damage to intracranial blood vessels can be avoided.

[0027] The retrieval device 2 can quickly and accurately grab and retrieve the connector 11 of the stent 1, effectively compensating for positioning errors during the surgical procedure, reducing the surgical failure rate caused by improper stent implantation, and improving surgical safety.

[0028] With its recyclable design, the stent can be retrieved after implantation based on vascular recovery and stent fit, facilitating subsequent adjustments to the treatment plan, avoiding the aforementioned risks, and significantly improving the flexibility and safety of treatment.

[0029] It should be noted that after a stent is implanted into a blood vessel, vascular endothelial cells can gradually migrate, proliferate, and cover the stent along its surface, achieving stent endothelialization. Endothelialization is a dynamic process, typically divided into three stages: Acute phase (hours to 2 days): A thrombus layer forms on the surface of the stent. At this time, the bond between the stent and the blood vessel wall is extremely weak, making removal the easiest, but the risk of blood vessel damage is high and thrombotic complications are likely to occur.

[0030] Repair period (3 days to 3 weeks): Endothelial cells begin to migrate and proliferate, forming "islands" that cover the scaffold mesh. This is the optimal time window for scaffold removal. At this time, the endothelial layer is still discontinuous, and intercellular junctions (such as tight junctions) have not yet fully formed. There is still a separable physical interface between the scaffold and the vessel wall.

[0031] Maturation stage (>1 month): Endothelial cells completely cover the scaffold, smooth muscle cells proliferate, collagen is deposited, and the scaffold is "embedded" in the blood vessel wall, making it difficult to remove.

[0032] Therefore, stent retrieval needs to be performed within a safe timeframe, generally 7-14 days post-procedure, to precisely control the retrieval window before the endothelium excessively covers the stent body, thus avoiding vascular damage and thrombotic complications.

[0033] In this embodiment, refer to Figure 2 and Figure 3 As shown, the stent body 10 is a self-expanding closed-loop structure. The stent body 10 is composed of multiple closed-loop cells 12. Adjacent closed-loop cells 12 are connected to each other through Z-shaped connecting parts 13, so that the stent body 10 can conform to the tortuous anatomical structure of the intracranial artery and achieve smooth retrieval.

[0034] In this embodiment, the Z-shaped connecting part 13 is an elastic bending structure, which is used to improve the flexibility and blood vessel passage of the stent body 10, so that the stent body 10 can adapt to the tortuous blood vessels in the cranium and facilitate the retrieval operation.

[0035] When the stent body 10 is pre-placed in the stent catheter, it is in a compressed state. When it is delivered to the lesion and released, the stent body 10 automatically expands due to its self-expansion property. The closed-loop cell 12 can evenly conform to the blood vessel wall and provide stable support. The Z-shaped connector 13 is an elastic bending structure that can flexibly bend with the tortuous shape of the intracranial artery during the expansion of the stent body 10. At the same time, when the stent body 10 is retrieved, the Z-shaped structure can undergo elastic deformation, so that the stent body 10 can be smoothly compressed back into the retrieval catheter 20, avoiding retrieval jamming caused by blood vessel tortuosity or the retrieval catheter being too small.

[0036] The self-expanding closed-loop structure takes into account both the compliance of the open-loop stent body 10 and the stability of the closed-loop stent body 10. The elastic bending design of the Z-shaped connector 13 further improves the flexibility and vascular accessibility of the stent 10, enabling it to pass smoothly through tortuous intracranial blood vessels to reach the lesion site, and also allowing for flexible deformation during retrieval, reducing the difficulty of retrieval.

[0037] The design of the closed-loop cell 12, combined with the connecting function of the Z-shaped connector 13, makes the structure of the entire stent body 10 uniform in density, and the supporting force applied to the intracranial artery is more uniform. This avoids damage to the vascular endothelium caused by excessive local force, further prevents local restenosis of the intracranial artery stent, improves the treatment effect, and makes up for the defects of uneven support force of existing stents.

[0038] The Z-shaped connection method ensures that the entire support body 10 has good ductility during the stretching and recycling process, preventing the support body 10 from breaking due to excessive tensile stress during recycling, and ensuring the safety and integrity of the recycling process.

[0039] Furthermore, in order to reduce the diameter of the stent body 10 to a sufficiently small size during the retrieval process, the stent is preferably made of an alloy with low radial force and high elasticity (such as β-type titanium alloy), which significantly reduces stress concentration in the blood vessel wall, reduces excessive intimal proliferation, thereby reducing resistance during the retrieval process and avoiding damage to the blood vessel wall.

[0040] In this embodiment, the connector 11 is a frustum connector. One end of the frustum connector is a smooth cone to avoid scratching the blood vessel wall, and the other end of the frustum connector is a flat or concave base, preferably concave, to facilitate engagement with the elastic claw and prevent dislodgement. The aforementioned base is connected to the stent body 10 at one end via a connecting portion 14, which is 2-3 mm long. This connecting portion facilitates the entry of the frustum-shaped connector into the elastic claws 30, preventing the stent body 10 from blocking the elastic claws 30 and causing them to fail to reset, thus effectively securing the frustum-shaped connector. Furthermore, the connecting portion 14 is connected to all the connecting ribs proximal to the stent body 10 via its other end. Thus, when the connector 11 is retracted, the axial stretching of the connecting portion 14 causes the diameter of the stent body 10 to gradually decrease in the retraction direction, allowing the stent rod to "slide out" from the side of the endothelial cell layer instead of being "torn out" vertically, reducing damage to the endothelial cell layer of the blood vessel wall.

[0041] The base of the frustum connector is 0.5-1mm in size, which is larger than the opening size of the cone tip of the conical surface formed by the elastic claw 30, so that the elastic claw 30 can lock the base of the frustum connector.

[0042] In this embodiment, refer to Figure 8 and Figure 9 As shown, the recycling cage 22 is provided with a conical placement cylinder 3 that is fixedly connected to the far end of the push rod 21. The inner wall of the conical placement cylinder 3 is provided with at least three independent elastic claws 30. The at least three elastic claws are evenly distributed in the circumferential direction with the central axis of the push rod 21 as the reference to form a conical surface.

[0043] It should be noted that the recycling cage 22 is made of flexible materials, such as silicone or expanded polytetrafluoroethylene, while the conical placement cylinder 3 is a rigid load-bearing structure, and its material can be polycarbonate, polysulfone, polyetheretherketone, polypropylene, etc.

[0044] The advantages of setting up a conical placement cylinder 3 are as follows: First, the recovery cage 22 is only an outer protective structure. To avoid damaging the blood vessel wall, a flexible material is used. The elastic claws 30 installed directly on the flexible material are unevenly stressed, and the flexible material cannot provide effective fixation and support strength for the elastic claws. When the elastic claws are squeezed, they cannot form a conical surface that matches the connector 11. The elastic claws 30 are difficult to be squeezed, deformed and reset smoothly. Therefore, a rigid conical placement cylinder 3 connected to the push rod 21 is set inside the recovery cage 22 to provide effective fixation and support strength for the elastic claws, so that the elastic claws can be squeezed, deformed and reset under the pressure of the connector 11, and the connector 11 can be effectively locked inside the conical placement cylinder 3. Secondly, during retrieval, the claws need to withstand the axial tension of the pull bracket. The retrieval cage 22 is a flexible structure and cannot withstand the gripping tension of the claws. If the claws are directly installed on the retrieval cage 22, it will cause them to loosen, deform the cage, and completely lose the retrieval function. However, the conical placement cylinder 3 connected to the push rod 21 is a rigid load-bearing structure and can directly transmit the tension to the push rod 21.

[0045] In this embodiment, one end of each elastic claw 30 is fixedly connected to the inner wall of the conical placement cylinder 3, and the other end is a free end that extends inward at an angle.

[0046] Furthermore, the free end edge of the elastic claw 30 is provided with a rounded corner blunting structure.

[0047] When stent 1 needs to be retrieved, medical staff operate the push rod 21, causing it to slide within the retrieval catheter 20, which in turn moves the retrieval cage 22 connected to the distal end of the push rod 21 towards the connector 11 proximal to the stent body 10. Because the elastic claws 30 extend inwards towards the conical placement cylinder 3, and multiple elastic claws 30 together form a conical surface that precisely matches the shape of the connector 11, the connector 11, pushed by the push rod 21, can smoothly enter the retrieval cage 22 along the conical guide surface formed by the elastic claws 30. As the connector 11 gradually penetrates deeper, its conical surface will... The claw 30 generates an outward squeezing force, causing the elastic claw 30 to undergo elastic deformation. When the connector 11 is fully inserted into the conical placement cylinder 3, the connector 11 no longer squeezes the elastic claw 30, and the elastic claw 30 returns to its original position. Thus, the free end of the elastic claw 30 abuts against the bottom plane of the frustum connector. Due to the obstruction of the elastic claw 30, the connector 11 cannot retract from the recovery cage 22, thus achieving the gripping of the connector 11. After the gripping is completed, the push rod 21 is pulled in the opposite direction, causing the support body 10 to be gradually compressed and enter the recovery conduit 20, completing the safe recovery of the support 1. Reference Figure 5 and Figure 7 As shown, Figure 5 This is a schematic diagram showing the connector 11 before it enters the conical placement cylinder 3. Figure 7 A schematic diagram showing the connector 11 being held in place by multiple elastic claws 30 inside the conical placement cylinder 3; After being recovered from the outside, one or more of the elastic claws 30 are pressed to deform them, exposing a gap, and the connector 11 is taken out from the conical placement cylinder 3.

[0048] The rounded corner blunting structure prevents the free end of the elastic claw 30 from cutting off the connecting part 14 during the entire recycling process, ensuring the safety of the recycling operation.

[0049] The elastic claws 30 are evenly distributed in a circumferential direction to form a conical surface that matches the shape of the connector 11. When the recovery cage 22 approaches the connector 11, the conical surface can play an automatic guiding role. Without the need for medical personnel to accurately align the connector 11, the connector 11 can be guided smoothly into the locking area, which greatly reduces the difficulty and accuracy requirements of the recovery operation.

[0050] In this embodiment, the length of the recovery conduit 20 is 155cm, and the length of the push rod 21 is 160cm. The push rod 21 is located inside the recovery conduit 20 and can slide. The length difference design ensures that the push rod 21 can push the recovery cage 22 out of the recovery conduit 20 to grasp the connector 11. The length of the recovery cage 22 is 5mm, which is adapted to the size of the connector 11 to ensure the stability of the grasp.

[0051] The length design of the retrieval catheter 20 and the push rod 21 is adapted to the operation path of intracranial artery surgery, ensuring that the push rod 21 can slide flexibly and drive the retrieval cage 22 to accurately reach the target position, avoiding operation jamming due to improper size.

[0052] In this embodiment, the diameter of the stent body 10 after deployment can be designed to be 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, or 5.0mm. The appropriate stent body 10 size can be selected according to the diameter of the blood vessel in the patient's intracranial arterial lesion area, ensuring that the stent body 10 can closely conform to the blood vessel wall after deployment, while avoiding vascular damage due to excessively large stent body 10 size or insufficient support due to excessively small size.

[0053] In this embodiment, the stent 1 can be pre-placed in the stent catheter and then delivered to the lesion through the stent catheter.

[0054] When in use, the above-mentioned stent catheter can be used as a rapid exchange catheter delivery system to further deliver stent 1 with precision. Two imaging points are set on the stent body, which can clearly show the position of the stent body under X-ray, making it easy for medical staff to accurately locate the stent and confirm whether the stent implantation position is accurate. At the same time, the length of the stent body after unfolding can be checked to ensure that the stent body completely covers the lesion area and meets the treatment needs.

[0055] The above are merely embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A retrievable intracranial arterial stent system, characterized in that, The device includes a support (1) and a retrieval device (2). The support (1) includes a support body (10) and a retrievable connector (11) located at the proximal end of the support body (10). The retrieval device (2) includes a retrieval conduit (20), a push rod (21), and a retrieval cage (22). The push rod (21) is located inside the retrieval conduit (20) and can slide inside the retrieval conduit (20). The retrieval cage (22) is connected to the distal end of the push rod (21) and passes through the retrieval conduit (22). The retrieval cage (22) can grab the connector (11) for retrieval.

2. The retrievable intracranial arterial stent system according to claim 1, characterized in that, The support body (10) is a self-expanding closed-loop structure. The support body (10) is composed of multiple closed-loop cells (12), and adjacent closed-loop cells (12) are connected to each other through Z-shaped connecting parts (13).

3. A retrievable intracranial arterial stent system according to claim 2, characterized in that, The Z-shaped connecting part (13) is an elastic bending structure.

4. A retrievable intracranial arterial stent system according to claim 1, characterized in that, The connector (11) is a frustum connector. One end of the frustum connector is a smooth head for entering the recycling cage (22), and the other end of the frustum connector is a flat or concave base for connecting with the support body (10).

5. A retrievable intracranial arterial stent system according to claim 4, characterized in that, The bracket body (10) and the base of the connector (11) are connected by a connecting part (14), the length of which is 2-3mm.

6. A retrievable intracranial arterial stent system according to claim 1, 4, or 5, characterized in that, The recycling cage (22) is provided with a conical placement cylinder (3) fixedly connected to the far end of the push rod (21). The inner wall of the conical placement cylinder (3) is provided with at least three independent elastic claws (30). The at least three elastic claws (30) are evenly distributed in the circumferential direction with the central axis of the push rod (21) as a reference to form a conical surface to guide the connector (11) into engagement.

7. A retrievable intracranial arterial stent system according to claim 6, characterized in that, One end of each elastic claw (30) is fixedly connected to the inner wall of the conical placement cylinder (3), and the other end is a free end that extends obliquely toward the central axis of the push rod (21) to form a conical surface.

8. A retrievable intracranial arterial stent system according to claim 7, characterized in that, The free end edge of the elastic claw (30) is provided with a rounded corner blunting structure.

9. A retrievable intracranial arterial stent system according to claim 6, characterized in that, The recycling cage (22) is made of flexible material, while the conical placement cylinder (3) is made of rigid material.

10. A retrievable intracranial arterial stent system according to claim 1, characterized in that, The length of the recovery conduit (20) is 150-160cm, the length of the push rod (21) is 155-165cm, and the length of the recovery cage (22) is 4-6mm.

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