A self-expanding biological thrombectomy stent and its demonstration method

Abstract

This invention provides a self-expanding bio-thrombectomy stent and its demonstration method, comprising: a push rod, a self-expanding polymer unit, a delivery sheath, and an elastic end; the demonstration method is as follows: First step: establish an intravascular access system; Second step: deliver the thrombectomy stent through the intravascular access system to the thrombus location; Third step: detach or slide the delivery sheath relative to its position, causing the self-expanding polymer unit to gradually expand and adhere to the vessel wall; Fourth step: retract the thrombectomy stent, withdrawing the thrombus from the body through a microcatheter or intermediate catheter, achieving the purpose of thrombus removal. Advantages of this invention: The stent of this invention has a strong ability to capture various types of thrombi, and the risk of thrombus escape after capture is low; it causes minimal damage to blood vessels, which is more conducive to improving the stent's adherence to the vessel wall; the stent is fully radiopaque, and the release point is easy to locate; it uses biodegradable materials and is non-toxic, non-corrosive, and has no coagulation effect.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a self-expanding biological thrombectomy stent and its demonstration method. Background Technology

[0002] Acute ischemic stroke (AIS) is a cerebrovascular disease caused by thrombus blockage of cerebral blood vessels, leading to abnormal local blood circulation in the brain tissue, resulting in the death of a large number of brain cells and endangering human life. Since drug thrombolysis has many limitations, such as its unsuitability for large-volume, rigid blood vessels, mechanical thrombectomy (or with added aspiration) has become the main treatment method. However, the thrombectomy stents currently used in mechanical thrombectomy mainly employ three-dimensional hollow metal structures, which have drawbacks during operation, including a high probability of thrombus escape, significant vascular damage, difficulty in locating the stent deployment point, and prolonged intraoperative time due to multiple thrombectomies. Therefore, there is an urgent need to develop a novel thrombectomy stent and its demonstration method. Summary of the Invention

[0003] The purpose of this invention is to provide a self-expanding bio-thrombectomy stent made of biodegradable polymer material and a demonstration method thereof, thereby improving the ability to capture thrombi and reducing damage to blood vessels.

[0004] To achieve the objective of this invention, the technical solution provided by this invention is as follows: a self-expanding bio-thrombectomy stent, comprising: a push rod, a self-expanding polymer unit disposed on the push rod, a delivery sheath detachably sleeved on the outside of the push rod and capable of at least partially covering the self-expanding polymer unit, and an elastic end located at the end of the push rod, wherein the self-expanding polymer unit automatically expands radially and releases when detached from the coverage of the delivery sheath.

[0005] Based on the above technical solution, the following supplementary technical solutions are further included:

[0006] Preferably, the outer diameter of the push rod is 0.2-0.6mm, the length is 1600-2000mm, the material is nickel-titanium alloy, and the surface has a PTFE coating to ensure reliable operation.

[0007] Preferably, the distal end of the push rod is connected to the elastic end, and the elastic end is a spring structure with a pitch of 0.036-0.082mm, a spring length of 3-30mm, a spring wire diameter of 0.035-0.080mm, and the spring wire material is platinum-tungsten or platinum-iridium alloy to ensure intravascular push.

[0008] Preferably, the push rod has at least two marking points, one of which is located between one side of the self-expanding polymer unit and the elastic end, and the other marking point is located on the other side of the self-expanding polymer unit, with a marking point length of 10-100 mm. This ensures reliable pushing.

[0009] Preferably, the self-expanding polymer unit is a sponge-like elastomer made of biodegradable polymer material that expands without external pressure. The material is chitosan, gelatin, or polylactic acid. A developer is added during the preparation of the self-expanding polymer unit; specifically, the developer may be barium sulfate, tantalum powder, or bismuth oxychloride, etc., to achieve whole-body development of the self-expanding polymer unit.

[0010] Preferably, the outer diameter of the self-expanding polymer unit after self-expansion is 3-7mm, the length is 5-30mm, the number is 1-4, and the shape is preferably cylindrical to achieve the fit of the blood vessel.

[0011] Preferably, the inner diameter of the delivery sheath is 0.20-0.65 mm, the outer diameter is 0.22-0.67 mm, and the length is 1500-2000 mm. The elastic end is a polymer tubular material covering structure with an inner diameter of 0.21-0.7 mm and an outer diameter of 0.22-0.8 mm. The material is polyurethane, polyetheramide, polyamide, polypropylene, or polyacrylonitrile.

[0012] Preferably, the delivery sheath is detachably detachable or slides relative to the push rod in an axial direction to trigger the self-expanding of the self-expanding polymer unit.

[0013] The second technical solution provided by this invention: a demonstration method for a self-expanding biological thrombectomy stent, comprising:

[0014] Step 1: Establishing an intravascular access system;

[0015] Step 2: The thrombectomy stent is inserted through the intravascular access system to reach the thrombus location;

[0016] Step 3: Tear off the delivery sheath or move the delivery sheath relative to the push rod, and the self-expanding polymer unit gradually expands and adheres to the inner wall of the blood vessel;

[0017] Step 4: Retract the stent. The thrombus is withdrawn from the body through a microcatheter or intermediate catheter, and the thrombus is removed until the procedure is complete.

[0018] Preferably, the blood vessels and thrombi are simulated demonstrators, which can be plastic, paper, or wooden models, or electronic virtual demonstration models, for teaching or publicity purposes.

[0019] Compared with the prior art, the present invention has the following positive effects: the thrombectomy stent of the present invention has a strong ability to capture various types of thrombi, and the risk of thrombus escape after capture is small; the thrombectomy stent of the present invention causes less damage to blood vessels, which is more conducive to improving the stent's apposition to the vessel wall; the thrombectomy stent of the present invention is radiopaque and the release point is easy to locate; the thrombectomy stent of the present invention is made of biodegradable material and is non-toxic, non-corrosive, and has no coagulation effect. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure when the material is not released in this invention;

[0022] Figure 2 This is a schematic diagram of the structure during release in this invention;

[0023] Figure 3 This is a first structural diagram of the self-expanding polymer unit in this invention;

[0024] Figure 4 for Figure 3 A schematic diagram of the cross-section along line AA;

[0025] Figure 5 This is a second structural diagram of the self-expanding polymer unit in this invention;

[0026] Figure 6 This is a third structural diagram of the self-expanding polymer unit in this invention;

[0027] Figure 7 This is a first structural diagram of the conveying sheath and the push rod in this invention;

[0028] Figure 8 for Figure 7 Schematic diagram of the cross section along line BB;

[0029] Figure 9 This is a second structural diagram of the conveying sheath and the push rod in this invention;

[0030] Figure 10 for Figure 9 A schematic diagram of the cross-section along line CC;

[0031] Figure 11 This is a schematic diagram of the first structure of the elastic end in this invention;

[0032] Figure 12 This is a schematic diagram of the second structure of the elastic end in this invention;

[0033] Figure 13 This is a schematic diagram of the marking points in this invention.

[0034] Figure 14 This is a schematic diagram of the thrombectomy process when the present invention is in the first position;

[0035] Figure 15This is a schematic diagram of the thrombectomy process when the present invention is in the second position;

[0036] Figure 16 This is a schematic diagram of the thrombectomy process when the present invention is in the third position;

[0037] Figure 17 This is a schematic diagram of the thrombectomy process when the present invention is in the fourth position;

[0038] Figure 18 This is a schematic diagram of the thrombectomy process when the present invention is in the fifth position;

[0039] Figure 19 This is a schematic diagram of the thrombectomy process when the present invention is in the sixth position. Detailed Implementation

[0040] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0041] For ease of description, the following description uses the terms "proximal" and "distal," where "distal" refers to the side of the instrument that is furthest from the operator when it is being delivered into the patient during normal use, from the physician's perspective; and "proximal" refers to the other side of the instrument.

[0042] like Figure 1-13 As shown, the present invention provides a first embodiment of a self-expanding biological thrombectomy stent. The thrombectomy stent 80 includes a push rod 100, a delivery sheath 300 detachably sleeved on the outside of the push rod 100 and capable of at least partially covering the self-expanding polymer unit, and an elastic end 400 located at the end of the push rod 100. Figure 1 As shown, when the delivery sheath 300 is wrapped around the self-expanding polymer unit, the self-expanding polymer unit is compressed within the lumen of the delivery sheath 300. At this time, the self-expanding polymer unit does not expand and is bound within the delivery sheath 300, which facilitates the delivery of the thrombectomy stent 80 from the puncture site of the blood vessel 20 to the lesion site.

[0043] like Figure 2-4 As shown, when the delivery sheath 300 is not covered by the self-expanding polymer unit, the self-expanding polymer unit will automatically expand and adhere to the wall of the blood vessel 20, forming a radial blockage, which facilitates the push of the thrombus 10 from the distal end to the outside of the body. In this embodiment, the shape of the self-expanding polymer unit after expansion is preferably cylindrical, including a first self-expanding polymer unit 210, a second self-expanding polymer unit 220, and a third self-expanding polymer unit 230. The diameter and height of the three are different.

[0044] like Figure 5-6As shown, the self-expanding polymer unit can be toothed, truncated cone, or spherical, including a fourth self-expanding polymer unit 240 in the form of a toothed shape, a fifth self-expanding polymer unit 250, a sixth self-expanding polymer unit 260, a seventh self-expanding polymer unit 270, an eighth self-expanding polymer unit 280, and a ninth self-expanding polymer unit 290 in the form of a truncated cone. Figure 5 As shown, two self-expanding polymer units are connected in series on the push rod 100, or as shown in the diagram. Figure 6 As shown, four self-expanding polymer units are connected in series on the push rod 100. The outer diameter of the self-expanding polymer unit after expansion is 3-7 mm, the length is 5-30 mm, and the number is 1-4. Preferably, the outer diameter of the self-expanding polymer unit after expansion is 5-30 times the outer diameter before expansion.

[0045] like Figure 7-10 As shown, the delivery sheath 300 is a radially heat-shrinkable tubing, which is heat-shrinkable onto the push rod 100, and self-expanding polymer units are pressed onto the push rod 100. The delivery sheath 300 also has a tear-away property; when the thrombectomy stent 80 reaches the lesion site, the delivery sheath 300 is torn off from the tear 320 near the proximal end of the thrombectomy stent 80, thus releasing the thrombectomy stent 80. The diameter of the push rod 100 is preferably 0.39 mm, and the length is preferably 1840 mm. The outer diameter of the heat-shrinkable delivery sheath 300 is preferably 0.45 mm, and the length is preferably 1800 mm. Figure 9-10 As shown, the delivery sheath 300 and the push rod 100 can slide relative to each other due to the gap 340. When the delivery sheath 300 slides towards the proximal end, the self-expanding polymer unit is released from the restraints within the delivery sheath 300 cavity, thereby releasing the thrombectomy bracket 80. The diameter of the push rod 100 is preferably 0.39 mm, and the length is preferably 1840 mm. The inner diameter of the delivery sheath 300 is preferably 0.48 mm, and the length is preferably 1600 mm.

[0046] like Figure 11 As shown, the elastic end 400 is a coiled spring structure 410. The spring wire diameter is preferably 0.058 mm, the pitch is preferably 0.063 mm, the spring length is preferably 30 mm, and the material is preferably platinum-tungsten or platinum-iridium alloy. The diameter of the push rod 100 is preferably 0.39 mm. The distal end 30 mm is ground to a diameter of 0.1 mm, and then the 30 mm ground nickel-titanium wire is inserted into the coiled spring structure 410 and fixed by adhesive or welding. The coiled spring structure 410 of the elastic end 400 can effectively ensure the flexibility of the tip of the thrombectomy stent 80, thereby avoiding damage to the blood vessel, and at the same time, it has good guidance and facilitates passage through tortuous blood vessels. Figure 12As shown, the elastic end 400 is a polymer tubular structure 420 covering the push rod 100. The polymer tubular structure 420 is attached to the push rod 100 by melting and molding to ensure the flexibility of the distal end of the support. The polymer tubular structure 420 can be made of materials such as polyurethane, polyetheramide, polyamide, polypropylene, and polyacrylonitrile.

[0047] Figure 13 The diagram shows the marking points. Marking points 101, 102, and 103 are used by doctors to predict the location of the thrombectomy stent within the blood vessel 20, indicating its imminent arrival at the lesion site. One marking point 101 is located between one side of the self-expanding polymer unit and the elastic end 400, while another marking point 102 is located on the other side of the self-expanding polymer unit, with a marking point length of 10-100mm. There are three ways to implement the marking points, as follows: First, position D on the push rod 100 is without PTFE coating, and position E on the push rod 100 is with PTFE coating; Second, position D on the push rod 100 is with PTFE coating, and position E on the push rod 100 is without PTFE coating; Third, position D is without coating or polymer tubular material, and position E is with coating or polymer tubular material.

[0048] like Figure 14-19 As shown, based on the thrombectomy stent 80 of the first embodiment, the present invention further provides a second embodiment of a demonstration method for a self-expanding biological thrombectomy stent, which includes the following steps:

[0049] Step 1: Establish the access system within the blood vessel 20, which includes establishing the access between the guiding catheter 50, the intermediate catheter 60, and the microcatheter 70. This access system is existing technology and will not be described in detail.

[0050] Step 2: The thrombectomy stent 80 is delivered through the intravascular access system 20 to the location of the thrombus 10;

[0051] Step 3: Tear off or move the relative position of the delivery sheath 300, and the self-expanding polymer unit gradually expands and adheres to the inner wall of the blood vessel 20.

[0052] Step 4: Withdraw the thrombectomy stent 80. The self-expanding polymer unit will pull the thrombus 10 out of the body through the microcatheter 70 or the intermediate catheter 60, thereby achieving the purpose of removing the thrombus 10.

[0053] Thrombus 10 and Blood Vessel 20 are both simulation demonstrations, which can be plastic, paper or wood models, or electronic virtual demonstration models or software display models, to achieve teaching or publicity demonstrations.

[0054] The advantages of this invention are: the thrombectomy stent of this invention has a strong ability to capture various types of thrombi, and the risk of thrombus escape after capture is small; the thrombectomy stent causes less damage to blood vessels, which is more conducive to improving the apposition of the thrombectomy stent to the vessel wall; the thrombectomy stent of this invention is radiopaque throughout, and the release point is easy to locate; the thrombectomy stent of this invention is made of biodegradable material and is non-toxic, non-corrosive, and has no coagulation effect.

[0055] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications and improvements made by those skilled in the art without departing from the inventive concept of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A self-expanding biological thrombectomy stent, characterized in that... It includes: The device comprises a push rod (100), a self-expanding polymer unit disposed on the push rod (100), a delivery sheath (300) detachably sleeved on the outside of the push rod (100) and capable of at least partially covering the self-expanding polymer unit, and an elastic end (400) located at the end of the push rod (100). When the delivery sheath (300) covers the self-expanding polymer unit, the self-expanding polymer unit is pressed into the inner cavity of the delivery sheath (300). When the self-expanding polymer unit is detached from the coverage of the delivery sheath (300), it automatically expands radially and releases, adhering to the wall of the blood vessel. The self-expanding polymer unit is a sponge-like elastomer made of biodegradable polymer material and self-expanding without external force.

2. The self-expanding biological thrombectomy stent according to claim 1, characterized in that: The push rod (100) has an outer diameter of 0.2-0.6 mm, a length of 1600-2000 mm, and is made of nickel-titanium alloy.

3. The self-expanding biological thrombectomy stent according to claim 1, characterized in that: The far end of the push rod (100) is connected to the elastic end (400), and the elastic end (400) is a spring structure with a pitch of 0.036-0.082mm, a spring length of 3-30mm, a spring wire diameter of 0.035-0.080mm, and the spring wire material is platinum-tungsten or platinum-iridium alloy.

4. The self-expanding biological thrombectomy stent according to claim 3, characterized in that: The push rod (100) has at least two marking points (101, 102, 103), one of which (101) is located between one side of the self-expanding polymer unit and the elastic end (400), while the other marking point (102) is located on the other side of the self-expanding polymer unit, and the length of the marking point is 10-100mm.

5. The self-expanding biological thrombectomy stent according to claim 1, characterized in that, The materials are chitosan, gelatin, and polylactic acid.

6. The self-expanding biological thrombectomy stent according to claim 1, 2, 3, 4, or 5, characterized in that, The self-expanding polymer unit has an outer diameter of 3-7 mm, a length of 5-30 mm, and a quantity of 1-4 units after self-expansion.

7. The self-expanding bio-thrombectomy stent according to claim 1, 2, or 5, characterized in that, The inner diameter of the delivery sheath (300) is 0.20-0.65 mm, the outer diameter is 0.22-0.67 mm, and the length is 1500-2000 mm. The elastic end (400) is a polymer tubular material covering structure with an inner diameter of 0.21-0.7 mm and an outer diameter of 0.22-0.8 mm. The material is polyurethane, polyetheramide, polyamide, polypropylene, or polyacrylonitrile.

8. The self-expanding biological thrombectomy stent according to claim 1, 2, 3, 4, or 5, characterized in that, The delivery sheath (300) can be detachably torn off or slide relative to the push rod (100) in an axial direction.

9. The self-expanding biological thrombectomy stent according to claim 6, characterized in that, The outer diameter of the self-expanding polymer unit after self-expansion is 5-30 times that before self-expansion.

10. A demonstration method using the thrombectomy stent as described in claim 1, 2, 3, 4, or 5, characterized in that... Includes the following steps: Step 1: Construct a pathway system within a blood vessel, where the blood vessel is a simulated demonstrator; Step 2: The thrombectomy stent (80) is passed through the intravascular access system to reach the thrombus location, wherein the thrombus is a simulated demolition object; Step 3: Tear off the delivery sheath (300) or move the delivery sheath (300) relative to the push rod, and the self-expanding polymer unit gradually expands and adheres to the inner wall of the blood vessel; Step 4: Retract the stent. The thrombus is withdrawn from the body through a microcatheter or intermediate catheter, and the thrombus is removed until the procedure is complete.

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