Multi-section thrombectomy stent with variable outer diameter

Abstract

The invention provides a multi-section thrombectomy stent with a variable outer diameter, and relates to the technical field of interventional medical instruments. The multi-section thrombectomy stent comprises a stent body and a push rod connected with the stent body; the hollow pipe is arranged on the support body and connected with the push rod; wherein one part of the pushing rod is a cavity section, the cavity section comprises a fluid conveying channel, and the fluid conveying channel is communicated with an inner cavity of the hollow pipe and used for conveying fluid to the inner cavity of the hollow pipe so that the portion, connected with the hollow pipe, of the support body can be gradually expanded under the pressure of the fluid. Fluid is conveyed to the inner cavity of the hollow tube through the fluid conveying channel so that the far end of the second stent section can be in an expanded state, the second stent section can be better attached to the inner wall of a blood vessel, the capacity of grabbing thrombus in variable-diameter blood vessels and tortuous blood vessel sections is improved, the probability of thrombus disengagement in the recovery process is reduced, and the recovery efficiency is improved. And the adaptability of the second stent section and the inner wall of the blood vessel is higher.

Description

Technical Field

[0001] The present invention belongs to the technical field of interventional medical devices, and in particular relates to a multi-section thrombectomy stent with a variable outer diameter. Background Art

[0002] Ischemic stroke caused by blood clots in cerebral blood vessels is a difficult-to-treat disease that seriously endangers human health and life safety. The number of deaths from stroke in China each year has exceeded that of tumors and cardiovascular diseases, becoming the leading cause of death. In order to solve the above-mentioned problem of ischemic stroke deaths caused by blood clots, the method of mechanical thrombus removal has become a research hotspot in recent years.

[0003] Stent thrombectomy is a common way to mechanically remove thrombi. When performing stent thrombectomy, a guide catheter is first placed proximal to the location where the thrombus occurs through standard puncture techniques. Then a microcatheter is guided through a guide wire and sent from the guide catheter passage to the location of the thrombus and through the thrombus. Then, the guide wire in the microcatheter is withdrawn, and the thrombus retriever stent is introduced into the microcatheter through the sheath and along the inner lumen of the microcatheter to the location of the thrombus. The thrombus retriever stent is flush with the end of the microcatheter. Then, the microcatheter is withdrawn to expose the thrombus retriever stent in the thrombus. The thrombus retriever stent expands and fully embeds into the thrombus. Finally, the thrombus retriever stent is withdrawn into the guide catheter together with the microcatheter, and the thrombus is removed from the human body through the inner lumen of the guide catheter.

[0004] Currently, the thrombectomy stents on the market are mainly made of nickel-titanium hypotubes cut by laser. Generally speaking, the outer diameters of the thrombectomy stents are the same. For blood vessels with severe and tortuous diameter sections, choosing a thrombectomy stent with a larger outer diameter will cause wear and scratches on the blood vessel wall. Choosing a thrombectomy stent with a smaller outer diameter will have lower supporting force and poor wall adhesion, and is prone to unstable phenomena such as displacement, which will affect the effectiveness of the product and weaken its ability to capture blood clots. The blood clots can easily fall off the stent during the recovery process. Therefore, it is necessary to solve the problem of insufficient adaptability of existing thrombectomy stents to the inner walls of blood vessels with severe and tortuous diameter sections.

[0005] Therefore, there is a need to provide a new, more effective thrombectomy stent with a variable outer diameter. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-section thrombectomy stent with a variable outer diameter. A hollow tube whose size is controlled by a fluid delivery channel is provided. The hollow tube is tightly connected to the stent body, thereby driving the size of the connecting part to change, so as to better fit the inner wall of the blood vessel and improve the adaptability of the thrombectomy stent.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A multi-section thrombus removal stent with a variable outer diameter, comprising a stent body and a pushing rod connected to the stent body;

[0009] A hollow tube, provided on the support body and connected to the push rod;

[0010] Part of the push rod is a hollow section, and the hollow section includes a fluid delivery channel, which is connected to the inner cavity of the hollow tube and is used to deliver fluid to the inner cavity of the hollow tube so that the part where the stent body is connected to the hollow tube gradually expands under the pressure of the fluid;

[0011] In the radial direction, the size of the connection portion between the stent body and the hollow tube in a state where the fluid is not transported is smaller than the size of the connection portion between the stent body and the hollow tube in a state where the fluid is transported.

[0012] Preferably, the stent body comprises a plurality of mutually connected stent segments, a stent segment two whose distal end is connected to the stent segment one, the distal end of the stent segment two is connected to a hollow tube, and the proximal end of the stent segment two is connected to a push rod.

[0013] Preferably, the distal end of the hollow tube is connected to the circumference of the distal end of the second section of the stent in a threading manner and is closed to form a ring.

[0014] Preferably, a memory alloy wire is placed inside the hollow tube, and the outer contour of the memory alloy wire is adapted to the outer contour of the distal end of the second section of the stent. The memory alloy wire returns to its original shape when the fluid pressure decreases, and applies a force to the second section of the stent to cause the radial dimensions of the second section of the stent to change together.

[0015] Preferably, the push rod is provided with a connecting hole at the distal end of the fluid delivery channel, and one end of the hollow tube is connected to the connecting hole to facilitate the liquid in the fluid delivery channel to flow to the inner cavity of the hollow tube at the distal end of the second section of the bracket.

[0016] Preferably, the push rod comprises a grinding section, and the grinding section is connected to the cavity section by laser butt welding.

[0017] Preferably, the second section of the bracket and the push rod can be connected by hot melting, glue dispensing or other sealing methods.

[0018] Preferably, the second section of the bracket includes a rod body, and at least four developing points are arranged on the rod body.

[0019] Preferably, the fluid delivery channel and the inner cavity of the hollow tube are filled with fluid in an initial state.

[0020] Preferably, the fluid transported by the fluid transport channel is physiological saline.

[0021] Beneficial effects:

[0022] (1) The present invention provides a hollow tube connected to the stent body. The hollow tube allows fluid to pass through. The inner cavity is connected to the fluid delivery channel. The pressure of the hollow tube is changed by controlling the amount of fluid in the fluid delivery channel, so that the hollow tube changes its size under pressure. The hollow tube is tightly connected to the stent body. When the size of the hollow tube changes, the connection point between the hollow tube and the stent body changes accordingly, thereby improving the adaptability of the stent body to the inner wall of the blood vessel and better fitting the variable diameter blood vessel.

[0023] (2) The present invention arranges a memory alloy wire in the inner cavity of the hollow tube. The outer contour of the memory alloy wire in the initial state is matched with the outer contour of the distal end of the second section of the stent. When the hollow tube expands as the fluid pressure increases, the memory alloy wire expands along with the hollow tube. After the fluid pressure in the hollow tube decreases, the memory alloy wire has a tendency to return to its original state and applies force to the second section of the stent so that the size of the outer diameter of the second section of the stent is restored. The memory alloy wire drives the hollow tube to automatically restore, thereby improving the restoration efficiency, reducing the manual restoration process, and helping to improve efficiency.

[0024] (3) The present invention provides multiple groups of stent two sections, each group being connected to a different fluid delivery channel, so that the two sections of the stent can be controlled separately, which provides better adaptability when facing blood vessels with high tortuosity and multiple changes in inner diameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0026] Figure 1 This is a schematic diagram of the structure of a thrombus in an existing variable diameter blood vessel.

[0027] Figure 2 FIG. 1 is a schematic diagram of the structure of a thrombectomy stent in a variable diameter vessel according to an embodiment of the present invention.

[0028] Figure 3 Schematic diagram of the overall structure of the thrombus removal stent in Examples 1, 4 and 5 of the present application.

[0029] Figure 4 It is a schematic diagram of the cross-sectional structure of the push rod in Examples 1, 4 and 5 of the present application.

[0030] Figure 5 Schematic diagram of the overall structure of the thrombus removal stent in Example 2 of the present application.

[0031] Figure 6 This is a schematic diagram of the cross-sectional structure of the push rod in Example 2 of the present application.

[0032] Figure 7Schematic diagram of the side view structure of the multi-section thrombus removal stent in Examples 1, 4 and 5 of the present application.

[0033] Figure 8 Schematic diagram of the main structure of the multi-section thrombus removal stent in Examples 1 and 5 of the present application.

[0034] Fig. 9 This is a schematic diagram of the cross-sectional structure of the hollow tube in Example 3 of the present application.

[0035] In the figure: 1. bracket body; 11. bracket section one; 12. bracket section two; 121. developing point; 122. rod body; 2. push rod; 21. cavity section; 211. fluid conveying channel; 212. connecting hole; 213. partition plate; 214. rubber plug; 22. grinding section; 23. extension section; 3. hollow tube; 31. memory alloy wire. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0038] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be internal connection between two elements, indirect connection, or an interactive relationship between two elements.

[0041] In the description of the present invention, "before use" refers to the state where the multi-section thrombectomy stent with variable outer diameter has not been used, has not entered the human body, or has not come into contact with body fluids such as blood, tissue fluid, etc. in the human body, and "when in use" refers to the state where the multi-section thrombectomy stent with variable outer diameter has entered the human body or has come into contact with body fluids such as blood, tissue fluid, etc. in the human body.

[0042] In the description of the present invention, "initial state" refers to the state of the fluid in the hollow tube and the fluid delivery channel without human intervention, and the hollow tube is at a default fluid pressure.

[0043] In the description of the present invention, when considering the orientation of the technical features of the present application, the end first placed in the blood vessel during surgery is the distal end, and the end close to the operator is the proximal end.

[0044] The present invention will be described in detail below in conjunction with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0045] The outer diameters of the current thrombectomy stents on the market are generally the same. For serious and tortuous blood vessels, choosing a thrombectomy stent with a larger outer diameter will cause wear and scratches on the blood vessel wall, while a thrombectomy stent with a smaller outer diameter has insufficient radial support and poor wall adhesion, which is prone to instability such as displacement, affecting the effectiveness of the thrombectomy stent, resulting in the thrombectomy stent's ability to capture thrombi being weakened, and thrombi are easily detached from the thrombectomy stent during the recovery process. Therefore, it is necessary to solve the problem of insufficient adaptability of the thrombectomy stent to tortuous blood vessels.

[0046] According to one embodiment of the present invention, Figure 1 and Figure 2As shown, for severe and tortuous blood vessels or blood vessels with variable diameter sections, choosing a thrombectomy stent that matches the inner diameter of the variable diameter blood vessel will cause wear and scratches on the inner wall of the blood vessel at the smaller inner diameter. Choosing a thrombectomy stent that matches the smaller inner diameter of the variable diameter blood vessel will have lower support force and poorer wall adhesion at the larger inner diameter of the blood vessel, which is prone to unstable phenomena such as displacement, affecting the effectiveness of the product and weakening its ability to capture thrombi. The thrombi are very likely to fall off the stent during the recovery process. The present invention provides a thrombectomy stent with a variable outer diameter. The thrombectomy stent adopts a multi-segment design. Changing the outer diameter of one or more segments of the stent can change the outer diameter of the entire thrombectomy stent, thereby better fitting the shape of the blood vessel, such as Figure 2 shown.

[0047] According to one embodiment of the present invention, Figures 3 to 6As shown, a multi-section thrombectomy stent with a variable outer diameter includes a stent body 1 and a push rod 2 connected to the stent body 1. In one embodiment, the distal end of the push rod 2 is fixedly connected to the proximal end of the stent body 1. The push rod 2 is used to push out the stent body 1 pressed in the sheath tube, so that the stent body 1 is released at the thrombus, thereby capturing the embolus. In one embodiment, a hollow tube 3 is provided on the stent body 1. The hollow tube 3 is a flexible hose with a hollow interior. There is no limitation on its cross-sectional shape, and there is no specific limitation on the cross-sectional shape of the through hole, as long as the hollow tube 3 allows fluid to pass through. The proximal end of the hollow tube 3 is connected to the push rod 2. In one embodiment, a part of the push rod 2 is a cavity section 21. In this embodiment, the push rod 2 includes a solid distal end and a cavity section 21. The cavity section 21 includes a fluid delivery channel 211. In one embodiment, the cavity section 21 includes one fluid delivery channel 211. In another embodiment, the cavity section 21 includes two fluid delivery channels 211. In other embodiments, the cavity section 21 includes three, four or six fluid delivery channels 211. When there are multiple fluid delivery channels 211, each fluid delivery channel 211 is separated by an isolation component. According to one embodiment of the present invention, the fluid delivery channel 211 is connected to the inner cavity of the hollow tube 3. In this embodiment, the number of the hollow tubes 3 corresponds to the number of the fluid delivery channels 211, and each hollow tube 3 is independently connected to the fluid delivery channel 211, so that fluid can be independently delivered to each fluid delivery channel 211, so that the part where the stent body 1 is connected to the hollow tube 3 gradually expands under the pressure of the fluid, so as to achieve the purpose of changing the outer diameter size of different sections of the thrombus removal stent. According to one embodiment of the present invention, in the radial direction, the size of the connection part between the stent body 1 and the hollow tube 3 in the state of not conveying fluid is smaller than the size of the connection part between the stent body 1 and the hollow tube 3 in the state of conveying fluid. In another embodiment, in addition to the change in radial size, due to the expansion of the hollow tube 3 at the stent, the stent of this section is driven to expand in the radial direction, resulting in the change in the axial size of this section of the stent, specifically, the stent of this section moves toward the proximal end, causing its axial size to shrink. The fluid in this embodiment is physiological saline, contrast agent, gas or other liquid that is harmless to human blood vessels.

[0048] The distal end of the hollow tube 3 is connected to the distal end of the second section 12 of the stent in a winding manner. Specifically, the distal end of the second section 12 of the stent is circumferentially intertwined with the distal end of the hollow tube 3, and the distal end of the hollow tube 3 is self-closed to form a ring. In the initial state, fluid is provided in the fluid delivery channel 211, the connecting hole 212 and the hollow tube 3. The fluid is preferably physiological saline. Even if the hollow tube 3 is broken, the fluid flows into the blood and has little effect on the patient's health. The filling or leakage of the fluid in the hollow tube 3 is controlled by controlling the flow of the fluid in the fluid delivery channel 211 at the proximal end. After the fluid in the hollow tube 3 is filled, the fluid pressure becomes larger, and the hollow tube 3 gradually expands under the pressure of the fluid, driving the second section 12 of the stent to further expand to fit with the inner wall of the blood vessel, increasing the radial size of the second section 12 of the stent, thereby improving the wall adhesion effect on the blood vessel. The size of the fluid pressure in the hollow tube 3 is controlled by controlling the flow of the fluid, and then the expansion and contraction of the hollow tube 3 is controlled, driving the second section 12 of the stent to expand and contract.

[0049] Preferably, the grinding section 22 and the cavity section 21 of the push rod 2 are located outside the patient's body, and a rubber plug 214 is inserted into the proximal end of the cavity section 21. The rubber plug 214 seals the proximal end of the fluid delivery channel 211. The syringe needle is inserted into the rubber plug 214, and the piston rod is pushed and pulled to control the fluid pressure in the hollow tube 3. Since the cavity section 21 has poor elasticity, the fluid pressure will be concentrated and released at the hollow tube 3, so that the expansion efficiency of the hollow tube 3 is improved.

[0050] The radial ends of the grinding section 22 are ground, and the diameter gradually decreases from the cavity section 21 to the extension section 23. The diameter of the cavity section 21 is larger than that of the extension section 23. The operator can easily control the pressure in the hollow tube 3 through the fluid delivery channel 211, which facilitates the surgical operation.

[0051] Preferably, both the first and second stent sections 11 and 12 are inlaid with developing points 121, and the developing points 121 are distributed at equal intervals in the circumferential direction. During the expansion process of the first and second stent sections 11 and 12, the expansion status of the first and second stent sections 11 and 12 is judged by observing the positions of the developing points 121 through the developing equipment, and then the combination status of the first and second stent sections 11 and 12 with the thrombus is judged, so that the whole operation can be visualized and the surgeon can make judgments conveniently.

[0052] The inner cavity of the hollow tube 3 is provided with a memory alloy wire 31, and the outer contour of the memory alloy wire 31 is adapted to the outer contour of the distal end of the second section 12 of the stent. When the hollow tube 3 expands with the increase of fluid pressure, the memory alloy wire 31 expands with the hollow tube 3. After the fluid pressure in the hollow tube 3 decreases, the memory alloy wire 31 returns to its original state and applies force to the second section 12 of the stent to restore the size of the outer diameter of the second section 12 of the stent. By providing the memory alloy wire 31, the recovery efficiency is improved, and manual recovery is not required, saving operation steps.

[0053] The following is a detailed description of a multi-section thrombectomy stent with a variable outer diameter according to the present invention through specific embodiments.

[0054] Example 1

[0055] This embodiment provides a multi-section thrombus removal stent with a variable outer diameter, such as Figure 3 , 4 , 7 and 8, a multi-segment thrombectomy stent with a variable outer diameter includes a stent body 1, which is formed by laser cutting of nickel-titanium hypotubes, and the stent body 1 is in the shape of a spiral cross of multiple strands of nickel-titanium hypotubes. Preferably, the stent body 1 includes a plurality of mutually connected stent sections 11. In the present embodiment, there are two stent sections 11, and the proximal end of the stent section 11 is connected to a stent section 2 12, and the distal end of the stent section 2 12 is connected to the hollow tube 3. Specifically, the distal end of the hollow tube 3 is connected to the circumference of the distal end of the stent section 12 in a threading manner, and is closed to form a ring. The threading manner here means that the hollow tube 3 and the stent section 12 are intertwined in a clamp-like manner. Obviously, the distal end of the hollow tube 3 and the distal end of the stent section 12 are intertwined in the circumferential direction, and the hollow tube 3 is tightly combined with the stent section 12. The hollow tube 3 is a retractable tube body with an inner cavity in the middle, and the inner cavity is used to accommodate a fluid.

[0056] The proximal end of the second section 12 of the bracket is connected with the push rod 2. Specifically, the proximal end of the second section 12 of the bracket is connected to the push rod 2 by hot melting. In other embodiments of the present application, the proximal end of the second section 12 of the bracket is connected to the push rod 2 by dispensing or bonding.

[0057] The proximal end of the hollow tube 3 is connected to the push rod 2, and the push rod 2 includes a cavity section 21 and a grinding section 22. The cavity section 21 includes a fluid delivery channel 211. The cavity section 21 is provided with a connecting hole 212 connected to the fluid delivery channel 211, and the connecting hole 212 is preferably located at the distal end of the fluid delivery channel 211. The proximal end of the hollow tube 3 is bonded to the connecting hole 212 of the cavity section 21 to achieve a sealed connection to prevent fluid leakage. The hollow tube 3 can also be connected to the connecting hole 212 by hot melting. The purpose of the above technical solution is to allow the liquid in the fluid delivery channel 211 to flow conveniently into the hollow tube 3.

[0058] In the state where no fluid is delivered, the inner cavity of the hollow tube 3 and the fluid delivery channel 211 are filled with fluid, and the fluid is preferably physiological saline. In the state where fluid is delivered, fluid is injected into the fluid delivery channel 211 to increase the fluid pressure inside the hollow tube 3. The hollow tube 3 gradually expands under the pressure of the fluid, driving the second section 12 of the stent to expand until it fits the inner wall of the blood vessel, thereby improving the adhesion effect on the blood vessel. The outer diameter of the second section 12 of the stent is adjusted by controlling the pressure of the fluid filling, so as to achieve better adhesion to the inner wall of the variable diameter blood vessel.

[0059] In the above technical solution, at least in the radial direction, the size of the connection part between the stent body 1 and the hollow tube 3 in the state where the fluid is not transported is smaller than the size of the connection part between the stent body 1 and the hollow tube 3 in the state where the fluid is transported.

[0060] Since the hollow tube 3 needs to expand to drive the second section 12 of the stent to expand, the outer ring of the hollow tube 3 must be made of a material with good toughness during the expansion and contraction process, such as polyurethane (PU) to prevent the outer ring of the hollow tube 3 from breaking during the expansion and contraction process and the fluid in the inner cavity of the hollow tube 3 from flowing into the patient's blood vessels.

[0061] The fluid may be a liquid or gas that is harmless to human blood vessels. The fluid is preferably physiological saline. When the hollow tube 3 ruptures unexpectedly, the fluid entering the blood vessels has little impact on the patient's health. In other embodiments, the fluid may also be a contrast agent or a gas.

[0062] When in use, after the fluid pressure in the inner cavity of the hollow tube 3 increases, the hollow tube 3 drives the second section 12 of the stent to expand, while the first section 11 of the stent is still in its original expanded state, which can better adapt to the tortuous blood vessel segment, so that the first section 11 of the stent and the second section 12 of the stent respectively fit the inner walls of blood vessels with different inner diameters, thereby improving the adhesion effect to the blood vessels.

[0063] Example 2

[0064] This embodiment discloses a multi-section thrombus removal stent with a variable outer diameter. Figure 5 and Figure 6 As shown, the difference from the first embodiment is that: there are two bracket sections 11, and there are also two bracket sections 12. The distal end of each bracket section 12 is connected to a hollow tube 3. A partition plate 213 is welded or integrally formed in the middle of the cavity section 21. The partition plate 213 is arranged along the length direction of the cavity section 21 to divide the fluid delivery channel 211 into two parts along the radial direction. The cavity section 21 is provided with two connecting holes 212 respectively connected to each fluid delivery channel 211, and the hollow tube 3 is connected to the connecting holes 212 of the cavity section 21 in a one-to-one correspondence.

[0065] For blood vessels with multiple diameter changes, different amounts of fluid can be injected into the fluid delivery channel 211 to control the expansion degree of different stent segments 12, so that the stent segments 12 can fit the inner walls of blood vessels with different inner diameters respectively, thereby improving the adhesion effect on the blood vessels.

[0066] It can be understood by those skilled in the art that multiple groups of stent second sections 12 are connected to the hollow tube 3, and multiple partition plates 213 in a circular array are set with the center as the base point in the cavity section 21 to divide the fluid delivery channel 211 into multiple groups of channels corresponding to the number of stent second sections 12. The expansion degree of different stent second sections 12 is controlled by the amount of injected fluid to improve the adhesion effect on the blood vessel wall.

[0067] Example 3

[0068] This embodiment further describes the hollow tube 3 based on the first embodiment.

[0069] like Fig. 9 As shown, a memory alloy wire 31 is provided at the inner cavity of the hollow tube 3, and the memory alloy wire 31 is a nickel-titanium shape memory alloy wire 31. In the initial state, the outer contour of the memory alloy wire 31 matches the outer contour of the distal end of the second section 12 of the stent. When the hollow tube 3 is filled with fluid and expands, the memory alloy wire 31 expands with the expansion of the hollow tube 3. After the fluid in the hollow tube 3 is partially discharged, the fluid pressure decreases, and the memory alloy wire 31 returns to its original state under the condition of reduced fluid pressure, and applies a force to the second section 12 of the stent to cause the radial size of the second section 12 of the stent to change. The purpose of setting the memory alloy wire 31 is to facilitate the automatic recovery of the outer diameter of the second section 12 of the stent, and to realize the free switching of the outer diameter of the second section 12 of the stent.

[0070] The push rod 2 also includes an extension section 23. The distal end of the grinding section 22 is connected to the cavity section 21 by laser butt welding to prevent leakage of fluid in the fluid delivery channel 211. The proximal end of the grinding section 22 is integrally formed with the extension section 23. Both sides of the grinding section 22 are ground, and the diameter gradually decreases from the cavity section 21 to the extension section 23. The diameter of the cavity section 21 is larger than the extension section 23 extending into the patient's blood vessel, which is convenient for the operator to operate.

[0071] Example 4

[0072] This embodiment further describes the bracket body 1 based on the first embodiment.

[0073] Reference Figure 3 and Figure 7 As shown, the second section 12 of the bracket includes a rod body 122 , and at least four developing points 121 are inlaid on the rod body 122 .

[0074] Preferably, there are four developing points 121, which are distributed in a circular shape and at equal intervals on the rod body 122. After the second section 12 of the stent expands, the developing points 121 move accordingly. The operator can judge the combination state of the second section 12 of the stent and the thrombus by observing the position state of the four developing points 121, which is helpful for the operator to make accurate judgments and decisions.

[0075] In a preferred embodiment of the present application, developing points 121 are provided on both the first and second sections of the stent 11 and 12, and developing points 121 are embedded on each section. During the operation, whether the first and second sections of the stent 11 and 12 are combined with the thrombus can be judged according to the opening conditions of each developing point 121, so that the entire operation can be visualized.

[0076] Example 5

[0077] like Figure 3 , 4 As shown in , 7 and 8, the difference between this embodiment and the first embodiment is that: when the outer diameter of the first section of the stent 11 is larger than the outer diameter of the blood vessel after the first section of the stent 11 is automatically expanded, in order to prevent the first section of the stent 11 from causing wear and scratches on the blood vessel wall, the distal end of the hollow tube 3 is connected to the distal end of the first section of the stent 11, and the connection method is the same as that in the first embodiment. By extracting part of the fluid in the fluid delivery channel 211 to reduce the pressure in the inner cavity of the hollow tube 3, the inner cavity of the hollow tube 3 drives the first section of the stent 11 to contract, thereby reducing the wear of the first section of the stent 11 on the blood vessel wall and reducing surgical injuries.

[0078] In summary: by setting a hollow tube 3 connected to the distal end of the second section 12 of the stent, the proximal end of the hollow tube 3 is connected to the circulation delivery channel. When the distal end of the second section 12 of the stent is in the initial state, the stent body 1 can easily pass through a blood vessel with a thinner diameter. When the distal end of the stent body 1 reaches the specified position, the fluid is delivered to the inner cavity of the hollow tube 3 through the fluid delivery channel 211 so that the distal end of the second section 12 of the stent is in an expanded state, so that the second section 12 of the stent can better fit the inner wall of the blood vessel, increase the ability to grasp the thrombus in the variable diameter blood vessel and the tortuous blood vessel segment, reduce the probability of thrombus detachment during the recovery process, and improve the adaptability of the second section 12 of the stent to the inner wall of the blood vessel. The above technical solution does not need to repeatedly grasp the thrombus, reduces the time of the interventional surgery and the difficulty of the operator's operation, and improves the efficiency of the interventional surgery. At the same time, it can reduce the risk of various complications during the operation, improve the success rate of the operation, and reduce the pain of the patient. In addition, the risk of blocking the distal end of the blood vessel is also reduced.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-section thrombus removal stent with variable outer diameter, characterized in that: It comprises a support body (1) and a push rod (2) connected to the support body (1); A hollow tube (3) is provided on the support body (1) and is connected to the push rod (2); Part of the push rod (2) is a hollow section (21), and the hollow section (21) includes a fluid delivery channel (211), and the fluid delivery channel (211) is connected to the inner cavity of the hollow tube (3) and is used to deliver fluid to the inner cavity of the hollow tube (3) so that the portion where the stent body (1) and the hollow tube (3) are connected gradually expands under the pressure of the fluid; In the radial direction, the size of the connection portion between the support body (1) and the hollow tube (3) in a state where fluid is not being transported is smaller than the size of the connection portion between the support body (1) and the hollow tube (3) in a state where fluid is being transported.

2. The multi-section thrombus removal stent with variable outer diameter according to claim 1, characterized in that: The stent body (1) comprises a plurality of mutually connected stent sections (11), a stent section (12) whose distal end is connected to the stent section (11), the distal end of the stent section (12) is connected to the hollow tube (3), and the proximal end of the stent section (12) is connected to the push rod (2).

3. The multi-section thrombus removal stent with variable outer diameter according to claim 2, characterized in that: The distal end of the hollow tube (3) is connected to the circumference of the distal end of the second section (12) of the stent in a threading manner and is closed to form a ring.

4. The multi-section thrombus removal stent with variable outer diameter according to claim 3, characterized in that: A memory alloy wire (31) is arranged inside the hollow tube (3), and the outer contour of the memory alloy wire (31) is adapted to the outer contour of the distal end of the second section (12) of the stent. When the fluid pressure is reduced, the memory alloy wire (31) returns to its original state and applies a force to the second section (12) of the stent to cause the radial dimension of the second section (12) of the stent to change.

5. The multi-section thrombus removal stent with variable outer diameter according to claim 4, characterized in that: The push rod (2) is provided with a connecting hole (212) located at the far end of the fluid delivery channel (211), and one end of the hollow tube (3) is connected to the connecting hole (212), so that the liquid in the fluid delivery channel (211) flows to the inner cavity of the hollow tube (3) located at the far end of the second section (12) of the bracket.

6. The multi-section thrombus removal stent with variable outer diameter according to claim 1, characterized in that: The push rod (2) comprises a grinding section (22), and the grinding section (22) is connected to the cavity section (21) by laser butt welding.

7. A multi-section thrombectomy stent with variable outer diameter according to any one of claims 1 to 6, characterized in that: The second section of the bracket (12) and the push rod (2) can be connected by hot melting, glue dispensing or other sealing methods.

8. The multi-section thrombus removal stent with variable outer diameter according to claim 7, characterized in that: The second bracket section (12) comprises a rod body (122) and at least four developing points (121) arranged on the rod body (122).

9. The multi-section thrombus removal stent with variable outer diameter according to claim 1, characterized in that: The fluid delivery channel (211) and the inner cavity of the hollow tube (3) are filled with fluid in the initial state.

10. The multi-section thrombus removal stent with variable outer diameter according to claim 9, characterized in that: The fluid transported by the fluid transport channel (211) is physiological saline, contrast agent or gas.

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