Filterable iliac vein stent set

Abstract

This invention discloses an iliac vein stent assembly capable of filtering thrombi, relating to the field of vascular stent technology, and particularly to an iliac vein stent assembly capable of filtering thrombi. It comprises an iliac vein stent and a vena cava filter. The iliac vein stent is bifurcated; the long and short branches of the stent are released into the left and right iliac veins respectively, and are fixed to the main stent with barbs. The main stent is released at the common iliac vein at the confluence of the left and right iliac veins. The fixing ring serves as the anchor point for the vena cava filter, connecting the vena cava filter and the iliac vein stent together to form a stent assembly. The vena cava filter's claws and support frame are made of the same shape-memory metal tube, and the connecting rod is a nickel-titanium tube body. The claws rotate within the fixing ring, and the connecting rod moves back and forth within the fixing ring. This invention comprehensively solves iliac vein compression syndrome, effectively prevents stent displacement during postoperative recovery, and prevents postoperative thrombus flow to the pulmonary artery, making it suitable for patients with contraindications to thrombolysis.

Description

Technical Field

[0001] This invention relates to the field of vascular stent technology, and in particular to an iliac vein stent assembly capable of filtering thrombi. Background Technology

[0002] Venous diseases are currently among the most common vascular surgical conditions, especially iliac vein compression syndrome. Iliac vein compression syndrome refers to a syndrome caused by compression of the iliac vein, leading to adhesions, stenosis, or occlusion within the vascular lumen, and consequently, various clinical symptoms. The incidence of iliac vein compression syndrome is approximately 20%–40% of lower extremity venous diseases. Anatomically, in iliac vein compression syndrome, the right iliac artery crosses the left iliac vein, and the inferior iliac vein is compressed by the iliac artery, resulting in narrowing of the venous lumen. When blood passes through the narrowed iliac vein, hemodynamic changes occur, greatly increasing the risk of lower extremity venous thrombosis. Therefore, clinically, minimally invasive endovascular interventional treatment is commonly used, involving the placement of a vascular stent in the diseased segment of the vessel to support the narrowed or occluded segment, reduce elastic recoil and remodeling, and maintain unobstructed blood flow. Endovascular interventional placement of an iliac vein stent in the diseased segment of the left common iliac vein is the preferred method for treating iliac vein compression syndrome. Based on the anatomical features of the veins, there are several different situations of iliac vein compression: compression of the right common iliac vein by the right common iliac artery, compression of the left common iliac vein, compression of the junction of the inferior vena cava and the right common iliac vein, etc., can all cause iliac vein stenosis.

[0003] Currently, most stents used to treat iliac vein compression syndrome are straight-tube stents with an oblique design near the vena cava. While these straight stents are effective for compressing a single layer of the iliac vein, they have significant limitations. They are not very effective when the right iliac vein and the proximal vena cava are compressed. Some innovative designs exist, such as bifurcated stents supporting both iliac veins, which can resolve most compression issues. However, through discussions with several clinicians, it has been found that both straight and bifurcated stents share a common post-implantation complication: thrombosis. New thrombi easily form immediately after stent implantation due to the large diameter of the iliac vein, high radial force, and high metal coverage. Bifurcated stents, in particular, have a much higher metal coverage than straight stents, making new thrombi formation highly likely after surgery. Furthermore, some patients with contraindications to thrombolysis, intracranial tumors, or recent surgery cannot undergo thrombolytic therapy, as this could easily lead to intracranial hemorrhage or massive hemorrhage. Some patients have pre-existing deep vein thrombosis in their lower extremities. After surgery, previously old deep veins may dislodge, but because the stent has just been implanted and the stent and vessel wall are not yet fully endothelialized, direct instrumental thrombectomy is not possible, as it could easily cause stent migration. If the thrombus dislodges (embolizes) and travels to the lungs, it can become a life-threatening pulmonary embolism (PE). On the other hand, because the blood flow at the junction of the iliac vein and the vena cava is relatively strong, and this area also has a large range of motion, straight stents are prone to migration after implantation. Therefore, many patients experience iliac vein compression again shortly after surgery. Bifurcation stents can bind the left and right iliac veins, effectively preventing stent migration distally. However, venous blood flows proximally, which can easily carry the stent proximally. Therefore, there is an urgent need in this technical field for a stent kit suitable for patients with contraindications to thrombolysis that can comprehensively resolve iliac vein compression syndrome, prevent stent migration during the postoperative recovery period, and prevent postoperative thrombus travel to the pulmonary artery. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is a stent kit suitable for patients with contraindications to thrombolysis that can comprehensively solve iliac vein compression syndrome, prevent stent displacement during the postoperative recovery period, and prevent postoperative thrombus flow to the pulmonary artery.

[0005] To achieve the above objectives, the present invention provides an iliac vein stent assembly capable of filtering thrombi.

[0006] An iliac vein stent assembly, characterized in that it comprises an iliac vein stent (100) and a vena cava filter (200), wherein: the iliac vein stent includes a long branch (101), a short branch (102), barbs (103), a fixing ring (104), and a main stent (105); the stent is bifurcated; the long branch (101) and the short branch (102) are released into the left and right iliac veins respectively, the barbs are fixed to the main stent, and the main stent is released at the common iliac vein at the confluence of the left and right iliac veins; the barbs form an angle of 10-80 degrees with the main stent, and the direction of the barbs is opposite to that of the long branch and the short branch; the fixing ring serves as the anchor point for the vena cava filter, so that... The vena cava filter and the iliac vein stent are connected together to form a stent assembly; the vena cava filter includes a support frame (201), a top filter screen (202), a claw (204), a contrast ring (205), a large support ring (206), and a connecting rod (208); the main support frame (201) and the large support ring (206) of the vena cava filter are cut from a single piece of memory metal tube, and expanded and heat-treated to form a tapered structure that is larger at the top and smaller at the bottom through an expansion mold; the claw and the support frame are made of the same memory metal tube, the connecting rod is the main body of the memory metal tube, the claw is laser-cut into multiple segments and shaped into a semi-circular hook-shaped claw, the claw rotates in the fixed ring; the connecting rod moves back and forth in the fixed ring.

[0007] In a preferred embodiment of the present invention, the iliac vein stent is made entirely of shape memory metal, and the structure is woven or laser-engraved.

[0008] In a preferred embodiment of the present invention, the braiding density of the long branch of the support is increased or double-layer braiding is used; the braiding lengths of the long and short branches of the support are adjustable.

[0009] In a preferred embodiment of the present invention, the weaving density of the main support segment is adjustable; after the support is woven, it is shaped using a mold and then subjected to heat treatment and annealing.

[0010] In a preferred embodiment of the present invention, the iliac vein stent is laser-engraved from nickel-titanium tubing.

[0011] In a preferred embodiment of the invention, the barbs are made of a biodegradable material; the biodegradable material is made into a thin film with barbs or barbed threads, which are then coated on the main support section, or the threads are wound around a mesh.

[0012] In a preferred embodiment of the present invention, the top filter screen of the vena cava filter is woven from nickel-titanium wire wound around a 206-large support ring as a fixing point.

[0013] In a preferred embodiment of the present invention, the top filter screen of the vena cava filter is a filter groove cut from a nickel-titanium sheet, and the filter groove is cut into different shapes.

[0014] In a preferred embodiment of the present invention, the support frame (201) of the vena cava filter also has a peripheral filter (203), the peripheral filter has the same structure as the top filter and is fixed on the small support ring (207).

[0015] In a preferred embodiment of the present invention, the imaging ring of the vena cava filter is made of platinum or tannin and is welded to the proximal end of the connecting rod near the claw position.

[0016] Technical effect

[0017] This invention flexibly combines a vena cava filter and an iliac vein stent. The vena cava stent can be fixed to the iliac vein stent and is easy to retrieve and replace. This ensures that after iliac vein stent surgery, newly formed thrombi and dislodged old thrombi can all be captured by the vena cava filter, preventing thrombi from traveling to the pulmonary artery and causing acute pulmonary embolism, which can be life-threatening. Simultaneously, the anchoring claws of the vena cava filter are made of shape-memory metal, possessing excellent strength and deformation recovery capabilities. After the iliac vein stent is deployed, the vena cava filter is released through the catheter using the fixing ring on the iliac vein stent. The claws of the vena cava filter self-expand and hook onto the iliac vein fixing ring, ensuring that the vena cava filter will not dislodge from the fixing ring. If the vena cava filter needs to be replaced later, the self-expanding claws of the filter can be hooked by the interventional catheter retrieval mechanism, compressing and retrieving the filter along with itself into the catheter. This facilitates easy removal and replacement of the filter later, saving surgical costs, reducing surgical difficulty and risks, and minimizing patient suffering.

[0018] Meanwhile, this invention designs the vena cava stent with a "diamond" structure, reducing the contact area with the blood vessel wall and effectively decreasing endothelialization of the blood vessel wall and filter. The filter's unique claw anchoring mechanism ensures a secure connection between the filter and the stent while also allowing the blood flow to drive the vena cava filter to swing and rotate, ensuring that the filter is not completely fixed. This prevents the vena cava filter from adhering to the blood vessel wall and significantly increases the time the filter can remain in the body.

[0019] Furthermore, the iliac vein stent is designed with a forked structure, corresponding to the left and right iliac veins respectively. The lengths of the different branches of the stent can be adjusted, and the stent mesh density is variable. The stent can be woven or laser-cut, and the cut stent can be designed with reinforcing ribs to improve its radial support. This stent structure can address various iliac vein compression conditions, and the radial support can be adjusted according to the stent mesh density. The stent length can also be freely controlled, thus fundamentally resolving venous thrombosis caused by iliac vein compression.

[0020] By placing the iliac vein stent in the main stent segment of the inferior vena cava, 2-4 rows of barbs are used to increase the friction between the iliac vein stent and the vessel wall, strengthening stent anchorage. For a period of time after surgery, it will not be carried away by blood flow and will not be affected by movement, thus providing stable support for the narrowed area of ​​the vessel and resolving the problem of iliac vein compression.

[0021] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an iliac vein stent assembly according to a preferred embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of an iliac vein stent according to a preferred embodiment of the present invention;

[0024] Figure 3 This is a laser engraving schematic diagram of an iliac vein stent according to a preferred embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of a vena cava filter according to a preferred embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of an iliac vein stent assembly according to another preferred embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of a vena cava filter according to another preferred embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the top filter screen of another preferred embodiment of the present invention;

[0029] Figure 8 This is an enlarged schematic diagram of the engagement of the claw and the retaining ring in a preferred embodiment of the present invention;

[0030] Figure 9 This is a schematic diagram showing the delivery of the stent tip through the blood vessel into the iliac vein, passing through the fixation ring;

[0031] Figure 10 This is a schematic diagram showing the vena cava filter being released after the catheter is withdrawn;

[0032] Figure 11 This is a schematic diagram showing the complete deployment of the vena cava filter;

[0033] Figure 12 This is a schematic diagram of the vena cava filter recovery process. Detailed Implementation

[0034] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0035] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0036] The iliac vein stent assembly mainly consists of a 200-vena cava filter and a 100-iliac vein stent, see appendix. Figure 1 A combination of vena cava filters and iliac vein stents is used.

[0037] like Figure 1 The 100-iliac vein stent is mainly composed of 101-stent long branch, 102-stent short branch, 103-barb, 104-fixation ring, and 105-main stent. The stent is bifurcated, with the two long branches deployed into the left and right iliac veins respectively, and the 105-main stent deployed at the common iliac vein where the left and right iliac veins meet. The 100-iliac vein stent is entirely constructed of shape-memory metal, which can be nickel-titanium, and the structure can be braided or laser-cut. The braided structure is relatively simple to manufacture and provides strong radial support at the same metal coverage. The braided wire diameter is 0.05-1.9mm, and the braiding method can be adjusted according to the treatment segment. For example, in most clinical cases, the left iliac vein segment is compressed while the right iliac vein is less compressed. We need to increase the braiding density of the 101-stent long branch, and if necessary, use double-layer braiding. This greatly enhances the radial support of the stent after complete deployment in the left iliac vein, completely expanding the stenotic area and facilitating blood flow recanalization. When the left iliac vein compression segment is relatively long, the braiding length of the 101-stent long branch can be increased, resulting in a longer treatment segment within the iliac vein. Simultaneously, considering the relatively low compression force and short compression segment of the right iliac vein, the braiding length of the 102-stent short branch can be reduced, while increasing the braiding mesh spacing, decreasing the mesh density, reducing metal coverage, and minimizing new thrombus formation in the early stages of implantation. Currently, some clinical cases involve iliac artery compression of the common iliac vein segment; therefore, the 105-main stent segment also utilizes oblique braiding with reduced mesh size and increased braiding density to enhance radial support in certain areas of the 105-main stent.

[0038] After the stent is woven, it is shaped using a mold and then heat-treated for annealing. The heat treatment temperature is 300℃-650℃, and the time is 2-45 minutes. The heat-shaped stent can maintain a specific shape and has excellent memory properties. The 100-iliac vein stent can be freely compressed into the delivery catheter and self-expands during deployment, eliminating the need for additional balloon dilation, simplifying the procedure and saving patients money.

[0039] The 103-barb is fixed to the 105-main stent, constructed of nickel-titanium or other metal materials, and secured to the 105-main stent using welding technology. The barb forms a 10-80 degree angle with the 105-main stent, and its tip points are opposite in direction to the long branch of the 101-stent and the short branch of the 102-stent. The tip length is 0.2-2 mm to ensure it will not perforate the vessel wall. Within the 105-main stent segment, the barbs are distributed in 2-5 rows, with 3-9 barbs per row around the stent.

[0040] In another embodiment, the 103-barbs are made of a biodegradable material. Biodegradable materials include, but are not limited to, polyglycolic acid (PGA), polylactic acid (PLA), and polylactic-glycolic acid copolymer (PLGA). The biodegradable material is fabricated as a barbed film or barbed threads, which are then used to coat the 105-main stent segment, or the threads are wound around a mesh. This absorbable barb design ensures reinforced anchorage of the 100-iliac vein stent while reducing damage to the vessel wall from the barbs.

[0041] 104-The retaining ring is a metal ring-shaped part fixed to 105-the main support. Its inner diameter is slightly larger than that of 402-the conveying pipe. See [link / reference]. Figure 9 This facilitates the passage and release of the delivery tube through and from the 200-vena cava filter, such as... Figure 3 As shown. The fixation ring primarily serves as an anchor point for the 200-vena cava filter, connecting it to the 100-iliac vein stent to form a stent assembly. The 104-fixation ring is made of metal, including but not limited to nickel-titanium and stainless steel, and is fixed to the 105-main stent by welding. Alternatively, it can be directly fixed using a braided structure formed by the braided wires of the 105-main stent segment. Direct braided fixation eliminates the welding process, reducing production costs.

[0042] In another embodiment of the invention, the 100-iliac vein stent is laser-engraved from nickel-titanium tubing. It undergoes heat treatment for shaping, grinding and polishing, acid pickling to remove the oxide layer, and electrochemical polishing. The laser-engraved pattern can be of various shapes. Figure 2This is a schematic diagram of one type of laser-engraved pattern. The 301-support unit has a Z-shaped structure, and the stent has 3-8 302-bridge ribs per week. This cutting structure can ensure that the 100-iliac vein stent as a whole has a great radial support force. For some blood vessels with particularly high compression, it is difficult for ordinary braided or cut stents to achieve the radial force to completely open the narrowed segment after full release. However, this type of cut stent with bridge ribs and special cutting patterns can solve this problem very well.

[0043] A 100-iliac vein stent is used to dilate a narrowed segment of the iliac vein, and a 200-vena cava filter is placed at the inferior vena cava orifice to filter thrombi. Figure 4 This is a detailed diagram of the 200-vena cava filter, mainly composed of: 201-support frame, 202-top filter, 204-claw, 205-illuminating ring, 206-large support ring, and 208-connecting rod. The main body of the vena cava filter, 201-support frame and 206-large support ring, is cut from a single piece of nickel-titanium tubing, then expanded and heat-treated using expansion molds of different specifications to form a tapered structure that is wider at the top and narrower at the bottom. This process simplifies manufacturing steps, reduces welding, and results in a very stable overall structure, facilitating the subsequent pushing of the vena cava filter in the delivery system. The 202-top filter is woven from nickel-titanium wire wound around the 206-large support ring as fixing points. The diameter of the woven wire ranges from 0.1mm to 1mm, and the mesh size can be adjusted according to the patient's age and condition assessment. Fresh, soft thrombi can easily escape through the mesh openings, requiring smaller mesh sizes. Older, detached thrombi have a layer of harder collagen on their surface, making them less likely to escape. Therefore, larger mesh sizes can be designed to prevent excessive thrombus buildup from clogging the 202-top filter and affecting normal blood flow. The 202-top filter can also be heat-treated into a hemispherical shape; this three-dimensional structure allows thrombi to concentrate together without obstructing blood flow through the side mesh openings. If the filter collects too many thrombi, affecting normal blood flow, thrombolysis can be performed. For individuals with contraindications to thrombolysis, the vena cava filter can be directly retrieved. Figure 7 In another embodiment, 202-the top filter is a 209-filter groove cut from a nickel-titanium sheet. The 209-filter groove can be cut into different shapes to take into account the hemodynamics of the inferior vena cava, for example... Figure 7 The 209 elongated grooves facilitate blood flow while also filtering out blood clots. The cut nickel-titanium plates can be fixed to the 206 large support ring using laser welding or other anchoring techniques.

[0044] In another embodiment, see Figure 5 , Figure 6The 201-support frame also has a 203-peripheral filter, which has the same structure as the 202-top filter and is fixed to the 207-small support ring. This is because some patients have tortuous inferior vena cava segments. After the vena cava filter is fully released, there is a large uneven gap between the 202-top filter and the tortuous vein wall, and captured thrombi may escape through this gap. Adding the 203 peripheral filter allows for better conformity to the vessel wall and helps to contain captured thrombi, preventing them from moving to the edge of the 206-large support ring and escaping through the gap. Figure 5 This is a schematic diagram of the combination of the vena cava filter and the iliac vein in an embodiment.

[0045] See Figure 4 204-Claw is the anchoring system for the vena cava filter, and it shares the same nickel-titanium tube as 201-Support. The middle section, 208-Connecting Rod, is the main body of the nickel-titanium tube. 204-Claw is laser-cut into 2-4 segments and shaped into semi-circular hooks using tooling. After heat treatment, it possesses extremely high elasticity. Figure 8 After the 204-claw fully expands, the several claw flaps rotate in different directions in a semi-circular hook shape, resembling an open flower. This structure ensures that the entire claw will not detach from the 104-fixing ring. Furthermore, the claw can rotate within the fixing ring, thereby causing the vena cava filter to rotate. The 208-connecting rod is relatively slender and can move back and forth within the 104-fixing ring. After reaching its maximum distance, it is blocked by the 204-claw and the 201-support frame. Therefore, the entire vena cava filter can move back and forth and rotate with the blood flow. During the self-movement process, the 206-large support ring remains in contact with the vessel wall, ensuring that thrombi do not escape from the gaps in the vessel wall. This self-moving structure keeps the vena cava filter in a constantly active state, preventing the metal parts from undergoing endothelialization with the vessel wall and increasing the filter's retention time in the body.

[0046] The 204-claw is made of shape memory metal and has excellent self-expansion properties. Therefore, the delivery system does not require additional dilation devices, such as balloon dilation. Simply pass the 200-vena cava filter through the 402-delivery catheter through the 104-fixation ring, locate it to the 205-contrast ring using angiography, and then withdraw the delivery catheter to release the 200-vena cava filter in the blood vessel. Adjust the release position so that the 208-connecting rod is in the 104-fixation ring position, and fully release the 200-vena cava filter. The 204-claw self-expands and opens, allowing it to be dynamically anchored by being held in place by the fixation ring at the 208-connecting rod position. The filter needs to be retrieved later. The 402 delivery catheter needs to re-enter the blood vessel, pass through the 104 fixing ring, and release the 401 retrieval device. The 401 retrieval device hooks onto the 204 claw and retracts into the 402 delivery catheter. The 204 claw is compressed and reduced in size, along with the 501 thrombus covered by the 202 top filter mesh. Finally, it is completely retrieved into the 402 delivery catheter. The 402 catheter then retracts and exits from the 104 fixing ring, and is then completely withdrawn from the blood vessel, successfully completing the retrieval of the 200 vena cava filter. Figure 9 The stent is delivered through a blood vessel into the 100-iliac vein, with the tip tip passing through the 104-fixation ring. Figure 10 : Withdraw the 402 delivery catheter, and begin releasing the 200-vena cava filter; Figure 11 : The 200-vena cava filter is fully released, and the 204 claws self-expand and pass through the 104-fixation ring for dynamic anchoring; Figure 12 Release the 401 retrieval device through the 402-delivery catheter, hook the 204-claw and retract it into the 402-delivery tube to complete the retrieval of the 200-vena cava filter.

[0047] The 205-contrast ring is made of high-density metals such as platinum and tan, and is welded to the proximal end of the 208-connecting rod, near the 204-clamp position. It is used for positioning the 204-clamp during angiography in the surgical procedure.

[0048] In another embodiment, the 200-vena cava filter undergoes drug elution, particularly the 206-large support ring and 201-support frame, which require a high drug adhesion rate. Laser-etched grooves can be used on the metal surface to store and contain the drug. The drug used primarily has anti-intima hyperplasia effects, ensuring the vena cava filter remains in the body for an extended period without endothelialization of the metal surface against the vessel wall. The eluting drug is an anti-intima hyperplasia sustained-release drug or a drug-release polymer, such as rapamycin or paclitaxel.

[0049] In another embodiment, the vena cava filter is entirely constructed of biodegradable materials. These materials include, but are not limited to, polyglycolic acid (PGA), polylactic acid (PLA), and polylactic-glycolic acid copolymer (PLGA). After this biodegradable filter is anchored to the iliac vein stent, it ensures the filtration of thrombi flowing into the vena cava during the postoperative thrombotic period. During this time, the patient takes thrombolytic drugs. After a certain recovery period, the thrombus dissolves completely, and the implanted iliac vein stent has achieved good endothelialization with the vessel wall, with most of the metal mesh encapsulated by the vessel wall, eliminating the risk of new thrombus formation. At this point, the 200-vena cava filter gradually begins to degrade until it completely disappears. This biodegradable design avoids the need for secondary filter removal, reducing the number of surgeries, patient suffering, and costs.

[0050] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. An iliac vein stent assembly, characterized in that, Composed of an iliac vein stent (100) and a vena cava filter (200), characterized in that: The iliac vein stent comprises a long branch (101), a short branch (102), barbs (103), a fixing ring (104), and a main stent (105); the stent is bifurcated; the long branch (101) and the short branch (102) are released into the left and right iliac veins, respectively, and the barbs are fixed to the main stent, which is released at the common iliac vein at the confluence of the left and right iliac veins; the barbs form an angle of 10-80 degrees with the main stent, and the barbs are in the opposite direction to the long and short branches; the fixing ring uses the vena cava filter as an anchor point to connect the vena cava filter and the iliac vein stent together to form a stent assembly; the entire iliac vein stent is made of shape memory metal, and the structure is woven or laser-engraved; The vena cava filter includes a support frame (201), a top filter screen (202), a claw (204), a contrast ring (205), a large support ring (206), and a connecting rod (208). The main support frame (201) and the large support ring (206) of the vena cava filter are cut from a single piece of shape memory metal tube and expanded and heat-treated to form a conical structure that is larger at the top and smaller at the bottom. The support frame (201) of the vena cava filter also has a peripheral filter screen (203), which has the same structure as the top filter screen and is fixed on the small support ring (207). The claw and support frame are made of the same memory metal tube. The connecting rod is the main body of the memory metal tube. The claw is laser-cut into 2-4 segments and shaped into a semi-circular hook. The claw rotates in the fixed ring. The connecting rod moves back and forth in the fixed ring. The extreme positions are limited by the claw and the support frame.

2. The iliac vein stent assembly as described in claim 1, characterized in that, The braiding density of the long branch of the stent is increased or double-layer braiding is used; the braiding length of the long and short branches of the stent is adjustable.

3. The iliac vein stent assembly as described in claim 2, characterized in that, The braiding density of the main support is adjustable; after the support is braided, it is shaped using a mold and then heat-treated and annealed.

4. The iliac vein stent assembly as described in claim 3, characterized in that, The iliac vein stent is laser-engraved from nickel-titanium tubing.

5. The iliac vein stent assembly as described in claim 1, characterized in that, The barbs are made of a biodegradable material; the biodegradable material is made into a thin film or barbed threads, which are then coated on the main support, or the threads are wound around a mesh.

6. The iliac vein stent assembly as described in claim 1, characterized in that, The top filter screen of the vena cava filter is woven from nickel-titanium wire wound around a large support ring (206) as a fixing point.

7. The iliac vein stent assembly as described in claim 1, characterized in that, The top filter of the vena cava filter is a filter groove cut from a nickel-titanium sheet, and the filter groove is cut into different shapes.

8. The iliac vein stent assembly as described in claim 1, characterized in that, The imaging ring of the vena cava filter is made of platinum or tannin and is welded to the proximal end of the connecting rod near the chuck.

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