A venous filter

Abstract

The present invention relates to a venous filter, comprising: a recovery part, a connecting part and a filter wire, the ends of a plurality of filter wires are fixed inside the connecting part, and the other side of the connecting part is connected to the recovery part; the connecting part comprises: a filter wire fixing part; the ends of the filter wires are fixedly connected to the filter wire fixing part, and the filter wire fixing part is detachably connected to the recovery part. The venous filter can intercept thrombi through the filter wires, thereby realizing the function of intercepting thrombi and preventing pulmonary embolism; it can inhibit the attachment and growth of local endothelial cells in contact with the filter wires, and reduce the incidence of a series of complications such as difficulty in removal, vascular damage or tearing due to delayed removal; by removing the recovery part, when the polymer absorbable thread at the head end of the filter wire is degraded, the umbrella-shaped filter net automatically unfolds to become a vena cava stent, thereby minimizing the influence of the filter wire on venous hemodynamics to the greatest extent, so as to reduce the risk of DVT caused by permanent intracavitary implants.

Description

Technical Field

[0001] The invention relates to the technical field of design of implantable intravascular filters in medical devices, and in particular to a venous filter. Background Art

[0002] Deep venous thrombosis (DVT) refers to the process in which blood coagulates or certain formed elements in the blood aggregate to form solid masses in the deep veins, which is common in peripheral veins. Pulmonary thromboembolism (PE) refers to a syndrome in which emboli detached from peripheral veins flow into the pulmonary circulation with the blood, blocking the blood supply to the lungs and causing heart and lung dysfunction. DVT and PE are collectively called venous thromboembolism (VTE). The incidence of VTE in the United States is about 300,000 to 600,000 cases per year. PE can cause 100,000 to 200,000 deaths in the United States each year, which is a major public health problem. In clinical practice, the incidence of sudden death due to PE is about 5%. The incidence of this disease is second only to coronary heart disease and hypertension, and the mortality rate ranks third after tumors and myocardial infarction. DVT is a high-risk factor for PE. More than 90% of emboli in PE come from the detachment of DVT in the lower limbs, especially DVT in the proximal segment above the knee. When the embolic area exceeds 50%-80% of the pulmonary artery, it is very likely to cause sudden death in patients. Studies have shown that small thrombi are unlikely to cause PE, and only when the diameter of the thrombi is larger than a certain range can it cause PE. Previous clinical studies have shown that more than 33% of patients can develop symptomatic PE after DVT in the lower limbs, and 10% of symptomatic PE is fatal; but in the actual course of the disease, most PE is asymptomatic, so the misdiagnosis and missed diagnosis rates of the disease are high, and in clinical treatment, preventing the occurrence of PE is placed in a more important position than treating PE itself.

[0003] The inferior vena cava filter (IVCF) is an implantable medical device similar to a filter, usually placed in the inferior vena cava. It can effectively prevent DVT from developing into PE by physically blocking floating thrombi. Since the appearance of the Mobin-Uddin umbrella IVCF in 1967, it has been increasingly used in clinical practice and has become one of the main measures to prevent PE. According to clinical use, three types of IVCF have emerged, which are divided into permanent, temporary and retrievable IVCF according to the time of implantation.

[0004] IVCF was originally designed for permanent implantation, but in a prospective randomized controlled trial, patients implanted with permanent IVCF were followed up for up to 8 years. The results showed that retrievable IVCF can help reduce the risk of pulmonary embolism and long-term DVT recurrence, which has promoted the development of retrievable IVCF. A large number of clinical practices have shown that the longer the retrievable IVCF is placed, the lower the success rate of removal. Therefore, in 2010, the US FDA emphasized the risks of long-term retention of retrievable filters and recommended that when pulmonary embolism prevention is no longer needed, clinicians and filter implantation physicians should be jointly responsible for filter retrieval.

[0005] IVCFs are usually placed through conventional femoral or jugular vein access. Mild complications after placement include local hematoma / thrombosis and bleeding. Among them, the complications and incidence rates after IVCF surgery are thrombosis (2% to 30%), PE recurrence after filter placement (0.5% to 6%), filter breakage (2% to 10%), filter embolism, filter displacement (2% to 10%), and IVC penetration / perforation (0% to 50%); while the main complications of retrievable IVCF during retrieval include inferior vena cava thrombosis (4.3%) and inferior vena cava injury / tear (0.88%). Delayed removal of IVCF increases the possibility of adhesion between the filter and the vascular wall, which correspondingly reduces the success rate of retrieval and increases the risk of complications. Studies have shown that adhesion of IVCF to the blood vessel wall often occurs 9-12 weeks after implantation. Currently, the removal window for most retrievable IVCFs is usually within 14 days. However, in actual clinical diagnosis and treatment, many patients are unable to remove the filter due to adhesion of vascular endothelial hyperplasia and are forced to become permanent IVCFs. As a permanent implant that remains in the body for a long time, the filter may develop complications such as tilting, displacement, embolism, breakage, and puncture of blood vessels. Therefore, it is often treated as a potential hidden danger and requires regular follow-up observation.

[0006] The mechanism of action of drugs in inhibiting the proliferation and growth of endothelial cells mainly includes interference with nucleic acid biosynthesis, destruction and interference with DNA structure and function, and interference with cell protein synthesis. Among them, endostatin is a protein that can specifically inhibit the proliferation and migration of endothelial cells, which was isolated and extracted from the culture medium of the mouse endothelioma cell line EOMA in 1997. It has a significant effect of inhibiting the proliferation and migration of endothelial cells, and can cause cell growth cycle arrest and apoptosis of endothelial cells. Its inhibitory function is specific to endothelial cells. With the continuous deepening of the study of endostatin, some researchers have confirmed that the nucleolar protein on the cell membrane surface is the receptor of endostatin. Endostatin inhibits the phosphorylation process of nucleolar protein, thereby achieving the function of inhibiting the growth of new blood vessels and tumor growth. In addition, vascular endothelial growth factor is also an important target for inhibiting the proliferation and growth of endothelial cells. The development of anti-vascular endothelial growth factor drugs has evolved from the initial pegaptanib sodium, to the monoclonal antibodies bevacizumab and ranibizumab, and then to the later antibody fusion proteins aflibercept and conboxcept. More and more anti-vascular endothelial growth factor drugs have been shown to have anti-vascular endothelial hyperplasia effects and have been shown to have therapeutic effects in clinical practice.

[0007] Currently, in the clinical treatment process for preventing PE, there is a need for a convertible inferior vena cava filter that can inhibit the attachment and growth of endothelial cells, slow down the proliferation of vascular endothelial cells at the contact site, prolong the removal time window, and after being converted into a permanent implant, can remain stably in the body and reduce related complications. Summary of the invention

[0008] In view of this, the main purpose of the present invention is to provide a venous filter that can inhibit the attachment and growth of endothelial cells, slow down the proliferation of vascular endothelial cells at the contact site, prolong the removal time window, and can stably exist in the body after being converted into a permanent implant and reduce related complications.

[0009] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0010] A venous filter comprises: a recovery member, a connecting member and filter threads, wherein the ends of a plurality of the filter threads are fixed inside the connecting member, and the recovery member is connected to the other side of the connecting member; the connecting member comprises: a filter thread fixing member; the ends of the filter threads are fixedly connected to the filter thread fixing member, and the filter thread fixing member is detachably connected to the recovery member.

[0011] In a preferred embodiment, the connecting member further comprises: a connecting hook; the filter wire fixing member and the recovery member are detachably connected via the connecting hook; one end of the connecting hook is connected to the recovery member, and the other end of the connecting hook is detachably connected to the filter wire fixing member.

[0012] In a preferred embodiment, the connecting hook comprises: an upper bending portion, a connecting portion and a lower bending portion; the upper bending portion, the connecting portion and the lower bending portion are integrally formed in sequence.

[0013] In a preferred embodiment, the upper bent portion at the upper end of the connecting hook is connected to the recovery member, and the connecting portion is slidably connected to the filter wire fixing member; the lower bent portion is provided with a cutting edge toward one side of the connecting portion, so that the recovery member pulls the connecting hook to cut the filter wire fixing member to separate the connecting hook and the filter wire fixing member.

[0014] In a preferred embodiment, the filter wire fixing member is a polymer absorbable thread, the polymer absorbable thread is wrapped and bound to the end of the filter wire, and the other end of the polymer absorbable thread is wrapped and sleeved with the connecting part of the connecting hook.

[0015] In a preferred embodiment, the recycling component includes: a recycling shell and a recycling head, one end of the recycling shell is a sealing structure; one end of the recycling head is provided with a recycling connection structure, and the other end of the recycling head is fixedly connected to the outer side of the sealing end of the recycling shell.

[0016] In a preferred embodiment, the filter wire fixing member is arranged inside the recovery shell, and the upper bent portion of the connecting hook extends out of the sealing end of the recovery shell.

[0017] In a preferred embodiment, the connecting hook is a "Z"-shaped structure, the lower bending portion is bent toward the center of the recycling shell, and the upper bending portion is integrally formed with an auxiliary hook at one end away from the connecting portion toward the side close to the recycling shell, and the auxiliary hook is relatively limitedly connected to the outer wall of the recycling shell.

[0018] In a preferred embodiment, 1 to 4 connecting hooks are provided.

[0019] In a preferred embodiment, two connecting hooks are provided, and the connecting hooks are symmetrically arranged relative to the recovery shell.

[0020] In a preferred embodiment, the number of filter filaments is 6-10.

[0021] In a preferred embodiment, each of the filter threads comprises at least two strands, one end of each filter thread is wound and fixed, the middle portion of each filter thread is separated into a mesh shape, and the other end of each filter thread is fixed by a filter thread fixing member.

[0022] In a preferred embodiment, each of the filter threads comprises two strands, and one end portion of the two filter threads are intertwined and fixedly connected with each other;

[0023] The two filter threads are separated at the middle, and each filter thread crosses and passes through a filter thread of another adjacent filter thread, so that the two filter threads are cross-wrapped together;

[0024] The other ends of the two filter threads are fixed by the filter thread fixing member.

[0025] In a preferred embodiment, a plurality of the filter threads form a filter net, and in a natural state, the maximum diameter of the filter threads opened in the filter net is 15-30 mm.

[0026] In a preferred embodiment, the diameter of each filter thread is 0.1-0.2 mm.

[0027] In a preferred embodiment, the recovery member, the connecting member and the filter wire are all made of nickel-titanium alloy.

[0028] In a preferred embodiment, the outer surface of the filter filament is modified and coated with drug-loaded nanoparticles that inhibit the attachment and growth of endothelial cells.

[0029] In a preferred embodiment, the diameter of the drug-loaded nanoparticles is 10-1000 nm.

[0030] In a preferred embodiment, the drug-loaded nanoparticles include: drug particles, an inner shell and an outer shell, wherein the inner shell wraps the outside of the drug particles, the outer shell wraps the outside of the inner shell, and the outer shell is coated and connected to the surface of the filter wire.

[0031] In a preferred embodiment, the shell is composed of any one, two or more than three of polylactic acid-glycolic acid copolymer, polycaprolactone, and polylactic acid-glycolic acid.

[0032] In a preferred embodiment, the inner shell is composed of any one, two or three of butyl stearate, polylactic acid-glycolic acid copolymer, polyallylamine and polyethyleneimine.

[0033] In a preferred embodiment, the drug particles are composed of any one, two, three or four of fibroblast growth factor receptor inhibitor, recombinant human endostatin, paclitaxel and 5-fluorouracil.

[0034] In a preferred embodiment, the preparation method of the drug-loaded nanoparticles is to adopt an O / W homogenization emulsification method:

[0035] Follow these steps:

[0036] preparing a drug particle component solution with a concentration of 1%-8% g / ml;

[0037] The polylactic acid-co-glycolic acid is dissolved in dichloromethane to form a polylactic acid-co-glycolic acid oil phase;

[0038] The drug particle component solution and butyl stearate are dispersed in the polylactic acid-glycolic acid copolymer oil phase to prepare the drug-containing oil phase;

[0039] Add 0.1-1% polyvinyl alcohol solution to the drug-containing oil phase;

[0040] Centrifuge and homogenize at 1000-10000 rpm for 1 min;

[0041] Add rotor magnetic stirring for 4 h;

[0042] Collect the microsphere solution by centrifugation;

[0043] The microspheres were rinsed three times with deionized water to remove the residual polyvinyl alcohol solution and the drugs adsorbed on the surface of the microspheres;

[0044] Transfer the concentrated microsphere solution to a vial;

[0045] The drug particles containing the inner shell are produced after freeze drying in a freeze dryer;

[0046] The inner shell-containing drug particles are added dropwise to a colostrum solution formed by a dichloromethane solution containing 5-20% of the outer shell raw material under ultrasonic conditions; 0.05-2% carboxymethyl chitosan solution is added dropwise to the colostrum solution as an external aqueous phase under ultrasonic conditions to obtain a double emulsion solution;

[0047] Under electromagnetic stirring conditions, the organic solvent in the emulsion solution is volatilized for 1-8 hours, and then the solidified drug-loaded nanoparticles are obtained after centrifugation, washing and freeze-drying.

[0048] In a preferred embodiment, the method of coating the drug-loaded nanoparticles on the surface of the filter wire to obtain the nickel-titanium metal filter wire is:

[0049] The nickel-titanium metal filter wire is subjected to surface mechanical polishing treatment;

[0050] In methanol solution, use ultrasonic cleaning for 1min-20min;

[0051] Rinse with deionized water and dry with compressed air;

[0052] The dried nickel-titanium metal filter is placed in a steady-state electron cyclotron resonance plasma generating device, and the vacuum degree is adjusted to 1-10×10-3Pa, and maintained for 10-30min;

[0053] Diethylene glycol dimethyl ether is introduced, the gas pressure is maintained at 10-50 Pa, the frequency of the microwave plasma is 1-5 GHz, and the reaction is stopped after 1-20 minutes; a nickel-titanium metal filter having a large number of C=O, O-C=O and O-CO-O chemical bonds on the surface is obtained;

[0054] Through copolymerization reaction, drug-loaded nanoparticles are coated on the surface of nickel-titanium metal filter in the form of chemical bonds; thus, nickel-titanium metal filter coated with drug-loaded nanoparticles that inhibit the attachment and growth of endothelial cells is obtained.

[0055] The venous filter of the present invention has the following beneficial effects:

[0056] The venous filter comprises: a recovery part, a connecting part and filter threads, the ends of a plurality of filter threads are fixed inside the connecting part, and the recovery part is connected on the other side of the connecting part; the connecting part comprises: a filter thread fixing part; the ends of the filter threads are fixedly connected to the filter thread fixing part, and the filter thread fixing part and the recovery part are detachably connected.

[0057] The venous filter can intercept thrombi through the filter wire, so that the venous filter (which can be an inferior vena cava filter) can intercept thrombi and prevent pulmonary embolism; by performing surface modification treatment of the outer surface of the nickel-titanium alloy filter wire with drug-loaded nanoparticles, the attachment and growth of local endothelial cells in contact with the filter wire can be inhibited, and the incidence of a series of complications such as difficulty in removal, vascular damage or tearing due to delayed removal can be reduced; by removing the recovery part, when the polymer absorbable thread at the head end of the filter wire is degraded, the umbrella-shaped filter mesh automatically unfolds and becomes a vena cava stent, thereby minimizing the influence of the filter wire on venous hemodynamics to the greatest extent, so as to reduce the risk of DVT caused by permanent intracavitary implants; the present invention is highly practical and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a schematic structural diagram of a venous filter according to an embodiment of the present disclosure;

[0059] Figure 2 for Figure 1 A top view of a venous filter according to an embodiment of the present disclosure is shown;

[0060] Figure 3 for Figure 1 A partial cross-sectional view of a connector of a venous filter according to an embodiment of the present disclosure is shown;

[0061] Figure 4 It is a schematic diagram of the structure of drug-loaded nanoparticles and filter wire coating states of a venous filter according to one embodiment of the present disclosure.

[0062]

Main component symbol description

[0063] 1. Recycling parts, 11. Recycling shells, 12. Recycling heads;

[0064] 2. Connecting piece, 21. Filter wire fixing piece;

[0065] 22. connecting hook, 221. upper bending portion, 222. connecting portion, 223. lower bending portion, 224. auxiliary hook;

[0066] 3. Filter wire;

[0067] 4. Drug-loaded nanoparticles, 41. Drug particles, 42. Inner shell, 43. Outer shell. DETAILED DESCRIPTION

[0068] The venous filter of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments of the present invention.

[0069] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0070] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0071] The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or elements is not necessarily limited to those steps or elements explicitly listed but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0072] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0073] like Figure 1 to Figure 4 As shown, the venous filter includes: a recovery part 1 that can be detachably connected to the interventional device; a connector 2 that fixes the end of the filter filament 3 and ensures that it can be separated from the recovery part 1 (when the recovery part 1 is recovered, the filter filament 3 can be left inside the human body to avoid the filter filament adhering to the blood vessel and making it difficult to separate the filter filament 3); and a filter filament 3 that filters the thrombus in the blood vessel. The ends of multiple filter filaments 3 are fixed inside the connector 2, and the other end of the filter filament 3 is supported and hooked with the inner wall of the blood vessel to be filtered, so that the filter filament 3 is opened with the connector as the center to form a filter net. In order to facilitate intervention, the recovery part 1 is connected to the other side of the connector 2.

[0074] Preferably, the venous filter is an inferior vena cava filter, which can be placed in the inferior vena cava between below the opening of the human renal vein and above the bifurcation of the iliac vein.

[0075] In order to facilitate the fixing of the filter 3 and ensure that the filter 3 can be separated from the recovery unit 1, the connection unit 2 includes: a filter fixing unit 21; the end of the filter 3 is fixedly connected to the filter fixing unit 21, and the filter fixing unit 21 is detachably connected to the recovery unit 1.

[0076] Preferably, the recovery member 1 is a recovery hook, that is, the recovery member 1 is a rod-shaped structure, a notch is provided on one side wall of the recovery member 1, and the end of the notch away from the filter wire 3 is a hook-shaped structure, that is, a filter wire mesh with an umbrella-shaped structure is formed.

[0077] In order to conveniently separate the filter 3 from the recovery member 1, especially in the process of vascular interventional surgery, the connector 2 also includes a connecting hook 22; the filter fixing member 21 and the recovery member 1 are detachably connected through the connecting hook 22. One end of the connecting hook 22 is connected to the recovery member 1, and the other end of the connecting hook 22 is detachably connected to the filter fixing member 21.

[0078] Furthermore, since it is not convenient to separate the filter fixing member 21 during the interventional surgery inside the blood vessel, in order to separate the filter fixing member 21 from the connecting hook during the interventional surgery. The connecting hook 22 includes: an upper bending portion 221, a connecting portion 222 and a lower bending portion 223; the upper bending portion 221, the connecting portion 222 and the lower bending portion 223 are integrally formed in sequence;

[0079] The upper bending portion 221 at the upper end of the connecting hook 22 is connected to the recovery component 1 (it can be snap-connected, or it can be overlapped on the surface of the recovery component 1 through the bending of the upper bending portion 221 to limit the position of the entire connecting hook 22), and the connecting portion 222 is slidingly connected to the filter wire fixing component 21 (to avoid excessive connection strength and difficulty in separation, a sliding connection is selected, and it can be easily cut through the lower bending portion 223, thereby realizing the separation between the connecting hook 22 and the filter wire fixing component 21); the lower bending portion 223 is provided with a cutting edge toward one side of the connecting portion 222, so that the recovery component 1 pulls the connecting hook 22 to cut the filter wire fixing component 21 to separate the connecting hook 22 from the filter wire fixing component 21.

[0080] The filter wire fixing part 21 can be of various structures, but its material is selected to be able to melt in the blood, ensuring that it melts within a set time after separation, and loosens the constraint on the filter wire 3. Then the structure of the filter wire 3 is stretched out to be cylindrical; that is, the filter wire mesh of the original umbrella-shaped structure is loosened at the end of the filter wire fixing part 21, and the filter wire 3 is stretched out to be a cylindrical structure, which can further support the vein and form a venous stent, which not only avoids obstruction to the blood (forming thrombus and other defects), but also can ensure that the influence of the filter wire on the venous hemodynamics is minimized to the greatest extent, so as to reduce the risk of DVT caused by permanent intracavitary implants.

[0081] Preferably, the filter fixing part 21 is a polymer absorbable line. The composition of the polymer absorbable line is: medical suture made of polymer materials such as polyglycolic acid, polylactic acid, and polydioxanone. (When the venous filter is working (by adjusting the composition, the length of time that it is not explained is controlled), the polymer line does not degrade, and it needs to maintain a certain mechanical strength to play a role of firm connection. The effect of regular degradation can be achieved by adjusting the ratio of the polymer absorbable components, that is, the degradation begins after the patient passes the dangerous period. For example: it can be set to start degradation one year after implantation). The polymer absorbable line is wrapped around the end of the filter 3 (to ensure the binding connection fixing strength, thereby ensuring that the filter 3 can work stably during the umbrella-shaped net working process and ensure the filtering effect on thrombus); the other end of the polymer absorbable line is wrapped around the connecting part 222 of the connecting hook 22 (the sleeve is used to ensure that the filter 3 and the connecting part 222 can slide relative to each other and reduce the friction between each other; and then it can be smoothly cut by the blade of the lower bending part 223, thereby realizing the separation between the filter 3 and the filter fixing part 21).

[0082] In order to wrap the filter wire fixing part 21 and the connecting hook to ensure the smoothness of the intervention process. The recovery part 1 includes: a recovery shell 11 that wraps the end of the filter wire 3, the filter wire fixing part 21, and the connecting hook 22; and a recovery head 12 that is connected to the intervention device to facilitate intervention placement and recovery operations. In order to facilitate the connection with the recovery head 12, one end of the recovery shell 11 is a sealing structure. One end of the recovery head 12 is provided with a recovery connection structure (i.e., a notch structure), and the other end of the recovery head 12 is fixedly connected to the outer side of the sealing end of the recovery shell 11.

[0083] The filter fixing member 21 is arranged inside the recovery shell 11, and the upper bending part 221 of the connecting hook 22 extends out of the sealing end of the recovery shell 11; the connection between the upper bending part 221 and the recovery shell 11 is ensured, and a certain relative rotation is allowed, but it cannot fall off.

[0084] Preferably, the connecting hook 22 is a "Z"-shaped structure, which is more reasonable and reduces the space occupied by the recycling shell 11. That is, the lower bending portion 223 is bent toward the center of the recycling shell 11, and the end of the upper bending portion 221 away from the connecting portion 222 is integrally formed with an auxiliary hook 224 toward the side close to the recycling shell 11, and the auxiliary hook 224 is relatively limitedly connected to the outer wall of the recycling shell 11 (the position of the auxiliary hook 224 is limited by the outer wall of the recycling shell 11 to ensure that the connecting hook 22 and the recycling shell 11 are not separated), and the auxiliary limiting effect is to prevent the upper bending portion 221 from falling off from the recycling shell 11.

[0085] In order to ensure the connection strength with the recovery shell 11 and further ensure that the filter wire 3 can be conveniently controlled during the intervention placement process to ensure the success rate of the operation, the number of the connection hooks 22 is 1-4.

[0086] Taking into account the size and stability of the interventional device, preferably, two connecting hooks 22 are provided, and the connecting hooks 22 are symmetrically arranged relative to the recovery shell 11 to ensure stable fixation of the filter wire 3, thereby ensuring the size of the interventional device and reducing damage to the patient's blood vessels.

[0087] In order to ensure the proper density of the filter screen of the umbrella-shaped structure, the thrombus can be filtered and the normal blood circulation can be ensured. The filter wire 3 includes 6-10 wires.

[0088] In order to ensure the rationality of the structure and improve the overall strength of the filter screen structure, each filter wire 3 includes at least two strands, one end of each filter wire 3 is wound and fixed (to ensure the fixing strength, winding and fixing connection), the middle part of each filter wire 3 is separated into a grid shape, and multiple grids form a mesh structure, and the other end of each filter wire 3 is fixed by a filter wire fixing member 21. Then, a filter screen with an umbrella-shaped (umbrella surface) structure is formed, and the groove of the umbrella surface is the flow-facing surface (facing the blood flow direction).

[0089] Preferably, each filter wire 3 includes two strands, one end of which is intertwined and fixedly connected. The two filter wires are separated at the middle position, and each filter wire crosses and passes through a filter wire of another adjacent filter wire, so that the two filter wires are cross-sheathed together; that is, the mesh formed by each filter wire is sheathed together to ensure the strength of the entire filter net. The other ends of the two filter wires are fixed by a filter wire fixing member 21.

[0090] Preferably, in order to adapt to the size of the inferior vena cava of the human body, a plurality of filter threads 3 form a filter net, and the maximum diameter of the filter thread middle part in the filter net under the natural state is 15-30mm.

[0091] Preferably, the maximum diameter of the filter thread 3 is 25 mm. Preferably, the diameter of each filter thread 3 is 0.1-0.2 mm.

[0092] In order to meet the requirements of placement and retrieval of venous filters during interventional surgery, the retrieval component 1, the connector 2 and the filter wire 3 are all made of nickel-titanium alloy.

[0093] In order to achieve the purpose of a venous filter: inhibiting the attachment and growth of local endothelial cells in contact with the filter wire, reducing the incidence of a series of complications such as difficulty in removal due to delayed removal (adhesion of the filter net to the inner wall of the blood vessel), vascular damage or tearing, etc.; the outer surface of the filter wire 3 is modified and coated with drug-loaded nanoparticles 4 that inhibit the attachment and growth of endothelial cells.

[0094] Preferably, the outer surfaces of the recovery member 1 and the connection member 2 are modified and coated with drug-loaded nanoparticles 4 that inhibit the attachment and growth of endothelial cells.

[0095] Preferably, the diameter of the drug-loaded nanoparticles 4 is 10-1000 nm.

[0096] like Figure 4 As shown, in order to achieve the inhibition of drugs (polymer nanoparticles loaded with drugs that inhibit endothelial cell growth), the drug-loaded nanoparticles 4 can be coated on the surface of the nickel-titanium alloy; the drug-loaded nanoparticles 4 include: drug particles 41 (polymer nanoparticles loaded with drugs that inhibit endothelial cell growth), an inner shell 42 and an outer shell 43, the inner shell 42 wraps the outside of the drug particles 41, the outer shell 43 wraps the outside of the inner shell 42, and the outer shell 43 is coated and connected to the surface of the filter wire 3.

[0097] Preferably, the shell 43 is composed of any one, two, or more than three of polylactic acid-co-glycolic acid (PLGA), polycaprolactone, and polylactic acid-glycolic acid.

[0098] Preferably, the inner shell 42 is composed of any one, two or three of butyl stearate, polylactic acid-glycolic acid copolymer, polyallylamine and polyethyleneimine.

[0099] Preferably, the drug particles 41 are composed of any one, two, three or four of fibroblast growth factor receptor inhibitor, recombinant human endostatin, paclitaxel and 5-fluorouracil.

[0100] In one embodiment, the preparation method of the drug-loaded nanoparticles 4 is to adopt an O / W homogenization emulsification method:

[0101] Follow these steps:

[0102] preparing a drug particle component solution with a concentration of 1%-8% g / ml;

[0103] The polylactic acid-co-glycolic acid is dissolved in dichloromethane to form a polylactic acid-co-glycolic acid oil phase;

[0104] The drug particle component solution and butyl stearate are dispersed in the polylactic acid-glycolic acid copolymer oil phase to prepare the drug-containing oil phase;

[0105] Add 0.1-1% polyvinyl alcohol solution to the drug-containing oil phase;

[0106] Centrifuge and homogenize at 1000-10000 rpm for 1 min;

[0107] Add rotor magnetic stirring for 4 h;

[0108] Collect the microsphere solution by centrifugation;

[0109] The microspheres were rinsed three times with deionized water to remove the residual polyvinyl alcohol solution and the drugs adsorbed on the surface of the microspheres;

[0110] Transfer the concentrated microsphere solution to a vial;

[0111] After freeze drying in a freeze dryer, drug particles 41 containing an inner shell 42 are produced;

[0112] The drug particles 41 containing the inner shell 42 are added dropwise to a colostrum solution formed by a dichloromethane solution containing 5-20% of the shell raw material under ultrasonic conditions; 0.05-2% carboxymethyl chitosan solution is added dropwise to the colostrum solution as an external aqueous phase under ultrasonic conditions to obtain a double emulsion solution;

[0113] Under electromagnetic stirring conditions, the organic solvent in the emulsion solution is volatilized for 1-8 hours, and then the solidified drug-loaded nanoparticles 4 are obtained after centrifugation, washing and freeze-drying.

[0114] In one embodiment, the method of coating the drug-loaded nanoparticles 4 on the surface of the filter wire 3 to obtain the nickel-titanium metal filter wire is:

[0115] The nickel-titanium metal filter wire is subjected to surface mechanical polishing treatment;

[0116] In methanol solution, use ultrasonic cleaning for 1min-20min;

[0117] Rinse with deionized water and dry with compressed air;

[0118] The dried nickel-titanium metal filter was placed in a steady-state electron cyclotron resonance plasma generator and the vacuum degree was adjusted to 1-10×10 -3 Pa, maintain for 10 to 30 minutes;

[0119] Diethylene glycol dimethyl ether is introduced, the gas pressure is maintained at 10-50 Pa, the frequency of the microwave plasma is 1-5 GHz, and the reaction is stopped after 1-20 minutes; a nickel-titanium metal filter having a large number of C=O, O-C=O and O-CO-O chemical bonds on the surface is obtained;

[0120] Through copolymerization reaction, the drug-loaded nanoparticles 4 are coated on the surface of the nickel-titanium metal filter in the form of chemical bonds; thus, the nickel-titanium metal filter coated with the drug-loaded nanoparticles that inhibit the attachment and growth of endothelial cells is obtained.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A venous filter, characterized in that: include: A recovery member (1), a connecting member (2) and a filter thread (3), wherein the ends of a plurality of the filter threads (3) are fixed inside the connecting member (2), and the recovery member (1) is connected to the other side of the connecting member (2); The connecting member (2) comprises: a filter thread fixing member (21); the end of the filter thread (3) is fixedly connected to the filter thread fixing member (21), and the filter thread fixing member (21) is detachably connected to the recovery member (1); The connecting member (2) further comprises: a connecting hook (22); the filter thread fixing member (21) and the recovery member (1) are detachably connected via the connecting hook (22); One end of the connecting hook (22) is connected to the recovery component (1), and the other end of the connecting hook (22) is detachably connected to the filter thread fixing component (21); The connecting hook (22) comprises: an upper bending portion (221), a connecting portion (222) and a lower bending portion (223); the upper bending portion (221), the connecting portion (222) and the lower bending portion (223) are integrally formed in sequence; The upper bent portion (221) at the upper end of the connecting hook (22) is connected to the recovery member (1), and the connecting portion (222) is slidably connected to the filter fixing member (21); the lower bent portion (223) is provided with a cutting edge toward one side of the connecting portion (222), so that the recovery member (1) pulls the connecting hook (22) to cut the filter fixing member (21) to separate the connecting hook (22) from the filter fixing member (21); The number of the connecting hooks (22) is 1 to 4.

2. The venous filter according to claim 1, characterized in that The filter thread fixing member (21) is a polymer absorbable thread, which is wrapped around and bound to the end of the filter thread (3), and the other end of the polymer absorbable thread is wrapped around and sleeved with the connecting portion (222) of the connecting hook (22).

3. The venous filter according to claim 2, characterized in that The recycling unit (1) comprises: a recycling shell (11) and a recycling head (12); one end of the recycling shell (11) is a sealing structure; one end of the recycling head (12) is provided with a recycling connection structure; the other end of the recycling head (12) is fixedly connected to the outer side of the sealing end of the recycling shell (11); The filter thread fixing member (21) is arranged inside the recovery shell (11), and the upper bent portion (221) of the connecting hook (22) extends out of the sealed end of the recovery shell (11).

4. The venous filter according to claim 3, characterized in that The connecting hook (22) is a "Z"-shaped structure, the lower bent portion (223) is bent toward the center of the recovery shell (11), and an auxiliary hook (224) is integrally formed on the side of the upper bent portion (221) away from the connecting portion (222) and close to the recovery shell (11), and the auxiliary hook (224) is relatively limitedly connected to the outer wall of the recovery shell (11).

5. The venous filter according to claim 1, characterized in that Two connecting hooks (22) are provided, and the connecting hooks (22) are symmetrically arranged relative to the recovery shell (11).

6. The venous filter according to any one of claims 1 to 5, characterized in that: The outer surface of the filter thread (3) is modified and coated with drug-loaded nanoparticles (4) that inhibit the attachment and growth of endothelial cells.

7. The venous filter according to claim 6, characterized in that The drug-loaded nanoparticles (4) comprise: drug particles (41), an inner shell (42) and an outer shell (43); the inner shell (42) wraps the outside of the drug particles (41); the outer shell (43) wraps the outside of the inner shell (42); and the outer shell (43) is coated and connected to the surface of the filter filament (3).

Images