Vena cava filter capable of being automatically degraded

Abstract

The utility model discloses an automatic degradable vena cava filter which comprises a filter body made of degradable materials, the filter body is provided with at least three supporting strips distributed in an array mode in the circumferential direction, the upper end and the lower end of each supporting strip are connected into a whole, the supporting strips are elastic, and the supporting strips can be automatically degraded under the condition that the supporting strips are not restrained by external force. Each supporting strip is of an arc-shaped structure with the middle protruding outwards. The utility model has the advantages of stable structure, convenient installation, little contact with the blood vessel wall, no inflammation, automatic degradation after several months, and no need of secondary operation to take out.

Description

TECHNICAL FIELD

[0001] The utility model relates to medical equipment technical field, concretely relates to a kind of automatically degradable vena cava filter. BACKGROUND

[0002] Pulmonary embolism is the thrombus of peripheral vein drop into pulmonary circulation, block pulmonary artery or its branch, cause pulmonary circulation disorder disease, pulmonary embolism is the higher clinical morbidity, mortality acute, its morbidity is only less than coronary heart disease and hypertension, when embolism area exceeds 50%-80% of pulmonary artery, it is extremely easy to cause sudden death, accounts for 5% of clinical sudden death incidence, mortality is only less than tumor and myocardial infarction.75%-90% of pulmonary embolism in pulmonary embolism is derived from deep vein thrombosis, including deep vein thrombosis of lower extremity and thrombus in pelvic venous plexus.Clinically, high-risk patients with pulmonary embolism with anticoagulation contraindication or ineffective anticoagulation need to be implanted into inferior vena cava filter to intercept the thrombus, to prevent it from entering the pulmonary circulation, and the vena cava filter has become the main method for preventing pulmonary embolism caused by deep vein thrombosis in clinic.

[0003] Vena cava filter is implanted into inferior vena cava through interventional surgery, and is usually located between the openings of inferior vena cava and renal vein. This position helps to capture the thrombus formed in the lower limb vein and prevent the thrombus from entering the pulmonary artery system with blood flow, thereby preventing the occurrence of pulmonary embolism. When the vena cava filter is placed, the filter is pre-prepared in a rod-shaped recovery in a special thin tube, and is sent to the position of inferior vena cava through a special delivery pipeline. After accurate positioning, the pipeline is withdrawn, and the mesh structure is immediately expanded to support in the vein, intercepting the thrombus while the blood flow can pass normally.

[0004] The vena cava filter commonly seen in the market is divided into permanent, temporary and retrievable filters. The permanent filter is suitable for patients who need lifelong prevention of thromboembolism, long-term anticoagulation contraindication, and short expected survival time. There are long-term complications such as perforation, displacement and fracture of the metal filter. The temporary filter is temporarily implanted during the acute phase, and the filter is removed when the risk of thrombus detachment decreases. It is suitable for preventing pulmonary embolism in patients with severe trauma, but the clinical management is complex and infection is easy to occur.

[0005] The most commonly used is the retrievable filter, which prevents thromboembolism during high-risk period and removes the filter when the risk decreases. The filter is usually a mesh structure made of metal, which usually needs to be removed after three weeks of placement. If it is not removed for a long time, it is easy to integrate into the blood vessel wall, which may cause long-term complications. In the prior art, although the degradable vena cava filter can intercept thrombus during the high-risk period of pulmonary embolism and disappear automatically after the high-risk period, it can avoid many complications caused by long-term placement of metal filters in the body and avoid secondary surgery to recover the filter. However, the structure design of the current degradable filter still follows the traditional mesh stent method, which not only has the problem of inconvenient installation, but also has many contact points of the mesh multi-branch structure, which is easy to cause inflammation of the blood vessel wall. Utility model content

[0006] Therefore, the utility model provides a kind of automatically degradable vena cava filter, its purpose is to solve the technical problems of existing degradable stent indicated in background art.

[0007] To achieve the above object, the utility model technical scheme is as follows:

[0008] A kind of automatically degradable vena cava filter, including the filter body made of degradable material, it is characterized in that: the filter body has at least 3 support bars distributed in circumferential direction, each support bar upper and lower end is connected as a whole, the support bar has elasticity, under the action of no external force constraint, each support bar is all arc configuration with middle part outwardly convex.

[0009] With the above structure, simple structure, easy to install, less contact with blood vessel wall will not produce inflammation, less pain, can be automatically degraded after several months, without secondary surgery to remove.

[0010] As preferred: twist the filter body, each support bar can be helically deformed into long strip type rod structure. With the above structure, the filter body is placed in blood vessel after being twisted, and is automatically expanded after the external force is removed, which is simple in structure and easy to install.

[0011] As preferred: each support bar is integrally formed, and the number of support bars is 3, 4 or 5. With the above structure, the blood thrombus is effectively intercepted while ensuring the normal flow of blood.

[0012] As preferred: the middle outer side of the support bar is provided with anti-displacement barb, and the anti-displacement barb is inserted into the inner wall of blood vessel. With the above structure, the support bar is fixed to prevent displacement.

[0013] As preferred: the anti-displacement barb is arrayed along the length direction of the support bar, and the upper anti-displacement barb is inclinedly arranged in the opposite direction relative to the lower anti-displacement barb; the middle anti-displacement barb extends outwardly along the horizontal direction. With the above structure, the displacement of the filter body is limited in multiple directions, which is simple in structure and stable.

[0014] As preferred: the support bar has deformation section at both ends and positioning section at the middle part, the material hardness of the positioning section is greater than that of the deformation section, and the positioning section is in linear segment structure under the action of no external force constraint. With the above structure, the deformation section at both ends is deformed to form rod structure after the filter body is twisted, which is easy to install, the contact area between the filter and the inner wall of blood vessel is larger, and the filter is more stable.

[0015] As preferred: the positioning section and the deformation section are formed by double-color injection molding. With the above structure, production and manufacture are facilitated

[0016] As preferred: the filter body adopts the degradable material as polycaprolactone, polylactic acid or polyglycolide. With the above structure, good performance is achieved, and the human body is harmless.

[0017] As preferred: the filter body adopts polylactic acid material, and the number average molecular weight of the polylactic acid is 81000-87000 g / mol, and the weight average molecular weight is 157000-163000 g / mol. With the above structure, the polylactic acid has excellent tensile strength and ductility, is non-toxic and non-irritating, and can be completely degraded in a proper time.

[0018] As preferred: the filter body has a length of 60-80 mm. With the above structure, it is convenient to place, and the thrombus interception effect is good.

[0019] Compared with the prior art, the filter has the beneficial effects that:

[0020] 1. The filter is made of degradable material, can be automatically and completely degraded after several months, is safe and environmentally friendly, does not need secondary surgery for removal, and causes less pain to the patient. The filter is elastic as a whole, the filter body is twisted, each support strip can be spirally deformed into a long rod-shaped structure, and placement is convenient.

[0021] 2. The middle part of the support strip is in an outwardly convex arc-shaped structure or a straight segment structure, is supported on the inner wall of the blood vessel, and can effectively intercept thrombus. The number of support strips is 3, 4 or 5, and there is sufficient gap between each support strip to ensure effective interception of thrombus while normal blood flow.

[0022] 3. The middle part of the support strip is provided with a plurality of anti-displacement barbs, the upper anti-displacement barb is inclined in the opposite direction relative to the lower anti-displacement barb, the movement of the filter in the blood vessel is limited upward and downward, the filter can be better fixed, and displacement of the filter is prevented. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structural schematic view of the filter body A of the filter with 3 support strips 1.

[0024] Figure 2 It is a schematic view showing the layout of the 3 support strips 1.

[0025] Figure 3 It is a schematic view of the filter body A of the filter with 3 support strips 1 supported in the blood vessel 2.

[0026] Figure 4 It is a schematic view of the filter body A in a twisted state.

[0027] Figure 5 It is a schematic view when the filter body A is placed.

[0028] Figure 6A schematic diagram showing the orientation of the anti-displacement barb 1a in Example 1;

[0029] Figure 7 Schematic diagram of the structure of the filter body A with four support bars;

[0030] Figure 8 A schematic diagram showing the layout of the four support bars 1;

[0031] Figure 9 Schematic diagram of the structure of the filter body A with the middle portion of the support bar 1 being a straight line segment;

[0032] Figure 10 for Figure 9 Schematic diagram of the filter body A in the blood vessel 2;

[0033] Figure 11 A schematic diagram showing the orientation of the anti-displacement barb 1a in the second embodiment. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0035] like Figure 1 As shown, a self-degradable vena cava filter, the filter body A is composed of at least three elastic support bars 1, the support bars 1 are arranged in an array along the circumferential direction, and the upper and lower ends of each support bar 1 are connected as a whole. In the natural state, the middle part bulges outward and is used to support the inner wall of the blood vessel 2.

[0036] Based on the above structure, since the support bar 1 of the filter body A is elastic, the filter body A can be twisted to form a spiral long rod-shaped structure to facilitate the placement of the vena cava filter into the patient's blood vessels; after the vena cava filter is placed in the patient's blood vessels, the twisting restraint on the filter body A is released, and the filter body A can return to its original shape by relying on its own elastic force. Figure 3 The state shown is that the middle portion of each support bar 1 is supported on the inner wall of the blood vessel 2, thus completing the installation of the filter. After the filter body A is installed, the hollow structure formed by its lower end and the middle portion of each support bar 1 can effectively intercept blood clots, and the effect of intercepting blood clots is relatively good.

[0037] The filter body A is made of degradable material polycaprolactone, polylactic acid or polyglycolide, and the polylactic acid material with excellent tensile strength and ductility is optimal. Since the degradable material is used, it can be completely degraded automatically after a few months, which is safe and environmentally friendly, and does not need to be removed by secondary surgery. In this embodiment, the number average molecular weight of polylactic acid is 81000-87000 g / mol, and the optimal value is 84000 g / mol; the weight average molecular weight is 157000-163000 g / mol, and the optimal value is 160000 g / mol. At the same time, the polylactic acid material does not produce inflammation when it is in contact with the blood vessel wall, and does not need to be removed by secondary surgery. The length of the filter body A is 60-80 mm, and the optimal value is 70 mm, which can be naturally degraded after 3-6 months.

[0038] The number of support bars 1 is preferably 3, 4 or 5, and each support bar 1 is integrally formed. After the filter body A is placed in the vena cava, the corresponding end position of the support bar 1 is located in the middle position of the blood vessel 2, and the middle part is supported on the inner wall of the blood vessel 2. Each support bar 1 can collectively form a stent to intercept thrombus. Each support bar 1 is an elongated bar, and the sufficient gap formed between them ensures the normal circulation of blood. After the filter body A is installed, the hollow structure surrounded by the lower end of the filter body A and each support bar 1 can effectively intercept thrombus, achieve filtration, and the better the effect of intercepting thrombus, the worse the effect of normal blood flow. When the number of support bars 1 is less than 3, it cannot effectively intercept thrombus; when the number of support bars 1 exceeds 5, the gap between each support bar 1 is small, which will affect the normal flow of blood.

[0039] Embodiment one

[0040] As shown in Figure 1 and Figure 7 , under the action of external force constraint, each support bar 1 is in an arc-shaped structure with the middle part protruding outward, and the whole is in an arc shape. Figure 1 The filter body A composed of 3 support bars 1, Figure 7 The filter body A composed of 4 support bars 1. As shown in Figure 4 , the filter body A is twisted, and each support bar 1 can be spirally deformed into an elongated rod structure, as shown in Figure 5 , after the clamping rod structure is placed in the blood vessel 2, the external force is removed, and the filter body A can restore to the state shown in Figure 3 by relying on its own elastic force, as shown in Figure 2 and Figure 8 , it can be seen that the support bars 1 are uniformly distributed, and after the filter body A is placed in the blood vessel 2, the arc-shaped part of the middle part of each support bar 1 protrudes outward and supports on the inner wall of the blood vessel 2, and the radial force is uniform, which can effectively fix the filter body A.

[0041] Embodiment two

[0042] As shown in Figure 9As shown, each support strip 1 has a deformation section 11 at both ends and a positioning section 12 at the middle, the material hardness of the positioning section 12 is greater than that of the deformation section 11, under the action of no external force constraint, the positioning section 12 is in a straight section structure, by twisting the filter body A, only the deformation section 11 with smaller hardness is spirally deformed, the positioning section 12 remains unchanged, i.e. a growing strip-shaped structure is formed. Figure 10 As shown, after placing the filter body A in the blood vessel 2, the filter body A restores to the natural state, the positioning section 12 is supported on the inner wall of the blood vessel 2, and the contact area is larger and more stable than that in the first embodiment by the arc-shaped support in the middle of the support strip 1. The positioning section 12 and the deformation section 11 are formed by double-color injection molding, without assembly, integrated molding, the strength and surface quality of the filter body A are improved.

[0043] As shown, Figure 6 and Figure 11 As shown, the outer side of the middle of the support strip 1 in the first and second embodiments is provided with anti-displacement barbs 1a which are arrayed along the length direction of the support strip 1, the anti-displacement barbs 1a are inserted into the inner wall of the blood vessel 2 to fix the filter body A. The upper anti-displacement barb 1a and the lower anti-displacement barb 1a are obliquely arranged in directions away from each other, the middle anti-displacement barb 1a extends outward along the horizontal direction and is inserted vertically into the inner wall of the blood vessel 2. In this way, the filter body A can be limited in multiple directions to prevent displacement, and the structure is simple and stable.

[0044] Finally, it should be noted that the above description is only for the preferred embodiments of the present application, and those skilled in the art can make various similar expressions under the inspiration of the present application without violating the purpose and claims of the present application, and such changes fall within the protection scope of the present application.

Claims

1. An automatically degradable vena cava filter comprising a filter body (A) made of a degradable material, characterized in that: The filter body (A) has at least three support bars (1) arranged in the circumferential direction, each of the support bars (1) is connected integrally at both ends, and the support bar (1) has elasticity and is in an arc-shaped structure with the middle part protruding outward under no external force constraint.

2. The automatically degradable vena cava filter of claim 1, wherein: Twisting the filter body (A), each of the support bars (1) can be spirally deformed into an elongated rod-shaped structure.

3. The automatically degradable vena cava filter of claim 1, wherein: Each of the support bars (1) is integrally formed, and the number of the support bars (1) is three, four or five.

4. The automatically degradable vena cava filter of claim 1, wherein: The support bar (1) is provided with a displacement-preventing barb (1a) on the outer side of the middle part, and the displacement-preventing barb (1a) is inserted into the inner wall of the blood vessel (2).

5. The automatically degradable vena cava filter of claim 4, wherein: The displacement-preventing barbs (1a) are arranged in the length direction of the support bar (1), the upper displacement-preventing barb (1a) is arranged in the opposite direction relative to the lower displacement-preventing barb (1a), and the middle displacement-preventing barb (1a) extends outward in the horizontal direction.

6. The automatically degradable vena cava filter of claim 1, wherein: The support bar (1) has a deformation section (11) at both ends and a positioning section (12) at the middle part, the material hardness of the positioning section (12) is greater than that of the deformation section (11), and the positioning section (12) is in a straight section structure under no external force constraint.

7. The automatically degradable vena cava filter of claim 6, wherein: The positioning section (12) and the deformation section (11) are formed by double-color injection molding.

8. The automatically degradable vena cava filter of claim 1, wherein: The filter body (A) is made of the degradable material, which is polycaprolactone, polylactic acid or polyglycolide.

9. The automatically degradable vena cava filter of claim 8, wherein: The filter body (A) is made of polylactic acid, the number average molecular weight of the polylactic acid is 81000-87000 g / mol, and the weight average molecular weight is 157000-163000 g / mol.

10. The automatically degradable vena cava filter of claim 1, wherein: The length of the filter body (A) is 60-80 mm.

Images