CN115500989A - Degradable vena cava filter with auxetic structure - Google Patents

Abstract

The application provides a degradable vena cava filter with an auxetic structure, which relates to the field of cardiovascular medical instruments and comprises a stent section, wherein the stent section comprises a plurality of auxetic components which are sequentially connected along the circumferential direction, each auxetic component is provided with an anchoring hook, and the anchoring hook is embedded into a vascular wall and used for positioning the filter; when the auxetic assemblies are pulled, the auxetic assemblies expand outward away from the axis. Through setting up a plurality of assemblies that expand, and then blood flow strikes when making the assembly that expands to draw, a plurality of assemblies that expand can expand respectively along radial outside and drive and correspond anchor hook and expand outward for the support section more closely laminates in the vascular wall, improves the anchoring ability of anchor hook on the vascular wall, reduces the aversion problem of degradable vena cava filter that has the structure that expands in the use.

Description

Degradable vena cava filter with auxetic structure

Technical Field

The application relates to the field of cardiovascular medical instruments, in particular to a degradable vena cava filter with an auxetic structure.

Background

Pulmonary Embolism (PE) refers to the pathological and clinical state in which blood clots lodge in the pulmonary arteries and obstruct blood flow to the rest of the lungs, the third most common cardiovascular disease following coronary heart disease and stroke. Statistically, 90% of PE patient thrombi are from Deep Vein Thrombi (DVT).

The current treatment modalities for pulmonary embolism mainly include systemic anticoagulation, local thrombolysis and thrombolysis. However, for patients who have anticoagulation contraindication or have bleeding complications during anticoagulation and thrombosis liability and who have recurrent PE, it is necessary to implant an Inferior Vena Cava Filter (IVCF) for preventing pulmonary embolism caused by DVT embolus shedding. The earliest permanent IVCF applications resulted in high complication rates due to long-term survival and required life-long dosing of patients. The current application is that recyclable IVCF is more used, but after IVCF is placed for 2 weeks, a partial filter is covered by vascular endothelium, so that the problems of short recycling window, difficult recycling and high complication rate are caused. In recent years, degradable materials have been widely used in clinic, and the degradation is a future development trend. The degradable IVCF is gradually degraded after the task of preventing pulmonary embolism is completed, so that the risks of long-term complications and secondary operation taking out can be avoided, the burden of a patient is reduced, and the prognosis is improved.

When the problem of filter displacement is a big pain point of the traditional degradable IVCF, the material of the traditional degradable IVCF can be degraded along with the use, and the filter can be pulled and contracted due to the impact of blood flow, so that the anchoring capacity of the filter can be reduced continuously, and the filter can be displaced in the use process to be improved.

Disclosure of Invention

In view of this, the embodiments of the present disclosure provide a degradable vena cava filter with an auxetic structure, which reduces the problem of displacement during the use of the filter.

The invention provides the following technical scheme: a degradable vena cava filter having an auxetic structure comprising a stent segment;

the stent section comprises a plurality of expansion assemblies which are sequentially connected along the circumferential direction, each expansion assembly is provided with an anchoring hook, and the anchoring hooks are embedded into the vessel wall for positioning the filter;

when the expansion component is pulled, the expansion component expands outwards and drives the anchoring hook to expand outwards.

Through above-mentioned technical scheme, set up a plurality of assemblies that expand, and then blood flow strikes and makes the assembly that expands when drawing, a plurality of assemblies that expand can expand along radial direction towards the direction of keeping away from the axial lead, and inseparabler laminating improves the anchoring ability of anchoring hook on the vascular wall in the vascular wall, reduces the whole aversion problem in the use of filter.

Preferably, each auxetic assembly is formed by arranging a plurality of auxetic units, and the anchoring hooks are fixed on the auxetic units.

Through above-mentioned technical scheme, it forms by a plurality of auxetic unit arrangements to set up every auxetic subassembly, and then can change the whole shape of auxetic subassembly through the configuration of adjusting the auxetic unit, improves the suitability for different vascular walls.

Preferably, the filter screen section comprises a restraining ring and a filter screen, the outer diameter of the restraining ring is smaller than the diameter of the bracket section, and the filter screen is arranged between the bracket section and the restraining ring;

the filter screen is formed by interweaving a plurality of filter wires, and each filter wire is respectively connected with the bracket section and the restraint ring.

Preferably, one end of each expansion component close to the restraint ring is provided with a limiting ring, the filter wires correspond to the limiting rings one by one, each filter wire penetrates through the corresponding limiting ring, and each filter wire is connected with the support section through the corresponding limiting ring.

Through the technical scheme, the limiting rings are arranged, so that the filter wires are connected with the limiting rings in a one-to-one correspondence mode, the offset of the filter wires relative to the support sections of the limiting rings is reduced, the rotary displacement of the filter screen sections is reduced, and the structural stability of the filter screen sections is improved.

Preferably, the material of the stent section is a degradable metal material, the material of the restraint ring and the material of the filter wire are both biodegradable polymers, and the thickness of the restraint ring is smaller than the diameter of the filter wire.

Through the technical scheme, the degradation speed of the degradable metal material is lower than that of the biodegradable polymer, so that the degradation speed of the bracket section is lower than that of the restraint ring and the filter screen, the bracket section is embedded in a body and then is subjected to endothelialization, the bracket section is wrapped, the contact area with blood is reduced, the degradation rate is further slowed down, and the degradation of the bracket section is later than that of the filter screen section, so that the integral stability can be effectively guaranteed, and the integral structure displacement and thrombus falling off are avoided;

on the other hand, because the thickness of the restriction ring is smaller than the diameter of the filter wire, when the trapped thrombus passes through the thrombolysis or thrombus removal treatment after a dangerous period, the restriction ring can be degraded earlier than the filter wire, so that the filter screen is scattered, and the smoothness of blood is restored.

Preferably, each anchoring hook is arranged obliquely in the direction of the axis of the carrier section towards the end adjacent to the filter screen section.

Through above-mentioned technical scheme for anchoring hook can be along the more stable anchoring in the vascular wall of blood flow, further strengthens holistic anchoring ability, reduces the aversion.

Preferably, the tip of each anchoring hook is of rounded configuration.

Through above-mentioned technical scheme, the pointed end that sets up anchoring hook is the radius structure, can reduce the damage of anchoring hook pointed end to the vascular wall.

Preferably, a connecting assembly is arranged between every two adjacent auxetic assemblies, and any two adjacent auxetic assemblies are connected through the connecting assembly.

Preferably, the configuration of the auxetic unit is a concave auxetic structure.

Compared with the prior art, the beneficial effects that can be achieved by the at least one technical scheme adopted by the embodiment of the specification at least comprise:

1. according to the invention, the anchoring hooks are arranged on the auxetic components, and after the stent section is impacted by blood flow, the auxetic components can expand outwards in the direction away from the axial lead, so that the anchoring hooks are more tightly attached to the vessel wall, the anchoring capability of the stent section is improved, and the problem of displacement of the whole filter in the using process is further reduced;

2. according to the invention, the plurality of expansion assemblies are arranged, so that after blood flow impacts the stent section, the plurality of expansion assemblies are respectively expanded outwards, so that the adhesion between each expansion assembly and the vascular wall is tighter, the contact area between each expansion assembly and the vascular wall is increased, and the integral inclination of the filter is reduced;

3. the support section and the filter screen section of the filter are respectively made of different degradable materials, the filter screen section is degraded firstly, and the support section is degraded later, so that stepwise and stepwise degradation is realized, the degradation rate is controlled, the function of preventing pulmonary embolism can be achieved, and complications of premature drop and long-term implantation of thrombus can be avoided.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic overall structure diagram according to a first embodiment;

FIG. 2 is a schematic view showing the overall structure of a filter according to the first embodiment;

FIG. 3 is a schematic view of an overall structure for showing a confinement ring according to the first embodiment;

fig. 4 is a schematic structural view of an auxetic unit according to a second embodiment;

fig. 5 is a schematic structural view of an auxetic unit according to a third embodiment;

FIG. 6 is a partial structural view of a stent segment according to the fourth embodiment;

fig. 7 is a partial structural schematic view of a stent section of the fifth embodiment.

Reference numerals:

1. a carrier section;

101. an auxetic assembly; 1011. an auxetic unit;

102. a connecting assembly; 1021. a connection unit;

103. an anchoring hook;

104. a limiting ring;

105. a connecting rod;

2. a filter screen segment;

201. filtering with a screen; 2011. filtering the silk;

202. a confinement ring.

Detailed Description

Embodiments of the present application are described in detail below with reference to the accompanying drawings.

The following embodiments of the present application are described by specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. The application is capable of other and different embodiments and its several details are capable of modifications and various changes in detail without departing from the spirit of the application. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present application, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number and aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should be further noted that the drawings provided in the following embodiments are only schematic illustrations of the basic concepts of the present application, and the drawings only show the components related to the present application rather than the numbers, shapes and dimensions of the components in actual implementation, and the types, the numbers and the proportions of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details.

The inventor finds that the traditional degradable inferior vena cava filter can be continuously impacted with blood flow, the filter stretches and contracts, the anchoring hooks are separated from the blood vessel wall, and the filter is displaced.

Based on this, the embodiments of the present specification propose a degradable vena cava filter with an auxetic structure: as shown in fig. 1, the stent comprises a stent segment 1, the stent segment 1 comprises a plurality of auxetic assemblies 101, anchoring hooks 103 are arranged on the auxetic assemblies 101, the auxetic assemblies 101 are pulled to expand outwards after being impacted by blood flow and drive the anchoring hooks 103 to expand outwards, and then the anchoring hooks 103 and the auxetic assemblies 101 are attached to the wall of a blood vessel more tightly, so that the overall anchoring capability is enhanced, and the displacement of a filter is reduced.

The technical solutions provided by the embodiments of the present application are described below with reference to the accompanying drawings.

Example one

Referring to fig. 1 and 2, a carrier section 1 and a filter screen section 2 are included. The support section 1 is annular, and the support section 1 includes a plurality of assemblies 101 that expand and a plurality of coupling assembling 102, and a plurality of assemblies 101 that expand and a plurality of coupling assembling 102 are along circumference interval distribution and fixed connection in proper order.

Each auxetic assembly 101 is composed of a plurality of auxetic units 1011 sequentially arranged along the axial direction, and the configuration of each auxetic unit 1011 is a concave type auxetic structure.

Each connecting assembly 102 is composed of a plurality of connecting units 1021 arranged in sequence along the axis direction, and the configuration of each connecting unit 1021 is an inward concave type auxetic structure.

A plurality of anchoring hooks 103 are fixed on a plurality of auxetic units 1011 in each auxetic assembly 101 at intervals along the axial direction, each anchoring hook 103 is arranged on one side of the auxetic unit 1011 away from the axial lead of the bracket segment 1, the anchoring hooks 103 are obliquely arranged towards one end close to the filter screen segment 2 along the axial lead direction of the bracket segment 1, and the included angle between each anchoring hook 103 and the axial lead of the bracket segment 1 is 45 degrees. The pointed end of anchoring hook 103 is the radius structure, and then when anchoring hook 103 imbeds the vascular wall, can effectively reduce the damage to the vascular wall.

In the in-service use, after filter screen section 2 caught the thrombus, can lead to support section 1 to receive the blood flow and strike, support section 1 receives the blood flow and strikes and can take place tensile, and tensile back can make a plurality of assemblies 101 that expand along radial outside expansion, and anchoring hook 103 removes to the vascular wall depths thereupon, and inseparabler laminating has improved holistic anchoring ability in the vascular wall, reduces the whole possibility that the phenomenon of shifting appears. And the whole back that expands outward of support section 1, support section 1 can be inseparabler with the laminating of vascular wall, and the slope of the relative vascular wall can effectually take place for support section 1 is whole to the supplementary of cooperation anchoring hook 103, improves the fixed stability of integral erection.

The filter screen segment 2 comprises a constraint ring 202 and a filter screen 201, the constraint ring 202 and the filter screen 201 are coaxially arranged with the bracket segment 1, the outer diameter of the constraint ring 202 is smaller than the diameter of the bracket segment 1, and the two axial ends of the filter screen 201 are respectively connected with the bracket segment 1 and the constraint ring 202.

Referring to fig. 2 and 3, in the present embodiment, six groups of auxetic assemblies 101 are provided, a semicircular limiting ring 104 is fixed on the auxetic unit 1011 of each group of auxetic assemblies 101 close to the filter screen 201, and an axial line of each limiting ring 104 is perpendicular to and intersects with an axial line of the filter screen 201.

In this embodiment, the filter screen 201 is formed by interweaving six filter wires 2011, the six filter wires 2011 penetrate through six limit rings 104 in a one-to-one correspondence manner, the middle section of each filter wire 2011 is located on the corresponding limit ring 104, and each filter wire 2011 is located on both sides of the corresponding limit ring 104 and is equally divided into two sides which are staggered and pressed and fixed, so that in an actual use process, the displacement of the filter wire 2011 corresponding to the limit ring 104 can be reduced, the structural stability of the filter screen 201 is improved, and the phenomenon that thrombus falls off due to the fact that the filter screen 201 rotates and deviates is effectively reduced. The six filter wires 2011 respectively penetrate through the six corresponding limiting rings 104 in the same manner and then are interwoven to form a rhombic grid, and all end points of the six filter wires 2011 are converged on the same plane and fixed on the limiting ring 202. The mesh pores on the filter screen 201 are gradually reduced from the bracket section 1 to the restraint ring 202, the minimum pore of the mesh on the filter screen 201 is 1mm, and the inner diameter of the restraint ring 202 is 1mm. In the actual process of capturing the thrombus, the filter screen 201 is arranged close to the hole at one end of the restriction ring 202, so that the interception of the thrombus with the diameter smaller than 1mm can be reduced, and the thrombus with the diameter smaller than 1mm can not cause pulmonary artery embolism even if entering the lung, so that the blockage of the filter screen 201 can be effectively reduced, and the possibility of blood flow blockage caused by the blockage of the filter screen 201 is reduced.

Referring to fig. 1 and 2, the whole stent segment 1 is made by laser cutting, and the whole stent segment 1 is made of degradable metal material, specifically magnesium alloy in this embodiment. The filter wire 2011 and the restraining ring 202 are made of biodegradable polymer, specifically PDO in this embodiment. The thickness of the confinement rings 202 is less than the diameter of the filter wires 2011.

In other embodiments, the carrier section 1 may also be made by additive manufacturing techniques.

The degradation process of the filter as a whole in this example is as follows:

s1, after the filter is integrally implanted into a body to capture thrombus and is subjected to thrombolysis or thrombus removal treatment to pass through a dangerous period, the filter wire 2011 and the restraint ring 202 made of biodegradable polymers can be degraded before the stent section 1, and because the thickness of the restraint ring 202 is smaller than the diameter of the filter wire 2011, the restraint ring 202 can be degraded before the filter wire 2011, and after the restraint ring 202 is degraded, the filter screen 201 is scattered to enable blood flow to recover smoothly and gradually degrade.

S2, the support section 1 is made by degradable metal material, play the effect of supporting the vascular wall on the one hand, on the other hand degradable metal material ' S degradation rate is less than biodegradable polymer ' S degradation rate, support section 1 is implanted internal back through endothelialization, support section 1 is wrapped up, reduce with blood area of contact, degradation rate further reduces, and then can be effectual the degradation rate of assurance support section 1 be slower than the degradation rate of filter screen 201, thereby guarantee overall structure ' S stability, reduce the emergence of whole aversion and thrombus dropout phenomenon.

Example two

The difference from the first embodiment is that, referring to fig. 4, the configuration of the auxetic unit 1011 is a rotary type auxetic structure.

EXAMPLE III

The difference from the first embodiment is that, referring to fig. 5, the configuration of the auxetic unit 1011 is a symmetrical auxetic structure.

Example four

The difference from the first embodiment is that, referring to fig. 6, the connection unit 1021 is a traditional rhombic non-auxetic unit, and the bracket section adopts a structure combining the non-auxetic unit and the auxetic unit, so that the mechanical property of the whole filter is improved while the auxetic effect is maintained.

EXAMPLE five

The difference from the first embodiment is that, referring to fig. 7, the expansion unit 1011 is fixed with the connecting rod 105, and the limiting ring 104 is disposed at an end of the connecting rod 105 far from the expansion unit 1011.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the product embodiments described later, since they correspond to the method, the description is simple, and the relevant points can be referred to the partial description of the system embodiments.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (9)

1. A degradable vena cava filter having an auxetic structure, comprising a stent section (1);

the stent section (1) comprises a plurality of auxetic assemblies (101) which are sequentially connected along the circumferential direction, each auxetic assembly (101) is provided with an anchoring hook (103), and the anchoring hooks (103) are embedded into the wall of a blood vessel for positioning a filter;

when the auxetic component (101) is pulled, the auxetic component expands outwards and drives the anchoring hook (103) to expand outwards.

2. The degradable vena cava filter with auxetic structure according to claim 1, wherein each auxetic assembly (101) is formed by an arrangement of several auxetic cells (1011), the anchoring hooks (103) being fixed on the auxetic cells (1011).

3. The degradable vena cava filter with auxetic structure according to claim 1, further comprising a filter segment (2);

the filter screen section (2) comprises a restraining ring (202) and a filter screen (201), the outer diameter of the restraining ring (202) is smaller than the diameter of the bracket section (1), and the filter screen (201) is arranged between the bracket section (1) and the restraining ring (202);

the filter screen (201) is formed by mutually interweaving a plurality of filter wires (2011), and each filter wire (2011) is respectively connected with the bracket section (1) and the restraint ring (202).

4. The degradable vena cava filter with an auxetic structure according to claim 3, wherein a limiting ring (104) is disposed at one end of each auxetic assembly (101) close to the constraining ring (202), a plurality of filter wires (2011) correspond to the limiting rings (104) one by one, each filter wire (2011) passes through the corresponding limiting ring (104), and each filter wire (2011) is connected with the stent section (1) through the corresponding limiting ring (104).

5. The degradable vena cava filter with auxetic structure according to claim 3, wherein the stent segment (1) is made of a degradable metal material, the constraining ring (202) and the filter wires (2011) are made of biodegradable polymers, and the thickness of the constraining ring (202) is smaller than the diameter of the filter wires (2011).

6. A degradable vena cava filter with auxetic structure according to claim 3, wherein each anchoring hook (103) is arranged obliquely towards the end close to the filter segment (2) in the direction of the axis of the stent segment (1).

7. The degradable vena cava filter with auxetic structure according to claim 1, wherein the tip of each anchoring hook (103) is in a rounded configuration.

8. The degradable vena cava filter with an auxetic structure according to claim 1, wherein a connecting assembly (102) is arranged between every two adjacent auxetic assemblies (101), and any two adjacent auxetic assemblies (101) are connected through the connecting assembly (102).

9. The degradable vena cava filter with auxetic structure of claim 2, wherein the configuration of the auxetic unit (1011) is a concave auxetic structure.

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