CN105662646A - Filter - Google Patents

Abstract

The invention discloses a filter, which mainly includes a near-end filter net and a distal-end filter net, and the taper of the filter net near the proximal end is smaller than the taper of the filter net near the distal end. Therefore, the radial support force of the filter screen at the proximal end is smaller than the radial support force of the filter screen at the distal end. When the emboli is intercepted by the filter screen at the proximal end, the radial support force of the filter screen at the proximal end increases, reducing the difference between the radial support force of the filter screen at the proximal end and the radial support force of the filter screen at the distal end. The gap between them reduces the possibility of filter skew, improves the efficiency of the filter to filter emboli, and reduces the risk of re-embolism in patients after surgery.

Description

filter

technical field

The invention relates to an implanted medical device, in particular to a filter.

Background technique

Pulmonary embolism (abbreviation: PE) refers to the clinicopathophysiological syndrome in which various emboli in the systemic circulation block the pulmonary artery and its branches and cause pulmonary circulation disturbance. It has the characteristics of high morbidity, acute onset, and high mortality. According to statistics, the mortality rate of untreated pulmonary embolism is 20-30%, and the annual new cases account for about 0.2% of the population. According to the calculation of my country's 1.35 billion population, there are about 2.7 million new patients every year.

All kinds of emboli in the systemic circulation can cause pulmonary embolism. The most common type of emboli is a thrombus. There are many factors for the formation of blood clots, including: trauma or bone fractures, trauma, major surgery, extensive burns, pregnancy, childbirth, prolonged illness in bed, long-distance rides or airplanes, sedentary, prolonged sitting and sitting down. Squat and wait. These thrombi are generally slightly adhered to the tube wall and are easy to fall off. The dislodged free emboli can cause serious diseases such as pulmonary embolism. Filters have been clinically proven to be a safe and effective means of preventing pulmonary embolism, which can reduce the incidence of pulmonary embolism. A filter is implanted in the inferior vena cava to prevent blood clots from the lower extremities from reaching the lungs along the bloodstream, thereby preventing pulmonary embolism.

The existing filter tends to be skewed when the emboli are intercepted by the filter screen at the proximal end. The skewed filter reduces the efficiency of filtering emboli, which increases the risk of re-embolism in patients after surgery.

Contents of the invention

The object of the present invention is to provide a filter for the above-mentioned deficiencies in the prior art. The taper of the filter screen at the proximal end of the filter near the proximal end of the filter is smaller than the taper of the filter screen at the distal end of the filter near the distal end of the filter, and the radial support force of the filter screen at the proximal end is smaller than the radial support force of the filter screen at the distal end. . When the emboli is intercepted by the filter screen at the proximal end, the radial support force of the filter screen at the proximal end increases, reducing the difference between the radial support force of the filter screen at the proximal end and the radial support force of the filter screen at the distal end. The gap between them reduces the possibility of filter skew, improves the efficiency of the filter to filter emboli, and reduces the risk of re-embolism in patients after surgery.

The present invention provides a filter comprising a main body having opposite proximal and distal ends. The main body includes a proximal end filter and a distal end filter located between the proximal end and the distal end and connected to each other. When the filter is released naturally, both the filter screen at the proximal end and the filter screen at the distal end are spatially tapered structures formed by a plurality of wires. The taper of the filter net at the proximal end is smaller than the taper of the filter net at the distal end.

In one of the embodiments, the filter at the proximal end comprises a plurality of connected first Y-shaped units. Each first Y-shaped unit includes a first network cable and two second network cables formed by branching from one end of the first network cable. The plurality of first network cables of the plurality of first Y-shaped units converge at the proximal end. The end of the second mesh cable of each of the first Y-shaped units away from the proximal end is connected to the filter at the distal end.

In one of the embodiments, in the state where the filter is naturally released, the distance between the connection point of the first mesh wire and the second mesh wire in any of the first Y-shaped units to the longitudinal central axis of the filter The ratio to the dimension of the largest outer diameter of the filter in a direction perpendicular to the longitudinal central axis of the filter ranges from 1:10 to 7:16.

In one of the embodiments, the two first network lines of every two adjacent first Y-shaped units and the adjacent two second network lines of the corresponding two first Y-shaped units enclose A first diamond-shaped filter unit is formed. In the state where the filter is naturally released, the projected area of the plurality of first diamond-shaped filter units of the filter on a cross-section perpendicular to the longitudinal center axis of the filter is the same as that of the filter in the longitudinal direction perpendicular to the filter The area ratio of the circle corresponding to the maximum outer diameter in the direction of the central axis is in the range of 1:10 to 9:10.

In one of the embodiments, the filter at the distal end includes a plurality of connected second Y-shaped units. Each second Y-shaped unit includes a third network cable and two fourth network cables formed by branching from one end of the third network cable. The multiple third network cables of the multiple second Y-shaped units converge at the distal end. The end of the fourth mesh cable of each second Y-shaped unit away from the distal end is connected to the filter at the proximal end.

In one of the embodiments, in the state where the filter is naturally released, the distance between the connection point of the third mesh wire and the fourth mesh wire in any of the second Y-shaped units to the longitudinal central axis of the filter The ratio of the size of the largest outer diameter of the filter in the direction perpendicular to the longitudinal central axis of the filter after the filter is naturally released is in the range of 1:10 to 7:16.

In one of the embodiments, the filter at the distal end includes a plurality of straight fifth mesh wires. Ends of the plurality of fifth network cables close to the distal end converge at the distal end. The end of each fifth network cable away from the distal end is connected to the supporting section.

In one of the embodiments, the main body further includes a support section connected between the filter at the proximal end and the filter at the distal end. The support section includes a plurality of straight rods. The straight bar is generally parallel to the longitudinal center axis of the filter.

In one of the embodiments, there are multiple straight rods, and the lengths of the multiple straight rods are the same.

In one of the embodiments, the width of the straight bar along the circumferential direction of the filter is greater than that of any mesh line of the filter net at the proximal end and the filter net at the distal end along the circumferential direction of the filter. width.

In one of the embodiments, the support section further includes at least one curved rod. One end of the curved rod is connected with the filter screen at the proximal end, and the other end is connected with the filter screen at the distal end.

In one of the embodiments, the straight rods and the curved rods are distributed in the circumferential direction of the filter at intervals.

In one embodiment, the straight rods and the curved rods are distributed in the circumferential direction of the filter without intervals.

In one of the embodiments, at least one fixing anchor for fixing the filter is provided on at least one of the straight rods. One end of the fixed anchor is fixed on the straight rod, and the other end of the fixed anchor is a free end extending toward the proximal end.

In one embodiment, the included angle between the fixed anchor and the straight rod directly connected thereto is less than 90 degrees.

In one embodiment, the vertical distance from the free end of the fixed anchor to the straight rod directly connected to the fixed anchor is less than or equal to 3 millimeters.

In one of the embodiments, the filter further includes a recovery hook. The recovery hook is arranged at the distal end or the proximal end of the main body. The recovery hook is a tubular structure with an opening. The opening direction of the recovery hook extends outward along the radial direction of the filter and is offset toward the main body. The width of the opening of the recovery hook in a direction perpendicular to the opening is greater than or equal to 1/5 of the outer diameter of the tubular structure of the recovery hook. The depth of the opening of the recovery hook in a direction perpendicular to the longitudinal central axis of the filter is less than or equal to 19/20 of the outer diameter of the tubular structure of the recovery hook.

In one embodiment, the material of the filter is nickel-titanium alloy. The filter is formed by cutting the wires of the near-end filter net and the distal-end filter net on a nickel-titanium tube, and shaping them.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, the taper of the filter screen at the proximal end close to the proximal end of the filter is smaller than the taper of the filter screen at the distal end near the distal end of the filter, and the radial support force of the filter screen at the proximal end is smaller than that of the filter screen at the distal end. When the emboli is intercepted by the filter screen at the proximal end, the radial support force of the filter screen at the proximal end increases, reducing the difference between the radial support force of the filter screen at the proximal end and the radial support force of the filter screen at the far end. The gap between them reduces the possibility of filter skew, improves the efficiency of the filter to filter emboli, and reduces the risk of re-embolism in patients after surgery.

Description of drawings

Figures 1a-1b are schematic diagrams of the overall structure of the filter according to the first embodiment of the present invention. The main body of the filter includes a filter screen at the proximal end, a filter screen at the distal end, and a filter screen connecting the proximal end and the distal end. The support section of the filter, the filter at the proximal end includes a plurality of first diamond-shaped filter units; wherein, Figure 1a is a perspective view, and Figure 1b is a main view;

Figure 1c is a cross-sectional view of the filter described in Figure 1a on a section with a longitudinal central axis of the filter;

Figure 1d is a partial structural front view of the main body of the filter described in Figure 1a;

Fig. 1 e is a projection view of the proximal end filter screen of the filter described in Fig. 1 a on a cross section perpendicular to the longitudinal central axis of the filter;

Fig. 1f is the projected area of a plurality of first diamond-shaped filter units of the filter in Fig. 1a on a cross section perpendicular to the longitudinal central axis of the filter and the filter in the direction perpendicular to the longitudinal central axis of the filter Schematic diagram of the ratio of the area of the circle corresponding to the outer diameter of ;

Fig. 1 g is the projected view of the far-end filter screen of the filter described in Fig. 1 a on the cross-section perpendicular to the longitudinal central axis of the filter;

Fig. 2 is the schematic structural view of the recovery hook of the filter in Fig. 1a;

Fig. 3 is the structural representation of the fixed anchor of the filter in Fig. 1a;

Fig. 4 is a schematic diagram of the filter in Fig. 1a rotating around a fixed anchor;

5a-5b are schematic diagrams of the overall structure of the filter according to the second embodiment of the present invention. The main body of the filter includes a filter screen at the proximal end, a filter screen at the distal end, and a filter screen connecting the proximal end filter screen and the distal end. The supporting section of the filter screen; wherein, Fig. 5a is a perspective view, and Fig. 5b is a main view;

Fig. 5c is a partial structural front view of the main body of the filter described in Fig. 5a;

Figure 5d is a projection view of the filter screen at the distal end of the filter described in Figure 5a on a cross-section perpendicular to the longitudinal central axis of the filter;

FIG. 6 is a developed image of the inferior vena cava after the filter of Comparative Example 1 was implanted in the inferior vena cava 14 days later.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the specification are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

For clarity of description, the end of the filter near the heart and blood flowing out of the filter is called the proximal end, and the end of the filter away from the heart and blood flowing into the filter is called the distal end.

The technical solutions of the present invention will be further described in detail below in conjunction with specific examples.

Embodiment one

In this embodiment, the main body of the filter is cut and shaped from a nickel-titanium tube with an outer diameter of 0.2-4 mm. It can be understood that the filter can also be braided and shaped by nickel-titanium wire with an outer diameter of 0.05-0.8 mm or a nickel-titanium flat belt with a width of 0.05-0.5 mm and a length of 0.15-1 mm. The filter has superelastic and self-expanding properties.

Referring to FIG. 1 a and FIG. 1 b , the filter 100 of the first embodiment includes a main body 10 , a recovery hook 20 and a fixing anchor 30 disposed at one end of the main body 10 .

The main body 10 has a proximal end 101 and a distal end 102, which include a proximal filter 11 near the proximal end 101, a distal filter 12 near the far end 102, and a filter connected to the proximal end. The support section 13 between the net 11 and the filter net 12 at the distal end. After the filter 100 is naturally released in the blood vessel, the supporting section 13 is used to support the blood vessel wall, and the proximal filter 11 and the distal filter 12 are used to filter thrombus. The filter screen 11 at the proximal end is composed of a plurality of mesh wires converged at the proximal end 101 to form a spatial tapered structure. The filter screen 12 at the distal end is composed of a plurality of mesh wires converged at the distal end 102 to form a spatial tapered structure.

Each network line can be straight, or curved, or partly straight and the rest curved.

It can be understood that the mesh wires of the filter screen 11 at the proximal end and the screen wires of the filter screen 12 at the distal end can also be irregular curves or a combination of curves and straight lines.

Referring to Fig. 1c, the taper of the filter screen 11 at the proximal end is that when the filter 100 is in a natural release state, the outer diameter of the distal end of the filter screen 11 at the proximal end is the same as that of the filter screen 11 at the proximal end with the longitudinal central axis of the filter 100 The ratio of the maximum length L1 of the projection on the section along the longitudinal central axis of the filter 100; the taper of the filter screen 12 at the far-center end is when the filter screen 100 is in a natural release state, the outer diameter of the proximal end of the filter screen 12 at the far-center end and the outer diameter of the proximal end of the filter screen 12 The ratio of the maximum length L2 of the projection of the filter screen 12 at the far-center end on the section having the longitudinal central axis of the filter 100 along the longitudinal central axis of the filter 100, and the taper of the filter screen 11 at the proximal end is less than that of the filter screen 12 at the far-center end taper. Preferably, in this embodiment, the outer diameter of the distal end of the proximal filter 11 is equal to the outer diameter of the proximal end of the distal filter 12, and is equal to the longitudinal central axis of the filter 100 perpendicular to the filter 100. The dimension H in the direction of the largest outer diameter.

When the filter 100 is released naturally, the projection of the filter screen 11 at the proximal end on the section with the longitudinal central axis of the filter 100 along the longitudinal central axis of the filter 100 is greater than the maximum length L1 of the filter screen 12 at the distal end in the longitudinal direction with the filter 100 The projection on the section of the central axis is along the maximum length L2 of the longitudinal central axis of the filter 100 .

The proximal end filter 11 near the proximal end 101 has a longer length, which can buffer the blood flow from the distal end 102 into the main body 10 at high speed, so that thrombus can enter the proximal filter 11 in an orderly manner. Therefore, the vortex will not be formed to cause a large impact force on the filter screen 11 at the proximal end and cause the filter 100 to be displaced. Simultaneously, the longer filter screen 11 at the proximal end can ensure that the return blood flow of the two renal veins produces a sufficiently large area and a long enough washing and cutting effect on the thrombus staying in the filter screen 11 at the proximal end, ensuring the long-term maintenance of the vena cava. unobstructed.

Please refer to Fig. 1d and 1e at the same time, the filter screen 11 at the proximal end includes a plurality of connected first Y-shaped units 110, and each first Y-shaped unit 110 includes a first mesh wire 111 and is formed by extending from one end of the first mesh wire. The two second network cables 112. The plurality of first mesh wires 111 of the plurality of first Y-shaped units 110 converge at the proximal end 101 , so that when the filter 100 is naturally released, the proximal end filter mesh 11 has a spatially tapered structure. The end of the second network cable of each first Y-shaped unit 110 away from the proximal end 101 is connected to the supporting section 13 .

The distance from the projection point of the intersection point A of the second mesh line 112 of each first Y-shaped unit 110 and the first mesh line 111 on the longitudinal center axis of the filter 100 to the proximal end 101 and the corresponding second mesh line 112 and the supporting section 13 The ratio of the distance from the projection point of the intersection point on the longitudinal central axis of the filter 100 to the proximal end 101 is in the range of 1:10 to 9:10. Specifically, in this embodiment, the ratio is 1:2.

Each of the first network cable 111 and the second network cable 112 can be straight or curved, or part of it can be curved and the rest can be straight. In this embodiment, the proximal filter 11 includes six straight first mesh wires 111 of equal length and twelve straight second mesh wires 112 of equal length. The included angles formed by every two adjacent first mesh wires 111 at the proximal end 101 are equal.

Please continue to refer to Fig. 1c, when the filter 100 is released naturally, the distance h ₁ from the connection point A of the first mesh wire 111 and the second mesh wire 112 in the first Y-shaped unit 110 to the longitudinal central axis of the filter 100 is perpendicular to the filter 100 The ratio of the dimension H at the largest outer diameter in the direction of the longitudinal central axis of the filter 100 ranges from 1:10 to 7:16. Specifically, in this embodiment, the ratio is 1:4.

Please refer to Fig. 1e and Fig. 1f at the same time, the two first network lines 111 of every two adjacent first Y-shaped units 110 and the adjacent two second network lines 112 of the corresponding two first Y-shaped units 110 surround A first diamond-shaped filter unit 113 is formed. Under the state that described filter is released naturally, the projected area S1 of a plurality of first rhombic filtering units 113 of the near-center end filter screen 11 on the cross section perpendicular to the longitudinal central axis of the filter 100 is different from the longitudinal central axis direction of the filter 100 The ratio of the area S0 of the circle corresponding to the maximum outer diameter on the above ranges from 1:10 to 9:10. Specifically, in this embodiment, the ratio is 5.5:10.

Because the size of the first rhombic filter unit 113 is moderate, it can fully filter the thrombus that will cause pulmonary embolism, and there is no situation that blood vessels are blocked due to the interception of large and small thrombus, which ensures the long-term patency of the vein.

Please refer to FIG. 1d and FIG. 1g at the same time, the distal filter 12 includes a plurality of connected second Y-shaped units 120 . Each second Y-shaped unit 120 includes a third network cable 121 and two fourth network cables 122 formed by branching from one end of the third network cable. The multiple third network cables 121 of the multiple second Y-shaped units 120 converge at the distal end 102 . Therefore, when the filter 100 is naturally released, the filter screen 12 at the distal end has a spatially tapered structure. The end of the fourth network cable 122 of each second Y-shaped unit 120 away from the distal end 102 is connected to the supporting section 13 .

Each of the third network cable 121 and the fourth network cable 122 can be straight or curved, or part of it can be curved and the rest can be straight. In this embodiment, the filter screen 12 at the distal end includes six straight third mesh wires 121 of equal length and six straight fourth mesh wires 122 of equal length. The included angles formed by every two adjacent third mesh wires 121 at the distal end 102 are equal.

Please continue to refer to Fig. 1 c, when the filter 100 is released naturally, the distance h 2 from the connection point B of the third mesh wire 121 and the fourth mesh wire 122 in each second Y-shaped unit 120 to the longitudinal central axis of the filter 100 is equal to the distance h ₂ of the filter 100 The ratio of the dimension H at the largest outer diameter in the direction perpendicular to the longitudinal central axis of the filter 100 ranges from 1:10 to 7:16. Specifically, in this embodiment, the ratio is 1:8.

As can be seen above, the main body 10 of the filter 100 has an asymmetric structure as a whole, and the number of the first Y-shaped units 110 in the filter screen 11 at the proximal end is the number of the second Y-shaped units 120 in the filter screen 12 at the far-center end Twice of that, that is, the density of the mesh structure of the filter screen 11 at the proximal end is greater than the density of the mesh structure of the filter screen 12 at the distal end.

Please refer to FIG. 1a and FIG. 1b again, the support section 13 includes six straight rods 131 with equal lengths. Each straight rod 131 is substantially parallel to the longitudinal central axis of the filter 100 and is evenly spaced along the circumferential direction of the filter 100 .

It can be understood that the straight rod 131 can be directly connected with the filter screen 11 at the proximal end and the filter screen 12 at the distal end, and the straight rod 131 can also pass through a curved section between the filter screen 11 at the proximal end and the filter screen 12 at the distal end. connected.

The width of each straight rod 131 along the circumferential direction of the filter 100 is greater than the width of any wire of the filter screen 11 at the proximal end and the filter screen 12 at the distal end along the circumferential direction of the filter 100 .

In this embodiment, the width of each straight rod 131 along the circumferential direction of the filter 100 is 0.8 mm, and the width of the mesh wire along the circumferential direction of the filter 100 is 0.4 mm.

It can be understood that, in other embodiments, one or more of the straight rods 131 can be replaced by curved rods, as long as the taper of the filter screen at the proximal end of the filter is smaller than the taper of the filter screen at the distal end. . It can also be understood that, in other embodiments, at least one of the plurality of straight rods 131 can be connected to the filter screen at the proximal end or the filter screen at the distal end through at least one curved rod, as long as the proximal end of the filter The taper of the filter screen at the end is less than the taper of the filter screen at the far-center end. It can also be understood that, in other embodiments, one of the plurality of straight rods 131 can also be omitted. At this time, a network wire of the filter screen at the proximal end is directly connected to a network wire of the filter screen at the far-center end. Connected, as long as the taper of the filter screen at the proximal end of the filter is smaller than the taper of the filter screen at the distal end.

It can be understood that, in other embodiments, a plurality of straight rods 131 and curved rods may be distributed at intervals in the circumferential direction of the filter. It can also be understood that, in other embodiments, the straight rods 131 and the curved rods can also be distributed in the circumferential direction of the filter without intervals, for example, all the straight rods 131 can be sequentially distributed in the circumferential direction of the filter, and all the curved rods can follow the straight The rods 131 are sequentially distributed in the circumferential direction of the filter, that is, the curved rods can be randomly arranged among a plurality of straight rods 131 .

It should also be understood that the configuration of the curvilinear rod may include one or more curved wavy wires. Please refer to Fig. 2, in the present embodiment, the recovery hook 20 is arranged at the distal end 102 of the main body 10, and the filter 100 implanted in the blood vessel can be removed from the blood vessel by the connection between the recovery hook 20 and the catcher (not shown). recovered in vitro. The recovery hook 20 is a tubular structure with an opening. The opening direction of the recovery hook 20 extends outward along the radial direction of the filter 100 and deviates toward the main body 10 , that is, the angle β between the opening direction of the recovery hook 20 and the longitudinal central axis of the filter 100 is less than 90 degrees. The width D of the opening of the recovery hook 20 in the direction perpendicular to the opening is greater than or equal to 1/5 of the outer diameter d of the tubular structure of the recovery hook 20 , so that the recovery device can easily catch the recovery hook 20 . The depth S of the opening of the recovery hook 20 in the direction perpendicular to the longitudinal central axis of the filter 100 is less than or equal to 19/20 of the outer diameter d of the tubular structure of the recovery hook 20, so that when the recovery device catches the recovery hook 20, the recovery device The retrieval hook 20 can be pulled into the retrieval sheath. In this embodiment, the width D of the opening of the recovery hook 20 in the direction perpendicular to the opening is 1 mm, and the depth S of the opening of the recovery hook 20 in the direction perpendicular to the longitudinal central axis of the filter 100 is 1.5 mm.

When the filter 100 of this embodiment is scoured by high-speed blood flow in the blood vessel, the filter 100 may tilt. But because the taper of the far-end filter screen 12 near the far-center end 102 is greater than the taper of the proximal-end filter screen 11 near the proximal end 101, the proximal end 101 will contact the blood vessel wall first when the filter 100 is skewed, avoiding The recovery hook 20 located at the distal end 102 cannot grasp the risk of recovery due to contact with the vessel wall. In addition, when the filter 100 of this embodiment is implanted into the human body, the filter 100 in a radially contracted state is released from the sheath, and the radial support force of the proximal filter 11 that is released first is slightly smaller, so the release speed is slow , when it is found that the release position is not good, the partially released proximal filter 11 can be retracted into the sheath, and released again after adjusting the position of the sheath, and the slowly released proximal filter 11 will also stick to the blood vessel wall, ensuring Stability of filter 100 after implantation.

Please refer to FIG. 3 , in this embodiment, the filter 100 further includes a fixing anchor 30 . The fixing anchor 30 is arranged on at least one straight rod 131 of the supporting section 13, and the included angle α between the straight rod 131 directly connected with it is smaller than 90 degrees. The fixing anchor 30 is in the shape of a strip, one end of which is fixed on the straight rod 131 , and the other end is a free end extending toward the proximal end 101 . The vertical distance from the free end of the fixed anchor 30 to the straight rod 131 directly connected with the fixed anchor 30 is less than or equal to 3 millimeters. Thus, when the filter 100 is naturally released in the blood vessel, the straight rod 131 of the support section 13 supports the blood vessel wall, and the anchor 30 penetrates into the blood vessel wall to further provide reliable fixation for the filter 100 and prevent the filter 100 from migrating in the blood vessel. bit. It can be understood that two or more fixed anchors 30 can be arranged on one straight rod 131 according to actual needs. It can be understood that when there is a curved rod inside the support section 13, the anchor 30 can also be arranged on the curved rod according to actual needs.

Please refer to FIG. 4 , when the filter 100 of this embodiment is scoured by high-speed blood flow in the blood vessel, the filter 100 may tilt. But because the taper of the far-end filter screen 12 near the far-center end 102 is greater than the taper of the near-heart end filter screen 11 near the proximal end 101, the radial support force of the far-center end filter screen 12 is larger, which is beneficial to the fixed anchor 30 away from the far-end filter screen. The free end of the heart tip 102 penetrates the vessel wall. When the filter 100 is washed by the blood flow, the filter 100 will only rotate around the fixed anchor 30 at a small angle without displacement, which ensures the stability of the filter 100 after implantation.

The filter 100 is implanted into the inferior vena cava by percutaneously puncturing the femoral vein with a delivery sheath, and it is detected by X-ray imaging equipment that the filter 100 does not tilt, shift or turn over after being implanted in the inferior vena cava. The filter 100 was taken out 14 days after implantation, and the patient did not experience abdominal pain and other discomfort symptoms, that is, the filter 100 did not cause damage to the inner wall of the blood vessel when it was taken out.

Embodiment two

Referring to FIG. 5 a , the structure of the filter 200 of this embodiment is substantially the same as that of the filter 100 of the first embodiment. The filter 200 includes a main body 40 , a recovery hook 50 and a fixing anchor 60 disposed at one end of the main body 40 . The main body 40 has a proximal end 401 and a distal end 402 opposite, which include a proximal filter 41 near the proximal end 401, a distal filter 42 near the far end 402, and a filter connected to the proximal end. The support section 43 between the net 41 and the filter net 42 at the distal end. The difference between the filter 200 and the filter 100 is that the structure of the filter 42 at the distal end is different from the structure of the filter 12 at the distal end.

Please refer to Fig. 5b, Fig. 5c and Fig. 5d at the same time, the difference between the far-end filter net 42 of the present embodiment and the far-central end filter net 42 of the first embodiment is that the far-central end filter net 42 comprises six linear The fifth network cable 421 , the ends of the six fifth network cables 421 near the distal end 402 converge at the distal end 402 . Therefore, when the filter 200 is released naturally, the filter screen 42 at the distal end has a spatially tapered structure. The included angles formed by each of the fifth mesh wires 421 at the distal end 402 are equal. The end of each fifth mesh wire 421 away from the distal end 402 is connected to the filter screen 41 at the proximal end.

Each of the fifth network cables 421 can be straight or curved, or partially curved and the rest are straight.

The filter 200 is implanted into the inferior vena cava by percutaneously puncturing the femoral vein with a delivery sheath, and it is detected by X-ray imaging equipment that the filter 200 does not tilt, shift or turn over after being implanted in the inferior vena cava. The filter 200 was taken out 14 days after implantation, and the patient did not experience discomfort such as abdominal pain, that is, the filter 200 did not cause damage to the inner wall of the blood vessel when it was taken out.

It can be understood that when the filter of the present invention is prepared by cutting and shaping a nickel-titanium tube with an outer diameter of d, it is possible to cut and form a plurality of filter screens at the proximal end and the filter screen at the distal end on the same nickel-titanium tube. Straight rods for network cables and support segments. The width of each straight rod along the circumferential direction of the filter is less than 1/2 of the outer diameter d of the nickel-titanium tube, and the width of the straight rod along the circumferential direction of the filter is greater than that of the proximal filter and the distal filter. The width of the curved segment and/or straight segment of the mesh wire along the circumferential direction of the filter.

When the filter is cut and shaped from a nickel-titanium tube with an outer diameter of d, the recovery hook can be integrally formed with the main body of the filter, that is, the recovery hook can be formed by directly cutting an opening at the end of the nickel-titanium tube. When the filter adopts nickel-titanium wire or nickel-titanium flat belt by weaving and shaping, the recovery hook can also be a nickel-titanium tube with an opening and an outer diameter of d, which can be connected to the proximal end or the main body of the filter. The distal end is connected as a whole by welding.

It should also be understood that the recovery hook can also be arranged at the proximal end of the main body according to actual needs, as long as the delivery device for delivering the filter can place the filter at a predetermined position in the blood vessel, and the recovery device for recovering the filter can be connected to the recovery hook, and Retrieve the filter and exit the blood vessel.

It can be understood that the filter of the present invention can also be made of other superelastic materials (for example, stainless steel wire, cobalt-chromium-nickel-molybdenum-iron alloy, cobalt-chromium alloy or polymer), and can also be made of self-expanding Any other suitable material.

In summary, after the filter of the present invention is implanted into a human blood vessel and released naturally in the blood vessel, the taper of the filter screen at the proximal end near the proximal end of the filter is smaller than that of the filter screen at the distal end near the distal end of the filter. The radial support force of the filter screen at the central end is smaller than the radial support force of the filter screen at the distal end. Compared with the prior art, the advantages of the filter of the present invention are: 1) When the emboli are intercepted in the filter screen at the proximal end, the radial support force of the filter screen at the proximal end increases, reducing the size of the filter screen at the proximal end. The gap between the radial support force of the radial support force and the radial support force of the filter at the distal end reduces the possibility of filter skew, improves the efficiency of the filter for filtering emboli, and reduces the risk of re-embolization of patients after surgery; 2 ) When the filter with the recovery hook set at the distal end is implanted into the human body, the filter in the radially contracted state is released from the sheath, and the radial support force of the filter screen at the proximal end that is released first is slightly smaller, so the release speed Slowly, when it is found that the release position is not good, you can retract the partially released filter at the proximal end of the sheath, adjust the position of the sheath and release it again, and the filter at the proximal end that is slowly released will also stick to the blood vessel wall, ensuring that the filter Stability after implantation; 3) The radial support force of the filter at the distal end is slightly larger. The strength of the blood vessel is greater, which ensures the stability of the filter after implantation; 4) The length of the filter screen at the proximal end is greater than the length of the filter screen at the distal end, so that multiple thrombus can enter the filter screen at the proximal end in an orderly manner, avoiding multiple A thrombus causes eddy currents at the inlet of the filter screen at the proximal end, which avoids the impact of the vortex on the filter body and reduces the possibility of filter skew; 5) The filter screen at the proximal end includes multiple Moderately sized diamond-shaped filter unit, multiple moderately sized diamond-shaped filter units can not only fully filter thrombus, but also avoid the occurrence of blood vessel blockage due to the interception of large and small thrombus, ensuring long-term patency of veins.

Comparative example one

The structure of the filter of Comparative Example 1 is substantially the same as that of the filter 100 of Embodiment 1, which includes a proximal filter near the proximal end, a distal filter near the far end, and a filter connected to the proximal filter and the distal end. Support segment between end filters. The difference is that, after the filter of Comparative Example 1 is naturally released in the blood vessel, the taper of the filter screen at the proximal end is greater than that of the filter screen at the distal end.

The filter of Comparative Example 1 was implanted into the inferior vena cava by percutaneously puncturing the femoral vein with a delivery sheath. Since the taper of the filter screen at the proximal end is greater than the taper of the filter screen at the distal end, the radial support force of the filter screen at the proximal end is greater than the radial support force of the filter screen at the distal end. However, after implantation, the filter at the proximal end intercepts the emboli in the blood, and this gap gradually increases, eventually causing the filter to be skewed, which affects the filtration efficiency of the filter; and, due to the skew of the filter, part of the fixed anchor is lost. The contact position between the free end and the vessel wall is unstable. During breathing, due to changes in abdominal pressure, the anchor penetrates and pulls out of the vessel wall many times, causing the vessel to be punctured at this position, and the patient suffers from abdominal pain and other discomfort. After detection by imaging equipment, the patient developed abdominal hematoma, and the filter was removed in advance, which did not achieve the expected therapeutic effect.

Please refer to FIG. 6 , as detected by the imaging device, at the implantation position of the inferior vena cava before the filter is taken out, the blood vessel wall of the inferior vena cava is punctured and blood flows out to form a hematoma. It can be seen that the filter of this comparative example caused damage to blood vessels after implantation.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are only illustrative, rather than restrictive, and those of ordinary skill in the art will Under the enlightenment of the present invention, many forms can also be made without departing from the gist of the present invention and the protection scope of the claims, and these all belong to the protection of the present invention.

Claims (18)

1. A kind of filter, described filter comprises the main body portion that has opposite near-center end and far-center end, and described main body portion comprises and is positioned at between described near-center end and far-center end and is connected near-center end filter net and far-end The filter screen at the heart end, in the state where the filter is naturally released, the filter screen at the proximal end and the filter screen at the distal end are both spatially tapered structures formed by a plurality of wires, and it is characterized in that the filter screen at the proximal end The taper of the mesh is smaller than the taper of the filter mesh at the distal end. 2. The filter according to claim 1, wherein the proximal end filter pack comprises a plurality of connected first Y-shaped units, each first Y-shaped unit comprises a first network cable and is connected by the first Y-shaped unit. Two second network cables formed by bifurcating at one end of a network cable, the plurality of first network cables of the plurality of first Y-shaped units converge at the proximal end, and each of the first Y-shaped units The ends of the second network cable away from the proximal end are all connected to the filter screen at the distal end. 3. The filter according to claim 2, characterized in that, in the state of the natural release of the filter, the connecting point of the first network cable and the second network cable in any one of the first Y-shaped units is connected to the connection point of the second network cable. The ratio of the distance from the longitudinal central axis of the filter to the dimension of the largest outer diameter of the filter in a direction perpendicular to the longitudinal central axis of the filter ranges from 1:10 to 7:16. 4. The filter according to claim 2, characterized in that, the two first network cables of every two adjacent first Y-shaped units and the corresponding two adjacent first Y-shaped units Enclosed by two second mesh wires, a first rhombic filter unit is formed. In the state where the filter is naturally released, a plurality of the first rhombic filter units of the filter are perpendicular to the longitudinal central axis of the filter The ratio of the projected area on the cross-section of the filter to the area of the circle corresponding to the maximum outer diameter of the filter in the direction perpendicular to the longitudinal central axis of the filter is in the range of 1:10 to 9:10. 5. The filter according to claim 1, wherein the filter at the distal end comprises a plurality of connected second Y-shaped units, and each second Y-shaped unit comprises a third network cable and is connected by the first Y-shaped unit. The two fourth network cables formed by bifurcating at one end of the three network cables, the multiple third network cables of the multiple second Y-shaped units converge at the distal end, and the first network cables of each second Y-shaped unit The ends of the quadruple wires away from the distal end are all connected to the filter screen at the proximal end. 6. The filter according to claim 5, characterized in that, in the state where the filter is naturally released, the connection point between the third network cable and the fourth network cable in any of the second Y-shaped units is connected to the The ratio of the distance from the longitudinal central axis of the filter to the dimension of the largest outer diameter of the filter in the direction perpendicular to the longitudinal central axis of the filter after the filter is naturally released is in the range of 1:10 to 7:16. 7. The filter according to claim 1, wherein the filter screen at the distal end comprises a plurality of linear fifth mesh wires, and the ends of the plurality of fifth mesh wires near the distal end are at the converge at the distal end, and the end of each of the fifth mesh wires away from the distal end is connected to the filter at the proximal end. 8. The filter according to claim 1, wherein the main body further includes a support section connected between the filter screen at the proximal end and the filter screen at the distal end, and the support section includes a plurality of straight rod, the straight rod is generally parallel to the longitudinal central axis of the filter. 9 . The filter according to claim 8 , wherein there are multiple straight rods, and the lengths of the multiple straight rods are the same. 10. The filter according to claim 8, characterized in that, the width of the straight bar along the circumferential direction of the filter is greater than that of any mesh line of the filter screen at the proximal end and the filter screen at the distal end. The width of the filter in the circumferential direction. 11. The filter according to claim 8, characterized in that, the support section further comprises at least one curved rod, one end of the curved rod is connected with the filter net at the proximal end, and the other end is connected with the filter net at the proximal end. The remote end filter is connected. 12 . The filter according to claim 11 , wherein the straight rods and the curved rods are spaced apart in the circumferential direction of the filter. 13 . 13 . The filter according to claim 11 , wherein the straight rods and the curved rods are not spaced and distributed in the circumferential direction of the filter. 14 . 14. The filter according to claim 8, wherein at least one of the straight rods is provided with at least one fixed anchor for fixing the filter, and one end of the fixed anchor is fixed on the straight rod , the other end of the fixed anchor is a free end and extends toward the direction of the proximal end. 15. The filter according to claim 14, wherein the angle between the fixed anchor and the straight rod directly connected thereto is less than 90 degrees. 16 . The filter according to claim 14 , wherein the vertical distance from the free end of the fixed anchor to the straight rod directly connected to the fixed anchor is less than or equal to 3 millimeters. 17. The filter according to claim 1, characterized in that, the filter further comprises a recovery hook, the recovery hook is arranged at the distal end or the proximal end of the main body; the recovery hook has an opening The tubular structure, the opening direction of the recovery hook extends outward along the radial direction of the filter and is offset towards the main body; the width of the opening of the recovery hook in the direction perpendicular to the opening is greater than or equal to 1/5 of the outer diameter of the tubular structure of the recovery hook, and the depth of the opening of the recovery hook in the direction perpendicular to the longitudinal central axis of the filter is less than or equal to 19% of the outer diameter of the tubular structure of the recovery hook /20. 18. The filter according to claim 1, characterized in that, the material of the filter is a nickel-titanium alloy, and the filter is formed by cutting on a nickel-titanium tube to form the proximal filter screen and the distal filter. The network cable of the net is shaped and formed.