WO2008034315A1

WO2008034315A1 - Double deck venous fileter

Info

Publication number: WO2008034315A1
Application number: PCT/CN2007/001259
Authority: WO
Inventors: Danian Ke; Qingliang Zhou; Qifeng Mei; Xianguo Zhang; Qiyi Luo
Original assignee: Microport Medical (Shanghai) Co., Ltd.
Priority date: 2006-09-14
Filing date: 2007-04-18
Publication date: 2008-03-27
Also published as: CN101143114A; CN101143114B

Abstract

A double-layer deck venous filter includes an upper layer screen and a lower layer screen (1, 2). The upper layer screen (1) is connected to the lower layer screen (2) through a connecting rod (3) disposed in the middle of the screens (1, 2). Each of the upper layer screen (1) and the lower layer screen (2) consists of several filter threads (4, 5) which are led from the center of the screens (1, 2) and are unidirectional and collateral. The shape of the filter threads (4, 5) is chrysanthemumpetal, and the filter threads (4, 5) are radiated from the center of the screens (1, 2) to the peripheral of the screens (1, 2). The filter threads (4) of the upper layer screen (1) are denser than the filter threads (5) of the lower layer screen (2). The filter threads (5) of the lower layer screen (2) are sparse to filter off big thrombus, and the upper layer screen (1) comes into use gridding screen with small density, or the filter threads (4) of the upper layer screen (1) are dense, in order to filter off small thrombus.

Description

Double-layer venous filter

The present invention is in the field of human implantable devices in biomedical materials, and more particularly to a device for filtering and capturing thrombus or other masses in blood vessels, particularly in the vena cava. Background technique

When a blood clot or other vascular wall exfoliation in the human venous blood flow exists, it can enter the pulmonary artery through the heart, causing blockage of the pulmonary artery, resulting in death. The filter traps these thrombi and retains it in the vena cava, followed by thrombolysis or thrombectomy to prevent the above hazards. However, the previous filters used a single layer structure, the design is loose, only the large thrombus can be filtered, and the smaller thrombus can pass. For example, the filter is denser to filter the smaller thrombus, but it may also be because The accumulation of blood clots blocks the venous blood vessels. Summary of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to create a double venous filter that retains a suitable area of blood flow channels to ensure unobstructed blood flow and effective filtration of smaller thrombi to overcome the above-discussed deficiencies of the prior art.

The technical solution of the present invention to solve the technical problem is as follows:

A double-layer venous filter, comprising: a top and bottom two-layer filter screen, wherein the upper and lower two-layer filter nets are connected by a connecting rod disposed at a center of the filter screen, and the upper layer filter screen is a grid-like structure. The lower filter screen is composed of a plurality of unidirectional parallel filter wires which are drawn from the center of the filter screen, and the filter wires are diverged from the center of the filter mesh in a chrysanthemum valve shape, and the distribution density of the upper filter mesh is greater than that of the lower filter. The distribution density of the filter wire of the net.

A double-layer venous filter, comprising: two upper and lower filter screens, the upper and lower layers The screens are connected by a connecting rod disposed at the center of the screen, and the upper screen and the lower screen are each composed of a plurality of unidirectional parallel filter wires drawn from the center of the screen, the filter wires being chrysanthemum petals It is diverged from the center of the screen, and the distribution of the filter of the upper filter is denser than that of the filter of the lower filter.

Further, the filter wire tail portion of the lower filter screen is provided with an upwardly bent hook, the angle between the hook and the central axis of the filter screen is 20 to 100 degrees, and the filter wire is uniformly arranged with the center of the filter mesh as a center. .

Further, the filter wire of the upper filter screen has an arc shape, and the filter wire tail portion is provided with a vertical segment. According to the technical solution disclosed above, the double-layer venous filter of the present invention has a two-layer filter screen, so that the filter screen of the lower filter screen is sparsely distributed, and is used for filtering a large thrombus; and the upper layer adopts a grid with a lower density. The filter screen, or the filter screen of the upper filter screen is densely distributed to filter the smaller thrombus. In addition, the two layers can retain a considerable area of blood flow channels to ensure smooth blood flow. The double-layer venous filter of the invention has the following advantages compared with the previous similar products -

(1) Different double-layer filtering structure makes the filter filter the large thrombus in the lower layer, and the small blood plug remains in the upper layer, thus filtering more thrombus and not blocking the blood vessel.

(2) The double-layer structure of the filter is matched with the vertical section structure of the arc of the "petal" of the dense layer to ensure good central positioning performance when the filter is released, so that the filter will not tilt after being implanted into the blood vessel. '

(3) The hook of the sparse "petal" can make the filter easily break into the blood vessel wall, prevent the filter from being washed away by the blood flow, and the direction of the hook is easy to be extracted, so as to minimize the damage of the blood vessel when the filter is recovered. .

(4) The stepped design on the petal stem of the lower layer of the filter facilitates the pushing of the filter in the conveyor so that the hook does not scratch the vessel wall;

(5) The end hooks of the filter and the overall design make it easy to recycle. DRAWINGS

Figure 1 is a schematic view showing the structure of a double venous filter of the present invention; Fig. 2 is a schematic view showing the working state of the filter of Fig. 1 when it is implanted into a blood vessel. detailed description

The invention will now be further described with reference to the drawings and specific embodiments.

As shown in FIG. 1 and FIG. 2, the double-layer venous filter of the present invention comprises upper and lower two-layer filter screens 1 and 2, and the upper and lower two-layer filter screens 1 and 2 are connected by a connecting rod 3 disposed at the center of the filter screen. The upper screen 1 and the lower screen 2 are each composed of a plurality of unidirectional parallel filter wires 4 and 5 which are led out from the center of the screen, and the filter wires 4 and 5 are chrysanthemum-like and diverged from the center of the sieve to the periphery. The distribution of the filter filaments 4 of the upper filter screen is denser than that of the filter filaments 5 of the lower filter screen. The invention can also adopt the grid structure of the upper layer filter, and the filter screen structure of the lower layer filter screen, so that the distribution density of the upper layer filter grid is larger than the distribution density of the filter screen of the lower layer screen, thereby facilitating the filtration of smaller thrombus.

The filter wires 4 of the upper filter are 7 to 12, and the filter 5 of the lower filter 2 is 4 to 6, and the filter is uniformly distributed at the center of the filter.

The material used in the filter is a NiTi shape memory alloy. With its excellent shape memory effect and superelasticity, the filter released from the delivery catheter can immediately restore its original design shape and function to filter thrombus in the blood vessel. . At the same time, NiTi alloy has good biocompatibility and blood compatibility, which ensures the safety during use. The filter can be prepared by welding the NiTi wire and heat-setting it. The MTi tube can also be laser-cut and heat-treated. Such filters can also be made from other medical elastic alloys, such as CoCr alloys.

The tail portion of the filter 5 of the lower screen is provided with an upwardly bent hook 501, and the angle α of the hook 501 and the central axis of the screen is 20 100 degrees. The lower screen 2 has at least three filter wires 5, and a hook 501 is provided at the tail, and the filter wires with hooks are spaced apart. The hook can cause the filter to hang on the vessel wall to prevent displacement under the impact of blood flow. The lower filter screen has a hooked filter wire which is stepped on the wire body 502 of a section near the hook 501, which facilitates pushing of the filter in the conveyor so that the hook does not scratch the blood vessel wall. The filter wire 4 of the upper filter screen has an arc shape, and the filter wire tail portion is provided with a vertical segment 401.

The invention also includes a hook 6 disposed at the tail of the filter that is disposed at the outer center of the upper screen. Used for recycling.

As shown in the schematic view of the working state of the filter implanted in the blood vessel 7 of Fig. 2, the direction of the arrow in the figure is the direction of blood flow, and the upper filter is placed downstream of the direction of blood flow during use. For clinical use, the filter of the present invention must be used under X-ray contrast monitoring. When in use, it is pressed from the tail into a plastic catheter inserted into the blood vessel. The plastic catheter can be self-developed or the head is marked with an X-ray development mark to indicate the location of the catheter in the blood vessel of the human body. Push the push rod to the head of the catheter, then secure the push rod and withdraw the catheter to release the filter into the defined area of the blood vessel.

Example

The a-shaped filter was fabricated by laser cutting with a NiTi tube. The sparse layer has six legs, the dense layer has twelve legs, and the outer diameter is 034 nrai and the length is 40 mm. In a simulated blood vessel of 028 mm, a physiological saline solution was used for blood flow, and blood tofu was used as a blood clot to perform filtration. The results showed that the sparse end can filter the thrombus with a diameter of more than 5mm, and the dense end can filter the thrombus of 2.5~5mm. The thrombus is stored in the middle, and the blood flow remains smooth after filtering.

Claims

Rights request

A double-layer venous filter, comprising: a top and bottom two-layer filter screen, wherein the upper and lower two-layer filter nets are connected by a connecting rod disposed at a center of the filter screen, wherein the upper layer filter screen is a grid-like structure The lower filter screen is composed of a plurality of unidirectional parallel filter wires drawn from the center of the filter screen, and the filter wires are dilated in a chrysanthemum shape from the center of the filter mesh, and the distribution density of the upper filter mesh is greater than The distribution density of the filter screen of the lower screen.

2. A double-layered venous filter, comprising: a top and bottom two-layer filter screen, wherein the upper and lower two-layer filter nets are connected by a connecting rod disposed at a center of the filter screen, wherein the upper layer filter screen and the lower layer filter screen are both The utility model is composed of a plurality of unidirectional parallel filter wires which are led out from the center of the filter screen, and the filter wires are diverged from the center of the filter mesh in a chrysanthemum valve shape, and the filter wire distribution of the upper filter mesh is smaller than the filter filter distribution of the lower filter mesh. dense.

The double-layer venous filter according to claim 2, wherein the filter screen of the upper filter is 7 to 12, and the filter of the lower filter is 4 to 6, the filter Set the center of the filter as a center.

The double-layered venous filter according to claim 1 or 2, wherein the filter is made of a Nitinol shape memory alloy or a medical CoCr alloy.

The double-layer venous filter according to claim 1 or 2, wherein the filter wire tail portion of the lower filter screen is provided with an upwardly bent hook, and the angle between the hook and the central axis of the screen is 20~100 degrees.

The double-layer venous filter according to claim 3, wherein the lower screen has at least three filter filament tails provided with hooks, and the hook-shaped filter filaments are spaced apart.

The double-layer venous filter according to claim 5, wherein the lower filter screen has a hook-shaped filter filament which has a stepped shape in a portion of the near hook.

The double-layer venous filter according to claim 2, wherein the upper layer filter The filter wire has an arc shape, and the filter wire has a vertical section at the tail.

The double-layer venous filter according to claim 1 or 2, further comprising a hook provided at the tail of the filter, which is disposed at an outer center of the upper screen.