Vein double-layer covered stent

Abstract

The utility model discloses a vein double-layer covered stent which comprises a stent body, the stent body is of a tubular structure with a hollow tube wall, the whole stent body is lined with a double-layer covered film matched with an inner cavity of the stent body, a covered film cavity is formed between the double-layer covered film, and the covered film cavity is a cylindrical sealed cavity. The utility model is used for stent implantation after the patient with the pressed or blocked iliac vein is opened or the balloon is expanded, and conforms to the vein blood flow while keeping the iliac vein unobstructed for a long time, so as to relieve the obstruction of the outflow tract and maintain the unobstructed iliac vein for a long time.

Description

Technical Field

[0001] The utility model relates to a double-layer covered vein stent, belonging to the technical field of medical devices. Background Art

[0002] The main pathophysiological mechanisms of chronic venous insufficiency are venous reflux, obstruction or both occurring simultaneously. Proximal venous obstruction may be the main cause of chronic venous insufficiency. In the past, pressure therapy and venoactive drugs were the basis for the treatment of chronic venous insufficiency. However, in some cases, symptoms can be significantly relieved by stent implantation to recanalize veins or correct obstructive iliac vein lesions, and the mid- and long-term patency rate is high. However, there is currently a lack of dedicated venous stent technology, mainly using the concept of bare stents for lower limb arteries. The bare metal stent is a rigid structure, while the vein is a capacitance vessel. When the rigid stent is placed in the vein lumen, it will straighten the soft vein and change the hemodynamics here. Therefore, clinically, there is a need for a dedicated venous stent that can conform to blood flow. Summary of the Invention

[0003] The technical problem to be solved by the utility model is: for patients with chronic venous insufficiency, how to make the stent conform to blood flow.

[0004] To solve the above technical problem, the technical solution of the utility model is to provide a double-layer covered vein stent, which is characterized in that it includes a stent. The stent is a tubular structure with a hollowed-out tube wall. The whole stent is lined with a double-layer film that matches its inner cavity. A film cavity is formed between the double-layer films, and the film cavity is a cylindrical sealed cavity.

[0005] Preferably, the head end of the stent is a hollowed-out bare stent.

[0006] Preferably, the film cavity is filled with a gas that can be compressed at the position where the film cavity is flowed through by blood as the blood flows.

[0007] Preferably, the film cavity is filled with carbon dioxide gas.

[0008] Preferably, the double-layer film is composed of a first film and a second film. The first film and the second film form a sealed film cavity. The second film is connected to the inner wall of the stent, and the first film is arranged inside the inner circle of the second film.

[0009] Preferably, both the first film and the second film are heparin-coated expanded polytetrafluoroethylene material films.

[0010] Preferably, the stent is a self-expanding, braided, nitinol metal stent.

[0011] This utility model is used for stent implantation after the iliac vein is compressed or occluded and then opened or balloon dilated. While maintaining the long-term patency of the iliac vein, it conforms to the venous blood flow to relieve the outflow tract obstruction and maintain long-term patency.

[0012] Compared with the prior art, this utility model specifically has at least one of the following advantages:

[0013] 1) The self-expanding, braided, nitinol metal stent has both strong radial support force and good flexibility;

[0014] 2) The heparin-coated ePTFE membrane has a certain ability to resist thrombosis;

[0015] 3) The film-covered structure with a carbon dioxide gas cavity can conform to the blood flow, and the lumen decreases or expands correspondingly with the blood flow;

[0016] 4) The bare stent at the head end has good anchoring characteristics and does not block the blood flow on the opposite side;

[0017] 5) The film has a certain effect of isolating thrombus. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a side schematic view of a double-layer film-covered venous stent;

[0019] Figure 2 It is a cross-sectional schematic view of a double-layer film-covered venous stent. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make this utility model more obvious and understandable, preferred embodiments are hereby described in detail in conjunction with the accompanying drawings as follows.

[0021] This utility model provides a double-layer film-covered venous stent, as shown in Figure 1 、 Figure 2 It includes a stent 101. The entire stent 101 is lined with a double-layer film that matches its inner cavity. The double-layer film is composed of a first film 102 and a second film 103. The first film 102 and the second film 103 form a film cavity 104, and the film cavity 104 is filled with carbon dioxide (CO2) gas. The head end of the stent 101 is a hollow bare stent 105 to avoid blocking the blood flow of the opposite iliac vein. The length of the film cavity 104 is almost the same as the length of the stent 101, only differing by the distance of the bare stent 105. Among them, the second film 103 is connected to the inner wall of the stent 101, and the first film 102 is arranged inside the second film 103, so that the film cavity 104 forms a cylindrical sealed cavity.

[0022] In this embodiment, the stent 101 is a self-expanding, braided, nitinol stent, which can ensure sufficient radial support force and balance flexibility. The first membrane 102 and the second membrane 103 are both heparin-coated expanded polytetrafluoroethylene (ePTFE) material membranes.

[0023] The usage method of the present utility model is as follows:

[0024] For patients with iliac vein compression stenosis or occlusion, after the guide wire is opened, balloon dilation is performed. If there is a thrombus, thrombus aspiration is performed first. After the balloon dilation is completed, angiography is performed. According to the diameter of the normal part of the vein at the proximal and distal ends, a product of appropriate size (i.e., the venous double-layer membrane stent of the present utility model) is selected, pre-loaded into a delivery sheath of appropriate size, and the product is introduced into the corresponding iliac vein lesion site along the guide wire through the delivery sheath. Centered on the lesion, it is opened and released through the release device on the end handle of the delivery sheath. The membrane part at the head end of the stent 101 shall not exceed the iliac vein opening site, and angiography is performed again to evaluate the blood flow patency.

[0025] The working process of the present utility model is as follows:

[0026] When blood enters from one end of the stent 101, through the impact of the blood, the volume of the membrane cavity 104 at the impact end shrinks, that is, the first membrane 102 moves closer to the second membrane 103 end. After the blood impact, the first membrane 102 at this position resumes its original state, or due to the forward movement of the blood, that is, the position in front of the membrane cavity 104 is squeezed, and the original membrane cavity 104 may bulge outwards. In this way, the blood gradually moves forward, causing the first membrane 102 to surge in a wavy shape, so that the blood can maintain patency and avoid straightening the soft vein and changing the hemodynamics at this place.

[0027] The specific features of the present utility model are as follows:

[0028] Iliac vein lesions have relatively high requirements for the radial support force of the stent, and iliac vein lesions have certain requirements for the flexibility of the stent. Therefore, the stent 101 of the present utility model is a self-expanding, braided, nitinol stent, which can ensure sufficient radial support force and balance flexibility;

[0029] The iliac vein belongs to a capacitance vessel. Its relaxation and contraction mainly promote blood return, and carbon dioxide gas has certain acceptability and compressibility. The blood flow pressure in the vein is small, and the pressure difference between the proximal and distal ends of the stenotic lesion is not large. Therefore, through the membrane cavity 104 filled with carbon dioxide gas, the membrane cavity 104 can change its shape well with the blood flow.

Claims

1. A double-layer venous covered stent, characterized in that, It includes a stent (101), and the stent (101) is a tubular structure with a hollowed-out tube wall. The entire stent (101) is lined with a double-layered film that matches its inner cavity. A film cavity (104) is formed between the double-layered films, and the film cavity (104) is a cylindrical sealed cavity.

2. The double-layer venous covered stent according to claim 1, wherein The head end of the stent (101) is a hollowed-out bare stent (105).

3. The double-layer venous covered stent according to claim 1, characterized in that, The film cavity (104) is filled with a gas that can be compressed at the position where the film cavity (104) is flowed through by blood as the blood flows.

4. A double-layer covered venous stent according to claim 1 or 3, characterized in that The film cavity (104) is filled with carbon dioxide gas.

5. The double-layer covered stent for vein according to claim 1, characterized in that The double-layered film is composed of a first film (102) and a second film (103). The first film (102) and the second film (103) form a sealed film cavity (104). The second film (103) is connected to the inner wall of the stent (101), and the first film (102) is arranged in the inner circle of the second film (103).

6. The double-layer venous covered stent according to claim 5, wherein Both the first film (102) and the second film (103) are films made of heparin-coated expanded polytetrafluoroethylene material.

7. The double-layered venous covered stent according to claim 1, wherein The stent (101) is a self-expanding, braided, nitinol metal stent.

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