Covered stent

Abstract

The invention discloses a covered stent, and relates to the technical field of interventional medical instruments, the covered stent comprises a stent main body and a covered layer, the diameter of the stent main body is gradually reduced from one end to the other end, and the end, with the larger diameter, of the stent main body is provided with an inclined opening; the film covering layers are fixedly arranged on the inner side and the outer side of the stent main body, the film covering layers are made of woven structures, and a space defined by the film covering layers located on the inner side of the stent main body forms a sub-runner. According to the covered stent, the amount of blood flowing into a branch runner is increased, and the thrombus formation probability is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of interventional medical devices, and particularly to a covered stent. Background Art

[0002] The purpose of the transjugular intrahepatic portosystemic shunt (TIPS) is to establish an artificial channel connecting the portal vein and the hepatic vein in the liver. The TIPS surgery accesses through the jugular vein, punctures the intrahepatic portal vein, and establishes a porto-systemic shunt between the hepatic vein and the portal vein, thereby reducing the portal vein pressure and achieving the purpose of treating portal hypertension complications. However, during the use of the existing shunt channel structure, the pressure at the inlet end is relatively large, resulting in a relatively small blood flow at the inlet of the shunt channel, and thus it is prone to form thrombus due to platelet aggregation. Summary of the Invention

[0003] The purpose of the present invention is to provide a covered stent to solve the problems existing in the above-mentioned prior art, increase the amount of blood flowing into the shunt channel, and reduce the probability of thrombus formation.

[0004] To achieve the above purpose, the present invention provides the following solutions:

[0005] The present invention provides a covered stent, including:

[0006] A stent body, the diameter of which gradually decreases from one end to the other end, and a bevel is provided at the end with a larger diameter of the stent body;

[0007] A covered layer, fixedly arranged on the inner side and the outer side of the stent body, the covered layer is made of a braided structure, and the space surrounded by the covered layer located on the inner side of the stent body forms a shunt channel.

[0008] Preferably, the covered layer includes an inner covered layer and an outer covered layer, and the inner covered layer and the outer covered layer completely wrap the stent body.

[0009] Preferably, the inner covered layer and the outer covered layer are fixedly connected at the end and form a sealed cavity, and the stent body is located in the sealed cavity.

[0010] Preferably, the braided pattern of the covered layer is a wavy structure or a spiral structure.

[0011] Preferably, the covered layer has voids or micropores.

[0012] Preferably, the diameter dimension of the end with a larger diameter of the stent body is 10-12 mm.

[0013] Preferably, the diameter dimension of the end with a smaller diameter of the stent body is 6-8 mm.

[0014] Preferably, a first radiopaque marker is provided at the smaller-diameter end of the stent body. The first radiopaque marker is located outside the membrane layer. The first radiopaque marker is arranged obliquely, and one end thereof points to the inferior vena cava.

[0015] Preferably, a second radiopaque marker is provided at the larger-diameter end of the stent body. The second radiopaque marker is located outside the membrane layer, and the plane where the second radiopaque marker is located is parallel to the plane where the beveled opening is located.

[0016] Preferably, the stent body is a hollow structure or a hinge structure.

[0017] The present invention has achieved the following technical effects compared with the prior art:

[0018] The present invention adopts a variable-diameter design, such that the inflow end of the shunt channel has a large diameter and the outflow end has a small diameter. A beveled opening is provided at the inflow end of the covered stent, further expanding the port cross-sectional area of the inflow end, thereby increasing the blood inflow volume, reasonably adjusting the shunt volume at the outflow end, and reducing the probability of platelet aggregation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of the covered stent of the present invention;

[0021] Figure 2 It is a schematic structural diagram of the stent body of the present invention;

[0022] In the figure: 1 - stent body, 2 - membrane layer, 3 - beveled opening, 4 - first radiopaque marker, 5 - second radiopaque marker. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0024] The purpose of the present invention is to provide a covered stent to solve the problems existing in the above prior art, increase the amount of blood flowing into the shunt channel, and reduce the probability of thrombus formation.

[0025] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] A transjugular intrahepatic portosystemic shunt (TIPS) covered stent is an interventional radiology technique used to treat portal hypertension in cirrhotic patients. TIPS creates a channel connecting the portal venous system and the systemic circulation system within the liver to reduce the pressure in the portal vein, thereby alleviating the related complications caused by portal hypertension. This process is usually performed by an interventional radiologist using catheter techniques guided by X-rays or ultrasound to establish a connection between the portal vein and the hepatic vein. The inventor found that although the portal vein pressure can be reduced after establishing a catheter between the portal vein and the hepatic vein, the blood will not enter the intrahepatic blood vessels, which is not conducive to the recovery of the liver. To solve this problem, the present invention provides a covered stent, as Figure 1 and Figure 2 shown, including a stent body 1 with a diameter gradually decreasing from one end to the other end. A covered layer 2 is fixedly attached to the inner side of the stent body 1, and a covered layer 2 is also fixedly attached to the outer side. The covered layer 2 and the stent body 1 can be connected by bonding, winding, or fitting. The covered layer 2 and the stent body 1 together form a covered stent, and the channel inside the covered stent forms a shunt channel. The end of the covered stent with a smaller diameter is used to communicate with the inferior vena cava; the end with a larger diameter is used to communicate with the portal vein to achieve the effect of reducing the portal vein pressure.

[0027] In one embodiment, to make the shunt channel more complete, the stent body 1 is made of a woven metal layer. The metal layer is a hollow structure with regular or irregular holes. It is formed by helically winding metal wires together. The connection points of adjacent metal wires are hinge-like structures, or the connection points of adjacent two metal wires are connected by overlapping, riveting, or fixed bonding. The structure formed by winding the axially arranged metal wires can be a circular structure, a wavy structure, or a cross-shaped structure. Multiple metal wires are arranged in sequence along the axis to form an overall metal layer. The metal wires forming the metal layer are made of medical memory alloy or other medical compliant metal materials, having a certain support strength and meeting the compliance requirements.

[0028] In this embodiment, the inner and outer sides of the stent body 1 are respectively covered with membranes. The membranes on the inner and outer sides can be independently arranged to achieve full coverage of the stent body 1. Alternatively, the membrane layer 2 on the inner side of the stent body 1 and the membrane layer 2 on the outer side of the stent body 1 can be woven into an integrated structure at the ends. Since the inner membrane layer 2 and the outer membrane layer 2 are fixedly connected at the ends respectively, a sealed cavity is formed between the inner membrane layer 2 and the outer membrane layer 2. The stent body 1 is arranged in this sealed cavity to achieve full membrane coverage of the stent body 1, reducing inaccurate release at the joints and lowering the possibility of shunt occlusion caused by bile leakage and the like.

[0029] Due to the different pressures on the inflow side and the outflow side of the shunt channel, the traditional equal-diameter shunt channel is not applicable. In order to increase the portal vein inflow and improve the long-term patency rate of the shunt channel in cases of portal vein thrombosis, the diameters of the covered stents in this embodiment are adaptively changed. The pressure at the inflow end is relatively high, so its diameter is relatively large, while the pressure at the outflow end is relatively low, so its diameter is relatively small compared to the inflow end. The size of the larger end of the covered stent is 10 - 12 mm, and the diameter of the smaller end is 6 - 8 mm. By controlling the diameter of the shunt channel, the shunt blood volume is controlled, and the incidence of hepatic encephalopathy is reduced.

[0030] In this embodiment, an inclined opening 3 is designed at the connection position between the covered stent and the portal vein, increasing the cross-sectional area of the inflow port, facilitating the simultaneous return of the blood of the splenic vein and the superior mesenteric vein, and improving the effect of portal vein shunt and blood pressure reduction.

[0031] In order to achieve precise positioning during the layout of the shunt channel, a radiopaque point structure is introduced in this embodiment. The radiopaque point refers to a marker point visible under X-ray, which is used to assist the doctor in positioning or confirming the position of the instrument. A first radiopaque point 4 is provided at the connection position between the covered stent and the inferior vena cava, and a second radiopaque point 5 with the same inclination direction as the inclined opening 3 is provided at the inclined opening 3. The second radiopaque point 5 is designed in a linear shape, which can smoothly locate the inclined plane direction during the operation. It is more conducive to the variable-diameter design (the diameter of the inflow end is large, and the diameter of the outflow end is small): increasing the blood inflow volume and reasonably adjusting the shunt volume at the outflow end. The first radiopaque point 4 is arranged obliquely, and one end points to the inferior vena cava, so that the first radiopaque point 4 can clearly locate the outlet position of the shunt channel. Both radiopaque points can use metal markers, such as metal wires or metal strips, which are very conspicuous under X-ray and are commonly used for positioning and confirming the position of the instrument. Contrast agents, such as iodine-based contrast agents and gadolinium-based contrast agents, can also be used to enhance the visibility of the structure in the image.

[0032] In this embodiment, the film covering layer 2 is formed by spiral weaving, which can have tiny voids or micropores to increase the overall flexibility of the covered stent; the film covering layer 2 uses an E-PTFE membrane, that is, an expanded polytetrafluoroethylene membrane, which is a polytetrafluoroethylene material treated by a special process. The E-PTFE membrane is a material with a highly stretched microporous structure. The characteristic of this material is that a large number of micropores are formed inside, making the material have various excellent properties such as air permeability, waterproofness, and biocompatibility. The stent body in this embodiment is a fully covered stent structure, reducing the inaccuracy of release at the connection and reducing the possibility of shunt occlusion caused by bile leakage and the like.

[0033] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A stent graft, characterized in that: include: The diameter of the bracket body gradually decreases from one end to the other end, and the end of the bracket body with a larger diameter is provided with an oblique opening; The coating layer is fixedly arranged on the inner side and the outer side of the stent body. The coating layer is made of a woven structure. The space surrounded by the coating layer on the inner side of the stent body forms a flow diversion channel.

2. The stent graft according to claim 1, characterized in that: The coating layer includes an inner coating layer and an outer coating layer, and the inner coating layer and the outer coating layer completely wrap the stent body.

3. The stent graft according to claim 2, characterized in that: The inner layer coating and the outer layer coating are fixedly connected at the ends to form a closed cavity, and the stent body is located in the closed cavity.

4. The stent graft according to claim 1, characterized in that: The weaving pattern of the coating layer is a wavy structure or a spiral structure.

5. The stent graft according to claim 4, characterized in that: The coating layer has voids or micropores.

6. The stent graft according to claim 1, characterized in that: The diameter of the larger end of the stent body is 10-12 mm.

7. The stent graft according to claim 6, characterized in that: The diameter of the smaller end of the stent body is 6-8 mm.

8. The stent graft according to claim 3, characterized in that: A first developing point is provided at the end of the stent body with a smaller diameter. The first developing point is located outside the coating layer. The first developing point is arranged obliquely, and one end thereof points to the inferior vena cava.

9. The stent graft according to claim 1, characterized in that: A second developing point is provided at the end of the bracket body with a larger diameter, the second developing point is located outside the coating layer, and the plane where the second developing point is located is parallel to the plane where the oblique opening is located.

10. The stent graft according to claim 1, characterized in that: The support body is a hollow structure or a hinged structure.

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