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Abstract

The invention discloses a stent, and relates to the technical field of interventional medical instruments, the stent comprises a near end, a far end and a bare section, the near end is communicated with inferior vena cava; the far end is communicated with the portal vein; the bare section is located between the near end and the far end and communicates the near end with the far end to jointly form a shunt channel between the inferior vena cava and the portal vein; the bare section can convey part of fluid flowing through the flow dividing channel to the intrahepatic branch blood vessel. According to the stent provided by the invention, part of blood in the shunt channel can enter intrahepatic branch blood vessels, so that liver function recovery is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of interventional medical devices, and particularly to a 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. Currently, after a shunt channel is established using a stent, blood flow cannot enter the intrahepatic branch vessels, which is not conducive to the recovery of liver function. Summary of the Invention

[0003] An object of the present invention is to provide a stent to solve the problems existing in the above-mentioned prior art, so that a part of the blood in the shunt channel can enter the intrahepatic branch vessels, which is conducive to the recovery of liver function.

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

[0005] The present invention provides a stent, comprising:

[0006] A proximal end, which is in communication with the inferior vena cava;

[0007] A distal end, which is in communication with the portal vein;

[0008] A bare segment, located between the proximal end and the distal end, and connecting the proximal end and the distal end to jointly form a shunt channel between the inferior vena cava and the portal vein; the bare segment can transport a part of the fluid flowing through the shunt channel to the intrahepatic branch vessels.

[0009] In one embodiment, the distal end is disposed at or near the bifurcation of the portal vein and the splenic vein, so that the fluid of the splenic vein can enter the stent through the distal end.

[0010] In one embodiment, the cross-section of the proximal end is a ring structure, and a first imaging point is provided at the position where it is in communication with the inferior vena cava.

[0011] In one embodiment, the diameter of the proximal end is smaller than the diameter of the distal end, the bare segment is a hollow frustum-shaped structure, and a second imaging point is provided on the bare segment.

[0012] In one embodiment, the plane where the beveled opening is located is not perpendicular to the axis of the stent.

[0013] In one embodiment, the cross-section of the distal end is a ring structure, and one end of the distal end in communication with the portal vein has a beveled opening, and the present invention forms the beveled opening by adjusting the pitch of the spiral metal stent or the size of the V shape.

[0014] In one embodiment, the beveled opening has a beveled opening edge away from the splenic vein, and at least a part of the projection area of the beveled opening edge facing the splenic vein falls on the extension line of the axis of the splenic vein.

[0015] In one embodiment, a third developer point having the same inclination direction as the beveled opening is provided at the beveled opening.

[0016] In one embodiment, the proximal end includes a metal layer, and a coated film layer is provided on the inner side and the outer side of the metal layer respectively; the distal end structure is the same as the proximal end structure.

[0017] In one embodiment, the bare segment includes the metal layer, and the metal layer is a helically woven hollow structure or a hinge structure.

[0018] In one embodiment, the second developer point is a ring structure, and it is disposed around the connection position between the proximal end and the bare segment.

[0019] In one embodiment, the diameter of the distal end is 10 - 12 mm, and the diameter of the proximal end is 6 - 8 mm.

[0020] In one embodiment, the first developer point is disposed obliquely, and one end thereof points to the inferior vena cava.

[0021] The present invention has achieved the following technical effects compared with the prior art:

[0022] The stent of the present invention is integrally divided into a distal end, a proximal end and a bare segment. The shunt channel jointly formed by the three can enable blood to directly enter the hepatic vein from the portal vein, realizing the shunt function and reducing the pressure of the portal vein. At the same time, the side wall of the bare segment is provided with openings communicating with the intrahepatic branch vessels, so that part of the blood in the shunt channel can enter the intrahepatic branch vessels. Furthermore, while achieving shunt and pressure reduction, the blood flow of the intrahepatic portal vein can be ensured, which is beneficial to the recovery of liver function. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of a stent according to one embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of a partially enlarged structure of a stent according to one embodiment of the present invention;

[0026] Figure 3Schematic diagram of the distal structure of the stent according to one embodiment of the present invention.

[0027] In the figure: 100 - stent, 1 - proximal end, 2 - distal end, 201 - beveled opening, 221 - first membrane, 222 - second membrane, 223 - third membrane, 224 - fourth membrane, 225 - fifth membrane, 230 - polymer adhesive layer, 3 - bare segment, 301 - circular hinge, 4 - first radiopaque marker, 5 - second radiopaque marker, 6 - third radiopaque marker, 7 - nitinol wire. Detailed implementation manners

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] The purpose of the present invention is to provide a stent to solve the problems existing in the above-mentioned prior art, so that a part of the blood in the shunt channel can enter the intrahepatic branch vessels, which is beneficial to the recovery of liver function.

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0031] The Transjugular Intrahepatic Portosystemic Shunt (TIPS) is an interventional therapeutic technique used to treat portal hypertension in patients with liver cirrhosis. TIPS creates a channel connecting the portal venous system and the systemic circulation system within the liver to reduce the pressure of the portal vein, thereby alleviating the related complications caused by portal hypertension. This process is usually completed by an interventional doctor using puncture and catheter techniques guided by X-ray or ultrasound to establish a connection between the portal vein and the hepatic vein. The inventor found that after establishing a covered stent shunt channel between the portal vein and the hepatic vein, although the portal vein pressure can be reduced, the blood in the portal venous system will significantly reduce the intrahepatic portal venous blood flow due to the isolation effect of the covered stent, which is not conducive to liver repair. To solve this problem, the present invention provides a stent, such as Figure 1As shown, it includes a proximal end 1, a bare segment 3, and a distal end 2. The proximal end 1 is used to communicate with the hepatic vein and the inferior vena cava (inferior vena cava anatomical structure); the distal end 2 is used to communicate with the portal vein (portal vein anatomical structure); the bare segment 3 is located between the proximal end 1 and the distal end 2, and the bare segment 3 connects the proximal end 1 and the distal end 2 to jointly form a shunt channel between the inferior vena cava and the portal vein, achieving the effect of reducing portal vein pressure; at the same time, the bare segment 3 is positioned within the intrahepatic portal vein segment, near the position of the hepatic branch vessels (hepatic branch vessels anatomical structure), so that part of the fluid (blood) flowing through the shunt channel can be transported to the intrahepatic branch vessels (intrahepatic branch vessels anatomical structure), which can ensure the blood flow of the intrahepatic portal vein while achieving shunt and blood pressure reduction, and is beneficial to the recovery of liver function.

[0032] In one embodiment, the distal end 2 of the stent 100 is arranged at the bifurcation or nearby area where the splenic vein and the superior mesenteric vein converge into the portal vein, so that the fluid of the splenic vein can enter the lumen of the stent 100 through the distal end 2 of the stent 100. It can be understood that, relative to its proximal end 1, the distal end 2 of the stent 100 has an inclined wide - mouth design (the plane where the inclined mouth is located is not perpendicular to the axis line of the stent), which is beneficial to simultaneously receive the blood of the splenic vein and the superior mesenteric vein, and improve the effect of portal vein shunt and blood pressure reduction. Further, the plane where the inclined mouth is located is not perpendicular to the axis line of the stent 100, and has the following advantages: the inclined wide - mouth at the distal end 2 can increase the function of receiving blood flow, including the blood flow of the splenic vein and the superior mesenteric vein, etc., which is beneficial to improving the long - term patency rate of the shunt - channel stent; the inclined - mouth edge away from the splenic vein, the projection area of the inclined - mouth edge towards the splenic vein at least partially falls on the extension line of the splenic vein axis, so that the blood vessel wall in the portal vein bifurcation area can be supported to the maximum extent to prevent the loss of the lumen at the bifurcation (stenosis or restenosis), and at the same time, it does not affect the blood of the splenic vein from entering the lumen of the stent.

[0033] In one embodiment, the distal end 2 of the stent 100 is arranged at the bifurcation or nearby area between the portal vein (portal vein anatomical structure) and the splenic vein (splenic vein anatomical structure), so that the fluid of the splenic vein can enter the lumen of the stent through the distal end of the stent. It can be understood that, relative to its proximal end 1, the distal end 2 of the stent 100 has an inclined wide - mouth design (the plane where the inclined mouth is located is not perpendicular to the axis line of the stent), which is beneficial to simultaneously receive the blood of the splenic vein and the superior mesenteric vein, and improve the effect of portal vein shunt and blood pressure reduction. Further, the plane where the inclined mouth is located is not perpendicular to the axis line of the stent 100; the inclined wide - mouth at the distal end 2 has an inclined - mouth edge away from the splenic vein, and the projection area of the inclined - mouth edge towards the splenic vein at least partially falls on the extension line of the splenic vein axis, so that the blood vessel wall in the portal vein bifurcation area can be supported to the maximum extent to prevent the loss of the lumen at the bifurcation (stenosis or restenosis), and at the same time, it does not affect the blood of the splenic vein from entering the lumen of the stent; the inclined wide - mouth design at the distal end 2 can effectively avoid the problem of gap leakage between the stent 100 and the blood vessel wall caused by the impact of the splenic vein blood flow on the opposite blood vessel wall of the portal vein.

[0034] In one embodiment, in order to make the integrity of the shunt channel better, the main bodies of the proximal end 1, the bare segment 3 and the distal end 2 thus adopt a metal layer woven into one body. The metal layer is a hollow structure with regular or irregular holes. It is formed by helically winding metal wires into one body. The connection points of adjacent metal wires are of hinge structure, or the connection points of two adjacent metal wires are connected by means such as lapping, riveting or fixed bonding. The structure after the metal wires arranged axially are wound can be an annular structure, a wavy structure, or an intersecting structure. A plurality of metal wires are arranged in sequence along the axis to form an integral metal layer. The metal wires forming the metal layer are made of medical memory alloy or other medical compliant metal materials, and the whole has a certain supporting strength and meets the flexibility requirements.

[0035] In this embodiment, by covering the inner and outer sides of the distal end 2 and the proximal end 1 respectively, and not covering the bare segment 3, the proximal end, the distal end 2 and the bare segment 3 with different overall structures are formed. Since the bare segment 3 is not covered and has a hollow structure, part of the blood flowing through the channel can flow to the intrahepatic branch vessels through the hollow part of the bare segment 3.

[0036] 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 volume and improve the long-term patency rate of the shunt channel in portal vein thrombosis cases, the diameters of the proximal end 1 and the distal end 2 in this embodiment are adaptively changed respectively. The distal end 2 is used as the inflow end with a relatively large pressure, so its diameter is relatively large, while the pressure at the proximal end 1 is relatively small, so its diameter is smaller than that of the distal end 2. For example, the diameter of the distal end 2 can be 10 - 12 mm, and the diameter of the proximal end 1 is 6 - 8 mm. In order to adapt to the different diameter sizes of the proximal end 1 and the distal end 2, the bare segment 3 is designed as a frustum-shaped structure, one end of which matches the diameter of the proximal end 1 and the other end matches the diameter of the distal end 2 to achieve the connection among the three. By controlling the diameter of the shunt channel, the shunted blood volume is controlled, and the incidence of hepatic encephalopathy is reduced.

[0037] On the basis of the above embodiment, the tubular structure formed by the distal end 2 can also be designed as a variable-diameter structure with a diameter gradually decreasing from one end to the other end, and the tubular structure formed by the proximal end 1 can also be designed as a variable-diameter structure with a diameter gradually decreasing from one end to the other end. Thus, the shunt channel jointly formed by the proximal end 1, the bare segment 3 and the distal end 2 is an integral frustum-shaped structure.

[0038] In this embodiment, an inclined opening 201 is designed at the connection position between the distal end 2 and the portal vein, which increases the cross-sectional area of the inflow port, is conducive to simultaneously retracting the blood of the splenic vein and the superior mesenteric vein, and improves the effect of portal vein shunt and blood pressure reduction.

[0039] In the cross-weaving of the bare segment 3 in this embodiment, such as Figure 2The shown stent 100 adopts the circular hinge 301 method, which can not only prevent the displacement of the stent rods after braiding, but also enable the stent rods to have a certain degree of freedom, ensuring the stability of the stent structure and the radial supporting force.

[0040] As Figure 3 shown, the distal end 2 of the stent 100 in this embodiment includes a nitinol wire 7 with a V-shaped spiral structure and an E-PTFE membrane. The thickness of the E-PTFE membrane on the inner and outer sides of the nitinol wire 7 is different; further, the E-PTFE membrane includes a first membrane 221, a second membrane 222 on the outer side of the nitinol wire 7, and a third membrane 223, a fourth membrane 224, and a fifth membrane 225 on the inner side of the nitinol wire 7; each structure is connected into a breathable thin film through a polymer adhesive layer 230. The inner E-PTFE membrane has three or more layers (thicker), which can ensure that the stent has a good inner wall (no damage, smooth, stable inner diameter size), and the outer E-PTFE membrane has two layers to prevent the overall thickness of the stent from being too thick, resulting in poor flexibility of the stent.

[0041] In one embodiment, the membrane thickness of the proximal end 1 of the stent 100 is less than the membrane thickness of the distal end 2 of the stent 100.

[0042] As Figure 1 shown, in order to achieve accurate positioning during the arrangement of the shunt channel, a radiopaque marker structure is introduced in this embodiment. The radiopaque marker refers to a marker point visible under X-rays, which is used to assist doctors in positioning or confirming the position of the instrument. A first radiopaque marker 4 is provided at the position where the proximal end 1 communicates with the inferior vena cava, a second radiopaque marker 5 is provided on the bare segment 3, and a third radiopaque marker 6 with the same inclination direction as the bevel 201 is provided at the bevel 201 of the distal end 2. The third radiopaque marker 6 is designed in a linear shape, which can smoothly locate the bevel direction during the operation, and is more conducive to the variable diameter design (the inflow end has a large diameter and the outflow end has a small diameter): increasing the blood inflow volume and reasonably adjusting the shunt volume at the outflow end. The first radiopaque marker 4 is arranged obliquely, and one end thereof points to the inferior vena cava, so that the first radiopaque marker 4 can clearly locate the outlet position of the shunt channel. The second radiopaque marker 5 is in a ring structure, which is arranged around the connection position of the proximal end 1 and the bare segment 3. The second radiopaque marker 5 can observe the middle position of the connection, facilitating the positioning of the bare segment 3. The three radiopaque markers can adopt metal markers, such as metal wires or metal strip structures, which are very conspicuous under X-rays 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.

[0043] In this embodiment, both the distal end 2 and the proximal end 1 have a structure with an inner and outer layer of film. The film layer of the film-covered section is formed by spiral braiding, which can have tiny voids or gaps to increase the overall flexibility of the stent; the film layer uses an E-PTFE membrane, that is, an expanded polytetrafluoroethylene membrane, which is a polytetrafluoroethylene material processed 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 it, making the material have various excellent properties such as breathability, waterproofness, and biocompatibility. In this embodiment, both the proximal end 1 and the distal end 2 are full-film-covered stent structures, reducing the inaccuracy of release at the connection and reducing the possibility of shunt occlusion caused by bile leakage, etc.

[0044] 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 bracket, characterized in that: include: Proximally, it communicates with the inferior vena cava; distally, it communicates with the portal vein; A bare segment, located between the proximal end and the distal end, and connecting the proximal end and the distal end to form a shunt channel between the inferior vena cava and the portal vein; The bare segment can transport part of the fluid flowing through the shunt channel to the intrahepatic branch vessels.

2. The bracket according to claim 1, characterized in that: The distal end is arranged at or near the bifurcation where the splenic vein and the superior mesenteric vein merge into the portal vein, so that the fluid of the splenic vein can enter the stent through the distal end.

3. The bracket according to claim 1, characterized in that: The cross section of the proximal end is an annular structure, and a first developing point is provided at the position where it is connected with the inferior vena cava. The diameter of the proximal end is smaller than the diameter of the distal end. The bare segment is a hollow frustum-shaped structure, and a second developing point is provided on the bare segment.

4. The bracket according to claim 2, characterized in that: The distal end is a tubular structure, and one end of the distal end communicating with the portal vein has an oblique opening, and the surface where the oblique opening is located is not perpendicular to the axis of the stent.

5. The bracket according to claim 4, characterized in that: The oblique opening is provided with a third developing point in the same inclination direction as the oblique opening; the oblique opening has an oblique opening edge away from the splenic vein, and the projection area of ​​the oblique opening edge toward the splenic vein at least partially falls on the extension line of the splenic vein axis.

6. The bracket according to claim 1, characterized in that: The proximal end includes a metal layer, and coating layers are respectively arranged on the inner side and the outer side of the metal layer; the distal end structure is the same as the proximal end structure.

7. The bracket according to claim 6, characterized in that: The bare segment includes the metal layer, and the metal layer is a spirally woven hollow structure or a hinged structure.

8. The bracket according to claim 3, characterized in that: The second developing point is a ring-shaped structure, which is arranged at the connection position between the proximal end and the bare segment.

9. The bracket according to claim 1, characterized in that: The diameter of the distal end is 10-12 mm, and the diameter of the proximal end is 6-8 mm.

10. The bracket according to claim 1, characterized in that: The first developing point is arranged obliquely, and one end thereof points to the inferior vena cava.

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