Door body shunting covered stent and stent system

Abstract

The utility model relates to the technical field of door shunting, in particular to a door shunting covered stent and a stent system. The door body shunting covered stent comprises a stent body, the periphery of the stent body is covered with a covering part, and the covering part completely surrounds the stent body in the circumferential direction; the area, covered by the coating piece, of the stent body serves as a variable-diameter area, and the yield strength of the coating piece area corresponding to the variable-diameter area is larger than the acting force applied to the coating piece when the variable-diameter area is subjected to self-expansion. After the portal shunt covered stent is implanted into a human body, the variable-diameter area is expanded through the balloon when necessary. When the wrapping part is expanded and the expansion force is greater than the yield strength of the wrapping part, accurate expansion to the expansion size of the balloon can be realized, so that the size of the variable-diameter area is within the maximum diameter, and the expanded size can be accurately controlled.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of portal shunt, specifically relates to a portal shunt covered stent and stent system. BACKGROUND

[0002] Portal shunt is a surgical procedure for treating complications of portal hypertension. It mainly reduces the pressure of the portal vein by establishing a collateral circulation of the hepatic portal vein, and is used to treat complications such as hypersplenism, esophageal and gastric fundus varices rupture, intractable ascites, etc. caused by portal hypertension. Transjugular intrahepatic portosystemic shunt (TIPS) uses percutaneous puncture to puncture the right internal jugular vein, and places an expandable metal stent between the portal vein branch and the hepatic vein through the jugular vein to establish a portal shunt in the liver, thereby reducing the pressure of the portal vein and preventing complications of portal hypertension.

[0003] In the TIPS stent, when the shunt channel is expanded to the same diameter as the shunt stent, it is easy to cause the stent to shift. When the shunt channel is expanded to be thinner than the diameter of the covered stent to solve the problem of stent shifting, under the action of the radial support force of the stent itself, the shunt channel will expand by itself until the diameter of the shunt channel approaches the diameter of the stent itself. This makes the originally appropriate shunt volume become too large, causing blood ammonia to rise and the liver's processing of portal vein blood to further decrease, leading to severe hepatic encephalopathy and liver failure. When the diameter of the shunt stent is too small, it will result in insufficient shunting, so that the disease cannot achieve the expected effect, and a new shunt channel needs to be established again, which not only increases the cost of the operation but also may fail to adjust the appropriate portal shunt volume, leading to treatment failure.

[0004] The portal shunt covered stent in the prior art is a straight stent, and the required diameter specification needs to be determined and selected after the stent is implanted in the human body. However, due to differences in age, body size, etc. of patients, the size of the applicable portal shunt covered stent is different, which makes it difficult to select the diameter specification of the portal shunt covered stent, and problems will be caused if the diameter of the stent implanted in the human body is too large or too small. UTILITY MODEL CONTENTS

[0005] Therefore, the technical problem to be solved by the utility model is to overcome the defect of difficulty in selecting the diameter specification of the portal shunt covered stent in the prior art, so as to provide a portal shunt covered stent, a manufacturing method of the portal shunt covered stent, and a stent system.

[0006] In order to solve the above technical problems, the utility model provides a portal shunt covered stent, which comprises:

[0007] A stent body, an outer periphery of which is covered by a cladding member, and the cladding member completely surrounds the stent body in the circumferential direction;

[0008] The area of the stent body covered by the covering member includes at least two sections of the fixed-diameter area and the variable-diameter area arranged between the two adjacent sections of the fixed-diameter area, and the yield strength of the area of the covering member corresponding to the variable-diameter area is greater than the force applied to the covering member when the variable-diameter area is self-expanded.

[0009] Optionally, the stent body includes a bare stent section and a covered stent section, and the bare stent section is arranged at the front end of the covered stent section, and the covering member covers the covered stent section.

[0010] Optionally, the covering member covers the stent body in the axial direction.

[0011] Optionally, the covered stent section is spirally woven by the braided wires in a V shape.

[0012] Optionally, the bare stent section is woven by the braided wires in a V shape and staggered hook connection, and the contact between the braided wires forms a hanging part.

[0013] Optionally, the stent body is provided with a positioning mark, and the positioning mark is located at the two ends of the covering member.

[0014] Optionally, the positioning mark is fixedly connected with the stent body.

[0015] Optionally, the covering member includes a first covering section and a second covering section connected in sequence, the first covering section is arranged corresponding to the fixed-diameter area, and the second covering section is arranged corresponding to the variable-diameter area.

[0016] Optionally, the covering member includes a first covering sleeve and a second covering sleeve, the first covering sleeve is sleeved outside the stent body, and the second covering sleeve is sleeved and installed outside the first covering sleeve or between the first covering sleeve and the stent body, and the second covering sleeve is arranged corresponding to the variable-diameter area.

[0017] Optionally, a transition diameter area is arranged between the fixed-diameter area and the variable-diameter area, the diameter of the transition diameter area is smaller than the diameter of the fixed-diameter area, and the diameter of the variable-diameter area is not greater than the diameter of the transition diameter area.

[0018] Optionally, an inner chamfer or an inner fillet transition is arranged between the transition diameter area and the fixed-diameter area, and an outer chamfer or an outer fillet transition is arranged between the transition diameter area and the variable-diameter area.

[0019] Optionally, when the stent body is delivered to the human body, after the stent body is delivered to the position and the outer sheath is withdrawn, one end of the covered stent section away from the bare stent section remains in a constrained state, and the other end of the covered stent section connected with the bare stent section is in a trumpet shape.

[0020] The utility model also provides a kind of production method of door body shunt covered stent, comprising the following steps:

[0021] fabricating the stent body;

[0022] pre-expanding the covering member to a preset diameter, so that the diameter of the covering member at the position corresponding to the constant diameter area is greater than the diameter of the covering member at the position corresponding to the variable diameter area;

[0023] sleeving the covering member on the outer periphery of the stent body, so that the diameter of the variable diameter area of the stent body is reduced to the preset diameter under the action of the covering member.

[0024] The utility model also provides a support system, including shunt support and reduce flow support, reduce flow support is suitable for coaxial and is arranged in the intracavity of shunt support;

[0025] The shunt support and the reduce flow support are both door body shunt film covering supports according to the utility model.

[0026] The utility model technical scheme has the following advantages:

[0027] 1. The door body of the utility model provides a shunt film covering support, including support body, its outer periphery is covered with cladding piece, the cladding piece is plastic deformation under external force; The area of support body covered by cladding piece includes at least two sections of interval setting fixed diameter area and variable diameter area between two adjacent fixed diameter area. The diameter of the support body is constrained by the cylindrical cladding piece on the outside, so that the support remains in a compressed state after implantation. Before the shunt film covering support is implanted into the human body, the support body and the cladding piece are compressed as a whole. After implantation into the human body, the support body self-expands and unfolds. The fixed diameter area of the support body self-expands to the maximum size. Due to the restriction of the cladding piece, the variable diameter area of the support body self-expands to the set constraint size. If the portal vein pressure does not reach the expected level or if the shunt passage needs to be enlarged due to other reasons after surgery, the balloon can be used to expand the variable diameter area. The high pressure of the balloon expansion causes the cylindrical cladding piece to expand circumferentially. The cladding piece is designed to be in a yield state at the minimum diameter. When the cladding piece is expanded, the expansion force is greater than the yield strength of the cladding piece, which can achieve precise expansion to the size of the balloon, thereby achieving precise control of the size of the variable diameter area after expansion within the maximum diameter. At the same time, due to the yield state of the cladding piece, the cladding piece will not elastically retract after expansion. Under the limiting action of the cladding piece, the original diameter of the variable diameter area of the support body is consistent with the maximum diameter. The variable diameter area can still maintain good radial support force after expansion, thereby avoiding the loss of shunt passage due to liver compression. The yield force value of the cylindrical cladding piece is much greater than the chronic outward radial force of the support body at this diameter size, which prevents the cladding piece from deforming when the force exerted by the support body on the cladding piece is greater than the yield strength of the cladding piece. The cladding piece is prevented from being slowly expanded by the radial support force of the support body, ensuring the stability of the diameter restriction of the cladding piece on the variable diameter area. The support body of the variable diameter area can maintain the size stability of the variable diameter area before and after expansion, so that the variable diameter area will not protrude outward due to the radial force of the support body, nor will it be crushed by external human tissue. The cladding piece will not elastically retract after expansion. By setting the variable diameter area on the support body, the diameter of the support can be more conservative, which can effectively avoid the risk of incorrect selection of support specifications. After the shunt film covering support is implanted, a balloon with the same diameter as the minimum diameter is used to expand the variable diameter area of the support body. Then measure whether the portal vein pressure reaches the expected range. If the pressure is lower than expected, you can choose a balloon with the appropriate diameter specification based on the existing pressure value, the expected pressure, and the reduced pressure value to expand the shunt film covering support. If it still does not meet the requirements, you can choose a larger diameter balloon for further expansion. Similarly, if the shunt passage needs to be enlarged due to postoperative recurrent gastrointestinal bleeding or disease progression, you can choose a balloon with a diameter larger than the minimum diameter of the variable diameter area to expand the variable diameter area.

[0028] 2. The door shunt covered stent provided by the utility model, the stent body includes a bare stent section and a covered section, the bare stent section is arranged at the front end of the covered section, and the covering member is arranged on the covered section. By arranging the stent body as the bare stent section covered with a covering member, when the door shunt covered stent is implanted in the human body, the bare stent section is arranged towards the front section, the bare stent section has good flexibility and can well conform to the angle between the shunt passage and the portal vein, so that the shunt passage formed in the stent body is prevented from being folded, occluded or capped.

[0029] 3. The door shunt covered stent provided by the utility model, when the outer tube of the delivery system is retracted, one end of the covered section connected with the bare stent section is trumpet-shaped. When the trumpet-shaped expanded covered section is pulled to the junction of the portal vein and the liver parenchyma, a clear touch can be felt, so that the delivery system is stopped after being pulled, the covered section is ensured to be less deep into the portal vein, and the covered section is prevented from affecting the perfusion of the liver vein caused by the covered section blocking the image of the portal vein. Meanwhile, the covering member extends out of the liver parenchyma, so that the bare stent section is prevented from entering the liver parenchyma and causing the shunt passage to be narrowed or occluded due to the growth of the liver tissue into the shunt passage.

[0030] 4. The stent system provided by the utility model comprises a shunt stent and a flow reduction stent, the flow reduction stent is adapted to be coaxially arranged in the inner cavity of the shunt stent, and the shunt stent and the flow reduction stent are the door shunt covered stent provided by the utility model. When the liver function of some patients is improved after shunt, the shunt flow needs to be reduced to achieve better postoperative effect. When gastrointestinal hemorrhage is caused by excessively high portal vein pressure, the portal vein pressure needs to be quickly and greatly reduced to achieve gastrointestinal hemostasis. After the gastrointestinal tract is completely hemostatic and stable, the shunt flow needs to be reduced to maintain liver perfusion and reduce the risk of hepatic encephalopathy, and there is a lack of effective equipment to reduce the portal shunt flow. At this time, the flow reduction stent is implanted in the inner cavity of the previously implanted shunt stent to reduce the portal shunt flow and maintain sufficient liver perfusion and reduce blood ammonia. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0032] Figure 1 It is a structural schematic view of the door shunt covered stent provided in the embodiments of the utility model.

[0033] Figure 2The weaving process schematic view of the support body provided in the embodiment of the utility model.

[0034] Figure 3 The structure schematic view of the support body of the shunt support provided in the embodiment of the utility model.

[0035] Figure 4 The schematic view of the positioning mark provided in the embodiment of the utility model.

[0036] Figure 5 The schematic view of another positioning mark provided in the embodiment of the utility model.

[0037] Figure 6 The structure schematic view of the bare support of the flow reduction support provided in the embodiment of the utility model.

[0038] Figure 7 The structure schematic view of the support body of the flow reduction support provided in the embodiment of the utility model.

[0039] Figure 8 The structure schematic view of the flow reduction support provided in the embodiment of the utility model.

[0040] Figure 9 The structure schematic view of another support body of the flow reduction support provided in the embodiment of the utility model.

[0041] Figure 10 The structure schematic view of the support body of another flow reduction support provided in the embodiment of the utility model after being connected with the covering member.

[0042] Figure 11 The structure schematic view of another flow reduction support provided in the embodiment of the utility model.

[0043] Figure 12 The structure schematic view of the wrapping film provided in the embodiment of the utility model.

[0044] Figure 13 The relative position schematic view of the unwrapped state of the wrapping film and the door body shunt covering film support provided in the embodiment of the utility model.

[0045] Figure 14 The structure schematic view of the inner tube head provided in the embodiment of the utility model.

[0046] Figure 15 The state schematic view of the door body shunt covering film support being wrapped by the wrapping film provided in the embodiment of the utility model.

[0047] Figure 16 The structure schematic view of the conveying system provided in the embodiment of the utility model.

[0048] Figure 17 for Figure 16 A magnified view of a portion of point A, showing a schematic diagram of the connection between the fixing pin and the bare support segment.

[0049] Explanation of reference numerals in the attached drawings: 1. Support body; 101. Bare support section; 102. Covered section; 1021. Fixed diameter area; 1022. Variable diameter area; 2. Covering component; 201. First covering sleeve; 202. Second covering sleeve; 3. Positioning mark; 4. Braided wire; 5. Braided post; 6. Inner tube; 7. Constraint piece; 8. Guide wire cavity; 9. Conical head; 10. Fixing ring; 11. Fixing pin; 12. Pull wire. Detailed Implementation

[0050] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0051] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0053] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0054] Example 1

[0055] Figures 1 to 17The illustration shows a shunt stent with a membrane covering provided in this embodiment, comprising a stent body 1 and a covering 2 covering the stent body 1. The stent body 1 can be a metal stent, a biodegradable stent, or a medical stent made of other materials. The covering 2 and positioning marks 3 are provided on the stent body 1. The inner cavity of the stent body 1 serves as a shunt channel. The covering 2 has a membrane structure and is fitted over the stent body 1. The diameter of the shunt channel is expandable.

[0056] like Figure 1 As shown, the stent body 1 includes a bare stent segment 101 and a covered segment 102. A covering member 2 covers the outer periphery of the stent body 1. The area of ​​the stent body 1 covered by the covering member 2 is the covered segment 102. The bare stent segment 101 is located at the front end of the covered segment 102. The covered segment 102 includes at least two spaced fixed-diameter regions 1021 and a variable-diameter region 1022 located between two adjacent fixed-diameter regions 1021. The diameter of the variable-diameter region 1022 is not greater than the diameter of the fixed-diameter region 1021. The yield strength of the region of the covering 2 corresponding to the variable diameter region 1022 is greater than the force applied to the covering 2 when the variable diameter region 1022 expands on itself, so that the variable diameter region 1022 can be wrapped and confined to a predetermined diameter by the covering 2 when no external force is applied. After the variable diameter region 1022 is expanded by an external force greater than the yield strength of the covering 2 and the region corresponding to the variable diameter region 1022, the covering 2 and the region corresponding to the variable diameter region 1022 undergo plastic deformation and expand together, thus confining the diameter of the variable diameter region 1022 to another predetermined diameter, so as to realize the controllable adjustment of the inner diameter of the variable diameter region 1022 of the support body 1.

[0057] In this embodiment, as Figure 2 As shown, the support structure, which serves as the support body 1, is woven from braided wires 4. During the weaving process, braided posts 5 are set at the corners of the braided wires 4. The coated section 102 is woven from the braided wires 4 in a V-shaped spiral; the bare support section 101 is woven from the braided wires 4 in a V-shaped, interlaced pattern, with the contact points between the interlaced braided wires 4 hooking together to form a hook-up part. The support body 1 is formed by repeatedly winding a single braided wire 4 around multiple braided posts 5.

[0058] like Figures 3 to 5 As shown, during the weaving process of the support structure 1, which serves as the support body, positioning marks 3 are fixedly set at corresponding positions to indicate the boundary positions of the covered section 102. The positioning marks 3 can be dot-shaped or ring-shaped, or the positioning marks 3 at one end of the covering 2 can be dot-shaped and the positioning marks 3 at the other end can be ring-shaped.

[0059] like Figures 6 to 8As shown, the film segment 102 is divided into a variable diameter zone 1022 and a fixed diameter zone 1021. X-ray opaque positioning marks 3 are provided on the edges of the film segment 102. The portal shunt covered stent is designed with controllable diameter, and the variable diameter zone 1022 can be expanded by a balloon or the like when necessary, and the size can be kept stable for a long time after expansion. It can be used as a shunt stent or a flow reduction stent. As a shunt stent, the bare stent segment 101 provided at the distal end of the stent body 1 has good flexibility, which well conforms to the angle of the shunt passage and the portal vein, avoiding the shunt passage being folded, occluded, or capped. The variable diameter zone 1022 has a smaller diameter than the fixed diameter zone 1021. The variable diameter zone 1022 of the shunt stent can be expanded to the same diameter as the fixed diameter zone 1021. When used as a flow reduction stent, the variable diameter zone 1022 of the flow reduction stent is placed inside the shunt stent, i.e., the fixed diameter zones 1021 of the shunt stent and the flow reduction stent are seamlessly overlapped. The diameter of the variable diameter zone 1022 of the flow reduction stent is smaller than that of the variable diameter zone 1022 of the shunt stent. Blood flows through the flow reduction stent but not through the shunt stent. When the variable diameter zone 1022 of the flow reduction stent is expanded to the maximum diameter, it is still smaller than the diameter of the fixed diameter zone 1021 at both ends of the film segment 102. In some other embodiments, as shown in Figures 9 to 11 Another portal shunt covered stent is shown in the schematic diagram of the step of covering the stent body 1 with a covering film. The stent can be entirely composed of the film segment 102, without the bare stent segment 101.

[0060] The portal shunt covered stent can be used as a shunt stent or a flow reduction stent. In this embodiment, the variable diameter zone 1022 of the stent body 1 can be expanded to the same diameter as the fixed diameter zone 1021. In some other embodiments, in order to limit the maximum expansion diameter of the variable diameter zone 1022 and avoid the failure of the flow reduction stent due to the excessively large expansion size, the maximum diameter to which the variable diameter zone 1022 of the stent body 1 can be expanded is smaller than the diameter of the fixed diameter zone 1021. Specifically, a transition diameter zone is provided between the fixed diameter zone 1021 and the variable diameter zone 1022 of the stent body 1. The diameter of the transition diameter zone is smaller than the diameter of the fixed diameter zone 1021, and the diameter of the variable diameter zone 1022 is not greater than the diameter of the transition diameter zone. An inner fillet transition is provided between the transition diameter zone and the fixed diameter zone 1021, and an outer chamfer transition is provided between the transition diameter zone and the variable diameter zone 1022. In some other embodiments, an inner chamfer transition can be provided between the transition diameter zone and the fixed diameter zone 1021, or an outer fillet transition can be provided between the transition diameter zone and the variable diameter zone 1022. When the variable diameter zone 1022 of the flow reduction stent is expanded, it is expanded to the same diameter as the transition diameter zone.

[0061] In the preparation of the door body shunt covered stent, the stent body 1 is made by weaving method. The stent body 1 can be a metal stent with equal diameter before being covered. In order to distinguish the constant diameter area 1021 and the variable diameter area 1022, the diameter of the variable diameter area 1022 of the stent body 1 after weaving but before being covered (i.e. the covering member 2) is slightly smaller than the diameter of the constant diameter area 1021. The shape of the door body shunt covered stent is determined by the metal stent. The cylindrical film structure of the covering member 2 is pre-expanded to a preset diameter by the balloon, so that the diameter of the covering member 2 at the corresponding position of the constant diameter area 1021 is greater than the diameter of the covering member 2 at the corresponding position of the variable diameter area 1022. Then the covering member 2 is sleeved on the outer periphery of the stent body 1, so that the diameter of the variable diameter area 1022 of the stent body 1 is reduced to the preset diameter under the action of the covering member 2, that is, the diameter of the variable diameter area 1022 is limited by the covering member 2 with high yield strength.

[0062] In this embodiment, the covering member 2 includes a first covering sleeve 201 and a second covering sleeve 202. The first covering sleeve 201 is sleeved outside the stent body 1, and the second covering sleeve 202 is sleeved and installed outside the first covering sleeve 201 or between the first covering sleeve 201 and the stent body 1. The second covering sleeve 202 is arranged corresponding to the variable diameter area 1022. The first covering sleeve 201 is a conventional covering film for wrapping the stent body 1 to form a flow passage, and the yield strength of the second covering sleeve 202 is greater than the force exerted on the covering member 2 when the variable diameter area 1022 self-expands. In some other embodiments, the covering member 2 can also have a single-layer structure, including a first covering segment and a second covering segment connected in sequence. The first covering segment is arranged corresponding to the constant diameter area 1021, and the second covering segment is arranged corresponding to the variable diameter area 1022. The first covering segment is a conventional covering film, and the yield strength of the second covering segment is greater than the force exerted on the covering member 2 when the variable diameter area 1022 self-expands.

[0063] As shown in Figure 12 and 13 Before the door body shunt covered stent is delivered into the human body, the door body shunt covered stent and the delivery system need to be assembled together. The covering segment 102 of the stent body 1 is mostly sized by the restraining piece 7. The door body shunt covered stent fixed by the restraining piece 7 is compatible with the 10F specification TIPS puncture system outer sheath (the specification in this embodiment can have multiple specifications, and this specification is only used for demonstration). When the stent needs to be released, the restraining piece 7 is released by pulling the rear pull line 12, so that the restraining piece 7 automatically expands, thereby realizing the expansion and release of the door body shunt covered stent.

[0064] As shown in Figures 14-17As shown, the delivery system of the door body shunt covered stent comprises an inner tube 6, the inner cavity of the inner tube 6 is a guide wire cavity 8, the guide wire cavity 8 is suitable for the guide wire to pass through, in order to facilitate the advancement in the human body, the front end of the inner tube 6 is provided with a tapered head 9, the outer wall of the inner tube 6 is provided with a fixed ring 10 at a position close to the front end, the fixed ring 10 is fixedly connected with a fixed pin 11, the fixed pin 11 extends towards the front end of the inner tube 6, the fixed pin 11 is suitable for being inserted into the hanging part of the bare stent section 101, so as to drive the door body shunt covered stent to move, or to position the stent body 1 when the door body shunt covered stent is released. The bare stent section 101 is hung on the delivery system core shaft, so that the product has good deliverability in the delivery process. When the delivery system is withdrawn, the inner tube 6 is separated from the bare stent section 101 with the fixed pin 11, so as to realize the separation of the delivery system and the door body shunt covered stent.

[0065] Specifically, in the TIPS operation process, first, the jugular vein is punctured, and a 10F sheath tube is placed into the inferior vena cava behind the liver, a loading catheter is placed into the right hepatic vein opening in the sheath tube, the outlet direction of the loading catheter is adjusted, then a puncture catheter with a puncture needle is guided into the loading catheter, the puncture needle is used to puncture the liver to enter the left branch of the portal vein or the right branch of the portal vein, the puncture catheter is exchanged by using a guide wire, and the guide wire is adjusted to extend to the main trunk of the portal vein, the splenic vein or the superior mesenteric vein, then the sheath tube and the loading catheter are pushed into the main trunk of the portal vein along the guide wire. The assembled portal shunt covered stent and inner tube 6 are placed into the lumen of the loading tube along the guide wire, and the bare stent section 101 of the stent body 1 at the front end is first placed into the main trunk of the portal vein. After the portal shunt covered stent is delivered to the position in the human body, the stent can be pulled back through tactile positioning, that is, the sheath tube and the loading catheter of the delivery system are retracted to release the stent semi, at this time, the stent body 1 starts to expand radially from the bare stent section 101 under the action of self-expanding force, and since the rest of the covered stent section 102 is kept in a compressed state by the constraint piece 7, the rear part of the covered stent section 102 can still be kept in a constrained state, the end of the covered stent section 102 adjacent to the bare stent section 101 expands to a bell shape, so that the portal shunt covered stent can still be pulled back through the delivery system to determine the release position through tactile feeling (when the bell-shaped expanded covered stent section 102 is pulled to the junction of the portal vein and the liver parenchyma, a clear tactile feeling will be felt), and when the tactile feeling is clear, the delivery system is stopped, so as to ensure that the covered stent section 102 is not too deep in the portal vein, and avoid that the covered stent section 102 blocks the image of the portal vein and affects the perfusion of the portal vein to the hepatic vein. At the same time, it is ensured that the covered stent section 102 extends out of the liver parenchyma, and avoids that the bare stent section 101 enters the liver parenchyma and grows into the shunt passage to cause the shunt passage to be narrowed or occluded, so as to solve the problem that in the portal shunt operation, the junction of the portal vein and the liver parenchyma cannot be accurately positioned, and the liver moves during the breathing process to cause inaccurate positioning. The delivery system fixes the bare stent section 101, so that the delivery and release processes are more relaxed and stable, avoid that the portal shunt covered stent is accumulated due to insufficient axial support of the stent itself during the delivery and release processes, so as to cause the delivery and release force to be too large or difficult, and also avoid that the release position is not accurate due to the backward movement of the stent during the release process. After the end of the portal shunt covered stent is positioned, the loading catheter, the sheath tube and the inner tube 6 are retracted in turn, and the pull wire 12 on the constraint piece 7 is pulled to automatically expand the constraint piece 7, and then the expansion of the portal shunt covered stent is realized. Finally, the variable diameter zone 1022 of the stent body 1 is expanded by a balloon, so that the inner diameter of the variable diameter zone 1022 is expanded to a predetermined diameter. Thus, a blood flow passage of the portal vein-portal shunt covered stent-hepatic vein is established, so that part of the blood flow of the portal vein directly enters the heart through the hepatic vein without being metabolized by the liver, thereby reducing the pressure of the portal vein.When it is necessary to increase the inner diameter of the portal shunt covered stent, the variable diameter zone 1022 of the stent body 1 is expanded to another larger predetermined diameter by a larger diameter balloon; when it is necessary to reduce the inner diameter of the portal shunt covered stent, another portal shunt covered stent is placed inside the stent body 1, ensuring that the fixed diameter zone 1021 of the stent body 1 of the newly placed portal shunt covered stent is in contact with the fixed diameter section of the stent body 1 of the previously placed portal shunt covered stent, and the variable diameter zone 1022 of the stent body 1 of the newly placed portal shunt covered stent is expanded to another smaller predetermined diameter by another balloon with a smaller outer diameter.

[0066] The portal shunt covered stent provided by the embodiment adopts multiple diameter specifications, and compared with the existing marketed products, multiple smaller diameter specifications are added, and the diameter expandable technology is adopted, so that the selection of the covered stent is simple and feasible in the transjugular intrahepatic portosystemic shunt. The portal shunt covered stent can be used as a flow-reducing stent placed inside the shunt stent, so that when the intrahepatic portosystemic shunt is faced with excessive shunt, poor liver perfusion, and severe hepatic encephalopathy, a flow-reducing stent is implanted in the previously implanted portal shunt covered stent to reduce the portal flow and maintain sufficient liver perfusion and reduce blood ammonia. Specifically, for the existing marketed portal shunt covered stent, the overall shunt of Asians is too large, and the shunt of some patients with intrahepatic salvageable patients is too large, multiple smaller diameter specifications are added compared with the existing marketed products, and multiple diameter types of portal shunt covered stents are designed as shunt stents, and during the operation, the appropriate diameter of the portal shunt covered stent can be selected according to the portal vein pressure, the patient's body type, and the different stages of the disease.

[0067] In view of the fact that although the stent diameter can be selected according to the portal vein pressure, body size and disease stage, the appropriate shunt stent specification cannot be accurately selected, a local diameter-expandable variable diameter zone 1022 is arranged on the film section 102 of the stent body 1 of the portosystemic shunt covered stent, so that the minimum diameter of the stent can be more safely selected. When the portosystemic shunt covered stent is implanted into the human body, if the portal vein pressure after shunt is still too high, the variable diameter zone 1022 is expanded by a balloon of appropriate diameter, and the channel is expanded to the target diameter through the balloon diameter specification and expansion pressure. Thus, the problems of excessive shunt caused by too large diameter selection of the conventional portosystemic shunt covered stent and insufficient shunt caused by too small diameter selection are avoided. Specifically, the stent body 1 is first made into an equal-diameter tubular shape, with a front end being a flexible bare stent section 101, a middle part being a film section 102, and a tail end being a film section 102 continuously arranged in the middle or another bare stent section 101. A sleeve composed of a covering member 2 with the same minimum diameter as the desired minimum diameter is arranged on the film section 102 in a compressed state through a composite film process, and then the covering member 2 is connected with the stent body 1 through its own support force or through heat melting, bonding, suturing, etc. Alternatively, a sleeve of the covering member 2 with a smaller diameter than the preset minimum diameter of the stent can be arranged on the stent body 1, and the stent body 1 is expanded by a balloon to stretch the covering member 2 to the yield state in the circumferential direction, so that the yield strength of the covering member 2 is greater than the chronic outward radial support force of the stent at the diameter size. The yield state is also called the yield stage. In material mechanics, when the stress exceeds a certain value, the material will permanently deform, and this process is irreversible. In this way, the sleeve composed of the covering member 2 can overcome the chronic outward radial support force of the stent body 1, so that the variable diameter zone 1022 can be kept at the set size for a long time. Similarly, after the variable diameter zone 1022 is expanded after the portosystemic shunt covered stent is implanted into the human body, the radial support force of the stent body 1 can also be overcome, so that the variable diameter zone 1022 can be kept at the expanded size. At the same time, because the variable diameter zone 1022 can keep the diameter stable for a long time, the problem of excessive shunt caused by the diameter variation of the shunt channel after the conventional portosystemic shunt covered stent surgery is effectively avoided.

[0068] The conventional portal shunt covered stent is a straight stent. If the stent is directly expanded to the designed diameter of the stent, the interaction force between the stent and the channel will be relatively soft, and the stent is prone to displacement due to blood flow, improper operation and other factors before the stent and the channel are combined stably, thereby causing treatment failure, channel stenosis and other problems. The current common solution in clinical practice is to control the stent expansion to be about 2 mm smaller than the diameter of the stent. Although this method solves the problem of stent displacement, it brings a new problem that under the action of the chronic outward force of the stent, in most cases, after the shunt channel is expanded, the shunt channel will expand to close to the designed diameter of the stent under the action of the stent, the portal shunt is too large, too much blood is not treated by the liver, the blood ammonia content in the blood is too high, and the hepatic encephalopathy is caused. The sleeve of the covering part 2 restricts the diameter of the covered section 102 outside the stent body 1, so that the variable diameter area 1022 of the stent body 1 remains in a compressed state in the natural state or after implantation. If the portal vein pressure does not reach the expected value after implantation or needs to be increased due to other reasons after the operation, the variable diameter area 1022 is expanded by a balloon, and the sleeve is expanded by the high pressure of the balloon expansion. Specifically, by designing the covering part 2 to be in a yield state at the minimum diameter, the covering part 2 can be accurately expanded to the size of the balloon when the expansion force is greater than the yield strength of the covering part 2. Thus, the size of the variable diameter area 1022 of the stent body 1 can be accurately controlled within the maximum diameter after expansion, and the sleeve will not elastically retract after expansion because the covering part 2 is in a yield state. The original diameter of the fixed diameter area 1021 of the stent body 1 is consistent with the maximum diameter, and the fixed diameter area 1021 will still maintain good radial support after the expansion of the variable diameter area 1022, thereby avoiding the loss of the shunt channel caused by the extrusion of the liver substance. The force value required for the yield of the covering part 2 is much greater than the chronic outward radial force of the stent body 1 at this diameter size, so that the variable diameter area 1022 of the covered section 102 can maintain the size stability of the variable diameter area 1022 before and after expansion, and will not protrude outward due to the radial force of the stent body 1 or be collapsed by the extrusion of the liver substance, and will not elastically retract after expansion.

[0069] During the operation, the diameter of the portal shunt covered stent can be selected more conservatively to effectively avoid the risk of incorrect stent specification selection. After the portal shunt covered stent is implanted, a balloon with the same diameter as the minimum diameter can be used to expand the channel, and then the portal vein pressure is measured to determine whether it reaches the expected range. If the pressure is lower than expected, a balloon with a suitable diameter can be selected according to the existing pressure value, the expected pressure and the reduced pressure value to expand the variable diameter area 1022. If it is still not satisfied, a balloon with a larger diameter can be selected for further expansion.

[0070] Likewise, if postoperatively the shunt needs to be enlarged due to re-bleeding or disease progression, the variable diameter zone 1022 can be dilated with a balloon having a diameter larger than the current minimum diameter of the variable diameter zone 1022, according to the anticipated increased flow rate.

[0071] The portal shunt covered stent is also designed to have a controllable diameter when used as a flow-reducing stent, to avoid excessive flow reduction that can cause ascites and hepatic encephalopathy, and to facilitate the selection of a stent diameter that is not too small or too large. In some other embodiments, the stent body 1 of the flow-reducing stent can not have a bare stent segment 101.

[0072] The covered stent segment 102 of the portal shunt covered stent provided in this embodiment has a variable diameter zone 1022, which is required to have an expandable diameter and to remain stable after expansion for a long period of time, to reduce the risk of stent diameter selection and to reduce the risk of excessive shunt flow. The flow-reducing stent is used to reduce shunt flow to maintain liver perfusion during surgery or to reduce shunt flow after surgery due to severe hepatic encephalopathy or to reduce shunt flow during the recovery of liver function, to address the lack of remedial measures for excessive shunt flow or severe hepatic encephalopathy.

[0073] The diameter of the existing portal shunt covered stent is too large, and the existing stent is imported from abroad and is designed for European and American body types. The smallest diameter specification can only meet the needs of part of the Chinese population, and another part of the population will still suffer from the side effects of excessive shunt flow even if the smallest diameter specification is selected. In the treatment of portal hypertension by TIPS, there is a lack of effective remedial measures to reduce portal flow when liver perfusion is poor due to excessive shunt flow and severe hepatic encephalopathy. This embodiment provides multiple different diameter specifications to meet the needs of small-diameter stents for Asian populations. The smallest diameter of the existing TIPS stent on the market is 8 mm, and this embodiment provides diameter specifications of 5-7 mm, 6-8 mm, 7-9 mm, and 8-10 mm. The rich diameter specifications can better meet the clinical needs and reduce the incidence of hepatic encephalopathy.

[0074] The existing portal shunt covered stent has a covered film length of only 8 cm. For some patients, two or three stents need to be implanted to achieve the isolation of the covered film to the shunt passage due to the long TIPS channel. This increases the burden on the patient and may cause channel stenosis due to stent overlap. The portal shunt covered stent provided in the embodiment has multiple specifications for length settings, so that the patient can use one portal shunt covered stent to establish a shunt passage as much as possible, reduce the cost of surgery, and reduce the risk of fatigue caused by stent overlap. At the same time, it can also avoid the risk of blood flowing from the inferior vena cava puncture port into the abdominal cavity when a second portal shunt covered stent is connected. It can also avoid the risk of the guide wire being pulled out when the delivery system is removed after the first stent is placed, because the guide wire passes through the complete channel that is not supported by the stent. Due to the elastic recoil of the liver tissue, it is difficult to reinsert the guide wire into the punctured channel.

[0075] The design concept of the existing portal shunt covered stent is to reduce the pain and risk of gastrointestinal bleeding of patients with severe portal hypertension through TIPS surgery. After decades of development, treatment has been pushed forward. After the discovery of portal hypertension caused by impaired liver function, portal shunt surgery will no longer be performed at the end of the stage. Instead, early treatment can better delay the degree of liver function reduction, reduce the risk of gastrointestinal bleeding, and solve the problem of ascites. At this stage, a finer shunt can reduce the risk of gastrointestinal bleeding, relieve liver ascites, and reduce the risk of hepatic encephalopathy. Maintaining good liver perfusion is beneficial to liver function recovery or stability, and can avoid liver failure.

[0076] Embodiment 2

[0077] The embodiment provides a stent system, which comprises a shunt stent and a flow reduction stent. The flow reduction stent is adapted to be coaxially arranged in the inner cavity of the shunt stent. Both the shunt stent and the flow reduction stent are the portal shunt covered stent described in Embodiment 1.

[0078] When the portal shunt covered stent is used as a flow reduction stent, it is also designed in a controllable diameter form to avoid the risk of causing ascites, hepatic encephalopathy, and the like due to excessive flow reduction. This provides convenience for the selection of the diameter of the flow reduction stent and reduces the risk of excessive flow reduction. In some other embodiments, the stent of the flow reduction stent does not have a bare stent section 101.

[0079] The film-covered segment 102 of the flow-reducing stent has a large diameter at both ends and a thin middle part. The variable diameter zone 1022 is located in the middle part. If necessary, the variable diameter zone 1022 can be further expanded. The flow-reducing stent can be expanded to the maximum diameter, which is still smaller than the diameter of the two ends of the film. The diameter of the two ends of the film is designed to match the maximum diameter of the shunt stent. The flow-reducing diameter can be anchored in the shunt stent, and the diameter of the variable diameter zone 1022 is reduced to reduce the diameter of the passage. When the shunt flow is found to be too low during the operation or after the operation, the variable diameter zone 1022 of the flow-reducing stent can be expanded.

[0080] At the same time, when the liver function is partially improved after the implantation of the shunt stent, there is a need to reduce the shunt flow to achieve better prognosis for the patient; or when gastrointestinal bleeding is caused by high portal vein pressure, it is necessary to quickly and significantly reduce the portal vein pressure to achieve gastrointestinal hemostasis. After the gastrointestinal bleeding is completely stopped and stabilized, there is a lack of effective devices to reduce the portal flow to maintain liver perfusion. By implanting another portal flow-covered stent as a flow-reducing stent in the shunt stent, the above effects can be achieved.

[0081] For the case of reducing the shunt passage during or after the operation, the flow-reducing stent is designed to have a waist drum shape, which can have a bare stent segment 101 or a full film-covered structure. In the same way, a film-covered sleeve with a diameter smaller than the minimum diameter to be set is sleeved on the small waist segment of the compressed flow-reducing film-covered stent, and the sleeve and the stent film are connected by the support force of the stent itself or by bonding, suturing, etc. The variable diameter zone 1022 inside the stent body 1 is expanded, so that the covering member 2 is radially stretched and extended to the yield state. The yield strength of the covering member 2 is greater than the chronic outward radial support force of the stent at that diameter size. In this way, the covering member 2 can overcome the radial support force of the stent, so that the variable diameter zone 1022 remains in the set size state. After implantation, the variable diameter zone 1022 is expanded, which can also overcome the radial support force of the stent body 1, so that the variable diameter zone 1022 remains in the expanded size.

[0082] Obviously, the above embodiments are only examples for the purpose of clear illustration, and are not limitations on the embodiments. Based on the above description, those skilled in the art can make other different forms of changes or modifications. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. A door-type diversion membrane support, characterized in that, include The support body (1) is covered with a covering (2) on its outer periphery, and the covering (2) completely surrounds the support body (1) in the circumference. The area of ​​the support body (1) covered by the covering (2) includes at least two spaced fixed diameter regions (1021) and a variable diameter region (1022) located between two adjacent fixed diameter regions (1021). The yield strength of the region of the covering (2) corresponding to the variable diameter region (1022) is greater than the force exerted on the covering (2) when the variable diameter region (1022) undergoes self-expansion.

2. The door diversion membrane support according to claim 1, characterized in that, The stent body (1) includes a bare stent section (101) and a covered section (102). The bare stent section (101) is located at the front end of the covered section (102), and the covering member (2) is disposed on the covered section (102). Alternatively, the covering (2) may completely cover the support body (1) in the axial direction.

3. The door diversion membrane support according to claim 2, characterized in that, The coated section (102) is made of braided yarn (4) in a V-shaped spiral; And / or, the bare support segment (101) is woven from braided filaments (4) interlaced in a V-shape, with the contact points between the interlaced braided filaments (4) hooking together to form a hanging part.

4. The door diversion membrane support according to any one of claims 1 to 3, characterized in that, The support body (1) is provided with positioning marks (3), which are located at both ends of the covering (2).

5. The door diversion membrane support according to any one of claims 1 to 3, characterized in that, The covering (2) includes a first covering segment and a second covering segment connected in sequence. The first covering segment is correspondingly disposed to the fixed diameter region (1021), and the second covering segment is correspondingly disposed to the variable diameter region (1022). Alternatively, the covering (2) includes a first covering sleeve (201) and a second covering sleeve (202). The first covering sleeve (201) is sleeved outside the support body (1), and the second covering sleeve (202) is sleeved and installed outside the first covering sleeve (201) or the second covering sleeve (202) is sleeved and installed between the first covering sleeve (201) and the support body (1). The second covering sleeve (202) is correspondingly provided with the variable diameter area (1022).

6. The door diversion membrane support according to any one of claims 1 to 3, characterized in that, A transition diameter region is provided between the fixed diameter region (1021) and the variable diameter region (1022). The diameter of the transition diameter region is smaller than the diameter of the fixed diameter region (1021), and the diameter of the variable diameter region (1022) is not greater than the diameter of the transition diameter region.

7. The door diversion membrane support according to claim 6, characterized in that, An inner chamfer or inner fillet is provided between the transition diameter region and the fixed diameter region (1021); an outer chamfer or outer fillet is provided between the transition diameter region and the variable diameter region (1022).

8. The door diversion membrane support according to claim 2 or 3, characterized in that, When the shunt stent is released in the body, after the outer sheath is retracted at the preset release position, the end of the covered section (102) away from the bare stent section (101) remains constrained, and the end of the covered section (102) connected to the bare stent section (101) is flared.

9. A support system, characterized in that, It includes a diversion bracket and a flow reduction bracket, wherein the flow reduction bracket is adapted to be coaxially inserted into the inner cavity of the diversion bracket; Both the diversion bracket and the flow reduction bracket are door diversion coating brackets as described in any one of claims 1 to 8.

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