Door body shunting covered stent, manufacturing method and stent system

Abstract

The invention relates to the technical field of door shunting, in particular to a door shunting covered stent, a manufacturing method 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 present invention relates to the technical field of portosystemic shunt surgery, and in particular to a portosystemic shunt covered stent, a manufacturing method and a stent system. Background Art

[0002] Portosystemic shunt is a surgical procedure for the treatment of complications of portal hypertension. It is mainly used to reduce the pressure of the portal vein by establishing a collateral circulation of the portal vein, and is used to treat complications such as hypersplenism, esophageal varicose bleeding, and refractory ascites caused by portal hypertension. Transjugular intrahepatic portosystemic shunt (TIPS) uses percutaneous puncture of the right internal jugular vein, inserts an expandable metal stent between the portal vein branch and the hepatic vein through the jugular vein, and establishes a portosystemic shunt in the liver, thereby reducing portal vein pressure and preventing complications of portal hypertension.

[0003] In the TIPS stent, when the expansion of the shunt channel is consistent with the diameter of the shunt stent, it is easy to cause the stent to shift. When the anti-stent shifting is solved by expanding the shunt channel to be thinner than the diameter of the coated stent, the shunt channel will expand automatically under the action of the radial support force of the stent itself until the diameter of the shunt channel is close to the diameter of the stent itself. The originally appropriate shunt volume becomes too large, resulting in increased blood ammonia and further decreased liver processing of portal vein blood, causing severe hepatic encephalopathy and liver failure. When the diameter of the shunt stent is too thin, it will lead to insufficient shunt, so that the condition cannot achieve the expected effect, and a new shunt channel needs to be established again, which not only increases the cost of surgery but may also be difficult to adjust to the appropriate portal-systemic shunt volume, resulting in treatment failure.

[0004] The portal-system shunt stent graft in the prior art is a straight stent, and the required diameter specification needs to be judged and selected when the stent is implanted in the human body. However, differences in the patient's age, body shape, etc. will result in different sizes of applicable portal-system shunt stent grafts, making it difficult to select the diameter specification of the portal-system shunt stent graft. After the stent is implanted in the human body, problems will arise if the diameter is too large or too small. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the difficulty in selecting the diameter specification of the portal shunt coated stent in the prior art, thereby providing a portal shunt coated stent, a method for manufacturing the portal shunt coated stent and a stent system.

[0006] In order to solve the above technical problems, the present invention provides a portal-body shunt stent graft, comprising:

[0007] The stent body has a covering member covering its outer circumference, and the covering member completely surrounds the circumference of the stent body;

[0008] The area of ​​the stent body covered by the covering includes at least two fixed diameter areas spaced apart and a variable diameter area between two adjacent fixed diameter areas. The yield strength of the covering area corresponding to the variable diameter area is greater than the force applied to the covering when the variable diameter area self-expands.

[0009] Optionally, the stent body includes a bare stent segment and a coated segment, the bare stent segment is arranged at the front end of the coated segment, and the covering is covered on the coated segment.

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

[0011] Optionally, the coating segment is formed by braiding wires in a V-shaped spiral braid;

[0012] And / or, the bare stent segment is formed by braiding wires that are interlaced and connected in a V-shape, and the contact points between the interlaced braided wires are hooked together to form a hanging portion.

[0013] Optionally, positioning marks are provided on the bracket body, and the positioning marks are located at both ends of the covering member.

[0014] Optionally, the positioning mark is fixedly connected to the bracket body.

[0015] Optionally, the covering member includes a first covering segment and a second covering segment connected in sequence, the first covering segment is arranged corresponding to the fixed diameter area, and the second covering segment 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, the second covering sleeve is sleeved outside the first covering sleeve or the second covering sleeve is sleeved 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 zone is provided between the fixed diameter zone and the variable diameter zone, the diameter of the transition diameter zone is smaller than the diameter of the fixed diameter zone, and the diameter of the variable diameter zone is not larger than the diameter of the transition diameter zone.

[0018] Optionally, an inner chamfer or inner rounded corner transition is provided between the transition diameter zone and the fixed diameter zone; an outer chamfer or outer rounded corner transition is provided between the transition diameter zone and the variable diameter zone.

[0019] Optionally, when being delivered to the human body, after the stent body is delivered into place and the outer sheath is withdrawn, the end of the coated segment away from the bare stent segment remains in a restrained state, and the end of the coated segment connected to the bare stent segment is trumpet-shaped.

[0020] The present invention also provides a method for manufacturing a portal-body shunt stent graft, comprising the following steps:

[0021] Prepare the bracket body;

[0022] The covering member is pre-expanded to a preset diameter, so that the diameter of the covering member at a position corresponding to the fixed diameter area is larger than the diameter of the covering member at a position corresponding to the variable diameter area;

[0023] The covering piece is sleeved on the outer periphery of the stent body, so that the diameter of the variable diameter area of ​​the stent body is reduced to a preset diameter under the action of the covering piece.

[0024] The present invention also provides a stent system, comprising a flow-dividing stent and a flow-reducing stent, wherein the flow-reducing stent is suitable for being coaxially inserted into the inner cavity of the flow-dividing stent;

[0025] The shunt stent and the flow-reducing stent are both the portal shunt coated stent described in the present invention.

[0026] The technical solution of the present invention has the following advantages:

[0027] 1. The portal shunt coated stent provided by the present invention comprises a stent body, the outer periphery of which is covered with a coating, and the coating is suitable for plastic deformation under the action of external force; the area of ​​the stent body covered by the coating comprises at least two fixed diameter areas arranged at intervals and a variable diameter area arranged between two adjacent fixed diameter areas. The diameter of the stent body is constrained on the outside by the cylindrical coating, so that the stent remains in a continuous compressed state in the natural state in vitro or after implantation. Before the portal shunt coated stent is implanted into the human body, the stent body and the coating are compressed as a whole. After implantation into the human body, the stent body is self-expanded and unfolded, and the fixed diameter area of ​​the stent body is self-expanded to the maximum size. Due to the limitation of the coating, the variable diameter area of ​​the stent body is self-expanded to the set constrained size. If the portal vein pressure drops less than expected or the shunt channel needs to be enlarged due to other reasons after surgery, the variable diameter area is expanded by a balloon, and the high pressure of the balloon expansion is used to extend the cylindrical coating circumferentially to achieve expansion. The coating is designed to be in a yield state at the minimum diameter. When the covering is expanded, the expansion force is greater than the yield strength of the covering to achieve precise expansion to the size of the balloon, so that the size of the variable diameter area can be accurately controlled within the maximum diameter after expansion. At the same time, because the covering is in a yield state, the covering will not produce elastic retraction after expansion. Under the limiting effect of the covering, the original diameter of the variable diameter area of ​​the stent body is consistent with the maximum diameter, and the variable diameter area can still maintain a good radial support force after expansion, thereby avoiding the loss of the shunt channel due to liver parenchyma compression. The force required for the yield of the cylindrical covering is set to be much greater than the force of the chronic outward radial force of the stent body at the same diameter size, so as to avoid deformation of the covering when the force exerted on the covering by the stent body is greater than the yield strength of the covering, and prevent the covering from being slowly expanded by the stent under the radial supporting force of the stent body, thereby ensuring the stability of the diameter constraint of the covering on the variable diameter zone, so that the stent body in the variable diameter zone can continue to maintain the size stability of the variable diameter zone both before and after expansion, so that the variable diameter zone will neither protrude outward due to the radial force of the stent body, nor be squeezed and collapsed by external human tissue, and there will be no elastic shrinkage after expansion. By setting a variable diameter area on the stent body, the stent diameter selection can be more conservative, and the risk of selecting the wrong stent specification can be effectively avoided. After the portosystemic shunt covered stent is implanted, a balloon with the same diameter as the minimum diameter is used to expand the variable diameter area of ​​the stent body, and then the portal vein pressure is measured to see if it will reach the expected range. If the pressure reduction is not as expected, a balloon with a suitable diameter can be selected to expand the portosystemic shunt covered stent based on the existing pressure value, the expected pressure, and the reduced pressure value. If it is still not satisfied, a balloon with a larger diameter can be selected for further expansion. Similarly, if the shunt channel needs to be enlarged due to recurrent gastrointestinal bleeding or disease progression after surgery, a balloon with a diameter larger than the minimum diameter of the variable diameter area can be selected to expand the variable diameter area based on the expected increase in flow.

[0028] 2. The portal-body shunt coated stent provided by the present invention comprises a bare stent section and a coated section, wherein the bare stent section is arranged at the front end of the coated section, and the covering member is arranged to cover the coated section. By partially setting the stent body as the coated bare stent section, when the portal-body shunt coated stent is implanted in the human body, the bare stent section is arranged toward the front section, and the bare stent section has good flexibility and can well conform to the angle between the shunt channel and the portal vein, thereby avoiding the shunt channel formed inside the stent body from being folded, blocked, or capped.

[0029] 3. The portal-body shunt coated stent provided by the present invention, when delivered to the human body, after the outer tube of the delivery system is withdrawn, the end of the coated section connected to the bare stent section becomes trumpet-shaped. When the trumpet-shaped unfolded coated section is pulled to the junction of the portal vein and the liver parenchyma, an obvious touch can be felt. Thus, the delivery system is stopped when there is an obvious touch, ensuring that the coated section penetrates the portal vein for a short length, avoiding the coating from blocking the portal vein image and affecting the perfusion of the portal vein on the hepatic vein. At the same time, the coating extends out of the liver parenchyma, avoiding the bare stent section from entering the liver parenchyma and entering the shunt channel due to the growth of liver tissue, causing stenosis or occlusion of the shunt channel.

[0030] 4. The present invention provides a stent system, including a shunt stent and a flow reducing stent. The flow reducing stent is suitable for being coaxially inserted into the inner cavity of the shunt stent. The shunt stent and the flow reducing stent are both the portosystemic shunt covered stents described in the present invention. When the liver function of some patients improves after shunting, it is necessary to reduce the shunt volume to achieve better postoperative effects. Or when massive gastrointestinal bleeding is caused by excessive portal vein pressure, it is necessary to quickly and significantly reduce the portal vein pressure to achieve gastrointestinal hemostasis. After the gastrointestinal tract is completely hemostatic and stable, it is necessary to reduce the shunt flow to maintain liver perfusion and reduce the risk of hepatic encephalopathy. There is a lack of effective equipment to reduce the portosystemic shunt volume. At this time, a flow reducing stent is implanted in the inner cavity of the original pre-implanted shunt stent to reduce the portosystemic shunt volume to maintain adequate liver perfusion and reduce blood ammonia levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 Schematic diagram of the structure of the portal shunt stent graft provided in an embodiment of the present invention.

[0033] Figure 2 It is a schematic diagram of the weaving process of the stent body provided in an embodiment of the present invention.

[0034] Figure 3 It is a schematic structural diagram of a stent body of a shunt stent provided in an embodiment of the present invention.

[0035] Figure 4 A schematic diagram of a positioning mark provided in an embodiment of the present invention.

[0036] Figure 5 A schematic diagram of another positioning mark provided in an embodiment of the present invention.

[0037] Figure 6 It is a schematic structural diagram of a bare stent of a flow reducing stent provided in an embodiment of the present invention.

[0038] Figure 7 It is a schematic structural diagram of a stent body of a flow reducing stent provided in an embodiment of the present invention.

[0039] Figure 8 It is a schematic diagram of the structure of the flow reducing stent provided in an embodiment of the present invention.

[0040] Fig. 9 It is a schematic structural diagram of a stent body of another flow reducing stent provided in an embodiment of the present invention.

[0041] Fig.10 It is a schematic structural diagram of another flow reducing stent provided in an embodiment of the present invention after the stent body is connected to a covering member.

[0042] Fig.11 It is a schematic structural diagram of another flow reducing stent provided in an embodiment of the present invention.

[0043] Fig.12 It is a schematic diagram of the structure of the wrapping film provided in an embodiment of the present invention.

[0044] Fig.13 Schematic diagram of the relative position of the unfolded state of the wrapping film and the portal shunt stent graft provided in an embodiment of the present invention.

[0045] Fig.14 It is a schematic structural diagram of the inner tube head provided in an embodiment of the present invention.

[0046] Fig.15 Schematic diagram of the state in which the portal shunt stent graft provided in an embodiment of the present invention is wrapped by a wrapping film.

[0047] Fig.16 It is a schematic diagram of the structure of the conveying system provided in an embodiment of the present invention.

[0048] Fig.17 for Fig.16The partial enlarged view of point A in the middle is a schematic diagram of the structure in which the fixing pin is connected with the bare bracket segment.

[0049] Explanation of the reference numerals in the accompanying drawings: 1. stent body; 101. bare stent segment; 102. coated segment; 1021. fixed diameter area; 1022. variable diameter area; 2. covering; 201. first coating sleeve; 202. second coating sleeve; 3. positioning mark; 4. braided wire; 5. braided pile; 6. inner tube; 7. restraining plate; 8. guide wire cavity; 9. conical head; 10. fixing ring; 11. fixing pin; 12. pull wire. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] In addition, the technical features involved in the different embodiments of the present invention 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 present embodiment shows a portal shunt coated stent provided by the present invention, comprising a stent body 1 and a coating 2 coated on the stent body 1. The stent body 1 may be a metal stent or a biodegradable stent or a medical stent made of other materials, and the coating 2 and a positioning mark 3 are arranged on the stent body 1. The inner cavity of the stent body 1 is a shunt channel, the coating 2 adopts a coating structure, the coating 2 is sleeved outside the stent body 1, and the diameter of the shunt channel can be expanded.

[0056] like Figure 1 As shown, the stent body 1 includes a bare stent segment 101 and a coating segment 102, the coating 2 covers the outer periphery of the stent body 1, the area on the stent body 1 covered by the coating 2 is the coating segment 102, and the bare stent segment 101 is arranged at the front end of the coating segment 102. The coating segment 102 includes at least two fixed diameter areas 1021 arranged at intervals and a variable diameter area 1022 arranged between two adjacent fixed diameter areas 1021, and the diameter of the variable diameter area 1022 is not greater than the diameter of the fixed diameter area 1021. The yield strength of the area of ​​the covering 2 corresponding to the variable diameter zone 1022 is greater than the force applied to the covering 2 when the variable diameter zone 1022 self-expands, so that the variable diameter zone 1022 can be wrapped by the covering 2 and limited to a predetermined diameter when not subject to external force. After the variable diameter zone 1022 is expanded by an external force greater than the yield strength of the area corresponding to the covering 2 and the variable diameter zone 1022, the covering 2 and the area corresponding to the variable diameter zone 1022 undergo plastic deformation and then expand together and limit the diameter of the variable diameter zone 1022 to another predetermined diameter, so as to realize controllable adjustment of the inner diameter of the variable diameter zone 1022 of the stent body 1.

[0057] In this embodiment, Figure 2 As shown, the stent structure as the stent body 1 is woven by braiding wires 4. During the braiding process, braiding piles 5 are set at the corners of the braiding wires 4. The coated section 102 is woven by the braiding wires 4 in a V-shaped spiral; the bare stent section 101 is woven by the braiding wires 4 in a V-shaped staggered direction, and the contact points between the staggered braiding wires 4 are hooked to form a hanging portion. The stent body 1 is formed by a braiding wire 4 being woven and wound between multiple braiding piles 5 through a reciprocating cycle.

[0058] like Figures 3 to 5 As shown, during the weaving of the stent structure as the stent body 1, a positioning mark 3 is fixedly set at the corresponding position to indicate the boundary position of the coating section 102. The positioning mark 3 can be dot-shaped or ring-shaped, or the positioning mark 3 at one end of the coating 2 can be dot-shaped and the positioning mark 3 at the other end can be ring-shaped.

[0059] like Figures 6 to 8As shown, the coated section 102 is divided into a variable diameter area 1022 and a fixed diameter area 1021. An X-ray-proof positioning mark 3 is provided on the edge of the coated section 102. The portal-body shunt coated stent is designed with a controllable diameter. The variable diameter area 1022 can be expanded by a balloon or the like when necessary, and its size can remain stable for a long time after expansion. It can be used as a shunt stent or as a flow-reducing stent. As a shunt stent, the bare stent section 101 provided at the distal end of the stent body 1 has good flexibility and conforms well to the angle between the shunt channel and the portal vein, avoiding folding, occlusion, and capping of the shunt channel. The diameter of the variable diameter area 1022 is smaller than the diameter of the fixed diameter area 1021. The variable diameter area 1022 of the flow-dividing stent can be expanded to a maximum diameter equal to the diameter of the fixed diameter area 1021. When used as a flow-reducing stent, it will be placed inside the flow-dividing stent for use, that is, the flow-dividing stent and the fixed diameter area 1021 of the flow-reducing stent overlap seamlessly. The diameter of the variable diameter area 1022 of the flow-reducing stent is smaller than the variable diameter area 1022 of the flow-dividing stent. The blood flows through the flow-reducing stent but cannot pass through the flow-dividing stent. When the variable diameter area 1022 of the flow-reducing stent expands to the maximum diameter, it is still smaller than the diameter of the fixed diameter areas 1021 at both ends of the coating section 102. In some other embodiments, such as Figures 9 to 11 The schematic diagram of the steps of coating a coating film on a stent body 1 of another portal shunt coated stent is shown. The stent may be entirely composed of coated segments 102 without a bare stent segment 101.

[0060] The portal shunt coated stent can be used as a shunt stent or as a flow-reducing 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 failure of the flow-reducing stent due to excessive expansion size, the maximum diameter that the variable diameter zone 1022 of the stent body 1 can expand to 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, and 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 larger 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, on the stent body 1, an inner chamfer transition may be provided between the transition diameter zone and the fixed diameter zone 1021, or an outer rounded transition may be provided between the transition diameter zone and the variable diameter zone 1022. When the variable diameter zone 1022 of the flow reducing stent is expanded, the maximum expansion is the same as the diameter of the transition diameter zone.

[0061] When preparing the portal shunt coated stent, the stent body 1 is made by a weaving method. The stent body 1 can be a metal stent of equal diameter before coating. In order to facilitate the distinction between the fixed diameter area 1021 and the variable diameter area 1022, in this embodiment, the diameter of the variable diameter area 1022 that has not been coated (i.e., the coating 2) after weaving is slightly smaller than the diameter of the fixed diameter area 1021. The morphology of the portal shunt coated stent is determined by the metal stent. The coating 2 of the cylindrical membrane structure is pre-expanded to a preset diameter by a balloon, so that the diameter of the corresponding position of the coating 2 and the fixed diameter area 1021 is greater than the diameter of the corresponding position of the coating 2 and the variable diameter area 1022. Then the coating 2 is covered and 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 a preset diameter under the action of the coating 2, that is, the diameter of the variable diameter area 1022 is limited by the coating 2 with a large yield strength.

[0062] In this embodiment, the coating 2 includes a first coating sleeve 201 and a second coating sleeve 202, the first coating sleeve 201 is sleeved outside the stent body 1, the second coating sleeve 202 is sleeved outside the first coating sleeve 201 or between the first coating sleeve 201 and the stent body 1, and the second coating sleeve 202 is arranged corresponding to the variable diameter area 1022. Among them, the first coating sleeve 201 is a conventional coating, which is used to wrap the stent body 1 to form a flow passage, and the yield strength of the second coating sleeve 202 is greater than the force applied to the coating 2 when the variable diameter area 1022 self-expands. In some other embodiments, the coating 2 can also be a single-layer structure, including a first coating segment and a second coating segment connected in sequence, the first coating segment is arranged corresponding to the fixed diameter area 1021, and the second coating segment is arranged corresponding to the variable diameter area 1022. The first coating segment is a conventional coating, and the yield strength of the second coating segment is greater than the force exerted on the coating member 2 when the variable diameter region 1022 self-expands.

[0063] like Fig.12 and 13 As shown, before the portal shunt stent graft is delivered into the human body, the portal shunt stent graft needs to be assembled with the delivery system. Most of the coating section 102 of the stent body 1 is sized by the constraint sheet 7, and the portal shunt stent graft fixed by the constraint sheet 7 is compatible with the outer sheath of the TIPS puncture system of 10F specification (the specifications in this embodiment can be multiple, and this specification is only used for demonstration and explanation). When the stent needs to be released, the constraint sheet 7 is released by pulling the pull wire 12 backward, so that the constraint sheet 7 is automatically unfolded, thereby realizing the unfolding and release of the portal shunt stent graft.

[0064] like Fig.14As shown in FIG. 17 , the delivery system of the portal shunt stent graft includes an inner tube 6, the inner cavity of the inner tube 6 is a guidewire cavity 8, and the guidewire cavity 8 is suitable for the guidewire to pass through. In order to facilitate the advancement inside the human body, the front end of the inner tube 6 is provided with a conical head 9, and the outer wall of the inner tube 6 is provided with a fixing ring 10 near the front end. A fixing pin 11 is fixedly connected to the fixing ring 10, and the fixing pin 11 extends toward the front end of the inner tube 6. The fixing pin 11 is suitable for inserting into the hanging part of the bare stent segment 101 to drive the portal shunt stent graft to move, or to position the stent body 1 when releasing the portal shunt stent graft. The bare stent segment 101 is hung on the core shaft of the delivery system, so that the product has good transportability during the delivery process. When the delivery system is withdrawn, the inner tube 6 with the fixing pin 11 is out of contact with the bare stent segment 101, so as to separate the delivery system from the portal shunt stent graft.

[0065] Specifically, during the TIPS operation, the jugular vein is first punctured, and a 10F outer sheath is inserted from the jugular vein into the retrohepatic inferior vena cava, a loading catheter is inserted into the outer sheath into the opening of the right hepatic vein, and the exit direction of the loading catheter is adjusted, and then the puncture catheter with a puncture needle is guided into the loading catheter, and the liver is punctured with the puncture needle to enter the left branch of the portal vein or the right branch of the portal vein, and the puncture catheter is exchanged with a guide wire, and the guide wire is adjusted to extend to the splenic vein or the superior mesenteric vein of the portal vein trunk, and then the outer sheath and the loading catheter are pushed into the portal vein trunk along the guide wire. The assembled portal-body shunt covered stent and the inner tube 6 are inserted from the inner cavity of the loading tube along the guide wire, and the bare stent segment 101 of the stent body 1 at the front end is first entered into the portal vein trunk. After the portal-systemic shunt coated stent is delivered to the right position in the human body, the stent can be pulled back to locate it by touch, that is, the outer sheath and loading catheter of the delivery system can be withdrawn to semi-release the stent. At this time, the stent body 1 gradually expands radially from the bare stent segment 101 under the action of self-expansion force. Since the remaining part of the coated segment 102 continues to be kept in a compressed state by the constraint sheet 7, the middle and rear sections of the coated segment 102 can still remain in a constrained state, and the end of the coated segment 102 adjacent to the bare stent segment 101 is unfolded into a trumpet shape, so that the portal-systemic shunt coated stent can still be pulled back by the delivery system to determine the release position by touch (gently withdraw the outer sheath and loading catheter, and you will feel an obvious touch when the unfolded coated segment 102 is pulled trumpet-shaped to the junction of the portal vein and the liver parenchyma). When there is an obvious touch, stop pulling the delivery system back to ensure that the coated segment 102 penetrates into the portal vein for a short length to avoid the coated segment 102 blocking the portal vein image and affecting the perfusion of the hepatic vein. At the same time, it is ensured that the coated section 102 extends out of the liver parenchyma, so as to avoid narrowing or occlusion of the shunt channel caused by liver tissue growth after the bare stent section 101 enters the liver parenchyma, thereby solving the problem of inaccurate positioning of the liver movement component markers during the portosystemic shunt operation due to the inability to accurately determine the junction between the portal vein and the liver parenchyma and the inaccurate positioning of the liver movement component markers during the breathing process. The delivery system fixes the bare stent section 101, making the delivery and release process easier and more stable, avoiding the accumulation of the stents caused by insufficient axial support of the stent itself during the delivery and release of the portal-body shunt coated stent, resulting in excessive or difficult delivery and release, and also avoiding the inaccurate release position caused by the backward movement of the stent during the release process. After the end of the portal-body shunt coated stent is positioned, the loading catheter, the outer sheath tube and the inner tube 6 are withdrawn in turn, and the pull line 12 on the constraint sheet 7 is pulled to automatically unfold the constraint sheet 7, thereby realizing the deployment of the portal-body shunt coated stent. Finally, the variable diameter area 1022 of the stent body 1 is expanded by a balloon, so that the inner diameter of the variable diameter area 1022 is expanded to a predetermined diameter. Thereby, a blood flow channel of portal vein-portasystemic shunt covered stent-hepatic vein is established, so that part of the blood flow from the portal vein can directly enter the heart through the hepatic vein through the portosystemic shunt covered stent without being metabolized by the liver, thereby reducing the portal vein pressure.When it is necessary to increase the inner diameter of the portal shunt stent graft, the variable diameter area 1022 of the stent body 1 is expanded to another larger predetermined diameter by an inflation balloon with a larger diameter; when it is necessary to reduce the inner diameter of the portal shunt stent graft, another portal shunt stent graft is inserted inside the stent body 1 to ensure that the fixed diameter area 1021 of the stent body 1 of the later inserted portal shunt stent graft is in contact with the fixed diameter section of the stent body 1 of the previous portal shunt stent graft, and the variable diameter area 1022 of the stent body 1 in the later inserted portal shunt stent graft is expanded to another smaller predetermined diameter by another balloon with a smaller outer diameter.

[0066] The portosystemic shunt covered stent provided in this embodiment adopts multiple diameter specifications, and adds a variety of smaller diameter specifications compared to existing marketed products. In addition, the use of diameter expandable technology makes the selection of covered stents simple and feasible during intrahepatic portosystemic shunt surgery via jugular vein puncture. The portosystemic shunt covered stent can be used as a flow-reducing stent placed inside the shunt stent, so that when facing excessive shunt during or after intrahepatic portosystemic shunt surgery, poor liver perfusion, and severe hepatic encephalopathy, a flow-reducing stent can be implanted in the original implanted portosystemic shunt covered stent to reduce the portosystemic shunt volume to maintain sufficient liver perfusion and reduce blood ammonia. Specifically, for the existing marketed portosystemic shunt covered stents, for Asians with an overall excessive shunt and for patients with partially salvageable liver, there is a problem of excessive shunt. Compared with existing marketed products, a variety of smaller diameter specifications are added, and a variety of diameter models of portosystemic shunt covered stents are designed as shunt stents. During the operation, the appropriate diameter portosystemic shunt covered stent can be selected according to portal vein pressure, patient body shape, and different stages of the disease.

[0067] In view of the problem that although the stent diameter can be selected according to the portal vein pressure, body shape, and disease stage in clinical practice, it is still impossible to accurately select the appropriate shunt stent specifications, a variable diameter area 1022 with a local diameter expandable is set on the coated section 102 of the stent body 1 in the portal shunt coated stent, so that the minimum diameter of the stent can be selected more safely. When the portal shunt coated stent is implanted in the human body, if the portal vein pressure is still too high after the shunt, the variable diameter area 1022 is expanded by an expansion balloon of a suitable diameter, and the channel is expanded to the target diameter by the balloon diameter specification and expansion pressure. This avoids the problem that the conventional portal shunt coated stent diameter selection is too large, which easily leads to excessive shunt, and the selection is too small, which leads to insufficient shunt. Specifically, the stent body 1 is first made into an equal diameter tube, with a flexible bare stent section 101 at the front end, a coated section 102 in the middle, and a coated section 102 set continuously with the middle at the end or another bare stent section 101. The required coated sleeve is made by the composite film process, and then the sleeve composed of the coating 2 with the same minimum diameter as the intended minimum diameter after circumferential stretching is sleeved on the compressed coated section 102, and the coating 2 is connected to the stent body 1 by the support force of the stent body 1 itself or by hot melting, bonding, suturing, etc. Alternatively, a sleeve of the coating 2 smaller than the preset minimum diameter of the stent can be sleeved on the stent body 1, and the stent body 1 is expanded by a balloon so that the coating 2 is stretched circumferentially to a yield state, and the yield strength of the coating 2 is controlled to be greater than the chronic outward radial support force of the stent at this diameter size. Among them, the yield state is also called the yield stage. In material mechanics, the yield stage refers to the material being subjected to external force. After the stress exceeds a certain value, the material will undergo permanent deformation, and this process is irreversible. In this way, the sleeve composed of the coating 2 can overcome the chronic outward radial support force of the stent body 1, so that the variable diameter area 1022 is maintained in the set size state for a long time. Similarly, after the portal-body shunt stent graft is implanted in the human body, the variable diameter area 1022 is expanded, which can also overcome the radial support force of the stent body 1, so that the variable diameter area 1022 is maintained at the expanded size. At the same time, because the variable diameter area 1022 can maintain the diameter stability of the area for a long time, the problem of excessive shunt caused by the change of the shunt channel diameter after conventional portal-body shunt stent graft surgery is effectively avoided.

[0068] Conventional portal shunt coated stents are straight stents. If the stent is expanded directly to the designed diameter of the stent, the force between the stent and the channel will be relatively soft. Before the stent and the channel are stably combined, it is easy to cause the stent to shift due to factors such as blood flow and improper operation, resulting in treatment failure and easy stenosis of the channel. The current common clinical solution is to control the stent expansion to be about 2mm thinner than the stent diameter. Although this method solves the problem of stent displacement. But it brings a new problem. Under the action of the chronic outward force of the stent, in most cases, as the shunt channel expands, the shunt channel will expand to a diameter close to the designed diameter of the stent under the action of the stent, and the portal vein shunt is too large, resulting in too much blood that is not processed by the liver, resulting in excessive blood ammonia content in the blood causing hepatic encephalopathy. In this embodiment, the diameter of the coated section 102 is constrained on the outside of the stent body 1 by the sleeve of the coating 2, so that the variable diameter area 1022 of the stent body 1 remains in a continuous compressed state in the natural state in vitro or after implantation. If the portal vein pressure drops less than expected after implantation or the shunt channel needs to be enlarged for other reasons after surgery, the variable diameter area 1022 is expanded by a balloon, and the high pressure of the balloon expansion is used to extend the covering 2 circumferentially to achieve expansion. Specifically, by designing the covering 2 to be in a yielding state at the minimum diameter, when the covering 2 is expanded, the expansion force is greater than the yield strength of the covering 2, and accurate expansion to the size of the balloon can be achieved. Thereby, the size of the variable diameter area 1022 of the stent body 1 can be accurately controlled within the maximum diameter, and at the same time, because the covering 2 is in a yielding state, the sleeve will not elastically retract after expansion. The original diameter of the fixed diameter area 1021 of the stent body 1 is consistent with the maximum diameter. After the variable diameter area 1022 is expanded, it will still maintain a good radial support force, thereby avoiding the loss of the shunt channel due to liver parenchyma compression. The yield force value of the coating 2 is set to be much larger than the chronic outward radial force value of the stent body 1 at the same diameter size, so that the variable diameter zone 1022 of the coating segment 102 can continue to maintain the size stability of the variable diameter zone 1022 before and after expansion, and will neither protrude outward due to the radial force of the stent body 1 nor be squeezed and collapsed by the liver parenchyma. At the same time, there will be no elastic retraction after expansion.

[0069] During the operation, the diameter of the portosystemic shunt covered stent can be selected more conservatively, which can effectively avoid the risk of choosing the wrong stent specification. After the portosystemic shunt covered stent is implanted, a balloon with the same diameter as the minimum diameter can be used to dilate the channel, and then measure whether the portal vein pressure is within the expected range. If the pressure reduction is less than expected, a balloon with a suitable diameter can be selected to dilate the variable diameter area 1022 based on the current pressure value, the expected pressure and the reduced pressure value. If it is still not satisfied, a balloon with a larger diameter can be selected for further dilation.

[0070] Similarly, if the shunt channel needs to be enlarged due to recurrence of gastrointestinal bleeding or progression of the disease after surgery, a balloon with a diameter larger than the current minimum diameter specification of the variable diameter area 1022 can be selected to expand the variable diameter area 1022 according to the expected increase in flow.

[0071] When the portal-body shunt covered stent is used as a flow-reducing stent, it is also designed to have a controllable diameter to avoid the risk of excessive flow reduction and re-inducing ascites, hepatic encephalopathy, etc., to facilitate the selection of the flow-reducing stent diameter and reduce the risk of excessive flow reduction. In some other embodiments, the stent body 1 of the flow-reducing stent may not be provided with a bare stent segment 101.

[0072] The coated section 102 of the portal-body shunt stent graft provided in this embodiment is partially a variable diameter area 1022, which requires that the diameter can be expanded and can maintain long-term stability after expansion, reducing the risk of stent diameter selection, and the stent diameter can be relatively conservatively selected to reduce the risk of excessive shunt. The flow-reducing stent is used to reduce the flow of the shunt channel during surgery to maintain liver perfusion when the shunt is too large, or when the shunt channel needs to be reduced for severe hepatic encephalopathy after surgery or when the liver function is partially restored and the shunt channel is expected to be reduced, solving the problem of the lack of remedial measures for excessive shunt or severe hepatic encephalopathy.

[0073] The diameter specifications of existing portosystemic shunt covered stents are too large. The existing stents are imported from abroad and are designed for European and American body types. The smallest diameter specification can only meet the needs of some Chinese people. Even if the smallest diameter specification is selected, the other part will still suffer from the side effects of excessive shunt. In the current portosystemic shunt treatment of portal hypertension, there is a lack of effective remedial measures to reduce the portosystemic shunt volume when faced with poor liver perfusion and severe hepatic encephalopathy caused by excessive shunt. This embodiment can meet the small diameter stent specifications required by Asians by setting a variety of different diameter specifications. The minimum diameter of the TIPS stent currently on the market is 8mm. This solution sets diameter specifications of 5-7mm, 6-8mm, 7-9mm, and 8-10mm. A rich variety of diameter specifications can better meet clinical needs and reduce the incidence of hepatic encephalopathy.

[0074] The maximum coating length of the existing portal-system shunt stent graft is only 8cm. For some patients, due to the long TIPS channel, two to three stents need to be implanted to achieve the isolation of the shunt channel by the coating. It increases the burden on patients and may also bring the risk of channel stenosis due to stent overlap. The length of the portal-system shunt stent graft provided in this embodiment is set in a variety of specifications, so that patients can use one portal-system shunt stent graft to establish a shunt channel as much as possible, reducing surgical costs and fatigue risks caused by stent overlap. At the same time, when the channel is too long and the puncture entrance is not in the liver parenchyma, if a second portal-system shunt stent graft is added, blood may flow into the abdominal cavity from the inferior vena cava puncture port between the two portal-system shunt stent grafts. At the same time, it can also avoid the risk of the guide wire being brought out when the delivery system is evacuated after the first stent is placed, because when the guide wire passes through the complete channel that has not been supported by the stent, due to the elastic retraction of the liver tissue, there is a problem of difficulty in re-sending the guide wire into the punctured channel.

[0075] The concept of the existing portosystemic shunt covered stent design is to reduce the patient's pain and the risk of gastrointestinal bleeding through TIPS treatment in patients with severe portal hypertension. After decades of development, treatment has been pushed forward. After the discovery of portal hypertension caused by impaired liver function, portosystemic shunt surgery will no longer be performed until the end stage. Instead, early treatment can better delay the degree of liver function decline, reduce the risk of gastrointestinal bleeding, and solve the problem of ascites. At this stage, a thinner shunt can reduce the risk of gastrointestinal bleeding and relieve ascites; at the same time, a thin shunt can reduce the risk of hepatic encephalopathy; maintaining good liver perfusion is conducive to the recovery or stabilization of liver function and avoid liver failure.

[0076] Example 2

[0077] This embodiment provides a stent system, including a shunt stent and a flow reducing stent. The flow reducing stent is suitable for being coaxially inserted into the inner cavity of the shunt stent. The shunt stent and the flow reducing stent are both the portal shunt coated stent described in Example 1.

[0078] When the portosystemic shunt covered stent is used as a flow-reducing stent, it is also designed to have a controllable diameter to avoid the risk of excessive flow reduction causing ascites, hepatic encephalopathy, etc., to facilitate the selection of the flow-reducing stent diameter and reduce the risk of excessive flow reduction. In some other embodiments, the stent of the flow-reducing stent is not provided with a bare stent segment 101.

[0079] The coated section 102 of the flow-reducing stent has a large diameter at both ends and a thin middle part. The variable diameter area 1022 is located in the middle. The variable diameter area 1022 can be expanded again when necessary. The variable diameter area 1022 of the flow-reducing stent is still smaller than the diameter of the two ends of the coating when expanded to the maximum. The diameter specifications of the two ends of the coating are designed to match the maximum diameter of the shunt stent. The flow-reducing diameter can be anchored in the shunt stent, and the channel diameter can be reduced by reducing the diameter of the variable diameter area 1022. If the new shunt flow is too low during or after surgery, the variable diameter area 1022 of the flow-reducing stent can be expanded.

[0080] At the same time, when liver function partially improves after implantation of a shunt stent, there is a need to reduce the shunt volume to achieve a better prognosis for patients; or when excessive portal vein pressure causes massive gastrointestinal bleeding, it is necessary to quickly and significantly reduce portal vein pressure to stop gastrointestinal bleeding. After the gastrointestinal bleeding is completely stopped and stabilized, the shunt flow needs to be reduced to maintain liver perfusion, but there is a lack of effective equipment to reduce the portosystemic shunt volume. The above effect can be achieved by implanting another portosystemic shunt covered stent as a flow-reducing stent in the shunt stent.

[0081] For situations where it is necessary to reduce the shunt channel during or after surgery, the flow-reducing stent is designed to be waist-drum-shaped, and can be provided with a bare stent segment 101 or a fully coated structure. In the same way, a coated sleeve smaller than the intended minimum diameter is sleeved on the small waist segment of the compressed flow-reducing coated stent, and the sleeve is connected to the stent coating through the coating stent's own support force or by bonding, suturing, etc. By expanding the inside of the variable diameter area 1022 of the stent body 1, the coating 2 is radially stretched and extended to a yield state, and the yield strength of the coating 2 is greater than the chronic outward radial support force of the stent at this diameter size. In this way, the coating 2 can overcome the radial support force of the stent, so that the variable diameter area 1022 remains in the set size state. After implantation, the variable diameter area 1022 is expanded, which can also overcome the radial support force of the stent body 1, so that the variable diameter area 1022 remains in the expanded size.

[0082] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A portal shunt stent graft, characterized in that: include A support body (1) having an outer circumference covered with a covering member (2), wherein the covering member (2) completely surrounds the circumference of the support body (1); The area of ​​the stent body (1) covered by the covering (2) comprises at least two fixed diameter areas (1021) arranged at intervals and a variable diameter area (1022) arranged between two adjacent fixed diameter areas (1021), and the yield strength of the area of ​​the covering (2) corresponding to the variable diameter area (1022) is greater than the force applied to the covering (2) by the variable diameter area (1022) when self-expanding.

2. The portal-body shunt stent graft according to claim 1, characterized in that: The stent body (1) comprises a bare stent section (101) and a coated section (102); the bare stent section (101) is arranged at the front end of the coated section (102); and the covering member (2) is arranged to cover the coated section (102); Alternatively, the covering member (2) completely covers the stent body (1) in the axial direction.

3. The portal-body shunt stent graft according to claim 2, characterized in that: The coating section (102) is formed by braiding the braided wire (4) in a V-shaped spiral. And / or, the bare stent segment (101) is formed by braiding wires (4) that are interlaced and connected in a V-shape, and the contact points between the interlaced and connected braided wires (4) are interlaced to form a hanging portion.

4. The portal-body shunt stent graft according to any one of claims 1 to 3, characterized in that: Positioning marks (3) are provided on the bracket body (1), and the positioning marks (3) are located at two ends of the covering member (2).

5. The portal-to-portal shunt stent graft according to any one of claims 1 to 3, characterized in that: The covering member (2) comprises a first covering segment and a second covering segment connected in sequence, the first covering segment being arranged corresponding to the fixed diameter area (1021), and the second covering segment being arranged corresponding to the variable diameter area (1022); Alternatively, the coating member (2) includes a first coating sleeve (201) and a second coating sleeve (202), wherein the first coating sleeve (201) is sleeved outside the stent body (1), and the second coating sleeve (202) is sleeved outside the first coating sleeve (201) or the second coating sleeve (202) is sleeved between the first coating sleeve (201) and the stent body (1), and the second coating sleeve (202) is arranged corresponding to the variable diameter zone (1022).

6. The portal-body shunt stent graft according to any one of claims 1 to 3, characterized in that: A transition diameter zone is provided between the fixed diameter zone (1021) and the variable diameter zone (1022), 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 larger than the diameter of the transition diameter zone.

7. The portal-body shunt stent graft according to claim 6, characterized in that: An inner chamfer or inner rounded corner transition is provided between the transition diameter zone and the fixed diameter zone (1021); an outer chamfer or outer rounded corner transition is provided between the transition diameter zone and the variable diameter zone (1022).

8. The portal-body shunt stent graft according to claim 2 or 3, characterized in that: When the portal-body shunt coated stent is released in the body, after the outer sheath is withdrawn at the preset release position, the end of the coated section (102) away from the bare stent section (101) remains in a restrained state, and the end of the coated section (102) connected to the bare stent section (101) is trumpet-shaped.

9. A method for manufacturing the portal shunt stent graft according to any one of claims 1 to 8, characterized in that: The following steps are involved: Preparing a support body (1); The covering member (2) is pre-expanded to a preset diameter, so that the diameter of the covering member (2) at a position corresponding to the fixed diameter region (1021) is greater than the diameter of the covering member (2) at a position corresponding to the variable diameter region (1022); The covering member (2) is sleeved on the outer circumference of the stent body (1) in a contracted state, so that the diameter of the variable diameter area (1022) of the stent body (1) expands to a preset diameter under the action of the covering member (2).

10. A support system, characterized in that: It comprises a flow-dividing stent and a flow-reducing stent, wherein the flow-reducing stent is suitable for being coaxially arranged in the inner cavity of the flow-dividing stent; The shunt stent and the flow reducing stent are both portal shunt coated stents as described in any one of claims 1 to 8.

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