Tips covered stent

Abstract

A TIPS covered stent, comprising a covered segment (1), an uncovered segment (2) and a binding membrane (3), wherein the covered segment (1) comprises a first frame (11) and a covering membrane (12); the binding membrane (3) covers at least a portion of the covering membrane (12) on the outside of the covering membrane; the binding membrane (3) binds the covered segment (1) to enable the covered segment (1) to have a first radial dimension, and can expand in radial dimension under the action of an external force to enable the covered segment (1) to have a second radial dimension; the binding membrane (3) comprises a main body portion (31), a first end and a second end; and a connecting portion (32) is provided at the first end and / or the second end, and the dimension of the connecting portion (32) in the circumferential direction of the covered segment (1) at the end away from the main body portion (31) is smaller than the dimension thereof in the circumferential direction of the covered segment at the end close to the main body portion (31). The arrangement of the binding membrane of the TIPS covered stent reduces the resistance during the insertion or withdrawal of a sheath, also reduces the probability of crimping of the binding membrane, and during the variable-diameter expansion of the TIPS covered stent, prevents the connecting portion at the first end and the second end of the binding membrane from being broken, separated from the covering membrane, etc., at the connection of the connecting portion with the covering membrane.

Description

TIPS covered stent

[0001] Cross-references

[0002] The present invention is based on Chinese patent applications with application numbers "202311269998.0" and "202322655303.4" and application date of September 27, 2023, and claims the priority of the above-mentioned Chinese patent applications. The entire contents of the above-mentioned Chinese patent applications are hereby incorporated into the present invention by introduction. Technical Field

[0003] The present invention belongs to the technical field of medical devices, and more specifically, relates to a TIPS coated stent. Background Art

[0004] Globally, cirrhosis is the fourth leading cause of death (non-communicable diseases) after cancer, cardiovascular disease, and chronic lung disease. Cirrhosis alters the liver's structural structure, causing blood vessels within the liver to become compressed and narrowed. Blood in the portal vein flows through the liver and returns to the heart via the hepatic vein. Therefore, when blood flow is impaired, portal vein pressure increases, leading to portal hypertension in cirrhosis. Portal hypertension in cirrhosis can lead to a variety of complications, including esophageal and gastric variceal bleeding, intractable ascites, hepatic encephalopathy, and hepatorenal syndrome.

[0005] With the development of minimally invasive surgery, the transjugular intrahepatic portosystemic shunt (TIPS) was invented and used for portal hypertension in cirrhosis. In TIPS, the operator uses specialized minimally invasive instruments, guided by X-ray fluoroscopy, through the jugular vein to create an artificial intrahepatic shunt channel between the hepatic vein and the main branch of the portal vein. A metal stent is used to maintain permanent patency, thereby reducing portal hypertension, controlling and preventing bleeding from esophageal and gastric varicose veins, and promoting ascites absorption.

[0006] The TIPS covered stent usually includes a bare segment and a covered segment with a membrane. The bare segment is used to position in the portal vein to ensure that the blood perfusion of the portal vein to other branches is not affected. The covered segment is used to position in the liver and hepatic vein to effectively prevent bile erosion. In the TIPS procedure, a key step is the selection of the stent diameter. If the stent diameter is too small, the shunt volume of the shunt channel between the hepatic vein and the portal vein is insufficient, and the portal vein pressure is not relieved enough, which may still cause the esophageal and gastric veins to rupture and bleed again. If the stent diameter is too large, the shunt volume of the shunt channel between the hepatic vein and the portal vein is too large, because the shunted portal vein blood does not undergo detoxification by the liver and re-enters the blood circulation, which leads to an increase in blood ammonia concentration. Excessive ammonia entering the brain will cause hepatic encephalopathy (HE). Severe hepatic encephalopathy can cause coma or even death in patients.

[0007] In order to solve the problem of stent diameter selection, patent document US20010053929A1 proposes a variable diameter covered stent. Specifically, a layer of restraining membrane is inserted on the outside of the covered segment. The restraining membrane and the covered segment are connected together. The restraining membrane has a certain restraining force on the covered segment of the stent. In the initial stage, the restraining membrane can limit the diameter of the covered segment of the covered stent. Then, the restraining membrane is expanded by external force to cause plastic deformation of the restraining membrane. The covered segment of the covered stent expands with the expansion of the restraining membrane, which effectively solves the problem of stent diameter selection. In this covered stent, the restraining membrane must be connected to the covered segment at least at both ends, and the two end faces of the restraining membrane are straight. There are many problems with this covered stent. For example, when the coated stent is pressed and gripped into the sheath, the gripping force will increase, and the gripping difficulty will increase; under the premise that the inner cavity space of the sheath of the delivery device is limited, a circle of restraining membrane (even including connecting medium) is directly added to the outside of the coating, which further squeezes the space in the sheath, increases the difficulty of sheathing, and the end of the restraining membrane is prone to curling when sheathing; because the restraining membrane is connected to the coating as a whole, it needs to be coated with adhesive, positioned, and baked at high temperature, and the manufacturing process is complicated and time-consuming; when expanding under the action of external force, because the restraining membrane and the coating are connected as a whole, the expansion of the restraining membrane is constrained by the connection, and it is difficult to expand freely and plastically deform, thereby affecting the diameter change effect of the coating section, and when the restraining membrane expands, the connection between the restraining membrane and the coating is subjected to greater force, and it is easy for the restraining membrane to break at the connection and the restraining membrane and the coating to separate.

[0008] Summary of the Invention

[0009] The purpose of the embodiments of the present invention is to provide a TIPS covered stent to solve one or more of the above-mentioned technical problems.

[0010] To achieve the above-mentioned object, the present invention provides a TIPS covered stent, comprising a covered segment at the proximal end, a bare segment at the distal end, and a restraining membrane, wherein the covered segment comprises a first frame and a covered membrane;

[0011] The distal end of the first frame is connected to the proximal end of the bare segment, the covering film at least covers and is fixed to the outside of the first frame, and the binding film covers at least a portion of the covering film on the outside of the covering film;

[0012] The membrane segment has a first radial dimension and a second radial dimension, wherein the second radial dimension is larger than the first radial dimension. The restraining membrane is configured to restrain the membrane segment so that the membrane segment is in the first radial dimension, and can expand the radial dimension under the action of an external force so that the membrane segment is restrained in the second radial dimension.

[0013] The restraining membrane includes a main body, a first end located at the proximal end of the main body, and a second end located at the distal end of the main body, the first end and / or the second end is provided with a connecting portion for fixedly connecting to the covering membrane, and the dimension of the end of the connecting portion away from the main body in the circumferential direction of the covering membrane segment is smaller than the dimension of the end close to the main body in the circumferential direction of the covering membrane segment.

[0014] In one embodiment, the greater the axial distance between the connecting portion and the main body portion, the smaller the size of the connecting portion in the circumferential direction of the coating segment.

[0015] In one embodiment, in the axial direction of the covering segment, the length of the restraining film is smaller than the length of the covering film, and the restraining film is located in the middle of the covering segment.

[0016] In one embodiment, the distance from the first end of the constraining membrane to the proximal end of the covering membrane is 5-10 mm.

[0017] In one embodiment, the distance from the second end of the constraining membrane to the distal end of the covering membrane is 5-10 mm.

[0018] In one embodiment, the distance from the first end of the tethering membrane to the proximal end of the covering membrane is not equal to the distance from the second end of the tethering membrane to the distal end of the covering membrane.

[0019] In one embodiment, the connecting portion includes a top area and a connecting area, wherein the top area is away from the main body and is used to be fixedly connected to the covering film, and the connecting area is close to the main body and connected to another connecting portion.

[0020] In one embodiment, the first frame includes a plurality of first structural units, at least some of which are connected in sequence;

[0021] For the connecting portion provided at the first end of the tethering membrane, a portion of the connecting portion away from the main body portion is located on the distal side of the first structural unit that is axially closest to the first structural unit;

[0022] With respect to the connecting portion disposed at the second end of the tethering membrane, a portion of the connecting portion away from the main body portion is located proximal to the first structural unit that is axially closest.

[0023] In one embodiment, a plurality of the first structural units are sequentially connected to form a protrusion toward the distal end and a depression toward the proximal end;

[0024] The connecting portion includes a top area and a connecting area. The portion of the connecting portion away from the main body is defined as the top area, and the top area is used to be fixedly connected to the covering film. The connecting portion close to the main body is defined as the connecting area, and the connecting area is connected to another connecting portion.

[0025] For the connecting portion provided at the first end of the tie film, the connecting region is provided on the distal side of the protrusion near the recess;

[0026] Regarding the connecting portion provided at the second end of the tie film, the connecting region is provided on the proximal side of the recess near the protrusion.

[0027] In one embodiment, the connection region of the connection portion is directly connected to the connection region of another connection portion.

[0028] In one embodiment, the connection region of the connection portion is connected to the connection region of another connection portion through the main body portion.

[0029] In one embodiment, a contour edge of the connecting portion between the top region and the connecting region is parallel to a contour edge between the protrusion and the recess of the corresponding first structural unit.

[0030] In one embodiment, for the connecting portion provided at the first end of the restraining film, the depression corresponding to the top region and the protrusion corresponding to the connecting region are spaced apart by a plurality of the first structural units.

[0031] For the connecting portion provided at the second end of the restraining membrane, the protrusion corresponding to the top area and the depression corresponding to the connecting area are spaced apart by a plurality of the first structural units.

[0032] In one embodiment, for the connecting portion provided at the first end of the restraining film, the depression corresponding to the top region is adjacent to the protrusion corresponding to the connecting region;

[0033] For the connecting portion provided at the second end of the restraining film, the protrusion corresponding to the top area is adjacent to the recess corresponding to the connecting area.

[0034] In one embodiment, for all the connection portions provided at the first end of the tie film, all the connection regions are directly connected in sequence;

[0035] For all the connection portions provided at the second end of the tie film, all the connection areas are directly connected in sequence.

[0036] In one embodiment, a plurality of the first structural units are distributed spirally along the axial direction of the coating segment.

[0037] In one embodiment, the first frame includes a plurality of structural components, and the plurality of structural components are arranged at intervals along the axial direction of the coating segment, and each of the structural components includes a plurality of first structural units distributed circumferentially along the coating segment; adjacent structural components are connected through the coating, or adjacent structural components are connected through connecting parts.

[0038] In one embodiment, when a plurality of the first structural units are spirally distributed along the axial direction of the coating segment, the connecting portions are spirally arranged in the same direction;

[0039] When the first structural units in the structural assembly are distributed circumferentially along the coating segment and are located in a same plane perpendicular to the axial direction, the connecting portions are arranged circumferentially and are located in a same plane perpendicular to the axial direction.

[0040] In one embodiment, the main body has a corrugated structure, and the corrugated structure is used to prevent the main body from being axially shortened when the coating segment turns from the first radial dimension to the second radial dimension.

[0041] In one embodiment, the bare segment includes a second frame, and a radial dimension of at least a portion of the second frame is larger than a radial dimension of the first frame.

[0042] The TIPS coated stent provided by an embodiment of the present invention includes a coated segment at the proximal end, a bare segment at the distal end, and a restraining membrane, the coated segment includes a first frame and a coating, the distal end of the first frame is connected to the proximal end of the bare segment, the coating at least covers and is fixed to the outside of the first frame, and the restraining membrane covers at least part of the coating on the outside of the coating; the coated segment has a first radial dimension and a second radial dimension, the second radial dimension is larger than the first radial dimension, the restraining membrane is configured to restrain the coated segment so that the coated segment is in the first radial dimension, and can expand the radial dimension under the action of external force so that the coated segment is restrained in the second radial dimension; the restraining membrane includes a main body, a first end located at the proximal end of the main body, and a second end located at the distal end of the main body, the first end and / or the second end is provided with a connecting portion for fixedly connecting to the coating, the size of the end of the connecting portion away from the main body in the circumferential direction of the coating segment is smaller than the size of the end of the connecting portion close to the main body in the circumferential direction of the coating segment. In this way, the fixation method between the binding membrane and the covering is simpler and faster; the force required when pressing and gripping the covering section is smaller, and it is easier to press and grip; when the TIPS covered stent is inserted into the sheath, under the condition of a certain space in the inner cavity of the sheath, the resistance of the part of the TIPS covered stent provided with the binding membrane when pressing into the sheath or the sheath is withdrawn is reduced, and the probability of curling of the binding membrane is also reduced; because the connecting part of the binding membrane is subjected to less force at the connection with the covering, when the TIPS covered stent changes diameter and expands, the connection part of the binding membrane is avoided from breaking at the connection with the covering, and the binding membrane is avoided from separating from the covering. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] FIG1 is a schematic structural diagram of a TIPS stent graft provided by one embodiment of the present invention;

[0045] FIG2 is a schematic structural diagram of a TIPS covered stent provided by one embodiment of the present invention after the restraining membrane is deployed;

[0046] FIG3 is a partial schematic diagram of the connection portion of the tie film shown in FIG2 being connected to the covering film segment;

[0047] FIG4 is a schematic structural diagram of a TIPS covered stent provided by another embodiment of the present invention after the restraining membrane is deployed;

[0048] FIG5 is a partial schematic diagram of the connection portion of the tie film shown in FIG4 being connected to the covering film segment;

[0049] FIG6 is a schematic structural diagram of a TIPS covered stent provided by another embodiment of the present invention after the restraining membrane is deployed;

[0050] FIG7 is a partial schematic diagram of the connection portion of the tie film shown in FIG6 being connected to the covering film segment;

[0051] FIG8 is a schematic structural diagram of a TIPS stent graft provided with the restraining membrane shown in FIG6 ;

[0052] FIG9 is a diagram showing the circumferential force of the bounding membrane during the expansion process shown in FIG2 ;

[0053] FIG10 is a schematic diagram of the wrinkle structure on the restraining membrane of a TIPS covered stent provided in one embodiment of the present invention;

[0054] FIG11 is a schematic diagram showing the change process of the wrinkle structure on the constraining membrane during the expansion of the TIPS covered stent provided by one embodiment of the present invention;

[0055] FIG12 is a schematic structural diagram of a TIPS covered stent provided by another embodiment of the present invention after the restraining membrane is deployed;

[0056] FIG13 is a partial schematic diagram of the connection portion of the tie film shown in FIG12 being connected to the covering film segment. DETAILED DESCRIPTION

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0058] In the description of the present invention, it should be understood that the terms "including" and "having" and any variations thereof used herein are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0059] In addition, in the present invention, unless otherwise clearly stipulated and limited, the terms "connect", "connected", "fixed", "installed", etc. should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0060] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0062] In various embodiments of the present invention, the terms "distal" and "distal side" refer to the end or side away from the operator during a surgical procedure, and "proximal" and "proximal side" refer to the end or side closer to the operator during a surgical procedure. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0063] Figure 1 is a schematic structural diagram of a TIPS coated stent provided in one embodiment of the present invention, Figure 2 is a schematic structural diagram of a TIPS coated stent provided in one embodiment of the present invention after the restraining membrane is unfolded, and Figure 3 is a partial schematic diagram of the connection portion of the restraining membrane shown in Figure 2 connected to the coated segment.

[0064] Referring to Figure 1 , this embodiment provides a TIPS covered stent, comprising a proximal covered segment 1, a distal bare segment 2, and a constraining membrane 3. Covered segment 1 comprises a first frame 11 and a covering 12. The distal end of first frame 11 is connected to the proximal end of bare segment 2, covering 12 is at least partially fixed to the outside of first frame 11, and constraining membrane 3 covers at least a portion of covering 12 on the outside of covering 12.

[0065] The coating segment 1 has a first radial dimension and a second radial dimension, the second radial dimension is larger than the first radial dimension, and the restraining film 3 is configured to restrain the coating segment 1 so that the coating segment 1 is in the first radial dimension, and can release the restraint of the coating segment 1 under the action of external force so that the coating segment 1 is in the second radial dimension.

[0066] Referring to Figures 1 and 2 , the tie film 3 includes a main body 31, a first end located proximal to the main body 31, and a second end located distal to the main body 31. The first and / or second ends are provided with a connecting portion 32 for fixed connection to the covering 12. The circumferential dimension of the connecting portion 32 at the end distal to the main body 31 is smaller than the circumferential dimension of the end proximal to the main body 31. The circumferential dimension of the connecting portion 32 at the covering segment 1 is measured based on the tie film 3 wrapped around the covering segment 1.

[0067] The TIPS stent graft of this embodiment is used to establish a blood flow channel between the hepatic vein and the portal vein. The coated segment 1 is placed in the liver parenchyma and communicates with the hepatic vein; the bare segment 2 is placed through a puncture port in the portal vein to provide communication and fixation. The binding membrane 3, disposed on the graft 12, has a connecting portion 32 for securing it to the graft 12. The circumferential dimension of the end of the connecting portion 32 distal to the main body 31 is smaller than the circumferential dimension of the end proximal to the main body 31. This simplifies the securing mechanism between the binding membrane 3 and the graft 12. When the TIPS stent graft is pressed into the sheath of a delivery device, the shape of the connecting portion 32 reduces the effort required to press the portion of the graft 1 corresponding to the connecting portion 32. The TIPS stent graft with the binding membrane 3 facilitates smoother insertion and sheath withdrawal, reducing the risk of curling of the binding membrane 3. It also reduces the risk of separation of the binding membrane 3 from the graft 12 and fracture of the binding membrane 3 at the junction with the graft 12.

[0068] The first frame 11 of this embodiment is cylindrical and is used to support the blood flow channel. The cylindrical shape can be a straight cylinder with a constant diameter or a cylinder with a variable diameter. For example, the diameter of the proximal end of the first frame 11 is smaller than the diameter of the distal end. In one example, the first frame 11 includes multiple first structural units, which are spirally distributed along the axial direction of the coating segment 1. In this example, there are no specific restrictions on the shape of the first structural units, as long as the first structural units have protrusions 111. Recesses 112 are formed between adjacent first structural units. For example, the shape of the first structural units can be triangular, semicircular, arc-shaped, etc. In this way, multiple first structural units are connected in sequence to form protrusions 111 facing the distal end and recesses 112 facing the proximal end. In another example, the first frame 11 includes multiple structural components, which are spaced apart along the axial direction of the coating segment 1. Adjacent structural components are connected by the coating 12, or by connectors. Each structural component includes multiple first structural units arranged circumferentially along the coating segment 1. Similarly, it is sufficient for the first structural units to have protrusions 111. Recesses 112 are formed between adjacent first structural units. For example, the shape of the first structural unit is triangular, semicircular, arc-shaped, etc. In this way, multiple first structural units in the structural assembly are sequentially connected to form a protrusion 111 toward the distal end and a recess 112 toward the proximal end. In one example, the first frame 11 is made of a biocompatible alloy material with shape memory function. For example, the first frame 11 can be made of nickel-titanium alloy. Protrusion and recess are relative concepts. When observing the first structural unit from one direction, it includes a protrusion, while when observing from the opposite direction, the protrusion in the first structural unit is a recess. For the convenience of description, in this embodiment, observation is made from the proximal end to the distal end.

[0069] In this embodiment, the coating 12 is coated on the outside of the first frame 11 to prevent the liquid in the liver parenchyma, such as liver juice, from entering the blood flow channel to narrow the TIPS coated stent. In one example, the coating 12 is also coated on the inner side of the first frame 11 to further prevent the liquid in the liver parenchyma from penetrating. In one example, the proximal shape of the coating 12 matches the proximal shape of the first frame 11. After the TIPS coated stent is implanted, the proximal end of the coating 12 matches the proximal shape of the first frame 11, thereby preventing the coating 12 located at the proximal end face of the first frame 11 from folding toward the inside of the shunt channel due to insufficient expansion. The folding of the coating 12 toward the inside of the shunt channel will affect the inner cavity space of the shunt channel.

[0070] In this embodiment, there is no particular limitation on the method for fixing the membrane 12 to the first frame 11. For example, the membrane 12 and the first frame 11 may be fixed by bonding, suturing, anchoring, sintering, etc. In this embodiment, there is no particular limitation on the material of the membrane 12. For example, the membrane 12 may be made of PTFE (polytetrafluoroethylene) or ePTFE (expanded polytetrafluoroethylene).

[0071] In this embodiment, the binding membrane 3 disposed on the coating segment 1 is cylindrical. The binding membrane 3 has radial dimensions that match the radial dimensions of the coating segment 1 to constrain the coating segment 1. For example, the binding membrane 3 has a radial dimension slightly larger than the first radial dimension, so that the coating segment 1 has the first radial dimension when released within the liver parenchyma. The binding membrane 3 is radially expanded by an external force (e.g., balloon dilation). After plastic deformation, the binding membrane 3 has a radial dimension slightly larger than the second radial dimension. The coating segment 1 expands with the radial expansion of the binding membrane 3 and is reconstrained by the binding membrane 3 to the second radial dimension, thereby achieving the purpose of diameter change. The connecting portion 32 is circumferentially disposed at the first end and / or the second end. Exemplarily, the first end is proximal to the proximal end of the coating 12, and the second end is proximal to the distal end of the coating 12. The main body 31 between the first and second ends is directly wrapped around the coating 12, simplifying the process of fixing the binding membrane 3 to the coating 12 and saving preparation time.

[0072] This embodiment has no special restrictions on the specific shape of the connecting portion 32, as long as the size of the end of the connecting portion 32 away from the main body 31 in the circumferential direction of the coating segment 1 is smaller than the size of the end close to the main body 31 in the circumferential direction of the coating segment 1. In this way, the connecting portion 32 is smoother when inserted into the sheath or when the sheath is withdrawn. In one example, the farther the axial distance between the connecting portion 32 and the main body 31, the smaller the size of the connecting portion 32 in the circumferential direction of the coating segment 1. In one example, the size of the connecting portion 32 in the circumferential direction of the coating segment 1 decreases proportionally with the axial distance from the connecting portion 32 to the main body 31. Exemplarily, the connecting portion 32 is triangular or trapezoidal when unfolded. In one example, the size of the connecting portion 32 in the circumferential direction of the coating segment 1 decreases non-proportionally with the axial distance from the connecting portion 32 to the main body 31. Exemplarily, the connecting portion 32 is arc-shaped, sinusoidal, semi-elliptical, or semi-waist-drum-shaped when unfolded.

[0073] Here, the first end and / or the second end are provided with a connection portion 32 for fixed connection to the covering film 12, including the first end of the binding film 3 being provided with a connection portion 32 for fixed connection to the covering film 12, or the second end of the binding film 3 being provided with a connection portion 32 for fixed connection to the covering film 12, or both the first and second ends of the binding film 3 being provided with a connection portion 32 for fixed connection to the covering film 12. The connection between the connection portion 32 and the covering film 12 can be achieved by bonding, sewing, or other methods.

[0074] When both the first and second ends of the tie film 3 are provided with connecting portions 32, the number of connecting portions 32 provided at the first end may be equal to the number of connecting portions 32 provided at the second end, the number of connecting portions 32 provided at the first end may be greater than the number of connecting portions 32 provided at the second end, or the number of connecting portions 32 provided at the first end may be less than the number of connecting portions 32 provided at the second end. In the circumferential direction of the covering segment 1 and / or the axial direction of the covering segment 1, the size of the connecting portion 32 provided at the first end may be equal to the size of the connecting portion 32 provided at the second end, the size of the connecting portion 32 provided at the first end may be greater than the size of the connecting portion 32 provided at the second end, or the size of the connecting portion 32 provided at the first end may be less than the size of the connecting portion 32 provided at the second end.

[0075] Please refer to Figures 1 and 8. In the axial direction of the coating segment 1, the length of the binding membrane 3 is less than the length of the coating 12, and the binding membrane 3 is located near the middle of the coating segment 1. That is, there is a distance from the first end of the binding membrane 3 to the proximal end of the coating 12 and / or from the second end of the binding membrane 3 to the distal end of the coating 12. In this way, when the TIPS coated stent is pressed and gripped into the sheath of the delivery device, the proximal end of the coating 12 first enters the sheath for a distance before the binding membrane 3 enters the sheath, so that less force is required to be applied when starting to press and grip, and the sheathing is relatively smooth. After the stent is implanted in the body, when the blood flow enters the coating segment 1, it first passes through the part of the distal end of the coating 12 that is not covered with the binding membrane 3 (with a larger diameter), and then gradually flows through the part of the binding membrane 3 (with a smaller diameter). The blood flow transition is natural and the impact on the stent is small. When the stent is dilated and reduced in diameter by balloon expansion, the part covered with the binding membrane 3 is mainly expanded. Because a distance at each end of the graft 12 is left uncovered by the tethering membrane 3, the expansion area of ​​the tethering membrane 3 is smaller, making stent expansion more convenient. In one example, the distance from the first end of the tethering membrane 3 to the proximal end of the graft 12 and / or the distance from the second end of the tethering membrane 3 to the distal end of the graft 12 is 5-10 mm. In one example, the distance from the first end of the tethering membrane 3 to the proximal end of the graft 12 is equal to the distance from the second end of the tethering membrane 3 to the distal end of the graft 12. In another example, the distance from the first end of the tethering membrane 3 to the proximal end of the graft 12 is different from the distance from the second end of the tethering membrane 3 to the distal end of the graft 12.

[0076] When the distance from the first end of the binding membrane 3 to the proximal end of the graft 12 is not equal to the distance from the second end of the binding membrane 3 to the distal end of the graft 12, the distance from the first end of the binding membrane 3 to the proximal end of the graft 12 may be smaller than the distance from the second end of the binding membrane 3 to the distal end of the graft 12, or the distance from the first end of the binding membrane 3 to the proximal end of the graft 12 may be larger than the distance from the second end of the binding membrane 3 to the distal end of the graft 12. When the length of the binding membrane 3 is constant, setting the distance from the first end of the binding membrane 3 to the proximal end of the graft 12 to be larger than the distance from the second end of the binding membrane 3 to the distal end of the graft 12 allows for smoother insertion of the TIPS stent graft.

[0077] In this embodiment, the portion of the connection portion 32 provided at the first end that is away from the main body portion 31 is located distally to the first structural unit that is closest in the axial direction, and the portion of the connection portion 32 provided at the second end that is away from the main body portion 31 is located proximal to the first structural unit that is closest in the axial direction. When the TIPS stent is pressed and gripped to enter the lumen of the sheath, the first structural unit located proximal to the connection portion 32 at the first end of the first frame 11 first contacts the lumen of the sheath, and the connection portion 32 provided at the first end is located distally to the first structural unit, thereby reducing the probability of contact with the lumen of the sheath, thereby avoiding the occurrence of curling. Similarly, when the sheath is withdrawn, the lumen of the sheath also first contacts the first structural unit located distally to the connection portion 32 at the second end of the first frame 11, and the connection portion 32 provided at the second end is located proximal to the first structural unit, thereby reducing the probability of contact with the lumen of the sheath, thereby avoiding the occurrence of curling.

[0078] Referring to Figures 2 and 4 , the connecting portion 32 includes a top region 321 and a connecting region 322. The portion of the connecting portion 32 distal to the main portion 31 is defined as the top region 321, and the portion of the connecting portion 32 proximal to the main portion 31 is defined as the connecting region 322. The top region 321 is used for fixed connection to the covering 12. The connecting region 322 is connected to another connecting portion 32. The constraining membrane 3 is connected to the covering 12 only via a number of top regions 321, significantly reducing the process and difficulty of connecting the binding covering 3 and the covering 12, thereby simplifying stent fabrication. In one example, the top region 321 forms a concave structure, while the connecting region 322 forms a convex structure. In one example, the edge between the top region 321 and the connecting region 322 can be straight, in which case the unfolded shape of the connecting portion 32 can be a triangle, trapezoid, or the like. In another example, the edge between the top region 321 and the connecting region 322 can be curved, in which case the unfolded shape of the connecting portion 32 can be an arc, a sine wave, a semi-ellipse, a semi-drum, or the like.

[0079] In one example, for the connection portion 32 disposed at the first end, the top region 321 is disposed on the distal side of the recess 112 corresponding to the first structural unit closest in the axial direction, and the connection region 322 is disposed on the distal side of the protrusion 111 near the recess 112. For the connection portion 32 disposed at the second end, the top region 321 is disposed on the proximal side of the protrusion 111 corresponding to the first structural unit closest in the axial direction, and the connection region 322 is disposed on the proximal side of the recess 112 near the protrusion 111. Here, the protrusion 111 near the recess 112 includes the protrusion 111 adjacent to the recess 112 (i.e., there is no first structural unit between the two). For example, the recess 112 and the protrusion 111 shown in FIG3. The protrusion 111 near the recess 112 also includes the protrusion 111 separated from the recess 112 by several first structural units. For example, the recess 112 and the protrusion 111 shown in FIG7.

[0080] In one example, the first frame 11 includes a plurality of structural components, which are spaced apart along the axial direction of the coating segment 1, and each structural component includes a plurality of first structural units arranged circumferentially along the coating segment 1. The connecting portions 32 are circumferentially arranged at the first and / or second ends of the main body 31 and are located on the same plane perpendicular to the axis. As shown in FIG2 , after the restraining membrane 3 is unfolded, the connecting portions 32 are arranged flush at the first and second ends of the restraining membrane 3 in a direction perpendicular to the axial direction of the coating segment 1. In an alternative example, the first structural units are directly spirally distributed along the axial direction of the coating segment 1, and the connecting portions 32 can be arranged in a spiral shape. When the restraining membrane 3 is unfolded, the multiple connecting portions 32 can be arranged axially to the left or right from top to bottom. As shown in FIG4 , at the first end of the restraining membrane 3, the multiple connecting portions 32 are arranged axially to the right from top to bottom.

[0081] In one example, a connection portion 32 is provided at the first end, wherein a top region 321 of the connection portion 32 is located distally of the recess 112, a connection region 322 of the connection portion 32 is located distally of the protrusion 111, and the protrusion 111 and the recess 112 are adjacent, i.e., there is no first structural unit intervening therebetween. A connection portion 32 is provided at the second end, wherein a top region 321 of the connection portion 32 is located proximal to the protrusion 111, a connection region 322 of the connection portion 32 is located proximal to the recess 112, and the recess 112 and the protrusion 111 are adjacent, i.e., there is no first structural unit intervening therebetween. Thus, the arrangement of the top region 321 and the connection region 322 of the connection portion 32 corresponds to the arrangement of adjacent recesses 112 and protrusions 111 of the first frame, respectively. When the connection portion 32 at the first end is connected to the coating 12, the connection portion 32 at the first end completely wraps around the area covered by the first structural unit, without the connection portion 32 overlapping the first structural unit, making insertion into the sheath smoother. Furthermore, simply connecting the top region 321 of the connecting portion 32 at the first end to the covering 12 distal to the recess 112 facilitates the connection between the tethering membrane 3 and the covering 12. Similarly, when the connecting portion 32 at the second end is connected to the covering 12, the connecting portion 32 at the second end completely wraps around the area covered by the first structural unit, without overlapping the connecting portion 32 on the first structural unit, making sheath retraction smoother. Furthermore, simply connecting the top region 321 of the connecting portion 32 to the covering 12 proximal to the protrusion 111 facilitates the connection between the tethering membrane 3 and the covering 12.

[0082] Referring to Figures 2 and 3 , each structural component of the first frame 11 has six first structural units, each in a triangular shape. The six first structural units are sequentially connected to form six recesses 112 and six protrusions 111. At the proximal end (i.e., the first end) of the restraining membrane 3, there are six connecting portions 32, each with a triangular outer contour. Six connecting regions 322 are directly connected in sequence. In the unfolded view of the restraining membrane 3, the six connecting portions 32 are aligned in a direction perpendicular to the axial direction. The number of connecting portions 32 is the same as the number of first structural units. Each top region 321 is located distally of a recess 112 of the structural component, and the connecting region 322 is located distally of the protrusion 111 adjacent to the recess 112. The connecting portions 32 at the distal end (i.e., the second end) of the restraining membrane 3 are similarly configured.

[0083] In one example, the contour edge between the top region 321 and the connecting region 322 of the connecting portion 32 is parallel to the contour edge between the protrusion 111 and the recess 112 of the corresponding first structural unit. In this embodiment, the contour edge of the connecting portion 32 is a straight line, and the contour edge of the first structural unit is also a straight line, and the two are parallel to each other. When connecting the tie film 3 to the covering film 12 of the covering film segment 1, the contour edge of the connecting portion 32 can be arranged along the contour edge of the first structural unit, which simplifies the manufacturing method of connecting the tie film 3 to the covering film 12.

[0084] Figure 9 is a diagram illustrating the circumferential forces acting on the constraining membrane 3 during expansion of the TIPS stent graft shown in Figure 2 . The following, combined with an analysis of the forces acting on the constraining membrane 3 during expansion of the TIPS stent graft, details the mechanism by which the connecting portion 32 in the aforementioned embodiment prevents breakage and separation at the junction with the graft 12. For ease of explanation, Figure 9 illustrates the constraining membrane 3 in its expanded state.

[0085] Please refer to Figures 1 and 9. When the TIPS stent graft expands in diameter, the bundle membrane 3 on the TIPS stent graft is subjected to not only radial outward forces (i.e., forces perpendicular to the paper in Figure 9), but also deformation forces (which may be elastic or plastic) generated by the deformation of the bundle membrane 3 itself. This force is applied on the circumferential surface (in Figure 9, upward and downward forces). The circumferential force applied to any point on the bundle membrane 3 is positively correlated with the length change, and particularly in the initial stage, the relationship is nearly proportional, i.e., the greater the length change, the greater the corresponding force.

[0086] As shown in Figure 9, at any point A on the main body 31 of the tying membrane 3 (within the dashed box), the circumferential tension Fa exerted on the tying membrane 3 is measured, and the expanded length La of the tying membrane 3 (i.e., the circumference of the tying membrane is La) is measured. Assuming the diameter before expansion is D1, the expanded length La = π*D1, the diameter after expansion is D2, and the change in diameter after expansion is ΔD = D2-D1. Therefore, the change (increase) in the expanded length ΔLa is πΔD. The rate of change in the expanded length before and after expansion is ΔLa / La = π*(D2-D1) / (π*D1) = ΔD / D1. Therefore, the circumferential tension Fa exerted on the tying membrane 3 at point A is proportional to ΔD / D1, i.e., Fa∝ΔLa / La = ΔD / D1.

[0087] At a point B within the connection 32, the corresponding expanded length is Lb. During expansion, because the restraining membrane 3 at point B does not cover the entire circumference, the change in expanded length after expansion is ΔLb = (ΣLb / La) * ΔLa. Here, ΣLb is the sum of the expanded lengths of all the connections at point B in the circumferential direction. The rate of change in the expanded length at point B before and after expansion is ΔLb / La = ((ΣLb / La) * ΔLa) / La = (ΣLb / La) * (ΔD / D1). For ΣLb / La, when point B is on the zero-boundary imaginary line, ΣLb = La and ΣLb / La = 1. When point B is at the vertex of the top region 321 of the triangular connection, ΣLb = 0 and ΣLb / La = 0. Therefore, the circumferential tensile force Fb applied to the constraining membrane 3 at point B is proportional to (ΣLb / La)*(ΔD / D1), i.e., Fb ∝ ΔLb / La = (ΣLb / La)*(ΔD / D1). For the same piece of fabric, with the same material, physical properties, and strength, Fb < Fa is less than Fa when point B is at the connection portion 32 and point A is at the main body 31. In an extreme case, when point B is at the vertex of the top region of the triangular connection portion 32, ΣLb is zero, and the force Fb is also zero. Therefore, during expansion, the force applied to the top region 321 of the connection portion 32 is relatively small. Securing the constraining membrane 3 to the stent coating 12 at the top region 321 prevents the constraining membrane 3 from separating from the stent coating 12 and also prevents the constraining membrane 3 from tearing.

[0088] Figure 4 is a schematic diagram of the structure of a TIPS covered stent graft after deployment, provided by another embodiment of the present invention. Figure 5 is a partial schematic diagram of the deployment membrane shown in Figure 4 connected to the covered segment. Referring to Figures 4 and 5, the difference from the above-described embodiment is that the first frame 11 includes multiple first structural units, which are arranged spirally along the axial direction of the covered segment 1. When deployed, the multiple connecting portions 32 of the deployment membrane 3 can be arranged axially to the left or right from top to bottom. In one example, each turn of the first frame 11 (i.e., within each pitch) includes six first structural units, each of which is triangular in shape. The six first structural units are sequentially connected to form six depressions and six protrusions. The connecting portions 32 at the first end of the deployment membrane 3 are also triangular in shape, with six corresponding connecting portions 32 arranged spirally, with six connecting regions 322 directly connected in sequence. At the first end of the deployment membrane 3, the multiple connecting portions 32 are arranged axially to the right from top to bottom. The top region 321 of the connecting portion 32 at the first end is located distally of the recess 112 corresponding to the first structural unit closest in the axial direction, and the connecting region 322 of the connecting portion 32 is located distally of the protrusion 111 adjacent to the recess 112. Similarly, the top region 321 of the connecting portion 32 at the second end is located proximal to the protrusion 111 corresponding to the first structural unit closest in the axial direction, and the connecting region 322 of the connecting portion 32 is located proximal to the recess 112 adjacent to the protrusion 111.

[0089] FIG6 is a schematic diagram of the structure of a TIPS stent graft provided by another embodiment of the present invention after the restraining membrane is deployed, FIG7 is a partial schematic diagram of the restraining membrane shown in FIG6 connected to the graft segment, and FIG8 is a schematic diagram of the structure of the TIPS stent graft provided with the restraining membrane shown in FIG6. Referring to FIG6-8, in an alternative embodiment, a connecting portion 32 is provided at the first end, a top region 321 of the connecting portion 32 is disposed distally of the recess 112 of the axially closest first structural unit, a connecting region 322 of the connecting portion 32 is disposed distally of the protrusion 111, and a plurality of first structural units are spaced between the recess 112 corresponding to the top region 321 and the protrusion 111 corresponding to the connecting region 322. Alternatively, a connecting portion 32 is provided at the second end, with a top region 321 of the connecting portion 32 positioned proximal to the protrusion 111 of the first structural unit closest in the axial direction, and a connecting region 322 of the connecting portion 32 positioned proximal to the recess 112. Furthermore, the protrusion 111 corresponding to the top region 321 and the recess 112 corresponding to the connecting region 322 are spaced apart by a number of first structural units. In this case, the number of connecting portions 32 does not correspond to the number of first structural units or protrusions 111 within the first structural unit; the number of connecting portions 32 is smaller than the number of first structural units. This simplifies the manufacture of the restraining film 3 and makes it easier to securely connect it to the covering segment 1 while maintaining connection strength.

[0090] In one example, each structural component of the first frame 11 has six first structural units, each of which is triangular in shape. The six first structural units are sequentially connected to form six recesses and six protrusions. The connecting portion 32 of the first end of the restraining membrane 3 is also triangular in shape, with two connecting portions 32 arranged circumferentially. This differs from the above-described embodiment in that, from top to bottom in FIG7 , the top region 321 of the first connecting portion 32 of the first end is located distally to the recess 112 of the first structural unit closest in the axial direction, i.e., distally to the second recess 112 in the figure, while the connecting region 322 is located distally to the third protrusion 111. Here, the second recess 112 and the third protrusion 111 are separated by one first structural unit. The connecting portion 32 of the second end can be arranged similarly.

[0091] In the above embodiment, the top region 321 of one connecting portion 32 is not connected to the top region 321 of another connecting portion 32, while the connecting region 322 of one connecting portion 32 is directly connected to the connecting region 322 of another connecting portion 32. For example, in the connecting portions 32 shown in Figures 2, 4, and 6, for all connecting portions 32 disposed at the first end of the tethering membrane 3, all connecting regions 322 are directly connected in sequence. For all connecting portions 32 disposed at the second end of the tethering membrane 3, all connecting regions 322 are directly connected in sequence. Figure 12 is a schematic diagram of the structure of a TIPS stent graft after deployment of the tethering membrane according to another embodiment of the present invention. Figure 13 is a partial schematic diagram of the connecting portion of the tethering membrane shown in Figure 12 connected to the graft segment. In this embodiment, the top region 321 of one connecting portion 32 is not connected to the top region 321 of another connecting portion 32, and the connecting region 322 of one connecting portion 32 is not directly connected to the connecting region 322 of another connecting portion 32, but is connected via the main body 31. The top region 321 of the connecting portion 32 at the first end is similarly positioned distally of the recess 112 of the first structural unit closest in the axial direction, and the connecting region 322 is positioned distally of the protrusion 111 adjacent to the recess 112 corresponding to the top region 321. The connecting portion 32 at the second end can be similarly positioned. As shown in Figures 12 and 13, compared to the tie film shown in Figure 2, the tie film has only three connecting portions 32 at the first and second ends. The connecting regions 322 of each connecting portion 32 are not directly connected, but rather connected via the main body 31. The top region 321 of the connecting portion 32 at the first end is positioned distally of the recess 112 of the first structural unit closest in the axial direction, and the connecting region 322 is positioned distally of the protrusion 111, with the recess 112 adjacent to the protrusion 111.

[0092] Figure 10 is a schematic diagram of the corrugated structure on the constraining membrane of a TIPS stent graft according to one embodiment of the present invention. Figure 11 is a schematic diagram of the changing corrugated structure on the constraining membrane during expansion of the TIPS stent graft according to one embodiment of the present invention. Referring to Figures 10 and 11, the main body 31 also has axially distributed corrugated structures 33. Corrugated structures 33 are used to prevent axial shortening of the constraining membrane 3 during expansion (i.e., when the graft segment 1 transitions from a first radial dimension to a second radial dimension). Generally, during expansion of the TIPS stent graft, the inherent forces of the constraining membrane 3 cause the constraining membrane 3 to shorten axially, thereby causing the graft segment 1 to experience undesirable axial shortening. In this embodiment, the corrugated structures 33 offset the effects of these inherent forces, preventing axial shortening of the constraining membrane 3. As the graft segment 1 expands, the radial dimension of the constraining membrane 3 increases, and the corrugated structures 33 gradually decrease until they disappear. The cross-section (here, the cross-section along the axial direction) of the corrugated structures 33 can be composed of multiple irregular shapes or multiple regular shapes. For example, the cross-section of the pleated structure 33 may be composed of a plurality of regular shapes such as trapezoids, rectangles, or triangles. In this embodiment, there is no particular limitation on the specific size of the pleated structure 33, as long as it can prevent the axial shortening of the constraining membrane 3.

[0093] In one embodiment, the bare segment 2 includes a second frame 21. The second frame 21 is cylindrical. In this embodiment, at least a portion of the second frame 21 has a radial dimension greater than that of the first frame 11. For example, the radial dimension of the proximal end of the second frame 21 (i.e., the end connected to the coated segment 1) is equal to that of the first frame 11, but smaller than the radial dimension of the distal end (the end distal to the coated segment 1). This allows the bare segment 2 located in the portal vein to mitigate the impact of blood flow on the stent, which can cause the TIPS stent graft to move. Similarly, the second frame 21 is made of an alloy material with shape memory properties, such as nickel-titanium alloy. The second frame 21 includes at least second structural units, with multiple second structural units distributed axially along the bare segment 2. This embodiment does not specifically limit the shape of the second structural units. For example, the second structural units can be wavy, with adjacent second structural units intertwined, such that the crests of one second structural unit intertwine with the troughs of another adjacent second structural unit.

[0094] Referring to Figure 1 , imaging structures 4 are provided at both the proximal and distal ends of the coated segment 1. These structures 4 can be visualized in diagnostic equipment such as X-rays, CT scans, and MRIs, demonstrating the position of the TIPS stent graft within the human body during surgery. These structures 4 can be developed in the form of a development ring or a development tape. For example, a development ring is provided at the proximal end of the coated segment 1, and a development tape is provided at the junction of the coated segment 1 and the bare segment 2.

[0095] The TIPS coated stent provided by an embodiment of the present invention includes a coated segment at the proximal end, a bare segment at the distal end, and a restraining membrane, the coated segment includes a first frame and a coating, the distal end of the first frame is connected to the proximal end of the bare segment, the coating at least covers and is fixed to the outside of the first frame, and the restraining membrane covers at least part of the coating on the outside of the coating; the coated segment has a first radial dimension and a second radial dimension, the second radial dimension is larger than the first radial dimension, the restraining membrane is configured to restrain the coated segment so that the coated segment is in the first radial dimension, and can expand the radial dimension under the action of external force so that the coated segment is restrained in the second radial dimension; the restraining membrane includes a main body, a first end located at the proximal end of the main body, and a second end located at the distal end of the main body, the first end and / or the second end is provided with a connecting portion for fixedly connecting to the coating, the size of the end of the connecting portion away from the main body in the circumferential direction of the coating segment is smaller than the size of the end of the connecting portion close to the main body in the circumferential direction of the coating segment. In this way, the fixation method between the binding membrane and the covering is simpler and faster; the force required when pressing and gripping the covering section is smaller, and it is easier to press and grip; when the TIPS covered stent is inserted into the sheath, under the condition of a certain space in the inner cavity of the sheath, the resistance of the part of the TIPS covered stent provided with the binding membrane when pressing into the sheath or the sheath is withdrawn is reduced, and the probability of curling of the binding membrane is also reduced; because the connecting part of the binding membrane is subjected to less force at the connection with the covering, when the TIPS covered stent changes diameter and expands, the connection part of the binding membrane is avoided from breaking at the connection with the covering, and the binding membrane is avoided from separating from the covering.

[0096] In the above description, the reference terms "one embodiment", "some embodiments", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0097] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A TIPS coated stent, comprising a proximal coated segment, a distal bare segment and a restraining membrane, wherein the coated segment comprises a first frame and a coating; The distal end of the first frame is connected to the proximal end of the bare segment, the covering film at least covers and is fixed to the outside of the first frame, and the binding film covers at least a portion of the covering film on the outside of the covering film; The coating segment has a first radial dimension and a second radial dimension, the second radial dimension is larger than the first radial dimension, the restraining film is configured to restrain the coating segment so that the coating segment is in the first radial dimension, and can expand the radial dimension under the action of an external force so that the coating segment is restrained in the second radial dimension; The restraining membrane includes a main body, a first end located at the proximal end of the main body and a second end located at the distal end of the main body, the first end and / or the second end is provided with a connecting portion for fixedly connecting with the coating, and the dimension of the end of the connecting portion away from the main body in the circumferential direction of the coating segment is smaller than the dimension of the end close to the main body in the circumferential direction of the coating segment.

2. The TIPS covered stent according to claim 1, wherein: The greater the axial distance between the connecting portion and the main body portion, the smaller the dimension of the connecting portion in the circumferential direction of the coating segment.

3. The TIPS covered stent according to claim 1, wherein: In the axial direction of the coating segment, the length of the binding film is smaller than the length of the coating, and the binding film is located in the middle of the coating segment.

4. The TIPS covered stent according to claim 3, wherein: The distance from the first end of the binding membrane to the proximal end of the covering membrane is 5-10 mm; and / or, The distance from the second end of the binding film to the distal end of the covering film is 5-10 mm.

5. The TIPS covered stent according to claim 3, wherein: The distance from the first end of the binding film to the proximal end of the covering film is not equal to the distance from the second end of the binding film to the distal end of the covering film.

6. The TIPS covered stent according to claim 1, wherein: The connecting portion comprises a top area and a connecting area, wherein the top area is away from the main body and is used for being fixedly connected to the covering film, and the connecting area is close to the main body and connected to another connecting portion.

7. The TIPS covered stent according to claim 1, wherein: The first frame includes a plurality of first structural units, at least some of which are connected in sequence; For the connecting portion disposed at the first end of the tethering membrane, a portion of the connecting portion away from the main body portion is located at a distal side of the first structural unit that is closest in axial direction; For the connecting portion disposed at the second end of the tethering membrane, a portion of the connecting portion away from the main body portion is located at a proximal side of the first structural unit that is closest in the axial direction.

8. The TIPS covered stent according to claim 7, wherein: A plurality of the first structural units are sequentially connected to form a protrusion toward the distal end and a depression toward the proximal end; The connecting portion includes a top area and a connecting area, the portion of the connecting portion away from the main body is defined as the top area, the top area is used to be fixedly connected to the covering film, and the connecting portion close to the main body is defined as the connecting area, and the connecting area is connected to another connecting portion; For the connection portion disposed at the first end of the tie film, the connection area is disposed on the distal side of the protrusion near the depression; For the connection portion disposed at the second end of the tie film, the connection region is disposed on the proximal side of the depression near the protrusion.

9. The TIPS covered stent according to claim 8, wherein: The connection region of the connection part is directly connected to the connection region of another connection part; or, The connection region of the connection part and the connection region of another connection part are connected through the main body.

10. The TIPS covered stent according to claim 8, wherein: A contour edge of the connecting portion between the top region and the connecting region is parallel to a contour edge between the protrusion and the recess of the corresponding first structural unit.

11. The TIPS covered stent according to claim 8, wherein: For the connecting portion provided at the first end of the binding film, the depression corresponding to the top area and the protrusion corresponding to the connecting area are spaced apart by a plurality of the first structural units; For the connecting portion disposed at the second end of the restraining film, a plurality of the first structural units are spaced between the protrusion corresponding to the top area and the depression corresponding to the connecting area.

12. The TIPS covered stent according to claim 8, wherein: For the connecting portion disposed at the first end of the tie film, the depression corresponding to the top area is adjacent to the protrusion corresponding to the connecting area; For the connecting portion disposed at the second end of the restraining film, the protrusion corresponding to the top area is adjacent to the depression corresponding to the connecting area.

13. The TIPS covered stent according to claim 12, wherein: For all the connection portions disposed at the first end of the tie film, all the connection areas are directly connected in sequence; For all the connection portions disposed at the second end of the tie film, all the connection areas are directly connected in sequence.

14. The TIPS covered stent according to any one of claims 7 to 13, wherein: A plurality of the first structural units are distributed in an axial spiral along the coating section; or, The first frame includes a plurality of structural components, and the plurality of structural components are arranged at intervals along the axial direction of the coating segment, and each of the structural components includes a plurality of the first structural units distributed circumferentially along the coating segment; adjacent structural components are connected via the coating, or adjacent structural components are connected via connectors.

15. The TIPS covered stent according to claim 14, wherein: When a plurality of the first structural units are spirally distributed along the axial direction of the coating segment, the connecting portions are spirally arranged in the same direction; When the first structural units in the structural assembly are distributed circumferentially along the coating segment and are located in a same plane perpendicular to the axial direction, the connecting portions are arranged circumferentially and are located in a same plane perpendicular to the axial direction.

16. The TIPS covered stent according to claim 1, wherein: The main body has a corrugated structure, and the corrugated structure is used to prevent the main body from being axially shortened when the coating segment turns from the first radial dimension to the second radial dimension.

17. The TIPS covered stent according to claim 1, wherein: The bare segment includes a second frame, and a radial dimension of at least a portion of the second frame is greater than a radial dimension of the first frame.

Images