TIPS covered stent

Abstract

The present invention provides a TIPS stent graft, comprising a graft segment, a bare segment, and a constraining membrane. The graft segment comprises a first metal skeleton and a graft. The constraining membrane covers at least a portion of the graft outside the graft. The constraining membrane constrains the graft segment so that the graft segment is in a first radial dimension and can expand radially under the action of an external force so that the graft segment is constrained to a second radial dimension. The constraining membrane comprises a main body, a first end, and a second end. The first end and / or the second end is provided with a connecting portion, and the circumferential dimension of the graft segment at the end of the connecting portion away from the main body is smaller than the circumferential dimension of the graft segment at the end closer to the main body. The constraining membrane of the TIPS stent graft reduces resistance during insertion into a sheath or during sheath withdrawal, and also reduces the probability of the constraining membrane curling. When the TIPS stent graft changes diameter and expands, the connecting portion between the first and second ends of the constraining membrane is prevented from breaking or separating from the graft at the connection with the graft.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and more specifically, relates to a TIPS coated stent. Background Art

[0002] Globally, cirrhosis is the fourth leading cause of death (non-communicable diseases), following cancer, cardiovascular disease, and chronic lung disease. Cirrhosis alters liver tissue structure, causing compression and narrowing of blood vessels within the liver. Blood in the portal vein flows through the liver and returns to the heart via the hepatic vein. Consequently, when blood flow is impaired, portal vein pressure increases, leading to portal hypertension. Portal hypertension in cirrhosis can lead to complications such as esophageal-gastric variceal bleeding, intractable ascites, hepatic encephalopathy, and hepatorenal syndrome.

[0003] With the development of minimally invasive surgery, the transjugular intrahepatic portosystemic shunt (TIPS) procedure was invented and used for portal hypertension in cirrhosis. TIPS uses a special minimally invasive device, 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.

[0004] The TIPS covered stent usually consists of a bare segment and a covered segment. 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 TIPS, 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 liver detoxification and re-enter the blood circulation, excessive blood ammonia entering the brain can cause hepatic encephalopathy, which can severely cause the patient to fall into a coma or even die.

[0005] To address the issue of stent diameter selection, patent document US20010053929A1 proposes a variable-diameter stent graft. Specifically, a restraining membrane is inserted over the stent graft segment. The restraining membrane is connected to the stent graft segment's membrane and exerts a certain restraining force on the stent. Initially, the restraining membrane limits the stent graft's diameter. Then, external force expands the restraining membrane, causing it to plastically deform. The stent graft then expands with the membrane, effectively addressing the stent diameter selection issue. Since the binding membrane must be connected to the covering membrane at least at both ends, the two end faces of the binding membrane are straight, and the covered stent has the following problems: the gripping force will increase when the covered stent is pressed into the sheath, 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 binding membrane (even including connecting medium) is directly added to the outside of the covering, which further squeezes the space in the sheath, increases the difficulty of sheathing, and the end of the binding membrane is prone to curling when sheathing; since the binding membrane is connected to the covering membrane 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, since the binding membrane and the covering membrane are connected as a whole, the expansion of the binding membrane is constrained by the connection, and it is difficult to expand freely and plastically deform, thereby affecting the diameter change effect of the covering segment, and when the binding membrane expands, the connection between the binding membrane and the covering membrane is subjected to greater force, which makes it easy for the binding membrane to break at the connection and for the binding membrane and the covering to separate. Summary of the Invention

[0006] The purpose of the embodiments of the present invention is to provide a TIPS coated stent and a stent delivery system to solve one or more of the above-mentioned technical problems.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows: the present invention provides a TIPS covered stent, comprising a proximal covered segment, a distal bare segment and a restraining membrane, wherein the covered segment comprises a first metal skeleton and a covered membrane;

[0008] The distal end of the first metal skeleton 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 metal skeleton, and the restraining film covers at least a portion of the covering film on the outside of the covering film;

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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 for fixed connection with the covering film, and the connecting area is close to the main body and adjacent to the other connecting portion.

[0014] In one embodiment, the first metal skeleton includes a plurality of first structural units, at least some of which are connected in sequence;

[0015] When the first end is provided with the connecting portion, the portion of the connecting portion away from the main body is located on the far side of the first structural unit that is closest in the axial direction;

[0016] When the second end is provided with the connecting portion, the portion of the connecting portion away from the main body is located on the proximal side of the first structural unit that is axially closest.

[0017] In one embodiment, the first structural units are sequentially connected to form a protrusion toward the distal end and a depression toward the proximal end;

[0018] 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 adjacent to the other connecting portion;

[0019] For the connecting portion provided at the first end, the top region is provided on the distal side of the recess corresponding to the first structural unit closest in the axial direction, and the connecting region is provided on the distal side of the protrusion near the recess;

[0020] For the connecting portion arranged at the second end, the top region is arranged on the proximal side of the protrusion corresponding to the first structural unit closest in the axial direction, and the connecting region is arranged on the proximal side of the recess near the protrusion.

[0021] 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.

[0022] In one embodiment, the shape of the connecting portion matches the shape of the first structural unit, and the number of the connecting portions is the same as the number of the first structural units.

[0023] In one embodiment, when the first end is provided with the connecting portion, the depression adjacent to the top region of the connecting portion is not adjacent to the protrusion adjacent to the connecting region of the connecting portion;

[0024] When the second end is provided with the connecting portion, the protrusion adjacent to the top region of the connecting portion is not adjacent to the recess adjacent to the connecting region of the connecting portion.

[0025] In one embodiment, the first structural units are distributed in a spiral along the axial direction of the coating segment; or,

[0026] The first metal skeleton includes a plurality of structural components, the plurality of structural components are spaced apart along the axial direction of the coating segment, and adjacent structural components are connected by the coating, or adjacent structural components are connected by connecting pieces;

[0027] Each of the structural components includes a plurality of first structural units distributed along the circumference of the coating segment.

[0028] In one embodiment, when 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;

[0029] When the first structural units in the structural assembly are distributed circumferentially along the coating segment and are located in the same plane perpendicular to the axial direction, the connecting portions are arranged circumferentially and are located in the same plane perpendicular to the axial direction.

[0030] 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.

[0031] The TIPS coated stent provided by the present invention includes a coated segment at the proximal end, a bare segment at the distal end, and a restraining membrane, wherein the coated segment includes a first metal skeleton and a 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 an external force so that the coated segment is restrained in the second radial dimension, the TIPS coated stent can achieve the purpose of stent diameter change; 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 restraining membrane is connected to the coating through the connecting portion located at the first end and the second end of the main body. The fixed connection makes the fixing method between the binding membrane and the covering membrane simpler and faster; the size of the end of the connection part away from the main body in the circumferential direction of the covering membrane segment is smaller than the size of the end close to the main body in the circumferential direction of the covering membrane segment, so the force required when pressing and gripping the covering membrane segment 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 inner space of the sheath, the resistance of the binding membrane when pressing into the sheath or withdrawing the sheath is reduced, and the probability of curling of the binding membrane is also reduced; the connection part of the first end and the second end of the binding membrane is subjected to less force at the connection with the covering membrane, and when the TIPS covered stent changes diameter and expands, the connection part of the first end and the second end of the binding membrane will not separate from the covering membrane, thereby avoiding the connection part of the first end and the second end of the binding membrane at the connection with the covering membrane Breakage, separation from the covering membrane, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 A schematic structural diagram of a TIPS stent graft provided in one embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the structure of a TIPS covered stent provided by one embodiment of the present invention after the restraining membrane is deployed;

[0035] Figure 3 for Figure 2 A schematic structural diagram showing a connecting portion of the tie film connected to a covering film segment;

[0036] Figure 4 A schematic diagram of the structure of a TIPS covered stent after the restraining membrane is deployed, provided by another embodiment of the present invention;

[0037] Figure 5 for Figure 4 A schematic structural diagram showing the connection portion of the tie film being connected to the covering film segment;

[0038] Figure 6 A schematic diagram of the structure of a TIPS covered stent provided by another embodiment of the present invention after the restraining membrane is deployed;

[0039] Figure 7 for Figure 6 A schematic structural diagram showing a connecting portion of the tie film connected to a covering film segment;

[0040] Figure 8 For the Figure 6 Schematic diagram of the structure of the TIPS covered stent with the bound membrane shown;

[0041] Figure 9 for Figure 2 The diagram of the circumferential force acting on the bounding membrane during the expansion process is shown;

[0042] Figure 10 A schematic diagram of the wrinkle structure on the restraining membrane of a TIPS covered stent provided in one embodiment of the present invention;

[0043] Figure 11 A schematic diagram of the change process of the wrinkle structure on the constraining membrane during the expansion of the TIPS coated stent provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0044] 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.

[0045] 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.

[0046] In addition, in this application, 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 between 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 this application according to the specific circumstances.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] Figure 1 This is a schematic structural diagram of a TIPS covered stent provided by one embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a TIPS covered stent provided by one embodiment of the present invention after the restraining membrane is unfolded. Figure 3 for Figure 2 The structural schematic diagram shows that the connecting portion of the restraining membrane is connected to the covering membrane segment.

[0051] See also Figure 1This embodiment provides a TIPS covered stent, comprising a proximal covered segment 1, a distal bare segment 2, and a constraining membrane 3. The covered segment 1 comprises a first metal skeleton 11 and a covering 12. The distal end of the first metal skeleton 11 is connected to the proximal end of the bare segment 2. The covering 12 at least covers and is fixed to the outside of the first metal skeleton 11. The constraining membrane 3 covers at least a portion of the covering 12 on the outside of the covering 12.

[0052] 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.

[0053] See also Figure 1 、 Figure 2 The restraining membrane 3 includes a main body 31, a first end located at the proximal end of the main body 31 and a second end located at the distal end of the main body 31, and the first end and / or the second end is provided with a connecting portion 32 for fixed connection with the covering membrane 12, and the dimension of the end of the connecting portion 32 away from the main body 31 in the circumferential direction of the covering membrane segment 1 is smaller than the dimension of the end close to the main body 31 in the circumferential direction of the covering membrane segment 1.

[0054] The TIPS stent graft of this embodiment is used to establish a blood flow channel between the hepatic vein and the portal vein. The graft 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 graft segment 1 at the end of the connecting portion 32 distal to the main body 31 is smaller than the circumferential dimension of the graft segment 1 at the end proximal to the main body 31. This simplifies the securing of 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 graft segment 1 corresponding to the connecting portion 32, making insertion and withdrawal of the binding membrane 3 smoother, reducing the risk of curling of the binding membrane 3, and reducing the likelihood of separation of the binding membrane 3 from the graft 12 or breakage at the connection with the graft 12.

[0055] The first metal skeleton 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 metal skeleton 11 is smaller than the diameter of the distal end. In one example, the first metal skeleton 11 includes multiple first structural units, and the first structural units are spirally distributed along the axial direction of the coating segment 1. In this example, there is no particular restriction on the shape of the first structural units, as long as the first structural units have protrusions 111. Recesses 112 are formed between the first structural units. For example, the first structural units are triangular, semicircular, arc-shaped, etc. In this way, the 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 metal skeleton 11 includes multiple structural components, and the multiple structural components are arranged in intervals along the axial direction of the coating segment 1. Adjacent structural components are connected by the coating 12, or adjacent structural components are connected by connectors. Each structural component includes multiple first structural units arranged circumferentially along the coating segment 1. Similarly, it is sufficient as long as the first structural units have protrusions 111. Recesses 112 are formed between the first structural units. For example, the first structural units may be triangular, semicircular, or arc-shaped. Thus, the first structural units in the structural assembly are sequentially connected to form distal protrusions 111 and proximal recesses 112. The first metal skeleton 11 is made of a biocompatible alloy material with shape memory, such as nickel-titanium alloy.

[0056] The coating 12 is coated on the outside of the first metal skeleton 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. Preferably, the coating 12 is also coated on the inner side of the first metal skeleton 11 to further prevent the liquid in the liver parenchyma from penetrating. Preferably, the proximal shape of the coating 12 matches the proximal shape of the first metal skeleton 11. After the TIPS coated stent is implanted, since the proximal end of the coating 12 matches the proximal shape of the first metal skeleton 11, there will be no insufficiently unfolded coating 12 at the proximal end face of the stent that folds toward the inside of the shunt channel and affects the inner cavity space of the shunt channel.

[0057] This embodiment has no particular limitation on the fixing method of the membrane 12 and the first metal frame 11. For example, the membrane 12 and the first metal frame 11 can be fixed by bonding, suturing, anchoring, sintering, etc. The membrane 12 can be made of PTFE material or ePTFE material.

[0058] 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), causing the binding membrane 3 to undergo plastic deformation, with the radial dimension slightly larger than the second radial dimension. The coating segment 1 expands as the binding membrane 3 radially expands and is re-constrained 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.

[0059] Preferably, the greater the axial distance between the connecting portion 32 and the main portion 31, the smaller the size of the connecting portion 32 in the circumferential direction of the coating segment 1. More preferably, the size of the connecting portion 32 in the circumferential direction of the coating segment 1 decreases in proportion to the axial distance between the connecting portion 32 and the main portion 31. For example, the connecting portion 32 is triangular or trapezoidal when unfolded. More preferably, the size of the connecting portion 32 in the circumferential direction of the coating segment 1 decreases in non-proportional proportion to the axial distance between the connecting portion 32 and the main portion 31. For example, the connecting portion 32 is arc-shaped, sinusoidal, semi-elliptical, or semi-drum-shaped when unfolded. In this way, the connecting portion 32 is smoother when inserted into the sheath or when the sheath is withdrawn.

[0060] 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.

[0061] For further information, see Figure 1 and Figure 8In the axial direction of the coated segment 1, the length of the constraining membrane 3 is less than that of the coating 12, and the constraining membrane 3 is located in the middle of the coated segment 1. That is, there is a distance between the first end of the constraining membrane 3 and the proximal end of the coating, and / or between the second end of the constraining membrane 3 and the distal end of the coating. This distance is preferably 5-10 mm. Preferably, the distance between the first end of the constraining membrane 3 and the proximal end of the coating is not equal to the distance between the second end of the constraining membrane 3 and the distal end of the coating. Thus, when the TIPS coated stent is crimped into the sheath of the delivery device, the proximal end of the coating 12 enters the sheath a distance before the constraining membrane 3 enters. This reduces the initial crimping force required and allows for smoother insertion. After the stent is implanted, blood flow into the coated segment 1 first passes through the distal portion (larger diameter) not covered by the constraining membrane 3, then gradually flows through the portion (smaller diameter) of the constraining membrane 3. This creates a natural blood flow transition and minimizes impact on the stent. When the stent is dilated by balloon, the portion covered by the constraining membrane 3 is primarily expanded. Since a distance not covered by the binding membrane 3 is left at each end of the binding membrane 3, the expansion area of ​​the binding membrane 3 is smaller, and the stent expansion is more convenient.

[0062] See also Figure 2 and Figure 4 The connection portion 32 includes a top region 321 and a connection region 322. The top region 321 is away from the main body 31 and is used to be fixedly connected to the covering 12. The connection region 322 is close to the main body 31 and adjacent to another connection portion 32. The binding membrane 3 is connected to the covering 12 only through a few top regions 321 at both ends, which greatly reduces the process and difficulty of connecting the binding covering 3 and the covering 12, and simplifies the production of the stent. The edge between the top region 321 and the connection region 322 can be straight, in which case the connection portion 32 can be triangular or trapezoidal; the edge between the top region 321 and the connection region 322 can be curved, in which case the connection portion 32 can be arc-shaped, sine-shaped, semi-elliptical, or semi-drum-shaped.

[0063] In this embodiment, the portion of the connection portion 32 provided at the first end that is away from the main body is located on the distal side of the first structural unit that is axially closest to the main body, and the portion of the connection portion 32 provided at the second end that is away from the main body 31 is located on the proximal side of the first structural unit that is axially closest to the main body. 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 at the first end of the first metal skeleton 11 first contacts the lumen of the sheath, and the connection portion 32 provided at the first end is located on the distal side of the first structural unit, which reduces the probability of contact with the lumen of the sheath, further avoiding the occurrence of curling. Similarly, when the sheath is withdrawn, the lumen of the sheath also first contacts the first structural unit located distal to the connection portion 32 at the second end of the first metal skeleton 11, and the connection portion 32 provided at the second end is located on the proximal side of the first structural unit, which reduces the probability of contact with the lumen of the sheath, further avoiding the occurrence of curling.

[0064] Furthermore, for the connection portion 32 disposed at the first end, the top region 321 is disposed distally of the recess 112 corresponding to the first structural unit closest in the axial direction, while the connection region 322 is disposed distally of the protrusion 111 adjacent to the recess 112. Here, "adjacent" includes both adjacent to the first structural unit without any separation and adjacent to the first structural unit separated by several separations. For the connection portion 32 disposed at the second end, the top region 321 is disposed proximal to the protrusion 111 corresponding to the first structural unit closest in the axial direction, while the connection region 322 is disposed proximal to the recess 112 adjacent to the protrusion 111.

[0065] Preferably, when the first metal skeleton 11 comprises a plurality of structural components, the plurality of structural components are arranged at intervals along the axial direction of the coating segment 1, and each structural component comprises a plurality of first structural units arranged circumferentially along the coating segment 1, the connecting portion 32 is correspondingly arranged circumferentially at the first end and / or the second end of the main body 31 and located on the same plane perpendicular to the axis. Figure 2 As shown, after the binding membrane 3 is unfolded, the connecting parts 32 at the first and second ends of the binding membrane 3 are flushly arranged in the axial direction perpendicular to the covering segment 1. In other embodiments, when the first structural unit is directly distributed in a spiral along the axial direction of the covering segment 1, the connecting parts 32 can be arranged in a spiral shape accordingly. In this case, when the binding membrane 3 is unfolded, the multiple connecting parts 32 can be gradually arranged axially to the left or right from top to bottom. Figure 4 As shown, at the first end of the restraining membrane 3, a plurality of connecting portions 32 are gradually arranged axially to the right from top to bottom.

[0066] Furthermore, when the first end is provided with a connection portion 32, the top region 321 of the connection portion 32 is located distally of the recess 112, and the connection region 322 of the connection portion 32 is located distally of the protrusion 111 adjacent to the recess 112 adjacent to the top region 321. When the second end is provided with a connection portion 32, the top region 321 of the connection portion 32 is located proximally of the protrusion 111, and the connection region 322 of the connection portion 32 is located proximally of the recess 112 adjacent to the protrusion 111 adjacent to the top region 321. In this embodiment, the arrangement of the top region 321 and the connection region 322 of the connection portion 32 respectively corresponds to the arrangement of the adjacent recess 112 and protrusion 111 of the first metal skeleton. When the connection portion 32 of the first end is connected to the coating 12, the connection portion 32 of 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 sheathing smoother. Similarly, 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, making sheath withdrawal smoother. Simply connecting the top region 321 of the connecting portion 32 to the covering 12 distal to the recess 112 facilitates connection between the binding membrane 3 and the covering 12. Similarly, when connecting the connecting portion 32 at the second end to the covering 12, simply connecting the top region 321 of the connecting portion 32 to the covering 12 proximal to the protrusion 111 facilitates connection between the binding membrane 3 and the covering 12.

[0067] Specifically, see Figure 2 and Figure 3 In this embodiment, each structural component of the first metal skeleton 11 has six first structural units, each of which is triangular in shape. These six units are sequentially connected to form a structure with six recesses 112 and six protrusions 111. At the proximal end of the restraining membrane 3, there are six connecting portions 32, each with a triangular outer contour. 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 the structural component's recess 112, 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 of the restraining membrane 3 are similarly configured.

[0068] Preferably, 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 section 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.

[0069] Figure 9 for Figure 2 The force diagram of the circumferential direction of the binding membrane during the expansion process is shown below. In combination with the force analysis of the binding membrane 3 during the expansion of the TIPS coated stent, the principle of how the connecting portion 32 in the above embodiment can avoid breaking at the connection with the coating 12 and separating from the coating 12 at the connection is described in detail. For the convenience of explanation, Figure 9 The middle bounding membrane is in the expanded state.

[0070] See also Figure 1 and Figure 9 When the diameter of the TIPS coated stent is expanded, the bundle coating 3 is subjected to a radial outward force (i.e., a force perpendicular to the Figure 9 The force is also affected by the deformation of the binding membrane 3 itself (which may be elastic or plastic). This force is on the circumferential surface (on the Figure 9 The circumferential force on a point is positively correlated with the length change, especially in the initial stage, where it is close to a proportional relationship, i.e., the greater the length change, the greater the corresponding force.

[0071] like Figure 9 As shown, at any point A on the main body 31 of the diaphragm 3 (within the dashed box), the circumferential tension Fa exerted on the diaphragm 3 is measured, and the expanded length La of the diaphragm 3 (i.e., the circumference of the diaphragm 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 diaphragm 3 at point A is proportional to ΔD / D1, i.e., Fa∝ΔLa / La = ΔD / D1.

[0072] 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 triangular connection 321, ΣLb = 0 and ΣLb / La = 0. Therefore, the circumferential tensile force Fb exerted on the restraining 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. This region secures the binding membrane 3 to the stent coating 12, preventing the binding membrane 3 from separating from the stent coating 12 and preventing the binding membrane 3 from tearing.

[0073] Figure 4 This is a schematic structural diagram of a TIPS covered stent provided by another embodiment of the present invention after the restraining membrane is unfolded. Figure 5 for Figure 4 The diagram shows the structure of the tie film connected to the covering film segment. Figure 4 and Figure 5 The present embodiment differs from the above-described embodiment in that the first metal skeleton 11 comprises multiple first structural units, which are arranged in a spiral along the axial direction of the coating segment 1. Each turn of the first metal skeleton 11 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 portion 32 at the first end of the restraining membrane 3 is also triangular in shape, with six connecting portions 32 arranged in a spiral pattern. When a connecting portion 32 is provided at the first end, the top region 321 of the connecting portion 32 is located distally to the depression 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 to the adjacent protrusion 111. Similarly, when a connecting portion 32 is provided at the second end, the top region 321 of the connecting portion 32 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 adjacent depression 112.

[0074] In an alternative embodiment, when a connecting portion 32 is provided at the first end, the recess 112 adjacent to the top region 321 of the connecting portion 32 is not adjacent to the protrusion 111 adjacent to the connection region 322 of the connecting portion 32; when a connecting portion 32 is provided at the second end, the protrusion 111 adjacent to the top region 321 of the connecting portion 32 is not adjacent to the recess 112 adjacent to the connection region 322 of the connecting portion 32. In this case, the number of connecting portions 32 does not correspond to the number of first structural units.

[0075] Figure 6 This is a schematic structural diagram of a TIPS covered stent provided by another embodiment of the present invention after the restraining membrane is deployed. Figure 7 for Figure 6 The structural diagram of the binding membrane connected to the covering membrane section is shown. Figure 8 For the Figure 6 Schematic diagram of the structure of the TIPS covered stent with the tethered membrane shown. Figure 6-8 In this embodiment, each structural component of the first metal skeleton 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, the top region 321 of the first connecting portion 32 is located distally of the recess 112 of the first structural unit closest in the axial direction, i.e., distally of the second recess 112 in the figure, while the connecting region 322 is located distally of the third protrusion 111. Here, the second recess 112 and the third protrusion 111 are not adjacent. The connecting portion 32 at the second end can also be arranged in a similar manner. In this embodiment, the number of connecting portions 32 is less than the number of first structural units, simplifying the manufacturing process for connecting the restraining membrane 3 to the covering segment 1.

[0076] Figure 10 A schematic diagram of the wrinkle structure on the restraining membrane of a TIPS covered stent provided in one embodiment of the present invention. Figure 11 This is a schematic diagram of the process of the wrinkle structure change on the binding membrane when the TIPS coated stent is expanded according to one embodiment of the present invention. Figure 10 and Figure 11In the above embodiment, the main body 31 further includes an axially distributed pleated structure 33. The pleated structure 33 is used to prevent the tethering membrane 3 from axially shortening during expansion (i.e., when the coated segment 1 changes from the first radial dimension to the second radial dimension). Generally, when the TIPS coated stent is expanded, the inherent force of the tethering membrane 3 causes the tethering membrane 3 to shorten in the axial direction, thereby causing the coated segment 1 to undergo undesirable axial shortening. In this embodiment, the pleated structure 33 offsets the effect of this inherent force and prevents the axial shortening of the tethering membrane 3. As the coated segment 1 expands, the radial dimension of the tethering membrane 3 increases, and the pleated structure 33 gradually decreases until it disappears. The cross-section of the pleated structure 33 (here, the cross-section along the axial direction) can be irregular or regular, preferably a trapezoid, rectangle, or triangle. The specific dimensions of the pleated structure 33 are not particularly limited in this embodiment, as long as they can prevent the tethering membrane 3 from axially shortening.

[0077] The bare segment 2 of this embodiment includes a second metal structure 21. The second metal structure 21 is cylindrical. In this embodiment, the radial dimension of at least part of the second metal structure 21 is larger than that of the first metal structure. For example, the radial dimension of the proximal end (i.e., the end connected to the coated segment 1) of the second metal structure 21 is equal to the radial dimension of the first metal structure, but smaller than the radial dimension of the distal end (the end away from the coating). In this way, when the TIPS coated stent is impacted by blood, the bare segment 2 located in the portal vein helps to mitigate the impact of blood flow on the stent, causing the TIPS coated stent to move. Similarly, the second metal structure 21 is an alloy material with shape memory function, such as nickel-titanium alloy. The second metal structure 21 includes at least second structural units, and multiple second structural units are distributed axially along the bare segment 2. This embodiment has no particular limitation on the shape of the second structural units. For example, the second structural units are wavy, and adjacent second structural units are intertwined and connected to each other, that is, the crest of one second structural unit is intertwined and connected with the trough of another adjacent second structural unit.

[0078] See also Figure 1 In the above embodiment, a developing structure 4 is provided at both the proximal and distal ends of the coating section 1. For example, a developing ring is provided at the proximal end of the coating section 1, and a developing belt is provided at the junction of the coating section 1 and the bare section 2.

[0079] 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 metal skeleton and a 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 an external force so that the coated segment is restrained in the second radial dimension. The TIPS coated stent can achieve the purpose of stent diameter change; 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 are provided with a connecting portion for fixedly connecting to the coating. The restraining membrane is fixedly connected to the coating via the connecting portions located at the first and second ends of the main body. The fixing method between the binding membrane and the coating is simpler and faster; the size of the end of the connection part away from the main body in the circumferential direction of the coating segment is smaller than the size of the end of the connection part close to the main body in the circumferential direction of the coating segment, and the force required when pressing and gripping the coating segment is smaller, and it is easier to press and grip; when the TIPS coated stent is inserted into the sheath, under the condition of a certain space in the sheath cavity, the resistance of the binding membrane when pressing into the sheath or retracting the sheath is reduced, and the probability of curling of the binding membrane is also reduced; the connection part of the first end and the second end of the binding membrane is subjected to less force at the connection with the coating, and when the TIPS coated stent changes diameter and expands, the connection part of the first end and the second end of the binding membrane will not separate from the coating, avoiding the connection part of the first end and the second end of the binding membrane at the connection with the coating and separation from the coating.

[0080] 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.

[0081] 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 covered stent, characterized by: It includes a proximal covered segment, a distal bare segment and a restraining membrane, wherein the covered segment includes a first metal skeleton and a covered membrane; The distal end of the first metal skeleton 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 metal skeleton, and the restraining film covers at least a portion of the covering film on the outside of the covering film; 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. 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.

2. The TIPS covered stent according to claim 1, characterized in that: The farther the axial distance between the connecting portion and the main body portion is, the smaller the size of the connecting portion in the circumferential direction of the coating segment is.

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

4. The TIPS covered stent according to claim 1, characterized in that: The connecting portion includes a top area and a connecting area. The top area is away from the main body and is used to be fixedly connected to the covering film. The connecting area is close to the main body and adjacent to the other connecting portion.

5. The TIPS covered stent according to claim 1, characterized in that: The first metal skeleton includes a plurality of first structural units, at least some of which are connected in sequence; When the first end is provided with the connecting portion, the portion of the connecting portion away from the main body is located on the far side of the first structural unit that is closest in the axial direction; When the second end is provided with the connecting portion, the portion of the connecting portion away from the main body is located on the proximal side of the first structural unit that is axially closest.

6. The TIPS covered stent according to claim 5, characterized in that: 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, 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 adjacent to the other connecting portion; For the connecting portion provided at the first end, the top region is provided on the distal side of the recess corresponding to the first structural unit closest in the axial direction, and the connecting region is provided on the distal side of the protrusion near the recess; For the connecting portion arranged at the second end, the top region is arranged on the proximal side of the protrusion corresponding to the first structural unit closest in the axial direction, and the connecting region is arranged on the proximal side of the recess near the protrusion.

7. The TIPS covered stent according to claim 6, characterized in that: 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.

8. The TIPS covered stent according to claim 7, characterized in that: The shape of the connecting portion matches the shape of the first structural unit, and the number of the connecting portions is the same as the number of the first structural units.

9. The TIPS covered stent according to claim 6, characterized in that: When the first end is provided with the connecting portion, the depression adjacent to the top region of the connecting portion is not adjacent to the protrusion adjacent to the connecting region of the connecting portion; When the second end is provided with the connecting portion, the protrusion adjacent to the top region of the connecting portion is not adjacent to the recess adjacent to the connecting region of the connecting portion.

10. The TIPS covered stent according to any one of claims 5 to 9, characterized in that: The first structural units are distributed in a spiral along the axial direction of the coating segment; or, The first metal skeleton includes a plurality of structural components, the plurality of structural components are arranged at intervals along the axial direction of the coating segment, and adjacent structural components are connected by the coating, or adjacent structural components are connected by connecting pieces; Each of the structural components includes a plurality of first structural units distributed along the circumference of the coating segment.

11. The TIPS covered stent according to claim 10, characterized in that: When 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 the same plane perpendicular to the axial direction, the connecting portions are arranged circumferentially and are located in the same plane perpendicular to the axial direction.

12. The TIPS covered stent according to claim 1, characterized in that: 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.

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