Covered stent

Abstract

The application belongs to the technical field of medical devices and relates to a covered stent. The covered stent comprises a lumen stent, an expansion stent and a covered component. The expansion stent and the lumen stent are both hollow tubular structures with open ends, the expansion stent is arranged in the lumen stent, the length of the expansion stent in the axial direction is less than the length of the lumen stent in the axial direction. The covered component comprises a first covered layer, a second covered layer and a third covered layer. The first covered layer is arranged on the lumen stent, the third covered layer is arranged on the expansion stent, and the second covered layer is connected to the first covered layer and the third covered layer, so that the diameter of the expansion stent can be adjusted by the balloon. By using the covered stent provided in the application, the radial support force is provided by the lumen stent to maintain the patency of the blood flow in the lumen stent, and the diameter can be adjusted by the secondary surgery by using the expansion stent, so that the blood flow pressure in the covered stent is adjusted.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a covered stent. Background Technology

[0002] Transjugular intrahepatic portosystemic shunt (TIPS) is an effective treatment for esophageal variceal bleeding and refractory ascites caused by portal hypertension. Guided by digital subtraction angiography (DSA), TIPS establishes a portal-systemic shunt via puncture through the jugular vein, creating a shunt between the intrahepatic vein and the portal vein. This significantly reduces portal venous resistance structurally and is a key measure for lowering portal venous pressure in patients with cirrhosis. It is characterized by minimal invasiveness, high safety, broad indications, and significant short-term clinical efficacy, and is widely used in clinical practice.

[0003] Currently, TIPS stents used in clinical practice are mainly divided into two categories: balloon-expandable stents and self-expanding stents.

[0004] Balloon-expandable stents are stents pre-loaded onto a balloon catheter, made of medical-grade stainless steel and cobalt-chromium alloy. Delivered to the lesion site along with a balloon, the balloon is inflated to release the stent, and the expanded stent opens the diseased blood vessel.

[0005] After implantation, balloon-expandable stents offer poor support for the channel, greatly increasing the likelihood of subsequent lumen collapse. Furthermore, due to the constraints imposed by external tissues, re-expansion is ineffective, and adjusting the diameter is difficult.

[0006] Self-expanding stents are ultra-elastic stents made from thin-walled nickel-titanium superelastic alloy tubes through laser precision engraving. They are delivered to the lesion via a gripping delivery catheter, and after release from fixation, they self-expand to allow blood flow and provide support to the lesion site.

[0007] After a self-expanding stent is implanted in the human body, it is difficult to adjust its diameter again during balloon expansion.

[0008] In clinical practice, after a period of time following the TIPS procedure to implant a stent, such as 24 hours later, at least one pressure measurement is required to determine whether there is a pressure gradient between the portal vein and the systemic venous circulation due to the shunt, and thus whether the stent diameter needs to be adjusted.

[0009] When portal vein pressure has decreased but not yet reached the reference range, it is necessary to increase the diameter of the channel to further reduce portal vein pressure. However, it is difficult to adjust the diameter of the stent after implantation, which can lead to complications in patients. Summary of the Invention

[0010] To address the technical challenge of adjusting the diameter of a covered stent after implantation during transjugular intrahepatic portal vein shunt (THL), this application provides a covered stent comprising: a luminal stent, an expandable stent, and a covered assembly.

[0011] Both the expansion support and the lumen support are hollow tubular structures with openings at both ends. The expansion support is disposed inside the lumen support, and the axial length of the expansion support is less than the axial length of the lumen support.

[0012] The coating assembly includes a first coating layer, a second coating layer, and a third coating layer;

[0013] The first coating layer is disposed on the lumen stent, the third coating layer is disposed on the dilatation stent, and the second coating layer is connected to the first coating layer and the third coating layer respectively, which enables the balloon to adjust the diameter of the dilatation stent.

[0014] Optionally, the length of the line connecting the contact point of the first coating layer and the second coating layer to the distal end of the first coating layer is L1, and the length of the outer periphery of the second coating layer is L2, where L1 > L2.

[0015] Optionally, when the expansion stent is configured in a compressed state, the third coating layer binds the periphery of the expansion stent.

[0016] Optionally, the third coating layer is made of expanded polytetrafluoroethylene material in an unsintered state.

[0017] Optionally, the coating assembly further includes a first support member disposed on the second coating layer, with both ends of the first support member connected to the first coating layer and the third coating layer, respectively.

[0018] Optionally, the two ends of the first support member are fixedly connected to the expansion bracket and the lumen bracket, respectively; the first support member is a curved rod structure or a straight rod structure.

[0019] Optionally, the expansion bracket includes at least two connecting rings, and multiple connecting parts are fixedly connected between adjacent connecting rings. The connecting parts are straight rod-shaped structures or curved rod-shaped structures.

[0020] Optionally, the first support member is disposed at the middle of the axial length of the expansion bracket, and the first support member is configured to be symmetrical with respect to the central axis of the expansion bracket.

[0021] Optionally, the coating assembly further includes a fourth coating layer, which is connected to the third coating layer and the first coating layer respectively; the fourth coating layer and the second coating layer protrude from the outer periphery of the expansion bracket; or, the fourth coating layer and the second coating layer are recessed from the outer periphery of the expansion bracket.

[0022] Optionally, the coating assembly further includes a second support member disposed on the fourth coating layer, with both ends of the second support member connected to the first coating layer and the third coating layer, respectively.

[0023] Optionally, the second coating layer and the fourth coating layer are respectively provided with through holes, and the two through holes are provided correspondingly.

[0024] Optionally, a channel is also provided between the two through holes for blood circulation.

[0025] Optionally, the covered stent further includes a recessed structure disposed between the lumen stent and the expansion stent, the recessed structure being connected to both the lumen stent and the expansion stent, the middle portion of the recessed structure being suspended, and the recessed structure being able to adjust the diameter of the expansion stent.

[0026] The technical solutions provided in this application have the following advantages compared with the prior art:

[0027] The covered stent provided in this application includes a luminal stent, an expandable stent, and a covering assembly. The expandable stent is housed within the luminal stent, and the covering assembly covers both the luminal stent and the expandable stent, together forming a blood flow channel. Blood flows in from the proximal end of the luminal stent, passes through the expandable stent, and then flows out from the distal end of the luminal stent.

[0028] The covered assembly comprises three layers: a first layer is placed on the luminal stent, a third layer is placed on the dilatational stent, and a second layer connects the first and third layers. This allows the luminal stent to provide radial support to the liver parenchyma between the portal and jugular veins, thereby establishing a blood flow pathway. When changes in blood flow pressure are needed, a secondary procedure using a balloon can adjust the diameter of the dilatational stent, thereby reducing portal vein pressure in patients with cirrhosis. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a covered scaffold provided in Embodiment 1 of this application;

[0032] Figure 2 for Figure 1 A cross-sectional view along the AA direction;

[0033] Figure 3 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 1 of this application;

[0034] Figure 4 This is a schematic diagram of the structure of the lumen stent provided in Embodiment 1 of this application;

[0035] Figure 5 This is a schematic diagram of the structure of the coating component provided in Embodiment 1 of this application;

[0036] Figure 6 This is a schematic diagram of the first coating layer structure provided in Embodiment 1 of this application;

[0037] Figure 7 This is a schematic diagram of the third coating layer structure provided in Embodiment 1 of this application;

[0038] Figure 8 This is a schematic diagram of the second coating layer structure provided in Embodiment 1 of this application;

[0039] Figure 9 and Figure 10 This is a schematic diagram of the structure of the covered stent ejected from the balloon according to Embodiment 1 of this application;

[0040] Figure 11 for Figure 10 Cross-sectional view along the BB direction;

[0041] Figure 12 for Figure 11 Cross-sectional view of balloon inserted into covered stent along the BB direction;

[0042] Figure 13 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 2 of this application;

[0043] Figure 14 for Figure 13 Cross-sectional view along the CC direction;

[0044] Figure 15 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 3 of this application;

[0045] Figure 16 for Figure 15 Cross-sectional view along the DD direction;

[0046] Figures 17 to 20 This is a schematic diagram of the structure of the first support member provided in Embodiment 3 of this application;

[0047] Figure 21 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 3 of this application;

[0048] Figure 22 for Figure 21 Cross-sectional view along the EE direction;

[0049] Figure 23 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 4 of this application;

[0050] Figure 24 for Figure 23 Cross-sectional view along the FF direction;

[0051] Figures 25 to 26 This is a schematic diagram of the structure of the connecting part provided in Embodiment 4 of this application;

[0052] Figures 27 to 28 This is a schematic diagram of the structure of the expansion stent provided in Embodiment 4 of this application;

[0053] Figure 29 Here are structural schematic diagrams of the covered stents provided in five embodiments of this application;

[0054] Figure 30 for Figure 29 Cross-sectional view along the GG direction;

[0055] Figure 31 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 5 of this application;

[0056] Figure 32 for Figure 31 Cross-sectional view along the HH direction;

[0057] Figure 33 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment Six of this application;

[0058] Figure 34 for Figure 33 Cross-sectional view along direction II;

[0059] Figure 35 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment Six of this application;

[0060] Figure 36 for Figure 35 Cross-sectional view along the JJ direction;

[0061] Figure 37 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment Six of this application;

[0062] Figure 38 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 7 of this application;

[0063] Figure 39 for Figure 38 Cross-sectional view along the KK direction;

[0064] Figure 40 This is a schematic diagram of the structure of the film-coated stent provided in Embodiment 7 of this application;

[0065] Figure 41 This is a schematic diagram of the operation of the film-coated bracket provided in Embodiment 7 of this application.

[0066] Figure label:

[0067] 100. Covered stent; 110. Lumen stent; 120. Expanded stent; 130. Covered assembly; 131. First covered layer; 132. Second covered layer; 133. Third covered layer;

[0068] 200, Covered stent; 210, Lumen stent; 220, Expanded stent; 230, Covered assembly; 231, First covered layer; 232, Second covered layer; 233, Third covered layer;

[0069] 300, Covered stent; 310, Lumen stent; 320, Expanded stent; 330, Covered assembly; 331, First covered layer; 332, Second covered layer; 333, Third covered layer; 334, First support member;

[0070] 400, Covered stent; 410, Lumen stent; 420, Expanded stent; 421, Connecting part; 430, Covered assembly; 431, First covered layer; 432, Second covered layer; 433, Third covered layer; 434, First support member;

[0071] 500, Covered stent; 510, Lumen stent; 520, Expanded stent; 530, Covered assembly; 531, First covered layer; 532, Second covered layer; 533, Third covered layer; 534, Fourth covered layer;

[0072] 600, Covered stent; 610, Lumen stent; 620, Expanded stent; 630, Covered assembly; 631, First covered layer; 632, Second covered layer; 633, Third covered layer; 634, Fourth covered layer; 635, First support member; 636, Second support member; 637, Through hole;

[0073] 700, Covered stent; 710, Lumen stent; 720, Expanded stent; 730, Covered assembly; 731, First covered layer; 732, Second covered layer; 733, Third covered layer; 734, Recessed structure; 734a, First recess; 734b, Second recess; 734c, Third recess; 735, Fifth covered layer;

[0074] 1. Balloon; 2. Blood vessel. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0076] In the description of this invention, it should be noted that, in the field of interventional medical devices, the proximal end refers to the end closer to the operator, while the distal end refers to the end farther from the operator; the axial direction refers to the direction parallel to the line connecting the center of the distal end and the center of the proximal end of the medical device. The above definitions are for ease of expression only and should not be construed as limiting the invention.

[0077] Example 1:

[0078] refer to Figures 1 to 12 This application provides a covered stent 100, including a lumen stent 110, an expansion stent 120, and a covered assembly 130. The expansion stent 120 is disposed within the lumen stent 110. Both the expansion stent 120 and the lumen stent 110 are hollow tubular structures with openings at both ends. The axial length of the expansion stent 120 is less than the axial length of the lumen stent 110. The covered assembly 130 includes a first covered layer 131, a second covered layer 132, and a third covered layer 133. The first covered layer 131 is disposed on the lumen stent 110, the third covered layer 133 is disposed on the expansion stent 120, and the second covered layer 132 connects the first covered layer 131 and the third covered layer 133, enabling the balloon 1 to adjust the diameter of the expansion stent 120.

[0079] By placing the dilatation stent 120 within the luminal stent 110, and covering the luminal stent 110 and the dilatation stent 120 respectively, a blood flow channel is formed together. Blood flows in from the proximal end of the luminal stent 110, flows through the dilatation stent 120, and flows out from the distal end of the luminal stent 110.

[0080] refer to Figures 6 to 8 The covered assembly 130 includes three covered layers: a first covered layer 131 is disposed on the luminal stent 110, a third covered layer 133 is disposed on the dilatation stent 120, and the two ends of the second covered layer 132 are respectively connected to the first covered layer 131 and the third covered layer 133. In this way, the luminal stent 110 can provide radial support to support the liver parenchyma between the portal vein and the jugular vein, thereby establishing a blood flow channel. When it is necessary to change the blood flow pressure, the diameter of the dilatation stent 120 can be adjusted through a secondary surgery, thereby reducing the portal vein pressure in patients with cirrhosis.

[0081] Since the expansion stent 120 is housed within the lumen stent 110, the diameter of the first coating layer 131 is larger than the diameter of the second coating layer 132, and the diameter of the second coating layer 132 is larger than the diameter of the third coating layer 133. At the junction of the first coating layer 131 and the second coating layer 132, the diameters of the first coating layer 131 and the second coating layer 132 are substantially equal. At the junction of the second coating layer 132 and the third coating layer 133, the diameters of the second coating layer 132 and the third coating layer 133 are substantially equal.

[0082] Continue to refer to Figures 1 to 2 To ensure that the expandable stent 120 remains continuously within the lumen stent 110, a line connecting the contact point of the first covering layer 131 and the second covering layer 132 to the distal end of the first covering layer 131 is provided with a length of L1, and the outer peripheral length of the second covering layer 132 is L2, where L1 > L2. This prevents the expandable stent 120 from moving distally under the impact of blood flow from the proximal end to the distal end of the lumen stent 110, thus avoiding the outer peripheral edge of the expandable stent 120 protruding beyond the outer peripheral edge of the lumen stent 110, causing the expandable stent 120 to collide with human tissue and cause damage.

[0083] refer to Figure 1 The luminal stent 110 includes multiple spaced-apart coils, each coil comprising a crest, a trough, and a straight rod connecting the crests and troughs. After the luminal stent 110 is implanted into the human body, the multiple coils can self-expand and firmly attach to the liver parenchyma. Adjacent coils may or may not be connected.

[0084] The expandable stent 120 also includes multiple spaced-apart corrugations, each corrugation comprising a crest, a trough, and a straight bar connecting the crest and trough. The outer contour of the corrugations has a wavy structure, which facilitates compression and expansion, giving the overall structure of the covered stent 100 ductility. Adjacent corrugations may or may not be connected.

[0085] The corrugated coil is made of a metal material with good biocompatibility and elasticity, such as stainless steel, nickel-titanium alloy, or cobalt-chromium alloy. In the actual fabrication of the lumen stent 110 or expansion stent 120, the corrugated coil is shaped by braiding nickel-titanium wire or cutting nickel-titanium tube. Of course, the corrugated coil can also be made by braiding or cutting stainless steel wire.

[0086] The first coating layer 131 wraps around both the inner wall and outer periphery of the lumen stent 110, and then heat-presses it to completely fix the first coating layer 131 and the lumen stent 110 together. Similarly, the third coating layer 133 wraps around both the inner wall and outer periphery of the expansion stent 120, and then heat-presses it to completely fix the third coating layer 133 and the expansion stent 120 together.

[0087] The first coating layer 131, the second coating layer 132, and the third coating layer 133 are all made of thin film materials with good biocompatibility, such as polyethylene terephthalate (PET) and expanded polytetrafluoroethylene (e-PTFE).

[0088] refer to Figures 9 to 10 In actual clinical use, the covered stent 100 is mounted on the balloon 1, and the balloon 1 is entirely mounted in the sheath. Due to the good extensibility of the covered stent 100, the balloon 1 is compressed when mounted on it. When the balloon 1 is released from the sheath, the luminal stent 110 within the covered stent 100 springs open normally, increasing its diameter, while the dilatation stent 120 does not spring open.

[0089] refer to Figures 11 to 12 A covered stent 100 is placed in the liver parenchyma between the jugular vein and portal vein to establish a blood flow channel. The diameter of the expanded stent 120 is then pre-inflated using balloon 1. A pressure measurement is performed 24 hours later to confirm the existence of a pressure gradient. The diameter of the expanded stent 120 is then further expanded as needed. Because both the expanded stent 120 and the third covered layer 133 have good extensibility, the blood pressure flowing through the covered stent 100 is improved after the diameter of the expanded stent 120 is changed, thus regulating blood pressure.

[0090] In Embodiment 1, the perimeter of the third coating layer 133 is greater than the perimeter of the expansion stent 120 when it is in a compressed state. The perimeter of the expansion stent 120 is the perimeter of a cross section perpendicular to the axial direction, which is approximately circular.

[0091] When balloon 1 is used for expansion in Embodiment 1, the third covering layer 133 is no longer extended, only the expansion stent 120 is extended.

[0092] Example 2:

[0093] refer to Figures 13 to 14 This application provides a second embodiment of a covered stent 200. The difference between the covered stent 200 of the second embodiment and the covered stent 100 of the first embodiment is that the assembly method of the expansion stent 220 and the third covered layer 233 is different. In the second embodiment, when the balloon 1 is used for expansion, the third covered layer 233 and the expansion stent 220 expand synchronously.

[0094] The covered stent 200 includes a lumen stent 210, an expansion stent 220, and a covered assembly 230. The covered assembly 230 includes three covered layers: a first covered layer 231 is disposed on the lumen stent 210, a third covered layer 233 is disposed on the expansion stent 220, and the two ends of a second covered layer 232 are respectively connected to the first covered layer 231 and the third covered layer 233.

[0095] When the expandable stent 220 is in the compressed state, the third covering layer 233 adheres to the inner and outer sides of the expandable stent 220. The third covering layer 233 constricts the periphery of the expandable stent 220. After the third covering layer 233 is heat-pressed and shaped, its surface is flat and tightly adheres to the periphery of the expandable stent 220. Thus, when the covered stent 200 is released, the expandable stent 220 expands synchronously with the luminal stent 210 under the action of the balloon, and the surface of the third covering layer 233 can remain flat, which is beneficial to maintaining blood flow stability. This avoids a sharp increase in blood flow channels caused by the third covering layer 233 expanding along with the expandable stent 220, which could affect the blood flow stability of the covered stent 200.

[0096] The third coating layer 233 is made of polytetrafluoroethylene (PTFE) with good ductility, or it can be made of expanded PTFE. The third coating layer 233 can be made of sintered PTFE or unsintered PTFE. Because unsintered PTFE has unbent fibrils, which can elongate by more than 40% before breakage, unsintered PTFE has better compliance and ductility than sintered PTFE, thus improving the ductility of the third coating layer 233.

[0097] Example 3:

[0098] refer to Figures 15 to 22 This application provides a film-coated support 300 in Embodiment 3. The difference between the film-coated support 300 in Embodiment 3 and the film-coated support 100 in Embodiment 1 is that the film-coated component 330 further includes a first support member 334.

[0099] The covered stent 300 includes a lumen stent 310, an expansion stent 320, and a covered assembly 330. The covered assembly 330 includes three covered layers. The first covered layer 331 is disposed on the lumen stent 310, the third covered layer 333 is disposed on the expansion stent 320, and the two ends of the second covered layer 332 are respectively connected to the first covered layer 331 and the third covered layer 333.

[0100] refer to Figure 16 The covering assembly 330 also includes a first support member 334, which is disposed on the second covering layer 332. The two ends of the first support member 334 are connected to the first covering layer 331 and the third covering layer 333, respectively. The first support member 334 provides stable support to the dilatation stent 320, thereby maintaining the position of the dilatation stent 320 under the impact of blood flow, preventing the dilatation stent 320 from swinging within the lumen stent 310, and reducing the occurrence of blood flow instability. Alternatively, the first support member 334 may be partially or not connected to the covering assembly 330.

[0101] refer to Figure 17 The two ends of the first support member 334 are fixedly connected to the expansion bracket 320 and the lumen bracket 310, respectively. Specifically, the first support member 334 includes at least three connecting members connected in sequence, namely the first connecting member 334a, the second connecting member 334b, and the third connecting member 334c.

[0102] The first connector 334a and the third connector 334c are fixedly mounted on the lumen stent 310 and the expansion stent 320, respectively, and the second connector 334b ​​is mounted on the second coating layer 332. Alternatively, the two ends of the first support member 334 can be rigidly connected to the expansion stent 320 and the lumen stent 310, respectively, by welding or riveting, thereby making the connection more stable. The first support member 334 can provide stable support to the expansion stent 320, thereby maintaining the stability of the expansion stent 320's position and preventing the expansion stent 320 from swinging inside the lumen stent 310, thus avoiding unstable blood flow.

[0103] The first support member 334 is made of a material with good biocompatibility and a certain elastic modulus. This allows the first support member 334 to maintain its original shape under the impact of blood flow. For example, the first support member 334 can be made of stainless steel, nickel-titanium alloy, cobalt-chromium alloy, or iron-based materials.

[0104] The first support member 334 can be a curved rod-like structure or a straight rod-like structure. The first support member 334 can be designed as a straight rod-like structure as a whole, which is better at resisting the impact of blood flow and is less prone to breakage.

[0105] refer to Figure 18 The positional relationship between the first support member 334 and the expansion bracket 320 and the lumen bracket 310 can be varied. For example... Figure 18 As shown in (a), the first support member 334 can be disposed in the same radial direction as the expansion bracket 320 and the lumen bracket 310; as Figure 18 As shown in (b), the first support 334 can also be disposed in different radial directions of the expansion bracket 320 and the lumen bracket 310; or, as shown in (b) Figure 18 As shown in (c), the first support member 334 can also be arranged in a certain arc direction between the expansion bracket 320 and the lumen bracket 310.

[0106] refer to Figure 19 The first support member 334 has a curved spatial structure and is fixed to the expansion bracket 320. The first support member 334 includes a curved section that bends in multiple different directions, such as inward or outward.

[0107] To ensure that the first support member 334 can provide stable support to the expandable stent 320, the first support member 334 is configured as a curved rod structure, which includes two curved sections and three connecting sections, with one connecting section connected to each end of the curved section. This allows the first support member 334 to adapt to the blood flow environment within the luminal stent 310, ensuring stable support of the expandable stent 320. The curved rod structure can also provide axial and radial support forces, better maintaining the stability of the expandable stent 320 within the human body.

[0108] refer to Figure 20 The first support member 334 can also be a three-dimensional curved structure, with one end connected to the expansion bracket 320 and the other end connected to the lumen bracket 310.

[0109] refer to Figure 22 Alternatively, the first support member 334 can be positioned at the midpoint of the axial length of the expandable stent 320, and the first support member 334 can be configured to be symmetrical with respect to the central axis of the expandable stent 320. This further improves the implantation stability of the covered stent 300. The central axis of the expandable stent 320 is the centerline along the axial direction of the expandable stent 320.

[0110] Example 4:

[0111] refer to Figures 23 to 28This application provides a covered stent 400 in embodiment four. The difference between the covered stent 400 in embodiment four and the covered stent 300 in embodiment three is that the structure of the expansion stent 420 is different.

[0112] The covered stent 400 includes a lumen stent 410, an expansion stent 420, and a covered assembly 430. The covered assembly 430 includes three covered layers. The first covered layer 431 is disposed on the lumen stent 410, the third covered layer 433 is disposed on the expansion stent 420, and the two ends of the second covered layer 432 are respectively connected to the first covered layer 431 and the third covered layer 433.

[0113] refer to Figure 25 and Figure 26 The expansion bracket 420 includes at least two connecting rings, and a plurality of connecting parts 421 are fixedly connected between adjacent two connecting rings. The connecting parts 421 are straight rod column structures or curved column structures.

[0114] refer to Figure 27 and Figure 28 The two connecting rings are closed-loop wave coil structures, and a connecting part 421 is fixedly provided between two adjacent connecting rings. The connecting part 421 is made of a material with good elasticity and biocompatibility.

[0115] The first support member 434 has a closed-loop coil structure, and its diameter can expand under the expansion of the balloon. The first support member 434 is made of a material with good ductility and biocompatibility. The expansion stent 420 and the first support member 434 form a rigid connection, and part of the structure of the expansion stent 420 extends into the second coating layer 432.

[0116] Both the expandable stent 420 and the first support member 434 adopt a closed-loop wave coil structure, which allows both the expandable stent 420 and the first support member 434 to maintain a good shape. Furthermore, after being expanded by a balloon, the covered stent 400 can continue to maintain a stable shape, which helps ensure the stability of the covered stent 400 within the human body.

[0117] Example 5:

[0118] refer to Figures 29 to 32 This application provides a film-coated support 500 in embodiment five. The difference between the film-coated support 500 in embodiment five and the film-coated support 100 in embodiment one is that the film-coated component 530 further includes a fourth film layer 534.

[0119] The covered stent 500 includes a lumen stent 510, an expansion stent 520, and a covered assembly 530. The covered assembly 530 also includes a fourth covered layer 534, which is connected to the third covered layer 533 and the first covered layer 531, respectively.

[0120] The fourth coating layer 534 is disposed at the proximal end of the expansion stent 520, and the third coating layer 533 is disposed at the distal end of the expansion stent 520. The fourth coating layer 534 can support the proximal end of the expansion stent 520, and the third coating layer 533 can support the distal end of the expansion stent 520, maintaining the morphological stability of the expansion stent 520.

[0121] refer to Figure 30 Furthermore, a fourth covering layer 534 and a second covering layer 532 can be provided protruding from the outer periphery of the expandable stent 520. The fourth covering layer 534 protrudes from the outer periphery of the expandable stent 520, facilitating blood flow from the inner wall of the expandable stent 520. The second covering layer 532 also protrudes from the outer periphery of the expandable stent 520, thus forming a symmetrical structure along the radial direction of the covered stent 500. This enhances the supporting effect of the covering assembly 530 on the expandable stent 520 and reduces the swaying and displacement of the expandable stent 520.

[0122] refer to Figure 32 Alternatively, a fourth coating layer 534 and a second coating layer 532 can be recessed into the outer periphery of the expansion bracket 520. The ends of both the fourth coating layer 534 and the second coating layer 532 are connected to the outer periphery of the expansion bracket 520, with the fourth coating layer 534 recessed towards the proximal end of the coated bracket 500 and the second coating layer 532 recessed towards the distal end of the coated bracket 500.

[0123] Example 6:

[0124] refer to Figures 33 to 37 This application provides a film-coated support 600 in Embodiment Six. The difference between the film-coated support 600 in Embodiment Six and the film-coated support 500 in Embodiment Five is that the film-coated assembly 630 further includes a second support member 636.

[0125] The covered stent 600 includes a lumen stent 610, an expansion stent 620, and a covered assembly 630. The covered assembly 630 includes four covered layers. The first covered layer 631 is disposed on the lumen stent 610, the third covered layer 633 is disposed on the expansion stent 620, the two ends of the second covered layer 632 are respectively connected to the first covered layer 631 and the third covered layer 633, and the two ends of the fourth covered layer 634 are respectively connected to the third covered layer 633 and the first covered layer 631.

[0126] The coating assembly 630 includes a first support member 635 and a second support member 636. The second support member 636 is disposed on the fourth coating layer 634, and its two ends are connected to the first coating layer 631 and the third coating layer 633, respectively.

[0127] A second support member 636 is provided at the proximal end of the expansion stent 620, and a first support member 635 is provided at the distal end of the expansion stent 620. The first support member 635 and the second support member 636 support and fix the two ends of the expansion stent 620, making the two ends of the expansion stent 620 more stable and improving the positional stability of the expansion stent 620 in the lumen stent 610.

[0128] refer to Figure 36 and Figure 37 The second cover layer 632 and the fourth cover layer 634 are respectively provided with through holes 637, and the two through holes 637 are provided correspondingly. When blood flow impacts the fourth cover layer 634, some blood flow can pass through the through holes 637, reducing the pressure on the fourth cover layer 634 and avoiding excessive pressure that could cause the expandable stent 620 to shift.

[0129] Of course, a conduit can also be provided between the two through holes 637, thus forming a blood channel between them. This more effectively guides blood flow, making the expandable stent 620 more stable and less prone to deformation.

[0130] Example 7:

[0131] refer to Figures 38 to 41 Embodiment 7 of this application provides a film-coated support 700. The difference between the film-coated support 700 of Embodiment 7 and the film-coated support 100 of Embodiment 1 is that the film-coated component 730 further includes a recessed structure 734.

[0132] The covered stent 700 includes a lumen stent 710, an expansion stent 720, and a covered assembly 730. The covered assembly 730 includes three covered layers. The first covered layer 731 is disposed on the lumen stent 710, the third covered layer 733 is disposed on the expansion stent 720, and the two ends of the second covered layer 732 are respectively connected to the first covered layer 731 and the third covered layer 733.

[0133] refer to Figure 39 and Figure 40 The covered stent 700 also includes a recessed structure 734, which is disposed between the lumen stent 710 and the expansion stent 720. The recessed structure 734 is connected to the lumen stent 710 and the expansion stent 720 respectively. The middle part of the recessed structure 734 is suspended. The recessed structure 734 can adjust the diameter of the expansion stent 720.

[0134] The coating assembly 730 includes a fifth coating layer 735, which is connected to a portion of the expansion stent 720. A second coating layer 732 is connected to another portion of the expansion stent 720, thereby forming a recessed structure 734. The recessed structure 734 includes a first recessed portion 734a, a second recessed portion 734b, and a third recessed portion 734c. The first recessed portion 734a and the third recessed portion 734c are respectively connected to the expansion stent 720 and the lumen stent 710, with the middle portion suspended within the recessed structure 734.

[0135] The expandable stent 720 can be adjusted in both directions in diameter. When the covered stent 700 is placed in a blood vessel 2, if it is necessary to reduce the diameter of the expandable stent 720, the concave structure 734 is expanded with a balloon, increasing its length and thus compressing the expandable stent 720, thereby reducing its diameter. Conversely, if it is necessary to increase the diameter of the expandable stent 720, the balloon is adjusted, decreasing the length of the concave structure 734 and thus stretching the expandable stent 720, thereby increasing its diameter. In clinical use, the diameter of the expandable stent 720 can be adjusted bidirectionally according to actual needs, thereby regulating the blood pressure within the covered stent 700. The concave structure 734 is made of a material with good biocompatibility and ductility, such as stainless steel, nickel-titanium alloy, or cobalt-chromium alloy.

[0136] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0137] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A covered stent, characterized in that, include: Lumen stents, expandable stents, and covered assemblies; Both the expansion support and the lumen support are hollow tubular structures with openings at both ends. The expansion support is disposed inside the lumen support, and the axial length of the expansion support is less than the axial length of the lumen support. The coating assembly includes a first coating layer, a second coating layer, and a third coating layer; The first coating layer is disposed on the lumen stent, the third coating layer is disposed on the dilatation stent, and the second coating layer is respectively connected to the first coating layer and the third coating layer, which enables the balloon to adjust the diameter of the dilatation stent; The coating assembly further includes a first support member disposed on the second coating layer, and the two ends of the first support member are respectively connected to the first coating layer and the third coating layer.

2. The covered stent according to claim 1, characterized in that, The length of the line connecting the contact point of the first coating layer and the second coating layer to the far end of the first coating layer is L1, and the length of the outer periphery of the second coating layer is L2, where L1 > L2.

3. The covered stent according to claim 1, characterized in that, When the expansion stent is configured in a compressed state, the third coating layer restrains the periphery of the expansion stent.

4. The covered stent according to claim 3, characterized in that, The third coating layer is made of expanded polytetrafluoroethylene material in an unsintered state.

5. The covered stent according to claim 1, characterized in that, The two ends of the first support member are fixedly connected to the expansion bracket and the lumen bracket, respectively; the first support member is a curved rod-shaped structure or a straight rod-shaped structure.

6. The covered stent according to claim 1, characterized in that, The expansion bracket includes at least two connecting rings, and multiple connecting parts are fixedly connected between adjacent connecting rings. The connecting parts are straight rod-shaped structures or curved rod-shaped structures.

7. The covered stent according to claim 1, characterized in that, The first support member is disposed at the middle of the axial length of the expansion bracket, and the first support member is configured to be symmetrical with respect to the central axis of the expansion bracket.

8. The covered stent according to claim 1, characterized in that, The coating assembly further includes a fourth coating layer, which is connected to the third coating layer and the first coating layer respectively; the fourth coating layer and the second coating layer protrude from the outer periphery of the expansion bracket; or, the fourth coating layer and the second coating layer are recessed from the outer periphery of the expansion bracket.

9. The covered stent according to claim 8, characterized in that, The coating assembly further includes a second support member disposed on the fourth coating layer, with both ends of the second support member connected to the first coating layer and the third coating layer, respectively.

10. The covered stent according to claim 8, characterized in that, The second coating layer and the fourth coating layer are respectively provided with through holes, and the two through holes are provided correspondingly.

11. The covered stent according to claim 10, characterized in that, A channel is also provided between the two through holes to allow for blood flow.

12. The covered stent according to claim 1, characterized in that, The covered stent also includes a recessed structure disposed between the lumen stent and the expansion stent. The recessed structure is connected to both the lumen stent and the expansion stent. The middle part of the recessed structure is suspended. The recessed structure can adjust the diameter of the expansion stent.

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