A covered stent and a method for manufacturing the same

Abstract

The application discloses a kind of film-covered stent and its preparation method in the technical field of medical devices, including polymer film tube, metal stent and polymer fixing belt;The outer circumferential surface of the polymer film tube is provided with annular or spiral wave-shaped groove along the axial direction, the groove is formed by heat pressing on the surface of the polymer film tube according to the self-defined path, the metal stent is wave-shaped woven structure with wave crest and wave trough structure, and the inner diameter size of the metal stent in the natural expansion state is between the inner diameter and the outer diameter of the polymer film tube;The metal stent is at least partially embedded in the groove to realize the pre-fixing of the two;The polymer fixing belt is annular or spiral band structure and is wrapped around the outside of the polymer film tube, part of its inner wall is in contact with the outer surface of the metal stent, and the other part covers and contacts the outer surface of the polymer film tube.The application reduces the risk of stent and film tube separation and the risk of postoperative restenosis, and improves the use safety of the film-covered stent.

Description

TECHNICAL FIELD

[0001] The present application relates to a covered stent and a preparation method thereof, and belongs to the technical field of medical devices. BACKGROUND

[0002] The covered stent is a medical device that can be used for vascular repair, especially for vascular diseases that cause vascular stenosis and occlusion, and can restore blood supply by supporting the lesion site. At present, the commonly used covered stent in clinical practice is mainly composed of a metal stent and a covering material. The metal stent is usually made of biocompatible metal materials such as medical stainless steel and nickel-titanium alloy, and is formed into a specific tubular structure through laser cutting or braiding process. After being implanted into the human body, it can be radially expanded to provide support force through self-expansion or balloon expansion. The covering layer is usually made of high polymer materials such as expanded polytetrafluoroethylene (ePTFE), polyurethane (TPU), silicone, and polyester (PET), which are combined with the metal stent through sewing, bonding or laminating, etc. to form a closed tubular channel to prevent body fluid from leaking into the lesion area. The existing covered stent can be delivered by a delivery system for minimally invasive implantation. Clinical tests have shown that the covered stent can provide good support force, significantly reduce the risk of vascular rupture, and has the advantages of small trauma and rapid recovery.

[0003] In the prior art, the metal stent and the covering material are not firmly combined, and are prone to separation. Moreover, due to the specific braided structure of the stent and the small contact area of the covering material, the combination of the stent and the covering material by wrapping with a fixing belt or point bonding may cause relative displacement or even separation of the stent and the covering material under the condition of stent expansion or blood flow fluctuation. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a covered stent and a preparation method thereof, which solves the problems of poor combination of the metal stent and the membrane in the prior art and inaccurate positioning of the metal stent relative to the membrane during the compounding process, reduces the risk of separation of the stent and the membrane tube and the risk of restenosis after surgery, and improves the safety and effectiveness of the covered stent.

[0005] To achieve the above-mentioned purposes, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a covered stent, comprising a polymer membrane tube, a metal stent and a polymer fixing belt; the outer circumferential surface of the polymer membrane tube is provided with annular or spiral wave-shaped grooves at intervals along the axial direction, the grooves are formed by hot pressing on the surface of the polymer membrane tube according to a self-defined path, the metal stent has a wave-shaped woven structure with a wave crest and a wave trough structure, and the inner diameter of the metal stent in a natural expansion state is between the inner diameter and the outer diameter of the polymer membrane tube; the metal stent is at least partially embedded in the grooves to achieve the pre-fixing of the two; the polymer fixing belt has a ring or spiral belt structure and is wrapped around the outside of the polymer membrane tube, a part of the inner wall thereof contacts the outer surface of the metal stent, and another part covers and contacts the outer surface of the polymer membrane tube, and the polymer fixing belt is fixed with the metal stent and the polymer membrane tube by heating and compounding.

[0007] Further, the cross section of the groove includes any one of an arc shape, a semicircular shape, a triangular shape, a square shape, and a trapezoidal shape, and a combination of any one of the square shape, the semicircular shape, the triangular shape, and the trapezoidal shape.

[0008] Further, the shape of the groove is consistent with the woven shape of the metal stent, and the woven shape includes a number of periodic units, a wave crest height, a wave trough depth, and a wave crest spacing.

[0009] Further, the metal stent has an uninterrupted structure or a plurality of metal ring combination structures, and is made of a medical metal, including one or more of nickel-titanium alloy, cobalt-chromium alloy, and stainless steel.

[0010] Further, the material of the polymer membrane tube is one or more of expanded polytetrafluoroethylene and porous polyurethane, and the porosity is 20%-95%; and the material of the polymer fixing belt is one or more of expanded polytetrafluoroethylene and fluorinated ethylene propylene copolymer.

[0011] In a second aspect, the present application provides a preparation method of a covered stent, for preparing the covered stent as described above, comprising:

[0012] A cylindrical mandrel with an outer diameter matching the inner diameter of the polymer membrane tube is selected, and the polymer membrane tube is sleeved along the axis of the cylindrical mandrel to ensure that the surface of the polymer membrane tube is wrinkle-free;

[0013] The two ends of the polymer membrane tube are fixed on the mandrel by a locking device, and after the assembly of the "mandrel-polymer membrane tube" is placed horizontally in the clamping position of the self-defined path groove processing equipment and clamped, the clamping position is the two ends of the mandrel;

[0014] Select the heating head, set the temperature according to the material of the polymer film tube, set the depth, moving track and moving speed according to the shape of the metal support, set the starting position 3-5mm away from the edge of the locking device at one end of the polymer film tube, and make grooves on the polymer film tube according to the set program;

[0015] After the grooves are made, the "mandrel-polymer film tube" assembly is removed, the metal support is sleeved in the conveying pipe with an inner diameter greater than the natural expansion state of the metal support, the conveying pipe is transported along the assembly axis to the corresponding groove position of the polymer film tube, the metal support is removed and placed in the groove, and the position is adjusted to ensure close fit with the groove;

[0016] The polymer fixing belt is wound around the wave rod position outside the metal support to form a "mandrel-polymer film tube-metal support-polymer fixing belt" assembly, the wave crest and wave trough of the metal support are exposed, and the spacing of the polymer fixing belt is consistent with the spacing of the metal support;

[0017] The "mandrel-polymer film tube-metal support-polymer fixing belt" assembly is heated and compounded;

[0018] After the heating and compounding are completed, the mandrel is removed and the ends of the coated support are cut, and the manufacturing is completed.

[0019] Further, the outer diameter of the mandrel is 0.01-0.1mm smaller than the inner diameter of the polymer film tube, and the mandrel material is polytetrafluoroethylene or stainless steel; after the locking device is fixed, the clamping position of the two ends of the mandrel is greater than 1cm.

[0020] Further, the shape of the tip of the heating head includes a sphere, a cone, a cylinder or a circular truncated cone.

[0021] Further, the temperature of the heating head is set to be 5-40℃ lower than the melting point of the single or mixed material; the depth of the heating head is set to be 25-1000μm; the moving track of the heating head is consistent with the woven shape of the metal support, and the axial spacing of adjacent grooves is consistent with the spacing of the periodic units of the metal support.

[0022] Further, the inner diameter of the conveying pipe is 0.1-1mm larger than the outer diameter of the polymer film tube; the temperature of the heating and compounding is 220℃-350℃, and the heating time is 5-15min.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] The stent is partially or completely embedded in the polymer film tube, which slows down the ups and downs of the surface of the covered stent, and ensures that the stent is combined with the polymer film tube according to the pre-woven shape. The pre-fixing of the groove to the metal stent and the double fixing of the polymer fixing belt make the structure of the covered stent more stable, and reduce the risk of separation of the stent and the film tube; the improved flatness of the surface of the covered stent can reduce the stimulation to the inner wall of the blood vessel, and reduce the risk of postoperative restenosis; finally, embedding the stent in the film during the compounding process can significantly improve the positioning deviation of the metal stent relative to the film, improve the positioning accuracy, prevent the metal stent from deviating or twisting during the compounding process, so that the metal stent can provide uniform and controllable radial support force during use, and ensure the safety of the covered stent. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application, explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0026] Figure 1 A high polymer film tube and its groove of a covered stent provided for the first embodiment of the application;

[0027] Figure 2 A high polymer film tube and its groove of a covered stent provided for the first embodiment of the application;

[0028] Figure 3 A covered stent with a stent completely embedded type covered stent cross section provided for the first embodiment of the application;

[0029] Figure 4 A covered stent with a stent partially embedded type covered stent cross section provided for the second embodiment of the application;

[0030] Figure 5 A self-defined path groove processing equipment of a covered stent provided for the third embodiment of the application;

[0031] Figure 6 Different heating heads and corresponding groove shapes of a covered stent provided for the third embodiment of the application.

[0032] In the figure: 1, polymer film tube; 11, groove; 2, metal stent; 3, polymer fixing belt; 4, heating head; 5, circumferential sliding module; 6, axial sliding module; 7, clamping position; 8, locking device; 9, operation interface. DETAILED DESCRIPTION

[0033] The application will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0034] The following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical terms used in the application have the same meanings as generally understood by those skilled in the art. The terms used in the application are only for the purpose of describing the specific embodiments and are not intended to limit the exemplary embodiments according to the application.

[0035] Embodiment one:

[0036] Please refer to Figure 1 , Figure 2 and Figure 3 , the embodiment provides a covered stent, which comprises a polymer film tube 1, a metal stent 2 and a polymer fixing belt 3. The outer circumferential surface of the polymer film tube 1 is provided with annular wavy grooves 11 in the axial direction. The cross section of the groove 11 is a combination of square and semicircle. The shape of the groove 11 is completely consistent with the woven shape of the metal stent 2. The polymer fixing belt 3 is an annular belt structure and is located at the outermost side. A part of the inner wall thereof is in contact with the outer surface of the metal stent 2, and the other part covers and contacts the outer surface of the polymer film tube 1. The metal stent 2 of the embodiment is completely embedded in the groove 11 of the polymer film tube 1.

[0037] The material of the polymer film tube 1 is one or more of expanded polytetrafluoroethylene and porous polyurethane. The embodiment preferably uses expanded polytetrafluoroethylene. The porosity is 20%-90%. The embodiment preferably has a porosity of 50%-90%. The material of the metal stent 2 is nickel-titanium alloy. The material of the polymer fixing belt 3 is a mixed material of expanded polytetrafluoroethylene and fluorinated ethylene propylene copolymer.

[0038] The metal stent 2 provides support for the covered stent. The polymer fixing belt 3 is used to connect the metal stent and the polymer film tube. The metal stent 2 is completely embedded in the polymer film tube 1, so that the technical effect of completely flat outer surface of the polymer film tube 1 can be achieved. The polymer fixing belt 3 can be fixed by closely adhering to the surface of the polymer film tube 1. The metal stent 2 is accurately positioned and has no displacement and damage risk in the groove 11.

[0039] Embodiment two:

[0040] Please refer to Figure 4The covered stent comprises a polymer film tube 1, a metal stent 2 and a polymer fixing belt 3. The outer circumferential surface of the polymer film tube 1 is provided with annular wave-shaped grooves 11 at intervals along the axial direction. The cross section of the groove 11 is arc-shaped. The metal stent 2 is embedded in the groove 11 and completely adheres to the groove 11. The polymer fixing belt 3 is located at the outermost side. A part of the inner wall of the polymer fixing belt 3 is in contact with the outer surface of the metal stent 2, and another part of the inner wall of the polymer fixing belt 3 covers and contacts the outer surface of the polymer film tube 1. In the embodiment, the metal stent 2 is partially embedded in the groove 11 of the polymer film tube 1. The material of the polymer film tube 1 is one or more of expanded polytetrafluoroethylene and porous polyurethane. In the embodiment, the expanded polytetrafluoroethylene is preferably used. The porosity is 20%-90%. In the embodiment, the porosity is preferably 20%-50%. The material of the metal stent 2 is nickel-titanium alloy. The material of the polymer fixing belt 3 is a mixed material of expanded polytetrafluoroethylene and fluorinated ethylene propylene copolymer.

[0041] The metal stent 2 is partially embedded in the polymer film tube, which can improve the concave-convex form of the surface of the covered stent, improve the flatness of the outer surface of the covered stent, and make the fixing effect of the polymer fixing belt 3 on the metal stent 2 and the polymer film tube 1 better. When the grooves 11 are combined, the grooves 11 can constrain the metal stent 2, prevent the metal stent 2 from deforming and shifting, and ensure the safety of the covered stent.

[0042] It should be noted that the metal stent 2 of the first embodiment and the second embodiment is partially or completely embedded, the cross-sectional shape of the groove 11, the porosity of the polymer film tube 1, and the materials of the metal stent 2 and the polymer film tube 1 can be changed and combined at will within the scope defined in the claims of the present application, which does not affect the technical scope defined in the claims of the present application and does not affect the beneficial effects of the present application.

[0043] Embodiment three:

[0044] For reference, Figure 5 The present application also provides a preparation method of the covered stent, which can prepare the covered stent of the first embodiment and the second embodiment, and comprises the following steps:

[0045] (1) Prepare a formed polymer film tube 1 and a metal stent 2. The polymer film tube 1 is made of expanded polytetrafluoroethylene and has a porosity of 50%, an inner diameter of 5 mm and an outer diameter of 5.2 mm. The metal stent 2 is a continuous metal wire woven into a shape, which has an inner diameter of 5.1 mm in a natural expanded state, a cycle unit number of 7, a wave peak height of 1 mm, a wave valley depth of 1 mm and a wave peak spacing of 2.28 mm.

[0046] (2) Put the polymer membrane tube 1 into the stainless steel mandrel with a diameter of 4.95 mm, check the polymer membrane tube to ensure that there are no wrinkles; fix the two ends of the polymer membrane tube 1 on the mandrel with the locking device 8, after fixing, there is a clamping position of 1.5 cm at both ends of the mandrel, place the assembled polymer membrane tube 1 and mandrel horizontally in the clamping position 7 of the self-defined path groove machining equipment and control the pneumatic device on the operation interface 9 to clamp it.

[0047] (3) Select the spherical heating head 4, set the temperature to 320°C, set the depth to 50 pm according to the shape of the metal stent 2, the moving trajectory is consistent with the shape of the metal braid, the moving speed is 1 mm / s, take the edge of the locking device 8 at one end of the polymer membrane tube 1 as the reference, and set the starting position 3 mm away from the reference line. After setting the program, start, adjust the heating head 4 to be embedded in the polymer membrane tube 1 to the specified depth by the circumferential sliding module 5, move the axial sliding module 6 left and right and rotate the clamping position 7 to make the heating head 4 heat and press out the groove 11 shape at different positions of the polymer membrane tube 1.

[0048] (4) After completing the production of the groove 11, take out the polymer membrane tube 1 with the groove 11 and the mandrel from the equipment, put the metal stent 2 into the conveying pipe with an inner diameter of 5.3 mm and an outer diameter of 5.6 mm, the conveying pipe is made of stainless steel, the conveying pipe is transported along the axis of the polymer membrane tube 1 to the corresponding groove 11 position of the polymer membrane tube 1, the metal stent 2 is taken out by manual control and placed in the groove 11, the position is adjusted to ensure that it fits tightly with the groove 11, the conveying pipe is gradually withdrawn until the metal stent 2 is completely separated from the pipe and placed in the groove 11. During the placement of the stent, the metal stent 2 will temporarily expand to increase the inner diameter, but due to its elastic deformation, it can match the groove 11 shape and be partially embedded.

[0049] (5) Wrap the polymer fixing belt 3 around the wave rod position outside the metal stent 2, keep the wave crest and wave trough exposed, and the spacing of the polymer fixing belt 3 is consistent with the spacing of the metal stent 2. Keeping the wave crest and wave trough exposed can avoid constraints on the expansion and bending deformation of the stent during use, and the metal stent can adjust the bending angle of the covered stent by flexible bending to accurately match the complex environment of the blood vessel in the body.

[0050] (6) Place the above assembled polymer membrane tube 1-metal stent 2-polymer fixing belt 3 as a whole in an oven at 325°C for 9 minutes, cool it down, remove the mandrel and cut the covered stent at both ends to obtain the covered stent finished product.

[0051] Please refer to Figure 6, using different shapes of heating head 4 can leave different grooves 11 on the surface of the polymer film tube, using conical heating head 4 can make triangular cross-section grooves 11 on the surface of the polymer film tube 1; using spherical heating head 4 can leave the groove 11 with arc-shaped, semicircular cross-section on the surface of the polymer film tube 1; using the heating head 4 of circular truncated cone can prepare the groove 11 with trapezoidal cross-section on the surface of the polymer film tube 1, using the heating head 4 of cylinder can prepare the groove 11 with square cross-section on the surface of the polymer film tube 1. At the same time, it can be inferred that if the heating head 4 is completely inserted into the polymer film tube 1 to work, it can form grooves 11 with any combination of square and triangular, semicircular, trapezoidal cross-section.

[0052] The triangular and trapezoidal grooves 11 are complete or partial inverted triangular on the cross-section of the polymer film tube 1, which can be adapted to a variety of different diameter braided wires to achieve partial embedding, but the bottom is not completely matched with the braided wire; the arc-shaped and semicircular grooves 11 can ensure that the grooves 11 are closely matched with the metal stent 2, but the single size heating head 4 can only match one diameter of braided wire; the square groove 11 can adapt to square braided wire to achieve close fit, the metal stent 2 made of square braided wire has higher bending strength and stronger radial stiffness than that of circular braided wire under the same cross-sectional area, but the circular braided wire has better flexibility, surface smoothness and fatigue resistance. Therefore, according to the specific needs of preparing the covered stent, the appropriate heating head 4 can be selected to prepare grooves 11 with different shapes.

[0053] It should be noted that in order to further accurately control the forming quality of the groove 11, the controller PLC or industrial PC reads the material parameters from the database during the processing of the groove 11, then obtains the design parameters and preliminary process parameters from the user interface, and then calculates the required unit line energy density J l based on the energy control formula of thermodynamics. The controller uses the formula P=J l ×v to inversely calculate the real-time power P required by the heating head, and then sends instructions to the power module of the heating head 4 to accurately set the output power to this value. The calculation formula of the required unit line energy density J l is as follows:

[0054]

[0055] In the formula: J l is the required unit line energy density, which represents the total energy required by the heating head 4 to move every millimeter along the predetermined path; k m is the thermal conductivity of the polymer film tube material; ρ m is the density of the polymer film tube 1 material; C m is the specific heat capacity of the polymer film tube 1 material; T pThe heating head temperature, set to the target processing temperature to soften or viscous flow the polymer material to form the groove 11, is typically slightly higher than the material's softening point; T a Ambient temperature, i.e., the initial temperature of the processing environment, is usually room temperature; A c P represents the cross-sectional area of ​​the target groove. c α is the effective hot-pressing perimeter of the contact surface between the heating head 4 and the material; α is the material-specific heat loss coefficient; v max v is the maximum stable moving speed of the equipment; v is the set moving speed of the heating head.

[0056] The above-described solution ensures high repeatability of groove dimensions (depth, width) and shape by precisely controlling the input energy per unit length, avoiding grooves that are too deep, too shallow, or distorted due to power or speed fluctuations. The calculation formula incorporates a speed compensation factor, enabling the system to automatically adapt to changes in processing speed and achieve speed-power linkage optimization. This significantly reduces the difficulty for operators in adjusting process parameters, improving production efficiency and process stability. When changing the polymer membrane material, only the material parameters need to be updated to quickly determine the optimal process window, shortening the development cycle of new products. By controlling energy rather than simply temperature or time, the input heat can be managed more precisely, effectively preventing polymer degradation and charring caused by localized overheating, thus ensuring the long-term biocompatibility and mechanical properties of the coated scaffold.

[0057] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative and not exhaustive. All modifications within the scope of this invention or its equivalents are included in this invention.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a covered scaffold, characterized in that, include: Select a cylindrical mandrel with an outer diameter that matches the inner diameter of the polymer membrane tube (1), and insert the polymer membrane tube (1) along the axis of the cylindrical mandrel to ensure that there are no wrinkles on the surface of the polymer membrane tube (1). The two ends of the polymer membrane tube (1) are fixed to the mandrel using the locking device (8). After assembling into the "mandrel-polymer membrane tube (1)" assembly, it is placed horizontally in the clamping position (7) of the custom path groove processing equipment and clamped. The clamping position is the two ends of the mandrel. Select a heating head (4), set the temperature according to the material of the polymer membrane tube (1), set the depth, movement trajectory and movement speed according to the shape of the metal support (2), set the starting position 3-5mm from the edge of the locking device (8) at one end of the polymer membrane tube (1), and make a groove (11) on the polymer membrane tube (1) according to the set program. The required unit linear energy density J of the groove (11) is calculated by the controller during processing. l Then, combined with the set moving speed v of the heating head (4), the formula P=J is used. l ×v calculates the real-time power P required to output by the heating head (4), and the required unit linear energy density J. l The calculation formula is: ； In the formula: J l k is the required unit linear energy density. m The thermal conductivity of the polymer membrane tube material; ρ m C is the density of the polymer membrane tube (1) material; m The specific heat capacity of the polymer membrane tube (1) material; T p The target processing temperature; T a Ambient temperature; A c P represents the cross-sectional area of ​​the target groove. c The effective hot-pressing perimeter of the contact surface between the heating head (4) and the material; α is the material-specific heat loss coefficient; v max v is the maximum stable moving speed of the equipment; v is the set moving speed of the heating head (4); After the groove (11) is made, remove the "core rod-polymer membrane tube (1)" assembly, put the metal bracket (2) into the delivery tube which is larger than its inner diameter under natural expansion, and transport the delivery tube along the axis of the assembly to the corresponding groove (11) position of the polymer membrane tube (1). Remove the metal bracket (2) and place it in the groove (11), and adjust the position to ensure that it fits tightly with the groove (11). The polymer fixing tape (3) is wrapped around the wave rod position on the outside of the metal support (2) to assemble it into a "core rod-polymer membrane tube (1)-metal support (2)-polymer fixing tape (3)" assembly. The peaks and valleys of the metal support (2) are kept exposed, and the spacing of the polymer fixing tape (3) is consistent with the spacing of the metal support (2). The "core rod-polymer membrane tube (1)-metal support (2)-polymer fixing tape (3)" assembly was heat-composite; After the heating and lamination are completed, the mandrel is removed and the two ends of the film-coated bracket are cut to complete the fabrication.

2. The method for preparing the covered scaffold according to claim 1, characterized in that, The outer diameter of the core rod is 0.01-0.1 mm smaller than the inner diameter of the polymer membrane tube (1), and the core rod is made of polytetrafluoroethylene or stainless steel; after the locking device (8) is fixed, the clamping positions at both ends of the core rod are greater than 1 cm.

3. The method for preparing the covered scaffold according to claim 1, characterized in that, The tip shape of the heating head (4) includes spherical, conical, cylindrical or frustum-shaped.

4. The method for preparing the covered scaffold according to claim 1, characterized in that, The depth of the heating head (4) is set to 25-1000μm; the movement trajectory of the heating head (4) is consistent with the weaving shape of the metal bracket (2), and the axial spacing of adjacent grooves (11) is consistent with the periodic unit spacing of the metal bracket (2).

5. The method for preparing the covered scaffold according to claim 1, characterized in that, The inner diameter of the delivery pipe is 0.1-1 mm larger than the outer diameter of the polymer membrane tube (1); the heating and compounding temperature is 220℃-270℃ and the heating time is 5-10 min.

6. A covered stent, characterized in that, The membrane scaffold is prepared by any one of the preparation methods described in claims 1-5, comprising a polymer membrane tube (1), a metal scaffold (2), and a polymer fixing band (3); the outer circumferential surface of the polymer membrane tube (1) is provided with annular wavy grooves (11) spaced along the axial direction, the grooves (11) are formed by hot pressing on the surface of the polymer membrane tube (1) according to a custom path, the metal scaffold (2) is a wavy braided structure with crests and troughs, and the inner diameter of the metal scaffold (2) in the natural expansion state is between the inner diameter and the outer diameter of the polymer membrane tube (1); the metal scaffold (2) is at least partially embedded in the grooves (11) to achieve pre-fixation of both; the polymer fixing band (3) is an annular band structure and is wrapped around the outside of the polymer membrane tube (1), a part of its inner wall contacts the outer surface of the metal scaffold (2), and the other part covers and contacts the outer surface of the polymer membrane tube (1), the polymer fixing band (3) achieves dual fixation with the metal scaffold (2) and the polymer membrane tube (1) by heating and bonding.

7. The covered stent according to claim 6, characterized in that, The cross-section of the groove (11) includes any one of the following: arc shape, semi-circle, triangle, square, trapezoid, and any combination of square with semi-circle, triangle, and trapezoid.

8. The covered stent according to claim 6, characterized in that, The shape of the groove (11) is consistent with the weave shape of the metal bracket, which includes the number of periodic units, peak height, valley depth and peak spacing.

9. The covered stent according to claim 6, characterized in that, The metal support (2) is an integrally woven, uninterrupted structure or a combination of multiple metal rings. The material is a metal with elasticity and shape memory, including one or more of nickel-titanium alloy and cobalt-chromium alloy.

10. The covered scaffold according to claim 6, characterized in that, The polymer membrane tube (1) is made of one or more of expanded polytetrafluoroethylene and porous polyurethane, and the porosity is 20%-95%; the polymer fixing tape (3) is made of one or more of expanded polytetrafluoroethylene and fluorinated ethylene propylene copolymer.

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