Covered stent and balloon dilatation covered stent system

Abstract

The invention discloses a covered stent and a balloon dilatation covered stent system, and relates to the technical field of medical instruments.The covered stent comprises a stent body connected through a tubular covering film, and the covered stent has a non-load state with the zero compression diameter and a load state which has the compression rate relative to the non-load state and is used for supporting blood vessels to recover blood flow; when the compression ratio of the covered stent is 10%, the numerical range of the radial supporting force of the covered stent is 2.0 N / mm-6. 0N / mm. The balloon dilatation covered stent system comprises an elastic pipe sleeve, a balloon, a mandrel and a covered stent, the covered stent, the elastic pipe sleeve, the balloon and the mandrel are sequentially arranged from outside to inside in a sleeving mode, and the two ends of the balloon are sealed with the mandrel; the near end of the elastic tube sleeve is fixedly connected with the mandrel or the near end of the balloon; and the far end of the elastic tube sleeve movably sleeves the balloon. The covered stent can provide moderate support for blood vessels, and the problems of lumen restenosis and stent collapse after an existing covered stent is implanted can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a covered stent and a balloon-expandable covered stent system. Background Art

[0002] A covered stent includes a metal stent and a special membranous material coated on the metal stent, and is a medical device used to treat stenosis or obstructive lesions in various parts of the body. Among them, a peripheral vascular covered stent is a medical device used to treat peripheral arterial diseases (such as stenosis, aneurysm or rupture). Currently, there are problems of excessive or insufficient radial supporting force of the covered stent on blood vessels. After 90 days of implantation of the covered stent, obvious vascular stenosis or stent collapse often occurs, and the vascular stenosis rate reaches 17.4%. Summary of the Invention

[0003] The object of the present invention is to provide a covered stent and a balloon-expandable covered stent system to solve the problems existing in the above-mentioned prior art, and be able to provide appropriate support for blood vessels, and effectively improve the problems of restenosis of the lumen and stent collapse after implantation of the existing covered stent.

[0004] To achieve the above object, the present invention provides the following solutions: The present invention provides a covered stent, including a stent body connected by a tubular covering. The covered stent has a non-loaded state with a zero compression diameter, and a loaded state with a compression ratio relative to the non-loaded state for supporting blood vessels to restore blood flow; when the compression ratio of the covered stent is 10%, the numerical range of the radial supporting force of the covered stent is 2.0 N / mm - 6.0 N / mm.

[0005] Preferably, when the compression ratio of the covered stent is 10%, the numerical range of the radial supporting force of the covered stent is 3.0 N / mm - 4.5 N / mm.

[0006] Preferably, at the starting moment when the covered stent is deployed in the blood vessel lumen in the loaded state, the cross-sectional area of the hollow channel of the covered stent is the immediate cross-sectional area; when the covered stent is deployed in the blood vessel lumen and maintained for 90 days, the cross-sectional area of the hollow channel of the covered stent is the first cross-sectional area, and the ratio of the average value of the first cross-sectional area of the covered stent to the average value of the immediate cross-sectional area of the covered stent is greater than 0.7. Further, when the covered stent is deployed in the blood vessel lumen and maintained for 90 days, the ratio of the average value of the first cross-sectional area of the covered stent to the average value of the immediate cross-sectional area of the covered stent is greater than 0.85.

[0007] Preferably, the stent body is an alloy stent; the alloy material components of the stent body include cobalt, titanium and boron.

[0008] Preferably, the material of the stent body is MP35N nickel-cobalt alloy.

[0009] Preferably, the stent body includes a plurality of annular stents longitudinally spaced along the tubular film; the tubular film has a microscopic morphology of a filamentous structure arranged in an oriented manner, and the force on at least part of the annular stents can be transmitted to adjacent annular stents through the filamentous structure of the tubular film.

[0010] Preferably, the tubular film at least includes an inner film layer and an outer film layer, and the stent body is fixedly connected between the inner film layer and the outer film layer; the inner film layer and the outer film layer have different microscopic morphologies.

[0011] Preferably, the inner film layer has a microscopic morphology of a filamentous structure arranged in an oriented manner; the outer film layer has a microscopic morphology of a filamentous structure, and the filamentous structure of the outer film layer is shorter than that of the inner film layer.

[0012] Preferably, the filamentous structure of the film between two adjacent annular stents extends longitudinally along the tubular film.

[0013] Preferably, both ends of the filamentous structure of at least part of the tubular film are respectively connected to two annular stents.

[0014] Preferably, a plurality of filamentous structures of the tubular film between two annular stents are arranged circumferentially along the film stent.

[0015] Preferably, each annular stent is cut from an alloy pipe; each annular stent has a first load diameter equal to the diameter of the alloy pipe; when the annular stent is in the first load diameter state, the film stent has a first load state; the film stent has a delivery state of being sleeved on the outer surface of a non-inflated balloon; the ratio of the longitudinal length value of the film stent in the first load state to the longitudinal length value of the film stent in the delivery state is greater than 0.95; when the film stent is in the first load state, part of the tubular film is stretched by the annular stent without elastic deformation.

[0016] Preferably, each annular stent also has a second load diameter greater than the diameter of the alloy pipe; part of the tubular film can be stretched by the annular stent in the second load diameter state and produce elastic deformation.

[0017] The present invention also provides a balloon-expandable covered stent system, comprising an elastic tube sleeve, a balloon, a mandrel, and the covered stent as described above. The covered stent, the elastic tube sleeve, the balloon, and the mandrel are sequentially sleeved from outside to inside; both ends of the balloon are hermetically and fixedly connected to the mandrel; the proximal end of the elastic tube sleeve is fixedly connected to the mandrel, or the proximal end of the elastic tube sleeve is fixedly connected to the proximal end of the balloon; the distal end of the elastic tube sleeve is movably sleeved on the balloon; the radially contracted covered stent is removably sleeved on the elastic tube sleeve.

[0018] Preferably, the balloon-expandable covered stent system can be expanded from an unexpanded state with an unexpanded diameter to an expanded state with an expanded diameter; in the unexpanded state of the balloon-expandable covered stent system, the covered stent is configured to have prestress, or the elastic tube sleeve is configured to have prestress, or the balloon is configured to have prestress.

[0019] Preferably, in the unexpanded state of the covered stent, there are a number of pleated structures formed by prestress and extending longitudinally.

[0020] Preferably, during the expansion process of the balloon-expandable covered stent system, the pleated structures can inhibit the longitudinal shortening of the covered stent.

[0021] Preferably, in the unexpanded state, the balloon has a pillow structure.

[0022] Preferably, in the unexpanded state of the balloon-expandable covered stent system, gas or liquid is pre-stored in the balloon cavity to form the pillow structure with both ends convex relative to the middle.

[0023] Preferably, during the process of the balloon-expandable covered stent system delivering the covered stent into the target blood vessel cavity, the pillow structure of the balloon can inhibit the covered stent from being detached from the balloon-expandable covered stent system.

[0024] The present invention has achieved the following technical effects compared with the prior art: The present invention provides a covered stent and a balloon-expandable covered stent system, comprising a stent body connected by a tubular covering. The covered stent has a non-loaded state with a zero compression diameter, and a loaded state with a compression ratio relative to the non-loaded state for supporting the blood vessel to restore blood flow; when the compression ratio of the covered stent is 10%, the numerical range of the radial support force of the covered stent is 2.0 N / mm - 6.0 N / mm. The covered stent is placed in the blood vessel cavity in the loaded state to support the blood vessel. By setting the radial support force of the covered stent to 2.0 N / mm - 6.0 N / mm, it can provide appropriate support for the blood vessel and effectively improve the problems of lumen restenosis and stent collapse after the implantation of the existing covered stent. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0026] Figure 1 Schematic structural diagram of the covered stent provided for Embodiment 1; Figure 2 Schematic structural diagram of the tubular covered membrane provided for Embodiment 1; Figure 3 Schematic structural diagram of the stent body in the first load diameter state and the crimped state provided for Embodiment 1; Figure 4 Schematic structural diagram of the support monomer of the stent body in the first load diameter state and the second load diameter state provided for Embodiment 1; Figure 5 OCT image view of the covered stent under the load state after being implanted into the blood vessel provided for Embodiment 1; Figure 6 Schematic diagram of the microscopic morphology of the filamentous structure with oriented arrangement of the tubular covered membrane Figure 1 ; Figure 7 Schematic diagram of the microscopic morphology of the filamentous structure with oriented arrangement of the tubular covered membrane Figure 2 ; Figure 8 Schematic diagram of the microscopic morphology of the filamentous structure with non-oriented arrangement of the tubular covered membrane; Figure 9 For the covered stent in the first load diameter state, with a relatively flat tubular covered membrane; Figure 10 Schematic structural diagram of the balloon-expandable covered stent system provided for Embodiment 2; Figure 11 Partial schematic diagram of the balloon-expandable covered stent system configured with prestress; Figure 12 For Figure 11 In, schematic diagram of the pleated structure of the covered stent system in the undeployed state; Figure 13 For Figure 11 In, schematic diagram of the herringbone fold structure of the covered stent system in the undeployed state; Figure 14 Partial schematic diagram of the balloon forming a pillow structure with two ends convex relative to the middle in the undeployed balloon-expandable covered stent system Figure 1 ; Figure 15In the balloon-expandable covered stent system in the unexpanded state, a partial schematic of the balloon forming a pillow structure with both ends bulging relative to the middle Figure 2 ; Figure 16 Schematic structural diagram of a balloon-expandable covered stent delivery system provided by the present invention; Figure 17 Animal experiment images of the covered stent provided in Example 1 Figure 1 ; Figure 18 Animal experiment images of the covered stent provided in Example 1 Figure 2 ; Figure 19 For Figure 17 In the animal experiment, animal experiment images with a commercially available product as the control group Figure 1 ; Figure 20 For Figure 17 In the animal experiment, animal experiment images with a commercially available product as the control group Figure 2 ; Figure 21 Clinical image of the covered stent provided in Example 1; In the figure: 100, covered stent; 1, tubular covering; 101, inner covering layer; 102, outer covering layer; 103, distal end of the covered stent; 110, first load diameter state; 120, load state; 130, crimped state; 140, second load diameter state; 111, relatively flat tubular covering surface; 1300, prestressed fold structure; 1301, fold structure; 1302, chevron fold structure; 2, stent body; 200, annular stent; 210, first annular stent; 220, second annular stent; 230, third annular stent; 240, fourth annular stent; 201, first load diameter support monomer; 202, crimped state support monomer; 203, second load diameter support monomer; 2101, first support monomer of the first annular stent; 2201, first support monomer of the second annular stent; 2202, second support monomer of the second annular stent; 3, elastic tube sleeve; 301, distal end of the elastic tube sleeve; 302, proximal end of the elastic tube sleeve; 4, balloon; 401, distal end of the balloon; 402, proximal end of the balloon; 403, inner wall of the balloon; 404, outer wall of the balloon; 410, distal end of the balloon catheter; 420, tube body of the balloon catheter; 430, proximal end of the balloon catheter; 5, pillow structure. Detailed implementation mode

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "center", "longitudinal", "transverse", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "clockwise", "counterclockwise", etc. are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Further, it should be noted that in the description of the present invention, unless otherwise clearly defined and limited, the terms "set", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] The purpose of the present invention is to provide a covered stent and a balloon-expandable covered stent system to solve the problems existing in the above-mentioned prior art, which can provide appropriate support for blood vessels and effectively improve the problems of restenosis of the lumen and stent collapse after the implantation of the existing covered stent.

[0030] To make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Embodiment 1 As Figures 1 - 21As shown in the figure, this embodiment provides a covered stent 100, which includes a stent body 2 connected by a tubular covering film 1. The covered stent 100 has a non-loaded state with a zero compression diameter (in the non-loaded state, the support monomers of the annular stent 200 are usually diamond-shaped), and a loaded state 120 with a compression ratio relative to the non-loaded state for supporting blood vessels to restore blood flow; when the compression ratio of the covered stent 100 is 10%, the numerical range of the radial support force of the covered stent 100 is 2.0 N / mm - 6.0 N / mm. By setting the radial support force of the covered stent 100 with a compression ratio of 10% to 2.0 N / mm - 6.0 N / mm, when the covered stent 100 is placed in the blood vessel lumen in the loaded state 120 to support the blood vessel, it can provide appropriate support for the blood vessel and effectively improve the problems of in-stent restenosis and stent collapse after the implantation of the existing covered stent 100; as Figures 17 to 20 shown, the implantation experiment on animals verifies that the covered stent 100 has excellent support performance compared with the commercially available ordinary balloon-expandable covered stent; 90 days after implantation, the covered stent 100 has no collapse (see Figure 18 , the DSA and OCT images 90 days after the operation, the overall covered stent 100 and the arrow-pointed part both maintain a relatively complete stent cavity, with a low lumen loss rate and a blood vessel stenosis rate of about 8.6%), and obvious blood vessel stenosis and stent collapse occur in the control group of the commercially available product (see Figure 20 , the DSA and OCT images 90 days after the operation, the overall control group of the commercially available product and the arrow-pointed part show collapse, with a high lumen loss rate and a blood vessel stenosis rate of about 17.4%).

[0032] It should be noted that the zero compression diameter refers to the natural diameter of the covered stent 100 when it is fully released (not compressed or stretched by external force). The test of the radial support force of the covered stent 100 needs to be carried out in accordance with the "YY / T 1660-2019 Radial Load Test Method for Balloon-expandable and Self-expandable Stents", that is, the radial support force of the covered stent 100 with a compression ratio of 10% needs to be tested. The covered stent 100 adopts a design without connection bridges and has good flexibility; the support monomers adopt a diamond ring design, and a structural unit with high radial strength, fatigue resistance and post-dilation performance is obtained through simulation; such a structural unit can show good anti-collapse performance in actual applications and improve the patency performance of blood vessels. The results of animal test studies comparing the covered stent 100 with the already marketed products show that the covered stent 100 has better blood vessel patency and anti-stent collapse performance.

[0033] In some specific embodiments, the diameter of the covered stent 100 is about 10% larger than the diameter of the normal blood vessel near the blood vessel to be supported (the blood vessel at the stenosis site). After being implanted into the blood vessel, the covered stent 100 contacts and is compressed by the normal blood vessel after being released. After the covered stent 100 is released, it supports the blood vessel at the stenosis site under the expansion action of the balloon 4, so that the diameter of the blood vessel at the stenosis site is approximately the same as or the same as that of the normal blood vessel. When the covered stent 100 is placed in the blood vessel for support, the compression ratio is about 10%.

[0034] As a preferred embodiment, when the compression ratio of the covered stent 100 is 10%, the numerical range of the radial supporting force of the covered stent 100 is 3.0 N / mm - 4.5 N / mm.

[0035] In some specific embodiments, at the initial moment when the covered stent 100 is deployed in the blood vessel lumen in the loaded state 120, the cross-sectional area of the hollow cavity of the covered stent 100 is the immediate cross-sectional area; when the covered stent 100 is deployed in the blood vessel lumen and maintained for 90 days, the cross-sectional area of the hollow cavity of the covered stent 100 is the first cross-sectional area. The ratio of the average value of the first cross-sectional area of the covered stent 100 to the average value of the immediate cross-sectional area of the covered stent 100 is greater than 0.7, that is, this embodiment significantly improves the problems of restenosis of the lumen and stent loss after the implantation of the covered stent 100. Further, when the covered stent 100 is deployed in the blood vessel lumen and maintained for 90 days, the ratio of the average value of the first cross-sectional area of the covered stent 100 to the average value of the immediate cross-sectional area of the covered stent 100 is greater than 0.85.

[0036] In some specific embodiments, the stent body 2 is an alloy stent; the alloy material components of the stent body 2 include cobalt, titanium, and boron. The alloy stent made of this kind of material can improve the supporting performance of the stent body 2 and improve the problem of collapse of the stent body 2.

[0037] As a preferred embodiment, the material of the stent body 2 is MP35N nickel-cobalt alloy.

[0038] In some specific embodiments, the stent body 2 includes a plurality of annular stents 200 arranged longitudinally at intervals along the tubular film 1; the tubular film 1 has a microscopic morphology of a filamentous structure with oriented arrangement, and the force on at least part of the annular stents 200 can be transmitted to adjacent annular stents 200 through the filamentous structure of the tubular film 1. The filamentous structure can conduct stress along the longitudinal direction of the covered stent 100, so that the force on the annular stent 200 is dispersed to other adjacent annular stents 200, thereby improving the mechanical properties of the covered stent 100 and improving the problem of stent collapse. Further, the filamentous structure with oriented arrangement helps / synergizes the covered stent 100 to form a prestressed fold structure 1300 during the process of being compressed and clamped by the delivery system, and improves the problem of longitudinal length shortening that occurs during the delivery and release of the covered stent 100.

[0039] In some specific embodiments, the tubular film covering 1 at least includes an inner film layer 101 and an outer film layer 102, and the stent body 2 is fixedly connected between the inner film layer 101 and the outer film layer 102; the inner film layer 101 and the outer film layer 102 have different microtopographies. With such an arrangement, the mechanical anisotropy of the tubular film covering 1 is promoted, which can not only take into account the bending performance of the covered stent 100, but also improve the force dispersion performance of the local film covering of the covered stent 100 after being pressed by blood vessels, so that it can maintain the initial shape of the implanted blood vessel (such as Figure 17 the circular lumen in the immediate postoperative OCT, and until Figure 18 the circular lumen in the OCT at 90 days after surgery, with little or no change), and avoid lumen collapse (such as Figure 19 the circular lumen in the immediate postoperative OCT, and until Figure 20 the irregular cavity with the circular lumen in the OCT at 90 days after surgery collapsed into a non-circular lumen), and maintain the initial lumen rate.

[0040] In some specific embodiments, the inner film layer 101 has a microscopic morphology of a filamentous structure with an oriented arrangement; the outer film layer 102 has a microscopic morphology of a filamentous structure, and the filamentous structure of the outer film layer 102 is shorter than that of the inner film layer 101. The filamentous structure can increase the surface roughness of the outer film layer 102. By contacting the outer rough side wall of the outer film layer 102 with the blood vessel wall and providing support for the blood vessel, the anchoring of the outer film layer 102 to the vascular intima can be increased, and the displacement of the covered stent 100 after implantation can be prevented.

[0041] In some specific embodiments, the outer film layer 102 has a microscopic morphology of a filamentous structure with a non-oriented arrangement.

[0042] In some specific embodiments, the stent body 2 includes a plurality of annular stents 200 longitudinally spaced along the tubular film covering 1; the filamentous structures of the film covering between two adjacent annular stents 200 extend longitudinally along the tubular film covering 1. The filamentous structures of the tubular film covering 1 can improve the longitudinal support strength between the annular stents 200 and reduce the probability of the shortening of the longitudinal length of the covered stent 100 during the release process of the covered stent 100 due to the interaction with the balloon-expandable covered stent system.

[0043] In some specific embodiments, both ends of the filamentous structures of at least a part of the tubular film covering 1 are respectively connected to two annular stents 200. Specifically, both ends of the filamentous structures are connected to the adjacent two annular stents 200 through the film covering.

[0044] In some specific embodiments, a plurality of filamentous structures of the tubular film covering 1 between two annular stents 200 are arranged circumferentially along the covered stent 100, that is, a plurality of filamentous structures are provided between two adjacent annular stents 200 to improve the support effect.

[0045] In some specific embodiments, each annular stent 200 is cut from an alloy pipe; each annular stent 200 has a first load diameter that is sleeved on the outer surface of the inflated balloon and expands to be greater than 10% of the blood vessel diameter; when each annular stent 200 is in the first load diameter state 110, the covered stent 100 has a first load state; the covered stent 100 has a delivery state of being sleeved on the outer surface of the non-inflated balloon; the ratio of the longitudinal length value of the covered stent 100 in the first load state (expanded state / unfolded state) to the longitudinal length value of the covered stent 100 in the delivery state (compressed state 130 / unfolded state) is greater than 0.95; when the covered stent 100 is in the first load state, a part of the tubular covering film 1 is stretched by the annular stent 200 without elastic deformation (as Figure 9 shown, in the diamond-shaped area of the support monomer with the first load diameter, a relatively flat tubular covering film surface 111 is presented). When the annular stent 200 expands the narrow part, it usually covers the normal blood vessels near the narrow lesion. The blood vessel reaction forces on the blood vessels in the narrow part and the normal part are different. There are multiple annular stents 200 on the whole stent, and some annular stents 200 may expand too much, resulting in elastic deformation of the covering film. The covered stent 100 is delivered in the compressed state 130. By reasonably setting the longitudinal length of the covered stent 100 in the delivery state and enabling the annular stent 200 to support the tubular covering film 1 and at least part of the tubular covering film 1 not to produce elastic deformation when the covered stent 100 is released, the problem of the shortening of the longitudinal length of the covered stent 100 occurring during the interaction with the balloon-expandable covered stent system during the release of the covered stent 100 is improved.

[0046] In some specific embodiments, each annular stent 200 also has a second load diameter that is greater than the diameter of the alloy pipe; a part of the tubular covering film 1 can be stretched by the annular stent 200 in the second load diameter state 140 and produce elastic deformation. When the balloon 4 expands, it can cause the annular stent 200 to expand to reach the second load diameter. As Figure 4 shown, generally, the circumferential length L of the first load diameter support monomer 201 in the first load diameter state 110 is less than the circumferential length L of the second load diameter support monomer 203 in the second load diameter state 140.

[0047] In some specific embodiments, as Figure 3 and Figure 4 shown, each annular stent 200 includes a plurality of frames (first load diameter support monomer 201, compressed state support monomer 202, second load diameter support monomer 203) arranged circumferentially around the tubular covering film 1 and connected by connecting rods. The frame includes a seam with a variable shape surrounded by a continuous metal boundary; the covering film between two annular stents 200 has a circumferentially continuous tube body.

[0048] The peripheral balloon-expandable covered stent system usually consists of a covered stent 100 and a delivery system. The stent is pre-mounted on the balloon 4 of the delivery system. The stent is composed of a balloon-expandable cobalt-based alloy stent ring and a fluoropolymer. The delivery system consists of a tip, a radiopaque ring, an inner tube, a balloon 4, a catheter, a catheter reinforcement, and a catheter hub. Two radiopaque rings are located inside the balloon 4 and near both ends of the stent, marking the effective length of the balloon 4 and facilitating stent placement. The delivery system is compatible with a 0.035-inch (0.89 mm) guide wire and can be used for initial stent placement and post-stent placement dilation. The pre-mounted stent system is available in a variety of stent diameters and lengths. The catheter lengths of the pre-mounted delivery system are 75 cm and 135 cm. The peripheral balloon-expandable covered stent system is used to treat common iliac artery and external iliac artery stenosis and / or occlusive lesions.

[0049] Clinical usage examples of the covered stent 100 (such as Figure 21 shown): I) Vascular treatment 1. Establishing a vascular access a) After appropriate local anesthesia, select a suitable blood vessel to establish access. If possible, percutaneous Seldinger puncture technique is preferably selected. Epidermal incision can be performed when necessary.

[0050] b) Insert a properly sized vascular sheath into the blood vessel using standard techniques.

[0051] 2. Angiography and measurement Through angiography, evaluate and mark the lesion location or stenosis segment under X-ray, and observe the location of vascular stenosis or occlusive lesions. Measure the diameter and length of the target lesion to determine the required stent specifications. When necessary, use a measuring guide wire or catheter for measurement.

[0052] 3. Percutaneous transluminal angioplasty (PTA) a) It is recommended to pre-dilate the lesion site to facilitate the passage of the stent system.

[0053] b) Inflate the angioplasty balloon 4 to the nominal pressure. Ensure that the balloon 4 is fully expanded within the lesion site. Note: Carefully mark the boundaries of the angioplasty treatment segment to ensure complete stent coverage.

[0054] c) After deflating the balloon 4, evaluate the results using angiography. Measure the vascular diameter, the length of the lesion site, and the percentage of residual stenosis for reference.

[0055] 4. Stent sizing and selection Before opening the sterile package and removing the contents, check whether the diameter and length of the stent and the effective length of the delivery system are correct.

[0056] ● When selecting a stent of appropriate size, the blood vessels must be carefully evaluated.

[0057] Narrowed or obstructive lesion site: To reduce the likelihood of blood vessel injury, the outer diameter of the selected stent should be about 10% larger than the blood vessel diameters at the proximal and distal ends of the stenosis. To prevent stent migration, during the period from the initial deployment of the device to post-placement dilation, care should be taken to ensure that the device is in full contact with the blood vessel wall.

[0058] ● Confirm that the delivery system catheter is long enough to reach the treatment site.

[0059] II) Stent preparation 1. Carefully check whether the packaging is damaged. If the product has passed its shelf life, do not use it. Open the packaging box and take out the sterile inner packaging bag containing the stent. Starting from one corner, tear the edge of the inner packaging bag and then gently take out the stent system.

[0060] 2. Pre-use inspection: ● Before using this product, carefully check all materials and equipment used in the operation for bending, kinking or other damage.

[0061] ● Do not use any damaged or defective equipment and materials.

[0062] ● If the sterile packaging is damaged or the stent system is damaged, do not use this product.

[0063] 3. Before attaching the catheter to the guide wire, the distal end of the stent system can be bent into a circle to make the delivery system easier to track. During the bending process, care should be taken to ensure that the metal stent rings do not deform, become misaligned or get damaged.

[0064] 4. Preparation of the stent delivery system catheter: a) Connect a heparinized saline syringe to the guide wire hole of the stent system and flush the delivery catheter until a steady stream of water flows out of the catheter tip.

[0065] b) After flushing the catheter, remove the syringe.

[0066] c) Prepare a pressurizing device / syringe with diluted contrast agent (a 1:1 mixture of contrast agent and saline), or a medium considered suitable by the physician.

[0067] d) Connect the pressurizing device / syringe to a three-way stopcock (if required), and then connect it to the filling hole of the stent system.

[0068] e) Open the three-way connector leading to the stent system. Hold the distal end of the balloon 4 with the tip facing downwards, making it lower than the level of the pressurizing device / syringe. Pull the plunger of the pressurizing device / syringe to create a negative pressure and maintain it for 20 - 30 seconds. Carefully release the plunger to fill with contrast agent without applying positive pressure, as this may cause partial deployment of the stent.

[0069] f) Close the three-way connector leading to the stent system; Remove all air from the pressurizing device / syringe.

[0070] g) Repeat steps e) and f) until all air is expelled. If there are still air bubbles, do not use the stent system.

[0071] h) Connect the prepared pressurizing device / syringe to the three-way connector and open the three-way connector.

[0072] 5. Once the surface of the stent has been wetted, do not allow it to dry.

[0073] III) Introduction and positioning of the stent 1. Select a vascular sheath with a matching size and no kinks. It is recommended to use a vascular sheath with a sufficient length to pass through the lesion site. Using a vascular sheath can minimize the risk of the stent detaching from the balloon 4 during tracking. Introduce the stent into the target lesion site using standard interventional techniques.

[0074] 2. Ensure that the guide wire has a diameter of 0.035" (0.89 mm).

[0075] 3. Ensure that the position of the guide wire is maintained beyond the target lesion site while removing the balloon catheter. Avoid reintroduction until the operation is completed.

[0076] 4. Insert the distal end of the guide wire into the proximal end of the stent system, keeping the tube body as straight as possible. Carefully push the stent along the guide wire slowly (about 0.5 cm each time), through the hemostatic valve and the vascular sheath, and into the access vessel. Note: If excessive resistance is felt when guiding the stent through the hemostatic valve, withdraw and check if the product is damaged. If the stent is damaged or the covered stent 100 is displaced relative to the marker of the radiographic ring on the delivery system under fluoroscopy, do not use it.

[0077] 5. Under fluoroscopic guidance, carefully advance the delivery system along the guide wire. If excessive resistance is felt, withdraw the entire product and the vascular sheath together.

[0078] 6. Under direct X-ray observation, position the stent across the target lesion site. Using the proximal and distal radiopaque markers of the delivery system (indicating the effective length of balloon 4) and the radiopaque stent as reference points, position the stent at the lesion site. Note: After the stent is deployed, due to longitudinal shortening, the two ends of the stent will be within the effective length of balloon 4. When selecting a stent, the stent shortening factor should be taken into account to cover the expected lesion site. During positioning, confirm that the stent remains centered within the marker band and has not detached. Do not deploy the stent unless it is exactly centered on balloon 4 and correctly positioned within the target lesion site. If the stent is within the lesion site but not in the optimal position, it should be carefully repositioned or withdrawn.

[0079] If a PTA procedure is performed, the stent length should cover the entire vascular segment treated by balloon angioplasty. In appropriate cases, it is recommended that the stent extend at least 1 cm beyond the proximal and distal margins of the lesion site.

[0080] 7. When the optimal positioning is confirmed under X-ray, start to deploy the stent. Note: After the stent has been fully introduced, do not withdraw the stent back into the vascular sheath. If the stent needs to be withdrawn, withdraw it to a position close to the vascular sheath but do not enter the sheath. Then the stent system and the vascular sheath can be removed simultaneously. After removal, it cannot be used again. Do not attempt to pull the partially expanded or unexpanded stent system back into the vascular sheath as this may cause the stent to detach from balloon 4. Carefully observe whether the stent has detached or moved, and at the same time attempt to withdraw the unexpanded stent via the vascular sheath.

[0081] IV) Deployment of the stent 1. Steadily hold the delivery system at the hemostatic valve of the vascular sheath, maintaining the relative positions of the delivery system catheter and the vascular sheath with respect to the patient to reduce catheter movement during deployment and ensure accurate positioning of the stent.

[0082] 2. To reduce the likelihood of vascular injury, select a stent with an outer diameter approximately 10% larger than the vascular diameters proximal and distal to the stenosis. Use a pressurizing device to slowly inflate the stent system to the pressure required to reach the expected diameter, and maintain the inflation pressure for approximately 15 seconds. To reduce the impact of any lumen damage or stent retraction caused by the lesion site, a higher inflation pressure may be required, but the pressure should not exceed the rated burst pressure. A stent that is too large relative to the vascular diameter may cause vascular injury, and a stent that is too small may cause stent migration. The compliance table provided on the package label is generated under idealized in vitro conditions and does not take into account the characteristics of the in vivo lesion site, the blood vessels, and the variability among different patients. Therefore, the compliance chart should be used as a general guide, and the user should confirm the stent diameter and length during inflation and release of balloon 4 and by angiography.

[0083] 3. After deploying the stent, manually and slowly deflate the balloon 4 using a pressurizing device to ensure correct re - retrieval of the balloon 4. Before withdrawal, allow sufficient time for the balloon 4 to fully deflate and observe under X - ray that the balloon 4 has been fully deflated.

[0084] 4. Maintain proper vascular sheath support and very slowly withdraw the balloon 4. Observe under X - ray to ensure that the balloon 4 detaches from the stent. If resistance is encountered during the attempt to withdraw, do not force it. Determine and correct the cause of the resistance under X - ray in combination with conventional techniques and then continue.

[0085] 5. Use angiography techniques to confirm the position and deployment of the stent. For optimal results, the stent should cover the entire lesion site. Observe using X - ray to facilitate comparison of the proximal and distal ends of the stent with the reference vessel diameter and correctly judge the optimal post - dilation stent diameter.

[0086] 6. If re - sizing is required, use standard interventional techniques to re - advance the delivery system catheter or another balloon catheter of appropriate size into the area where the stent is placed.

[0087] 7. Under X - ray observation, inflate the balloon 4 to the nominal pressure, do not exceed the rated burst pressure. When using another balloon 4 for post - deployment dilation, select a balloon 4 length shorter than the length of the deployed stent. Do not expand the balloon 4 beyond the ends of the stent and into healthy blood vessels, as this may cause restenosis and subsequent failure. Deflate the balloon 4 and operate according to the previous instructions.

[0088] 8. Re - confirm the stent position and angiography results. Inflate again until the desired effect is achieved.

[0089] V) After stent deployment 1. While maintaining negative pressure within the balloon 4 and the position of the guide wire across the treatment lesion site, carefully withdraw the delivery system from the body via the vascular sheath. There may be some resistance felt when withdrawing the balloon 4 via the catheter.

[0090] Note: During the catheter withdrawal process, if the balloon 4 gets stuck on the leading edge of the vascular sheath, gently moving the catheter back and forth slightly may help dislodge it. If necessary, the delivery system and the vascular sheath can be withdrawn together as a unit. Excessive force during catheter withdrawal may damage the delivery catheter or the vascular sheath.

[0091] 2. It is recommended to perform one final angiography to evaluate vascular patency.

[0092] 3. When the clinical conditions are suitable, withdraw the vascular sheath and perform hemostasis at the puncture site.

[0093] Example 2 AsFigures 10 to 16 As shown in the figure, this embodiment provides a balloon-expandable covered stent system, which includes an elastic tube sleeve 3, a balloon 4, a mandrel (such as the balloon catheter body 420, the balloon catheter body 420 has a balloon catheter distal end 410 and a balloon catheter proximal end 430), and the covered stent 100 in Embodiment 1. The covered stent 100, the elastic tube sleeve 3, the balloon 4, and the mandrel are sleeved from outside to inside in sequence; both ends of the balloon 4 are sealed and fixedly connected to the mandrel, and can be filled and expanded through the liquid passage of the mandrel; the proximal end 302 of the elastic tube sleeve is fixedly connected to the mandrel, or the proximal end 302 of the elastic tube sleeve is fixedly connected to the proximal end 402 of the balloon; the distal end 301 of the elastic tube sleeve is movably sleeved on the balloon; the radially contracted / compressed / undeployed covered stent 100 can be removably sleeved on the elastic tube sleeve 3. The elastic tube sleeve 3 can provide an elastic carrier with a relatively thickness-depressible property for the covered stent 100, so that the covered stent 100 can be tightly loaded / hooped on the balloon-expandable covered stent system (delivery system), that is, the covered stent 100 can be recessed into the outer wall of the elastic tube sleeve 3 to a certain extent. When the loading is completed, the covered stent 100 will have a radial springback of 0.1 - 0.2 mm. At this time, the recessed part of the elastic tube sleeve 3 under the action of the covered stent 100 can also have an appropriate springback, so that the covered stent 100, the elastic tube sleeve 3, and the balloon 4 can better contact, ensuring sufficient friction between the covered stent 100, the elastic tube sleeve 3, and the balloon 4. When the covered stent 100 is withdrawn from the delivery sheath, the displacement and shortening in the length direction of the covered stent 100 can be reduced; when the balloon 4 expands, the covered stent 100 is radially expanded. Due to the friction between the elastic tube sleeve 3 and the covered stent 100, the displacement and shortening in the length direction of the covered stent 100 during the expansion process are reduced.

[0094] In some specific embodiments, the balloon-expandable covered stent system can be expanded from an undeployed state with an undeployed diameter (such as Figure 10 shown) to a deployed state with a deployed diameter (such as Figure 16 shown); such as Figure 11As shown, in the balloon-expandable covered stent system in the unexpanded state, the covered stent 100 is configured to have prestress, or the elastic tube sleeve 3 is configured to have prestress, or the balloon 4 is configured to have prestress; for example, the prestressed fold structure 1300 (including the fold structure 1301 and the herringbone fold structure 1302) formed between each annular stent 200 (the first annular stent 210, the second annular stent 220, the third annular stent 230, the fourth annular stent 240), the prestressed fold structure 1300 is circumferentially and longitudinally spaced along the covered stent 100; again for example, the cavity at the end of the balloon 4 (near the balloon distal end 401 or the balloon proximal end 402) pre-stores gas or liquid, so that the end section of the balloon 4 bulges slightly / protrudes (usually, the height of the bulge / protrusion is level with the height of the end of the covered stent 100, or higher than the height of the end of the covered stent 100), to form the pillow structure 5 (pillow); the length between the two ends of the covered stent 100 is less than the length between the two ends of the balloon 4, to ensure that one end of the balloon 4 (the end away from the balloon catheter proximal end 430) can protrude relative to the edge of the end of the covered stent 100, to form the pillow structure 5 (pillow).

[0095] In some specific embodiments, the prestress design is also applied to the balloon delivery system / structure without an elastic tube sleeve. The balloon delivery system / structure without an elastic tube sleeve is a common (or commercially available) balloon catheter; that is, the covered stent 100 on the balloon catheter has a prestressed fold structure 1300, or the balloon has a pillow structure 5.

[0096] In some specific embodiments, as Figure 12 shown, the covered stent 100 in the unexpanded state is distributed with a number of fold structures 1301 formed by prestress and developing longitudinally. Usually, the fold structure 1301 extends from one end of a ring stent support monomer to the gap between another ring stent support monomer; for example, the fold structure 1301 extends from one end of the first support monomer 2101 of the first annular stent 210 to the gap between the first support monomer 2201 and the second support monomer 2202 of the second annular stent 220 of the annular stent 220. It can be understood that, like the crease of origami, the crease area of the fold structure 1301 can enhance the longitudinal compression resistance compared to the flat covering film (for example, the relatively flat tubular covering film surface 111), that is, enhance the anti-shortening performance of the covered stent 100. Usually, the size of one end of a single fold structure 1301 near the distal end 103 of the covered stent 100 is smaller than the size of the end away from the distal end 103 of the covered stent 100.

[0097] In some specific embodiments, during the deployment process of the balloon-expandable covered stent system, the fold structure 1301 can inhibit the longitudinal shortening of the covered stent 100.

[0098] In some specific embodiments, such as Figure 10 , Figure 14 and Figure 15 shown, the balloon 4 in the undeployed state has a pillow structure 5. As Figure 10 shown, the cavity at the end of the balloon 4 (near the distal end 401 or the proximal end 402 of the balloon) pre-stores gas or liquid, causing the end segment of the balloon 4 to slightly bulge / protrude to form the pillow structure 5. As Figure 14 shown, generally, when passing through the sheath channel constructed by the percutaneous Seldinger puncture technique or the blood vessel lumen, the pillow structure 5 of the balloon-expandable covered stent system will be squeezed and deformed by the sheath wall or the blood vessel wall, forcing the pre-stored gas or liquid in the balloon 4 to be squeezed and filled into the balloon segment covered by the covered stent 100, lifting the balloon wall in this area, making the inner wall 403 of the balloon away from the balloon catheter body 420, and the outer wall 404 of the balloon applying a force to the inner wall of the elastic tube sleeve 3, dynamically compensating for the force between the inner wall of the covered stent 100 and the outer wall of the elastic tube sleeve 3 (or filling the newly generated gap between the inner wall of the covered stent 100 and the outer wall of the elastic tube sleeve 3), and inhibiting the covered stent 100 from being dislodged.

[0099] In some specific embodiments, such as Figure 10 shown, in the balloon-expandable covered stent system in the undeployed state, gas or liquid is pre-stored in the cavity of the balloon 4 to form a pillow structure 5 with the two ends (such as the distal end 401 or the proximal end 402 of the balloon) protruding relative to the middle.

[0100] In some specific embodiments, during the process of delivering the covered stent 100 to the target blood vessel lumen by the balloon-expandable covered stent system, the pillow structure 5 of the balloon 4 can inhibit the covered stent 100 from being dislodged from the balloon-expandable covered stent system.

[0101] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A covered stent, comprising a stent body connected by a tubular covering film, characterized in that, The covered stent has a non-loaded state with a zero compression diameter and a loaded state for supporting blood vessel to restore blood flow with a compression ratio relative to the non-loaded state; when the compression ratio of the covered stent is 10%, the numerical range of the radial supporting force of the covered stent is 2.0 N / mm - 6.0 N / mm.

2. The covered stent according to claim 1, wherein, When the compression ratio of the covered stent is 10%, the numerical range of the radial supporting force of the covered stent is 3.0 N / mm - 4.5 N / mm.

3. The covered stent according to claim 2, wherein At the starting moment when the covered stent is deployed in the blood vessel lumen in the loaded state, the cross-sectional area of the hollow cavity of the covered stent is the immediate cross-sectional area; when the covered stent is deployed in the blood vessel lumen and maintained for 90 days, the cross-sectional area of the hollow cavity of the covered stent is the first cross-sectional area, and the ratio of the average value of the first cross-sectional area of the covered stent to the average value of the immediate cross-sectional area of the covered stent is greater than 0.

7.

4. The covered stent according to claim 1, characterized in that, The stent body is an alloy stent; the alloy material components of the stent body include cobalt, titanium, and boron.

5. The covered stent according to claim 4, characterized in that, The material of the stent body is MP35N nickel-cobalt alloy.

6. The covered stent according to any one of claims 1 to 5, characterized in that, The stent body includes a plurality of annular stents longitudinally spaced along the longitudinal direction of the tubular covering; the tubular covering has a microscopic morphology of a filamentous structure arranged in an oriented manner, and the force on at least part of the annular stents can be transmitted to the adjacent annular stents through the filamentous structure of the tubular covering.

7. The covered stent according to claim 6, wherein The tubular covering at least includes an inner covering layer and an outer covering layer, and the stent body is fixedly connected between the inner covering layer and the outer covering layer; the inner covering layer and the outer covering layer have different microscopic morphologies.

8. The covered stent according to claim 7, characterized in that, The inner covering layer has a microscopic morphology of a filamentous structure arranged in an oriented manner; the outer covering layer has a filamentous structure microscopic morphology, and the filamentous structure of the outer covering layer is shorter than the filamentous structure of the inner covering layer.

9. The covered stent according to claim 6, wherein The filamentous structure of the covering between two adjacent annular stents of the tubular covering extends along the longitudinal direction of the tubular covering.

10. The covered stent according to claim 9, wherein The two ends of the filamentous structure of at least part of the tubular covering are respectively connected to two of the annular stents.

11. The covered stent according to claim 9, characterized in that, The multiple filamentous structures of the tubular covering between two of the annular stents are arranged along the circumferential direction of the covered stent.

12. The covered stent according to claim 6, characterized in that, Each of the annular stents is cut from an alloy pipe; each of the annular stents has a first loaded diameter equal to the diameter of the alloy pipe; when the annular stent is in the first loaded diameter state, the covered stent has a first loaded state; the covered stent has a delivery state of being sleeved on the outer surface of a non-inflated balloon; the ratio of the longitudinal length value of the covered stent in the first loaded state to the longitudinal length value of the covered stent in the delivery state is greater than 0.95; when the covered stent is in the first loaded state, part of the tubular covering is stretched by the annular stent without elastic deformation.

13. The covered stent according to claim 12, characterized in that, Each of the annular stents also has a second loaded diameter greater than the diameter of the alloy pipe; part of the tubular covering can be stretched by the annular stent in the second loaded diameter state and generate elastic deformation.

14. A balloon-expandable covered stent system, characterized in that, It includes an elastic tube sheath, a balloon, a mandrel, and the covered stent according to any one of claims 1 to 13. The covered stent, the elastic tube sheath, the balloon, and the mandrel are sleeved in sequence from outside to inside; both ends of the balloon are hermetically and fixedly connected to the mandrel; the proximal end of the elastic tube sheath is fixedly connected to the mandrel, or the proximal end of the elastic tube sheath is fixedly connected to the proximal end of the balloon; the distal end of the elastic tube sheath is movably sleeved on the balloon; the radially contracted covered stent is removably sleeved on the elastic tube sheath.

15. The balloon-expandable covered stent system according to claim 14, wherein, The balloon-expandable covered stent system can be expanded from an unexpanded state with an unexpanded diameter to an expanded state with an expanded diameter; In the unexpanded state of the balloon-expandable covered stent system, the covered stent is configured to have prestress, or the elastic tube sheath is configured to have prestress, or the balloon is configured to have prestress.

16. The balloon-expandable covered stent system according to claim 15, wherein In the unexpanded state, the covered stent is distributed with a number of pleated structures formed by prestress and developing longitudinally.

17. The balloon-expandable covered stent system according to claim 16, wherein During the expansion process of the balloon-expandable covered stent system, the pleated structure can inhibit the longitudinal shortening of the covered stent.

18. The balloon-expandable covered stent system according to claim 15, wherein, In the unexpanded state, the balloon has a pillow structure.

19. The balloon-expandable covered stent system according to claim 18, wherein In the unexpanded state of the balloon-expandable covered stent system, gas or liquid is pre-stored in the balloon cavity to form the pillow structure with the two ends protruding relative to the middle.

20. The balloon-expandable covered stent system according to claim 19, wherein During the process of the balloon-expandable covered stent system delivering the covered stent into the target blood vessel cavity, the pillow structure of the balloon can inhibit the covered stent from being detached from the balloon-expandable covered stent system.

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