Stent grafts and balloon-expandable stent graft systems

Abstract

The present invention discloses a stent graft and a balloon-expandable stent graft system, which relate to the field of medical device technology. The stent graft includes a stent body connected by a tubular coating. The stent graft has a non-load state with a zero compression diameter and a loaded state with a compression rate relative to the non-load state for supporting the blood vessel to restore blood flow. When the compression rate of the stent graft is 10%, the radial support force of the stent graft has a numerical range of 2.0N / mm-6.0N / mm. The balloon-expandable stent graft system includes an elastic sleeve, a balloon, a core shaft and a stent graft. The stent graft, the elastic sleeve, the balloon and the core shaft are sequentially arranged from the outside to the inside, and the two ends of the balloon are sealed with the core shaft. The proximal end of the elastic sleeve is fixedly connected to the core shaft or to the proximal end of the balloon. The distal end of the elastic sleeve is movably mounted on the balloon. The present invention can provide moderate support for the blood vessel and can effectively improve the problems of lumen restenosis and stent collapse after implantation of the existing stent graft.

Description

Technical Field

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

[0002] A stent graft consists of a metal stent coated with a special membrane material. It is a medical device used to treat stenosis or obstruction in various parts of the body. Specifically, a peripheral vascular stent graft is used to treat peripheral arterial disease (such as stenosis, aneurysm, or rupture). Currently, stent grafts often provide excessive or insufficient radial support for the blood vessels. Significant vascular stenosis or stent collapse often occurs 90 days after implantation, with a stenosis rate of up to 17.4%. Summary of the Invention

[0003] 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, provide moderate support for blood vessels, and effectively improve the problems of lumen restenosis and stent collapse after implantation of the existing covered stent.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a coated stent, comprising a stent body connected by a tubular coating, the coated stent having a non-loaded state with a zero compression diameter, and a loaded state with a compression rate relative to the non-loaded state for supporting a blood vessel to restore blood flow; when the compression rate of the coated stent is 10%, the numerical range of the radial support force of the coated stent is 2.0N / mm-6.0N / mm.

[0006] Preferably, when the compression rate of the stent graft is 10%, the radial support force of the stent graft has a numerical range of 3.0 N / mm-4.5 N / mm.

[0007] Preferably, at the initial moment when the stent graft is deployed in the lumen of a blood vessel in a loaded state, the cross-sectional area of ​​the hollow lumen of the stent graft is the immediate cross-sectional area; when the stent graft is deployed in the lumen of the blood vessel and maintained for 90 days, the cross-sectional area of ​​the hollow lumen of the stent graft is the first cross-sectional area, and the ratio of the average value of the first cross-sectional area of ​​the stent graft to the average value of the immediate cross-sectional area of ​​the stent graft is greater than 0.7. Furthermore, when the stent graft is deployed in the lumen of the blood vessel and maintained for 90 days, the ratio of the average value of the first cross-sectional area of ​​the stent graft to the average value of the immediate cross-sectional area of ​​the stent graft is greater than 0.85.

[0008] Preferably, the stent body is an alloy stent; the alloy material components of the stent body include cobalt, titanium and boron.

[0009] Preferably, the material of the bracket body is MP35N nickel-cobalt alloy.

[0010] Preferably, the stent body includes a plurality of annular stents arranged at intervals along the longitudinal direction of the tubular coating; the tubular coating has a microscopic morphology of a filamentous structure arranged in an orientation, and at least part of the force applied to the annular stents can be transmitted to the adjacent annular stents through the filamentous structure of the tubular coating.

[0011] Preferably, the tubular coating comprises at least an inner coating layer and an outer coating layer, and the stent body is fixedly connected between the inner coating layer and the outer coating layer; the inner coating layer and the outer coating layer have different microscopic morphologies.

[0012] Preferably, the inner coating layer has a microscopic morphology of an orientationally arranged filamentous structure; the outer coating layer has a microscopic morphology of a filamentous structure, and the filamentous structure of the outer coating layer is shorter than that of the inner coating layer.

[0013] Preferably, the filamentous structure of the tubular covering between two adjacent annular stents extends in the longitudinal direction of the tubular covering.

[0014] Preferably, at least two ends of the filamentous structure of a portion of the tubular coating are respectively connected to two of the annular supports.

[0015] Preferably, the multiple filamentous structures of the tubular coating between the two annular stents are arranged along the circumference of the coating stent.

[0016] Preferably, each of the annular stents is cut from an alloy tube; each of the annular stents has a first load diameter that is the same as the diameter of the alloy tube; when the annular stent is in the first load diameter state, the coated stent has a first load state; the coated stent has a conveying state in which it is sleeved on the outer surface of a non-filled balloon; the ratio of the longitudinal length value of the coated stent in the first load state to the longitudinal length value of the coated stent in the conveying state is greater than 0.95; when the coated stent is in the first load state, part of the tubular coating is supported by the annular stent without elastic deformation.

[0017] Preferably, each of the annular supports further has a second load diameter that is larger than the diameter of the alloy tube; a portion of the tubular coating can be expanded by the annular supports in the second load diameter state and produce elastic deformation.

[0018] The present invention also provides a balloon-expandable coated stent system, comprising an elastic sleeve, a balloon, a core shaft and the coated stent, wherein the coated stent, the elastic sleeve, the balloon and the core shaft are sequentially arranged from the outside to the inside; the two ends of the balloon are sealed and fixedly connected to the core shaft; the proximal end of the elastic sleeve is fixedly connected to the core shaft, or the proximal end of the elastic sleeve is fixedly connected to the proximal end of the balloon; the distal end of the elastic sleeve is movably sleeved on the balloon; the radially contracted coated stent can be removably sleeved on the elastic sleeve.

[0019] Preferably, the balloon-expandable covered stent system can be expanded from an undeployed state having an undeployed diameter to an expanded state having an expanded diameter; in the balloon-expandable covered stent system in the undeployed state, the covered stent is constructed to have prestress, or the elastic sleeve is constructed to have prestress, or the balloon is constructed to have prestress.

[0020] Preferably, the stent graft in the undeployed state is distributed with a plurality of fold structures formed by prestress and developed in the longitudinal direction.

[0021] Preferably, during the deployment of the balloon-expandable stent graft system, the pleated structure can suppress the longitudinal shortening of the stent graft.

[0022] Preferably, the balloon in an undeployed state has a pillow structure.

[0023] Preferably, in the balloon-expandable covered stent system in the undeployed state, gas or liquid is pre-stored in the balloon cavity to form the pillow structure with two ends protruding relative to the middle.

[0024] Preferably, during the process of the balloon-expandable stent graft system delivering the stent graft into the target blood vessel cavity, the pillow structure of the balloon can inhibit the stent graft from being detached from the balloon-expandable stent graft system.

[0025] Compared with the prior art, the present invention has achieved the following technical effects:

[0026] The present invention provides a stent graft and a balloon-expandable stent graft system, comprising a stent body connected by a tubular coating. The stent graft has an unloaded state with a zero compressed diameter, and a loaded state with a compression ratio relative to the unloaded state for supporting a blood vessel to restore blood flow. When the compression ratio of the stent graft is 10%, the radial support force of the stent graft ranges from 2.0N / mm to 6.0N / mm. The stent graft supports the blood vessel in the loaded state. By setting the radial support force of the stent graft to 2.0N / mm to 6.0N / mm, the stent graft can provide moderate support for the blood vessel, effectively improving the problems of lumen restenosis and stent collapse after implantation of existing stent grafts. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic structural diagram of the stent graft provided in Example 1;

[0029] Figure 2 A schematic structural diagram of the tubular coating provided in Example 1;

[0030] Figure 3 A schematic structural diagram of the stent body in the first load diameter state and the clamped state provided in Example 1;

[0031] Figure 4 Schematic diagram of the supporting monomer structure of the stent body in the first load diameter state and the second load diameter state provided in Example 1;

[0032] Figure 5 Providing an OCT image view of the stent graft under load after implantation in a blood vessel for Example 1;

[0033] Figure 6 Schematic diagram of the microscopic morphology of the oriented filamentous structure of the tubular coating Figure 1 ;

[0034] Figure 7 Schematic diagram of the microscopic morphology of the oriented filamentous structure of the tubular coating Figure 2 ;

[0035] Figure 8 Schematic diagram of the microscopic morphology of the non-oriented arranged filamentous structure of the tubular film;

[0036] Figure 9 The stent graft has a relatively flat tubular graft in a first load diameter state;

[0037] Figure 10 A schematic structural diagram of the balloon-expandable covered stent system provided in Example 2;

[0038] Figure 11 A partial schematic diagram of a balloon-expandable covered stent system configured to have prestress;

[0039] Figure 12 for Figure 11 Schematic diagram of the folded structure of the stent graft system in the undeployed state;

[0040] Figure 13 for Figure 11 Schematic diagram of the herringbone fold structure of the stent graft system in the undeployed state;

[0041] Figure 14 A partial diagram of the balloon-expandable covered stent system in the undeployed state, where the balloon forms a pillow structure with two opposing ends facing each other in the middle. Figure 1 ;

[0042] Figure 15 A partial diagram of the balloon-expandable covered stent system in the undeployed state, where the balloon forms a pillow structure with two opposing ends facing each other in the middle. Figure 2 ;

[0043] Figure 16 A schematic structural diagram of a balloon-expandable covered stent delivery system provided by the present invention;

[0044] Figure 17 Animal experimental images of the stent graft provided in Example 1 Figure 1 ;

[0045] Figure 18 Animal experimental images of the stent graft provided in Example 1 Figure 2 ;

[0046] Figure 19 for Figure 17 In animal experiments, images of commercially available products as the control group Figure 1 ;

[0047] Figure 20 for Figure 17 In animal experiments, images of commercially available products as the control group Figure 2 ;

[0048] Figure 21 This is a clinical image of the stent graft provided in Example 1;

[0049] In the figure: 100, stent graft; 1, tubular graft; 101, inner graft layer; 102, outer graft layer; 103, distal end of stent graft; 110, first loaded diameter state; 120, loaded state; 130, gripped state; 140, second loaded diameter state; 111, relatively flat tubular graft surface; 1300, prestressed pleated structure; 1301, pleated structure; 1302, herringbone pleated structure;

[0050] 2. Bracket body; 200, annular bracket; 210, first annular bracket; 220, second annular bracket; 230, third annular bracket; 240, fourth annular bracket; 201, first load diameter support unit; 202, grip state support unit; 203, second load diameter support unit; 2101, first support unit of the first annular bracket; 2201, first support unit of the second annular bracket; 2202, second support unit of the second annular bracket;

[0051] 3. Elastic sleeve; 301. Distal end of elastic sleeve; 302. Proximal end of elastic sleeve;

[0052] 4. Balloon; 401. Distal end of balloon; 402. Proximal end of balloon; 403. Inner wall of balloon; 404. Outer wall of balloon; 410. Distal end of balloon catheter; 420. Balloon catheter body; 430. Proximal end of balloon catheter;

[0053] 5. Pillow structure. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] It should be noted that, in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," "outer," "front," "back," "center," "longitudinal," "lateral," "length," "width," "thickness," "vertical," "horizontal," "top," "bottom," "clockwise," and "counterclockwise" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are merely for ease of description and are not intended to indicate or imply that the device or component described must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood broadly. For example, they can mean fixed, detachable, or integral; mechanical or electrical; direct or indirect through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0056] 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, provide moderate support for blood vessels, and effectively improve the problems of lumen restenosis and stent collapse after implantation of the existing covered stent.

[0057] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0058] Example 1

[0059] like Figures 1 to 21 As shown, this embodiment provides a coated stent 100, comprising a stent body 2 connected by a tubular coating 1, the coated stent 100 having a non-load state with zero compression diameter (in the non-load state, the supporting monomer of the annular stent 200 is usually diamond-shaped), and a loaded state 120 with a compression rate relative to the non-load state for supporting the blood vessel to restore blood flow; when the compression rate of the coated stent 100 is 10%, the numerical range of the radial support force of the coated stent 100 is 2.0N / mm-6.0N / mm. By setting the radial support force of the coated stent 100 with a compression rate of 10% to 2.0N / mm-6.0N / mm, when the coated stent 100 is placed in the blood vessel lumen in the loaded state 120 to support the blood vessel, it can provide moderate support for the blood vessel, and can effectively improve the problems of lumen restenosis and stent collapse after implantation of the existing coated stent 100; as shown Figures 17 to 20 As shown, the animal implantation experiment verified that the stent graft 100 has excellent support performance compared with the common balloon-expandable stent grafts on the market; after 90 days of implantation, the stent graft 100 did not collapse (see Figure 18 90 days after surgery, DSA and OCT images showed that the stent graft 100 as a whole and at the arrow point maintained a relatively complete stent lumen, with a low lumen loss rate and a vascular stenosis rate of approximately 8.6%. The control group of the commercially available product showed obvious vascular stenosis and stent collapse (see Figure 20 , DSA and OCT images 90 days after surgery, the control group of commercially available products showed collapse as a whole and at the point indicated by the arrow, with a high lumen loss rate and a vascular stenosis rate of approximately 17.4%).

[0060] It should be noted that the zero-compression diameter refers to the natural diameter of the stent graft 100 when fully expanded (not subjected to external compression or extension). The radial support force of the stent graft 100 must be tested in accordance with "YY / T 1660-2019 Radial Load Test Method for Balloon-Expandable and Self-Expanding Stents," meaning the radial support force of the stent graft 100 must be tested at a compression ratio of 10%. The stent graft 100 features a bridgeless design, offering excellent compliance. The support unit utilizes a diamond-shaped ring design, which, through simulation, has been shown to exhibit high radial strength, fatigue resistance, and post-expansion performance. This structural unit exhibits excellent anti-collapse properties in practical applications, improving vascular patency. Animal studies comparing the stent graft 100 to existing marketed products demonstrate that the stent graft 100 exhibits improved vascular patency and stent collapse resistance.

[0061] In some specific embodiments, the diameter of the coated stent 100 is approximately 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 in the blood vessel, the coated stent 100 is released and contacts the normal blood vessel and is compressed. After being released, the coated stent 100 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. The compression rate of the coated stent 100 when placed in the blood vessel for support is approximately 10%.

[0062] As a preferred embodiment, when the compression rate of the stent graft 100 is 10%, the radial support force of the stent graft 100 has a numerical range of 3.0 N / mm-4.5 N / mm.

[0063] In some specific embodiments, at the initial moment when the stent graft 100 is deployed in the lumen of a blood vessel in a loaded state 120, the cross-sectional area of ​​the hollow lumen of the stent graft 100 is the immediate cross-sectional area; when the stent graft 100 is deployed in the lumen of a blood vessel and maintained for 90 days, the cross-sectional area of ​​the hollow lumen of the stent graft 100 is the first cross-sectional area, and the ratio of the average first cross-sectional area of ​​the stent graft 100 to the average immediate cross-sectional area of ​​the stent graft 100 is greater than 0.7, that is, this embodiment significantly improves the problems of lumen restenosis and stent loss after implantation of the stent graft 100. Furthermore, when the stent graft 100 is deployed in the lumen of a blood vessel and maintained for 90 days, the ratio of the average first cross-sectional area of ​​the stent graft 100 to the average immediate cross-sectional area of ​​the stent graft 100 is greater than 0.85.

[0064] In some 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 using this material can improve the support performance of the stent body 2 and improve the problem of stent body 2 collapsing.

[0065] As a preferred embodiment, the material of the bracket body 2 is MP35N nickel-cobalt alloy.

[0066] In some specific embodiments, the stent body 2 includes a plurality of annular stents 200 spaced longitudinally along the tubular coating 1; the tubular coating 1 has a microscopic morphology of a filamentous structure arranged in an orientation, and the force on at least part of the annular stents 200 can be transmitted to the adjacent annular stents 200 through the filamentous structure of the tubular coating 1. The filamentous structure can transmit stress along the longitudinal direction of the coated stent 100, so that the force on the annular stent 200 can be dispersed to other adjacent annular stents 200, thereby improving the mechanical properties of the coated stent 100 and improving the problem of stent collapse. Furthermore, the orientationally arranged filamentous structure helps / cooperates with the coated stent 100 to form a prestressed pleated structure 1300 in the process of squeezing and tightening the delivery system, thereby improving the problem of longitudinal length shortening that occurs during the delivery and release of the coated stent 100.

[0067] In some specific embodiments, the tubular coating 1 includes at least an inner coating layer 101 and an outer coating layer 102, and the stent body 2 is fixedly connected between the inner coating layer 101 and the outer coating layer 102; the inner coating layer 101 and the outer coating layer 102 have different microscopic morphologies. This configuration promotes the mechanical anisotropy of the tubular coating 1, which can not only take into account the bending performance of the coated stent 100, but also improve the force dispersion performance of the local coating of the coated stent 100 after being pressurized by the blood vessel, so that it maintains its original shape after being implanted in the blood vessel (such as Figure 17 The circular lumen of OCT immediately after surgery, Figure 18 90 days after surgery, OCT showed a circular lumen with little or no change), avoiding lumen collapse (e.g. Figure 19 The circular lumen of OCT immediately after surgery, Figure 20 90 days after surgery, the OCT image collapsed into an irregular cavity with a non-circular lumen), maintaining the initial lumen rate.

[0068] In some specific embodiments, the inner coating layer 101 has an oriented filamentous microstructure; the outer coating layer 102 has a filamentous microstructure, with the filaments of the outer coating layer 102 being shorter than those of the inner coating layer 101. The filamentous structure can increase the surface roughness of the outer coating layer 102. The rough outer wall of the outer coating layer 102 contacts the blood vessel wall and provides support for the blood vessel, thereby enhancing the anchoring of the outer coating layer 102 to the blood vessel intima and preventing displacement of the covered stent 100 after implantation.

[0069] In some specific embodiments, the outer coating layer 102 has a non-oriented filamentous structure microstructure.

[0070] In some embodiments, the stent body 2 includes a plurality of annular stents 200 spaced longitudinally along the tubular covering 1. The filamentous structure of the tubular covering 1 between adjacent annular stents 200 extends longitudinally along the tubular covering 1. The filamentous structure of the tubular covering 1 enhances the longitudinal support strength between the annular stents 200 and reduces the likelihood of longitudinal shortening of the stent graft 100 due to interaction with the balloon-expandable stent graft system during the release of the stent graft 100.

[0071] In some specific embodiments, at least two ends of the filamentary structure of a portion of the tubular coating 1 are respectively connected to two annular stents 200 . Specifically, the two ends of the filamentary structure are connected to two adjacent annular stents 200 through the coating.

[0072] In some specific embodiments, the multiple filamentous structures of the tubular coating 1 between two annular stents 200 are arranged along the circumference of the coating stent 100, that is, multiple filamentous structures are provided between two adjacent annular stents 200 to improve the supporting effect.

[0073] In some specific embodiments, each annular stent 200 is cut from an alloy tube; each annular stent 200 has a first load diameter that is sleeved on the outer surface of a filled balloon to expand to a diameter greater than 10% of the blood vessel diameter; when each annular stent 200 is in the first load diameter state 110, the coated stent 100 has a first load state; the coated stent 100 has a transport state that is sleeved on the outer surface of a non-filled balloon; the ratio of the longitudinal length value of the coated stent 100 in the first load state (expanded state / expanded state) to the longitudinal length value of the coated stent 100 in the transport state (gripped state 130 / undeployed state) is greater than 0.95; when the coated stent 100 is in the first load state, part of the tubular coating 1 is expanded by the annular stent 200 without elastic deformation (such as Figure 9 As shown, a relatively flat tubular coating surface 111 is presented in the rhombus region of the support monomer of the first load diameter. When the annular stent 200 is expanded at the stenosis site, it usually covers the normal blood vessels near the stenosis lesion. The blood vessels at the stenosis site and the normal site are subjected to different vascular reaction forces. There are multiple annular stents 200 on the entire stent. Some of the annular stents 200 may be expanded too much, causing elastic deformation of the coating. The coated stent 100 is transported in a gripping state 130. By reasonably setting the longitudinal length of the coated stent 100 in the transport state, and enabling the annular stent 200 to support the tubular coating 1 when the coated stent 100 is released, and preventing at least part of the tubular coating 1 from elastic deformation, the problem of shortening of the longitudinal length of the coated stent 100 caused by the interaction with the balloon expansion coated stent system during the release of the coated stent 100 is improved.

[0074] In some specific embodiments, each annular stent 200 further has a second load diameter that is larger than the diameter of the alloy tube; the portion of the tubular coating 1 can be stretched and elastically deformed by the annular stent 200 in the second load diameter state 140. When the balloon 4 is expanded, the annular stent 200 can be expanded to reach the second load diameter. Figure 4 As shown, generally, the circumferential length L of the first load diameter supporting unit 201 of the first load diameter state 110 is smaller than the circumferential length L of the second load diameter supporting unit 203 of the second load diameter state 140 .

[0075] In some specific embodiments, such as Figure 3 and Figure 4 Each annular bracket 200 includes a plurality of frames (a first load diameter support unit 201, a gripping state support unit 202, and a second load diameter support unit 203) arranged circumferentially around the tubular coating 1 and connected by connecting rods. The frame includes a seam with a changeable shape surrounded by a continuous metal boundary; the coating between the two annular brackets 200 has a circumferentially continuous tubular body.

[0076] The peripherally expanded balloon-grafted stent system typically consists of a stent graft 100 and a delivery system, with the stent pre-installed 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 distal tip, a contrast ring, an inner tube, the balloon 4, a catheter, a catheter reinforcement, and a catheter hub. Two contrast rings are located within the balloon 4 and near each end of the stent, indicating the effective length of the balloon 4 and facilitating stent placement. The delivery system is compatible with a 0.035-inch (0.89 mm) guidewire and can be used for both initial stent placement and post-stent expansion. Pre-installed stent systems are available in a variety of stent diameters and lengths. Pre-installed delivery system catheters are available in 75 cm and 135 cm lengths. The peripherally expanded balloon-grafted stent system is used to treat stenotic and / or occlusive lesions of the common and external iliac arteries.

[0077] Examples of clinical use of the stent graft 100 (eg Figure 21 shown):

[0078] 1) Vascular treatment

[0079] 1. Establish vascular access

[0080] a) After appropriate local anesthesia, select a suitable vascular access technique. If possible, a percutaneous Seldinger puncture technique is preferred. A superficial cutaneous incision may be performed if necessary.

[0081] b) Using standard techniques, insert an appropriately sized vascular sheath into the vessel.

[0082] 2. Imaging and Measurement

[0083] Angiography assesses and marks the location of lesions or stenosis segments under X-rays to observe the location of vascular stenosis or occlusion. The diameter and length of the target lesion are measured to determine the required stent specifications. If necessary, a measuring guidewire or catheter is used for measurement.

[0084] 3. Percutaneous transluminal angioplasty (PTA)

[0085] a) Pre-dilation of the lesion is recommended to facilitate the passage of the stent system.

[0086] b) Inflate the angioplasty balloon 4 to the nominal pressure. Ensure that the balloon 4 is fully expanded within the lesion. Note: Carefully mark the boundaries of the angioplasty treatment segment to ensure complete stent coverage.

[0087] c) After balloon 4 is deflated, angiography is used to evaluate the results. The vessel diameter, lesion length, and residual stenosis percentage are measured for reference.

[0088] 4. Stent Sizing and Selection

[0089] Before opening the sterile packaging and removing the contents, check that the diameter and length of the stent and the effective length of the delivery system are correct.

[0090] ● Careful assessment of the vessel is necessary to select the appropriate size stent.

[0091] Stenotic or obstructive lesions: To minimize the possibility of vascular damage, the outer diameter of the stent should be approximately 10% larger than the vessel diameter proximal and distal to the stenosis. To prevent stent migration, ensure that the device is in close contact with the vessel wall during initial deployment and post-implantation expansion.

[0092] ● Verify that the delivery system catheter is of sufficient length to reach the treatment site.

[0093] 2) Stent Preparation

[0094] 1. Carefully inspect the packaging for damage. Do not use if the expiration date has expired. Open the box and remove the sterile inner bag containing the stent. Starting from one corner, tear open the edge of the inner bag and gently remove the stent system.

[0095] 2. Check before use:

[0096] ● Before using this product, carefully inspect all materials and equipment used in the procedure for bends, kinks, or other damage.

[0097] ● Do not use any damaged or defective equipment or materials.

[0098] ● Do not use the product if the sterile packaging is damaged or the stent system is damaged.

[0099] 3. Before placing the catheter over the guidewire, the distal end of the stent system can be bent into a round shape to make the delivery system easier to track. During the bending process, care should be taken to ensure that the metal stent ring is not deformed, dislocated, or damaged.

[0100] 4. Preparation of the stent delivery system catheter:

[0101] a) Connect a syringe of heparinized saline to the guidewire port of the stent system and flush the delivery catheter until a steady stream of water is emitted from the catheter tip.

[0102] b) After flushing the catheter, remove the syringe.

[0103] c) Prepare the charging device / syringe with diluted contrast medium (a 1:1 mixture of contrast medium and saline), or any other medium deemed appropriate by the physician.

[0104] d) Connect the inflation device / syringe to the T-connector (if necessary) and then to the inflation port of the stent system.

[0105] e) Open the three-way connector leading to the stent system. With the distal balloon tip facing downward, lower than the level of the inflation device / syringe, pull the plunger of the inflation device / syringe to create negative pressure and maintain it for 20-30 seconds. Carefully release the plunger until there is no pressure to inflate the contrast agent. Do not apply positive pressure at this time, as this may cause partial deployment of the stent.

[0106] f) Close the T-connector to the support system; purge all air from the inflation device / syringe.

[0107] g) Repeat steps e) and f) until all air is removed. If air bubbles remain, do not use the bracket system.

[0108] h) Connect the prepared charging device / syringe to the T-connector and open the T-connector.

[0109] 5. Once the bracket surface has been moistened, do not allow it to dry out.

[0110] 3) Introduction and positioning of the stent

[0111] 1. Select a vascular sheath of appropriate size and free of kinks. It is recommended to use a sheath long enough to pass through the lesion. Using a vascular sheath can minimize the risk of the stent being dislodged from the balloon during tracking. Use standard interventional techniques to introduce the stent into the target lesion.

[0112] 2. Ensure the guidewire diameter is 0.035" (0.89mm).

[0113] 3. Ensure that the guidewire remains positioned beyond the target lesion while the balloon catheter is removed until the procedure is complete to avoid reintroduction.

[0114] 4. Insert the tail end of the guidewire into the head end of the stent system, keeping the tube as straight as possible. Carefully advance the stent slowly (approximately 0.5 cm at a time) along the guidewire, passing through the hemostatic valve and vascular sheath, and into the access vessel. Note: If excessive resistance is felt when guiding the stent through the hemostatic valve, remove it and inspect it for damage. Do not use the stent if it is damaged or if the stent graft 100 is displaced relative to the imaging ring marker on the delivery system as observed under X-ray.

[0115] 5. Under X-ray guidance, carefully advance the delivery system along the guidewire. If you feel excessive resistance, remove the product and vascular sheath together.

[0116] 6. Under direct X-ray visualization, position the stent across the target lesion. Using the proximal and distal markers on the delivery system (indicating the effective length of balloon 4) and the radiopaque stent as reference points, position the stent at the lesion. Note: After stent deployment, both ends of the stent will be within the effective length of balloon 4 due to longitudinal shortening. This shortening should be factored into stent selection to ensure coverage of the intended lesion. During positioning, confirm that the stent remains centered within the marker band and has not fallen out. Do not deploy the stent unless it is centered on balloon 4 and correctly positioned within the target lesion. If the stent is within the lesion but not in the optimal position, it should be carefully repositioned or withdrawn.

[0117] If a PTA is performed, the stent should cover the entire vessel segment treated with balloon angioplasty. Where appropriate, it is recommended that the stent extend at least 1 cm beyond the proximal and distal edges of the lesion.

[0118] 7. After confirming optimal positioning under X-ray, begin deploying the stent. Note: Do not withdraw the stent into the sheath after it has been fully introduced. To withdraw the stent, withdraw it close to the sheath but not into it. The stent system and sheath can then be removed simultaneously. Once removed, it must not be reused. Do not attempt to withdraw a partially expanded or unexpanded stent system into the sheath, as this may cause the stent to dislodge from the balloon 4. Carefully observe the stent for dislodgement or movement while attempting to withdraw the unexpanded stent through the sheath.

[0119] 4) Deployment of the stent

[0120] 1. Maintain the delivery system stably at the hemostatic valve of the vascular sheath, maintain the position of the delivery system catheter and vascular sheath relative to the patient, and reduce catheter movement during deployment to ensure accurate positioning of the stent.

[0121] 2. To reduce the possibility of vascular injury, the stent outer diameter should be approximately 10% larger than the vessel diameter proximal and distal to the stenosis. Use the inflation device to slowly inflate the stent system to the pressure required to achieve the desired diameter, maintaining the inflation pressure for approximately 15 seconds. To minimize the effects of any luminal damage or stent recoil due to the lesion site, higher inflation pressures may be required, but the pressure must not exceed the rated burst pressure. Oversizing a stent relative to the vessel diameter may cause vascular injury, while undersizing may result in stent migration. The compliance chart provided on the package label is generated under idealized in vitro conditions and does not account for in vivo lesion site characteristics, vascular characteristics, and interpatient variability. Therefore, the compliance chart should be used as a general guide, and the user should confirm the stent diameter and length during balloon inflation and deployment and by angiography.

[0122] 3. After deploying the stent, use the inflation device to manually and slowly deflate the balloon 4 to ensure proper recapture of the balloon 4. Before withdrawing the stent, allow sufficient time for the balloon 4 to be completely deflated and observe the complete deflation of the balloon 4 under X-ray.

[0123] 4. Maintaining proper sheath support, very slowly withdraw balloon 4. Observe under X-ray to ensure that balloon 4 is detached from the stent. If resistance is encountered during withdrawal, do not force withdrawal. Use X-ray and conventional techniques to determine and correct the cause of the resistance before continuing.

[0124] 5. Use angiography to confirm the position and deployment of the stent. For optimal results, the stent should cover the entire lesion. X-rays are used to compare the proximal and distal ends of the stent with the reference vessel diameter to accurately determine the optimal post-expansion stent diameter.

[0125] 6. If resizing is necessary, re-advance the delivery system catheter or another balloon catheter of appropriate size to the stented area using standard interventional techniques.

[0126] 7. Under X-ray observation, inflate balloon 4 to the nominal pressure, but do not exceed the rated burst pressure. When using another balloon 4 for post-implantation dilation, select a balloon 4 that is shorter than the deployed stent length. Do not inflate balloon 4 beyond the ends of the stent and into healthy vessels, as this may cause restenosis and subsequent failure. Deflate balloon 4 and proceed as described above.

[0127] 8. Reconfirm the stent position and angiographic results. Inflate again until the desired effect is achieved.

[0128] 5) After the stent is deployed

[0129] 1. While maintaining the negative pressure within the balloon 4 and the guidewire position across the treatment lesion, carefully withdraw the delivery system from the body through the vascular sheath. You may feel some resistance when withdrawing the balloon 4 through the catheter.

[0130] Note: During catheter withdrawal, if balloon 4 becomes lodged in the leading edge of the sheath, gently moving the catheter back and forth may help dislodge it. If necessary, the delivery system and sheath can be withdrawn together. Excessive force or force during catheter withdrawal may damage the delivery catheter or sheath.

[0131] 2. A final angiogram is recommended to assess vascular patency.

[0132] 3. When clinical conditions are suitable, remove the vascular sheath and stop bleeding at the puncture site.

[0133] Example 2

[0134] like Figures 10 to 16As shown, this embodiment provides a balloon-expandable coated stent system, comprising an elastic sleeve 3, a balloon 4, a core shaft (for example, a balloon catheter body 420, the balloon catheter body 420 having a balloon catheter distal end 410 and a balloon catheter proximal end 430) and the coated stent 100 in Example 1, the coated stent 100, the elastic sleeve 3, the balloon 4 and the core shaft are sequentially arranged from the outside to the inside; both ends of the balloon 4 are sealed and fixedly connected to the core shaft, and can be inflated and expanded through the liquid channel of the core shaft; the proximal end 302 of the elastic sleeve is fixedly connected to the core shaft, or the proximal end 302 of the elastic sleeve is fixedly connected to the proximal end 402 of the balloon; the distal end 301 of the elastic sleeve is movably mounted on the balloon; the radially contracted / compressed / unexpanded coated stent 100 can be removably mounted on the elastic sleeve 3. The elastic sleeve 3 can provide a relatively thick and concave elastic carrier for the stent graft 100, so that the stent graft 100 can be tightly loaded / clamped on the balloon-expandable stent graft system (delivery system), that is, the stent graft 100 can be concave to a certain extent in the outer wall of the elastic sleeve 3. When the loading is completed, the stent graft 100 will have a radial rebound of 0.1 to 0.2 mm. At this time, the concave part of the elastic sleeve 3 under the action of the stent graft 100 can also have an appropriate rebound, so that the stent graft 100 can be tightly loaded / clamped on the balloon-expandable stent graft system (delivery system). 00, the elastic sleeve 3 and the balloon 4 can better contact each other, ensuring that there is sufficient friction between the coated stent 100, the elastic sleeve 3 and the balloon 4. When the coated stent 100 is withdrawn from the delivery sheath, the displacement and shortening of the coated stent 100 in the length direction can be reduced; when the balloon 4 expands, the coated stent 100 expands radially. Due to the friction between the elastic sleeve 3 and the coated stent 100, the displacement and shortening of the coated stent 100 in the length direction during the expansion process is reduced.

[0135] In some embodiments, the balloon-expandable stent graft system can be expanded from an undeployed state (e.g., Figure 10 ) to an expanded state having an expanded diameter (as shown Figure 16 As shown); Figure 11As shown, in the balloon-expandable stent graft system in the undeployed state, the stent graft 100 is configured to have prestress, or the elastic sleeve 3 is configured to have prestress, or the balloon 4 is configured to have prestress; for example, prestressed pleated structures 1300 (including pleated structures 1301 and herringbone pleated structures 1302) are formed between the annular stents 200 (the first annular stent 210, the second annular stent 220, the third annular stent 230, and the fourth annular stent 240), and the prestressed pleated structures 1300 are spaced apart circumferentially along the stent graft 100 and spaced apart longitudinally along the stent graft 100; For another example, gas or liquid is pre-stored in the cavity of the end of the balloon 4 (near the distal end 401 or the proximal end 402 of the balloon) so that the end segment of the balloon 4 is slightly raised / convex (usually, the height of the raised / convex is level with the height level of the end of the coated stent 100, or higher than the height level of the end of the coated stent 100) to form a pillow structure 5 (pillow); the length between the two ends of the coated stent 100 is smaller 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 proximal end 430 of the balloon catheter) can extend relative to the edge of the end of the coated stent 100 to form a pillow structure 5 (pillow).

[0136] In some embodiments, the prestressed design is also applied to a balloon delivery system / structure without an elastic sheath. The balloon delivery system / structure without an elastic sheath is a conventional (or commercially available) balloon catheter; that is, the stent graft 100 on the balloon catheter has a prestressed corrugated structure 1300 , or the balloon has a pillow structure 5 .

[0137] In some specific embodiments, such as Figure 12 As shown, the undeployed stent graft 100 is distributed with a plurality of prestressed longitudinally extending folds 1301. Typically, the folds 1301 extend from one end of a ring-shaped stent strut to the gap between the struts of another ring-shaped stent; for example, the folds 1301 extend from one end of a first strut 2101 of a first ring-shaped stent 210 to the gap between the first strut 2201 and the second strut 2202 of a second ring-shaped stent 220. It will be appreciated that, like the folds in origami, the folds of the folds 1301 can enhance the longitudinal compression resistance compared to a flat graft (e.g., the relatively flat tubular graft surface 111), thereby enhancing the stent graft 100's resistance to shortening. Typically, the dimension of a single fold 1301 near the distal end 103 of the stent graft 100 is smaller than the dimension away from the distal end 103 of the stent graft 100.

[0138] In some specific embodiments, during the deployment of the balloon-expandable stent graft system, the pleated structure 1301 can inhibit the longitudinal shortening of the stent graft 100 .

[0139] In some specific embodiments, such as Figure 10 、 Figure 14 and Figure 15 As shown, the balloon 4 in the unexpanded state has a pillow structure 5. Figure 10 As shown, the end of the balloon 4 (near the distal end 401 or the proximal end 402) is pre-stored with gas or liquid in the cavity, so that the end section of the balloon 4 is slightly raised / convex to form a pillow structure 5. Figure 14 As shown, usually, when passing through the sheath channel or the vascular cavity constructed by the percutaneous Seldinger puncture technique, the pillow structure 5 of the balloon-expandable coated 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 coated stent 100, lifting the balloon wall in this area, so that the inner wall 403 of the balloon is away from the balloon catheter body 420, and the outer wall 404 of the balloon applies a force to the inner wall of the elastic tube sleeve 3, dynamically compensating for the force between the inner wall of the coated stent 100 and the outer wall of the elastic tube sleeve 3 (or filling the newly generated gap between the inner wall of the coated stent 100 and the outer wall of the elastic tube sleeve 3), thereby suppressing the coated stent 100 from being detached.

[0140] In some specific embodiments, such as Figure 10 As 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 both ends (such as the distal end 401 or the proximal end 402 of the balloon) protruding relative to the middle.

[0141] In some specific embodiments, during the process of the balloon-expandable stent graft system delivering the stent graft 100 into the target blood vessel lumen, the pillow structure 5 of the balloon 4 can inhibit the stent graft 100 from being detached from the balloon-expandable stent graft system.

[0142] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A stent graft comprising a stent body connected by a tubular graft, characterized in that: The stent graft has an unloaded state with zero compressed diameter and a loaded state with a compression ratio relative to the unloaded state for supporting a blood vessel to restore blood flow. When the compression ratio of the stent graft is 10%, the radial support force of the stent graft ranges from 2.0 N / mm to 6.0 N / mm. The stent body is an alloy stent. The alloy material components of the stent body include cobalt, titanium, and boron. The material of the stent body is MP35N nickel-cobalt alloy. The stent body includes a plurality of annular stents arranged at intervals along the longitudinal direction of the tubular coating; each of the annular stents is cut from an alloy tube; each of the annular stents has a first load diameter that is the same as the diameter of the alloy tube; when the annular stent is in the first load diameter state, the coated stent has a first load state; the coated stent has a conveying state in which it is sleeved on the outer surface of a non-filled balloon; the ratio of the longitudinal length value of the coated stent in the first load state to the longitudinal length value of the coated stent in the conveying state is greater than 0.95; when the coated stent is in the first load state, part of the tubular coating is supported by the annular stent without elastic deformation; each of the annular stents has the first load diameter that is sleeved on the outer surface of the filled balloon to expand; Each of the annular supports includes a plurality of frames which are circumferentially arranged around the tubular covering and connected by connecting rods, and there is no connecting bridge between adjacent annular supports.

2. The stent graft according to claim 1, wherein: When the compression rate of the stent graft is 10%, the radial support force of the stent graft has a numerical range of 3.0 N / mm-4.5 N / mm.

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

7.

4. The stent graft according to any one of claims 1 to 3, characterized in that: The tubular coating has a microscopic morphology of a filamentous structure arranged in an orientation, and at least a portion of the force applied to the annular stent can be transferred to the adjacent annular stent through the filamentous structure of the tubular coating.

5. The stent graft according to claim 4, characterized in that: The tubular coating at least includes an inner coating layer and an outer coating layer, and the stent body is fixedly connected between the inner coating layer and the outer coating layer; the inner coating layer and the outer coating layer have different microscopic morphologies.

6. The stent graft according to claim 5, characterized in that: The inner coating layer has a microscopic morphology of a filamentous structure arranged in an orientation; the outer coating layer has a microscopic morphology of a filamentous structure, and the filamentous structure of the outer coating layer is shorter than that of the inner coating layer.

7. The stent graft according to claim 5, characterized in that: The filamentous structure of the tubular covering between two adjacent annular stents extends along the longitudinal direction of the tubular covering.

8. The stent graft according to claim 7, wherein: Two ends of the filamentous structure of at least a portion of the tubular covering are respectively connected to the two annular supports.

9. The stent graft according to claim 7, characterized in that: The multiple filamentous structures of the tubular coating between the two annular stents are arranged along the circumference of the coated stent.

10. The stent graft according to claim 1, wherein: Each of the annular supports also has a second load diameter that is larger than the diameter of the alloy tube; a portion of the tubular coating can be expanded by the annular supports in the second load diameter state and generate elastic deformation.

11. A balloon-expandable stent graft system, characterized in that: The invention comprises an elastic sleeve, a balloon, a core shaft, and the coated stent according to any one of claims 1 to 10, wherein the coated stent, the elastic sleeve, the balloon, and the core shaft are sequentially sleeved from the outside to the inside; both ends of the balloon are sealed and fixedly connected to the core shaft; the proximal end of the elastic sleeve is fixedly connected to the core shaft, or the proximal end of the elastic sleeve is fixedly connected to the proximal end of the balloon; the distal end of the elastic sleeve is movably sleeved on the balloon; The radially contracted stent graft is removably sleeved on the elastic sleeve; The balloon-expandable covered stent system is capable of being expanded from an undeployed state having an undeployed diameter to a deployed state having an expanded diameter; In the balloon-expandable stent graft system in an undeployed state, the stent graft is configured to have prestress, or the elastic sleeve is configured to have prestress, or the balloon is configured to have prestress.

12. The balloon-expandable stent graft system according to claim 11, characterized in that: The stent graft in the undeployed state is distributed with a plurality of fold structures formed by prestress and developed in the longitudinal direction.

13. The balloon-expandable stent graft system according to claim 12, characterized in that: During the deployment of the balloon-expandable stent graft system, the pleated structure can inhibit longitudinal shortening of the stent graft.

14. The balloon-expandable stent graft system according to claim 11, characterized in that: The balloon in an undeployed state has a pillow configuration.

15. The balloon-expandable stent graft system according to claim 14, characterized in that: In the balloon-expandable covered stent system in the undeployed state, gas or liquid is pre-stored in the balloon cavity to form the pillow structure with two ends bulging relative to the middle.

16. The balloon-expandable stent graft system according to claim 15, characterized in that: During the process of the balloon-expandable stent graft system delivering the stent graft into the target blood vessel lumen, the pillow structure of the balloon can inhibit the stent graft from being detached from the balloon-expandable stent graft system.

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