Branched ball expansion type covered stent system and preparation method thereof

Abstract

The invention discloses a branch-type ball-expanding covered stent system and a preparation method thereof, and relates to the field of medical instruments, the branch-type ball-expanding covered stent system comprises a main covered stent and a branch covered stent, and the main covered stent and the branch covered stent are both ball-expanding covered stents; the branch covered stent is fixedly connected to the side wall of the main covered stent, and an inner cavity of the branch covered stent is communicated with an inner cavity of the main covered stent; the main covered stent is used for being arranged in a main blood vessel, and the branch covered stent is used for being arranged in a branch blood vessel of the main blood vessel. The preparation method comprises the steps that a branch type covered stent is obtained, the branch type covered stent comprises a main covered stent body and a branch covered stent body, and the main covered stent body and the branch covered stent body are both balloon expanding type covered stent bodies; the branch covered stent bodies are fixedly connected to the side wall of the main covered stent body, and inner cavities of the branch covered stent bodies are communicated with an inner cavity of the main covered stent body. According to the invention, the supporting force, the wall adhesion and the load shedding resistance of the covered stent can be improved, the surgical risk is reduced, and the long-term patency rate is improved.

Description

Technical Field

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

[0002] Covered stents are widely used to treat lesions such as stenosis, occlusion, or abnormal dilatation of vascular and non-vascular cavities. Covered stents can be categorized by their release method into self-expanding and balloon-expandable stents. In balloon-expandable stents, the stent graft is placed outside the balloon and is released from the diseased vessel by expanding the balloon.

[0003] The traditional balloon-expandable covered stent is difficult to meet the needs of treating vascular diseases of branched blood vessels. For example, stenosis of the common iliac artery and the external iliac artery is a common peripheral vascular disease. When treating vascular lesions of such branched blood vessels, if a traditional balloon-expandable covered stent is used, the covered stent will cover the stenotic segments of the common iliac artery and the external iliac artery at the same time, which will cause the internal iliac artery to be blocked by the outer wall of the stent coating, leading to complications such as gluteal ischemia and sexual dysfunction. In the prior art, treatment is often performed by opening a hole in the side wall of the covered stent. The internal iliac artery can be connected to the inner cavity of the covered stent through the hole, thereby solving the problem of the internal iliac artery being blocked by the outer wall of the stent coating. However, this type of covered stent has defects such as insufficient support, poor wall adhesion, and easy unloading. Therefore, there is an urgent need for a new balloon-expandable covered stent that can effectively treat main blood vessel stenosis and protect branched blood vessels. Summary of the Invention

[0004] The purpose of the present invention is to provide a branched balloon-expandable covered stent system and its preparation method to solve the problems existing in the above-mentioned prior art, which can improve the supporting force, wall adhesion and anti-unloading ability of the covered stent, reduce surgical risks and improve long-term patency rate.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a branched balloon-expandable covered stent system, comprising a main covered stent and a branch covered stent, wherein the main covered stent and the branch covered stent are both balloon-expandable covered stents; the branch covered stent is fixedly connected to the side wall of the main covered stent, and the inner cavity of the branch covered stent is connected to the inner cavity of the main covered stent; the main covered stent is used to be placed in a main blood vessel, and the branch covered stent is used to be placed in a branch blood vessel of the main blood vessel; the main covered stent has a mixed radial support performance along its length direction; the branch covered stent has a relatively uniform radial support performance along its length direction.

[0007] Preferably, an opening is provided in the middle of the side wall of the main stent graft, and the branch stent graft is fixedly connected to the opening of the main stent graft.

[0008] Preferably, an opening is provided at one end of the side wall of the main stent graft, and the branch stent graft is fixedly connected to the opening of the main stent graft.

[0009] Preferably, the outer side wall of the main stent graft at the periphery of the opening is coated with antithrombotic drugs and biocompatible substances, and the outer side wall of the branch stent graft at the periphery of the opening is coated with antithrombotic drugs and biocompatible substances.

[0010] Preferably, the main stent graft comprises a main stem graft and a plurality of main stent units sequentially arranged along the length direction of the main stem graft; the main stem graft is provided with the opening; and at least one open stent unit is provided on both sides of the opening.

[0011] Preferably, the branch stent graft comprises a branch tubular graft and a plurality of branch stent units sequentially arranged along the length direction of the branch tubular graft; each of the branch stent units is a closed stent unit.

[0012] Preferably, each of the branch support units is made of flexible metal or cobalt-chromium alloy.

[0013] Preferably, each of the branch support units is an annealed support.

[0014] Preferably, the plurality of main support units between the tube section of the main tube-shaped covering with the opening and the tube end section of the main tube-shaped covering are all closed support units.

[0015] Preferably, it also includes a main balloon and a branch balloon; the main balloon is used to be sleeved inside the main coated stent, and the main coated stent can be expanded and attached to the main blood vessel by expanding the main balloon; the branch balloon is used to be sleeved inside the branch coated stent, and the branch coated stent can be expanded and attached to the branch blood vessel by expanding the branch balloon.

[0016] The present invention also provides a method for preparing the branched balloon-expandable coated stent system, comprising the following steps: obtaining a branched coated stent, the branched coated stent comprising the main coated stent and the branch coated stent, the main coated stent and the branch coated stent both being balloon-expandable coated stents; the branch coated stent being fixedly connected to the side wall of the main coated stent, the inner cavity of the branch coated stent being connected to the inner cavity of the main coated stent; the main coated stent having a mixed radial support performance along its length, and the branch coated stent having a relatively uniform radial support performance along its length.

[0017] Preferably, the main coated stent and the branch coated stent are obtained separately; the method for obtaining the main coated stent includes: cutting the alloy tube to obtain a plurality of stent units, processing openings on the coating, heat shrinking or bonding the coating to the stent units; and fixing the branch coated stent to the opening of the main coated stent.

[0018] Preferably, the processing method of the opening includes: cutting the opening on the tubular coating of the main coating stent by laser cutting; and performing plasma treatment on the edge of the opening.

[0019] Compared with the prior art, the present invention has achieved the following technical effects:

[0020] The present invention provides a branched balloon-expandable covered stent system and a preparation method thereof, comprising a main covered stent and a branch covered stent, both of which are balloon-expandable covered stents; the branch covered stent is fixedly connected to the side wall of the main covered stent, and the inner cavity of the branch covered stent is connected to the inner cavity of the main covered stent; the main covered stent is used to be placed in the main blood vessel, and the branch covered stent is used to be placed in the branch blood vessel of the main blood vessel, the main covered stent has a mixed radial support performance along its length direction; the branch covered stent has a relatively uniform radial support performance along its length direction. In addition to the main stent graft, this embodiment also provides a branch stent graft for placement in a branch vessel. While treating diseases such as main vessel stenosis, it ensures blood flow in the branch vessel, thereby reducing complications. Both the main stent graft and the branch stent graft are balloon-expandable stent grafts, which can be pressed and fitted onto the main vessel and the branch vessel, respectively, by balloon expansion, thereby improving the stent graft's support, wall adhesion, and resistance to unloading, reducing surgical risks, and improving long-term patency. By optimizing the radial support performance along the length of the main stent graft, the radial support performance of the main stent graft along the length direction is differentially distributed, which can improve the stent graft's support, wall adhesion, and resistance to unloading. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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.

[0022] Figure 1 A schematic structural diagram of the first branched balloon-expandable stent graft system provided by the present invention;

[0023] Figure 2 A front view of a first branched balloon-expandable stent graft system provided by the present invention;

[0024] Figure 3 Schematic diagram of the structure of the second branched balloon-expandable covered stent system provided by the present invention Figure 1 ;

[0025] Figure 4 Schematic diagram of the structure of the second branched balloon-expandable covered stent system provided by the present invention Figure 2 ;

[0026] Figure 5 A front view of a third branched balloon-expandable covered stent system provided by the present invention;

[0027] Figure 6 A schematic structural diagram of a third branched balloon-expandable covered stent system provided by the present invention;

[0028] Figure 7 A partial schematic diagram of the iliac artery / iliac vein;

[0029] Figure 8 A schematic diagram of the structure of a main stent graft provided by the present invention Figure 1 ;

[0030] Figure 9 A schematic structural diagram of a branch stent graft provided by the present invention;

[0031] Figure 10 A schematic diagram of the unfolded plane and three-dimensional structure of an open main support unit provided by the present invention;

[0032] Figure 11 A schematic diagram of the structure of a main stent graft provided by the present invention Figure 2 ;

[0033] Figure 12 The present invention provides a schematic diagram of the unfolded planar and three-dimensional structure of an open main stent unit located on both sides of a branch covered stent;

[0034] Figure 13Schematic diagram of the unfolded planar and three-dimensional structure of a closed main support unit with a connecting rod provided by the present invention;

[0035] Figure 14 A schematic diagram of the unfolded planar structure of a connecting rod-free closed main support unit provided by the present invention;

[0036] Figure 15 Schematic diagram of a balloon delivery system carrying a main stent graft or a branch stent graft in different states;

[0037] Figure 16 A schematic structural diagram of the balloon-expandable stent delivery system provided in Example 2;

[0038] Figure 17 A partial schematic diagram of a balloon-expandable stent delivery system configured to have prestress;

[0039] Figure 18 for Figure 17 Schematic diagram of the folded structure of the stent graft system in the undeployed state;

[0040] Figure 19 for Figure 17 Schematic diagram of the herringbone fold structure of the stent graft system in the undeployed state;

[0041] Figure 20 A partial diagram of the balloon-expandable stent delivery system in the undeployed state, where the balloon forms a pillow structure with two opposing ends and a central bulge. Figure 1 ;

[0042] Figure 21 A partial diagram of the balloon-expandable stent delivery system in the undeployed state, where the balloon forms a pillow structure with two opposing ends and a central bulge. Figure 2 ;

[0043] Figure 22 A schematic structural diagram of a balloon-expandable covered stent delivery system provided in Example 2;

[0044] Figure numbers: 100, branched balloon-expandable covered stent system; 1, main covered stent; 101, opening; 102, main tubular covering; 103, main stent unit; 2, branch covered stent; 201, branch tubular covering; 202, branch stent unit; 1031, corrugated open metal ring; 1032, high-strength alloy closed main stent unit 1; 10321, support rod 1; 10322, connecting rod; 1033, open main stent unit; 10331, support rod 2; 10332, opening avoidance support rod; 1034, closed main stent unit; 1035, high-strength alloy open main stent unit 1; 1036, high-strength alloy open main stent unit 2; 1037, high-strength alloy closed main stent unit 2; 1038, high-strength alloy open main stent unit 3; 1039, high-ductility alloy open main stent unit 1; 10391, high-ductility Alloy open main stent unit 2; 10392, high strength alloy open main stent unit 4; 10393, high strength alloy closed main stent unit 3; 10394, high ductility alloy closed main stent unit; 10395, high strength alloy closed main stent unit 4; 10396, high strength alloy open main stent unit 5; 500, iliac artery / iliac vein; 501, common iliac artery cavity; 502, internal iliac artery cavity; 503, iliac External arterial cavity; 601, undeployed state; 602, deployed state; 603, state of the covered stent after release; 3, elastic sleeve; 301, distal end of the elastic sleeve; 302, proximal end of the elastic 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, balloon catheter body; 430, proximal end of the balloon catheter; 5, pillow structure; 1000, stent. DETAILED DESCRIPTION

[0045] 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.

[0046] It should be noted that in the description of the present invention, terms such as "upper", "lower", "left", "right", "inside", "outside", "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. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as limiting the present invention. In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0047] 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 in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections 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.

[0048] The purpose of the present invention is to provide a branched balloon-expandable covered stent system and its preparation method to solve the problems existing in the prior art, which can improve the supporting force, wall adhesion and anti-unloading ability of the covered stent, reduce surgical risks and improve long-term patency rate.

[0049] 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.

[0050] Example 1

[0051] like Figures 1 to 7As shown, this embodiment provides a branched balloon-expandable stent graft system 100, including a main stent graft 1 and a branch stent graft 2, both of which are balloon-expandable stent grafts 4; the branch stent graft 2 is fixedly connected to the side wall of the main stent graft 1, and the inner cavity of the branch stent graft 2 is connected to the inner cavity of the main stent graft 1; the main stent graft 1 is used to be placed in the main blood vessel, and the branch stent graft 2 is used to be placed in the branch blood vessel of the main blood vessel. The main stent graft 1 has a mixed radial support performance along its length (in other words, the main stent graft 1 has a mixed radial support force value along its length); the branch stent graft 2 has a relatively uniform radial support performance along its length (in other words, the branch stent graft 2 has a relatively uniform radial support force value along its length). In addition to the main stent graft 1, this embodiment also provides a branch stent graft 2 for placement in a branch vessel, which ensures blood flow in the branch vessel while treating diseases such as main vessel stenosis, thereby reducing complications; and both the main stent graft 1 and the branch stent graft 2 are balloon 4-expandable stent grafts, which can be pressed and fitted onto the main vessel and the branch vessel respectively by expanding the balloon 4, thereby enhancing the supporting force, wall adhesion and anti-unloading ability of the stent graft, reducing surgical risks and improving long-term patency rate. The main stent graft 1 and the branch stent graft 2 are placed in different vascular cavity environments, and the corresponding vascular cavity support requirements are also different; the vascular cavity environment in which the main stent graft 1 is located (the lumen is larger than the vascular lumen size in which the branch stent graft 2 is located, such as the common iliac artery and the internal iliac artery) often has a large blood flow rate and high pulse intensity; under the combined effect of fluid mechanics, the main stent graft 1 is more likely to have problems such as displacement and poor wall adhesion after placement; the fluid mechanics of the vascular cavity environment in which the branch stent graft 2 is located is relatively simple; therefore, the radial support performance (radial support force value) of the main stent graft 1 is optimized along its length direction to form a mixed radial support performance (for example, a main stent unit 103 with strong radial support performance is formed - The main stent unit 103 with weak radial support performance is deployed at intervals—the main stent unit 103 with strong radial support performance; for example, the main coated stent 1 is sequentially distributed in the length direction with high ductility area—high strength area—high ductility area—high strength area, or high strength area—high ductility area—high ductility area—high strength area, as well as other different combinations of hybrid radial support performance; for example, the main coated stent 1 is distributed in the length direction with differentiated radial support force values / different stent units) to achieve high-strength support for diseased blood vessels and low-strength support for normal blood vessels (especially to meet the support requirements of diseased areas / calcified plaques / stenosis areas that are staggered (intermittently) distributed along the length of the blood vessels).The radial support performance of the branch stent graft 2 is highly ductile (or highly strong) along its length. This design enables the branched balloon-expandable stent graft system 100 to improve the long-term patency rate and avoid mutual interference between the main stent graft 1 and the branch stent graft 2 (especially the displacement and collapse of the main stent graft 1, which causes the branch stent graft 2 to be displaced after interference, rendering the sealing effect of the joint between the two stents ineffective). There are at least three technical routes to achieve the above effects: the first technical route is that when the wall thickness and wall width dimensions (i.e., geometric dimensions) of the same stent unit morphology (for example, all are open, or all are closed) are the same / unchanged, the stent units at both ends of the main coated stent 1 are annealed (to maintain elasticity / high ductility to avoid damage to normal blood vessels), and the stent units in the middle part are non-annealed (to maintain high strength / relatively high radial support force to avoid collapse and loss of lumen of diseased blood vessels); the second technical route is that when the morphology of the same stent unit is in an annealed state, the radial support force / radial support performance between each stent unit is differentiated by changing the wall thickness and wall width dimensions of the stent unit; the third technical route is hybrid optimization, with differentiation of morphology and structure between stent units, differentiation of metal crystal form between stent units (i.e., a combination of annealing and non-annealing treatments), and differentiation of morphology and geometric dimensions between stent units (for example, increasing wall thickness or reducing wall thickness); thereby achieving a hybrid radial support performance of the main coated stent 1 along its length direction (in other words, achieving a hybrid radial support force value of the main coated stent 1 along its length direction). Furthermore, one end of the main stent graft 1 is configured to be disposed within or adjacent to the common iliac artery lumen 501 of the iliac artery / iliac vein 500, the other end of the main stent graft 1 is configured to be disposed within or adjacent to the external iliac artery lumen 503, and one end of the branch stent graft 2 is configured to communicate and engage with the sidewall of the main stent graft 1 via the internal iliac artery lumen 502; blood within the common iliac artery lumen 501 is guided to flow into the internal iliac artery lumen 502 via the branch stent graft 2. It is understood that by optimizing the radial support performance along the length of the main stent graft 1, the radial support performance of the main stent graft 1 along the length exhibits a differentiated distribution (e.g., Figure 1 , a mixture of high strength and high ductility, a mixture of closed and open types), can enhance the support force, wall adhesion and anti-unloading ability of the stent graft.

[0052] It should be noted that the typical annealing treatment involves heating the cobalt-chromium alloy to 800-1000°C under an inert atmosphere for 1-2 hours, followed by slow cooling. This eliminates processing stresses, promotes dislocation movement and repairs crystal defects, and forms a uniform annealed structure, maintaining high ductility and enhancing resistance to vascular stenosis. Non-annealing, on the other hand, involves directly cold-working the cobalt-chromium alloy to preserve the work-hardening effect and maintain a high dislocation density and crystal defects.

[0053] Stent unit design in the middle section of the main covered stent 1: Compared with the open structure, the use of closed main stent units 1034 (such as continuous annular support units) can provide stable radial support and enhance the ability of the middle section to resist vascular stenosis.

[0054] Stent unit design at both end sections of the main covered stent 1: Compared with the closed type, the use of open type (such as C-shaped or U-shaped support units) can reduce the radial support force at both ends, making it easier to fit the normal blood vessel wall.

[0055] For the bracket units with the same structural form (all closed or all open), their geometric dimensions (mainly the wall thickness and wall width of support rod 1 10321 and support rod 2 10331) directly affect the radial support force value of the bracket unit; further increasing the value relative to the original size value can improve the radial support force value of the bracket unit.

[0056] In some specific embodiments, an opening 101 is provided in the middle of the main stent graft 1 , and the branch stent graft 2 is fixedly connected to the opening 101 of the main stent graft 1 . The branch stent graft 2 communicates with the main stent graft 1 through the opening 101 .

[0057] In some specific embodiments, an opening 101 is provided at one end of the main stent graft 1 , and the branch stent graft 2 is fixedly connected to the opening 101 of the main stent graft 1 .

[0058] It should be noted that the opening 101 in this embodiment can be set in the middle position or end section of the main coated stent 1. Its specific setting position is determined according to the positional relationship between the main blood vessel and the branch blood vessel, etc., to ensure that the position of the opening 101 is aligned with the branch blood vessel opening 101 when the coated stent is placed in place.

[0059] In some embodiments, the outer wall of the main stent graft 1 outside the opening 101 is coated with an antithrombotic drug and a biocompatible substance, and the outer wall of the branch stent graft 2 outside the opening 101 is coated with an antithrombotic drug and a biocompatible substance to reduce the risk of thrombosis. The antithrombotic drug is preferably heparin, and the biocompatible substance is preferably an endothelial progenitor cell capture coating.

[0060] In some specific embodiments, the main coated stent 1 includes a main tube-shaped coating 102 and a plurality of main stent units 103 arranged in sequence along the length direction of the main tube-shaped coating 102; an opening 101 is provided on the main tube-shaped coating 102; and at least one open stent unit is provided on both sides of the opening 101. As a preferred embodiment, an open stent unit is provided on both sides of the opening 101, that is, the main stent units 103 on both sides of the opening 101 are open stent units (such as open main stent units 1033). After the branch coated stent 2 is implanted at the opening 101, it is necessary to continue to expand the branch coated stent 2. Due to the open stent units outside the opening 101, the opening 101 can have space for continued expansion; at the same time, it can increase the flexibility of the stent at the bifurcation of the blood vessel.

[0061] In some embodiments, the branch stent graft 2 includes a branch tubular graft 201 and a plurality of branch stent units 202 arranged sequentially along the length of the branch tubular graft 201. Each branch stent unit 202 is a closed stent unit to reduce radial support force of the branch stent unit 202 and minimize irritation to the branch vessels. The stent units are flexibly connected by the graft, increasing the compliance of the graft.

[0062] In some specific embodiments, each branch stent unit 202 is made of a flexible metal or a cobalt-chromium alloy. Flexible metal has high elastic deformation capability, good flexibility, and fatigue resistance, while cobalt-chromium alloy has advantages such as high strength, high hardness, and corrosion resistance, thereby meeting the use requirements of the branch stent graft 2. The flexible metal may be a metal such as nickel-titanium alloy.

[0063] In some embodiments, each branch stent unit 202 is an annealed stent. Annealing of the branch stent unit 202 retains a high dislocation density and crystal defects, enhances material ductility, reduces the radial support force of the branch stent graft 2, and facilitates adhesion to normal blood vessel walls.

[0064] In some specific embodiments, a plurality of closed stent units are provided on the tube end between the tube section of the main tube-shaped covering 102 with the opening 101 and the tube end section of the main tube-shaped covering 102. When the opening 101 is provided at one end of the covered stent, the tube section between the two ends of the covered stent is provided with a plurality of closed stent units; when the opening 101 is provided in the middle of the covered stent, the tube section where the opening 101 and the open stent units on both sides of the opening 101 are located is the tube section of the main tube-shaped covering 102 with the opening 101 (the tube section where the opening 101 is located), and a plurality of closed stent units are provided between the tube section where the opening 101 is located and the two tube end sections. Through the above-mentioned arrangement, the radial support force of the middle section of the covered stent can be improved to better resist lumen stenosis.

[0065] In some specific embodiments, such as Figures 3 to 6 As shown, the hybrid radial support performance regional distribution can be achieved by hybrid deployment of several different main support units 103. For example, Figure 3 and 4 , the branch stent graft 2 is arranged on one side of the end of the main stent graft 1. If the main stent units 103 on both sides of the branch stent graft 2 are both high-ductility open main stent units, then the main area of the main stent graft 1 has insufficient support performance for the branch stent graft 2 and is prone to fatigue failure under the action of blood pulses; the optimization is: using a pair of high-strength alloy open main stent units 5 10396 as the end support body of the main stent graft 1, which can avoid insufficient radial support force and avoid damage to blood vessels caused by high-strength alloy closed main stent unit 3 10393 or high-ductility alloy closed main stent unit 10394 (caused by The support force is too high, making it difficult to fit the natural curvature of normal blood vessels, increasing the risk of vascular damage); the main stent graft 1 body away from the branch stent graft 2 uses a high-strength alloy closed main stent unit 2 1037, a high-strength alloy open main stent unit 3 1038, and a high-ductility alloy open main stent unit 1039 to achieve a hybrid differentiated radial support performance regional distribution, which not only meets the demand for differentiated support performance in different areas of the vascular cavity environment, but also greatly improves the stability of the branched balloon-expandable stent graft system 100, and avoids the displacement of the main stent graft 1 affecting the protection of the internal iliac artery blood flow by the branch stent graft 2. For another example, Figure 5 , a branched balloon-expandable covered stent system 100, its branch covered stent 2 has relatively uniform radial support performance along its length direction, and its main covered stent 1 performs differentiated radial support performance along the length direction of the main body, for example, the high-ductility alloy open main stent unit 2 10391 can adapt to the contraction and relaxation changes of the blood vessel wall due to the impact of blood flow pulses, the high-strength alloy open main stent unit 4 10392 serves as a transition section to avoid local stress concentration in the main tube-shaped coating 102, the high-strength alloy closed main stent unit 3 10393 can provide favorable support to the blood vessel cavity to avoid collapse, and the support performance of the high-ductility alloy closed main stent unit 10394 is weaker than that of the front and rear main stent units, so that the main tube-shaped coating 102 presents a micro-undulating structure, which effectively increases the limit and prevents displacement.

[0066] In some embodiments, the main tubular covering 102 has a mixed set of annealed and non-annealed stent units.

[0067] In some specific embodiments, such as Figures 11 to 14As shown, the stent units serving as the main support skeleton of the main stent graft 1 can have various shapes and structures. For example, the corrugated open metal ring 1031 can be an annealed alloy ring or a non-annealed alloy ring; the open main stent unit 1033 with an opening to avoid the support rod 10332, the support rod 10331 of which can also be annealed; the high-strength alloy closed main stent unit 1032 with a connecting rod 10322, the support rod 10321 of which can also be annealed; the high-strength alloy closed main stent unit 3 10393 and the high-strength alloy closed main stent unit 4 10395 without a connecting rod, can also be annealed, so as to achieve a mixed radial support force value of the main stent graft 1 along its length.

[0068] In some specific embodiments, the closed stent unit in the middle section is made of cobalt-chromium alloy.

[0069] In some specific embodiments, compared to closed stent units with the same geometric dimensions, the two end sections of the main tube-shaped coating 102 are each provided with multiple non-annealed open stent units (e.g., the high-strength alloy open main stent unit 1035 of the first branched balloon-expandable coated stent system and the high-strength alloy open main stent unit 1036 of the second branched balloon-expandable coated stent system). The open stent units can reduce the radial support force of the two end sections, facilitate adhesion to the normal blood vessel wall, and reduce irritation to the normal blood vessel. It can be understood that: under the same conditions (all annealed and with the same geometric dimensions), the radial support force value of the open stent unit is less than that of the closed stent unit; the radial support force value of the non-annealed open stent unit is greater than that of the annealed open stent unit; and the distribution of non-annealed open stent units between annealed open stent units (or the distribution of non-annealed open stent units between annealed closed stent units) can also differentiate the radial support force value of the main coated stent 1 along the length direction.

[0070] In some specific embodiments, a main balloon 4 and a branch balloon 4 are also included; the main balloon 4 is used to be installed in the main coated stent 1, and by expanding the main balloon 4, the main coated stent 1 can be expanded and attached to the main blood vessel; the branch balloon 4 is used to be installed in the branch coated stent 2, and by expanding the branch balloon 4, the branch coated stent 2 can be expanded and attached to the branch blood vessel.

[0071] In some specific embodiments, the opening 101 is a circular or elliptical opening with a diameter of 3-5 mm.

[0072] The branched balloon-expandable covered stent system 100 provided in this embodiment can be used to treat vascular diseases with branched blood vessels such as the common iliac artery and the external iliac artery.

[0073] In some specific embodiments, such as Figure 15 As shown, the main stent graft 1 and branch stent graft 2 of the branched balloon-expandable stent graft system 100 are compressed and gripped on balloon 4 of a balloon delivery system and delivered into the target blood vessel lumen. The balloon delivery system then transforms from an undeployed state 601 to an expanded state 602, thereby releasing the main stent graft 1 and branch stent graft 2 loaded on balloon 4. The main stent graft 1 and branch stent graft 2 are released in a controlled manner by controlling the degree of inflation and expansion of balloon 4. In the post-stent graft release state 603, balloon 4 deflates and retracts for withdrawal from the patient's body.

[0074] Example 2

[0075] This embodiment provides a method for preparing a branched balloon-expandable stent graft system 100 in embodiment 1, comprising the following steps: obtaining a branched stent graft, the branched stent graft comprising a main stent graft 1 and a branch stent graft 2, both of which are balloon-expandable stent grafts 4; the branch stent graft 2 is fixedly connected to the side wall of the main stent graft 1, and the inner cavity of the branch stent graft 2 is connected to the inner cavity of the main stent graft 1. The main stent graft 1 has a mixed radial support performance (radial support force value) along its length, and the branch stent graft 2 has a relatively uniform radial support performance (radial support force value) along its length.

[0076] In some specific embodiments, the main coated stent 1 and the branch coated stent 2 are obtained separately; the method for obtaining the main coated stent 1 includes: cutting the alloy tube to obtain multiple stent units, processing an opening 101 on the coating, heat shrinking or bonding the coating to the stent unit; and fixing the branch coated stent 2 to the opening 101 of the main coated stent 1.

[0077] In some specific embodiments, the processing method of the opening 101 includes: cutting the opening 101 on the tubular coating of the main coated stent 1 by laser cutting; and plasma treating the edge of the opening 101 to reduce damage to the blood vessel caused by the sharp edge.

[0078] In some specific embodiments, the branch unit is obtained by cutting the alloy tube.

[0079] In some embodiments, the membrane is an expanded polytetrafluoroethylene (ePTFE) membrane.

[0080] In some specific embodiments, after the branched covered stent is prepared, it is inserted into an elastic sleeve and pressed onto the balloon 4 to perform radial support force, wall adhesion and anti-unloading tests.

[0081] Example 3

[0082] like Figures 16 to 22 As shown, this embodiment provides a balloon expansion stent delivery system, including 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 a stent 1000, wherein the stent 1000, 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 filled 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 sleeved on the balloon; the radially contracted / compressed / unexpanded stent 1000 can be removably sleeved on the elastic sleeve 3. The elastic sleeve 3 can provide a relatively concave elastic carrier for the stent 1000, so that the stent 1000 can be tightly loaded / clamped on the balloon-expandable stent delivery system (delivery system), that is, the stent 1000 can be concave to a certain extent in the outer wall of the elastic sleeve 3. When loading is completed, the stent 1000 will have a radial rebound of 0.1 to 0.2 mm. At this time, the part of the elastic sleeve 3 that is concave under the action of the stent 1000 can also have an appropriate rebound, so that the stent 1000, the elastic sleeve 3, and the balloon 4 can have better contact, ensuring sufficient friction between the stent 1000, the elastic sleeve 3, and the balloon 4. When the stent 1000 is withdrawn from the delivery sheath, the longitudinal displacement and shortening of the stent 1000 can be reduced; when the balloon 4 expands, the stent 1000 will expand radially. Due to the friction between the elastic sleeve 3 and the stent 1000, the longitudinal displacement and shortening of the stent 1000 during the expansion process are reduced. The stent 1000 is a non-self-expanding stent (including but not limited to a balloon-expandable stent and a balloon-expandable covered stent); the support frame structure of the non-covered balloon-expandable stent can be an existing conventional stent structure or the structure of the present embodiment. Figure 13 The stent frame in the balloon-expandable stent graft can be the main stent graft 1 (or sub-stent graft 2) provided in this embodiment, or a conventional stent graft. It is understood that the balloon-expandable stent delivery system can also be without the elastic sleeve 3; for example, in some application scenarios where a non-stent graft is used (or where a miniaturized outer profile is required in the unfolded state), the balloon-expandable stent delivery system allows for the elastic sleeve 3 to be omitted.

[0083] In some specific embodiments, such as Figure 15As shown, the balloon-expandable stent delivery system can be expanded from an undeployed state 601 having an undeployed diameter to an expanded state 602 having an expanded diameter. Figure 17 As shown, in the balloon-expandable stent delivery system in the undeployed state, the stent 1000 is a coated stent and is constructed 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 (first annular stent 210, second annular stent 220, third annular stent 230, and fourth annular stent 240). The prestressed pleated structures 1300 are spaced apart along the circumference of the stent 1000 and spaced apart along the longitudinal direction of the stent 1000. Figure 16 As shown, the stent 1000 is a non-self-expanding stent (including but not limited to a balloon-expandable stent and a balloon-expandable covered stent), and 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 stent 1000, or higher than the height level of the end of the stent 1000) to form a pillow structure 5 (pillow); the length between the two ends of the stent 1000 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 proximal end 430 of the balloon catheter) can extend relative to the edge of the end of the stent 1000 to form a pillow structure 5 (pillow).

[0084] 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 common (or commercially available) balloon catheter; that is, the stent 1000 on the balloon catheter has a prestressed corrugated structure 1300, or the balloon has a pillow structure 5.

[0085] In some specific embodiments, such as Figures 17 to 19As shown, in a balloon-expandable stent delivery system, a coated stent 1000 in an undeployed state is provided with a plurality of longitudinally extending folds 1301 formed by prestressing. Typically, a fold 1301 extends from one end of a ring-shaped stent strut to the gap between the struts of another ring-shaped stent; for example, a fold 1301 extends from one end of a first strut 2101 of a first ring-shaped stent 210 to the gap between a first strut 2201 and a second strut 2202 of a second ring-shaped stent 220. It will be appreciated that, like the folds of origami, the folds of the folds 1301 can enhance the longitudinal compression resistance compared to a flat coating (e.g., a relatively flat tubular coating surface 111), thereby enhancing the stent 1000's resistance to shortening. Typically, the dimension of a single fold 1301 near the distal end 103 of the stent 1000 is smaller than the dimension of the end farther from the distal end 103. During the deployment of the balloon-expandable stent delivery system, the pleated structure 1301 can inhibit the longitudinal shortening of the stent graft 1000 .

[0086] In some specific embodiments, such as Figure 16 、 Figure 20 and Figure 21 As shown, the balloon 4 in the unexpanded state has a pillow structure 5. Figure 16 As shown, gas or liquid is pre-stored in the cavity of the end portion of the balloon 4 (near the distal end 401 or the proximal end 402 of the balloon), causing the end portion of the balloon 4 to slightly bulge / protrude to form a pillow structure 5. Typically, when traversing a sheath channel or a vascular lumen constructed using the percutaneous Seldinger puncture technique, the pillow structure 5 of the balloon-expandable stent delivery system is squeezed and deformed by the sheath wall or the 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 stent 1000, lifting the balloon wall in this area and moving the balloon inner wall 403 away from the balloon catheter body 420. The balloon outer wall 404 exerts a force on the inner wall of the elastic sheath 3, dynamically compensating for the force between the inner wall of the stent graft 1000 and the outer wall of the elastic sheath 3 (or filling a newly created gap between the inner wall of the stent graft 1000 and the outer wall of the elastic sheath 3), thereby preventing the stent graft 1000 from becoming ungrafted.

[0087] In some specific embodiments, during the process of the balloon-expandable stent delivery system delivering the stent 1000 into the target blood vessel lumen, the pillow structure 5 of the balloon 4 can inhibit the stent graft 1000 from being detached from the balloon-expandable stent delivery system.

[0088] In some specific embodiments, the present embodiment further provides a delivery system for delivering an implant (including but not limited to a balloon-expandable stent and a balloon-expandable covered stent) into a lumen of a human body; the delivery system comprises a balloon catheter and an implant; the balloon catheter comprises a balloon 4 and a balloon catheter body 420; the balloon 4 is fixedly connected and communicated with the balloon catheter body 420 so that the balloon 4 can be filled and supported; the implant is sheathed / loaded / deployed / configured on the balloon 4 of the balloon catheter (for example Figure 15 and Figure 16 Configuration of the middle stent 100 and the balloon 4); Figure 15 As shown, the delivery system can be deployed from an undeployed state 601 having an undeployed diameter to a deployed state 602 having an expanded diameter; Figure 16 and Figure 20 As shown, in the undeployed state 601, the balloon 4 has a pillow structure 5. The pillow structure 5 is partially deployed on the balloon 4, for example, at one end, at both ends, or between the two ends of the balloon. The pillow structure 5 can also be deployed throughout the balloon 4. The pillow structure 5 is a structure that has support, pressure relief, or protection functions similar to an air pillow. It protects or supports the target object through flexible support, pressure redistribution, or a closed air cavity cushioning mechanism.

[0089] Furthermore, in the undeployed state 601, gas or liquid is pre-stored / injected / retained within the balloon lumen to form a pillow structure 5 (pillow). The amount of gas or liquid in the pillow structure 5 (in the undeployed state 601) is less than 50% of the total amount required to fill the balloon (in the deployed state 602). For example, if 20 ml of liquid is required to fill the balloon, the volume of liquid in the pillow structure 5 is less than 10 ml. In some specific application scenarios, the amount of gas or liquid in the pillow structure 5 is 0.01% to 20% or 1% to 30% of the total amount required to fill the balloon. Alternatively, the amount may be 0.1%, 2%, 5%, 8%, 10%, 13%, 15%, 19%, 25%, 28%, 31%, 35%, 40%, 45%, or any value less than 50%.

[0090] Furthermore, the balloon catheter proximal end 430 of the balloon catheter body 420 includes a single-way or multi-way Luer connector, and the balloon 4 can be inflated through the interface of the Luer connector.

[0091] Furthermore, the balloon catheter tube body 420 also includes a component with a valve function, so that the liquid or gas in the pillow structure 5 (pillow) can be temporarily sealed / reserved.

[0092] Furthermore, the balloon wall can be multi-layered; or the balloon wall has a cavity (or interlayer cavity) that can be constructed into a pillow structure 5; the interlayer cavity deployed in the balloon wall can be single or multiple, and can be evenly distributed or irregularly distributed.

[0093] Furthermore, the balloons can be nested in a Russian doll pattern (coaxially or non-coaxially nested), or can be axially spaced. The pillow structure 5 can be deployed in one or more of these axially spaced balloons.

[0094] 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 branched, balloon-expandable stent graft system, characterized by: It includes a main coated stent and a branch coated stent, both of which are balloon-expandable coated stents; the branch coated stent is fixedly connected to the side wall of the main coated stent, and the inner cavity of the branch coated stent is connected to the inner cavity of the main coated stent; the main coated stent is used to be placed in the main blood vessel, and the branch coated stent is used to be placed in the branch blood vessel of the main blood vessel; the main coated stent has a mixed radial support performance along its length; the branch coated stent has a relatively uniform radial support performance along its length.

2. The branched balloon-expandable stent graft system according to claim 1, characterized in that: An opening is provided in the middle of the side wall of the main stent graft, and the branch stent graft is fixedly connected to the opening of the main stent graft.

3. The branched balloon-expandable stent graft system according to claim 1, characterized in that: An opening is provided at one end of the side wall of the main stent graft, and the branch stent graft is fixedly connected to the opening of the main stent graft.

4. The branched balloon-expandable stent graft system according to claim 2 or 3, characterized in that: The outer side wall of the main stent graft at the periphery of the opening is coated with antithrombotic drugs and biocompatible substances, and the outer side wall of the branch stent graft at the periphery of the opening is coated with antithrombotic drugs and biocompatible substances.

5. The branched balloon-expandable stent graft system according to claim 2 or 3, characterized in that: The main stent graft comprises a main stem graft and a plurality of main stent units sequentially arranged along the length direction of the main stem graft; the main stem graft is provided with the opening; and at least one open stent unit is provided on both sides of the opening.

6. The branched balloon-expandable stent graft system according to claim 2 or 3, characterized in that: The branch coated stent comprises a branch tubular coating and a plurality of branch stent units sequentially arranged along the length direction of the branch tubular coating; each of the branch stent units is a closed stent unit.

7. The branched balloon-expandable stent graft system according to claim 6, characterized in that: The material of each branch bracket unit is flexible metal or cobalt-chromium alloy.

8. The branched balloon-expandable stent graft system according to claim 6, characterized in that: Each of the branch support units is an annealed support.

9. The branched balloon-expandable stent graft system according to claim 5, characterized in that: The plurality of main support units between the tube section of the main tube-shaped covering with the opening and the tube end section of the main tube-shaped covering are all closed support units.

10. The branched balloon-expandable stent graft system according to claim 1, characterized in that: It also includes a main balloon and a branch balloon; the main balloon is used to be sleeved inside the main coated stent, and the main coated stent can be expanded and attached to the main blood vessel by expanding the main balloon; the branch balloon is used to be sleeved inside the branch coated stent, and the branch coated stent can be expanded and attached to the branch blood vessel by expanding the branch balloon.

11. A method for preparing the branched balloon-expandable stent graft system according to any one of claims 1 to 10, characterized in that: The method includes the following steps: obtaining a branch-type coated stent, wherein the branch-type coated stent includes the main coated stent and the branch coated stent, and both the main coated stent and the branch coated stent are balloon-expandable coated stents; the branch coated stent is fixedly connected to the side wall of the main coated stent, and the inner cavity of the branch coated stent is connected to the inner cavity of the main coated stent; the main coated stent has a mixed radial support performance along its length direction, and the branch coated stent has a relatively uniform radial support performance along its length direction.

12. The branched balloon-expandable stent graft system according to claim 11, characterized in that: The main coated stent and the branch coated stent are obtained separately; the method for obtaining the main coated stent comprises: cutting the alloy tube to obtain a plurality of stent units, processing openings on the coating, heat shrinking or bonding the coating to the stent units; and fixing the branch coated stent to the opening of the main coated stent.

13. The branched balloon-expandable stent graft system according to claim 12, characterized in that: The processing method of the opening includes: cutting the opening on the tubular coating of the main coating stent by laser cutting; and performing plasma treatment on the edge of the opening.

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