Balloon-expandable stent graft for aortic coarctation

Abstract

The application provides an aorta coarctation special balloon dilatation type auxetic structure partition stent, which comprises a framework and a covering film, the framework comprises an auxetic support area and two compliant areas, the auxetic support area is arranged between the two compliant areas, and the covering film is arranged on the auxetic support area and the compliant areas respectively; the auxetic support area comprises at least two circles of auxetic units, the at least two circles of auxetic units are arranged in the axial direction, and adjacent two circles of the auxetic units are connected, the auxetic unit comprises a plurality of polygonal meshes arranged in the circumferential direction, the polygonal mesh has a pair of concave corner portions, and the inside of at least part of the polygonal meshes is provided with a reinforcing ring, the reinforcing ring is connected with the pair of concave corner portions through reinforcing wires, and the geometric adaptability to a diseased blood vessel is improved.

Description

Technical Field

[0001] This invention relates to the field of covered stent technology, and more particularly to a balloon-expandable pleural stent with a specific structure for aortic coarctation. Background Technology

[0002] With the development of interventional techniques, balloon dilatation stent implantation has become an important method for treating aortic coarctation. The procedure is as follows: a balloon delivery system containing a stent is delivered to the aortic coarctation lesion using interventional techniques; fluid (such as contrast agent) is injected into the balloon through the balloon catheter, causing the balloon to inflate and apply radial force to the stent encased in it, forcing the stent to undergo plastic deformation and expand until it adheres to and opens the narrowed blood vessel segment; finally, the balloon is depressurized and withdrawn, and the expanded stent is permanently implanted to maintain blood flow.

[0003] However, the existing stents upon which this technology relies (represented by the Cheatham-Platinum stent) have inherent limitations in their structural design. These stents are typically cylindrical with a uniform cross-section and a monolithic, uniform mesh framework. This fundamentally contradicts the typical hourglass-shaped pathological anatomy of aortic coarctation (i.e., narrow in the middle and relatively normal at both ends). When the balloon inflates uniformly, the cylindrical stent is forced to expand synchronously throughout its entire length, failing to provide differentiated support and apposition to the narrowed and normal segments. This geometric and mechanical mismatch results in severely uneven stress distribution between the stent and the vessel wall, leading to poor apposition. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a balloon-expandable sectional stent with aortic coarctation-specific structure, which improves the geometric fit with diseased blood vessels.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A balloon-expandable, plethysmogenic, zoned stent for aortic coarctation includes a framework and a covering. The framework comprises a plethysmogenic support zone and two compliant zones, with the plethysmogenic support zone spaced between the two compliant zones. The covering covers the plethysmogenic support zone and the compliant zones respectively.

[0007] The expansion support area includes at least two rings of expansion units, which are arranged axially and adjacent rings of expansion units are connected. Each expansion unit includes a plurality of polygonal grids arranged circumferentially, and each polygonal grid has a pair of concave corners.

[0008] At least a portion of the polygonal mesh has a reinforcing ring inside, and the reinforcing ring is connected to a pair of concave corners by reinforcing wires.

[0009] In a preferred embodiment, the polygonal mesh includes:

[0010] The first week to the side;

[0011] The second week towards the edge;

[0012] Two axial edges are respectively connected between the first circumferential edge and the second circumferential edge, and the middle part of both axial edges is recessed into the polygonal mesh to form a pair of concave corners.

[0013] In the same circle of the expansion unit, two adjacent polygonal meshes are connected by a first circumferential edge and a second circumferential edge.

[0014] In a preferred embodiment, two adjacent expansion units are connected by the axial edges of a polygonal mesh, and the polygonal meshes of two adjacent units are staggered in the circumferential direction.

[0015] In a preferred embodiment, each of the polygonal grids has a reinforcing ring inside.

[0016] In a preferred embodiment, all polygonal grids of one ring of the expansion unit are provided with reinforcing rings, while all polygonal grids of the adjacent ring of the expansion unit are not provided with reinforcing rings.

[0017] In a preferred embodiment, the multiple-turn expansion units are spaced apart along the axial direction, and the polygonal grids of adjacent turns are arranged in a one-to-one correspondence in the circumferential direction and connected by connecting wires.

[0018] In a preferred embodiment, the two ends of the connecting wire are respectively fixed to the concave corners of the corresponding polygonal grids on two adjacent tensioning units.

[0019] In a preferred embodiment, the pair of concave corner portions are circumferentially staggered, and the reinforcing wire is tangentially connected to the reinforcing ring.

[0020] In a preferred embodiment, the compliant zone includes at least two wavy support rings, with adjacent wavy support rings connected to each other by crests and troughs.

[0021] In a preferred embodiment, a developing mark structure is provided at the crest of the outermost wavy support ring;

[0022] And / or, a development mark structure is provided at the connection between the first circumferential edge and the axial edge;

[0023] And / or, a developing mark structure is provided at the connection between the reinforcing wire and the concave corner portion.

[0024] Compared with existing technologies, this technical solution has the following advantages:

[0025] Traditional stents (such as the CP stent) can shorten axially by up to 20% during expansion. Physicians need to estimate this shortening for precise positioning, which can easily lead to stent placement deviation and accidental coverage of important branches such as the left subclavian artery. This invention employs a polygonal grid and reinforcing ring design, maintaining a relatively stable axial length during expansion. This significantly reduces the difficulty of the procedure and the risk of accidental coverage of branch vessels, thus improving the safety of interventional treatment.

[0026] The stent employs a zoned structural design consisting of a central tensile support zone and two compliant zones at both ends. The tensile support zone uses a closed-loop structure, providing strong radial support to counteract vascular rebound and effectively prevent restenosis. The compliant zones use an open-loop, wave-shaped structure, giving the stent excellent flexibility and bending adaptability, allowing it to perfectly conform to the physiological curvature of the aortic arch. This resolves the traditional dilemma of sacrificing both support strength and flexibility, ensuring effective dilation of the stenotic segment while reducing rigid damage to normal vessel segments, thus lowering the risk of pseudoaneurysms and true aneurysms.

[0027] The compliant zones at both ends of the stent are designed with a funnel-shaped, gradually expanding structure. Combined with a phased, segmented expansion approach, this allows for gentle apposition and anchoring of the compliant zones to the normal vessel wall during the initial expansion phase. This pre-anchoring, post-treatment expansion sequence effectively prevents stent displacement or even ejection due to blood flow impact or balloon compression in cases of severe stenosis, providing greater operational stability and success rates for the treatment of complex, high-risk cases.

[0028] The stress distribution is optimized by using a polygonal grid in the tensile support zone in conjunction with an internal reinforcing ring. This structure can withstand cyclic loads more evenly, thereby significantly reducing the risk of stent fracture due to fatigue after long-term implantation, and is expected to significantly reduce the fracture rate from 10-20% of existing products.

[0029] Unlike traditional stents that expand the entire stent simultaneously, this invention utilizes the low stiffness at both ends and high stiffness in the middle, allowing it to be used in conjunction with staged balloon dilation technology to naturally achieve progressive dilation in sections, starting with the ends and then moving to the middle. This dilation mode better matches the hourglass-shaped anatomical characteristics of aortic coarctation, enabling more precise differentiated support, improving apposition to the vessel wall, and potentially reducing the risk of damage from excessive dilation of the normal segment of the vessel in a single procedure. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the aortic coarctation-specific balloon-expandable plethysmoid stent with zoned structure described in this invention;

[0031] Figure 2 This is a schematic diagram of the structure of the first embodiment of the expansion unit described in this invention;

[0032] Figure 3 This is a schematic diagram of the structure of the second embodiment of the expansion unit described in this invention;

[0033] Figure 4 This is a schematic diagram of the structure of the third embodiment of the expansion unit described in this invention;

[0034] Figure 5 This is a schematic diagram of the polygonal mesh structure described in this invention;

[0035] Figure 6 This is a schematic diagram illustrating the use of the aortic coarctation-specific balloon-expandable pleural stent with a zonal structure described in this invention.

[0036] In the diagram: 100 skeleton, 110 tensile support area, 111 tensile unit, 111a polygonal mesh, 111a0 concave corner, 111a1 first circumferential edge, 111a2 second circumferential edge, 111a3 axial edge, 111a31 first axial edge, 111a32 second axial edge, 111b reinforcing ring, 111c reinforcing wire, 111d connecting wire, 120 compliant area, 121 wavy support ring, 200 coating, 300 radiopaque marking structure, 400 metal wire, 500 balloon. Detailed Implementation

[0037] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0038] First Embodiment

[0039] Please refer to Figures 1 to 4 An embodiment of the present invention provides a balloon-expandable pleural sectional stent for aortic coarctation, comprising a skeleton 100 and a covering 200. The skeleton 100 includes a pleural support region 110 and two compliant regions 120, wherein the pleural support region 110 is spaced between the two compliant regions 120, and the covering 200 covers the pleural support region 110 and the compliant region 120 respectively.

[0040] The expansion support area 110 includes at least two rings of expansion units 111, which are arranged axially and adjacent rings of expansion units 111 are connected. The expansion unit 111 includes a plurality of polygonal grids 111a arranged circumferentially, and the polygonal grids 111a have a pair of concave corners 111a0.

[0041] At least a portion of the polygonal mesh 111a has a reinforcing ring 111b inside, and the reinforcing ring 111b is connected to a pair of concave corner portions 111a0 by reinforcing wires 111c.

[0042] The tensile support zone 110 and the compliant zone 120 are structurally spaced and partitioned, enabling partitioned expansion of the stent. The tensile support zone 110, with its polygonal grid 111a, reinforcing rings 111b, and reinforcing wires 111c, forms a strong support structure configured to conform to the narrowed vessel wall in aortic coarctation. The compliant zone 120, with its excellent flexibility, is configured to conform to the narrowed vessel wall in the stenotic segment. This partitioned design, with strong support in the middle and high compliance at both ends, perfectly matches the pathophysiological characteristics of aortic coarctation.

[0043] like Figure 2 and Figure 5 As shown, the polygonal mesh 111a is hexagonal, and its outline includes a first circumferential edge 111a1, a second circumferential edge 111a2, and two axial edges 111a3.

[0044] The first circumferential edge 111a1 and the second circumferential edge 111a2 are parallel to each other and arranged circumferentially along the support. Two axial edges 111a3 are arranged axially along the support and are respectively connected between the first circumferential edge 111a1 and the second circumferential edge 111a2. Each axial edge 111a3 further includes a first axial edge 111a31 and a second axial edge 111a32 that are joined in the middle, and the joint between the two is concave inward to form the concave corner portion 111a0.

[0045] like Figure 2 As shown, in the same circle of the expansion unit 111, two adjacent polygonal grids 111a are connected by a first circumferential edge 111a1 and a second circumferential edge 111a2.

[0046] Specifically, the first circumferential edge 111a1 of one of the polygonal meshes 111a is connected to the second circumferential edge 111a2 of the adjacent polygonal mesh 111a. This connection method allows multiple polygonal meshes 111a to be connected end to end along the circumferential direction, together forming a single loop of the expansion unit 111.

[0047] Furthermore, multiple expansion units 111 are arranged along the axial direction of the support, and any two adjacent expansion units 111 are connected. All polygonal grids 111a contain reinforcing rings 111b. That is, each polygonal grid 111a in the expansion support region 110 integrates an independent reinforcing ring 111b structure, thus forming a closed-loop structure for the expansion support region 110. This ensures that the expansion support region 110 has extremely high support force and compression resistance, enhancing the integrity and structural stability of the expansion support region 110 after implantation, effectively resisting retraction of the stenotic segment, and effectively preventing breakage.

[0048] The reinforcing wire 111c is connected to the reinforcing ring 111b and the concave corner portion 111a0 by welding.

[0049] In the prior art, after the balloon inflates the stent, the grid of the stent is opened up, and the axial dimension of the stent is shortened, which poses a challenge to positioning. This embodiment overcomes this defect by introducing a tensile structure. Specifically, in the polygonal grid 111a, a pair of concave corner portions 111a0 are connected to the internal reinforcing ring 111b by reinforcing wires 111c, forming a stable triangular tie system.

[0050] When the balloon 500 applies a radial expansion force, the first circumferential edge 111a1 and the second circumferential edge 111a2 are forced to move away from each other. This movement drives the concave corner portion 111a0 to produce a hinge-like unfolding action, gradually straightening it. This unfolding process provides radial support while simultaneously generating compensatory extension in the axial direction, effectively counteracting the inherent axial shortening tendency of traditional mesh structures during expansion, thus enabling the entire stent to maintain extremely high length stability during expansion (i.e., achieving a tensile expansion effect).

[0051] It is worth noting that the pair of concave corner portions 111a0 are staggered in the circumferential direction, which makes the two reinforcing wires 111c parallel after being tangentially connected to the reinforcing ring 111b. Moreover, their extension direction is basically consistent with the first circumferential edge 111a1 and the second circumferential edge 111a2, and is parallel to the axial direction of the bracket.

[0052] Based on this spatial structure, during the balloon expansion driving the deployment of the pair of concave corner portions 111a0, the parallel reinforcing wires 111c are primarily stretched along their axial direction. Simultaneously, the reinforcing ring 111b is synchronously pulled by the reinforcing wires 111c on both sides, resulting in coordinated adaptive elastic deformation. For example, the reinforcing ring 111b may rotate, and during the straightening of the pair of concave corner portions 111a0, the two reinforcing wires 111c connected to the reinforcing ring 111b remain on the same straight line. This linkage mechanism of axial stretching of the reinforcing wires 111c and coordinated deformation of the reinforcing ring 111b provides guidance and constraint for the deployment process of the concave corner portions 111a0, ensuring the stability of the expansion behavior and thus significantly improving the morphological stability and mechanical reliability of the stent during expansion.

[0053] like Figure 2 As shown, the two adjacent rings of expansion units 111 are connected by the axial edge 111a3 of the polygonal mesh 111a, and the two adjacent rings of polygonal mesh 111a are staggered in the circumferential direction.

[0054] Specifically, the first axial edge 111a31 of a certain polygonal mesh 111a in one ring of expansion unit 111 is connected to the second axial edge 111a32 of the corresponding polygonal mesh 111a in the adjacent ring of expansion unit 111, so that the polygonal meshes 111a of the two adjacent rings are arranged in an alternating pattern in the circumferential direction to form a closed-loop expansion support area 110.

[0055] like Figure 1 As shown, the compliant zone 120 includes at least two wavy support rings 121, with adjacent wavy support rings 121 connected to each other by crests and troughs. This wavy design gives the compliant zone 120 extremely high flexibility and bending adaptability, allowing it to conform to the physiological curvature of the aortic arch like a flexible tube, effectively avoiding excessive rigid pressure on the vessel wall, thereby significantly reducing the risk of stent damage to the vessel.

[0056] In this embodiment, there are two wavy support rings 121: an outer wavy support ring 121 and an inner wavy support ring 121. The outer and inner wavy support rings 121 are arranged along the axial direction of the support. The inner wavy support ring 121 is positioned closer to the tension support area 110, while the outer wavy support ring 121 is positioned further away from the tension support area 110. The troughs of the outer wavy support ring 121 and the crests of the inner wavy support ring 121 can be connected by spot welding, 400° wire winding, or other methods.

[0057] Furthermore, the diameter of the outer support ring 121 is designed to be larger than the diameter of the inner support ring 121, thereby giving the compliant zone 120 an overall funnel-shaped, gradually expanding structure. This funnel-shaped structure avoids the right-angled edges of the straight stent's end, significantly reducing the local cutting effect and mechanical stimulation on the blood vessel wall.

[0058] like Figure 1 As shown, the membrane 200 is made of expanded polytetrafluoroethylene (ePTFE) or polyurethane film and is tightly attached to the outer surface of the skeleton 100. It is fixed by a few dotted sutures at both ends of the flared opening and in the middle using medical sutures, ensuring complete closure without restricting subsequent expansion.

[0059] like Figure 5 and Figure 6 As shown, to further optimize the visibility of the stent under X-rays and achieve precise intraoperative positioning and accurate postoperative assessment, the stent is provided with multiple radiopaque marker structures 300. These markers are made of high-density, high atomic number materials such as platinum-iridium alloy (Pt-Ir) rings, gold (Au) dots, or tantalum (Ta) dots, and are firmly fixed to the designated positions by laser welding, embedding, or medical adhesives.

[0060] The development mark structure 300 is located in at least one of the following positions, which together constitute a complete development navigation system:

[0061] Located at the crest of the outermost wavy support ring 121 within the compliant zone 120. This marker is used to clearly indicate the proximal and distal boundaries of the stent during deployment, assisting the operator in precisely anchoring the stent to the target vessel segment and effectively avoiding accidental coverage of important branch openings such as the left subclavian artery.

[0062] Located within the expansion support region 110, at the junction of the first circumferential edge 111a1 and the axial edge 111a3 of the polygonal mesh 111a. This marking helps the surgeon observe the symmetry and uniformity of the expansion structure in real time during balloon dilation, ensuring that the stent forms as designed.

[0063] Located within the expansion support region 110, at the connection point between the reinforcing wire 111c and the concave corner portion 111a0. Since the distance between these connection points changes linearly with the radial expansion of the stent, the actual expansion diameter of the stent can be quantitatively and accurately calculated by measuring the distance between these marker points during postoperative follow-up imaging examinations, providing an objective basis for assessing the support effect and monitoring the risk of restenosis.

[0064] like Figure 1 As shown, the axial length of the skeleton 100 is 35-80mm, the axial length of the tension support region 110 is 20-50mm, and the axial length of the compliant region 120 is 8-20mm.

[0065] like Figure 1 and Figure 6 The method of using the balloon-expandable pleural pleural stent with sectional graft for treating aortic coarctation is as follows:

[0066] Step 1: Preoperative Planning and Measurement

[0067] Acquire CTA or MRI images of the patient's aorta and perform three-dimensional reconstruction of the aortic coarctation. Measure and record the narrowest diameter of the coarctated segment, the length of the coarctation, and the diameters of the proximal and distal normal vessel segments. Based on the measurements, select the appropriate stent size, typically ensuring that the nominal expanded diameter of the stent is equal to or slightly larger than the diameter of the adjacent normal vessel.

[0068] Step 2: Establishing vascular access and stent delivery

[0069] The patient's femoral artery is percutaneously punctured, and a vascular sheath is inserted. Under guidewire guidance, a stiffened guidewire is passed through the aortic arch and through the narrowed lesion segment. The balloon catheter delivery system pre-loaded with the stent of this invention is advanced into the aorta along the guidewire, and advanced to the narrowed lesion area under X-ray fluoroscopy guidance. At this point, both the stent and the balloon are in a compressed state.

[0070] Step 3: Precise Positioning of the Support

[0071] Under X-ray fluoroscopy, the contrast-enhancing marker structures 300 at both ends and the middle of the stent are observed. The delivery system is adjusted so that the contrast-enhancing marker structure 300 at the proximal end of the stent is positioned within the normal vessel at the proximal end of the narrowed segment, ensuring it is distal to the opening of the left subclavian artery; the contrast-enhancing marker structure 300 at the distal end of the stent is positioned within the normal vessel at the distal end of the narrowed segment. The contrast-enhancing marker structure 300 in the middle of the stent is precisely aligned with the narrowest point of the narrowed lesion. Because the axial shortening rate of the expansion support zone 110 of this invention is extremely low during expansion, the stent can achieve precise "what you see is what you get" positioning without requiring the significant shortening allowance of traditional stents.

[0072] Step 4: Gradual Expansion by Region

[0073] Phase 1: First, contrast agent is injected into the balloon 500 to a low pressure (e.g., 30%-50% of the rated burst pressure). At this time, the "funnel" structure formed by the compliant zones 120 at both ends of the stent expands first due to its low radial stiffness, compliantly adhering to the normal aortic wall at the proximal and distal ends of the narrowed segment, achieving initial anchoring of the stent and effectively preventing stent displacement during subsequent high-pressure expansion.

[0074] Phase Two: Continue increasing the balloon pressure by 500 to the treatment pressure (e.g., reaching or approaching the balloon's rated burst pressure). At this stage, the expansion force primarily acts on the tensile support zone 110 in the middle of the stent. The polygonal grid 111a in this zone expands, and the internal reinforcing rings 111b stretch simultaneously, generating a strong radial support force that powerfully expands and reshapes the calcified or fibrotic aortic constriction ring. During this process, the negative Poisson's ratio effect generated by the tensile structure effectively counteracts axial shortening, maintaining the stent length essentially stable.

[0075] Step 5: Immediate Postoperative Assessment and Instrument Removal

[0076] After achieving satisfactory dilation, 500g of the balloon was deflated, and X-ray fluoroscopy confirmed that the stent was completely adhered to the vessel wall and had a good morphology. The balloon catheter and guidewire were withdrawn. Aortic angiography was performed for follow-up to assess the efficacy, confirming that: the pressure gradient in the stenotic segment had significantly decreased or disappeared; the proximal and distal ends of the stent were tightly adhered to the vessel wall without any poor apposition; and the final stent position was consistent with the pre-deployment positioning, without covering the openings of important branch vessels.

[0077] Step Six: Long-term secondary intervention (applicable to patients in the growth and development stage)

[0078] For children or adolescents in their growth and development stage, if stent stenosis occurs due to vascular growth in the future, secondary balloon dilation can be performed. Because the stent of this invention uses an ePTFE membrane and has flexible ends, it can be safely dilated by inserting a larger diameter balloon again. The expansion support zone 110 in the middle of the stent has sufficient extension reserve, allowing it to be further dilated to the required adult diameter to accommodate vascular growth, thereby avoiding surgical removal of the stent.

[0079] Second Embodiment

[0080] like Figure 3 As shown, the second embodiment of the balloon-expandable plethysmoid sectional covered stent for treating aortic coarctation differs from the first embodiment in that all polygonal grids 111a of one ring of the plethysmoid unit 111 are provided with reinforcing rings 111b inside, while all polygonal grids 111a of the other ring of the plethysmoid unit 111 adjacent to it are not provided with reinforcing rings 111b inside.

[0081] Third Embodiment

[0082] like Figure 4 As shown, the balloon-expandable pleural structure sectional covered stent for treating aortic coarctation in the third embodiment differs from the first embodiment in that the multiple pleural units 111 are spaced apart along the axial direction, and the polygonal grids 111a of adjacent two circumferential rings are arranged in a one-to-one correspondence in the circumferential direction and are connected by connecting wires 111d.

[0083] The two ends of the connecting wire 111d are respectively fixed to the concave corner 111a0 of the corresponding polygonal grid 111a on two adjacent tension units 111.

[0084] Fourth embodiment

[0085] This embodiment also provides a method for preparing a balloon-expandable pleural stent with a zoned covered structure for treating aortic coarctation, which mainly includes the following steps:

[0086] Step 1: Preparation of skeleton 100:

[0087] (1) Selection of pipe material: Medical grade 316L stainless steel seamless pipe conforming to ASTM F138 standard or L605 cobalt chromium alloy pipe is selected; the initial outer diameter of the pipe is 4.0mm~6.0mm and the wall thickness is 0.2mm~0.3mm.

[0088] (2) Laser cutting: Using a femtosecond laser cutting machine or a fiber laser cutting machine, the tube is rotated and cut according to the computer-aided design planar unfolding diagram; wherein, a tension support area 110 with a closed middle ring is cut in the middle of the tube, the tension support area 110 is composed of a polygonal grid 111a and a reinforcing ring 111b set inside the polygonal grid 111a; a compliant area 120 is cut at both ends of the tube, the compliant area 120 is composed of a wave-shaped support ring 121; during the cutting process, it is ensured that the reinforcing ring 111b is integrally connected with the frame of the polygonal grid 111a, and the width of the connection point is not less than 0.08mm; and a deformation gap of 0.05mm to 0.1mm is reserved between the reinforcing ring 111b and the frame of the polygonal grid 111a;

[0089] (3) Surface treatment: The cut skeleton 100 is pickled and electrochemically polished; the pickling uses a mixed solution of hydrofluoric acid and nitric acid to remove the heat-affected zone and slag generated by laser cutting; the electrochemical polishing uses a phosphoric acid-sulfuric acid electrolyte to make the surface roughness Ra of the skeleton 100 less than 0.2 μm, and the edges of the skeleton 100 are rounded.

[0090] (4) Heat treatment and shaping: The surface-treated skeleton 100 is fitted into the shaping mold. The two ends of the shaping mold are tapered, and the angle of the tapered angle is 15° to 30°. The shaping mold with the skeleton 100 is placed in a vacuum heat treatment furnace for annealing. For the skeleton 100 made of 316L stainless steel, the heating temperature of the annealing treatment is 1050°C to 1100°C, the holding time is 30 min to 60 min, and rapid water cooling is performed after the holding time is completed.

[0091] Step 2, Preparation and Assembly of Coating 200:

[0092] (5) Coating and cutting: Select expanded polytetrafluoroethylene film tube with a wall thickness of 0.05mm to 0.1mm and the micropore diameter of the film tube is 30μm; cut the film tube to match the length of the skeleton 100 and leave uncovered areas at both ends to obtain the coating 200.

[0093] (6) Covering and fixing: The cut covering tube 200 is sleeved on the outside of the skeleton 100 and fixed with medical sutures; wherein, in the flared area at both ends of the compliant area 120, a knot is tied and fixed every other wave peak; in the tensile support area 110 of the middle closed loop, point sutures are only made at the vertices of some polygonal grids 111a.

[0094] Step 3: Marker Installation and Final Processing

[0095] (7) Installation of developing marks: Platinum-iridium alloy marking rings are installed at the outermost crests of the bell mouths at both ends of the compliant zone 120, and gold tracer points are installed at the axial midpoint of the tensile support zone 110.

[0096] (8) Pressing and sterilization: The assembled film-coated support is compressed onto the conveying system using a radial presser, and then sterilized with ethylene oxide and vacuum packaged.

[0097] The embodiments described above are only used to illustrate the technical ideas and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The scope of patent application of the present invention should not be limited by these embodiments. That is, any equivalent changes or modifications made in accordance with the spirit disclosed in the present invention still fall within the patent scope of the present invention.

Claims

1. A balloon-expandable pleural stent with a zoned structure specifically for aortic coarctation, characterized in that: The system includes a frame (100) and a covering (200). The frame (100) includes a tensile support region (110) and two compliant regions (120). The tensile support region (110) is spaced between the two compliant regions (120). The covering (200) is applied to the tensile support region (110) and the compliant region (120) respectively. The expansion support area (110) includes at least two rings of expansion units (111), which are arranged axially and adjacent rings of expansion units (111) are connected. The expansion unit (111) includes a plurality of polygonal grids (111a) arranged circumferentially, and the polygonal grids (111a) have a pair of concave corners (111a0). At least a portion of the polygonal mesh (111a) has a reinforcing ring (111b) inside, and the reinforcing ring (111b) is connected to a pair of concave corner portions (111a0) respectively by reinforcing wires (111c); The polygonal mesh (111a) includes: First perimeter edge (111a1); The second week's edge (111a2); Two axial edges (111a3) are respectively connected between the first circumferential edge (111a1) and the second circumferential edge (111a2). The middle part of the two axial edges (111a3) is recessed into the polygonal grid (111a) to form a pair of concave corners (111a0). In the same circle of the expansion unit (111), two adjacent polygonal grids (111a) are connected by a first circumferential edge (111a1) and a second circumferential edge (111a2).

2. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in claim 1, characterized in that, The two adjacent expansion units (111) are connected by the axial edge (111a3) of the polygonal mesh (111a), and the two adjacent polygonal meshes (111a) are staggered in the circumferential direction.

3. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in claim 2, characterized in that, Each of the polygonal grids (111a) has a reinforcing ring (111b) inside.

4. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in claim 2, characterized in that, One of the expansion units (111) has a reinforcing ring (111b) inside all the polygonal grids (111a) inside, while the other expansion unit (111) adjacent to it does not have a reinforcing ring (111b) inside all the polygonal grids (111a).

5. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in claim 1, characterized in that, The multiple-turn expansion units (111) are spaced apart along the axial direction, and the polygonal grids (111a) of adjacent two turns are arranged in a one-to-one correspondence in the circumferential direction and connected by connecting wires (111d).

6. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in claim 5, characterized in that, The two ends of the connecting wire (111d) are respectively fixed at the concave corner (111a0) of the corresponding polygonal grid (111a) on two adjacent tension units (111).

7. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in any one of claims 1 to 6, characterized in that, The pair of concave corner portions (111a0) are circumferentially offset, and the reinforcing wire (111c) is tangentially connected to the reinforcing ring (111b).

8. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in claim 1, characterized in that, The compliant zone (120) includes at least two wavy support rings (121), with adjacent wavy support rings (121) connected to each other by crests and troughs.

9. The aortic coarctation-specific balloon-expandable pleural stent with a zoned structure as described in claim 8, characterized in that, A developing mark structure (300) is provided at the crest of the outermost wave-shaped support ring (121). And / or, a development mark structure (300) is provided at the connection between the first circumferential edge (111a1) and the axial edge (111a3). And / or, a developing mark structure (300) is provided at the connection between the reinforcing wire (111c) and the concave corner portion (111a0).

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