Biodegradable metal intravascular stent and application thereof

Abstract

The invention relates to the technical field of medical apparatus and instruments, and provides a biodegradable metal intravascular stent and application thereof.The biodegradable metal intravascular stent comprises a plurality of main body structure supporting rings; the main body structure supporting rings are transversely and sequentially connected and then longitudinally surround to form a tubular structure, every two adjacent main body structure supporting rings are connected through a plurality of connecting rods arranged at intervals, and each main body structure supporting ring comprises a plurality of main body units connected to form a wavy structure. The design of the non-concentric arc part in the main body unit not only improves the radial supporting force of the stent, but also enables the residual stress to be distributed more uniformly. The design of the three straight rod parts and the two inflection curve parts can better avoid the interference problem generated in the pressing, holding and expanding process of the stent, the connecting rod is of an s-shaped structure, the phenomena that due to bending, a traditional linear connecting rod is uneven in stress in the circumferential direction, the bent inner side unit makes contact, and the bent outer side warps are obviously improved, and the stability of the stent is improved. The flexibility and the compliance of the stent are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular, to a biodegradable metal vascular stent and application thereof, especially to a biodegradable metal vascular stent with high radial support force and application thereof. BACKGROUND

[0002] Cardiovascular disease is one of the main chronic non-communicable diseases threatening human health today. The core problem of this kind of disease is the blood vessel stenosis or occlusion caused by endothelial dysfunction and plaque formation. In order to alleviate the blood vessel stenosis, the vascular stent as an important interventional treatment method has been widely used.

[0003] The stent structure has a great influence on its performance. The radial support force of the stent is derived from the resistance to deformation of its structure when it is subjected to radial pressure. When the blood vessel is narrowed due to atherosclerosis and other diseases, the stent is implanted to prop open the narrowed blood vessel. The radial support force can resist the resilience of the blood vessel wall, maintain the blood vessel in the expanded state, ensure the smooth flow of blood, thereby effectively preventing acute recoil and long-term restenosis of the blood vessel, and optimizing the adhesion of the stent to the blood vessel wall to reduce the risk of thrombosis. If the radial support force is insufficient, the blood vessel wall may collapse again, leading to in-stent restenosis, resulting in treatment failure and restenosis.

[0004] The traditional vascular stent is made of non-degradable alloys (such as stainless steel, cobalt-chromium alloy), which have excellent strength, toughness and fatigue resistance, and can maintain stable mechanical support in the body for a long time. Therefore, the structural design of the vascular stent can fully utilize these high-strength characteristics to achieve a thin stent wall thickness and a complex geometry, so as to optimize the flexibility and deliverability while ensuring sufficient radial support force. However, the current degradable alloys (such as magnesium alloy, zinc alloy) gradually corrode and degrade after being implanted into the body. This means that their mechanical properties (such as strength, elastic modulus) will decrease over time. For degradable stents, the radial support force is a more critical indicator in the design, because the core challenge lies in how to continuously provide sufficient support force during the degradation process to cope with the resilience and remodeling of the blood vessel wall, and avoid collapse during the critical "window period" of blood vessel healing. If the structure of the non-degradable stent is directly used, the stent may quickly lose sufficient radial support force during the degradation process, resulting in blood vessel collapse. Therefore, compared with the structure of the non-degradable stent, the degradable stent needs a thicker wall thickness and wire diameter to maintain a higher radial support force. However, higher wall thickness and wire diameter not only increase the volume of metal implanted into the human body, but also affect the blood vessel. Therefore, for non-degradable alloys, a more special geometric design is needed to provide a higher support force while ensuring a lower thickness and wire diameter, to make up for the change in mechanical properties of the stent material over time, so as to ensure that the effective radial support is maintained even if the material strength gradually decreases, thereby ensuring long-term efficacy and safety.

[0005] Li et al. (Li Y, Wang Y, Shen Z, et al. A biodegradable magnesium alloy vascular stent structure: Design, optimization and evaluation[J]. ActaBiomaterialia, 2022, 142: 402-412.) designed a stent with a smaller cross-section and stronger support, achieving a 38.7% increase in radial support compared to the original sinusoidal stent. Chen et al. (Chen C, Chen J, Wu W, et al. In vivo and in vitro evaluation of a biodegradable magnesium vascular stent designed by shape optimization strategy[J]. Biomaterials, 2019, 221:119414.) designed a stent with uniform stress distribution, avoiding excessive local stress concentration, reducing the high-stress area by 3.44% compared to the original sinusoidal stent. However, the above designs have some shortcomings: the former has a very small distance between the main units in order to ensure high radial support force, and the connecting rod is connected to the side of the main unit, which not only reduces its flexibility, but also causes uneven stress distribution during the gripping expansion process; the latter's U-shaped connecting rod design reduces uneven stress distribution and avoids excessive stress concentration, but the U-shaped connecting rod design of this structure will cause it to warp during the gripping process, damaging the inner wall of the blood vessel, and the design of its protruding unit will hinder blood flow.

[0006] Patent document CN106176003A discloses a vascular stent structure mainly used in stainless steel and cobalt-chromium alloys. This structure is prone to stress concentration. If this structure is used to make vascular stents with biodegradable metals, it will cause the stent to fail prematurely, and the stress distribution will be uneven, leading to uneven degradation and interference problems.

[0007] Patent document CN105596125A discloses a zinc alloy vascular stent with moderate metal coverage, good radial support, and low strain unevenness; patent document CN103110465A discloses a magnesium alloy vascular stent with small compression expansion deformation and good flexibility. However, the former focuses on reducing the uneven stress distribution during compression expansion, but its radial support is not improved, and its connecting rod design reduces the stent's flexibility; the latter's design focuses on reducing compression expansion deformation, but does not significantly improve the support strength.

[0008] Patent document CN106691647A discloses a vascular stent with small plastic deformation during the gripping and expansion process, which reduces the mechanical damage that may be introduced during the deformation process. However, the radial support force of this structure is low; the U-shaped connecting rod design will cause it to warp during the gripping process, damaging the inner wall of the blood vessel, and the design of its protruding unit will hinder blood flow.

[0009] In summary, there is an urgent need for a vascular stent design that features high radial support, low rebound rate, relatively uniform deformation, good flexibility, uniform stress distribution during compression expansion, and minimal impact on blood flow. Summary of the Invention

[0010] To address the shortcomings of existing technologies, the present invention aims to provide a biodegradable metallic vascular stent and its applications.

[0011] A biodegradable metallic vascular stent according to the present invention includes multiple main structural support rings;

[0012] Multiple main structure support rings are connected horizontally in sequence and then longitudinally wrapped to form a tubular structure. Adjacent main structure support rings are connected by multiple spaced connecting rods. Any two adjacent main structure support rings are mirror-symmetrical to each other. Each of the main structural support rings includes multiple main units connected in a wave-shaped structure.

[0013] Preferably, the main body unit includes two first arc sections and three straight rod sections and two bend curve sections arranged between the two first arc sections; The three straight sections are alternately connected to the two curved sections.

[0014] Preferably, one end of the first straight rod is connected to the end of a first arc portion, the other end of the first straight rod is connected to one end of a first bend curve portion, the two ends of the second straight rod are respectively connected to the other end of the first bend curve portion and one end of the second bend curve portion, and the two ends of the third straight rod are respectively connected to the other end of the second bend curve portion and the end of another first arc portion.

[0015] Preferably, the radius of the first inner arc surface or the first outer arc surface of the first arc portion is 0.1-0.5 mm; The length of the straight rod section is 0.1-0.5 mm; The radius of the arc of the bend curve is 0.1 to 0.5 mm.

[0016] Preferably, the first inner arc surface and the first outer arc surface of the first arc portion on each main body unit are not concentric, and the distance between the centers of the corresponding circles of the first inner arc surface and the first outer arc surface of each first arc portion is 0.01-0.05mm.

[0017] Preferably, the connecting rod has an S-shaped structure, including a long straight portion, a short straight portion, and an arc-shaped portion; The two ends of the long straight portion are respectively connected to one end of the two arc-shaped portions, and the other ends of the two arc-shaped portions are respectively connected to one end of a short straight portion and one end of another short straight portion; Among them, the connecting rods of the vascular stent are arranged in a spiral shape in space.

[0018] Preferably, the arcuate portion is U-shaped, and the opening directions of the two arcuate portions are arranged opposite to each other; Both sides of the arc-shaped portion are smooth curves. The connecting rod is connected to the main structure support ring through the second arc portion. The length of the short straight portion is 0.1-0.25mm, and the length of the long straight portion is 0.3-0.6mm. The connection between the main structure support ring and the second arc portion is chamfered.

[0019] Preferably, the outer diameter of the vascular stent is 1-5 mm, the wall thickness is 0.05-0.3 mm, and the length is 10-100 mm; The width of the metal rod of the main unit is 0.1-0.3mm, and the width of the connecting rod (2) is 0.06-0.25mm; Biodegradable metallic vascular stents can adjust the number of main units and connecting rods according to the target expansion size.

[0020] Preferably, the material is a zinc alloy or a magnesium alloy.

[0021] The present invention relates to the application of a biodegradable metal vascular stent in the preparation of a medical device for supporting human cavities.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. In the biodegradable metal scaffold of this invention, the first inner and outer arc surfaces of the first arc portion constituting each main unit are not concentric. This design ensures that the width of the scaffold metal rod at the crests and troughs of the scaffold body is slightly wider than that of the straight rod portion and the bend curve portion, and achieves a uniform transition where "the dimensions at the connection between the arc portion and the bend curve portion are the same, and the width of the metal rod is greatest at the crests and troughs." During the scaffold compression and expansion process, stress concentration is most likely to occur at the crests and troughs of the scaffold body, causing uneven corrosion and fracture. This design allows the scaffold to better disperse the stress concentrated at the crests and troughs, ensuring uniform corrosion. Furthermore, the widening at this point significantly improves the radial support force of the scaffold. Meanwhile, the design does not impede blood flow, avoiding uneven corrosion caused by uneven distribution of shear stress due to blood flow; the design enables the stent to maintain sufficient radial support during the critical window period of vascular remodeling (6-12 months after implantation), effectively resisting vascular elastic recoil and negative remodeling; by eliminating geometric abrupt change points, the problem of accelerated local corrosion caused by stress concentration is solved, ensuring the synchronicity of the degradation process and the integrity of the stent structure.

[0023] 2. The biodegradable metal scaffold in this invention adopts a structure of straight rod section – bent curve section – straight rod section – bent curve section – straight rod section. The design of three straight rod sections and two bent curve sections can better avoid interference problems caused by the scaffold during the compression and expansion process. Through finite element simulation, the optimal structural parameters were simulated by finely adjusting the contours of the arc and bent curve sections, so that the stiffness of the two is matched and they jointly participate in the compression and expansion deformation, giving it excellent radial support performance without limiting its expansion range.

[0024] 3. In this invention, the connecting rods on the support have an "S"-shaped structure, consisting of two second circular arc sections, two arc-shaped sections, and straight sections at both ends of the arc-shaped sections, forming a structure of second circular arc section—short straight section—arc section—long straight section—arc section—short straight section—second circular arc section. The "S"-shaped structure maintains its shape after the support is compressed and expanded, significantly improving the uneven circumferential stress, contact issues on the inner side of the bend, and warping on the outer side caused by the bending of traditional straight connecting rods, greatly improving the flexibility and adaptability of the support. Simultaneously, the connecting rods are evenly connected at the crests and troughs of the main body through chamfering, avoiding stress concentration on one side of the main unit structure during compression and expansion compared to connecting rods connected to the side. The widened crests and troughs also better disperse stress.

[0025] 4. The design of the two arc-shaped parts of the S-shaped structure in this invention allows the connecting rod to better fit the balloon after the stent is gripped. Compared with a straight rod, it can be delivered to the lesion site better and prevent "warping" during transportation. At the same time, the chamfer design of the connection between the connecting rib and the main unit makes the connection between the two smoother, which can effectively reduce the burr phenomenon generated during the laser processing of the stent, effectively improve the laser cutting performance of the stent, and cut a stent with better surface quality and higher integrity.

[0026] 5. The biodegradable metal stent in this invention has been optimized through finite element simulation to obtain the most suitable structural parameters for the biodegradable metal stent. The optimization design of vascular stents faces the complex problem of the relationship between design objectives and design variables. However, traditional clinical or experimental methods cannot reconcile the contradictions between various design requirements, nor can they find a vascular stent design that simultaneously meets multiple design requirements. Current vascular stent design mainly relies on comparative analysis, that is, comparing the performance of several different stent designs and selecting the best one. This "trial and error" method only yields a "comparatively optimal design" among several designs, rather than a "globally optimal design" within the design space, and it also has a long development cycle and high development costs. Finite element simulation can further optimize the microstructure dimensions to take into account multiple performance design requirements of vascular stents, achieving multi-performance optimization design of the stent. By finely adjusting the center distance between the arc portion, straight portion, and the two arc portions at the crest and trough of the main unit, a vascular stent structure design with higher radial support force and smaller plastic strain was obtained, effectively balancing the radial support strength and plastic strain of the stent, resulting in excellent radial support performance and good gripping expansion performance.

[0027] 6. In addition to being used as a vascular stent for the treatment of peripheral and coronary artery stenosis, the stent in this invention can also be used as a biodegradable stent for the treatment of other luminal stenosis, such as esophageal stents, tracheal stents, bile duct stents, pancreatic duct stents, urinary catheter stents, etc., with a wide range of applications and good versatility. Attached Figure Description

[0028] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a three-dimensional structural schematic diagram of the biodegradable metallic vascular stent of the present invention; Figure 2 This is a schematic diagram of the unfolded planar structure of a biodegradable metallic vascular stent. Figure 3 This is a structural diagram of the main unit; Figure 4 This is a schematic diagram of the connecting rod.

[0029] The diagram shows: Main Unit 1; Straight rod section 11; Turning curve section 12; First arc portion 13; Connecting rod 2; Arc-shaped part 21; Long, straight section 22; Second arc portion 23; Short straight section 24; Chamfered edge 25; Main structure support ring 3. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various changes and modifications without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0031] Basic Implementation Example: This invention provides a biodegradable metallic vascular stent, which uses a biodegradable zinc alloy or magnesium alloy. The shape of the biodegradable metallic vascular stent is designed with special repeating structural units to provide the stent with good mechanical properties and a long effective service life, so as to meet the practical requirements of biodegradable vascular stents in clinical practice.

[0032] Specifically, the biodegradable metal vascular stent includes multiple main structural support rings 3, which are connected horizontally in sequence and then longitudinally wrapped to form a tubular structure. Adjacent main structural support rings 3 are connected by multiple spaced connecting rods 2, wherein any two adjacent main structural support rings 3 are mirror-symmetrical to each other.

[0033] Furthermore, each main structure support ring 3 includes multiple main body units 1 connected in a wave-shaped structure. In practical applications, the number of main body units 1 on each main structure support ring 3 is 4 to 16 in the circumferential direction of the vascular stent.

[0034] like Figure 3 As shown, the main body unit 1 includes two first arc sections 13 and three straight rod sections 11 and two bend curve sections 12 arranged between the two first arc sections 13. The center side of the two first arc sections 13 is arranged on both sides of the three straight rod sections 11 and the two bend curve sections 12, that is, the opening directions of the two first arc sections 13 are different.

[0035] like Figure 2 , Figure 3As shown, three straight rod sections 11 are alternately connected to two bend curve sections 12. One end of the first straight rod section 11 is connected to the end of a first arc section 13, and the other end of the first straight rod section 11 is connected to one end of the first bend curve section 12. The two ends of the second straight rod section 11 are connected to the other ends of the first bend curve section 12 and one end of the second bend curve section 12, respectively. The two ends of the third straight rod section 11 are connected to the other ends of the second bend curve section 12 and the end of another first arc section 13, respectively. In other words, the two bend curve sections 12 and the three straight rod sections 11 are connected to form a structure of straight rod section 11—bend curve section 12—straight rod section 11—bend curve section 12—straight rod section 11. This invention designs the main body unit 1 of the stent with a structure consisting of three straight rod sections 11 and two bend curve sections 12, forming an innovative five-segment structure: straight rod section – bend curve section – straight rod section – bend curve section – straight rod section. This achieves a clear inward folding deformation path with the center line as the axis of symmetry. It solves the problem that when biodegradable stents are designed to be thicker and longer in pursuit of support, traditional annular or wavy units are prone to spatial interference during compression, which leads to wrinkles, twisting, or local protrusions of the stent on the balloon. It also further compresses the height of the main body unit of the stent, reduces the stent wall thickness, and significantly improves the radial support force of the stent.

[0036] Furthermore, due to material strength limitations, biodegradable stents typically require thicker walls and wire diameters, and longer main unit lengths, in order to maintain higher radial support. Therefore, traditional annular or wavy units are prone to spatial interference between adjacent units during radial compression. This not only requires greater gripping force but also causes the stent to wrinkle, twist, or protrude locally on the balloon. These geometric defects can easily scratch the vascular intima during implantation, leading to acute thrombosis or hyperplasia. To address the interference problem in current stent gripping techniques, this invention further optimizes the structure of the main unit. A design employing three straight rod sections 11 and two bend curve sections 12 forms a structure of straight rod section—bend curve section—straight rod section—bend curve section—straight rod section, creating a clear inward folding path around the unit's centerline. The five-segment configuration of the three straight rod sections 11 and two bend curve sections 12 effectively constructs a deformable mechanism with kinematic constraints. The two bends 12 resemble flexible hinges, while the three straight sections 11 resemble rigid linkages, together forming a symmetrical folding mechanism with the unit's centerline as the main axis of motion. This design ensures that after the stent is pressed onto the delivery balloon, its outer surface forms a smooth, continuous, and coaxial cylinder without any warping or outward turning of the tip, reducing the risk of snagging on the vessel wall when passing through tortuous blood vessels and improving passability. Simultaneously, the uniform pressing state allows for more consistent stent-balloon adhesion, enabling more symmetrical and precise expansion during inflation and release, reducing the "dog bone" effect and ensuring good vessel wall fit.

[0037] Furthermore, the inner side of the first arc portion 13 forms a first inner arc surface, and the outer side of the first arc portion 13 forms a first outer arc surface. The first inner arc surface and the first outer arc surface are not concentric. The radius of the first inner arc surface or the first outer arc surface of the first arc portion 13 is 0.1-0.5mm, for example, it can be 0.2mm, 0.3mm, 0.4mm, etc.; the length of the straight rod portion 11 is 0.1-0.5mm, for example, it can be 0.2mm, 0.3mm, 0.4mm, etc.; if the length of the straight rod portion 11 is less than 0.1mm, it will cause the height of the vascular stent main unit 1 to be too low, and the stent metal coverage rate will exceed the specified standard by 20%; if the length of the straight rod portion 11 is greater than 0.5mm, the height of the stent main unit 1 will be too high, and the radial support force will be reduced.

[0038] Furthermore, the radius of the bend curve portion 12 is 0.1 to 0.5 mm, for example, it can be 0.2 mm, 0.3 mm, 0.4 mm, etc. If the radius of the bend curve portion 12 is less than 0.1 mm, it will cause interference during the pressing process; if the radius of the bend curve portion 12 is greater than 0.5 mm, it will cause the height of the main support unit to be too high and the radial support force to be reduced.

[0039] It should be noted that the first inner arc surface and the first outer arc surface of the first arc portion 13 of the main body unit 1 are not concentric. The distance between the centers of the first inner arc surface and the first outer arc surface is 0.01-0.05mm, for example, 0.02mm, 0.03mm, 0.04mm, etc. If the horizontal distance is less than 0.01mm, the wire diameter thickening at the crests and troughs is not obvious, and the plastic deformation is greater when pressed to the same outer diameter, and it does not play a role in increasing the support force, and interference will occur during pressing. If it is greater than 0.05mm, the wire diameter thickening at the crests and troughs is too large, which makes pressing difficult and the plastic deformation is large, causing cracks and affecting performance.

[0040] This invention designs the first arc portion 13 as a non-concentric arc topology, which uniformly disperses the stress during the compression and expansion of the vascular stent while significantly improving the radial support force of the stent. This achieves synergistic optimization of stent stress distribution and degradation behavior, solving key problems in clinical use of biodegradable alloy vascular stents, such as premature mechanical performance degradation, uneven degradation leading to structural failure, and poor radial support force. The geometric configuration of this structure is based on a slight horizontal offset between the two centers, forming a continuous smooth curve derived from a single geometric definition. This design makes the curvature change continuously differentiable, thereby guiding the stent wire width to present a continuous and natural gradient transition along the contour. Compared to traditional designs with uniform width or simple thickening, this significantly improves the load-bearing efficiency of the structure without significantly increasing the local volume. For biodegradable metals, uniform stress distribution means a more uniform strain field. Material degradation is very sensitive to local stress. Stress concentration points can lead to accelerated local degradation, resulting in pitting or early fracture. The design in this invention eliminates stress concentration, achieving synchronous and uniform overall degradation, which cannot be achieved by simply changing the wall thickness or material. Meanwhile, in finite element modeling, the smooth, continuous geometry of non-concentric circular arcs significantly improves mesh generation quality, avoids mesh distortion at sharp corners, and makes stress calculation results more reliable. Optimal design parameters are obtained through finite element simulation optimization. Furthermore, smooth, continuous surfaces generate less disturbance in the blood flow field, reducing the risk of thrombosis and promoting endothelialization.

[0041] Specifically, the connecting rod 2 has an S-shaped structure, including a long straight portion 22, two short straight portions 24, two arc-shaped portions 21, and two second arc-shaped portions 23. The two ends of the long straight portion 22 are respectively connected to one end of each of the two arc-shaped portions 21, and the other ends of each of the two arc-shaped portions 21 are respectively connected to one end of one short straight portion 24 and one end of the other short straight portion 24. The inner surface of the second arc-shaped portion 23 forms a second inner arc surface, and the outer surface of the second arc-shaped portion 23 forms a second outer arc surface. The second inner arc surface and the second outer arc surface are preferably concentric arc surfaces. The arc-shaped portions 21 are standard concentric semicircles, and the opening directions of the two arc-shaped portions 21 are arranged opposite to each other. Both sides of part 21 are smooth curves. The connecting rod 2 is connected to the main structure support ring 3 through the second arc part 23. That is, the other ends of the two short straight parts 24 are connected to the main structure support ring 3 through the second arc part 23. The connection between the main structure support ring 3 and the second arc part 23 is chamfered. The connecting rod 2 and the main body of the bracket are uniformly connected by the arc chamfer. The arc chamfer range is 0.01-0.04mm, for example, it can be 0.02mm, 0.03mm, etc. If the arc chamfer is less than 0.01mm, it will not have the effect of chamfering. If the arc chamfer is greater than 0.04mm, it will affect the structure of the connecting rod. That is, a chamfer part 25 is formed between the main structure support ring 3 and the second arc part 23. After passing through two concentric second arc parts 23, the connecting rod 2 is uniformly transitioned to the main structure support ring 3 through the chamfer part 25, and smoothly connected.

[0042] It should be noted that the length of the short straight portion 24 is 0.1-0.25 mm, for example, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, etc., and the length of the long straight portion 22 is 0.3-0.6 mm, for example, 0.4 mm, 0.5 mm, etc. If it is less than the above range, the connecting rod 2 structure cannot be formed; if it is greater than the above range, the connecting rod 2 will warp during compression, damaging the inner wall of the blood vessel.

[0043] This invention employs an "S"-shaped connecting rod 2 with a dual-wave buffer structure to eliminate stress concentration points and effectively dissipate deformation energy, solving key reliability problems in biodegradable stents such as accelerated corrosion, premature fracture, and stent disintegration caused by stress concentration in the connecting rod 2. In biodegradable stents, the connecting rod 2 is one of the weakest links. Any stress concentration will lead to an abnormally accelerated corrosion rate at that point, potentially causing premature fracture of the connecting rod 2 before other parts have fulfilled their supporting function, resulting in stent disintegration and the risk of vascular occlusion. For biodegradable stents, traditional connecting rods suffer from severe deformation during compression expansion, stress concentration, and warping, leading to uneven corrosion, premature degradation, and fracture. The "S"-shaped connecting rod 2 is designed with two arc-shaped portions 21 and three straight portions at both ends of the arc-shaped portions 21. Both sides of the arc-shaped portions 22 are smooth curves, and the connecting rod 2 is uniformly connected to the main body of the stent via a circular arc. Our "S"-shaped design is a carefully tuned "flexible joint." Two opposing arc-shaped sections 21 form a double-wave buffer structure, capable of absorbing and dissipating relative displacement and deformation energy from adjacent main units through their smooth deformation with a large radius of curvature. Three straight sections serve as stable anchoring segments, ensuring the connection point between the connecting rod 2 and the main unit 1 is in a low-strain zone. All connections in this design feature smooth curve transitions without any sharp corners or small curvature inflections. This reduces blood flow disturbance in fluid dynamics and completely eliminates stress singularities in solid mechanics, allowing for synchronous and coordinated degradation with the main unit 1, maintaining the integrity of the overall stent structure until the mission is completed. Simultaneously, finite element simulation calculations yielded the optimal dimensions for the connecting rod 2. At this size, while ensuring support, the dimensions of the connecting rod 2 are minimized to avoid warping during clamping and to reduce metal coverage. This achieves uniform stress distribution and avoids uneven corrosion.

[0044] The connecting rods 2 of the vascular stent are arranged in a spiral pattern in space, and the number is preferably 2-4. The outer diameter of the vascular stent is 1-5 mm, for example, 2 mm, 3 mm, 4 mm, etc., and the wall thickness is 0.05-0.3 mm, for example, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.2 mm. The metal rods of the main unit 1 are 1mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, etc., with lengths ranging from 10 to 100mm, such as 20 to 90mm, 30 to 80mm, 40 to 70mm, 50 to 60mm, etc.; the width of the metal rods of the main unit 1 is 0.1 to 0.3mm, such as 0.2mm, etc. The width of connecting rod 2 is 0.06-0.25mm, for example, it can be 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, etc. If the width of connecting rod 2 is less than 0.06mm, connecting rod 2 will degrade too quickly and will be difficult to use for connection. If the width of connecting rod 2 is greater than 0.25mm, interference will occur during gripping. The radius of the approximate semicircle of the centerline of the arc-shaped portion 21 of the connecting rod 2 is 0.03-0.3 mm, for example, it can be 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, or 0.16 mm. The radius of the approximately semicircular centerline of the arc-shaped portion 21 of the connecting rod 2 is outside this range, for example, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm, 0.25 mm, 0.26 mm, 0.27 mm, 0.28 mm, and 0.29 mm. If the radius of the semicircle is outside this range, the connecting rod structure cannot be formed. The biodegradable metal vascular stent allows adjustment of the number of main body units 1 and connecting rods 2 according to the target expansion size without requiring extensive adjustments to the specific outline of the main body unit 1. It can adapt to a wide range of sizes and has excellent flexibility. Based on a defined size range, this invention uses finite element simulation to screen within the specified size parameter range to obtain the optimal vascular stent design parameters.

[0045] The biodegradable scaffold of this invention is made of zinc alloy or magnesium alloy, preferably Zn-Cu-Mn alloy. The weight percentage composition of the Zn-Cu-Mn alloy is: Cu 1.8-2.2%, Mn 0-1.0%, with the balance being Zn. However, it is not limited to this zinc alloy material. For other biodegradable magnesium alloys and zinc alloys, since the elastic modulus, Poisson's ratio, density, and other parameters do not change much, the dimensions of the straight rod portion 11, the bend curve portion 12, and the first arc portion 13 of the main body unit 1 can be slightly adjusted based on the yield strength, elongation, static tensile curve, and expected compression and expansion dimensions, without changing the shape of the main body unit 1.

[0046] In this invention, the biodegradable metallic vascular stent features a multi-body structure support ring 3 that is sequentially connected and surrounds to form a tubular structure. Each support ring 3 includes multiple main body units 1, and adjacent support rings of two main body units 1 are connected by multiple S-shaped connecting rods 2. The two arcs of the crest and trough of the main body unit 1 have a concentric characteristic. This characteristic causes the wire diameter of the stent body to increase uniformly and linearly from both ends of the straight rod 11 towards both ends of the crest and trough, reaching its maximum at the crest and trough apex. Based on the innovative design of the S-shaped connecting rods 2 and the wave-shaped main body units 1 with specific shapes, the vascular stent of this invention not only has better support, flexibility, and fatigue strength, but its design also effectively solves the stress concentration problem of vascular stents during compression and expansion, and can be used for the treatment of peripheral vascular and coronary artery stenosis.

[0047] This invention also provides an application of a biodegradable metal vascular stent in the preparation of medical devices for supporting human cavities. Specifically, the biodegradable metal stent of this invention can be used in the support of multiple human cavities, such as vascular stents, esophageal stents, tracheal stents, bile duct stents, pancreatic duct stents, or urinary catheter stents.

[0048] This invention incorporates a bend curve 12 in the middle of the straight rod of the main body unit 1. This design avoids interference during the gripping process, and the widening of the main body unit 1 further disperses residual stress, resulting in more uniform plastic deformation and improved radial support. The top of the stent, being a stress-concentrated area, features a non-concentric first arc portion 13. This design not only concentrates plastic deformation during gripping and expansion but also enhances the radial support. The "S"-shaped connecting rod 2 allows for better alignment with the balloon after gripping, facilitating delivery to the lesion site and preventing warping during transport. The chamfered design at the connection between the connecting rod and the main body unit 1 ensures a smoother connection. The vascular stent is fabricated using biodegradable zinc alloy. The arc portion of the main body unit 1 employs the same design; compared to the "U"-shaped design, the maximum principal strain decreases by approximately 3.63% with the "S"-shaped design.

[0049] To address the issue of uneven degradation and fracture caused by stress concentration in biodegradable alloy stents due to gradual corrosion and degradation after implantation, this invention presents a high radial support force stent. The three innovative aspects of this invention constitute a comprehensive and interconnected solution: The first point is the non-concentric design of the two first arc sections 13, which optimizes the geometric configuration and stress of the main unit. The second point is the compact configuration of the main unit, which optimizes the overall gripping motion and geometric stability of the stent. The third point is the S-shaped connecting rod 2 design, which optimizes the force transmission path between the main units and the consistency of long-term degradation. These three factors work together to solve the core challenges of biodegradable alloy vascular stents in terms of radial support force, delivery safety, structural reliability, and controllable degradation at different scales.

[0050] Example 1: In this embodiment, the support material is a Zn-Cu-Mn zinc alloy, with Cu accounting for 2%, Mn accounting for 0.5%, and the remainder being Zn. The straight rod 11 has a length of 0.132 mm, the bend curve 12 has a radius of 0.25 mm, the horizontal distance between the two centers of the first arc 13 is 0.0285 mm, and the radius of the first arc 13 is 0.30764 mm. The connecting rod 2 has a width of 0.08 mm, the radius of the approximate semicircle of the center line of the second arc 23 is 0.07436 mm, the short straight section 24 has a length of 0.13 mm, the long straight section 22 has a length of 0.41 mm, the chamfer is 0.03 mm, and the connecting rod 2 has a width of 0.08 mm. In this embodiment, the number of circumferential main body units 1 of the vascular stent is selected as 12. The circumferential connecting rods 2 of the vascular stent are arranged in a spiral shape in space, and in this embodiment, there are 3 of them. The outer diameter of the vascular stent is 3 mm, the wall thickness is 0.1 mm, and the length is 17.62 mm. The width of the metal rod of the main body unit 1 is 0.1 mm, and it transitions evenly to 0.125 mm at the crest and trough. Under these dimensions, the stent performance is as follows: The stent exhibits a radial support force of 197 kPa, an equivalent plastic deformation of 0.2475 kPa, a radial rebound rate of 1.88%, and an axial shortening rate of 0.92%. The low-stress region (less than 200 MPa) accounts for 95.28% of the stent's stress, while the high-stress region (greater than 240 MPa) accounts for 0.31%. The low-stress region (less than 0.5 MPa) between the stent and the blood vessel accounts for 91.35%, and the average stress of the stent on the blood vessel is 0.175 MPa. This embodiment demonstrates high radial support force, low plastic deformation, and excellent mechanical properties.

[0051] Example 2: The difference between this embodiment and Embodiment 1 is that the horizontal distance between the centers of the two non-concentric first arc portions 13 is 0.01 mm, the radius of the first arc portion 13 is 0.1 mm, the length of the straight rod portion 11 is 0.1 mm, and the radius of the arc of the bend curve portion 12 is 0.1 mm. All other material and dimensional parameters are the same as in Embodiment 1. Under these dimensions, the performance of the support is as follows: the radial support force is 230 kPa, and the equivalent plastic deformation is 0.2923. This embodiment exhibits high radial support force, large plastic deformation, and good mechanical properties.

[0052] Example 3: The difference between this embodiment and Embodiment 1 is that the horizontal distance between the centers of the two non-concentric first arc portions 13 is 0.05 mm, the radius of the two non-concentric first arc portions 13 is 0.5 mm, the length of the straight rod portion 11 is 0.5 mm, and the radius of the arc of the bend curve portion 12 is 0.5 mm. All other material and dimensional parameters are the same as in Embodiment 1. Under these dimensions, the performance of the support is as follows: the radial support force is 115 kPa, and the equivalent plastic deformation is 0.2673. This embodiment exhibits good mechanical properties.

[0053] Example 4: The difference between this embodiment and Embodiment 1 is that the connecting rod 2 has a width of 0.06 mm, the radius of the approximate semicircle of the centerline of the arc-shaped portion 21 is 0.03 mm, the length of the short straight portion 24 is 0.1 mm, the length of the long straight portion 22 is 0.3 mm, and the chamfer range is 0.01 mm. All other material and dimensional parameters are the same as in Embodiment 1. Under these dimensions, the performance of the support is as follows: the radial support force is 171 kPa, and the equivalent plastic deformation is 0.2632. This embodiment exhibits high radial support force, large plastic deformation, and good mechanical properties.

[0054] Example 5: In this embodiment, the connecting rod 2 has a width of 0.25 mm, the radius of the approximate semicircle of the centerline of the arc-shaped portion 21 is 0.3 mm, the length of the short straight portion 24 is 0.25 mm, the length of the long straight portion 22 is 0.6 mm, and the chamfer range is 0.04 mm. All other material and dimensional parameters are the same as in Embodiment 1. Under these dimensions, the performance of the bracket is as follows: the radial support force is 182 kPa, and the equivalent plastic deformation is 0.3233. This embodiment exhibits a high radial support force, large plastic deformation, and good mechanical properties.

[0055] Example 6: In this embodiment, the wall thickness of the support is 0.08 mm, and the width of the metal rod of the main unit 1 is 0.1 mm. All other material and dimensional parameters are the same as in Embodiment 1. Under these dimensions, the support's performance is as follows: the radial support force is 120 kPa, and the equivalent plastic deformation is 0.2086. This embodiment exhibits small plastic deformation and excellent mechanical properties.

[0056] Example 7: In this embodiment, the support material is Mg-Nd-Zn-Zr, with Nd accounting for 1%, Zn for 1%, Zr for 1%, and the remainder being Mg. All other dimensional parameters are the same as in Example 1. Under these dimensions, the support performance is as follows: radial support force is 136 kPa, and equivalent plastic deformation is 0.2569. This embodiment exhibits high radial support force, small plastic deformation, and excellent mechanical properties.

[0057] Example 8: In this embodiment, the support material is Zn–Cu–Li, with Cu accounting for 1%, Li accounting for 1%, and the remainder being Zn. All other dimensional parameters are the same as in Example 1. Under these dimensions, the support performance is as follows: radial support force is 210 kPa, and equivalent plastic deformation is 0.2583. This embodiment exhibits high radial support force, small plastic deformation, and excellent mechanical properties.

[0058] Example 9: In this embodiment, the support material is Mg–Zn–Y–Nd, with Zn accounting for 2%, Y accounting for 0.46%, Nd accounting for 0.5%, and the remainder being Mg. All other dimensional parameters are the same as in Example 1. Under these dimensions, the support performance is as follows: the radial support force is 112 kPa, and the equivalent plastic deformation is 0.2368. This embodiment exhibits high radial support force, small plastic deformation, and excellent mechanical properties.

[0059] Comparative Example 1: In Comparative Example 1, the distance between the center of the first inner arc surface and the center of the first outer arc surface on the first arc portion 13 is 0.005 mm, and the remaining material and dimensional parameters are the same as in Example 1. Under these dimensions, the performance of the bracket is as follows: the radial support force of the bracket is 98 kPa, and the equivalent plastic deformation is 0.2932. It can be seen that when the horizontal distance between the two centers of the non-concentric arc portion exceeds the range of 0.01-0.05 mm but is less than 0.01 mm, the support force is significantly reduced (197 kPa in Example 1, 98 kPa in this comparative example), and the plastic deformation increases (0.2475 in Example 1, 0.2932 in this comparative example). When pressed to the same outer diameter, the plastic deformation is even greater, and it does not play a role in increasing the support force.

[0060] Comparative Example 2: In Comparative Example 2, the distance between the center of the first inner arc surface and the center of the first outer arc surface on the first arc portion 13 is 0.06 mm, and the remaining material and dimensional parameters are the same as in Example 1. Under these dimensions, the performance of the support is as follows: the radial support force is 182 kPa, and the equivalent plastic deformation is 0.4688. It can be seen that when the horizontal distance between the two centers of the non-concentric arc portion exceeds the range of 0.01-0.05 mm, and is greater than 0.05 mm, the support force decreases slightly (197 kPa in Example 1, 182 kPa in this comparative example), and the plastic deformation increases (0.2475 in Example 1, 0.4688 in this comparative example). The excessive thickening of the wire diameter at the crests and troughs makes it difficult to grip during pressing, and the plastic deformation is large.

[0061] Comparative Example 3: In Comparative Example 3, the length of the straight rod 11 is 0.05 mm, and the remaining material and dimensional parameters are the same as in Example 1. Under these dimensions, the support performance is as follows: the radial support force is 171 kPa, and the equivalent plastic deformation is 0.2846. It can be seen that when the distance between the straight rods exceeds the range of 0.1-0.5 mm but is less than 0.1 mm, the support force decreases slightly (197 kPa in Example 1, 171 kPa in this comparative example), and the plastic deformation increases (0.2475 in Example 1, 0.2846 in this comparative example).

[0062] Comparative Example 4: In Comparative Example 4, the length of the straight rod 11 is 0.6 mm, and all other material and dimensional parameters are the same as in Example 1. Under these dimensions, the performance of the support is as follows: the radial support force is 93 kPa, and the equivalent plastic deformation is 0.2374. It can be seen that when the distance between the straight rods exceeds the range of 0.1-0.5 mm, and is greater than 0.5 mm, the support force decreases significantly (197 kPa in Example 1, 93 kPa in this comparative example), and the plastic deformation decreases (0.2475 in Example 1, 0.2374 in this comparative example). This is because when the distance between the straight rods is greater than 0.5 mm, the height of the main support unit is too high, the radial support force decreases, and the plastic deformation decreases accordingly.

[0063] Comparative Example 5: In Comparative Example 5, the radius of the arc of the bend curve 12 is 0.05 mm, and all other material and dimensional parameters are the same as in Example 1. Under these dimensions, the performance of the support is as follows: the radial support force is 100 kPa, and the equivalent plastic deformation is 0.4414. It can be seen that when the radius of the arc of the bend curve exceeds the range of 0.1-0.5 mm but is less than 0.1 mm, the support force decreases significantly (197 kPa in Example 1, 100 kPa in this comparative example), and the plastic deformation is large (0.2475 in Example 1, 0.4414 in this comparative example), causing interference during clamping.

[0064] Comparative Example 6: In Comparative Example 6, the radius of the arc of the bend curve 12 is 0.6 mm, and the remaining material and dimensional parameters are the same as in Example 1. Under these dimensions, the performance of the support is as follows: the radial support force is 115 kPa, and the equivalent plastic deformation is 0.3073. It can be seen that when the radius of the arc of the bend curve exceeds the range of 0.1-0.5 mm, and is greater than 0.5 mm, the height of the main support unit is too high, the support force decreases significantly (197 kPa in Example 1, 115 kPa in this comparative example), and the plastic deformation is large (0.2475 in Example 1, 0.3073 in this comparative example), causing interference during clamping.

[0065] Comparative Example 7: In Comparative Example 7, the material is a Sin stent, the connecting rod 2 is a straight connecting rod, and the height of the main unit is 1.36 cm. Detailed parameters can be found in the literature (Chen Chenxin. Structural Optimization Design and Experimental Verification Study of Biodegradable Magnesium Alloy Vascular Stents [D]. Shanghai Jiao Tong University, 2019. DOI:10.27307 / d.cnki.gsjtu.2019.004468). The material parameters are the same as in Example 1. The performance of this comparative example stent is as follows: the radial support force is 92 kPa, the equivalent plastic deformation is 0.2152, the radial rebound rate is 1.84%, and the axial shortening rate is 5.39%. The radial support force is low, the plastic deformation is small, and the mechanical properties are average.

[0066] Comparative Example 8: Comparative Example 8 is made of Mg-Nd-Zn-Zr. The connecting rod 2 is a "U"-shaped connecting rod. The main body unit 1 has a height of 1.40 cm and a wall thickness of 0.12 mm. For detailed parameters, please refer to the literature (Chen Chenxin. Structural optimization design and experimental verification study of biodegradable magnesium alloy vascular stents [D]. Shanghai Jiaotong University, 2019. DOI:10.27307 / d.cnki.gsjtu.2019.004468).

[0067] The performance of the comparative support is as follows: the radial support force is 96.7 kPa, and the equivalent plastic deformation is 0.2347 kPa. The radial support force is low, the plastic deformation is small, the connecting rod warps during compression, and the mechanical properties are generally average.

[0068] Comparative Example 9: Comparative Example 9 has the same structural parameters as Comparative Example 2, and the same material parameters as Example 1. Detailed parameters can be found in the literature (Jiang J, Huang H, Niu J, et al. Fabrication and characterization of biodegradable Zn-Cu-Mn alloy micro-tubes and vascular stents: Microstructure, texture, mechanical properties and corrosion behavior[J]. Acta Biomaterialia, 2022, 151: 647-660). The performance of this comparative example stent is as follows: the radial support force is 150 kPa, and the equivalent plastic deformation is 0.24. It exhibits high radial support force, small plastic deformation, large wall thickness, and generally average mechanical properties.

[0069] Comparative Example 10: Comparative Example 10 is made of Mg–2Zn–0.46Y–0.5Nd, with Zn accounting for 2%, Y for 0.46%, Nd for 0.5%, and the remainder being Mg. The stent has a wall thickness of 0.13 mm, a wire diameter of 0.12 mm, a straight rod length of 0.08 mm, and a distance of 0.04 mm between the centers of the first inner and outer arc surfaces on the first arc portion 13. Detailed parameters can be found in the literature (Li Y, Wang Y, Shen Z, et al. A biodegradable magnesium alloy vascular stent structure: Design, optimization and evaluation[J]. Acta Biomaterialia, 2022, 142: 402-412). The performance of this comparative example stent is as follows: radial support force is 129 kPa, equivalent plastic deformation is 0.249 kPa, radial rebound rate is 2.3%, and axial shortening rate is 4.0%. The radial support force is low, the plastic deformation is small, interference is easy during clamping, and the mechanical properties are generally average.

[0070] Comparative Example 11: Comparative Example 11 is made of Mg–2Zn–0.46Y–0.5Nd, with Zn accounting for 2%, Y for 0.46%, Nd for 0.5%, and the remainder being Mg. The stent has a wall thickness of 0.1 mm, a wire diameter of 0.1481 mm, and a connecting rod width of 0.0803 mm. Detailed parameters can be found in the literature (Wang Y, Yan C, Mei D, et al. Optimized structure design of asymmetrical Mg alloy cerebrovascular stent with high flexibility[J]. Smart Materials in Manufacturing, 2024, 2: 100040). The performance of this comparative example stent is as follows: the radial support force is 80 kPa, and the equivalent plastic deformation is 0.1914. The low radial support force and small plastic deformation mean it cannot provide effective support, and its mechanical properties are generally poor.

[0071] Comparative Example 12: Comparative Example 12 is made of Mg–2Zn–0.46Y–0.5Nd. The stent has a wall thickness of 0.1 mm, a wire diameter of 0.126 mm, and a distance of 0.3 mm between the first inner and outer arc surfaces on the first arc portion 13. Detailed parameters can be found in the literature (Li Y, Wang J, Sheng K, et al. Optimizing structural design on biodegradable magnesium alloy vascular stent for reducing strut thickness and raising radial strength[J]. Materials&Design, 2022, 220: 110843). The performance of this comparative example stent is as follows: radial support force is 89 kPa, equivalent plastic deformation is 0.206 kPa, radial springback is 6.2%, and axial shortening is 2.6%. It exhibits low radial support force, small plastic deformation, and is prone to interference during clamping, resulting in generally poor mechanical properties.

[0072] Comparative Example 13: Comparative Example 13 was made of pure iron. The scaffold had a wall thickness of 0.07 mm; detailed parameters can be found in the literature (Lin W, Qin L, Qi H, et al. Long-term in vivo corrosion behavior, biocompatibility and bioresorption mechanism of a bioresorbable nitrided iron scaffold[J]. Actabiomaterialia, 2017, 54: 454-468). The performance of this comparative example scaffold was as follows: radial support force was 92 kPa, radial rebound rate was 2.24%, and axial shortening rate was 1.01%. The radial support force was low, the degradation rate was too slow, the mechanical properties were average, and the biocompatibility was poor.

[0073] Comparative Example 14: Comparative Example 14 was made of iron nitride. The wall thickness of this scaffold was the same as that of Comparative Example 7; detailed parameters can be found in the literature (Lin W, Qin L, Qi H, et al. Long-term in vivo corrosion behavior, biocompatibility and bioresorption mechanism of a bioresorbable nitrided iron scaffold[J]. Actabiomaterialia, 2017, 54: 454-468). The performance of this comparative example scaffold was as follows: the radial support force was 171 kPa, the radial rebound rate was 2.21%, and the axial shortening rate was 1.22%. It exhibited high radial support force, a slow degradation rate, good mechanical properties, but poor biocompatibility.

[0074] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0075] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A biodegradable metallic vascular stent, characterized by, The main structure support ring (3) comprises a plurality of main body units (1) connected in a wave shape. The plurality of main structure support rings (3) are sequentially connected transversely and then longitudinally wrapped to form a tubular structure, and the adjacent two main structure support rings (3) are connected by a plurality of spacer connecting rods (2), wherein any adjacent two main structure support rings (3) are mutually mirror-symmetric. Each main structure support ring (3) comprises a plurality of main body units (1) connected in a wave shape.

2. The biodegradable metal vascular stent of claim 1, wherein, The main body unit (1) comprises two first circular arc portions (13) and three straight rod portions (11) and two inflection curve portions (12) arranged between the two first circular arc portions (13). The three straight rod portions (11) and the two inflection curve portions (12) are alternately connected.

3. The biodegradable metal vascular stent of claim 2, wherein, One end of the first straight rod portion (11) is connected with the end of one first circular arc portion (13), the other end of the first straight rod portion (11) is connected with one end of the first inflection curve portion (12), both ends of the second straight rod portion (11) are respectively connected with the other end of the first inflection curve portion (12) and one end of the second inflection curve portion (12), and both ends of the third straight rod portion (11) are respectively connected with the other end of the second inflection curve portion (12) and the end of the other first circular arc portion (13).

4. The biodegradable metal vascular stent of claim 2, wherein, The first inner circular arc surface or the first outer circular arc surface of the first circular arc portion (13) has a radius of 0.1-0.5mm. The length of the straight rod portion (11) is 0.1-0.5mm. The inflection curve portion (12) has a circular arc radius of 0.1-0.5mm.

5. The biodegradable metal vascular stent of claim 4, wherein, The first inner circular arc surface and the first outer circular arc surface of the first circular arc portion (13) on each main body unit (1) are not concentric, and the distance between the centers of the first inner circular arc surface and the first outer circular arc surface is 0.01-0.05mm.

6. The biodegradable metal vascular stent of claim 1, wherein, The connecting rod (2) has an S-shaped structure, comprising a long straight portion (22), a short straight portion (24) and an arc-shaped portion (21). Both ends of the long straight portion (22) are respectively connected with one end of two arc-shaped portions (21), and the other ends of the two arc-shaped portions (21) are respectively connected with one end of one short straight portion (24) and one end of another short straight portion (24). The connecting rods (2) in the circumferential direction of the vascular stent are arranged in a spiral shape in space.

7. The biodegradable metal vascular stent of claim 6, wherein, The arc-shaped portion (21) has a U-shaped structure, and the opening directions of the two arc-shaped portions (21) are oppositely arranged. Both sides of the arc-shaped portion (21) are smooth curve-shaped, the connecting rod (2) is connected with the main structure support ring (3) through a second circular arc portion (23), the length of the short straight portion (24) is 0.1-0.25mm, and the length of the long straight portion (22) is 0.3-0.6mm, wherein the connection between the main structure support ring (3) and the second circular arc portion (23) is chamfered.

8. The biodegradable metal vascular stent of claim 1, wherein, The outer diameter of the vascular stent is 1-5mm, the wall thickness is 0.05-0.3mm, and the length is 10-100mm. The width of the metal rod of the main body unit (1) is 0.1-0.3mm, and the width of the connecting rod (2) is 0.06-0.25mm. The biodegradable metal vascular stent can adjust the number of the main body units (1) and the connecting rods (2) according to the target expansion size.

9. The biodegradable metal vascular stent of claim 1, wherein, The material is a zinc alloy or a magnesium alloy.

10. Use of the biodegradable metal vascular stent according to any one of claims 1 to 9 in the preparation of a medical device for supporting a human body cavity.

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