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CN-121971209-A - Degradable zinc alloy vascular stent

CN121971209ACN 121971209 ACN121971209 ACN 121971209ACN-121971209-A

Abstract

The invention provides a degradable zinc alloy vascular stent which is provided with a tubular net-shaped structure and comprises a plurality of support rings (3) which are arranged along the axial direction and connecting rods (1) which are connected with adjacent support rings (3), wherein each support ring (3) is in a wave shape and consists of a plurality of support rod units which are connected in sequence, each support rod unit comprises a first support rod in the middle and two arc-shaped parts which are respectively connected with two ends of the first support rod, the tops of the arc-shaped parts form wave crests or wave troughs of the support rings (3), the adjacent two support rod units are connected through sharing one arc-shaped part, the rod diameter (42) of the middle position (2) of each first support rod is W1, the rod diameter (41) of each support ring (3) at the wave crests and the wave troughs is W2, the rod diameter (41) of each support ring (3) at the wave crests and the wave troughs is larger than W1, and the rod diameter (32) of each support rod (1) is W3, and W3 is smaller than W1.

Inventors

  • NIU JIALIN
  • WANG ZILONG
  • YUAN GUANGYIN

Assignees

  • 上海交通大学

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. A degradable zinc alloy vascular stent, which is characterized by having a tubular net structure and comprising a plurality of support rings (3) which are arranged along the axial direction and a connecting rod (1) which connects the adjacent support rings (3); The support ring (3) is wavy and consists of a plurality of support rod units which are sequentially connected, each support rod unit comprises a first support rod in the middle and two arc-shaped parts which are respectively connected with two ends of the first support rod, and the tops of the arc-shaped parts form peaks or troughs of the support ring (3); The rod diameter (42) of the middle position (2) of the first supporting rod is W1, and the rod diameter of the first supporting rod gradually increases from the middle position (2) to the arc-shaped parts at the two ends; the rod diameter (41) of the supporting ring (3) at the wave crest and the wave trough is W2, and W2 is larger than W1; the rod diameter (32) of the connecting rod (1) is W3, and W3 is smaller than W1.
  2. 2. The degradable zinc alloy vascular stent according to claim 1, wherein the ratio of W2/W1 ranges from 1.14 to 1.4 and the ratio of W3/W1 ranges from 0.8 to 0.95; And/or the vascular stent is made of Zn-Cu-Mn alloy, and comprises the following components, by mass, 0.4-wt-2.75-wt% of Cu, 0.1-wt% of Mn, 0.8% of Mn and the balance of Zn and unavoidable impurities.
  3. 3. The degradable zinc alloy vascular stent according to claim 1, wherein two ends of the connecting rod (1) are respectively connected to the outer sides of the proximal ends 1/5-1/4 of the corresponding first supporting rods on the adjacent supporting rings (3).
  4. 4. A degradable zinc alloy vascular stent according to claim 3, characterized in that the rod diameter of the supporting ring (3) at the junction of the connecting rod (1) is not more than 0.8-0.9 times W2.
  5. 5. The degradable zinc alloy vascular stent according to claim 1, wherein the vascular stent has an outer diameter of 2.4 mm-3.0 mm and a wall thickness of 80-120 μm, and the supporting ring has a height (43) of H1 and H1 of 0.7 mm-1.6 mm.
  6. 6. The degradable zinc alloy vascular stent of claim 1, wherein the vascular stent matrix has an average grain size of 1.8-5.2 μm.
  7. 7. The degradable zinc alloy vascular stent according to claim 1, wherein the vascular stent is provided with a drug-carrying coating on the surface, the coating matrix is at least one of polylactic acid and PCL, PTMC, PGA or a copolymer thereof, and the drug carried is rapamycin and/or paclitaxel.
  8. 8. A method of making the degradable zinc alloy vascular stent of any one of claims 1 to 7, comprising the steps of: S1, smelting and casting an alloy ingot according to the alloy components; s2, processing the alloy ingot into a micro pipe with preset outer diameter and wall thickness through extrusion and drawing processes; S3, carving a blood tube bracket blank sample from the micro tube by adopting a laser processing technology; S4, annealing the vascular stent blank sample, wherein the annealing temperature is 200-320 ℃ and the annealing time is 30-120 min; and S5, carrying out electrochemical polishing on the annealed vascular stent blank sample to obtain the vascular stent with a smooth surface.
  9. 9. The method according to claim 7, wherein in step S2, the outer diameter of the fine tube is 0.02-0.1 mm larger than the outer diameter of the stent and the wall thickness is 20-40 μm larger than the wall thickness of the stent.
  10. 10. Use of a degradable zinc alloy vascular stent in the preparation of a medical device for vascular stenosis or occlusion lesions.

Description

Degradable zinc alloy vascular stent Technical Field The invention relates to a degradable zinc alloy vascular stent, and belongs to the technical field of medical appliances. Background The degradable vascular stent can provide necessary mechanical support at the initial stage of the implantation of coronary artery, and is gradually completely degraded and absorbed within 1-2 years after the blood vessel is completely reconstructed (about 6 months), so that long-term risks (such as life-long medicine taking, extremely late thrombus and the like) brought by the traditional permanent metal vascular stent are avoided, the blood vessel is restored to natural comfort function, and a better long-term solution is provided for vascular interventional therapy. Zinc alloys are considered ideal degradable vascular stent materials because of their excellent combination of properties. The method has moderate degradation rate (about 20-100 mu m/year), is matched with a vascular repair period, has good mechanical property, has enough strength (yield strength of 200-350 MPa) and plasticity (elongation rate of 15-50%), and has good biological safety, and the degradation product zinc ion is a trace element necessary for a human body. However, degradable zinc alloy vascular stents still face the following key challenges: (1) The zinc alloy has the phenomena of room temperature aging and processing softening. The former results in a decay of its mechanical properties during storage or service, while the latter may cause non-uniform deformation and even fracture when the stent expands. This requires the development of new anti-aging, work-hardened zinc alloy materials. (2) The optimal design of the support structure is to realize uniform expansion, reduce fracture risk and meet the window of 'complete degradation within 24 months and no less than 6 months' support time, and the support wire diameter, the shape of the connecting rod and the overall structure are required to be precisely designed to balance the contradiction between radial support force, flexibility and degradation rate. (3) The cooperative regulation and control of mechanics and corrosion, namely stress concentration of the bracket in expansion and service can cause local accelerated corrosion, and the effective supporting time can be shortened. The stress distribution is optimized by structural optimization (such as proper widening at the stress concentration position) and local degradation is slowed down. The invention patent with the patent number of CN115069957B discloses a medical titanium alloy coronary artery coating stent, which has excellent mechanical property, and the tensile strength of a tube exceeds 900MPa, but the stent is not degradable in a human body because of being titanium-based alloy, and has long-term stent restenosis risk after implantation. The patent number CN115192783B discloses a medical degradable left-handed polylactic acid bracket, which has smooth structure, can avoid the damage of right-angle parts to the vascular wall, has good radial supporting strength in the category of degradable polymer brackets, but has certain defects because the mechanical property of the polymer brackets is weaker, so that larger wall thickness is needed to achieve specific radial supporting strength, and the polymer brackets have poorer radial rebound performance. The patent number CN119280470B discloses a degradable magnesium alloy vascular stent based on a 3D printing technology, the patent focuses on the flexibility of the design of the vascular stent made of the magnesium alloy, vascular stents with different structures can be prepared based on different vascular conditions, however, the strength of the vascular stent made of the magnesium alloy is insufficient, the tensile strength of the vascular stent after 3D printing is less than 250MPa, a certain amount of rare earth elements exist in the patent, and the in vivo degradation behaviors of yttrium and zirconium elements are not completely ascertained, so that a certain biocompatibility risk exists. The invention patent with the publication number of CN111778429 discloses a high-strength zinc alloy vascular stent, the tensile strength of a tube used by the stent is more than 300MPa, the elongation is more than 15%, the material has good tensile performance, but the plasticity is slightly insufficient, in addition, the zinc alloy has the problem that the stent is unevenly opened due to strain softening, and the processing technology and the vascular stent structure still need to be designed in a targeted way, so that the smooth and even opening of the stent is ensured. Disclosure of Invention The invention provides a degradable zinc alloy vascular stent. The method solves the problem of aging of zinc alloy at room temperature on the basis of ensuring good mechanical property by the optimized component design and the combination of preparation process regulation, realizes the work hardening capaci