Development of Angioplasty Ring Using Thermal Shape Memory Alloy

为预防血管成形术后再狭窄，开发了一种非手术植入血管成形环的新技术。用热形状记忆合金制作了血管成形环。这种热形状记忆合金由55%的镍和45%的钛组成，具有独特的热形状记忆性能。如果这种合金被约束到所需的形状，并在超过约650ﾟC的温度下进行退火，它将记住该形状。然而，当在冰水中冷却时，金属丝变得软弱无力，可以变形，而不会破坏它的记忆。当这种变形的金属丝被加热到其转变温度时，它很快就会恢复到原来的退火态。所用的血管成形术环形导管直径为7F和4F，带有球囊。血管成形术环被缠绕在导管的末端。在透视下将导管插入动脉。放置好后，通过导管注入热盐水(50ﾟC 10ml)以扩张环。将12枚血管成形环(内径5 mm，长度5 mm，厚度0.25 mm)植入犬的髂总动脉内。治疗1年后10/12环再通，2年后4/4环再通。将10个血管成形环(内径3 mm，长度5 mm，厚度0.15 mm)植入兔腹主动脉。术后1个月有9/10环通畅，表明血管成形术环具有良好的临床应用前景。

A new technique was developed for non-surgical implantation of an Angioplasty Ring to prevent restenosis following angioplasty. An Angioplasty Ring was made by thermal shape memory alloy. This thermal shape memory alloy composed of 55% nickel and 45% titanium by weight with unique thermal shape memory properties. If this alloy is constrained to a desired shape and annealed at temperatures in excess of approximately 650ﾟC, it will memorize that shape. However, when cooled in ice water, the wire become limp and can be deformed without destroying its memory. When this deformed wire is heated to its transition temperature, it rapidly returns to its original annealed shape.An Angioplasty Ring Catheter used was 7F and 4F in diameter with balloon. The Angioplasty Ring was wound on to the tip of the catheter. The Catheter was inserted into the artery under fluoroscopy. once in place, hot salin (50ﾟC 10ml) was injected through the Catheter to expand the ring. Under fluoroscopy, the ring was opened immediately by hot salin and fixed in the artery by its own expandability.12 Angioplasty Rings (ID 5mm, length 5mm, thickness 0.25mm) were implanted in the common iliac artery of dogs. 10/12 rings were patent at 1 year study and 4/4rings were patent at 2 year study. 10 Angioplasty Rings (ID 3mm, length 5mm, thickness 0.15mm) Which will be used for human coronary artery were implanted in the abdominal artery of rabbits. 9/10 rings were patent at 1 month study.These results show Angioplasty Ring is promising for clinical application.