带瓣膜主动脉瓣支架的研制及体外经导管植入实验

Preparation of valved aortic stent and in vitro implantation to aortic valve position through catheter

目的:评价一种新的带瓣膜主动脉瓣支架经导管植入的可行性及其对冠脉血流的影响。方法:用超弹性镍钛记忆合金丝编织成圆柱状网状支架,腰部凹陷,并将网孔扩大,下段内置瓣膜环,将新鲜的猪心包经脱细胞处理后给予0.6%戊二醛浸泡36h,缝合在瓣膜环上,制成带瓣膜主动脉瓣支架。支架近端连接丝线,收入鞘管,取离体猪心脏标本,经升主动脉将带瓣膜支架送至左室,直视下送至主动脉瓣位置,释放支架,注水观察瓣膜功能及冠脉水流量。结果:制备的带瓣膜主动脉瓣支架可牢固地置于原主动脉瓣位置,释放后可回收,人工瓣膜启闭功能好,冠脉流量及二尖瓣前叶活动未受影响。结论:带瓣膜主动脉瓣支架设计合理,可经导管释放并回收,瓣膜功能良好,不影响冠脉开口,可用于动物体内植入实验研究。

Objective： To evaluate the feasibility of implanting a new self-expanding valved stent for aortic valve implantation and its influence on coronary blood flow. Methods： We designed a self-expanding valved stent made from superelastic memory nitinol alloy, with a tubular shape and a wide mesh in the cavate middle part. A valvular ring made of nitinol wire was sutured on the lower part. Fresh porcine pericardium was decellularized, treated with 0. 6% glutaraldehyde solution for 36 h, trimmed into leaflets, and sutured by hand into the valvular ring. The valved stent was pulled into a 14-French sheath by a silk and positioned in the left ventricle of isolated pig heart via the ascending aorta, and then deployed over the native aortic valves by pulling back the outer sheath. Water was injected into the ascending aorta by a silicon tube to evaluate the competence of the prosthetic heart valves and its effect on coronary flow. Results： The prepared valved aortic stent could be stably positioned over the native valves and could be removed after deployment. The prosthetic heart valves showed a satisfactory function and had no influence on coronary flow and mitral valve motion. Conclusion： This self-expanding valved stent is welldesigned and allows for aortic valve implantation over the native valves without interfering the coronary flow; it can be evaluated further in vivo.