Preparation of valved mitral stent and in vitro experimental implantation to mitral position through catheter / 第二军医大学学报

ABSTRACT

Objective: To prepare valved mitral stent and to discuss the feasibility of transcatheter implantation of the valved mitral stent in vitro. Methods: We designed a self-expandable stent made of super-elastic Ni-Ti shape memory alloy. The stent was composed of double disks with tubular linkage between them. A valvular ring made of nitinol wire was sutured on the tubular part. Fresh sheep pericardium was cross-linked with a 0.6% glutaraldehyde solution for 36 hours then sutured into a valvular ring; the latter was sutured onto the nitinol self-expandable stent. Through a sheath across the interatrial septum positioned in the left ventricle of isolated sheep heart via vena cava, the device was delivered into the native mitral valve position. When the left ventricle disk was deployed, it was applied to the mitral annulus by pulling back the external sheath. The waist and the left atrial disk were deployed by pulling the sheath in the annulus and left atrium, respectively. Thus the whole device was deployed in the mitral native. Water was injected into the pulmonary veins and left ventricle to test competence of the prosthetic heart valves. Results: The prepared valved mitral stent could be stably positioned at the native valves. There was no stent migration when it was repeatedly pulled. The two disks sandwiched the native mitral valve with one disk lying in the left ventricle and the other one in the left atrium. The prosthetic heart valves showed satisfactory function without structure damage. Conclusion: This self-expandable stent is well designed and can be safely implanted in the mitral valve position via transcatheter approach, and the function of the stent is satisfactory.