保留相同瓣下结构比较不同人工瓣膜下游湍流剪应力的差异

Comparison of turbulent shear stress in downstream of different prosthetic valves with preservation of the same subvalvular apparatus

背景:保留瓣下结构可引起瓣膜下游血流受阻,目前有关保留瓣下结构不同人工瓣膜下游血流受阻情况的定量研究尚不深入。目的:比较保留相同瓣下结构、不同类型人工瓣膜下游血流动力学性能的优劣。方法:按常规二尖瓣置换方法,在全麻气管插管体外循环下建立标准的猪二尖瓣置换模型。按未保留瓣下结构、保留后瓣瓣下结构以及保留全瓣瓣下结构3种术式处理猪的二尖瓣及其瓣下结构,置换的瓣膜类型为单叶机械瓣膜、双叶机械瓣膜和生物瓣膜。采用多普勒超声结合计算机图像分析技术,对猪保留相同瓣下结构的不同类型的人工瓣膜下游湍流剪应力进行体内定量实验。结果与结论:未保留瓣下结构的单叶双叶机械人工瓣膜下游血流动力学性能相当,均较生物瓣膜差。保留相同瓣下结构的不同类型人工瓣膜置换后其下游的血流动力学性能以生物瓣膜最佳,双叶机械瓣膜次之,单叶瓣膜最差。

BACKGROUND：The preservation of subvalvular apparatus can cause an obstruction to the blood flow in downstream. At present, there are few quantitative studies on the obstruction to the blood flow in downstream of different kinds of prosthetic valves with preservation of subvalvular apparatus. OBJECTIVE：To the compare the advantages and disadvantages of hemodynamic properties in downstream of different kinds of prosthetic valves with preservation of the same subvalvular apparatus. METHODS：According to the common mitral valve replacement, a standard porcine mitral valve replacement model was established under general anesthesia involving cardiopulmonary bypass. The porcine mitral valve and its subvalvular apparatus were performed three kinds of surgeries：without preservation of the subvalvular apparatus, preservation of the posterior subvalvular apparatus and preservation of the entire subvalvular apparatus. And the implanted valves included monoleaflet mechanical valve, bileaflet mechanical valve and bioprosthetic valve. Turbulent shear stress in downstream of different kinds of prosthetic valves with procine preservation of the same subvalvular apparatus was performed in vivo quantitative experiment by color Doppler echocardiography combined with computerized image analysis. RESULTS AND CONCLUSION：Hemodynamic performances in downstream of monoleaflet mechanical and bileaflet mechanical valves without preservation of the subvalvular apparatus were the same, which were worse than that of bioprosthetic valve. Of the three kinds of prosthetic valves, the hemodynamic performance in downstream of the bioprosthetic valve with preservation of the same subvalvular apparatus was the best, the bileaflet mechanical valve was worse, while the monoleaflet mechanical valve was the worst.