保留瓣下结构的二尖瓣机械瓣下游湍流强度的体内定量研究

Quantitative Study on Turbulent Intensity Downstream of Mitral Mechanical Heart Valve in Patients Undergoing Mitral Valve Replacement with Preservation of Subvalvular Apparatus

目的 了解保留瓣下结构对机械瓣下游血流动力学的影响 ,为临床上选择合理术式提供科学依据 .方法 采用与计算机图像分析相结合的彩色多普勒技术 ,对一组保留瓣下结构的不同类型机械瓣置换术后病人瓣膜下游相对扰动强度 (Relativeturbulentintensity,Irel)等指标进行检测与分析 .结果 无论保留后瓣或全瓣瓣下结构 ,单叶机械瓣 (单叶瓣 )下游Irel均较双叶机械瓣 (双叶瓣 )高 (p <0 .0 5 ) .对于双叶瓣 ,保留后瓣瓣下结构组 (保留后瓣组 )和未保留瓣下结构组 (未保留组 )之Irel均低于保留全瓣瓣下结构组 (保留全瓣组 ) (p<0 .0 5 ) ;而对于单叶瓣 ,保留后瓣组Irel低于保留全瓣组 (p <0 .0 5 ) ,同时高于未保留组 (p <0 .0 5 ) .结论 保留瓣下结构可引起跨瓣血流湍流强度增大 ,尤见于全瓣瓣下结构均保留者 。

Objective To investigate the effect of preservation of subvalvular apparatus on hemodynamics downstream of mechanical heart valve (MHV) in order to offer the scientific basis for selecting rational surgical procedure. Methods Using color Doppler echocardiography combined with the analysis of image by compute, we measured and analyzed the relative turbulent intensity downstream of the different sorts of MHV in a group of patients undergoing mitral valve replacement with preservation of subvalvular apparatus. Results For both the preservation of posterior subvalvular apparatus and that of total subvalvular apparatus, I rel downstream of the monoleaflet prosthesis was higher than that downstream of the bileaflet one(p<0.05). As to bileaflet valve, I rel of the group with preservation of posterior subvalvular apparatus and of the other one without preservation were lower than that of the group with preservation of total subvavular apparatus(p<0.05). And as to monoleaflet one, I rel of the group with preservation of posterior subvalvular apparatus was lower than that of the one with total preservation(p<0.05),and was higher than that of the another one without preservation(p<0.05). Conclusion Preservation of subvalvular apparatus can lead to the increase of I rel of transmitral flow, especially for those with preservation of total subvalvular apparatus and for those with monoleaflet prosthesis.