保留瓣下结构的几种机械瓣下游血流动力学多普勒超声研究

了解二尖瓣置换术mitralvalvereplacement,MVR保留瓣下结构对不同类型机械瓣下游血流动力学的影响,为合理选择术式以最大限度减少手术并发症提供科学依据。方法采用彩色多普勒超声结合计算机图像分析技术,对保留瓣下结构的不同类型机械瓣置换术后患者机械瓣下游湍流剪应力turbulentshearstress,TSS等指标进行体内定量研究。结果无论保留全瓣或后瓣,跨瓣血流边界位点TSS在两种不同构型机械瓣组间均存在显著性差异(P<0.05),单叶机械瓣(单叶瓣)TSS较双叶机械瓣(双叶瓣)高。对于单叶瓣,TSS在保留全瓣瓣下结构组(保留全瓣组)、保留后瓣瓣下结构组(保留后瓣组)与未保留瓣下结构组(未保留组)间均存在显著差异(P<0.05)。而对于双叶瓣,保留全瓣组TSS均高于其它2组(P<0.05)。结论保留瓣下结构可改善术后患者心功能,但却在一定程度上增加跨瓣血流扰动性,使下游TSS增大。这种影响以全瓣保留者为著,单叶瓣甚于双叶瓣。对于心功能较差,有必要保留全瓣瓣下结构者,可尽量使用双叶瓣,以减轻对人工心瓣下游血流动力学可能产生的不良影响。

Doppler Echocardiographic Study on Hemodynamics in Downstream of Mechanical Heart Valve Prostheses in Mitral Valve Replacement with Preservation of Subvalvular Apparatus

Objective To study the effective of preservation of subvalvular apparatus during mitral valve replacement (MVR) on hemodynamics in downstream of mechanical valve prosthesis(MVP) for providing the scientific basis in selecting suitable operation approaches in minimizing the risk surgical complications. Methods The color Doppler echocardiography combined with computerized image analysis were adopted to quantitatively study the left ventricular function and turbulent shear stress(TSS) in downstream of different kinds of MVP in vivo after MVR with preservation of subvalvular apparatus. Results For those with preservation of either posterior or total subvalvular apparatus, there was a significant difference between the different patterns of MVP for the magnitude of TSS in the boundary locations of flow(P<0.05). TSS of monoleaflet disc was higher than that of bileaflet disc. As to monoleaflet disc,there was a significant difference for the magnitude of TSS between the groups of preservation of total,posterior subvalvular apparatus and of non-preservation(P<0.05). And as to bileaflet disc,the TSS in the group of preservation of total subvalvular apparatus was higher than that in the other two groups(P<0.05). Conclusion Although the cardiac function could be improved through the operation with preservation of subvalvular apparatus,to some extent the turbulent intensity and TSS of transmitral flow would be enhanced, especially for those patients with preservation of total subvalvular apparatus and with monoleaflet. It is considered that for patients with poor cardiac function should be operated with preservation of total subvalvular apparatus, the bileaflet discs should be adopted as possible,then the possible adverse effect on hemodynamics in downstream of MVP will be relieved.