瓣下结构保留方式对二尖瓣置换术后瓣膜下游湍流剪应力的影响

Effect of subvalvular apparatus preservation method on turbulent shear stress in downstream in pigs with mitral valve replacement

目的观察瓣下结构保留方式对二尖瓣置换术后猪瓣膜下游湍流剪应力(TSS)的影响。方法滇南小耳猪27只,在全麻气管插管体外循环下行二尖瓣置换术。随机分为A、B、C组,各9只,分别采用单叶机械瓣膜、双叶机械瓣膜和生物瓣膜行二尖瓣置换。每组又分为3个小组,各3只,A1、B1、C1组未保留瓣下结构,A2、B2、C2组保留后瓣瓣下结构,A3、B3、C3组保留全瓣瓣下结构。采用彩色多普勒技术检测各组人工心瓣下游湍流剪应力。结果猪单叶瓣膜置换术后二尖瓣下游两核心区位点TSS组间比较P均>0.05,边界位点TSS组间比较P均<0.05,保留后瓣瓣下结构者高于不保留瓣下结构者,低于全保留瓣下结构者(P均<0.05)。猪双叶瓣膜置换术后、生物瓣膜置换术后二尖瓣下游两核心区位点TSS组间比较P均>0.05,边界位点TSS不保留瓣下结构者和保留后瓣瓣下结构者相比P>0.05,全保留瓣下结构者高于不保留瓣下结构和保留后瓣瓣下结构者(P均<0.05)。结论采用单叶机械瓣行二尖瓣置换术保留后瓣和保留全瓣均可引起跨瓣血流湍流强度增大,且保留全瓣高于保留后瓣者;采用双叶瓣膜和生物瓣膜者,保留后瓣瓣下结构不会导致跨瓣血流湍流强度增大,但保留全瓣可引起跨瓣血流湍流强度增大。

Objective To observe the effect of subvalvular apparatus preservation method on turbulent shear stress in downstream in pigs with mitral valve replacement（MVR）.Methods The color Doppler echocardiography combined with computerized image analysis were adopted to turbulent shear stress in downstream of the same kinds of prosthetic valve in vivo after MVR with preservation of different kinds of subvalvular apparatus.Results For those with different preservation of subvalvular apparatus,there was no significant difference among different kinds of prosthetic valve for the magnitude of TSS in the core area sites（P0.05）.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（P0.05）,TSS of the preservation of total subvalvular apparatus is higher than that of preservation of posterior subvalvular apparatus,TSS of preservation of posterior subvalvular apparatus is higher than that of preservation of non-subvalvular apparatus.As to Bileaflet disc and Biological 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（P0.05）,TSS of the preservation of total subvalvular apparatus is higher than that of preservation of posterior subvalvular apparatus and that of preservation of non-subvalvular apparatus,there was no significant difference among TSS of preservation of posterior subvalvular apparatus and non-subvalvular apparatus（P〈0.05）.Conclusions As to Monoleaflet disc,the hemodynamic in downstream of preservation of non-subvalvular apparatus is better than that in downstream of posterior subvalvular apparatus,and the hemodynamic in downstream of posterior subvalvular apparatus preservation is better than that in downstream of total subvalvular apparatus preservation.As to Bileaflet disc and Biological disc,the hemodynamic in downstream of non-subvalvular apparatus preservation is the same to that in downstream of preservation of posterior subvalvular apparatus preservation,the hemodynamic in downstream of posterior subvalvular apparatus preservation and non-subvalvular apparatus preservation is better than that in downstream of total subvalvular apparatus preservation.