左室压力—应变环技术评估左室射血分数保留的慢性主动脉瓣关闭不全患者心肌功能

Evaluation of left ventricular pressure-strain loop in myocardial function in chronic aortic valve regurgitation with preserved left ventricular ejection fraction

目的应用左室压力-应变环技术评估左室射血分数(LVEF)保留的慢性主动脉瓣关闭不全(CAR)患者主动脉瓣置换或修复(AVR)术前术后心肌功能,探讨其临床应用价值。方法选取扬州大学附属苏北人民医院确诊为中重度CAR并行AVR治疗的LVEF保留患者52例(CAR组),以及同期健康成人40例为健康对照组,检测两组左室整体纵向应变(GLS),并应用左室压力-应变环技术获取无创心肌做功参数,包括整体做功指数(GWI)、整体有效功(GCW)、整体无效功(GWW)、整体做功效率(GWE);比较CAR组术前术后GLS及无创心肌做功参数的差异。分析无创心肌做功参数与GLS、LVEF的相关性。根据术后GLS、GWI损伤情况将CAR患者进一步分为术后GLS及GWI均保留患者15例(Ⅰ组)、术后GLS损伤而GWI保留患者23例(Ⅱ组)、术后GLS及GWI均损伤患者14例(Ⅲ组),比较各亚组超声心动图检查结果的差异。绘制受试者工作特征(ROC)曲线分析GWI预测左室重构的诊断效能。评估观察者内和观察者间测量无创心肌做功参数的一致性。结果CAR组术前LVEF、GLS、GWI、GCW、GWW、GWE与健康对照组比较差异均有统计学意义(均P<0.05);CAR组术后GLS、GWI、GCW、GWE均较术前减低,差异均有统计学意义(均P<0.05)。相关性分析显示,GWI、GCW与GLS分别呈高度及中度相关(r=0.71、0.67,均P<0.05),与LVEF呈中度相关(r=0.46、0.43,均P<0.05);GWE与GLS、LVEF分别呈中度及高度相关(r=0.63、0.72,均P<0.05)。术后CAR患者各亚组LVEF、GLS、GWI、GCW、GWW、GWE比较差异均有统计学意义(均P<0.05)。ROC曲线分析显示,取GWI截断值为1280 mm Hg%时,其预测左室重构的曲线下面积为0.9466,灵敏度为89%,特异度为74%。一致性分析显示观察者内和观察者间测量GWI、GCW、GWW、GWE的组内相关系数分别为0.98、0.95、0.94、0.97和0.97、0.92、0.90、0.96,一致性均良好。结论左室压力-应变环技术可有效评估LVEF保留的CAR患者心肌力学和能量学改变,并反映其术后左室逆重构过程,具有较好的临床应用价值。

Objective To evaluate the changes of myocardial function in patients with aortic valve regurgitation(CAR)with preserved left ventricular ejection fraction(LVEF)before and after aortic valve replacement or repair(AVR)by left ventricular pressure-strain loop,and to explore its clinical application value.Methods A total of 52 patients with moderate and severe CAR who underwent AVR were selected from Subei People’s Hospital Affiliated to Yangzhou University,and 40 healthy adults during the same period were selected as control group.Global longitudinal strain(GLS)was measured in both groups,and non-invasive myocardial work parameters were obtained by left ventricular pressure-strain loop,including global work index(GWI),global constructive work(GCW),global wasted work(GWW),and global work efficiency(GWE).The Changes of GLS and non-invasive myocardial work parameters were compared before and after AVR in the CAR group.The correlation between non-invasive myocardial work parameters and GLS,LVEF was analyzed.According to the postoperative GLS and GWI injury,the CAR patients were further divided into three subgroups:patients with preserved GLS and GWI(groupⅠ,15 cases),patients with GLS injury and preserved GWI(groupⅡ,23 cases),and patients with both GLS and GWI injury(groupⅢ,14 cases).The differences of echocardiographic findings among the subgroups were compared.Receiver operating characteristic(ROC)curve was drawn to evaluate the diagnostic performance of GWI in predicting left ventricular remodeling.The consistency of measurements of non-invasive myocardial work parameters intra-and inter-observers were assessed.Results Before AVR,the CAR group showed significant differences in LVEF,GLS,GWI,and GCW,GWW,GWE compared with the control group(all P<0.05).After AVR,GLS,GWI,GCW and GWE were significantly decreased compared with the results before AVR(all P<0.05).Correlation analysis showed that GWI,GCW were highly and moderately correlated with correlated GLS(r=0.71,0.67,both P<0.001),and moderately correlated with LVEF(r=0.46,0.43,both P<0.05).GWE was moderately and highly correlated with GLS and LVEF(r=0.63,0.72,both P<0.05).There were significant differences in LVEF,GLS,GWI,GCW,GWW,GWE among the subgroups(all P<0.05).ROC curve analysis showed that the GWI cutoff value of 1280 mm Hg%had an area under the curve of 0.9466(P<0.01),with a sensitivity of 89%and specificity of 74%for predicting left ventricular remodeling.Consistency analysis showed good intra-observer and inter-observer agreement for GWI,GCW,GWW and GWE(intra-class correlation coefficients were 0.98,0.95,0.94,0.97,and inter-class correlation coefficients were 0.97,0.92,0.90,0.96,respectively).Conclusion Left ventricular pressure-strain loop can effectively evaluate myocardial mechanics and energetics changes in CAR patients with preserved LVEF,and reflect the process of left ventricular reverse remodeling after AVR.It has good clinical application value.