心肌二维跨壁纵向应变诊断冠状动脉狭窄程度

Two-dimensional transmural longitudinal strain in evaluation on severity of coronary artery stenosis

目的探讨采用二维斑点追踪成像(STI)技术检测心肌跨壁纵向应变诊断冠状动脉狭窄程度的价值。方法对31例可疑冠心病患者行超声心动图检查和CT冠状动脉造影(CTCA),根据CTCA结果将心肌节段分为正常心肌组、轻度狭窄心肌组、中度狭窄心肌组、重度狭窄心肌组,测量心内膜下心肌纵向应变(LS-endo)、心外膜下心肌纵向应变(LSepi)及整体心肌纵向应变(LS-global),计算跨壁纵向应变(LS-mural);比较4组心肌间各纵向应变参数差异。结果正常心肌组和轻度狭窄心肌组各应变参数差异无统计学意义(P均>0.05),均大于中度狭窄心肌组及重度狭窄组(P均<0.001);重度狭窄心肌组LS-endo、LS-epi及LS-global小于中度狭窄心肌组(P均<0.001)。以-2.42%为界值,LS-mural诊断中度冠状动脉狭窄的敏感度及特异度分别为51.6%和56.5%[曲线下面积(AUC)=0.56,P<0.001);以-17.22%为界值,LS-endo诊断重度冠状动脉狭窄的敏感度及特异度分别为81.7%和85.4%(AUC=0.89,P<0.001)。结论 LS-mural及LS-endo可准确诊断冠状动脉狭窄程度,为早期诊断冠心病提供了新方法。

Objective To explore the value of transmural longitudinal strain measured with two-dimensional speckle tracking imaging （STI） in evaluation on the severity of coronary artery stenosis. Methods Thirty-one patients with suspected coronary heart disease （CHD） underwent STI and CT coronary angiography （CTCA）. According to the results of CTCA, the myocardial segments were divided into normal group, mild stenosis group, moderate stenosis group and severe stenosis group. The subendocardial longitudinal strain （LS-endo）, subepicardial longitudinal strain （LS-epi） and global longitudinal strain （LS-global） were measured, and the transmural longitudinal strain （LS-mural） was calculated. The above parameters were compared among 4 groups. Results All the LS parameters of normal group and mild stenosis group had no differences （all P〉0.05）, which were all higher than those of moderate stenosis and severe stenosis group （all P〈0.001）. LS-endo, LS-epi and LS-global of severe stenosis group significantly reduced compared with those of moderate stenosis group （all P〈0.001）. The sensitivity and specificity of LS-mural for diagnosing moderate stenosis of coronary artery was 51.6% and 56.5% with cut-off value of -2.42% （area under ROC curve =0.56, P〈0.001）. The sensitivity and specificity of LS-endo for diagnosing severe stenosis of coronary artery was 81.7% and 85.4% with cut-off value of -17.22% （AUC=0.89, P〈0.001）. Conclusion LS-mural and LS-endo can accurately evaluate the severity of coronary artery stenosis, providing an important method in early diagnosis of CHD.