CT血流储备分数对心肌缺血病变的诊断效能

Diagnostic value of CT based fractional flow reserve in evaluating myocardial ischemia

目的以导管测量血流储备分数(FFR)为金标准,评价基于血流动力学优化融合模型的CT血流储备分数(CT-FFR)对冠状动脉狭窄所致心肌缺血病变的诊断效能。方法前瞻性选择127例接受冠状动脉CT血管成像(CCTA)、1周内冠状动脉造影及经导管FFR测量患者(152支血管),以CCTA观察病变狭窄程度,计算CT-FFR。以FFR<0.8为判断心肌缺血金标准,绘制CT-FFR及CCTA的ROC曲线,获得AUC。计算两种方法诊断心肌缺血的敏感度、特异度、阳性预测值、阴性预测值及准确率。结果 CT-FFR与导管测量FFR一致性良好,仅6.6%测量值在95%一致性界限之外。CT-FFR诊断心肌缺血AUC在患者水平(0.92 vs 0.69,P<0.001)和血管水平(0.93 vs 0.69,P<0.001)均优于CCTA。以患者水平CT-FFR<0.8诊断心肌缺血的敏感度、特异度和准确率分别为84.1%、90.6%和85.8%,CCTA>50%分别为82.5%、54.7%和68.5%;血管水平CT-FFR<0.8分别为88.0%、84.7%和84.9%,CCTA>50%分别为80.6%、57.7%和69.1%。CT-FFR对于血管水平狭窄程度30%~70%病变诊断效能仍佳。结论 CT-FFR对心肌缺血病变的诊断效能优于CCTA,有助于临床筛查心肌缺血病变。

Objective To explore the diagnostic value of CT based fractional flow reserve(CT-FFR) for myocardial ischemic disease caused by coronary artery stenosis using hemodynamic optimal fusion model taken fractional flow reserve(FFR) measured with invasive coronary angiography(ICA) as the gold standard. Methods Coronary CT angiography(CCTA) was performed in 127 patients(152 branches of coronary artery) who then underwent ICA and FFR measurement within 1 week. The degree of vessel stenosis was obtained on CCTA images, and software based on fluid mechanics was used to calculate the value of CT-FFR. Taken ICA showing FFR≤0.8 as the gold standard of hemodynamic stenosis, ROC curves of subjects with CT-FFR<0.8 and CCTA were drawn to obtain AUC. The sensitivity, specificity, accuracy, positive predictive value(PPV) and negative predictive value(NPV) of the two methods were calculated. Results CT-FFR and FFR of 127 patients(152 lesions) had good consistency. The AUC of CT-FFR for diagnosing myocardial ischemia was better than that of CCTA at patient level(0.92 vs 0.69, P<0.001) and vascular level(0.93 vs 0.69, P<0.001). The per-patient sensitivity, specificity and accuracy of CT-FFR<0.8 for identifying myocardial ischemia was 84.1%, 90.6% and 85.8%, respectively, while was 82.5%, 54.7% and 68.5%, respectively of CCTA showing >50% stenosis. The per-vessel sensitivity, specificity and accuracy of CT-FFR<0.8 for identifying myocardial ischemia was 88.0%, 84.7% and 84.9%, while was 80.6%, 57.7% and 69.1% respectively of CCTA showing >50% stenosis. For 30%-70% stenosis, CT-FFR still had very good diagnostic efficacy. Conclusion CT-FFR has better diagnostic efficacy of myocardial ischemia than CCTA, therefore being helpful to clinical screening of myocardial ischemic lesions.