CT血流储备分数诊断冠状动脉不同钙化程度冠心病患者心肌缺血的价值

Value of fractional flow reserve derived from CT to the diagnosis of myocardial ischemia in patients with coronary heart disease in different degrees of calcification

目的 观察冠状动脉不同钙化程度冠心病患者冠状动脉CT血管造影血流储备分数(fractional flow reserve derived from CT, CT-FFR)变化,探讨CT-FFR诊断不同钙化程度冠心病患者心肌缺血的价值。方法 单支血管病变冠心病患者81例,入院后均行冠状动脉CT血管造影,计算冠状动脉钙化积分(coronary artery calcium score, CACS),采用人工智能软件计算病变远端CT-FFR值;CT血管造影后14 d内行冠状动脉造影,测量病变血管直径、狭窄程度、病变长度及冠状动脉血流储备分数(fractional flow reserve, FFR)。根据CACS中位数,将81例患者分为轻度钙化组41例(CACS≤91分)和重度钙化组40例(CACS>91分),比较2组合并高血压、2型糖尿病、高脂血症比率及入院时左室射血分数、左心室舒张末期内径及血肌酐、血清低密度脂蛋白胆固醇水平等临床资料。以FFR/CT-FFR≤0.8为心肌缺血诊断标准,采用Bland-Altman法评估FFR与CT-FFR诊断不同钙化程度冠心病患者心肌缺血的一致性;绘制ROC曲线,评估CT-FFR诊断轻、重度钙化冠心病患者心肌缺血的效能。结果 轻度钙化组年龄[(59.4±5.7)岁]小于重度钙化组[(65.3±5.9)岁](t=7.541,P=0.036),吸烟比率(9.7%)低于重度钙化组(47.5%)(χ^(2)=12.181,P<0.001),合并高血压、2型糖尿病、高脂血症比率及入院时左室射血分数、左心室舒张末期内径、血肌酐、血清低密度脂蛋白胆固醇水平与重度钙化组比较差异均无统计学意义(P>0.05)。轻度钙化组病变血管长度[(17.10±13.20)mm]短于重度钙化组[(21.20±14.80)mm](t=-2.145,P=0.013),病变血管直径、病变血管狭窄程度、FFR、CT-FFR与重度钙化组比较差异均无统计学意义(P>0.05)。FFR与CT-FFR诊断轻、重度钙化冠心病患者心肌缺血的95%一致性界限分别为-0.09~0.12、-0.05~0.13,诊断轻、重度钙化冠心病患者心肌缺血的一致性较好。CT-FFR以0.82为最佳截断值,诊断轻度钙化冠心病患者心肌缺血的AUC为0.902(95%CI:0.768~0.973,P<0.001),灵敏度为100%,特异度为70.83%;以0.74为最佳截断值,诊断重度钙化冠心病患者心肌缺血的AUC为0.802(95%CI:0.646~0.911,P<0.001),灵敏度为68.42%,特异度为80.95%。结论 CT-FFR与FFR诊断轻、重度钙化冠心病患者心肌缺血的一致性较好,对轻度钙化冠心病患者心肌缺血的诊断灵敏度高。

Objective To evaluate the changes of fractional flow reserve derived from CT(CT-FFR) in patients with coronary heart disease(CHD) in different degrees of calcification, and to investigate the value of CT-FFR to the diagnosis of myocardial ischemia. Methods Eighty-one patients with single-vessel CHD received coronary CT angiography after admission, coronary artery calcification score(CACS) was calculated and CT-FFR of target lesion was calculated by artificial intelligence software. Coronary angiography was performed to measure the lesion diameter, stenosis degree, length and FFR. According to the median CACS, 81 patients were divided into 41 patients with CACS ≤91(mild calcification group) and 40 patients with CACS >91(severe calcification group). The clinical data were compared between two groups including the percentages of patients with hypertension, type 2 diabetes mellitus and hyperlipidemia, and left ventricular ejection fraction, left ventricular end-diastolic dimension, serum creatinine and low-density lipoprotein cholesterol on admission. With FFR/CT-FFR ≤0.8 as diagnostic criteria for myocardial ischemia, Bland-Altman method was used to evaluate the consistency of FFR and CT-FFR. ROC curve was drawn to evaluate the efficiency of CT-FFR on the diagnosis of myocardial ischemia in coronary heart disease patients with mild and severe calcification. Results Mild calcification group was younger [(59.4±5.7) years] than severe calcification group [(65.3±5.9) years](t=7.541, P=0.036). The percentage of smokers was lower in mild calcification group(9.7%) than that in severe calcification group(47.5%)(χ^(2)=12.181, P<0.001). There were no significant differences in the percentages of patients with hypertension, type 2 diabetes mellitus and hyperlipidemia, and left ventricular ejection fraction, left ventricular end-diastolic dimension,serum creatinine and low-density lipoprotein cholesterol on admission between two groups(P>0.05).The lesion length was shorter in mild calcification group [(17.1±13.2)mm] than that in severe calcification group[(21.2±14.8)mm](t=-2.145,P=0.013).There were no significant differences in the lesion diameter,stenosis degree,FFR and CT-FFR between two groups(P>0.05).The 95% consistency limits of FFR and CT-FFR were -0.09 to 0.12 and -0.05 to 0.13,respectively,indicating agood consistency for diagnosing myocardial ischemia.When the optimal cut-offvalue of CT-FFR was 0.82,the AUCfor diagnosing myocardial ischemia in patients with mild coronary artery calcification was 0.902(95% CI:0.768-0.973,P<0.001),the sensitivity was 100%,and the specificity was 70.83%.When the optimal cut-off value of CT-FFR was 0.74,the AUCfor diagnosing myocardial ischemia in patients with severe calcification was 0.802(95%CI:0.646-0.911,P<0.001),the sensitivity was 68.42% and the specificity was 80.95%.Conclusion CT-FFR has a good consistency with FFR for diagnosing myocardial ischemia in patients with mild and severe calcification coronary heart disease,and has a high diagnostic sensitivity in patients with mild calcification.