Comparison of Diagnostic Accuracy between Coronary CT Angiography and Conventional Coronary Angiography

Coronary computed tomography angiography (CCTA) is a noninvasive imaging method with a high diagnostic value and minimal complications for evaluating coronary arteries. Therefore, in cases with low and moderate probabilities of coronary artery disease, CCTA can be a good alternative to conventional coronary angiography (CCA). Previous studies with 64- slice CTA have tried to determine its diagnostic accuracy compared with CCA as the gold standard. In this survey, we compared the results of 256-slice CCTA with CTA.
The present cross-sectional descriptive study evaluated 53 patients (36 men) undergoing CCTA and then CCA (except for 4 patients with pervious CCAs). Our primary goal was to compare the 2 imaging methods for the evaluation of coronary lesions and their runoff.
In the coronary artery bypass graft group, the diagnostic accuracy of CCTA for the arterial graft lesions (left internal mammary artery to left anterior descending) had 72.73% sensitivity, 100% specificity, 100% positive predictive value, and 84.2% negative predictive value and its diagnostic accuracy for the venous graft lesions had 100% sensitivity, 80% to 100% specificity, 80% to 100% positive predictive value, and 66.4% to 100% negative predictive value. Apropos runoff (adequacy of perfusion), CCTA had 100% sensitivity, 63.64% specificity, 80% positive predictive value, and 100% negative predictive value in the arterial grafts and 54% to 100% sensitivity and 100% specificity in the venous grafts. In the percutaneous coronary intervention group, CCTA had 90% specificity, and 75% positive predictive value, and 0% negative predictive value in the differentiation of significant nonsignificant in-stent restenoses.
The diagnostic accuracy of CCTA in determining the severity of arterial graft stenoses and their runoff was similar to that reported in previous studies with 64-slice CTA. Strikingly, CCTA had low sensitivity for significant in-stent restenosis. (Iranian Heart Journal 2018; 19(1):30-36)