Material and Method: CCTA was performed in 54 symptomatic post-CABG patients. Two independent, blinded observers assessed all grafts and native coronary arteries for significant stenosis. CCA served as a reference standard. One hundred seventy two graft segments, 156 distal coronary run-offs, 314 grafted coronary segments, and 18 non-grafted coronary segments were analyzed.

Results: The diagnostic accuracy of CCTA for exclusion or detection of significant stenosis in venous grafts and non-grafted segments of native coronary arteries was 100%. Sensitivity, specificity, and positive and negative predictive values were all 100%. Sensitivity, specificity, and positive and negative predictive values to detect significant stenosis were 100%, 98%, 91%, and 100%, respectively, in arterial grafts, 100%, 99%,75%, and 100%, respectively, in distal runoffs, and 100%, 87%, 99%, and 100%, respectively, in grafted segments of native coronary arteries.

Conclusion: Non-invasive coronary CT angiography provides high diagnostic accuracy for evaluation of both bypass grafts and native coronary arteries, although, CCTA is more effective in evaluation of bypass grafts as compared to heavily calcified native coronary arteries.

Keywords: Coronary artery bypass surgery, Computed tomography (CT), Coronary angiography, Coronary artery disease