We wanted to evaluate the accuracy of using ECG-gated CT angiography (CTA) for the assessment of coronary bypass graft patency.

This study included 48 patients who underwent both CTA and conventional angiography to evaluate coronary bypass graft patency. CTA was performed with a 16-detector row multislice CT scanner. We calculated the sensitivity and specificity of CTA to detect occlusion of bypass graft that was equal to or greater than 50% of the expected diameter. Conventional angiography served as a gold standard. A total 160 grafts were evaluated. The diagnostic accuracy was evaluated according to a variety of factors (heart rate, types of bypass graft, target vessel, and surgical techniques).

The overall sensitivity, specificity and accuracy of CTA were 83.9%, 95.4% and 93.1%, respectively. There was no significant statistical difference for each factor according to Fisher's exact test. Although the grafts anastomosed to the left circumflex arterial branches and a high heart rate showed a statistically significant high risk of misdiagnosis on the simple logistic regression test, a high heart rate was the only significant factor on the multiple logistic regression test (odds, 5.9).

CTA provides for good noninvasive evaluation of the coronary bypass graft patency. The heart rate and the anastomosed vessel are factors that can influence the accuracy.