Evaluation of coronary artery bypass grafts and native coronary arteries using 64-slice multidetector computed tomography

Abstract

Background: The conventional use of 16-slice multidetector computed tomography (MDCT) remains somewhat limited for evaluating stenoses in vein graft distal anastomotic sites and in coronary arteries. We investigated the diagnostic accuracy of 64-slice MDCT for assessment of both grafts and coronary arteries in patients with coronary artery bypass grafts.

Method: The study group included 54 consecutive patients. One patient had to be excluded from the study because of arrhythmia. The remaining 53 patients with coronary artery bypass grafts underwent both 64-slice MDCT angiography and invasive coronary angiography. The MDCTs were analyzed for presence of significant stenosis (>50%) or occlusion in grafts and coronary arteries. The results were compared with those of invasive coronary angiography.

Results: Overall, 138 of 146 (94.5%) grafts including distal anastomoses were evaluable with MDCT. Evaluability of arterial grafts, venous grafts, distal runoff arteries, and nongrafted arteries was 90.3%, 98.6%, 84.0%, and 97.3%, respectively. After censoring nonevaluable grafts or arteries and considering them to be positive, the sensitivity to detect significant stenosis or occlusion in arterial grafts was 100% and specificity was 91.4%. In venous graft, sensitivity was 100% and specificity was 98.1%. In distal runoff arteries, sensitivity to detect significant stenoses was 83.3% and specificity was 80.2%. In nongrafted arteries, sensitivity was 100% and specificity was 87.5%.

Conclusions: Sixty-four-slice MDCT showed improved ability to assess bypass grafts and coronary arteries. However, there were still difficulties in assessment of distal runoff arteries in which relatively low diagnostic accuracy was observed that might limit clinical implementation of MDCT.