Assessment of Patients After Coronary Artery Bypass Grafting Using 64-Slice Computed Tomography

The aim was to investigate the diagnostic accuracy of 64-slice computed tomography (CT) for the identification of obstructive disease in both bypass grafts and native coronary vessels in symptomatic patients with a history of coronary artery bypass grafting. Eighty-nine symptomatic patients (81 men; mean age 64 ± 8 years) were prospectively studied 8 ± 4.5 years after bypass surgery. A total of 287 grafts (89 arterial grafts, 198 venous grafts) and 1,183 segments in 356 native coronary arteries >1.5 mm in diameter were evaluated using 64-slice computed tomographic angiography for the detection of significant stenosis, defined as ≥50% decrease in diameter of artery. Results were compared with quantitative coronary angiography as the standard of reference. Sensitivity, specificity, and positive and negative predictive values of 64-slice CT for the detection of significant lesions in bypass grafts were 98%, 97%, 96%, and 99%, respectively. Segment-by-segment analysis of native coronary arteries and distal runoff vessels for the detection of significant obstructive disease yielded sensitivity of 93% with specificity of 88%. If analysis was restricted to nongrafted and distal runoff segments, sensitivity and specificity were 89% and 94%, respectively. The diagnostic accuracy of 64-slice CT was significantly lower for the evaluation of severely calcified segments. In conclusion, 64-slice CT was a valuable and noninvasive tool for accurate comprehensive assessment of bypass grafts and native coronary circulation. However, its usefulness was limited in the presence of heavy calcium deposits.