Multidetector Computed Tomography Versus Coronary Angiogram in Evaluation of Coronary Artery Bypass Grafts

Abstract

The new evolving multidetector computed tomography (MDCT) is thought to be promising in imaging of coronary disease. We compared the evaluating power of MDCT to that of conventional coronary artery angiogram in patients with coronary artery bypass grafting surgery. From April 2002 to December 2003, 50 patients underwent both MDCT and coronary artery angiogram after coronary artery bypass surgery. Overall, 170 grafts were studied. Two weeks after the surgery, 8-row MDCT was taken using contrast medium to observe the grafts patency. Three weeks after the surgery, conventional coronary angiogram was done to verify the graft status. The graft status was classified according to Fitzgibbon classification. Sensitivity, positive predictive value, and negative predictive value were calculated and compared. Multidetector computed tomography succeeded in high-quality imaging of all grafts except for one (less than 1 mm gastroepiploic graft to posterior descending artery). This graft was the only graft that was interpreted differently. Overall patency rate was 97.8%. The diagnostic power of MDCT was as follows: the specificity was 99.4%, the sensitivity was 100%, the positive predictive value was 100%, and the negative predictive power was 80%. In this study, 8-row MDCT showed reliable imaging power in verifying grafts status. Since MDCT is much less invasive for patients, conventional coronary artery angiogram will be substituted by evolving MDCT.