Noninvasive Follow-Up of Coronary Artery Bypass Graft Patency Using Multi-Slice Computed Tomography

Abstract

Purpose: We wanted to evaluate the utility of multi-slice computerized tomography (MSCT) for assessing coronary artery bypass graft patency and/or occlusion. Materials and Methods: For 24 patients, both conventional angiography and CT angiography with 4-MSCT were performed within seven days of one another in order to evaluate the accuracy of MSCT with regard to graft patency and/or occlusion. A follow-up CT angiogram was performed in patients with and without symptoms (n=11, n=34, respectively) with 4- or 16-MSCT. We retrospectively compared the results of MSCT to those of conventional coronary graft angiography. Results: Sixty-five grafts were evaluated for the accuracy of MSCT. Six of those 65 were occluded. The sensitivity, specificity, positive predictive value and negative predictive values of MSCT for the diagnosis of graft occlusion were 100% (6/6), 98% (58/59), 86% (6/7) and 100% (58/58), respectively. Patency could not be determined by angiography in two grafts; however, the grafts proved to be patent on MSCT. On follow-up, new graft occlusions in the asymptomatic patients were detected by MSCT in 8.2% of the previously patent grafts at the two years post-op, and in 15.2% at the three years post-op. Conclusion: MSCT is a practical and accurate noninvasive diagnostic tool for following up coronary artery bypass grafts.