Multislice computed tomography for the evaluation of coronary bypass grafts and native coronary arteries: comparison with traditional angiography.

BACKGROUND: Multislice computed tomography (CT) is a promising new noninvasive technique for the detection of atherosclerotic disease within a vessel's wall. The present study was designed to assess the diagnostic accuracy of 64-slice CT in detecting graft disease and in the evaluation of native vessels distally to the grafts.

METHODS: Forty consecutive patients with previous coronary artery bypass underwent both invasive coronary angiography and 64-slice CT. The CT data were acquired over 7-12 s period during a single-breath hold using the Smartprep technique. Images were reconstructed using the retrospective modality on a synchronized ECG in a time frame of between 40 and 80% of the R-R interval.

RESULTS: A total of 118 grafts were investigated (80 vein and 38 arterial conduits). At CT, 31/38 arterial grafts were classified as patent and free from significant lesions, whereas seven appeared diseased (five complete occlusion and two significant stenoses along the body of the graft). Out of 80 vein grafts, 52 appeared free of disease and 28 diseased (23 total occlusion and five critical stenosis). An absolute concordance between CT and angiographic findings was documented for all arterial and venous grafts (100% diagnostic concordance). The accuracy of 64-slice CT in the assessment of distal run-off arteries was 90%.

CONCLUSION: The 64-slice CT detected with very high accuracy the presence of diseased arterial and vein grafts. Moreover, an optimal diagnostic accuracy was also documented in the appraisal of native vessels distal to the graft anastomoses. On the basis of these results, 64-slice CT can be proposed for the study of patients after coronary artery bypass and may represent an effective screening technique to select those patients with indications of new revascularization.