Evaluation of coronary artery bypass graft patency using three-dimensional reconstruction and flow study of electron beam tomography.

OBJECTIVE: To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT).
METHODS: Two hundred and fourteen consecutive patients who underwent coronary artery bypass graft surgery were scanned using both EBT angiography with 3-dimensional reconstruction and EBT flow study with time-density-curve analysis.
RESULTS: There were 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts). Among them, 133 (98.5%) of 135 arterial grafts were patent, and 345 (77.7%) of 444 saphenous-vein grafts were patent. Within 5 years or between 5 and 10 years after operation, arterial graft patency exceeded venous graft patency (P < 0.001). Three-dimensional EBT angiography achieved higher sensitivity, specificity and accuracy (97.7%, 94.1% and 96.7%, respectively) than did EBT flow study (88.4%, 82.4% and 85.2%, respectively) for evaluating occlusion or patency of CABG. The intra-graft flow of patent arterial and venous grafts were 4.9 +/- 2.2 ml.min-1.g-1 and 6.9 +/- 2.8 ml.min-1.g-1, respectively (P < 0.001).
CONCLUSION: The combination of EBT three-dimensional reconstruction and flow study can be more effective in the assessment of CABG anatomy and quantification of patent CABG blood flow.