Objectives: 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 fourteen consecutive patients who underwent CABG surgery were scanned using both EBT angiography with three-dimensional reconstruction and EBT flow study with time-density curve analysis.
Results: There was a total of 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts); 133 (98.5%) of 135 arterial grafts were patent, 345 (77.7%) of 444 saphenous vein grafts were patent. Within 5 years or 5-10 years after surgery, 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 EBT flow study (88.4%, 82.4%, and 85.2%, respectively) for evaluating occlusion or patency of CABGs. The intragraft flow of patent arterial and venous grafts were 4.9+/-2.2 ml/min/g and 6.9+/-2.8 ml/min/g, respectively (p<0.001).
Conclusion: The combination of EBT three-dimensional reconstruction and flow study can be more effectively performed in the assessment of CABG anatomy and quantification of patent CABG flow.