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

Abstract

To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT). 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. 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). 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.