Noninvasive Assessment of Off-Pump Coronary Artery Bypass Surgery by 16-Channel Multidetector-Row Computed Tomography

Abstract

Sixteen-channel multidetector-row computed tomography (MDCT), with higher spatial and temporal resolution, enables noninvasive visualization of images with reduced motion artifact and breath-holding time. We compared images of 16-channel MDCT and selective bypass graft angiography among patients who had off-pump coronary artery bypass graft surgery. The study, conducted from April 2003 to March 2004, involved 42 patients who underwent off-pump coronary artery bypass graft surgery. Samples yielded a total of 96 arterial grafts, 5 vein grafts. Sixteen-channel MDCT (LightSpeed Ultra 16; GE Healthcare, Milwaukee, Wisconsin) was performed on each patient using 500-ms or 600-ms rotation time, 0.625-mm slice thickness, and mean scanning time of approximately 24 seconds. If several sequential anastomoses in one graft existed, each was calculated as a separate graft. Selective bypass graft angiography yielded a patency rate of 97% (155 of 160). Multidetector-row computed tomography enabled detection of 143 of 155 patent grafts and all 5 occluded grafts visualized by selective bypass graft angiography (100% sensitivity and 93% specificity for graft occlusion after exclusion of grafts not evaluated by MDCT). In 149 graft anastomoses of 143 patent grafts viewed by MDCT, 2 significant stenoses were detected by both selective bypass graft angiography and MDCT. Twelve distal anastomoses were not evaluated by MDCT because of metallic clip artifacts. Evaluation possible graft anastomoses were 92%. Sensitivity and specificity for significant stenosis after exclusion of graft anastomoses not evaluated by MDCT were 100% and 99%, respectively. High-quality 16-channel MDCT images allowed detection of graft occlusion and significant stenosis of graft anastomosis after off-pump coronary artery bypass graft surgery, demonstrating an alternative tool less invasive than selective bypass graft angiography to assess grafts after surgery.