Correlation Between Pre-operative Brain Magnetic Resonance Angiography Findings and Intra-operative Cerebral Oxygen Saturation During Coronary Artery Bypass Graft Surgery

Coronary artery bypass graft (CABG) patients often have cerebrovascular disease and pre-operative brain magnetic resonance angiography (MRA) frequently reveals cerebral vasculature stenosis. This study was designed to investigate whether pre-operative MRA findings correlated with regional cerebral oxygen saturation (ScO(2)) in 120 patients undergoing on-pump or off-pump CABG. Following MRA examination, patients were divided into six groups of 20 patients each based on MRA findings (no stenosis, mild stenosis or severe stenosis) and procedure (on-pump or off-pump CABG). Mean ScO(2) values over 3 min were determined at seven periods during surgery. Patients with severe cerebrovascular stenosis showed significantly lower ScO(2) than other groups during off-pump CABG. During on-pump CABG, ScO(2) decreased significantly during cardiopulmonary bypass in all groups and was significantly lower in the severe stenosis group. Pre-operative MRA and intra-operative ScO(2) monitoring may help to identify patients at increased risk of brain damage during or following CABG.