Perioperative Covert Stroke in Patients Undergoing Coronary Artery Bypass Graft Surgery

Shown left to right is the incidence of intraoperative cerebral oxygen desaturation events (blue bars), postoperative delirium (red bars) and clinical stroke within 30 days of coronary artery bypass graft (CABG) surgery (green bars) in patients not experiencing (left) or experiencing (right) a perioperative covert stroke. Cerebral oxygen desaturation events (CODEs) occurred when regional cerebral oxygen saturation (ie, oximetry) values declined ≥20% below baseline in either left, right, or both hemispheres during surgery. Cognitive tests were administered before surgery, at hospital discharge, and again 30 days after surgery. Acute infarcts (visible on diffusion-weighted magnetic resonance imaging [DW-MRI] sequences) were present only in the brain (schematic diagrams in grey) of patients who experienced a perioperative covert stroke (black dots within the right brain diagram). Brain diagrams (frontal sections only) are not drawn to scale. Three patients were excluded from the oximetry analysis: 2 patients with incomplete transcripts and 1 patient undergoing off-pump CABG surgery. CI, Confidence interval. ∗Covert stroke was associated with higher rates of cerebral oxygen desaturation events during surgery (12 [67%] patients with covert stroke vs 9 [32%] without covert stroke [P = .02]).