Brain Injury from Cardiac Bypass Procedures

Patients who undergo coronary artery bypass grafting (CABG) are at increased risk for brain injury. Surgical techniques have advanced so that the risk of neurological sequelae is decreased, but there remains significant morbidity and mortality related to the postoperative period as well as to the surgery itself. In addition, patients who undergo CABG have comorbidities or demographic factors that may increase their likelihood of developing neurological complications. Pathophysiological mechanisms of cerebral injury after CABG range from hemodynamic compromise to embolization, either intraoperatively or postoperatively. Biochemical markers such as S100 and neuron-specific enolase may play a role in the prediction of outcome after CABG, and because of this may help elucidate other potential risk factors. Specific neurological sequelae are discussed, such as stroke, with summaries of the apparent risk factors, as well as encephalopathy, seizure, and both short- and long-term cognitive deficits. Changes in surgical technique have led to some improvements, but there is no definitive information yet as to the role of some of these, such as the use of off-pump CABG. Other techniques such as the use of an arterial filter are discussed, as are their potential benefits in the prevention of neurological complications.