Cognitive dysfunction after coronary artery bypass graft surgery

Coronary artery bypass graft surgery (CABG) is one of the most commonly performed major surgical procedures. However, patients having undergone CABG may experience neurological problems such as stroke, delirium, and cognitive difficulties. Observations suggest that these complications are caused by several synergistic factors, most prominently brain ischemia secondary to cerebral hypoperfusion and/or embolization of heterogeneous endovascular debris. Embolic signals are commonly detected during surgery using intraoperative transcranial Doppler monitoring. After surgery, magnetic resonance imaging of the brain may detect scattered areas of brain ischemia in patients with or without delirium. The large majority of these patients do not exhibit focal neurological deficits suggestive of ischemic stroke. We review the literature pertaining to postoperative encephalopathy, with emphasis on prevention, diagnosis, and treatment.