Fixing the heart: must the brain pay the price?

Coronary artery bypass grafting surgery (CABG) has been persuasively shown to prolong life expectancy in a broad spectrum of patients with severe ischemic heart disease.1 Improvements in the procedure during the past 2 decades have allowed operative mortality rates to fall while disease severity, comorbidity rate, and procedural complexity have increased. In one area, however, evidence of improvement is harder to discern. Careful studies from a number of groups have now clearly shown that CABG is associated with an increased probability of both shortand long-term (5-year) cognitive dysfunction and consequent reduced quality of life.2,3 The cause of this postoperative cognitive dysfunction is most likely multifactorial, with risk factors classified into 2 broad categories: those that are patient related and those that are procedure related. Predominant patient-related factors include the increasing age of the typical CABG patient and the underlying predisposition of older adult patients to develop cognitive dysfunction after any major operation. For example, the International Study of Postoperative Cognitive Dysfunction found that 26% of patients older than age 60 years who underwent major abdominal or orthopedic surgery experienced cognitive dysfunction 1 week after surgery.4