Twinning hearts and minds

In this issue of Neurology , Potter et al.1 report results from an innovative twin study addressing the relationship of coronary artery bypass surgery (CABG) to cognitive function. Despite >40 years of clinical experience, it remains uncertain whether CABG has an impact on basic mental faculties such as problem solving and memory. As new endovascular and surgical techniques offer alternatives to traditional CABG for some patients, the relationship between CABG and cognitive function is likely to be increasingly important to patient decision making. Furthermore, if CABG is associated with adverse cognitive outcomes, physicians will need to consider changes in care that may eliminate or reduce this complication. CABG can result in a variety of neurologic complications, including stroke, delirium, and short-term cognitive dysfunction. Several mechanisms relating these complications to ischemic injury in the brain have been proposed, including hypoxia, hypoperfusion, and emboli resulting from cardiac bypass or aortocardiac manipulation. Studies using diffusion-weighted MRI have demonstrated that new areas of cerebral infarction are relatively common after CABG even in individuals without clinical signs of stroke.2 Given that there is strong epidemiologic evidence relating such silent infarcts to cognitive decline and dementia,3,4⇓ it is plausible that CABG may be associated with adverse cognitive outcomes, particularly in the …