Examining the Neurologic & Cognitive Effects of CABG

Although the mortality rate associated with CABG has been declining, research suggests that patients who undergo these procedures are increasingly older and sicker. Risk factors for complications after CABG are high, and adverse neurologic outcomes (eg, stroke and cognitive decline) remain a major concern. Efforts to reduce post-CABG-related neurologic events have been hindered by an incomplete understanding of the pathophysiology of these events. One of the justifications for developing off-pump CABG was the hope that rates of embolization, and therefore stroke, would be lower than those experienced with on-pump surgery. However, a number of large prospective ran­domized trials have failed to show a significant difference in rates of post-surgical stroke between on- and off-pump bypass. In light of these findings, strategies to reduce the incidence of adverse post-CABG neurologic and cognitive outcomes should focus more on patient-related risk factors rather than procedure-specific outcomes. (see also, Revised Guidelines for Evidence-Based PCI) Changing Perceptions on CABG & Cognitive Decline In the January 19, 2012 New England Journal of Medicine, my colleagues and I published a review article on neuro­cognitive outcomes following CABG. Studies in the past have suggested that CABG causes cognitive decline. For example, a Duke University study published about 10 years ago suggested a high rate of cognitive decline at 5 years after CABG. But this study was not randomized and had no control groups. In a more recent study (although not randomized), my colleagues at Johns Hopkins compared cognitive outcomes over 6 years in patients undergoing CABG, a group with the same vascular risk factors that did not undergo surgery, and a group of heart-healthy con­trols. Although those...