Older adults have similar rates of memory decline after undergoing coronary revascularization with coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI), a new study suggests. Researchers examined data on 1,680 adults 65 years and older who underwent CAGB (n=665) or PCI (n=1,015) between 1998 and 2015. The main goal of the study was data modeled changes in memory scores based on reports from the biennial Health and Retirement study, with a predetermined minimum clinically important difference set as a change bigger than at least one standard deviation of the level of memory decline in the population (0.048 memory units/year). Among patients who underwent PCI, the mean rate of memory decline was 0.064 memory units/year over the five years preceding the procedure and 0.060 memory units/year over the 10 years following the procedure, a change of 0.005 memory units/year. With CABG, the mean rate of memory decline was 0.049 memory units/year before the procedure and 0.059 memory units/year afterward, a change of 0.011 memory units/year. Overall, the difference in memory decline between PCI and CABG wasn't statistically significant. However, the mean change of 0.046 memory units/year found with off-pump CABG specifically was a statistically significant increase in the rate of memory decline relative to PCI, the researchers report in JAMA. "We were very surprised to find absolutely no difference between CABG and PCI, and more specifically between on-pump CABG and PCI, on the basis of long-term memory decline," said lead study author Dr. Elizabeth Whitlock, an assistant professor of anesthesia and perioperative care at the University of California, San Francisco School of Medicine. "CABG implies a lot of exposures that have been associated, or potentially associated, with memory problems: major surgery, the cardiopulmonary bypass pump, general anesthesia, opioids, recovery in the intensive care unit, intubation and mechanical ventilation, delirium - it's a huge list," Dr. Whitlock said by email. "So, to find absolutely no difference in average memory performance or probability of dementia out to the end of our modeling timeframe of 10 years was a big surprise." One limitation of the study is that the data modeling was based on population means, which include some individuals who improve and others who decline, the study team notes. Another limitation is that surgical techniques evolve over time, and it's possible that results from procedures done during the study period might not reflect what would happen today. However, CABG has been associated with a decline in cognitive function in some patients in studies dating back two decades, said Dr. Michael Rich, a professor of medicine at the Washington University School of Medicine in St. Louis who wasn't involved in the current study. "Before reading the study, I would have guessed that the patients undergoing CABG would have greater cognitive decline that those undergoing PCI - so I was surprised by the results that clearly demonstrate no difference between PCI and CABG with respect to rate of cognitive decline," Dr. Rich said by email. Clinicians should bear in mind that risk factors for heart disease, revascularization, stroke, and cognitive decline are similar, said Dr. Rebecca Gottesman, stroke branch chief at the National Institute of Neurological Disorders and Stroke and coauthor of an editorial accompanying the study. "Patients who need revascularization may be at risk for cognitive difficulties over time, but this risk is generally independent of what type of revascularization, or even if there is a revascularization at all," Dr. Gottesman, who co-authored the editorial while at Johns Hopkins University, said by email. "Controlling these risk factors such as hypertension, diabetes, smoking, high cholesterol and obesity is likely to reduce all of these risks," Dr. Gottesman added. —Lisa Rapaport Source
