Elders undergoing cardiac surgery are at particular risk of postoperative cognitive dysfunction (POCD), an acute decline in cognition persisting days, weeks, or months following surgery. Nonetheless, thousands of elders undergo coronary artery bypass grafting (CABG) each year in the United States in hopes of improving their health and function. Percutaneous coronary intervention (PCI) offers coronary revascularization that avoids major surgery and anesthetic exposure, which may be an attractive alternative to CABG for elderly patients concerned about durable cognitive decline following CABG despite inferior revascularization outcomes for certain coronary lesions. It is not known whether long-term cognition, on the timescale of anticipated clinical benefit of CABG, is impacted differently by CABG versus PCI, and whether cognitive change is truly new or a continuation of preoperative cognitive trajectory. We propose an analysis of biennial cognitive testing in the Health and Retirement Study (HRS) linked with Medicare claims data to investigate population-level cognitive trajectories spanning up to 20 years in elderly patients undergoing CABG or PCI. Using linear mixed- effects models, we will model raw and adjusted pre- and post-revascularization cognitive trajectories for elders undergoing CABG and PCI to evaluate whether long-term population-level pre- and post-procedural cognitive trajectory for patients undergoing CABG differs from that for patients undergoing PCI. Furthermore, under the hypothesis that there is heterogeneity among post-procedure cognitive trajectories beyond that predicted by pre-procedure trajectory, we will identify subpopulations of patients united by clinical characteristics who are at elevated risk of POCD. Finally, to complement results derived from objective cognitive testing, we will also study the impact of CABG versus PCI on patient-reported (subjective) cognitive function and ability of the respondent to complete cognitively-intensive instrumental activities of daily living, like medication and financial management. This study will shed new light on the clinical relevance of POCD after coronary revascularization, providing data from a novel and patient-relevant perspective which will help clinicians reconcile the potential risks of cognitive change with the medical necessity of these interventions in elders at high risk for catastrophic coronary occlusive events.
This project will generate population- and individual-level data about cognitive change before and after heart procedures, which will help clinicians counsel older patients who need coronary revascularization and identify those at high risk of cognitive decline. Furthermore, this study will reconcile the research entity of ?postoperative cognitive dysfunction? with clinically-relevant estimates of cognitive change and the medical necessity of these interventions in elders with cardiac disease, advancing the National Institute on Aging's mission of promoting the health and well-being of older adults.
