Association of neurocognitive function and quality of life 1 year after Coronary Artery Bypass Graft (CABG) surgery

OBJECTIVE: Although coronary artery bypass grafting (CABG) has been shown to improve quality of life and functional capacity for many patients, recent studies have demonstrated that a significant number of patients exhibit impairment in cognitive function immediately following surgery and beyond. We sought to determine the impact of this postoperative cognitive dysfunction on quality of life (QOL) and to characterize the dysfunction from the patient's perspective. METHODS: With Institutional Review Board (IRB) approval and written informed consent, 732 patients at Duke University Hospital undergoing CABG were enrolled. Five hundred fifty-one (75%) completed baseline, 6-week, and 1-year neurocognitive tests and psychometric measures designed to assess QOL. Neurocognitive status was assessed by a composite cognitive index score representing the mean of the scores in four cognitive domains. Change in QOL was assessed by subtracting baseline from 1-year scores for each of 10 QOL measures. The association between QOL and cognitive dysfunction was investigated using multivariable linear regression analysis. RESULTS: Cognitive decline limited improvement in QOL, with substantial correlation between change in cognition and change in QOL. One-year QOL measures are associated with both 6-week and 1-year change in cognition (Instrumental Activities of Daily Living, p < .0001; Duke Activity Status Index, p < .02; Cognitive Difficulties, p < .0001; Symptom Limitations, p = .0001; Center for Epidemiologic Study Depression, p < .0001; General Health Perception, p = .0001). CONCLUSIONS: Postoperative cognitive decline may diminish improvements in QOL. Strategies to reduce cognitive decline may allow patients to achieve the maximum improvement in QOL afforded by CABG, as even short-term cognitive dysfunction has implications for QOL 1 year later.