Frequency and predictors of cognitive decline in patients undergoing coronary artery bypass graft surgery.

Objective: To determine the frequency of cognitive impairment and its predictors in patients, who underwent first time coronary artery bypass graft surgery (CABGS).

Study Design: An observational study.

Place And Duration Of Study: The National Institute of Cardiovascular Diseases (NICVD), Karachi, from December 2008 to December 2009.

Methodology: Study included patients > 18 years, who underwent first-time elective CABGS. Emergency CABGS, with additional cardiac procedures, myocardial infarction (MI) within one month and known psychiatric illness were excluded. Patients were evaluated for their socio-demographic profile, medical history, intra-operative, anesthetic and surgical techniques and postoperative complications/therapy in ICU. Cognitive functioning, before the surgery, at discharge, 6 weeks and 6 months post-CABG was evaluated by McNair's and MMSE scales. HDRS was added to see if depression was a confounding factor for cognitive decline.

Results: One hundred and thirty four patients were followed-up at discharge, 74 at 6 weeks and 73 at 6 months. There were 113 (84.3%) males and 21 (15.7%) females, with mean age of 53.7 ± 8.36 years. Prevalence of cognitive disturbance at baseline was 44.8%, which increased to 54.5% at discharge, and improvement was seen at 6 months, it was 39.7%. Older age, female gender, higher bleeding episodes, and high post-surgery creatinine level were more frequently associated with cognitive decline.

Conclusion: Postoperative cognitive deficit was common and remained persistent at short-term. Older age, females and high postoperative creatinine were identified as its important predictors. There was high frequency of acute depression before surgery with significant reduction over time.