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.