Assessment of the emergence of Alzheimer's disease following coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty1

Post-Operative Cognitive Decline (POCD) is a complication of Coronary Artery Bypass Graft (CABG) surgery and is consistent with reduced neuronal reserve. We performed a retrospective cohort analysis of Veterans Affairs (VA) patients undergoing CABG or PTCA between October 1, 1996 and September 30, 1997 to examine if CABG surgery is associated with the earlier emergence of cognitive impairment such as Alzheimer's Disease (AD). The emergence of dementia following CABG surgery was compared to dementia in a cardiac population undergoing percutaneous transluminal coronary angioplasty (PTCA). Patients were followed from the date of their procedure until September 30, 2002, the diagnosis of Alzheimer's disease or death. Cox proportional hazards models were used to compare the risk of AD development. Patients analyzed were > or = 55 yrs old without baseline dementia. The results show that a total of 119 patients (CABG = 78; PTCA = 41) developed AD during the follow-up period. The adjusted risk of AD associated with CABG versus PTCA was 1.71 (95% CI, 1.02 to 2.87; p = 0.04). These results suggest that patients undergoing CABG surgery were at increased risk for the emergence of AD than those undergoing PTCA. These data support the hypothesis that CABG surgery is associated with a reduced neuronal reserve in an aging population.