From heart to mind: A narrative review of incidence, risk factors, and mechanisms of dementia after cardiac surgery.

As cardiac surgery becomes more common, concerns about postoperative cognitive decline and the potential progression to dementia have grown. While postoperative cognitive dysfunction (POCD) is well documented, its relationship to long-term dementia risk remains unclear. We narratively summarize evidence on dementia incidence, diagnostic approaches, risk factors, and pathophysiological mechanisms. Across the literature, dementia incidence after cardiac surgery varied between 1.5% and 30.8% over 1 to 24 years of follow-up, reflecting heterogeneous patient populations, surgical procedures, follow-up durations, and diagnostic criteria. Consistent risk factors included older age, preoperative mild cognitive impairment, cardiovascular comorbidities, and postoperative delirium. Proposed mechanisms involved cerebral microembolism, systemic inflammation, hypoxia-ischemia, and impaired cerebral autoregulation. Future research would benefit from standardized diagnostic criteria, consistent incidence reporting, and long-term, multicenter studies to refine risk estimates. Identifying modifiable perioperative factors through targeted screening and prevention strategies may preserve cognition and improve long-term outcomes after cardiac surgery.