Perioperative Neurocognitive Disorders in Elderly Patients Undergoing Cardiac Surgery: Mechanisms, Biomarkers, and Prevention.

Perioperative neurocognitive disorders (PNDs), which primarily encompass postoperative delirium and postoperative cognitive dysfunction, represent common and severe complications in elderly patients undergoing cardiac surgery. These disorders not only lengthen hospital stays and increase morbidity but also significantly impact long-term cognitive status and overall quality of life. The pathophysiology of PNDs is multifactorial, involving mechanisms such as neuroinflammation, cerebral hypoperfusion, and neurodegenerative changes. Older age, prior cognitive impairment, cerebrovascular comorbidities, and genetic influences are major risk factors. Current evidence has shown that biomarkers, ranging from peripheral blood to neuroimaging detection, enable early detection and individualized risk assessment. Prevention and management strategies, such as preoperative cognitive assessment, intraoperative cerebral oxygenation monitoring, and postoperative multimodal analgesia, have shown promise. Despite these developments, the pathophysiology of PNDs remains incompletely understood. This review was designed to provide a concise summary of the literature on PNDs, including mechanisms, biomarkers, and prevention, and to offer insights into directions for future research. By highlighting knowledge gaps and delivering evidence-based prevention strategies, this review seeks to improve patient outcomes and reduce societal costs associated with cognitive impairment among elderly cardiac surgery patients.