COGNITIVE FUNCTION IN ELDERLY PATIENTS AFTER CARDIAC SURGERY: A SECONDARY ANALYSIS OF THE MINDDS TRIAL

Abstract

Postoperative cognitive dysfunction (POCD) is a common complication in elderly patients characterized by attention deficit, impaired memory and concentration that can last several months. POCD has been formally recognized as postoperative delirium (POD) if it occurs suddenly, together with altered consciousness, orientation, memory and inattention, typically lasting up to 3 days after surgery. In the first paper, we explored whether a sedative, dexmedetomidine, protects against future cognitive decline. The ensuing study assessed the tools used to measure cognitive decline with respect to POD and a focus on highlighting the usefulness of subjective measures.

Dexmedetomidine is a a sedative alpha-2 adrenergic agonist that has been used in clinical settings to provide sedation, anxiolysis, and analgesia during surgery. Its neuroprotective effects on the brain have been shown to be protective against POD after cardiac surgery, which suggests protection against long-term cognitive decline. We evaluated its effect on long term cognitive function and found no protection against cognitive decline six months after cardiac surgery. Cognitive function, however, is typically assessed using objective tools which may mask important relationships associated with subjective cognition and limit screening efforts for the true burden of cognitive decline.

Subjective cognitive decline (SCD) is the self-reported deterioration in cognitive function. We found that, consistent with objective cognitive function, POD was associated with SCD up to 180 days after surgery. This finding suggests that measures of SCD can be used at scale to screen cognitive decline associated with POD.