Some risk factors for post-CABG delirium, cognitive decline modifiable

Patients who undergo coronary artery bypass grafting (CABG) are at risk of developing subsequent delirium and cognitive decline, as reported in a study. But on the bright side, some of the key risk factors for the said neurological conditions are modifiable, including preoperative depression, diabetes, and hypertension.

The present study was based on a meta-analysis of 97 studies comprising data from 60,479 CABG patients (mean age, 64.54 years; 68.55 percent male). Seventeen of them were conducted in the US, 13 in Japan, nine in Canada, eight in Australia, and six each in China and the Netherlands. The remaining 38 studies were conducted across 22 different countries. Study quality was good according to critical appraisals, with a median score of 10 (0–12 scale, where higher scores indicated greater overall quality).

Pooled data from 48 studies evaluating delirium following CABG revealed moderate to large effect sizes and statistically significant estimates for the following risk factors: (1) preoperative cognitive impairment, depression, stroke history, and higher European System for Cardiac Operative Risk Evaluation (EuroSCORE) score, (2) intraoperative increase in intubation time, and (3) postoperative presence of arrythmia and increased days in the intensive care unit. Of note, better preoperative cognitive performance was protective against delirium.

Meanwhile, summary data from 35 studies investigating the presence of acute cognitive decline (immediately up to 1 month) post‐CABG yielded significant estimates for the following risk factors: (1) preoperative depression and older age, (2) intraoperative increase in intubation time, and (3) postoperative presence of delirium and increased days in the intensive care unit. Preoperative depression had a moderate effect size for midterm (1–6 months) post‐CABG cognitive decline.

Heterogeneity of results across the analyses ranged from low to high. There was potential small‐study effect seen in two analyses, where trim and fill estimation led to decreases in effect size.

The findings suggest that improving the management of depression, diabetes mellitus, and hypertension in a preoperative setting may help prevent the incidence of delirium and cognitive decline in CABG patients. A CABG‐specific risk tool could be developed and used to improve prognosis.