Investigating Characteristics of Post–Open-Heart Surgery Development of Delirium

According to Nikolai Hulde and colleagues from the Heart and Diabetes Center NRW in Bad Oeynhausen, Germany, there is a dearth of available data on the development of postoperative delirium in patients undergoing valvular open-heart surgery. The researchers retrospectively investigated the frequency, predictive factors, and short-term outcomes of delirium within a large cohort of patients undergoing valvular open-heart surgery. Their article, published in The Thoracic and Cardiovascular Surgeon, reported that postoperative delirium was a “frequent” neurological complication.

Moreover, the study’s authors observed that delirium was associated with other postoperative neurological complications, as well as several, “mostly nonmodifiable,” independent risk factors. Interestingly, the authors noted that, “although postoperative delirium was associated with a significantly increased risk of prolonged intensive care unit (ICU) stay, this did not translate into an increased short-term mortality.”

The analysis included a total of 13,229 patients undergoing valvular or combined valvular and bypass surgery. The occurrence of delirium was tracked until patient discharge, and independent risk factors (i.e., risk of an extended ICU stay and in-hospital mortality) were assessed via multivariable logistic regression.

According to the researchers, the overall incidence of postoperative delirium was 8.4%. Incidence was higher in patients who experienced a postoperative stroke or seizure at 23.1% and 29.7%, respectively. Multivariable analysis independently associated 12 preoperative factors with risk of delirium, including advanced age, renal impairment, stroke, the need for emergency surgery, and severe postoperative anemia (hemoglobin <9g/dL). The occurrence of postoperative delirium was also associated with an increase in adjusted risk of prolonged stay (>48 hours) in the ICU (odds ratio [OR], 9.48; 95% confidence interval [CI], 7.96–11.30). Lastly, as noted, the investigators found that adjusted in-hospital mortality was significantly lower in patients with delirium than in patients without (OR, 0.56; 95% CI, 0.38–0.83).

The authors presented this evidence to meet the need for data they identified for this challenging complication in valvular open-heart surgery. The association between occurrence of postoperative delirium and reduced in-hospital mortality could potentially suggest that hospital care for postoperative neurological complications may be alleviating an undefined contributor to mortality.