Delirium: a cause for concern beyond the immediate postoperative period

Abstract

Background: Delirium is a common neurologic complication after cardiac surgery, and may be associated with increased morbidity and mortality. Research has focused on potential causes of delirium, with little attention to its sequelae.

Methods: Perioperative data were collected prospectively on all isolated cases of coronary artery bypass grafting (CABG) performed from 1995 to 2006 at a single center. The definition of delirium used in the study was that of the Society of Thoracic Surgeons. Characteristics of patients who became delirious postoperatively were compared with those of patients who did not. The outcomes of interest were long-term all-cause mortality, hospital admission for stroke, and in-hospital mortality, examined in all three cases through multivariate analysis.

Results: Of 8,474 patients who underwent CABG within the defined period, 496 (5.8%) developed postoperative delirium and 229 (2.7%) died while in the hospital. At baseline, patients who developed delirium were more likely to be older and to have a greater burden of comorbid illness. Delirium was an independent predictor of perioperative stroke (odds ratio [OR]; 1.96; 95% confidence interval [CI], 1.22 to 3.16), but was not associated with in-hospital mortality (OR, 0.81; 95%CI, 0.49 to 1.34). Delirious patients had a median postoperative hospital stay of 12 days (interquartile range [IQR], 8 to 21 days) versus 6 days (IQR, 5 to 8 days) for those who were nondelirious. Delirium was identified as an independent predictor of all-cause mortality (hazard ratio [HR], 1.52; 95%CI, 1.29 to 1.78) and hospitalization for stroke (HR, 1.54; 95%CI, 1.10 to 2.17).

Conclusions: There was an association between delirium and adverse outcomes after CABG that persisted beyond the immediate perioperative period. Patients with delirium after CABG appear to have an increased long-term risk of death and stroke. The advancing age and rising rates of delirium in the CABG population make it necessary to address the prevention and management of delirium in this population.