Cognitive trajectories after postoperative delirium.


Delirium is common after cardiac surgery (46% of patients in this study), and is associated with prolonged cognitive impairment.


  • N=225 patients ≥60 years old (average age = 73), scheduled for coronary-artery bypass graft or valve replacement.
  • Delirium assessed by Confusion Assessment Method.
  • Cognitive function assessed with Mini-Mental State Examination (MMSE, score range 0-30, higher better).
  • Assessments done preoperatively and daily starting on postoperative day 2 through hospitalization, then at 1, 6 and 12 months after surgery.


  • Delirium developed in 103 patients (46%) after surgery.
  • Delirium was associated with lower preoperative MMSE score (P<0.001):
    • Delirium: 25.8
    • No Delirium: 26.9
  • MMSE at 1 month (P<0.001):
    • Delirium: 24.1
    • No Delirium: 27.4
  • MMSE at 1 year (P<0.001):
    • Delirium: 25.2
    • No Delirium: 27.2
  • After adjusting for baseline, those with delirium had significantly lower MMSE at 1 month (P<0.001) but not significantly lower at 6 months (P=0.056) or 12 months (P=0.056).


Saczynski JS, Marcantonio ER, Quach L, et al. Cognitive trajectories after postoperative delirium. N Engl J Med. 2012;367(1):30-39. doi:10.1056/NEJMoa1112923.

View on PubMed