Recurrent Seizures Following Cardiac Surgery: Risk Factors and Outcomes in a Historical Cohort Study

OBJECTIVES: To determine the risk factors for and outcomes after recurrent seizures (RS) in patients following cardiac surgery. DESIGN: A historical cohort study. SETTING: A single-center university teaching hospital. PARTICIPANTS: Cardiac surgery patients from April 2003 to September 2010 experiencing postoperative seizures. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were divided into an isolated seizure group and an RS group. Risk factors for RS were determined using logistic regression. Intermediate-term follow-up was conducted by phone. Of 7,280 consecutive patients undergoing cardiac surgery, 61 (0.8%) experienced postoperative seizure and 36 (59%) of those experienced at least 1 recurrence. Of these, 32 (89%) experienced RS within 24 hours of the first seizure, and 29 (81%) had grand mal seizures. Preoperative creatinine ≥120 μmol/L (p = 0.02), time until first seizure occurred (≤4 hours; p = 0.01), and procedures involving the thoracic aorta were associated with RS (R(2) = 0.53, p<0.05). Patients with RS had longer intensive care unit stays (5.3 v 2.9 days, p = 0.03) and longer mechanical ventilation duration (53.3 v 15.0 hours, p = 0.01). At a median follow-up of 21 months for the RS group and 16 months for the isolated seizure group, restrictions, anticonvulsant use, morbidity, and mortality were similar between patients with isolated versus recurrent seizures. CONCLUSIONS: Higher preoperative creatinine, thoracic aortic surgery, and early seizure onset were associated with RS after cardiac surgery. When compared to isolated seizures, recurrence per se was not associated with significantly increased long-term morbidity or mortality.