Predictors of early and late stroke following cardiac surgery

Much is known about the short-term risks of stroke following cardiac surgery. We examined the rate and predictors of long-term stroke in a cohort of patients who underwent cardiac surgery.

We obtained linked data for patients who underwent cardiac surgery in the province of Ontario between 1996 and 2006. We analyzed the incidence of stroke and death up to 2 years postoperatively.

Of 108,711 patients, 1.8% (95% confidence interval [CI] 1.7%-1.9%) had a stroke perioperatively, and 3.6% (95% CI 3.5%-3.7%) had a stroke within the ensuing 2 years. The strongest predictors of both early and late stroke were advanced age (≥ 65 year; adjusted hazard ratio [HR] for all stroke 1.9, 95% CI 1.8-2.0), a history of stroke or transient ischemic attack (adjusted HR 2.1, 95% CI 1.9-2.3), peripheral vascular disease (adjusted HR 1.6, 95% CI 1.5-1.7), combined coronary bypass grafting and valve surgery (adjusted HR 1.7, 95% CI 1.5-1.8) and valve surgery alone (adjusted HR 1.4, 95% CI 1.2-1.5). Preoperative need for dialysis (adjusted odds ratio [OR] 2.1, 95% CI 1.6-2.8) and new-onset postoperative atrial fibrillation (adjusted OR 1.5, 95% CI 1.3-1.6) were predictors of only early stroke. A CHADS2 score of 2 or higher was associated with an increased risk of stroke or death compared with a score of 0 or 1 (19.9% v. 9.3% among patients with a history of atrial fibrillation, 16.8% v. 7.8% among those with new-onset postoperative atrial fibrillation and 14.8% v. 5.8% among those without this condition).

Patients who had cardiac surgery were at highest risk of stroke in the early postoperative period and had continued risk over the ensuing 2 years, with similar risk factors over these periods. New-onset postoperative atrial fibrillation was a predictor of only early stroke. The CHADS2 score predicted stroke risk among patients with and without atrial fibrillation.