Incidence, Topography, Predictors and Long-Term Survival After Stroke in Patients Undergoing Coronary Artery Bypass Grafting

Abstract

Previous studies on stroke after coronary artery bypass grafting (CABG) provide limited data about the timing (early vs delayed) of this event and findings of brain imaging analysis. This information is of significant importance because it provides insight into the etiology of stroke, potentially allowing the development of preventive measures. This study analyzed the incidence and timing of stroke, the topography and mechanisms of cerebral lesions, independent predictors, and late outcome after the occurrence of this complication in patients undergoing CABG. We retrospectively analyzed prospectively collected data from 2985 patients (2064 men [67%]), with a mean age of 66 +/- 11 years, who underwent CABG between January 1998 and December 2006. Stroke was defined as any new permanent focal neurologic deficit (early stroke, < or = 24 hours; delayed, > 24 hours postoperatively). The incidence of stroke was 1.6% (n = 48) and similar between conventional CABG (1.6%) and off-pump CABG (1.4%). Early stroke occurred in 25 patients (52%). Brain imaging was obtained in 44 patients (92%): 44 had computed tomography, 3 had magnetic resonance imaging. Results were positive in 33 of 44 patients (75%), showing large embolic stroke in 25 (76%), watershed in 5 (15%), and mixed pattern in 3 (9%). Chronic ischemic changes were found in 17 patients. Multivariate analysis revealed extensive aortic calcification (odds ratio [OR], 4.2), previous stroke (OR, 2.2), female sex (OR, 1.9), and congestive heart failure (OR, 2.6) as predictors of stroke. The hospital mortality rate after stroke was 16.7% (n = 8) compared with 1.5% (n = 44) in those without (p < 0.001). The mortality rate was higher in early stroke at 24% (6 of 25) compared with 9% (2 of 23) in late stroke. Survival of stroke patients was 87% at 1 year and 62% at 5 years and was significantly reduced compared with 96% and 85%, respectively, in patients without stroke (p<0.001). Most strokes after CABG occurred early after surgery. This complication is associated with an increased hospital mortality and morbidity and reduced long-term survival. The infarction type had no impact on early and late outcome. Preoperative computed tomography scan seems warranted in patients at risk and without any previous history of stroke.