Predictors of Stroke After Cardiac Surgery

Abstract

From January 1, 1988 to September 30, 1993, 44 of 2,455 patients undergoing cardiac surgery for acquired heart disease at our institution sustained an intraoperative or postoperative cerebrovascular accident (CVA). Demographic data, atherosclerosis risk factors, past medical history, cardiac catheterization reports, and intraoperative findings were retrospectively reviewed. The highest rate of CVA was in the sub-group of patients undergoing simultaneous myocardial revascularization and carotid endarterectomy (18.2%). The lowest rate was in a group of patients who underwent aortic valve replacement (0.9%). Severe aortic arch atherosclerosis with the presence of atheromatous material or calcinosis at the cannulation site was identified intraoperatively in 43.2% of patients with neurological complications and in 5% of the group without CVA (x²= 18.1, p = 0.0001). Of 44 patients with CVA, 13.6% had a history of preoperative completed stroke. CPB time was 90.1 ± 4.9 min vs. 71.6 + 3.7 min (p = 0.004), and aortic cross-clamping time was 54.5 ± 3.2 min compared to 39.8 ± 2.7 min (p = 0.001) in groups with and without postoperative stroke, respectively. Hypertension was an independent risk factor of postoperative CVA (x²= 9.5, p = 0.02), but age was not. Neurological complications correlated with high operative mortality (38.6%) and prolonged postoperative hospital stays (35.1 ± 5.3). These data describe predictors for the development of post-cardiopulmonary bypass CVA and identify a high-risk subgroup for neurological events. The preoperative recognition of risk factors is an essential step toward the reduction of morbidity and mortality.