Predictors associated with stroke after coronary artery bypass grafting: a systematic review.

BACKGROUND: Stroke is a major cause of morbidity and mortality after coronary artery bypass grafting (CABG). The purpose of this systematic review was to evaluate the predictors of perioperative stroke after CABG.

METHODS: We reviewed the published literature on prognostic factors for perioperative stroke after CABG in articles using multivariate regression models. The statistical validity of prognostic models and a qualitative synthesis were performed.

RESULTS: We identified 14 studies. The methodological quality of study reporting was variable. Overall, the incidence of stroke after CABG was 1.1-5.7%. About 37-59% of strokes occurred early (intraoperatively). No validated stroke outcome scale was used to assess morbidity and mortality in any of the included studies. Advanced age, prior (before CABG) cerebrovascular disease/stroke, prior carotid artery stenosis, prior peripheral vascular disease, prior unstable angina, and prolonged cardiopulmonary bypass time were found to be the most consistent independent predictors of perioperative stroke after CABG. Postoperative atrial fibrillations were found to be the most consistent independent variables associated with postoperative stroke after CABG. No association was found with hypercholesterolemia, prior myocardial infarct, and smoking. Other risk factors, such as gender, prior hypertension, diabetes mellitus, congestive heart failure, and chronic renal failure, showed inconsistent results.

CONCLUSIONS: Seven variables (advanced age, prior cerebrovascular disease/stroke, prior carotid artery stenosis, prior peripheral vascular disease, prior unstable angina, prolonged cardiopulmonary bypass time, and postoperative atrial fibrillation), representing and high atherosclerotic burden, were found to be associated with more perioperative stroke events. Stroke assessment scales should be included to enable a detailed description of stroke morbidity post CABG. Lessons learned from the present study should also help to improve the quality and relevance of future studies on prognostic factors in stroke after CABG.