Predictors of cerebrovascular events in patients subjected to isolated coronary surgery. The importance of aortic cross-clamping.

OBJECTIVE Stroke is a major complication after coronary surgery, occurring in 1-4% of the patients. In this study, we evaluate the incidence and pre- and intraoperative risk factors for the development of a cerebrovascular accident (CVA) and the impact of such an event on perioperative mortality and on hospital length of stay. METHODS Data from 4567 patients submitted to isolated coronary artery bypass grafting (CABG) with hypothermic ventricular fibrillation between 1992 and 2001 were entered prospectively into a dedicated computerized database and analyzed retrospectively at this time. Univariate and multivariate analyses were performed where appropriate. RESULTS The incidence of postoperative CVA was 2.5% (116 patients). Multivariable logistic regression identified the following variables to be independent predictors of a postoperative CVA: cerebrovascular disease (P<0.001; odds ratio (OR), 2.66), peripheral vascular disease (P<0.001; OR, 2.33), number of periods of aortic cross-clamping (P=0.019; OR, 1.31 per each period of aortic cross-clamping), LV dysfunction (P=0.012; OR, 1.82) and age (P=0.008; OR, 1.28 per each 10 years). Non-elective surgery showed a marginal significance (P=0.08; OR 1.83). The 30-day mortality for patients who experienced a CVA was 16.4% versus 0.6% for patients who did not (P<0.001). Postoperative CVA increased the length of hospital stay threefold to 20.3+/-28.3 days as compared with patients who did not have a postoperative CVA (7.6+/-4.2 days; P<0.001). CONCLUSIONS Postoperative CVA dramatically increases the mortality and length of stay after CABG. Identification of predisposing factors permits preoperative risk stratification and may facilitate improved patient selection or optimization. Our study adds evidence to the superiority of the fibrillation technique over intermittent cross-clamping of the aorta, among non-cardioplegic techniques, in terms of neurological protection.