SCREENING CAROTID ULTRASONOGRAPHY AND RISK-FACTORS FOR STROKE IN CORONARY-ARTERY SURGERY PATIENTS

Background. The role of noninvasive carotid artery screening in relati on to other clinical variables in identifying patients at increased ri sk of stroke after coronary artery bypass grafting was examined. Metho ds. Preoperative, intraoperative, and postoperative clinical data were prospectively collected for 1,835 consecutive patients undergoing fir st-time isolated coronary artery bypass grafting between March 1990 an d July 1995, 1,279 of whom had screening carotid ultrasonography. All patients with postoperative neurologic events were identified and revi ewed in detail. Average patient age was 65.3 years (range, 33 to 92 ye ars), and 9.3% (171 patients) had a prior permanent stroke or transien t ischemic attack. Hospital and 30-day mortality was 2.2% (41 patients ). Forty-five patients (2.5%) had a transient or permanent postoperati ve neurologic event. The data were analyzed by stepwise logistic regre ssion to determine the independent predictors of both significant caro tid stenosis and stroke. Results. On multivariate analysis, the clinic al predictors of significant carotid stenosis were age (p < 0.0001), d iabetes ((p = 0.0123), female sex (p = 0.0026), left main coronary ste nosis greater than 60% (p < 0.0001), prior stroke or transient ischemi c attack (p = 0.0008), peripheral vascular disease (p = 0.0001), prior vascular operation (p = 0.0068), and smoking (p < 0.0001). When all v ariables were evaluated for those patients who underwent noninvasive c arotid artery screening, the independent predictors of postoperative n eurologic event were prior stroke or transient ischemic attack (p < 0. 0001), peripheral vascular disease (p = 0.0037), postinfarction angina pectoris (p = 0.0319), postoperative atrial fibrillation (p = 0.0014) , carotid stenosis greater than 50% (p = 0.0029), cardiopulmonary bypa ss time (p = 0.0006), significant aortic atherosclerosis (p = 0.0054), postoperative amrinone or epinephrine use (p = 0.0054), and left vent ricular ejection fraction less than 0.30 (p = 0.0744). Conclusions. Th e etiology of postoperative stroke is multifactorial. Selective use of carotid ultrasonography is of value in identifying patients who are a t greater risk of postoperative stroke independent of other variables and should be considered before coronary artery bypass grafting, parti cularly in patients with a history of neurologic event or peripheral v ascular disease.