Purpose: To evaluate whether the presence of stenosis or an occluded internal carotid artery (ICA) influences perioperative stroke and mortality rates in patients subjected to coronary artery bypass grafting (CABG).
Material and methods: Between January 1995 and July 1998, 3,344 patients (59% males; 41% females) had CABG performed at our institution. Preoperative carotid duplex scans performed by registered vascular technologists at an ICAVL accredited laboratory were available for review in all patients. Of these, 3,101 (92.7%) had < 60% ICA stenosis (group A), 182 (5.4%) had 60% to 99% ICA stenosis (group B), and the remaining 61 (1.8%) had a occluded ICA (group C). In the latter group, 53 patients (87%) had < 60% contralateral ICA stenosis, while 8 (13.1%) had significant (60% to 99%) contralateral stenoses. Concomitant carotid endarterectomies (CEAs) were performed in 70 patients in group B (40%) and in 2 patients in group C (3.2%). Age, indications for surgery, prevalence of diabetes, hypertension, and smoking were similar in all groups. The mean pump time for groups A, B and C were 132, 138, and 125 minutes, respectively. The aortic cross-clamp time for group A, B, C were 78, 75, and 75 minutes, respectively. Statistical analyses were performed using the chi-square, Fisher's exact test, and unpaired t test.
Results: Perioperative stroke rates (30 days) were 1.6%, 3.8%, and 6.5% for groups A, B, and C, respectively. Group A results varied significantly from groups B (P < 0.03) and C (P < 0.003). No statistically significant difference was noted between groups B and C (P = 0.6). The presence of a contralateral ICA stenosis in group C patients was predictive of a perioperative stroke (25% versus 3.8%; P < 0.0001). Concomitant CEAs for contralateral severe ICA stenosis in group C were associated with higher stroke rate (100%) when compared with those in group B patients (4.2%; P < 0.02). Perioperative (30 days) mortality rates for groups A, B, and C were 3.6%, 6.6%, and 8.6%, respectively. The mortality rate for group A was lower than for groups B (P < 0.05) and C (P < 0.05).
Conclusion: The presence of an ICA occlusion increases the morbidity and mortality in patients undergoing CABG. To the best of our knowledge, this is the first reported large series of patients that investigates the role of carotid occlusions.