Continuing controversy in the management of concomitant coronary and carotid disease: an overview

Abstract

Objectives: To perform an analytical overview of the risk factors, pathogenesis of stroke and the strategies for the management of concomitant coronary artery disease and carotid artery stenosis (CAS). Four strategies were analysed; CABG in the presence of CAS, combined (CE+CABG), reverse (CABG+CE<3 months) and prior staged (CE+CABG<3 months).

Methods: A literature search formed the basis of a reference database. Outcome was assessed by the 30-day permanent stroke and mortality rate for the different approaches. Accrued rates of permanent stroke and mortality rate were expressed in terms of mean stroke and mortality rate (MSR, MMR). Data was analysed comparatively and expressed in terms of P value, odds ratio and confidence limits.

Results: 33 different risk factors for stroke at CABG were identified. Significant factors included: ascending aortic atheroma, emergency procedures, impaired left ventricular function, cardioplegia and peripheral vascular disease. Risk of stroke at CABG increased with higher grade CAS (50 vs. 80%, P=0.009). Pathogenesis of stroke at CABG is multifactorial; the role of flow limiting CAS is controversial and other mechanisms are implicated. Analysis of the four strategies revealed that in the Prior Stage (n=573) the MSR was 1.5% and MMR 5.9%, in the Unprotected CABG+CAS series the MSR was 3.8% (n=840) and MMR (n=596) 4.4%, in the Reverse stage series (n=83) the MSR was 2.4%, and MMR 4.8%. For Combined procedures (n=3,295) the MSR was 3.9% and MMR 4.5%. Comparative analysis indicated a significant reduction in stroke for Prior vs. Combined (1.5 vs. 3.9%, P=0.007, odds 0.39, CI 0.2-0.77) with a higher mortality (5.9 vs. 4.5%, P=0.1, odds 1.41, Cl 0.96-2.06, NS). The stroke rate in the Prior stage also remained significantly lower compared to the Unprotected CABG group both mixed (P=0.015) and asymptomatic CAS (P=0.047). When total risks (MSR+MMR), were analysed, similar results were found between the groups; Prior 7.4%, Reverse stage 7.2%, Combined 8.4%, Unprotected CABG+ >50% CAS 11.5%.

Conclusions: Stroke at CABG is due to multiple risk factors, one of which is high-grade carotid stenosis. Pathophysiology of stroke, although multifactorial, supports embolism rather than flow limitation as the primary mechanism. Lack of randomised trials has made it impossible to draw firm conclusions regarding the best management strategy. There was no significant difference in the overall stroke and mortality risk between the various strategies, however, subgroup analysis suggests that, when carefully selected, patients do better by staging the operations. In our opinion patients without severe cardiac disease should be considered for Prior staging and the rest for Combined procedure. The role of reverse staging needs further evaluation.