Safety of Simultaneous Coronary Artery Bypass Grafting and Carotid Endarterectomy Versus Isolated Coronary Artery Bypass Grafting: A Randomized Clinical Trial

Abstract

Background and purpose: The optimal operative strategy in patients with severe carotid artery disease undergoing coronary artery bypass grafting (CABG) is unknown. We sought to investigate the safety and efficacy of synchronous combined carotid endarterectomy and CABG as compared with isolated CABG.

Methods: Patients with asymptomatic high-grade carotid artery stenosis ≥80% according to ECST (European Carotid Surgery Trial) ultrasound criteria (corresponding to ≥70% NASCET [North American Symptomatic Carotid Endarterectomy Trial]) who required CABG surgery were randomly assigned to synchronous carotid endarterectomy+CABG or isolated CABG. To avoid unbalanced prognostic factor distributions, randomization was stratified by center, age, sex, and modified Rankin Scale. The primary composite end point was the rate of stroke or death at 30 days.

Results: From 2010 to 2014, a total of 129 patients were enrolled at 17 centers in Germany and the Czech Republic. Because of withdrawal of funding after insufficient recruitment, enrolment was terminated early. At 30 days, the rate of any stroke or death in the intention-to-treat population was 12/65 (18.5%) in patients receiving synchronous carotid endarterectomy+CABG as compared with 6/62 (9.7%) in patients receiving isolated CABG (absolute risk reduction, 8.8%; 95% confidence interval, -3.2% to 20.8%; P_WALD=0.12). Also for all secondary end points at 30 days and 1 year, there was no evidence for a significant treatment-group effect although patients undergoing isolated CABG tended to have better outcomes.

Conclusions: Although our results cannot rule out a treatment-group effect because of lack of power, a superiority of the synchronous combined carotid endarterectomy+CABG approach seems unlikely. Five-year follow-up of patients is still ongoing.

Clinical trial registration: URL: https://www.controlled-trials.com. Unique identifier: ISRCTN13486906.

Keywords: carotid stenosis; coronary artery bypass; endarterectomy, carotid; randomized controlled trial; stroke.

Figure 1.

CONSORT flow diagram (Consolidated Standards of Reporting Trials) of patients in the CABACS (Coronary Artery Bypass Graft Surgery in Patients With Asymptomatic Carotid Stenosis) trial. CABG indicates coronary artery bypass grafting; and CEA, carotid endarterectomy.

Figure 2.

Secondary end points at 30 days and 1 year (forest plot of risk ratios and hazard ratios plotted on a logarithmic scale). ¹For day 30 and year 1, absolute and relative frequencies; for time-to-event analysis, 1-year Kaplan–Meier estimates; for length of hospital and ICU stay, mean and SD. ²For day 30 and year 1, relative risk; for time-to-event analysis, unadjusted hazard ratios for treatment variable from Cox proportional hazards regression; missing effect sizes either not available or not calculated; ³Confirmatory analysis of the primary endpoint was based on the Wald test statistic; for day 30 and year 1, exact Monte Carlo estimation for χ² test P values; for time-to-event analysis, log-rank test P values; for DemTect scale difference, length of hospital stay and ICU stay exact Wilcoxon–Mann–Whitney test P values. ⁴Technical failure of intervention can only be measured for the synchronous carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) arm. CI indicates confidence interval.

Figure 3.

Kaplan–Meier estimates of survival free from stroke or vascular death up to 1 year in the intention-to-treat population (P_log-rank=0.30). CABG indicates coronary artery bypass grafting; and CEA, carotid endarterectomy.