Outcomes following surgical revascularization with single versus bilateral internal thoracic arterial grafts in patients with left main coronary artery disease undergoing coronary artery bypass grafting: insights from the EXCEL trial†

Objectives: Observational data suggest that the use of a single internal thoracic artery (SITA) may result in inferior outcomes compared with bilateral internal thoracic artery (BITA) use for coronary artery bypass grafting (CABG)-a finding not yet supported by randomized trial outcomes. However, the optimal number of internal thoracic artery grafts in patients with left main coronary artery disease has not been investigated.

Methods: The EXCEL trial randomized 1905 patients with left main coronary artery disease to percutaneous coronary intervention with everolimus-eluting stents versus CABG. Among the 905 patients undergoing CABG, 688 (76.0%) received SITA and 217 (24.0%) received BITA. Differences in clinical event rates were estimated using the Kaplan-Meier method and compared with the log-rank test. Multivariable Cox regression was used to adjust for differences in baseline covariates.

Results: Compared to SITA, patients treated with BITA were younger (66.1 ± 9.5 vs 64.5 ± 9.3 years, P = 0.020), were less likely female (24.3% vs 14.3%, P = 0.002) and diabetic (28.8% vs 15.2%, P < 0.001), and had a lower prevalence of peripheral vessel disease (10.2% vs 5.5%, P = 0.040). The unadjusted 3-year composite primary endpoint of death, stroke or myocardial infarction (MI) occurred in 15.6% of SITA vs 11.6% of BITA patients (P = 0.17). The SITA group tended to have a higher 3-year rate of all-cause death compared with the BITA group (6.7% vs 3.3%; P = 0.070). Stroke, MI and ischaemia-driven revascularization outcomes were not significantly different between groups. After adjusting for baseline differences, neither the composite of death, stroke or MI [hazard ratio (HR) 1.12, 95% confidence interval (CI) 0.71-1.78; P = 0.62] nor mortality (HR 1.36, 95% CI 0.60-3.12; P = 0.46) was significantly higher with SITA. The rehospitalization rate after 3 years was higher in the SITA group (35.8% vs 26.0%, P = 0.008), a difference which was no longer present after multivariable adjustment (HR 1.27, 95% CI 0.93-1.74; P = 0.13). Sternal wound dehiscence within 30 days did not occur more often in the BITA group compared to the SITA group (1.8% vs 2.2%, P > 0.99).

Conclusions: In the EXCEL trial, there were no clinical differences at 3 years between SITA or BITA revascularization in patients with left main coronary artery disease.