Stepwise Provisional Versus Systematic Dual-Stent Strategies for Treatment of True Left Main Coronary Bifurcation Lesions

Background: The optimal coronary stenting technique for true left main bifurcation lesions is uncertain. EBC MAIN (European Bifurcation Club Left Main Trial) aimed to evaluate clinical outcomes of a stepwise provisional strategy compared with a systematic dual-stent approach. Methods: EBC MAIN was a randomized, investigator-initiated, open-label, multicenter, parallel-group trial conducted across 35 hospitals in 11 European countries. A total of 467 participants undergoing percutaneous coronary intervention for unprotected true left main bifurcation lesions were randomly assigned to the stepwise provisional strategy (n=230) or an upfront dual-stent approach (n=237). The mean (SD) age was 71 (10) years and 23% of participants were women. The primary end point was a composite of major adverse cardiac events, defined as all-cause mortality, all myocardial infarction, or clinically driven target lesion revascularization. Events were adjudicated by an independent clinical events committee and all analyses were by the intention-to-treat principle. Results: At 3 years, the primary end point occurred in 54 of 230 (23.5%) stepwise provisional and 70 of 237 (29.5%) dual-stent patients (hazard ratio, 0.75 [95% CI, 0.53-1.07]; P=0.11). There was no significant difference in all-cause mortality (10.0% versus 13.1%) or myocardial infarction (12.2% versus 11.0%). However, target lesion revascularization was significantly lower in the stepwise provisional group (8.3% versus 15.6%; hazard ratio, 0.50 [95% CI, 0.29-0.86]; P=0.013). In this population, the mean side vessel diameter by quantitative angiography was 2.9 mm, and median side vessel lesion length was 5 mm. Significant interactions were identified between the assigned bifurcation strategy and both side vessel diameter and lesion length with respect to the primary outcome (P=0.009 and P=0.005, respectively), with smaller vessels (<3.25 mm diameter) and shorter lesions (<10 mm length) favoring the provisional approach. Conclusions: In a European population with true left main stem bifurcation coronary disease requiring intervention, there was no difference in major adverse cardiovascular events between stepwise provisional and systematic dual-stent strategies at 3 years. Target lesion revascularization was significantly less frequent with the stepwise provisional approach, which should be the default strategy for noncomplex left main bifurcation coronary intervention. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02497014.