Patterns of Restenosis After Left Main Bifurcation Single- or Dual-Stenting: An EBC MAIN Trial Subanalysis

Background: In the randomized EBC MAIN trial (European Bifurcation Club Left Main Coronary Stent), target lesion revascularization at 3 years poststenting of left main (LM) bifurcations was more frequent with upfront dual-stenting compared with the stepwise provisional approach. Restenosis location and its relation to stent technique are poorly characterized. The aim of this study was to investigate restenosis location after LM bifurcation stenting, and the impact of stent implantation technique. Methods: Patients from the EBC MAIN trial who underwent target lesion revascularization during the 3-year follow-up had restenosis location assessed by the core laboratory. Restenosis was defined as ≥50% lesion diameter stenosis. Results: Among 48 patients with target lesion revascularization (mean age 70.3±10.6 years, 72.9% male), 31 were randomized to and treated with upfront dual-stenting, while 17 were randomized to the stepwise provisional technique, of whom 4 had dual-stent implantation. The treatment groups therefore comprised 35 dual-stented and 13 single-stented patients. The commonest pattern of subsequent restenosis was isolated ostial circumflex restenosis (58% of patients), regardless of dual- or single-stent implantation. The ostial circumflex was the culprit lesion for target lesion revascularization in 34 (71%) patients overall (dual- versus single-stented patients: 77% versus 54%; P=0.115). During the 3-year follow-up, the mean % diameter stenosis at the circumflex ostium was similar after dual- versus single-stent implantation (64.6% versus 60.5%, coefficient, -0.12 [95% CI, -0.46 to 0.22]; P=0.473). Single stenting from LM to the circumflex artery was associated with worse subsequent mean % diameter stenosis in the ostium of the left anterior descending artery versus single stenting from LM- left anterior descending (49.8% versus 19.8%, coefficient, 0.57 [95% CI, 0.003-1.13]; P=0.049). Conclusions: The circumflex ostium is the commonest site requiring revascularization after LM bifurcation stenting, irrespective of whether 1 or 2 stents were deployed. Strategies are needed to improve the long-term success of percutaneous coronary intervention to the circumflex artery ostium. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02497014.