The European bifurcation club Left Main Coronary Stent study: a randomized comparison of stepwise provisional vs. systematic dual stenting strategies (EBC MAIN)

Aim

To investigate in a randomized fashion the clinical outcomes in patients with distal bifurcation left main (LM) stem lesions undergoing percutaneous coronary intervention (PCI) with either a stepwise layered provisional stent strategy, or a systematic dual stenting strategy.

Methods

• Investigator-led study devised by and run through the European Bifurcation Club.
• Randomized, unblinded trial in 31 sites in 11 European countries.
• Patients with ‘true’ unprotected bifurcation LM coronary artery disease (Medina type 1,1,1 or 0,1,1—both main vessel and side vessel >50% narrowed).
• Patients were randomized to a stepwise layered provisional stent strategy, or a systematic dual stenting strategy.
• The primary endpoint of the study was a composite of all-cause death, myocardial infarction, and target lesion revascularization at 12 months.
• Secondary endpoints: the individual components of the primary endpoint, angina status, angina medication, and adjudicated stent thrombosis.

Results

• 467 patients with “true” unprotected LM disease were randomized
• The primary endpoint occurred in 14.7% of the stepwise provisional group vs. 17.7% of the systematic dual stent group (hazard ratio 0.8, 95% confidence interval 0.5–1.3; P = 0.34).
• Rates of death (3.0% vs. 4.2%, P = 0.48), myocardial infarction (10.0% vs. 10.1%, P = 0.91), target lesion revascularization (6.1% vs. 9.3%, P = 0.16), and stent thrombosis (1.7% vs. 1.3%, P = 0.90) did not differ between stepwise provisional group and the systematic dual stent group.

Main messages

Left main disease is one of the most challenging subset for PCI. When disease involves the distal bifurcation with all of the associated challenges of any bifurcation lesion with the exception that the side branch is a major epicardial vessel. Furthermore, the large mass of myocardium subtended by the LM may cause hemodynamic collapse during intervention. However, the debate on optimal percutaneous treatment of LM bifurcation is still ongoing. While some prior studies have suggested increased mortality with a dual-stent approach in true LM bifurcations, the randomized DKCRUSH-V trial demonstrated the opposite and formed the basis for a 2018 European Society of Cardiology recommendation that supports double-kissing crush over a planned provisional strategy.

Results from the presented EBC MAIN trial demonstrated no differences in the primary endpoint (all-cause death, myocardial infarction, and target lesion revascularization) between a stepwise layered provisional stent strategy versus a systematic dual stenting strategy at 1 year follow up. Furthermore, no significant disparities in any of the individual components of the primary endpoint. Also, the dual-stent group had longer procedure durations, fluoroscopy times, and higher X-ray doses. The choice of technique in the systematic planned two-stent group was at the discretion of the operator but could be one of culotte, DK-minicrush, T or TAP.

Intravascular imaging (IVI) especially in LM intervention helps operators to fully understand the anatomy, plan the procedure, and achieve optimal stent deployment. However, IVI guided PCI wasn’t mandated in the EBC MAIN study and was used in only 40% of cases (similar rate in both treatment strategies) which is similar to the DKCRUSH-V trial (41%). Therefore, the mandatory use of IVI might have influenced the rates of adverse events.

In summary, the results of this study indicates that patients are treated equally well with a stepwise layered provisional approach, starting with a single single stent, as with a more complex dual-stent implantation procedure. Therefore, it seems reasonable to conclude that the stepwise provisional strategy should remain the proffered approach for the majority of the left main bifurcation interventions.

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.