Hypothesis:

Simple crossover strategy would be non-inferior to SB opening strategy in the risk of target lesion failure (TLF) in patients with angiographically compromised SB (visually SB stenosis ≥50%) after provisional MV stenting for non-left main bifurcation lesion.

A total of 1000 patients (500 per each group) with the angiographically compromised SB (visually SB stenosis ≥50%) after provisional MV stenting for non-left main bifurcation lesion will be enrolled. Patients will be randomized to either the simple crossover strategy group or SB opening strategy group at the time of enrollment with 1:1 ratio. Stratified randomization according to participating center, clinical presentation (acute coronary syndrome or stable ischemic heart disease), and type of bifurcation lesions (true or non-true) will be performed.

Despite advances in stenting techniques and devices, percutaneous coronary intervention (PCI) for bifurcation lesions remains one of the most challenging and complex procedures. Current guidelines recommend 1-stenting with provisional side branch (SB) approach should be an initial treatment strategy for the bifurcation lesions, based on the previous results of several randomized trials. However, the standardization of the provisional strategy is limited. In particular, there is a recommendation on the treatment technique for SB when SB intervention is required, but It has not been decided in which cases SB treatment is necessary, in the latest European Bifurcation Club (EBC) consensus document.16 In previous studies, the criteria for performing SB opening after MV stent intervention in the 1-stenting with provisional SB approach were varied. In the DK-CUSH II (Double Kissing Crush versus Provisional Stenting Technique for Treatment of Coronary Bifurcation Lesions) or CACTUS (Coronary Bifurcations: Application of the Crushing Technique Using Sirolimus-Eluting Stents) trials, SB intervention was performed when the SB diameter stenosis more than 50%, grade B or higher dissection, or blood flow disturbance (TIMI flow 2 or less) after MV stent insertion. On the other hand, in the Nordic trial, the authors applied strict criteria for SB intervention after MV stent insertion (TIMI flow 2 or less only). Furthermore, there have been conflicting results regarding the clinical and angiographic outcomes of the jailed SB opening strategy after the main vessel (MV) stenting, compared with the simple crossover strategy for non-left main bifurcation lesion.

On this background, this trial aims to compare the clinical outcomes between simple crossover and side branch opening strategies in patients with the angiographically compromised SB (visually SB stenosis ≥50%) after provisional MV stenting for non-left main bifurcation lesion.

Inclusion Criteria:

• (1) Subject must be at least 19 years of age
• (2) Patients with non-left main bifurcation lesion (SB diameter ≥2.3 mm)
• (3) Target lesions amenable for 1-stenting with provisional SB approach by operators' decision
• (4) Angiographically compromised SB (visual SB stenosis ≥50%) after provisional MV stenting

Exclusion Criteria:

• (1) Target lesions requiring elective 2-stenting technique by operators' decision (Observation Group 1)*

• (2) Patients who inevitably require SB intervention after MV stenting, as follows. (Observation Group 2)*

  1. Reduced SB TIMI flow (≤2) after MV stenting
  2. SB dissection after MV stenting (≥ Type C)

• (3) Patients without SB compromise after MV stenting (visually SB stenosis <50%) (Observation Group 3)*

• (4) Cardiogenic shock (Killip class IV) at presentation

• (5) Patients with significant valvular heart disease or severe left ventricular systolic dysfunction (ejection fraction <35%)

• (6) Pregnancy or breast feeding

• (7) Non-cardiac co-morbid conditions are present with life expectancy <1 year or that may result in protocol non-compliance (per site investigator's medical judgment)

• (8) Unwillingness or inability to comply with the procedures described in this protocol