Single-stent strategy with provisional approach represents the gold standard for percutaneous coronary intervention of bifurcation lesions, and, according to European Bifurcation Club, performing provisional approach presents two steps considered as mandatory: "crossover stenting" in main vessel (MV) and subsequent post-dilation or "POT" (proximal optimization technique). While consensus exists regarding these first two steps, the exact optimal following sequence in case of side branch (SB) jeopardize after main vessel stenting is still a matter of debate.

Actually, the two most used techniques in this setting are represented by the simultaneous inflation of two balloons located respectively in the MV and SB followed by a second POT (POT/kissing balloon/POT technique) and the isolated inflation of a balloon placed in the SB followed by a second POT (POT/SIDE/POT technique).

The objective of this study is to compare the configuration achieved with POT/KISS/POT (PKP) and POT/SIDE/POT (PSP), using the "cutting edge" high-resolution intracoronary imaging modality (Optical Coherence Tomography, OCT).

A preclinical phase of the study (CRABBS-VHL) was performed in isolated porcine hearts comparing the two common side-branch (SB) optimization techniques after stent implantation in the main vessel (MV): proximal optimization technique (POT) + kissing balloon inflation + final POT (PKP arm) and POT + isolated balloon inflation + final POT (PSP arm).

A total of 30 PCIs were successfully performed. Baseline characteristics of treated bifurcations were similar between the two study arms. Minimum stent expansion at the distal main vessel (MV) segment was significantly lower with PSP as compared with PKP as assessed by both OCT and Micro-CT . Other significant findings included: higher stent eccentricity index at proximal MV with PSP, higher SB scaffolding length and lower malapposition (at bifurcation core and distal MV) with PKP.

These data need to be confirmed by further randomized studies in humans.

Clinical inclusion criteria:

• Subject has coronary artery disease involving a bifurcation with evidence of myocardial ischemia, including patient with chronic coronary syndromes, unstable angina, or non-ST elevation-acute coronary syndromes (NSTE-ACS) hemodynamically stable.
• Subject is suitable to be treated by PCI according to operator's judgement or heart team decision.
• PCI planning includes provisional stenting and image guidance by OCT use.
• Patient is aged ≥ 18 years.
• Patient can provide written informed consent

Angiographic inclusion criteria:

- De novo coronary lesion involving the left main bifurcation, or a bifurcation lesion not located in the left main with large branches (distal MV reference diameter ≥ 3.5 mm and SB reference diameter ≥ 2.75 mm on visual estimation)

Clinical exclusion criteria:

• Acute coronary syndromes with ST-elevation (STE-ACS)
• Cardiogenic shock
• LVEF ≤ 30%
• Pregnancy
• Known severe thrombocytopaenia (platelet count < 50,000/mm3)
• eGFR ≤ 30 mL/min/m2 (Cockcroft-Gault)
• Contraindications to antiplatelet drugs/anticoagulant drugs
• Significant allergic reactions for contrast agent
• Women with pregnancy potential.

Angiographic exclusion criteria:

• Target chronic total occlusion
• Planned 2 stent-strategy
• Target bifurcation lesion has a previously implanted stent
• Target graft lesions
• Medina 0.0.1 target lesions