KISS study is an investigator-initiated, multi-centre, prospective, randomized (1:1), parallel, two-arm, non-inferiority trial aiming to compare two bifurcation PCI procedures for Side Branch protection

In the treatment of bifurcation lesion, the role of side branch intervention for improving the safety of Percutaneous Coronary Intervention (PCI), when MB is treated according to the Murray law with a Proximal Optimization Technique (POT), remains unclear.

The KISS study will evaluate the non-inferiority of no side branch intervention versus side branch ballooning, in the setting of single stenting with systematic proximal optimization technique.

Inclusion Criteria:

1. Coronary artery disease requiring revascularization that is amenable to percutaneous coronary intervention (PCI)
2. Any de novo Medina type bifurcation lesion with >70% lesion in the main vessel by visual assessment except Medina 0,0,1 if the planned strategy does not include a main branch stenting
3. Side branch diameter compatible with a PCI with stent implantation (≥ 2.25mm)
4. Side branch requiring a protection wire according to operator evaluation
5. Anatomy compatible with a proximal optimization technique
6. Post main branch treatment (stenting then POT): Absence of side branch occlusion Or low flow associated with ongoing ischemia (either chest pain or ST changes)
7. Male or female patient >18 years old

Exclusion Criteria:

1. Acute myocardial infarction with ongoing ST-elevation
2. Cardiogenic shock
3. Requirement for ongoing hemodialysis
4. Life-expectancy limited to <12 months due to co-morbid condition
5. Lesion involves the left main coronary artery
6. Lesion requiring a double stenting
7. Plan to treat >1 other coronary vessel at the time of the index procedure
8. Two lesions treated in the same session: unsuccessful PCI on the single non bifurcation lesion in a non-target vessel before the treatment of the target lesion.
9. Chronic total occlusion of any target vessel
10. Left ventricular ejection fraction <20%
11. Side branch TIMI Flow <3
12. Pre-dilatation of the Side Branch during the procedure prior to randomization
13. Known allergy to Aspirin
14. Known allergy to Clopidorel and Prasugrel and Ticagrelor
15. Known allergy to stent drug elutant
16. Known allergy to any other component of Onyx Resolute stent
17. Ongoing participation in another investigational device or drug study
18. Inability to provide informed consent
19. Patients under judicial protection, tutorship or curatorship
20. Pregnant and breast-feeding women or intention to become pregnant prior to completion of all follow-up procedures