Introduction: Percutaneous treatment of bifurcation lesion is a complex procedure. After main vessel stent implantation, the side branch became jailed and the carina can be displaced resulting in complete occlusion of this vessel. Re-wiring the side branch in this conditions may result difficult and some times impossible. There is no agreement regarding the need of side branch pre-dilation (before main vessel stent implantation) to reduce these complications. Researchers from European Bifurcation Club have proposed no to pre-dilate the side branch to avoid vessel dissection and difficulties in rewiring the true lumen of the vessel. On the contrary, our group has a good experience in the treatment of bifurcation lesions treated with side branch pre-dilation.