The aim of POLBOS I (POLish Bifurcation Optimal Stenting) study was to compare two intervention strategies for bifurcation treatment: provisional T-stenting (PTS) with any regular drug-eluting stent (rDES), the best treatment strategy at the moment, with stenting of bifurcation lesions with dedicated bifurcation paclitaxel-eluting stent BiOSS Expert® (Balton, PL).