Decision Making Non-culprit LM lesion after PCI of RCA in an ACS - Low Syntax Score: Syntax Score I: 13 and Syntax score 2020: 17,1; with low risk of bleeding: PRECISE-DAPT: 14 - Heart Team determined: LM should be treated by PCI - It was predetermine: PCI guided by IVUS - Initial planning: Implant a DES in LM > DA; provisional technique. Clinical Evolution after PCI - PCI was sucesful without any complications - Patient was discharge after 24 hours in optimal conditions Conclusions - STEMI is associated with multivessel disease in aprox. 40% of cases - Non-culprit lesion of LM is always a challenge - PCI guided by IVUS was useful to maintain the initial plan (provisional technique) and determine the non important lesion in LCX ostium - IVUS after PCI help in the optimization of the LM PCI - POT is one of the most important steps in any bifurcation PCI - If possible every LM PCI should be guided by IVUS.