Angiographic Acute Stent Thrombosis occur in 0.5%-2% of procedures.OCT-PCI or Optimized PCI represents a new approach particularly indicated in complex high thrombotic risk lesions, in patients at high bleeding risk with need for short DAPT and in the treatment of vulnerable plaques. Post-stent OCT thrombus finding was defined in previous studies as mass with diameter ≥250μm attached to the stent struts, was present until 40% of cases and is associated with definite angiographic thrombosis. Outcome of OCT thrombus is generally favorable although in about 25% there may be a progression. Case 1: 75-y smoker female with hypertension and atrial fibrillation on NOAC therapy presented in ICU with NSTEMI. At angiography: 75% stenosis focal plaque at proximal circumflex (Fig1A). At OCT vulnerable plaque: ulcerated with intimal flap < 90°, thin fibrous cap 20 µm, MLA 2.17mm² and AS 63%, intimal micro-calcifications and cholesterol crystals (Fig1C). We implanted DES with post-dilatation. Treatment was Cangrelor, heparin 100 IU/kg and ASA 250 mg ev. OCT showed acute 660 µm thrombosis of the stent body although there was perfect angiographic result (Fig1D+B). Further multiple balloon dilatation of the stent was carried out with thrombosis persistence on OCT control (Fig1E) and new appearance of multiple thromboses adhering to the intravascular side stent struts (Fig1F-G). Switch from Cangrelor to Tirofiban was done. Patient's clinical course was uneventful with discharge after six days on triple antithrombotic therapy with low-dose NOAC, ASA and clopidogrel.Case 2: 63-y smoker man arrived in cath lab for anterior STEMI. He had already taken ASA 300 mg ev and Ticagrelor 180 mg oral bolus about 60 minutes earlier in the ambulance. In Cath Lab was done heparin 100 IU/kg. P-PCI was performed for acute sub-occlusion (Fig2A) of the ostial DA treated by pre-dilation, DES implantation on Left Main-DA and multiple post-dilations according to the POT technique. OCT control showing extensive stent malapposition (860 µm) with evidence of multiple thromboses adhering to the stent struts on Left Main (diameter 410 µm) although there was perfect angiographic result (Fig2B-E). Procedure was optimized by adequate post-dilatation of the LM and administration of Abciximab. Patient's clinical course was uneventful with discharge after five days on ASA and Ticagrelor.Conclusions: Post-stent OCT thrombus may guide the choice of use of Glicoprotein IIb/IIIA Inhibitors in Cath Lab.