Acute Stent Thrombosis During Glycoprotein IIb/IIIa Inhibitor Infusion.

Acute stent thrombosis (ST) represents an infrequent but critical complication occurring within 24 h post-percutaneous coronary intervention (PCI). It is most associated with inadequate antiplatelet therapy, stent underexpansion, or malapposition. We report the case of a patient with acute coronary syndrome treated with PCI under optical coherence tomography guidance, who developed recurrent chest pain and ST-segment elevation 7 h after the initial procedure. Urgent coronary angiography revealed acute ST within the newly implanted stent, despite intravascular imaging-guided PCI and optimal antiplatelet therapy. The most probable cause was an untreated, hemodynamically significant stenosis at the crux of the right coronary artery, distal to the implanted stent. This critical downstream lesion impaired coronary flow, leading to stasis within the long proximal stent and creating a highly prothrombotic environment, ultimately overwhelming even potent glycoprotein IIb/IIIa inhibition. Post-dilatation of the distal coronary stenosis resulted in improved coronary flow and complete resolution of symptoms, with no recurrence observed during the remainder of the hospitalization. Optimization of PCI using intracoronary imaging and adequate antiplatelet therapy is essential for reducing the incidence of acute ST. However, untreated residual stenoses that significantly impair distal flow may also play a pivotal role in ST formation and should be addressed during the primary procedure.