PGI2 stands for Prostacyclin in medicine. Prostacyclin is also known as prostaglandin I2, cycloprostenol, and epoprostenol. Prostacyclin is a member of the lipid, arachidonoid family, with a secondary five-membered ring in the molecule, and its precursor is arachidonic acid or other eicosanoid unsaturated fatty acid. Prostacyclins inhibit platelet-mediated coagulation and have a strong vasodilatory effect, so that during coagulation, prostacyclin production in the damaged vascular endothelium is reduced, favoring platelet aggregation.