A Case of Ticagrelor Resistance.

UNLABELLED: Ticagrelor is a directly acting cyclopentyltriazolo-pyrimidine which does not require conversion into an active metabolite. It inhibits the P2Y12 receptors on platelets reversibly. Unlike clopidogrel and prasugrel, resistance to ticagrelor is rarely reported. Various mechanisms have been proposed for this resistance. The case of a 62-year-old man with diabetes who had undergone index percutaneous coronary intervention (PCI) 22 days previously is described. The patient presented to us with stent thrombosis. His primary PCI was successfully carried out with a drug-eluting stent. He showed resistance to ticagrelor on thromboelastography platelet mapping. He responded well to prasugrel (another P2Y12 inhibitor) in combination with aspirin.

LEARNING POINTS: Ticagrelor is a pro-drug and directly inhibits P2Y12 receptors.This makes ticagrelor less susceptible to drug-drug interactions or pharmacogenetic influences.Thromboelastography platelet mapping measures the physical properties of clot formation and can reveals platelet resistance to various P2Y12 inhibitors, including ticagrelor.