Aspirin and Antiplatelet Therapy

This chapter provides cardiologists and cardiology/echocardiography trainees with case-based questions regarding aspirin and antiplatelet therapy. It includes clear explanations and discussions for every question. Reviewing these questions and answers helps trainees to successfully prepare for the ABIM Cardiology Board Review examination. Ticagrelor reversibly binds to the P2Y12 receptors on the platelet surface, and thus recovery of platelet function is likely dependent on serum concentrations of ticagrelor. Aspirin irreversibly inhibits the COX-1 and COX-2 enzymes, and clopidogrel and prasugrel irreversibly bind to the P2Y12 receptors. Thus, aspirin, clopidogrel, and prasugrel inhibit coagulation for the lifespan of the platelet. Warfarin inhibits the vitamin K-dependent synthesis of factors II, VII, IX, X and proteins C and S. Because the half-life of factor II may be as long as 48-72 hours, it is recommended to overlap initial warfarin therapy with a faster-acting parenteral agent.