Antiplatelet treatment in acute coronary syndromes

Platelets play a major role in the development of acute coronary syndromes (ACS) and thromboembolic complications during and after percutaneous coronary interventions (PCI). Because of the widespread usage of platelet inhibitor agents in the treatment of patients with a broad spectrum of ACS it appears to be important to review the data concerning the usefulness and limitations of these agents. Moreover, the phenomenon of resistance to antiplatelet agents appears nowadays as substantial problem and is a subject of extensive experimental and clinical research. Acetylsalsalicylic acid, thienopyridines (ticlopidine, clopidogrel) and IIb/ IIIa glycoprotein platelet receptor blockers (abciximab, eptifibatide and tirofiban) are currently used in patients with ACS. Every drug (or drug family) inhibits specific platelet aggregation pathway: thromboxane A2-(acetylsalsalicylic acid) or ADP-(thienopyridines) dependent or inhibits platelet fibirinogen receptor (GBIIb/IIIa receptor blockers). Acetylsalsalicylic acid and clopidogrel are recommended by European Society of Cardiology for patients with ACS undergoing PCI as well as for a long-term therapy; IIb/IIIa glycoprotein platelet receptor blockers before and during PCI. This was unanimously proved, that platelet inhibitor agents reduce the rate of major adverse cardiac events (MACE) in patients suffering from ACS. However, the major limitation of these drugs is the resistance phenomenon, concerning in principle all platelet inhibitor agents and related to stent thrombosis with it’s ominous 45% mortality rate. The standardized, quick and reliable tests are urgently needed to identify patients resistant to a given antiplatelet agent, which could translate into further reduction of MACE. (Folia Cardiol. 2005; 12: 585–593) platelets, acute coronary syndromes, percutaneous coronary intervention, platelet inhibitor agents, resistance