Antithrombotic and thrombolytic therapy in acute cardiac care

The acute coronary syndromes (including unstable angina and non-ST-elevatio n myocardial infarction) and ST-elevation myocardial infarction(17) are rel ated pathogenetically, because each represents a different stage of plaque rupture and thrombosis.(44, 45) These entities involve the coagulation casc ade at different levels and intensities. Hence, antithrombotic therapy play s a major role in the management of acute coronary syndromes. In most patients presenting with acute coronary syndromes, the thrombus is only partially occlusive. Antithrombotic agents maintain vessel patency by preventing the progression of a nonocclusive thrombus to an occlusive throm bus and by inhibiting the generation of new thrombi. In contrast, the infar ct-related artery in most patients with ST-segment elevation is occluded co mpletely by thrombus. Therefore, the first goal in these patients is to ach ieve rapid reperfusion by mechanical dissolution of thrombus or administrat ion of thrombolytic therapy. Second, it is important to maintain patency of the infarct-related artery to prevent recurrent thrombosis leading to reoc clusion and recurrent ischemia. This maintenance is accomplished by anticoa gulant and antiplatelet therapy. Recent multicenter clinical trials have led to the introduction of new anti thrombotic agents in the management of acute coronary syndromes. These incl ude platelet glycoprotein IIb/IIIa (GP IIb/IIIa) receptor inhibitors, low m olecular weight heparins (LMWHs), and direct thrombin inhibitors. These inn ovations promise to improve patient outcomes, but their relatively recent d evelopment raises questions of how best to use the agents in combination wi th traditional antianginal agents, each other, and percutaneous interventio n. Developing strategies of care and critical pathways(7) demand more than administering every drug to every patient.(27) This article reviews the rap id expansion in the antithrombotic therapeutic armamentarium for acute coro nary syndromes in the context of optimal management.