Antithrombotic Therapy for Prevention of Various Thrombotic Diseases

The majority of sudden onset serious diseases, such as acute myocardial infarction, ischemic stroke, and pulmonary embolism, are thrombotic diseases. Antithrombotic therapy in general has a potential to reduce the risk of thrombotic diseases, though it increases the risk of serious bleeding events. Of the various antithrombotic agents currently available, the antiplatelet agent aspirin and the anticoagulant agent warfarin have the most robust clinical evidence. Aspirin reduces the risk of cardiovascular (CV) death, recurrence of myocardial infarction and ischemic stroke by up to 25%. Aspirin is an established standard of care for patients at risk of atherothrombotic events including myocardial infarction and ischemic stroke. In addition to aspirin, there is clinical evidence for antiplatelet drugs targeting platelet P2Y(12) ADP receptors as represented by clopidogrel. Those agents are commonly used in patients with acute coronary syndrome (ACS) and those patients undergo coronary intervention in addition to aspirin. Several newer-generation anti-P2Y(12) agents were developed mostly for the prevention of CV events in patients with ACS. After 50 years of clinical experience with anticoagulant drugs, warfarin became the standard of care in various disease states, including following heart valve replacement, venous thrombosis, stroke prevention in patients with atrial fibrillation, etc. New-generation oral anticoagulants are now available for limited indications. Those new agents are specific inhibitors of thrombin or Xa. Compared with warfarin targeting PT-INR 2-3, those new-generation direct oral anticoagulants are shown not to be inferior to warfarin for reduction of stroke in patients with atrial fibrillation. Efficacy and safety of those agents are being tested in clinical trials for various disease states, but not established yet. Each drug has specific characteristics suitable for specific disease states. It is fortunate for both physicians and patients to have a variety of drug choice. More clinical evidence is required for selection of suitable patients for new-generation antithrombotic agents. (C) 2013 Wiley Periodicals, Inc.