Aspirin or coumadin are for clots, (Antithrombotic and Thrombolytic Therapy), the American College of Chest Physicians (ACCP) recommended coumadin for atrial
fibrillation patients at high risk of
stroke, aspirin for patients at low risk of
stroke,
and either drug of patients with an intermediate risk. The ACCP defines a low-risk patient as younger than 65 years with no predisposing risk factors (e.g., previous stroke, TIA, embolism, heart failure, hypertension, diabetes).