The usual regimen after a DES (drug eluding stent) is one year on plavix to help prevent blood clots with aspirin and after one year continue with just aspirin (87 mg).
However, pooled data from randomized trials show that coumadin reduces the risk of stroke from 4.5 percent to 1.4 percent per year in patients with nonvalvular atrial fibrillation and no history of stroke or transient ischemic attack.
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).
Your doctor should have your health history and base medication on your vulnerability for a stroke and clots.
Hope this helps, and if not you are welcome to a follow-up response. Thanks for sharing your concern.