A piece of that clot can break off and form an embolus, which may travel through the circulation to the brain, making a stroke more likely. In a nationwide sample researchers Randall S. Stafford, M.D., Ph.D., and Daniel E. Singer, M.D., found less than 40 percent of patients with atrial fibrillation were taking warfarin. Stafford and Singer are at Massachusetts General Hospital, Boston. Because of the importance of treating diagnosed atrial fibrillation as a way to possibly prevent stroke, the American Heart Association recommends aggressive treatment of this heart arrhythmia. Aspirin and warfarin, the currently used medications, can have a major beneficial effect on public health in the United States.
Physicians differ on the choice of drugs to prevent embolic stroke, stroke caused by an embolus.
It is clear that warfarin is more effective against this type of stroke than aspirin. However, warfarin has side effects, especially in older patients. Warfarin in well-regulated doses that lead to a moderate interference with clotting is effective and appears safe in many patients. Patients at high risk for stroke should probably be treated with warfarin rather than aspirin unless there are contraindications, such as potential bleeding problems or ulcer. Patients over 75 should be followed especially carefully.