van Walraven et al developed a simple prediction rule for determining when a patient with non-valvular atrial fibrillation can receive aspirin for stroke prophylaxis, irrespective of the patient's age. These patients do not require therapy with oral anticoagulants. The authors are from multiple university hospitals in North America and Europe.


Exclusions used in studies:

(1) recent stroke, TIA, acute coronary syndrome or cardiac revascularization

(2) contraindications for oral anticoagulation or aspirin therapy (pregnancy, alcoholism, renal failure, hepatic failure, thrombocytopenia, bleeding disorder; I assume aspirin sensitivity would also apply).

(3) other indication for oral anticoagulation


Requirements for stroke prophylaxis with aspirin (exclusions):

(1) no previous history of TIA or stroke

(2) not being treated for hypertension

(3) systolic blood pressure < 140 mm Hg

(4) no angina

(5) no history of previous myocardial infarction

(6) does not have diabetes mellitus



• Patients meeting these requirements would be classed as low risk for stroke.

• Doses of heparin used for prophylaxis ranged from 75 to 325 mg per day.

• A person unable to tolerate aspirin are to be evaluated by one of the other risk-benefit schemes for patients with non-valvular atrial fibrillation. I would imagine that a tolerated aspirin alternative might give similar results, since the primary feature of the rule is to identify patients at low risk for stroke.


Patients who meet these requirements and who are treated with aspirin have stroke rates comparable to age-matched controls in the community, with no additional benefit from oral anticoagulant therapy.


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