[Risk factors for thromboembolism in patients with atrial fibrillation during treatment with aspirin: a multicenter, cooperative retrospective study. Research Group for Antiarrhythmic Drug Therapy].
Warfarin is effective in preventing thromboembolism in patients with atrial fibrillation, but aspirin is frequently used as an alternative treatment. A multicenter, retrospective study was undertaken to identify patients at risk for thromboembolism during treatment with aspirin. The study group consisted of 470 patients (318 males, 152 females, mean age 59.9 +/- 11.8 years at initial examination) with atrial fibrillation who were treated with aspirin. Thirty-seven percent of patients had paroxysmal atrial fibrillation and 65% of patients received aspirin at a daily dose of 81 mg. Thromboembolism occurred in 31 patients (6.6%) during the follow-up period, resulting in cerebral infarction in 19 patients, transient ischemic attack in 7, and embolism of peripheral arteries in 5. Patients with thromboembolism had lower prevalence of New York Heart Association (NYHA) functional class I (52% vs 72%, p < 0.02) and paroxysmal atrial fibrillation (23% vs 38%, p = 0.085) compared with patients without thromboembolism. Multivariate analysis with the Cox proportional hazard model determined age (> or = 65 years, relative risk 2.29, p = 0.032) as an independent risk factor. NYHA functional class (> or = class II) tended to indicate an increased risk of thromboembolic events (relative risk 1.90, p = 0.076). These results suggest that aspirin has limited efficacy for prevention of thromboembolism in patients with atrial fibrillation who are old (> or = 65 years) or have symptomatic heart failure.
D000367:Age Factors; D000704:Analysis of Variance; D001241:Aspirin / Q000008:administration & dosage / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D005260:Female; D006331:Heart Diseases / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D012189:Retrospective Studies; D012307:Risk Factors; D013923:Thromboembolism / Q000517:prevention & control*
D010975:Platelet Aggregation Inhibitors; D001241:Aspirin