Effect of antithrombotic therapy in patients with mitral stenosis and atrial fibrillation: a sub-analysis of NASPEAF randomized trial

Abstract

The randomized NASPEAF study included non-valvular with prior embolism and mitral stenosis patients in the same group. This is a sub-study to specially focus on the antithrombotic therapy in mitral stenosis. We analysed 311 patients with mitral stenosis, compared with 175 non-valvular atrial fibrillation patients with prior embolism, stratified by a history of previous embolism and assigned to anticoagulant therapy [target international normalized ratio (INR) = 2.0-3.0] or combined antiplatelet plus moderate intensity anticoagulant therapy. Median follow-up was 2.9 years. Outcomes were fatal and non-fatal embolism, stroke and myocardial infarction, sudden death, and death from bleeding. Combined therapy in mitral stenosis patients, compared with anticoagulant alone therapy, reduced the risk of vascular events by 58.3%. During equal therapy, the outcome annual rates were essentially the same in non-valvular and valvular patients [hazard ratio 0.90 (95% confidence interval 0.37-2.16), P = 0.81]. During anticoagulant alone therapy, the annual event rate in mitral stenosis patients without prior embolism was low (2.5%) and it was very high in patients with prior embolism (6.6%). Combined therapy was effective in mitral stenosis patients. Prior embolism patients are not efficiently protected with anticoagulant alone therapy for an INR of 2.0-3.0.