Systemic embolic events (SEEs) complicate atrial fibrillation but get less attention than ischemic stroke (IS). Non-vitamin K antagonist oral anticoagulants (non-VKAs) prevent IS. In a recent study published in the Circulation, the researchers tested their effect on SEE using patient data from key trials.

This individual patient meta-analysis pooled data from 4 randomized trials (2005-2010) comparing non-VKAs to warfarin in AF. Among 71,683 patients, they tracked 188 SEE cases (26 with concurrent IS). Analyses compared SEE incidence, features, management, outcomes to IS patients. Cox models assessed non-VKA effects over median 25.2 months follow-up.

SEE annualized rate was 0.13% per patient-year (188 events) vs 1.25% for IS (1797 events). SEE patients (n=171 first events) averaged age 75 years, 49.7% female, CHA2DS2-VASc 4.7±1.5. Versus IS, SEE linked to more peripheral artery disease (16.5% vs 5.4%, p<0.001), prior MI (24% vs 17%, p=0.02), warfarin exposure (57% vs 46%, p=0.007), worse kidneys (CrCl 58 vs 62 mL/min, p=0.02), nonparoxysmal AF (86% vs 80%, p=0.047). Interventions hit 31%. Non-VKAs reduced SEE 29% vs warfarin (HR 0.71, 95% CI 0.51-0.99, p=0.04). 30-day SEE mortality matched IS (18% vs 17%); long-term nearly 3-fold higher vs no events (HR 2.85, 95% CI 2.11-3.85).

In this large trial cohort, non-VKAs associated with lower SEE risk versus warfarin. SEE patients showed distinct profiles and high morbidity. Findings highlight broader embolic protection needs.