Non-Vitamin K Antagonist Oral Anticoagulants for Thromboembolic Prevention in Patients with Atrial Fibrillation and Concomitant Mitral Stenosis: A Retrospective Observational Study.

Background: Atrial fibrillation (AF) increases the risks of ischemic stroke and systemic embolism, especially in patients with mitral stenosis (MS). Non-vitamin K antagonist oral anticoagulants (NOACs) are effective in preventing AF-related stroke and systemic embolic events. However, patients with AF and concomitant moderate-to-severe MS have been excluded from previous pivotal studies. We aimed to evaluate and compare the efficacy and safety of NOACs with vitamin K antagonists (VKAs) in this patient group.

Methods: This retrospective observational study used data from the Chang Gung Research Database. We enrolled patients with AF and concomitant moderate-to-severe MS between January 2010 and December 2019. Propensity score matching was used to balance covariates between the NOAC and VKA groups. The risks of stroke, systemic embolism, and bleeding events were assessed following treatment.

Results: After PSM, 115 patients with AF and concomitant moderate-to-severe MS were analyzed, of whom 32 were treated with NOACs and 83 with VKAs. There were no significant differences in the composite efficacy outcomes and bleeding risk between the NOAC and VKA groups. However, the all-cause mortality incidence rate was significantly lower in the NOAC group. Cox regression analysis showed that CHA₂DS₂-VASc score, but not mitral valve area, was a significant predictor of the composite efficacy outcomes.

Conclusions: NOACs were as effective as VKAs in preventing stroke and systemic embolic events, with comparable bleeding risks in AF patients with concomitant moderate-to-severe MS. CHA₂DS₂-VASc score was superior to mitral valve area in predicting composite efficacy outcomes.