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I read with great interest the paper by Kim et al. (1), in which the investigators found that, compared with warfarin, direct oral anticoagulants (DOACs) were associated with a significantly reduced risk of thromboembolic events in patients with mitral stenosis.
Warfarin remains the only oral anticoagulant for patients with atrial fibrillation (AF) and moderate to severe mitral stenosis on the basis of a potentially higher risk and different mechanism of thrombosis. However, mitral stenosis and nonvalvular AF have similar mechanisms of thrombosis, such as the low flow or stasis of the blood in the left atrial appendage. Mitral stenosis also has significant hemodynamic changes with a higher prevalence of thrombus location within the body of the left atrium. Therefore, it is reasonable to expect that DOAC use in mitral stenosis may be as effective as in nonvalvular AF.
This study conducted by Kim et al. (1) in patients with off-label DOACs use provided a potential answer to this question, which suggested that DOACs are promising. I sometimes try off-label use of DOACs in patients with mitral stenosis, especially in cases of severe adverse events with warfarin use in daily practice. Although this is not a randomized trial, it is meaningful for clinical practice. It is well known that rheumatic mitral stenosis is still prevalent in developing countries (e.g., in Asia), and that a low rate of anticoagulant therapy, a relatively high bleeding risk, and inconvenience with warfarin are the main issues that need to be resolved urgently. Therefore, “DOACs may be the special gift that God gives to the Asians” (2).
The main limitations of the study were its retrospective design and that the quantitative data for mitral stenosis were unavailable, making the subgroup analysis impossible. Moreover, international normalized ratio data, especially the therapeutic range that reflects the quality of anticoagulation with warfarin, were also unavailable. However, because of the poor quality of anticoagulation status in most Asian countries, DOACs may be an alternative treatment.
A randomized trial has been conducted to evaluate the superiority of DOACs against warfarin in patients with mitral stenosis (3); it is anticipated that AF accompanying mitral stenosis would be treated by DOACs.
Please note: Dr. Huang has reported that he has no relationships relevant to the contents of this paper to disclose.
- 2019 American College of Cardiology Foundation
- Kim J.Y.,
- Kim S.H.,
- Myong J.P.,
- et al.
- Bang O.Y.,
- Hong K.S.,
- Heo J.H.,
- et al.
- De Caterina R.,
- John C.A.