Author + information
- Zachary L. Steinberg, MD∗ ( and )
- Eric V. Krieger, MD
- ↵∗Division of Cardiology, Department of Medicine, University of Washington School of Medicine, 1959 NE Pacific Street, Box 356422, Suite AA522, Seattle, Washington 98195-6422
Drs. Godin and Tanguay raise an interesting question: Might direct oral anticoagulants (DOACs) provide superior anticoagulation for pregnant women with mechanical heart valves (MHVs) compared with low-molecular-weight-heparin and avoid the teratogenicity of vitamin K antagonists?
Drs. Godin and Tanguay acknowledge that the limited data available should give us pause for embracing this anticoagulation strategy at this point. Although some in vitro and animal studies suggest comparable effectiveness of DOACs, warfarin, and low-molecular-weight-heparin (1–3), the only randomized controlled study to date in patients with MHVs reported a significant increase in thromboembolic events with the use of dabigatran over warfarin (4). Despite previous research showing a lower incidence of bleeding in patients with atrial fibrillation treated with dabigatran (5), dabigatran was associated with significantly more bleeding in patients with MHVs (4). The fetal effects of DOACs are also controversial, and their fetal safety over warfarin during the second and third trimesters has not been established.
Pregnancy is a time of markedly increased risk of valve thrombosis, regardless of the anticoagulation strategy used. For this reason, it is even more critical that the efficacy of DOACs for MHVs be established in the general population before we embark on human trials of DOACs for MHVs in pregnancy. As Drs. Godin and Tanguay point out, this idea is intriguing and deserving of further investigation. However, we believe additional preclinical work is needed before recommending DOACs for pregnant women with MHVs, even within the context of research.
Please note: Both authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2017 American College of Cardiology Foundation