Warfarin not necessarily the go-to therapy, Korean study finds
Patients with mitral stenosis and atrial fibrillation (Afib) did well on direct oral anticoagulants (DOACs) for thromboembolic event prevention, retrospective data indicated.
Individuals with both conditions who were using DOACs off-label had fewer ischemic strokes and systemic embolisms compared to a matched cohort of peers getting standard warfarin treatment (2.22% per year vs 4.19% per year, adjusted HR 0.28, 95% CI 0.18-0.45).
They also had fewer intracranial hemorrhages over a mean 27 months of follow-up (0.49% vs 0.93%, adjusted HR 0.53, 95% CI 0.22-1.26), according to Sung-Hwan Kim, MD, of Seoul St. Mary's Hospital, The Catholic University of Korea, and colleagues.
Rates of all-cause death favored DOAC users as well (3.45% per year vs 8.08% per year, adjusted HR 0.41, 95% CI 0.30-0.56), they wrote in the Journal of the American College of Cardiology.
The investigators concluded that DOAC use "appears reasonable" in patients with mitral stenosis with Afib -- a group that has been excluded from the large DOAC trials and recommended oral anticoagulation therapy with a vitamin K antagonist instead, they noted, because mitral stenosis itself is a high-risk factor for thromboembolism.
The next step would be to see how DOAC therapy does in a randomized trial, the authors said.
Such a trial would have to include patients from all around the world given the evolving demographics of rheumatic heart disease and the limited availability of DOACs in certain areas, said Robert Giugliano, MD, and Patrick O'Gara, MD, both of Brigham and Women's Hospital in Boston.
"Nevertheless, we agree with the authors and others that the time has come to answer this question with an adequately powered randomized clinical trial with significant implications for the health of vulnerable populations," they wrote in an accompanying editorial.
Kim's group based the study on 2,230 patients included in Korea's Health Insurance Review and Assessment Service database (excluding those who had a prior mitral valve surgery). After propensity matching, the investigators ended up with similar baseline characteristics between DOAC and warfarin groups.
Study participants were age 69.7 on average and 30.6% men. The mean CHA2DS2-VASc score was 5.2. DOACs used were rivaroxaban (Xarelto; 42.3%), dabigatran (Pradaxa; 32.9%), apixaban (Eliquis; 17.2%), and edoxaban (Savaysa; 7.5%).
"Given the paucity of information regarding the use of DOACs in patients with mitral stenosis, these observational data are welcome and should be viewed as hypothesis-generating," according to Giugliano and O'Gara.
"Only 7.5% of the patients with mitral stenosis and Afib who were identified were included in this analysis, with more than one-third excluded because they received no anticoagulation. This suggests that many patients at higher risk of bleeding were excluded," they noted.
Ultimately, the magnitude of benefits reported in the study "appear overly optimistic" and may be influenced by residual confounding, the duo cautioned. "However, the absence of negative signals in this observational report do warrant further confirmation."
Kim and co-authors disclosed funding from the Catholic Medical Center Research Foundation.
Giugliano disclosed institutional participation in clinical trials from Daiichi-Sankyo and Merck, and relevant relationships with Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi-Sankyo, Janssen, Merck, Portola, and Pfizer.
O'Gara disclosed relevant relationships with Medtronic, Edwards Lifesciences, and the National Heart, Lung, and Blood Institute.
Read the original article on Medpage Today: DOACs Promising for Afib Patients With Mitral Stenosis