Warfarin is the standard anticoagulation therapy for valvular atrial fibrillation (AF); however, new oral anticoagulants have emerged as an alternative. We compared the efficacy and safety of dabigatran with conventional treatment in AF associated with left-sided valvular heart disease (VHD), including mitral stenosis (MS). Patients with AF and left-sided VHD were randomly assigned to receive dabigatran or conventional treatment. The primary end point was the occurrence of clinical stroke or a new brain lesion (silent brain infarct and microbleed) on 1-year follow-up brain magnetic resonance imaging. Patients in the dabigatran group were switched from warfarin (n = 52), antiplatelets alone (n = 5), or no therapy (n = 2) to dabigatran. In the conventional group, 53 used warfarin (including 42 MS patients), and 7 used antiplatelets. No death or clinical stroke event occurred in either group during follow-up. Silent brain infarct and microbleed occurred in 20 and 2 patients in the dabigatran group and 20 and 4 patients in the conventional treatment group. The incidence rate of the primary end point did not significantly differ between groups (34% vs 40%, relative risk 0.87, 95% confidence interval 0.59 to 1.29, p = 0.491). The primary end point rate was similar between groups in 82 patients (40 in the dabigatran group and 42 in the conventional group) with MS (32% vs 34%, relative risk 0.93, 95% confidence interval: 0.57 to 1.50, p = 0.759). In conclusion, primary end point rates after treatment with dabigatran were similar to conventional treatment in patients with significant VHD and AF. New oral anticoagulants could be a reasonable alternative to warfarin in patients with AF and VHD, which should be confirmed in future large-scale studies.
This study has several important limitations such as sample size, inclusion criteria, and heterogeneity of the sample that make it of limited clinical value.
Interesting article that addresses an important and relevant question. Data quality may be questionable, however, as the sample size was too small and the study was very underpowered and unequally distributed. The control group had significantly higher risk and quite poor management. Definitely more data are needed before this study`s message can be used in practice.
Patients with valvular atrial fibrillation represent a minority of afib cases managed by generalists, so the relevance of this article is likely lacking for many primary care physicians. That said, this article is relevant for some management decisions and addresses an evidence gap in patients with native valvular afib. Mechanistic explanations, clinical experience, and antecedent experimentation with DOACs for non-valvular atrial fibrillation lend credence to the hypothesis that dabigatran might carry superior efficacy and safety compared with conventional therapy (warfarin). This trial attempts to sort this hypothesis out empirically, however, its methodologic flaws limit meaningful interpretation and translation. Although a negative trial, the study was not powered to detect smaller but clinically meaningful differences. Furthermore, surrogates were used without sufficient justification. Larger trials exclusively using clinical endpoints are needed.
Very important to include. I see the risk for falls in the older age group and resultant death from ICD SDH fracture and resultant decline (as a Medical Examiner that must certify accidental deaths). I feel strongly that we need to know the benefits of all oral anticoagulants vs the risks, especially in the aging population.
I would view this as interesting but preliminary. When most of us say "valvular afib", we often mean afib due to severe MS, and this study did not have many people with this as the underlying problem. Probably warrants a bigger and more focused study.