ENBALV: Edoxaban or warfarin as anticoagulant after bioprosthetic valve replacement?

The ENBALV study explored the use of direct anticoagulants (DOACs) in patients who receive early anticoagulant therapy after bioprosthetic valve surgery. However, the evidence appears to be inconclusive on whether edoxaban is a potential treatment for the population.

“The incidence of embolic events is high early after bioprosthetic valve replacement,” said Dr Chisato Izumi (National Cerebral and Cardiovascular Center, Japan) [1]. “This may be due to thrombus formation on prosthetic valves, perioperative atrial fibrillation, or cardiac dysfunction.” Dr Izumi explained that the administration of DOACs at the time of discharge after bioprosthetic valve replacement has been increasing in clinical practice despite this being an off-label strategy.

The phase 3, investigator-initiated ENBALV trial compared the DOAC edoxaban with the vitamin K agonist warfarin in patients who underwent bioprosthetic valve replacement (n=410). Randomisation occurred in a 1:1 fashion, and participants received their allocated therapy for 12 weeks. The primary efficacy outcome was a composite of stroke or systemic embolism, and the key safety endpoint was major bleeding.

Only 1 event and 3 events occurred in the edoxaban arm and warfarin arm, respectively, not displaying a significant difference between the study drugs regarding the primary endpoint (0.5% vs 1.5%; risk difference -1.03; 95% CI -4.34 to 1.95). There were numerically, but not significantly, more major bleeding events in the edoxaban arm than in the warfarin arm (4.1% vs 1.0%; risk difference 3.07; 95% CI -0.67 to 7.27).

Discussant Prof. Philippe Steg (Bichat Hospital, France) commented that the event numbers were too low to conclude that edoxaban provided comparable efficacy with warfarin. Moreover, “warfarin treatment was poorly controlled in the trial. Bleeding appeared to be more common in the edoxaban arm.” He concluded that more work needs to be done to establish DOACs as a viable treatment option early after surgery in patients who undergo bioprosthetic valve replacement procedures.

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   1. Izumi C, et al. Efficacy and safety of edoxaban in anticoagulant therapy after surgical bioprosthetic valve replacement. LBS.04, AHA Scientific Sessions 2024, 16–18 November, Chicago, USA.

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Posted on 3 February 2025