For the millions of adults living with aortic valve stenosis, the choice of blood-thinning therapy after a transcatheter valve replacement has long been debated without a clear, high-quality answer. This randomized trial directly challenges the current default of aspirin monotherapy and may reshape post-TAVI antithrombotic protocols for a generation of younger, healthier patients increasingly receiving the procedure.
The ACASA-TAVI trial enrolled 360 patients aged 65 to 80 at three Norwegian centers — institutions collectively managing the national majority of TAVI volume — and randomized them equally to 12 months of either a factor Xa inhibitor NOAC or acetylsalicylic acid (ASA) alone. The primary efficacy endpoint was leaflet thrombosis detected via hypoattenuated leaflet thickening (HALT) on blinded 4D cardiac CT at one year — a subclinical marker increasingly linked to accelerated valve structural deterioration. The primary safety endpoint was a composite of VARC-3 bleeding events, offering a paired lens on both benefit and harm. While the full numerical results remain truncated in the excerpt, the randomized, blinded-endpoint design positions this as one of the most methodologically rigorous head-to-head comparisons yet conducted in this space.
Contextually, this trial arrives as prior observational and registry data have suggested aspirin alone may be insufficient to prevent subclinical leaflet thrombosis, while earlier NOAC trials like GALILEO raised safety concerns about bleeding excess. ACASA-TAVI's monotherapy-versus-monotherapy design sidesteps the dual-therapy confound that plagued earlier research. The population — relatively younger TAVI recipients at lower surgical risk — is exactly the cohort where long-term valve durability matters most. Key limitations include the single-country setting, which may limit generalizability across valve types and operator volumes, and the 12-month endpoint, which may not capture late thrombotic or bleeding events. If NOAC monotherapy proves superior on HALT without a bleeding penalty, this trial carries genuine paradigm-shifting potential for post-TAVI care guidelines.