Anticoagulation Reduces Subclinical Leaflet Thrombosis After TAV

Factor Xa inhibitor monotherapy reduced subclinical leaflet thrombosis after transcatheter aortic valve implantation (TAVI) compared with aspirin and met a prespecified noninferiority criterion for a composite safety endpoint in the randomized ACASA-TAVI trial published in JAMA.

The prospective, open-label, blinded-endpoint trial enrolled 360 adults aged 65 to 80 years at 3 Norwegian centers. Participants were assigned 1:1 to receive 12 months of monotherapy with a factor Xa inhibitor non–vitamin K antagonist oral anticoagulant (NOAC) or acetylsalicylic acid. The protocol permitted clopidogrel for participants who were intolerant to aspirin or had used clopidogrel before enrollment; 11 participants in the control group received clopidogrel.

At 12 months, hypoattenuated leaflet thickening on 4-dimensional cardiac computed tomography occurred in 27 of 167 participants assigned to NOAC therapy and 48 of 168 assigned to aspirin, corresponding to rates of 16.2% and 28.6%, respectively. The risk ratio was 0.55 (95% CI, 0.37–0.82; P=.004).

The primary safety composite of bleeding, thromboembolic events, and all-cause death occurred in 13 participants (7.5%) in the NOAC group and 19 (10.6%) in the aspirin group. The absolute risk difference was −3.3 percentage points (95% CI, −9.5 to 2.8; P<.001 for noninferiority). Clinical thromboembolic events occurred in 7 of 173 participants receiving NOAC therapy and 5 of 175 receiving aspirin.

The unexpectedly low safety-event rate produced a larger relative noninferiority margin than planned, limiting the strength of the safety conclusion. Other limitations included the open-label design and enrollment of only patients aged 65 to 80 years. The trial also was not powered to compare individual major clinical outcomes. The findings indicate that factor Xa inhibitor monotherapy can reduce imaging-detected leaflet thrombosis in selected patients after TAVI while satisfying the trial’s composite safety criterion, but further research is needed to determine whether this strategy improves clinical outcomes.

Source: Dodgson CS, et al. Anticoagulation monotherapy vs antiplatelet monotherapy after transcatheter aortic valve implant: the ACASA-TAVI randomized clinical trial. JAMA. Published online August 30, 2026. doi:10.1001/jama.2026.17036