DOAC monotherapy after TAVI reduced leaflet thrombosis against aspirin

Design

Randomised, open-label, blinded end point trial, 3 centres

Population

360 patients aged 65–80 undergoing TAVI for severe aortic stenosis, Norway

Primary outcome

HALT on 4D CT at 12 months; bleeding, thromboembolism and death composite

Effect

HALT 16.2% vs 28.6%, RR 0.55 (95% CI 0.37–0.82); safety 7.5% vs 10.6%, non-inferior

ACASA-TAVI randomised 360 patients aged 65–80 undergoing TAVI at three Norwegian centres to 12 months of factor Xa inhibitor monotherapy or aspirin monotherapy. Patients did not need atrial fibrillation to take part. The efficacy end point was hypoattenuated leaflet thickening (HALT) on blinded 4D CT at 12 months; the safety end point combined bleeding, thromboembolic events and death.

HALT occurred in 16.2% on a DOAC and 28.6% on aspirin (risk ratio 0.55). The safety composite was 7.5% against 10.6% and met non-inferiority.

This matters as TAVI moves into younger patients, for whom valve durability counts. It contrasts with earlier trials in which anticoagulation after TAVI raised harm. The key limitation is that HALT is an imaging finding; whether preventing it lengthens valve life has not been shown.

• Aspirin remains the default after TAVI without another indication for anticoagulation
• Consider a DOAC in selected younger TAVI patients at low bleeding risk after heart team discussion
• Assess bleeding risk formally before choosing anticoagulation
• Do not order routine CT for HALT outside a protocol

Why it matters

It reopens anticoagulation after TAVI, which earlier trials had closed, for patients who will need their valve to last.

Don't overread it

Leaflet thickening on CT is a surrogate; this trial does not show that preventing it improves valve durability or clinical outcomes.

The statistics, in plain English

Risk ratio 0.55 (95% CI 0.37–0.82) means leaflet thickening was about 45% less common with a DOAC. The safety difference of −3.3% (−9.5% to 2.8%) crosses zero, so the finding is non-inferiority, not superiority. The trial was not powered for clinical events such as stroke or valve failure.

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