Factor Xa inhibitor after TAVI reduces leaflet thickening against aspirin

Design

Randomised, open-label, blinded end-point trial

Population

360 patients aged 65–80 undergoing TAVI in Norway

Primary outcome

HALT on 4D CT at 12 months; VARC-3 bleeding, thromboembolism or death

Effect

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

ACASA-TAVI randomised 360 patients aged 65 to 80 undergoing TAVI at three Norwegian centres to 12 months of factor Xa inhibitor monotherapy or aspirin monotherapy. The trial was open-label with blinded end-point assessment and was published in JAMA in August.

Hypoattenuated leaflet thickening on core-laboratory CT at 12 months occurred in 16.2% on anticoagulation and 28.6% on aspirin (RR 0.55, 95% CI 0.37 to 0.82). The composite of VARC-3 bleeding, thromboembolism and death occurred in 7.5% versus 10.6% (risk difference −3.3%, −9.5% to 2.8%), meeting non-inferiority.

Leaflet thickening is an imaging finding whose link to valve durability and clinical events is not settled. The trial suggests anticoagulation is a reasonable option in selected patients without another indication, but it was not sized to show fewer strokes or longer valve life.

• Patients with an existing anticoagulation indication should stay on anticoagulant monotherapy after TAVI.
• For others, aspirin remains standard; anticoagulation is an option in low-bleeding-risk, younger TAVI patients.
• Consider follow-up CT where leaflet thrombosis is suspected clinically or echocardiographically.
• Assess bleeding risk formally before choosing an anticoagulant.

Why it matters

It reopens the post-TAVI antithrombotic choice as TAVI moves into younger patients who need durable valves.

Don't overread it

Less leaflet thickening on CT is a surrogate; the trial did not show fewer strokes or longer valve life.

The statistics, in plain English

The RR of 0.55 means about 45% less leaflet thickening, and the interval stays well below 1. The safety comparison shows non-inferiority, not superiority: the risk difference interval (−9.5% to 2.8%) includes no difference. The primary efficacy end point is a CT surrogate rather than a clinical event.

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