According to the European Society of Cardiology, non-vitamin K antagonist oral anticoagulant (NOAC) therapy reduces imaging signs of clot formation on new heart valves by 45% compared with antiplatelet therapy following transcatheter aortic valve implantation (TAVI), without compromising patient safety.
ACASA-TAVI Trial Results Presented at ESC Congress 2026
The ACASA-TAVI trial, presented during a Hot Line session at the ESC Congress 2026 and published simultaneously in JAMA, investigated optimal antithrombotic therapy for patients undergoing TAVI. Use of the procedure for symptomatic severe aortic valve stenosis has grown rapidly over the past two decades. As indications expand to include younger patients with longer expected lifespans, bioprosthetic valve durability becomes critical.
Thrombus formation on bioprosthetic valve leaflets is a preventable cause of early valve dysfunction, linked by researchers to increased risks of stroke and death. According to Doctor Øyvind Lie, principal investigator of the trial from Oslo University Hospital Rikshospitalet in Norway, a knowledge gap previously existed regarding the best antithrombotic regimen after the procedure. Current guidelines recommend either an antiplatelet agent like acetylsalicylic acid or a NOAC, but only when an independent indication for anticoagulation is present.
Did you know? Thrombus formation on newly implanted heart valve leaflets can lead to early valve dysfunction and has been linked to an elevated risk of stroke and patient mortality.
Head-to-Head Comparison of NOAC Monotherapy Versus Aspirin
To address the knowledge gap, researchers conducted an investigator-initiated trial across three hospitals in Norway. The study enrolled 360 consecutive patients aged 65 to 80 years who had undergone successful TAVI. Participants were randomized in a 1:1 ratio to receive either 12 months of NOAC monotherapy—comprising apixaban, edoxaban, or rivaroxaban—or acetylsalicylic acid, with clopidogrel substituted for aspirin intolerance or prior use.
Researchers assessed the primary efficacy endpoint via cardiac computed tomography at 12 months, measuring hypo-attenuated leaflet thickening as an indicator of subclinical leaflet thrombosis. The primary safety endpoint evaluated a composite of Valve Academic Research Consortium-3 bleeding events, thromboembolic events, and all-cause death at the 12-month mark.
Reduction in Leaflet Thrombosis Without Increased Safety Risks
Data show that imaging signs of leaflet thrombosis dropped significantly by 45% in patients receiving NOACs compared to those on aspirin at 12 months. Specifically, thrombosis signs appeared in 17.2% of the NOAC group versus 32.6% of the aspirin group, yielding a risk ratio of 0.55 with a 95% confidence interval from 0.37 to 0.82 and a p-value of 0.004.
Safety outcomes remained favorable for the anticoagulant group. Noninferiority was demonstrated between the NOAC and aspirin cohorts for the primary safety endpoint, which occurred in 7.5% of NOAC patients compared to 10.6% of aspirin patients, with a risk difference of −3.3 and a 95% confidence interval ranging from −9.5% to 2.8%.
Pro Tip: Researchers plan to track trial participants over a 10-year period to evaluate the long-term impact of NOAC monotherapy on bioprosthetic valve durability and clinical outcomes.
Frequently Asked Questions
What was the main finding of the ACASA-TAVI trial?
According to the European Society of Cardiology, anticoagulation with a NOAC reduced imaging signs of subclinical leaflet thrombosis by 45% compared with antiplatelet therapy at 12 months after TAVI.
Did NOAC monotherapy increase safety risks for patients?
No. The trial demonstrated that the safety profile of NOACs was noninferior to aspirin regarding bleeding events, thromboembolic events, and all-cause mortality.
How long will the ACASA-TAVI trial participants be monitored?
Researchers will continue to follow trial participants over a 10-year period to assess the long-term effects of NOAC monotherapy on valve durability.
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