Key result
NOAC monotherapy after TAVI reduced HALT versus aspirin (16.2% vs 28.6% (27/167 vs 48/168)) with noninferior safety.
Why the trial?
The optimal antithrombotic regimen after TAVI is unsettled: aspirin is standard, yet leaflet thrombosis is frequent and its prevention unproven. ACASA-TAVI asked whether NOAC monotherapy protects the valve better without excess bleeding.
Does NOAC monotherapy reduce valve leaflet thrombosis and maintain safety compared to ASA monotherapy in patients aged 65-80 years undergoing TAVI for severe aortic valve stenosis?
Population
360 patients aged 65–80 undergoing TAVI for severe AS (mean 74.5; 37% female)
Comparison
Factor Xa NOAC monotherapy vs aspirin (ASA) monotherapy for 12 months
Design
Randomized (1:1), open-label, blinded-endpoint trial at 3 Norwegian centres
Follow-up
12 months
Authors
Interventional · Oslo University Hospital
Looking forward to discussing ACASA-TAVI with this community.
ACASA-TAVI co-author
Replying to
Looking forward to discussing ACASA-TAVI with this community.
Wouldn’t it be better to diagnose subclinical valve thrombosis first with CT followed bij randomisation of only positive patients to continuing ASA vs DOAC (POPULAR ATLANTIS)
Experts see ACASA-TAVI as intriguing but not practice-changing, noting that reduced leaflet thrombosis is a surrogate endpoint and the trial was too small to settle whether NOACs improve hard clinical outcomes after TAVI.
The reaction is cautious: most commentators acknowledge that NOAC monotherapy cut leaflet thrombosis compared with aspirin, but they stress the trial relied on imaging surrogates rather than strokes or mortality. The live question is whether a larger, outcomes-powered trial can justify switching younger, lower-risk TAVI patients away from single antiplatelet therapy.
Multiple clinicians agree the trial does not warrant a change in practice because it was not powered for hard clinical outcomes and leaflet thrombosis on CT remains a surrogate endpoint.
Whether reducing leaflet thrombosis on CT translates into fewer strokes, better valve durability, or improved survival remains unknown. Experts note a dedicated clinical-outcomes trial comparing monotherapy strategies is still needed, and whether younger, lower-bleeding-risk patients represent a subgroup that could benefit from NOACs is unresolved.
Reads the combined signal from ACASA-TAVI and NOTION-4 as less leaflet thrombosis but more bleeding with anticoagulation, concluding that single antiplatelet therapy should remain the default post-TAVI strategy.
Argues that as TAVI implants become more personalized, antithrombotic therapy should follow. In younger patients under 80 with low bleeding risk, an oral anticoagulant could reduce leaflet thrombosis and potentially improve durability without increasing serious bleeding.
Cath Lab After Hours · Interventional cardiology education account · Sep 14 Endpoint critique Warns that better valve imaging does not equal better patient outcomes and that a 360-patient surrogate-endpoint trial with a mixed DOAC strategy should not overturn current guidance against routine anticoagulation. Original post
NOAC monotherapy reduces TAVI leaflet thrombosis with noninferior safety; extends antithrombotic options beyond aspirin in moderate-risk patients.
JAMA · ESC 2026 · RCT. After TAVI, NOAC alone cut leaflet thrombosis versus aspirin, with noninferior safety. ACASA-TAVI: Anticoagulation Monotherapy vs Antiplatelet Monotherapy After Transcatheter Aortic Valve Implant The optimal antithrombotic regimen after TAVI is unsettled: aspirin is standard, yet leaflet thrombosis is frequent and its prevention unproven. Does NOAC monotherapy reduce valve leaflet thrombosis and maintain safety compared to ASA monotherapy in patients aged 65-80 years undergoing TAVI for severe aortic valve stenosis? 360 participants, Randomized (1:1), open-label…. TAVI valve leaflet thrombosis defined as the presence of hypoattenuated leaflet thickening (HALT) on blinded…: NOAC 16.2% vs ASA 28.6%. RR 0.55 (95% CI 0.37–0.82), P=.004. Read with care. VARC-3 bleeding, thromboembolic events, or death (co-primary safety) occurred in 13 (7.5%) vs 19 (10.6%). In-world sources disagree on the primary HALT rates, so the efficacy result needs manual reconciliation. HALT is a subclinical imaging endpoint; its link to clinical events is not established by this trial. Where experts stand: Experts see ACASA-TAVI as intriguing but not practice-changing, noting that reduced leaflet thrombosis is a surrogate endpoint and the trial was too small to settle whether NOACs improve hard… Stefano Garzon (Hospital Israelita Albert Einstein): SAPT remains the standard of care after TAVI Alejandro Lara-García (Interventional cardiologist, Hospital La Paz): Younger, lower-bleeding-risk TAVI patients may gain durability from NOAC without added major bleeding Synapse summaries of their public posts Read the evidence. See where experts stand. synapsesocial.com/papers/6a8fbb6517152b56e6b64830
| Outcome | NOAC | ASA |
|---|---|---|
| HALT (valve leaflet thrombosis) on 4D CT at 12 months | ||
| Co-primary efficacy · in-world sources disagree (abstract 16.2% vs 28.6%; structured record 17.2% vs 32.6%); values withheld pending review |
Safety
VARC-3 bleeding, thromboembolic events, or death (co-primary safety) occurred in 13 (7.5%) vs 19 (10.6%); RD −3.3% (95% CI −9.5% to 2.8%); noninferior (p<0.001).
Design limitations
In-world sources disagree on the primary HALT rates, so the efficacy result needs manual reconciliation.
Subgroup caution
HALT is a subclinical imaging endpoint; its link to clinical events is not established by this trial.
Representation
Findings apply to patients aged 65–80 without another indication for anticoagulation.
Does NOAC monotherapy reduce valve leaflet thrombosis and maintain safety compared to ASA monotherapy in patients aged 65-80 years undergoing TAVI for severe aortic valve stenosis?
Relative Risk: 0.55 (95% CI 0.37–0.82)
Absolute Event Rate: 16.2% vs 28.6%
p-value: p=.004
In patients aged 65-80 undergoing TAVI, NOAC monotherapy for 12 months significantly reduced subclinical valve leaflet thrombosis and was noninferior for clinical safety events compared to standard aspirin monotherapy.
Journal, society, and media accounts. Useful signal, not independent expert judgment.
Dodgson et al. (2026) conducted an RCT in Severe aortic valve stenosis (n=360). NOAC monotherapy vs. Acetylsalicylic acid (ASA) monotherapy was evaluated on TAVI valve leaflet thrombosis defined as the presence of hypoattenuated leaflet thickening (HALT) on blinded core laboratory 4-dimensional cardiac computed tomographic (CT) scan at 12 months (RR 0.55, 95% CI 0.37 to 0.82, p=.004). NOAC monotherapy reduced TAVI valve leaflet thrombosis at 12 months compared to ASA monotherapy (16.2% vs 28.6% (27/167 vs 48/168); risk ratio 0.55, 95% CI 0.37-0.82; P=0.004) and was noninferior for safety (7.5% vs 10.6%; risk difference -3.3%, 95% CI -9.5% to 2.8%; P for noninferiority <0.001).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:
