ACASA-TAVI Study Compares Anticoagulant Versus Antiplatelet Therapy After TAVR to Reduce Clots

September 24, 2026—Findings from the ACASA-TAVI trial showed that anticoagulation after transcatheter aortic valve replacement (TAVR) reduced imaging signs of clot formation on a new valve compared with antiplatelet therapy, without compromising safety.

The study was results were presented at the European Society of Cardiology’s ESC Congress 2026 and published by Christopher S. Dodgson, MD, et al in JAMA.

Øyvind Lie, MD, from Oslo University Hospital Rikshospitalet in Oslo, Norway, serves as Principal Investigator of the ACASA-TAVI trial.

The ESC press release noted that current recommendations are either an antiplatelet agent, such as acetylsalicylic acid (ASA; aspirin) or a nonvitamin K antagonist oral anticoagulant (NOAC) but only if an independent indication for anticoagulation exists.

ESC advised that the investigator-initiated trial enrolled 360 consecutive patients (ages, 65−80 years) who had undergone successful TAVR across three hospitals in Norway. Patients in the trial were randomized (1:1) to 12 months of a NOAC (apixaban, edoxaban, or rivaroxaban) or ASA (or clopidogrel if intolerant or if used before the trial).

The primary efficacy endpoint was the occurrence of hypoattenuated leaflet thickening, a measure of subclinical leaflet thrombosis, assessed by cardiac CT at 12 months. The primary safety endpoint was a composite of Valve Academic Research Consortium-3 bleeding events, thromboembolic events, and all-cause death at 12 months.

As reported in the ESC press release, the investigators found the following:

• For the primary efficacy endpoint, the occurrence of imaging signs of leaflet thrombosis was significantly reduced by 45% in patients who received NOACs compared with ASA at 12 months (17.2% vs 32.6%; risk ratio, 0.55; 95% CI, 0.37-0.82; P = .004).
• For the primary safety endpoint, noninferiority was demonstrated between NOAC and ASA groups (7.5% vs 10.6%; risk difference −3.3; 95% CI, −9.5% to 2.8%; P for noninferiority < .001).
• Two patients assigned to NOACs and 10 patients assigned to ASA died during the study.
• The overall number of bleeding events was low, but numerically higher in patients treated with ASA compared with NOACs, particularly for more severe bleeding events.

“Clinicians may perceive the bleeding risk of anticoagulants to be higher than that of antiplatelet agents, but we found in this study that life-threatening and lethal bleeding occurred only in patients in the ASA group,” commented Dr. Lie in the ESC press release.

He concluded, “We were able to show substantial reductions in signs of subclinical leaflet thrombosis with NOAC monotherapy, without compromising safety. Results from the ACASA-TAVI trial may establish a new antithrombotic treatment paradigm after TAVR and could be used to inform future guidelines. We will continue to follow the trial participants over a 10-year period, further investigating the impact of NOAC monotherapy on valve durability and clinical outcomes.”