Antithrombotic treatment regimen following transcatheter aortic valve replacement (TAVR) is not evidence-based. Apixaban, a non-vitamin K direct anticoagulant (NOAC) was shown to be superior to VKA and superior to aspirin to prevent cardioembolic stroke in non-valvular atrial fibrillation. It may have the potential to reduce TAVR-related thrombotic complications including subclinical valve thrombosis along with a better safety than the standard of care.

ATLANTIS is a multicenter, randomized, phase IIIb, prospective, open-label, superiority study comparing standard of care (SOC Group) versus an apixaban-based strategy (Anti-Xa Group) after successful TAVR (ClinicalTrials.gov NCT 02664649). Randomization is stratified according to the need for chronic anticoagulation therapy for a reason other than the TAVR procedure. In the experimental arm, patients receive 5 mg bid of apixaban or a reduced dose of 2.5 mg bid according to the drug label or when apixaban is combined with antiplatelet therapy. In the control arm, patients receive VKA therapy if there is an indication for oral anticoagulation or antiplatelet therapy alone (single or dual) or the combination of both if needed. The primary study end point is the composite of all-cause death, TIA/stroke, myocardial infarction, symptomatic valve thrombosis, pulmonary embolism, deep venous thrombosis, systemic embolism, life-threatening, disabling or major bleeding, according to the Valve Academic Research Consortium definitions.

ATLANTIS tests the superiority of an apixaban-based strategy versus the recommended standard of care strategy to reduce the risk of post-TAVR thromboembolic and bleeding complications in an all comer population.