Prospective study on the impact of different antithrombotic therapies on subclinical leaflet thickening and its temporal dynamics in transcatheter aortic valves-The NOTION-4 trial.

Background: Transcatheter aortic valve replacement (TAVR) has become the standard-of-care treatment for a majority of patients with severe, symptomatic aortic stenosis. The postprocedural antithrombotic therapeutic management is still a topic of debate and could affect the incidence of HALT, a phenomenon which can be assessed by 4-dimensional computed tomography (4DCT).

Trial Design: The NOTION-4 trial is a randomized controlled trial comprising TAVR patients with no indication for oral anticoagulant (OAC) therapy, comparing lifelong single antiplatelet therapy (standard arm) versus early 3-month direct oral anticoagulant (DOAC) therapy followed by single antiplateletet therapy (experimental arm). The incidence of HALT and clinical endpoints will be evaluated in both groups at 3 months, 1 year and 5 years after randomization. The primary endpoint is the number of patients with at least 1 bioprosthetic aortic valve leaflet with HALT as assessed by cardiac 4DCT imaging at 1 year. The trial is powered for superiority testing and started enrollment in 2021. In total, 324 patients will be included. The last patient is expected to be enrolled by the end of 2024 and the primary endpoint is to be presented in 2026.

Conclusion And Perspective: The NOTION-4 trial aims to study whether an early 3-month DOAC therapy after TAVR can result in a sustained lower incidence of HALT in transcatheter aortic valves. This trial holds the potential to give valuable insights into whether early OAC therapy should be integrated in future guidelines for post-TAVR antithrombotic therapeutic management.

Trial Registration: NOTION-4, ClinicalTrials.gov ID NCT06449469, https://clinicaltrials.gov/study/NCT06449469.