Edoxaban Monotherapy and Incidence of Transcatheter Heart Valve Leaflet Thrombosis - The Rotterdam Edoxaban (REDOX) Study.

Background: Trials comparing non-vitamin K oral anticoagulant (NOAC) versus antiplatelet-based strategies have shown a reduction of subclinical leaflet thrombosis at the cost of increased mortality and major-bleedings. NOACs were often combined with antiplatelet therapy.

Aims: The Rotterdam Edoxaban (REDOX) study aimed to evaluate the impact of edoxaban monotherapy on the incidence of hypo-attenuated leaflet thickening (HALT) and reduced leaflet motion (RLM) and to evaluate safety in terms of mortality, thromboembolic events and major bleeding.

Methods: The REDOX study is a single-arm, open-label trial including patients after successful transcatheter aortic valve implantation (TAVI) with no formal indication for oral anticoagulation or dual antiplatelet therapy. Patients received edoxaban monotherapy for 3 months, followed by multislice computed tomography (MSCT). The primary endpoint was the occurrence of HALT. Clinical follow-up continued up to 1 year after TAVI.

Results: We included 58 patients, of which 50 reached study completion including MSCT scanning and eight withdrew consent before end of study. At 3-months follow-up, HALT of any grade was detected in 12.0% (95% confidence interval (CI): 5.0%-23.1%) of patients. HALT grade ≥ 3 occurred in 4.0% (95% CI: 0.8%-12.2%) of patients. At 1 year follow-up, all patients were alive and free of disabling strokes. Three patients had a non-disabling stroke and one patient had a major bleeding.

Conclusions: In the REDOX study, edoxaban monotherapy after TAVI was associated with a 12.0% incidence of any HALT and a 4.0% incidence of HALT grade ≥ 3. HALT was not associated with clinical events.