Heuzey, J.‐Y. Le

Abstract Introduction Non-vitamin-K oral anticoagulants (NOACs) were recommended in preference to oral vitamin K antagonists (VKAs) in the 2020 updated guidelines for stroke prevention in atrial fibrillation (AF), from the European Society of Cardiology (ESC). Rivaroxaban is a NOAC that is approved in many countries worldwide for reducing the risk of stroke or systemic embolism in patients with nonvalvular atrial fibrillation (AF). Purpose To explore the baseline characteristics, dosing and 2-year outcomes of patients with AF treated with rivaroxaban. Methods RIVaroxaban Evaluation in Real Life setting (RIVER) is a prospective international, multicenter registry of patients with newly diagnosed non-valvular AF treated with rivaroxaban for the prevention of thromboembolic stroke and at least one investigator-determined risk factor for stroke. Results A total of 5043 patients were enrolled into RIVER between January 2015 and June 2017. Mean (SD) age at diagnosis was 69.5 (11.0) years and 55.7% were males. Caucasian patients represented the largest proportion of patients in RIVER (80.3%), followed by Asians (5.5%) and hispanic/latino (3.7%). Almost all patients (98.5%) were prescribed a single daily dose of rivaroxaban, most commonly 20 mg (77.3%) and 15 mg (20.4%), while a 10 mg dose was prescribed in only 2.3% of patients. During the 2-year follow-up, the rates (95% CI) of all-cause mortality, stroke/SE, and major bleeding were 2.75 (2.43 to 3.12), 0.89 (0.72; 1.11), and 1.26 (1.05 to 1.52) per 100 person years, respectively (Figure 1). The most common cardiovascular cause of death was congestive heart failure (30.4%) and myocardial infarction (11.4%). Leading non-cardiovascular causes of death were malignancy (27.4%), respiratory failure (18.9%) and infections/sepsis (13.2%). Over 2 years, 710 (14.1%) of patients discontinued rivaroxaban. The corresponding proportions at 6 months and 1 year were 7.8% and 10.8%, respectively. Out of all the patients who discontinued, 62 (8.7%) restarted rivaroxaban during their follow-up (Table 1). Conclusion During 2 years of follow up in the international, prospective RIVER registry, rivaroxaban treatment for AF was associated with low rates of stroke or major bleeding. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by an unrestricted research grant from Bayer AG, Berlin, Germany, to TRI, London, UK. This work is supported by KANTOR CHARITABLE FOUNDATION for the Kantor-Kakkar Global Centre for Thrombosis Science.

Abstract Introduction Rivaroxaban is recommended as an option for anticoagulation in patients with nonvalvular atrial fibrillation (AF) with one or more risk factors for stroke. The approved/recommended rivaroxaban dose for stroke prevention in patients with atrial fibrillation (AF) is solely based on renal function: 20 mg once daily (od) for patients with a creatinine clearance [CrCl] ≥50 ml/min and 15 mg od in patients with CrCl 15–49 mL/min). Purpose To assess the patterns of rivaroxaban prescription as per the creatinine clearances levels and to assess the impact of the rivaroxaban dosing on the rate of events at 2-year follow-up in patients with AF. Methods RIVaroxaban Evaluation in Real Life setting (RIVER) is a prospective international registry of patients with newly diagnosed non-valvular AF treated with rivaroxaban for the prevention of thromboembolic stroke and at least one investigator-determined risk factor for stroke. Adjusted hazard ratios (HRs) were obtained through Cox proportional-hazard model. Results Among 3402 patients with normal renal function (CrCl ≥50 mL/min), 82.1% were prescribed the recommended rivaroxaban dose of 20 mg (od) at baseline. Among 524 patients with moderate or severe renal impairment (CrCl 15–50 mL/min), 55.3% patients received rivaroxaban 15 mg (od), 39.9% received 20 mg (od) and 4.2% 10 mg (od). Non-recommended dosing was rare in patients younger than 70 (13.5%) but more frequent in older patients (28.8%). Non-recommended low dosing was more frequent in Asians (38.9%), compared to non-Asian patients (13.8%). Regarding clinical outcomes, adjusted hazards ratios (HR, presented with 95% confidence intervals) showed that the non-recommended low dosing (<20 mg od) was associated with higher risk of non-cardiovascular mortality (HR 2.09 (1.16–3.77)) in patients with normal renal function. The non-recommended high dosing (>15 mg od) was associated with lower risk of all-cause mortality (HR 0.63 (0.42–0.93)) and cardiovascular mortality (HR 0.32 (0.13–0.77)) and higher risk of major bleeding (HR 2.86 (1.49–5.50)) in patients with moderate to severe renal impairment (figure 1 and 2). Conclusion In patients with normal renal function, non-recommended low dose rivaroxaban was associated with increased cardiovascular mortality without reducing the risk of major bleeding compared to recommended dosing. In patients with CrCl <50 ml/min, non-recommended high dose rivaroxaban was associated with reduced cardiovascular mortality but at the cost of increased major bleeding. These observational data largely support the reduction of rivaroxaban dosing according to renal function but educational strategies are needed to ensure that rivaroxaban is used appropriately. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by an unrestricted research grant from Bayer AG, Berlin, Germany, to TRI, London, UK, which sponsors the RIVER registry. This work is supported by KANTOR CHARITABLE FOUNDATION for the Kantor-Kakkar Global Centre for Thrombosis Science.