Low-dose Rivaroxaban versus Warfarin in Patients Early after Bioprosthetic Valves Replacement

This study aims to evaluate the effects of low-dose rivaroxaban in patients during the initial three months following bioprosthetic valve replacement. In this retrospective study, we compared low-dose rivaroxaban (15 mg once daily) with dose-adjusted warfarin (target international normalized ratio of 2.0 to 3.0) in patients who received a bioprosthetic valve replacement within the first three months. Primary efficacy outcome was the incidence of thromboembolic complications, while primary safety outcome was the incidence of bleeding within three months post-surgery. A total of 380 patients were enrolled at a large teaching hospital. The primary efficacy outcome occurred in 1 patient in both the warfarin and the rivaroxaban groups (p < 0.001 for noninferiority). There were no deaths in either group. 19 patients experienced the primary safety outcome; specifically, bleeding events occurred in 7 patients in the rivaroxaban group and in 12 patients in the warfarin group (7/178 vs. 12/189, p < 0.001 for noninferiority). After propensity score matching, the prevalence of clinical thromboembolic events was comparable between the two groups (1/130 vs. 0/130, p < 0.001 for noninferiority). The incidence of bleeding events in the rivaroxaban group was found to be noninferior to that in the warfarin group (6/130 vs. 6/130, p < 0.001 for noninferiority). In the early three months following bioprosthetic valve replacement, low-dose rivaroxaban demonstrated noninferiority to warfarin with respect to the incidence of primary outcomes (death, major cardiovascular events, or major bleeding).