Effects of rivaroxaban on vascular endothelial function and circulating endothelial progenitor cells: a randomized controlled trial

Abstract Background Combination of low dose rivaroxaban with aspirin was shown to reduce major adverse cardiovascular events when compared to aspirin monotherapy in COMPASS trial. The beneficial effect of rivaroxaban beyond factor Xa inhibition remains unknown. Purpose This randomized controlled trial explored the effects of rivaroxaban on vascular endothelial function and circulating endothelial progenitor cells in patients with stable atherosclerotic disease. Methods An investigator-initiated, investigator-blinded, single-center randomized clinical trial was conducted from May 2021 to August 2023. 142 patients were randomized in 1:1 ratio to receive rivaroxaban 2.5mg twice daily plus aspirin 100mg once daily (Treatment Group) or aspirin 100mg once daily (Control Group) and had follow-up for 3 months. The primary outcome was change of flow mediated dilation (FMD) from baseline to 3-month follow-up. Key secondary outcomes included change of circulating endothelial progenitor cells (CD45+/34+/133+, CD45+/34+/KDR+), platelet activation marker (CD41+/62p+), inflammatory marker (CD14+/11b+) and thrombo-inflammatory maker (CD14+/42b+) measured by flow cytometry, as well as platelet function (aspirin reaction unit, ARU) measured by blood biochemistry. Intention-to-treat analysis was performed with analysis of covariance (ANCOVA) and P < 0.05 was considered statistically significant. Results Overall, 142 patients were enrolled in the study. One patient was excluded from analysis due to protocol deviation. Among the remaining 141 patients (78.8% male and mean age 69±9 years), there were 71 in Treatment Group and 70 in Control Group. The recruited patients had a high prevalence of cardiovascular comorbidities including 76.6% with hypertension, 50.4% with hyperlipidemia, 45.4% with diabetes, and 92.2% with percutaneous coronary intervention. At 3 months, Treatment Group had greater FMD improvements (+2.18±5.66% vs +1.57±5.07%, P=0.03), and more reduction in platelet activation marker (-0.33±13.55% vs +5.78±21.60%, P=0.01). There was no significant change in circulating endothelial progenitor cells, inflammatory marker, thrombo-inflammatory maker, and platelet function. Minor bleeding occurred in 2 patients (2.82%) in Treatment Group and none in Control Group (P>0.05). Conclusion In patients with stable atherosclerotic disease, addition of rivaroxaban to aspirin was well tolerated, and it improved vascular endothelial function and reduced platelet activation.