Duration‐Dependent Effects of Rivaroxaban on Inflammation and Valve Calcification in Aortic Stenosis: Clinical and In Vitro Insights

Direct oral anticoagulants (DOACs) inhibited calcification and extracellular matrix remodelling in valve interstitial cells (VICs). We assessed whether DOACs affect inflammation and calcification both in vitro and in stenotic aortic valves from patients with severe aortic stenosis (AS). We enrolled 52 patients with AS, including 22 with concomitant atrial fibrillation taking DOACs. Stenotic leaflets obtained during surgery were assessed for osteocalcin and bone morphogenetic protein 4 (BMP-4) by immunostaining. Serum interleukin-6 (IL-6), transforming growth factor-β (TGF-β) and matrix metalloproteinase-9 (MMP-9) were measured by ELISA. In vitro, VICs were treated with rivaroxaban (1 or 10 μg/mL) to evaluate BMP-4 and nuclear factor kappa B (NF-κB) expression via immunofluorescence. A median of DOAC therapy was 29.5 [Q1-Q3 20-48] months. The percentage of valvular osteocalcin, but not BMP-4 positive areas, was 39.6% lower in patients taking DOACs compared to the remainder (16.3% ± 4.8% vs. 27% ± 6.3%, p < 0.0001). Importantly, both valvular BMP-4 and osteocalcin expression correlated inversely with the duration of DOAC therapy (r = -0.92 and r = -0.78, both p < 0.0001). Additionally, DOAC-treated patients had lower serum MMP-9 (-58.1%, p < 0.0001) and TGF-β (-7.9%, p = 0.026) but not IL-6 (p = 0.092) compared to the non-DOAC group. DOAC duration correlated with MMP-9 (r = -0.89, p < 0.0001) and IL-6 (r = -0.63, p = 0.0015) levels. In vitro, rivaroxaban reduced NF-κB and BMP-4 expression in VICs in a time-dependent manner (all p < 0.01), regardless of dose. We showed that DOACs, in a time-dependent manner, exert anti-inflammatory and anti-calcific effects within aortic stenotic valves and in vitro in VICs, suggesting long-term DOAC therapy benefits.