Residual rivaroxaban exposure after discontinuation of anticoagulant therapy in patients undergoing cardiac catheterization.

PURPOSE: Patients treated with direct oral anticoagulants (DOACs) frequently undergo interventional procedures requiring temporary discontinuation of anticoagulant therapy. Little is known about remaining peri-procedural exposure to rivaroxaban in real-world patients.
METHODS: Fifty-six patients with rivaroxaban treatment and scheduled cardiac catheterization were included in this prospective, observational, and single-center study. Rivaroxaban concentrations were determined by LC-MS/MS and a chromogenic anti-Xa assay. Population pharmacokinetic modeling was carried out on LC-MS/MS concentration data using NONMEM software, and results were applied to Monte Carlo simulations to predict appropriate rivaroxaban discontinuation intervals.
RESULTS: Rivaroxaban concentrations ranged from <LLOQ to 300.6 ng/ml at the time of admission to hospital and from <LLOQ to 55.5 ng/ml at the beginning of the procedure. Times since last rivaroxaban intake were (mean ± SD) 51.0 ± 31.7 h (admission) and 85.5 ± 36.8 h (start catheterization). LC-MS/MS and anti-Xa assay results were in good agreement (r = 0.958); however, the anti-Xa assay may underestimate low rivaroxaban concentrations and overestimate rivaroxaban exposure when performed on plasma samples contaminated with heparins. Pharmacokinetics of rivaroxaban were adequately described, and simulations predicted that 95% of patients will have rivaroxaban concentrations ≤ 28.4 ng/ml (15 mg dose group) and ≤ 31.9 ng/ml (20 mg dose group) after 48 h of discontinuation.
CONCLUSIONS: In the majority of patients, rivaroxaban plasma concentrations dropped below 30 ng/ml after 48 h of treatment discontinuation which is considered hemostatically safe before surgery with high bleeding risk. For accurate determination of low rivaroxaban concentrations, LC-MS/MS is the preferred choice.