Comparison of the Correlation Between Coagulation Indices and Rivaroxaban Concentrations

Background: Rivaroxaban has predictable pharmacokinetics and pharmacodynamics. However, monitoring rivaroxaban concentrations should be provided for special patients with hepatic insufficiency, high bleeding risk, and high thrombotic risk. Objective: This study aimed to correlate chromogenic anti-Xa assay, prothrombin time (PT), activated partial thromboplastin time (APTT), thromboelastogram reaction time (TEG R-time), and rivaroxaban concentration measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) (MS-Riva). Methods: Peripheral venous blood was collected from recruited patients 30 minutes before and 2 to 4 hours after drug administration. High-performance liquid chromatography-tandem mass spectrometry and chromogenic anti-Xa assay measured rivaroxaban concentration. Different assays were compared by Pearson correlation coefficient and Bland-Altman analysis. Results: A total of 104 patients with 191 plasma were included in the study. Overall analysis shows that chromogenic anti-Xa assay, PT, APTT, and TEG R-time strongly correlated with MS-Riva ( r = 0.986; r = 0.884; r = 0.741; r = 0.739; P < 0.001). Rivaroxaban peak concentration detected by HPLC-MS/MS (MS-peak) showed a very strong correlation with the chromogenic anti-Xa assay ( r = 0.977, P < 0.001) and moderate correlation with PT, APTT, and TEG R-time ( r = 0.670; r = 0.571; r = 0.481, P < 0.001). Rivaroxaban trough concentration detected by HPLC-MS/MS (MS-trough) correlated strongly with the chromogenic anti-Xa assay ( r = 0.884, P < 0.001), weakly with APTT ( r = 0.313; P = 0.043), and not significantly with PT and TEG R-time ( P = 0.140; P = 0.341). Conclusion and Relevance: High-performance liquid chromatography-tandem mass spectrometry/MS is the preferred choice for monitoring peak and tough concentrations, followed by anti-Xa, while PT is only suitable for peak concentrations. This study can help the clinicians to better adjust the medication regimen and reduce the risk of recurrence of thrombosis as well as the risk of bleeding.