Standard coagulation assays alone are not sufficient to exclude surgically relevant rivaroxaban plasma concentrations

Abstract

BackgroundWhile mainly larger hospitals have introduced routine anti-Xa assays for rivaroxaban (RXA), these are not readily available to smaller hospitals often relying on routine coagulation tests such as prothrombin time (PT) and activated partial thromboplastin time (aPTT).The aim of our study was to investigate the effect of RXA plasma concentration on the standard coagulation tests PT (Quick test and INR) and aPTT in a large group of real-life patients. We further assessed whether normal results of these standard coagulation assays are sufficient to exclude surgically relevant RXA plasma concentration, defined as > 50 mcg/l.MethodsThis retrospective study included all patients between 2012 and 2016 where anti-Xa (calibrated for RXA), PT (Quick test and INR), and/or aPTT were determined from the same sample. PT is expressed as Quick value (% of normal plasma pool). In total, 1027 measurements in 622 patients were eligible for analysis: 752 measurements of 505 patients for Quick/INR and 594 measurements of 417 patients for aPTT.ResultsA moderate correlation of PT/Quick (Pearson's correlation coefficient − 0.59; p < 0.001), INR (Pearson's correlation coefficient 0.5; p < 0.001), and aPTT (Pearson's correlation coefficient 0.53; p < 0.001) with RXA plasma concentration was observed. However, in 50% of all samples with a normal PT/Quick, in 25% of all samples with a normal INR and in 80% of all samples with a normal aPTT residual RXA plasma concentration was surgically relevant.ConclusionAlthough a moderate correlation of RXA plasma concentration with PT/Quick, INR, and aPTT was observed, standard coagulation assays are not sufficient to exclude surgically relevant RXA plasma concentrations.

Poor Correlation of Rivaroxaban Concentration with the Routine Coagulation Screening Test in Chinese Patients with Atrial Fibrillation

“…Moreover, the mechanism of factor Xa inhibition with rivaroxaban also makes the TT an undesirable assay. Overall, we confrmed that routine coagulation assays were not sufcient to exclude a clinically relevant rivaroxaban plasma concentration [29][30][31].…”

Activated Partial Thromboplastin Time or Prothrombin Time Prolongation During Rivaroxaban Administration: Clinical Risk Factors and Outcomes Analysis

“…[7][8][9][10][11][12][13][14][15] Nevertheless, a prolonged PT and/or aPTT in a patient with known DOACs exposure should be expected and is likely to be drug related. [16][17][18] In the past, studies have explored the influence of DOACs on routine coagulation assays, or the relationship between drug concentration and coagulation test results. 19,20 However, little is known about the clinical characteristics of patients with prolonged PT and/or aPTT while receiving the standard pharmacotherapy of DOACs such as rivaroxaban.…”