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

Alexander Kaserer,Burkhardt Seifert,Jan-Dirk Studt,Philipp Stein,Andreas Schedler,Donat R Spahn

doi:10.1186/s13741-019-0128-9

Alexander Kaserer, Burkhardt Seifert + Show 4 more

Open Access

https://doi.org/10.1186/s13741-019-0128-9

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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.

Highlights

While 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
Study goals Our study aimed to investigate the impact of anti-Xa determined RXA plasma concentration as determined by anti-Xa assay on the standard coagulation tests PT (Quick test and International normalized ratio (INR)) and activated partial thromboplastin time (aPTT)
Renal function was mildly impaired with a mean glomerular filtration rate (GFR) of 68 ± 27 ml/min and mean serum creatinine of 103 ± 63 mcmol/l

Summary

Introduction

While 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). For determining RXA plasma concentration, highperformance liquid chromatography-mass spectrometry (HPLC-MS) is considered the gold standard (Asmis et al 2012). This method is time-consuming, expensive, and not suitable for routine clinical use. While most university hospitals or other large hospitals have introduced anti-Xa assays for RXA, these are not readily available to smaller hospitals often relying on (2019) 8:15 routine coagulation tests such as prothrombin time (PT) and activated partial thromboplastin time (aPTT). In German-speaking countries, a plasma sample’s tissue factor-induced coagulation time is typically expressed as Quick value (%) in relation to that of a normal plasma pool; the longer the PT, the lower the Quick value (%)

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