Is anti-factor Xa chromogenic assay for Rivaroxaban appropriate in clinical practice? Advantages and comparative drawbacks.
Thromb Res
; 136(2): 396-401, 2015 Aug.
Article
in En
| MEDLINE
| ID: mdl-26058941
ABSTRACT
INTRODUCTION:
No routine monitoring is required with factor Xa inhibitor rivaroxaban. Yet, its titration must be adapted, and its misuse may lead to increased risk of bleeding; therefore, therapeutic rivaroxaban monitoring might help in specific situations. MATERIAL ANDMETHODS:
As asked by clinicians of our medical center, we measured rivaroxaban plasma concentrations in real conditions of use and checked their corresponding prescriptions. Measurement of 112 samples from 94 consecutive patients was performed with a Biophen LRT® anti-Xa chromogenic assay and compared blindly to the HPLC-MSMS "gold standard" method. Rivaroxaban was effectively given to 80 out of 94 patients but a mere 57% through an adequate prescription (within the scope of indications/titration). All chromogenic measurements were over the pre-specified 30ng/ml LOQ, whereas only 98 /114 samples had quantifiable rivaroxaban with HPLC-MSMS (LOQ 1ng/ml). Correlation between the two methods and linear regression were highly significant (p<0.0001). However, chromogenic values (mean 141.6ng/ml[96.6]) overestimated HPLC-MSMS values (119.7ng/ml[79.5]) by 22ng/ml according to Bland-Altman analysis (p<0.001). After re-assessing the chromogenic LOQ at 52ng/ml, 83 quantifiable samples had a mean concentration of 176.9ng/ml as compared to 158.5ng/ml with HPLC-MSMS, with no false positive anymore.CONCLUSIONS:
In our medical center, rivaroxaban concentrations could be assessed by a rapid chromogenic method. Its pre-specified LOQ proved too high after being checked "on site" against HPLC-MSMS. Prescriptions for rivaroxaban were not optimal. An overestimated LOQ may impair observance monitoring or predispose patients to either risky thrombolysis or otherwise adjournable surgery in clinical practice.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Thrombosis
/
Blood Chemical Analysis
/
Factor Xa
/
Rivaroxaban
Type of study:
Clinical_trials
/
Diagnostic_studies
Limits:
Aged
/
Female
/
Humans
/
Male
Language:
En
Journal:
Thromb Res
Year:
2015
Type:
Article
Affiliation country:
France