PB0445 - Calibration of the International Normalized Ratio dedicated to Rivaroxaban according to WHO guidelines

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Mohamed CHEKKAL, Doctorate in medical sciences

Head of department
Medicine faculty. Oran1 university. Oran university establishment (EHU). Oran. Algeria.
Oran, Oran, Algeria

Co-Author(s)

NY

Nabil YAFOUR

Head of department
Department of hematology. EHU Oran. Medicine faculty. Oran1 unversity
Oran, Oran, Algeria
AA

Affaf ADDA

Head of unit
Department of hemobiology and blood transfusion. EHU Oran. Medicine faculty.Oran1 university. Oran. Algeria
Oran, Oran, Algeria
AB

Amina BOULENOUAR

Resident
Department of hemobiology and blood transfusion. EHU Oran. Medicine faculty.Oran1 university. Oran. Algeria
Oran, Oran, Algeria
NZ

Noujoum ZMOULI

Head of unit
Department of hemobiology and blood transfusion. EHU Oran. Medicine faculty.Oran1 university. Oran. Algeria
Oran, Oran, Algeria
ME

Mohamed ELHORRI

Head of unit
HMRUO
Oran, Oran, Algeria
AS

Amel Soulef SAADI OUSLIM

head of department
Department of biochemestery. EHU Oran. Medicine faculty. Oran1 unversity
Oran, Oran, Algeria
MB

Mohamed Nazim Bennaoum

Head of unit
Department of hemobiology and blood transfusion. EHU Oran. Medicine faculty.Oran1 university. Oran. Algeria
Oran, Oran, Algeria

Background: The arrival of Non- VKA Oral Anticoagulants (NOACs) has upset the landscape of antithrombotics. One of the most used is Rivaroxaban that has an anti Xa activity with predictable pharmacokinetics and pharmacodynamics and does not require routine monitoring except in certain situations such as surgery, drug interactions, hemorrhagic or thrombotic manifestations. In these situations what would be the routine test to use for monitoring: PT, PT Ratio, PT % activity, INRVKA, INRRivaroxaban or other tests?

Aims: Our objective was to establish a reliable and routinely available means for monitoring Rivaroxaban therapy by comparing inter-thromboplastin variations on different hemostasis tests: PT, PT Ratio, PT % activity, INRVKA and INR Rivaroxaban.
.

Methods: In a first step, the inter-reagent variability of routine tests (PT, PT Ratio, PT % activity, INRVKA) results using various thromboplastins (Recombiplastine®, Neoplastine plus®, PT fibrinogen®, PT fibrinogen HS Plus®) was evaluated by the average coefficient of variation tested in 60 patients under Rivaroxaban.

In a second step, we carried out a secondary calibration according to the “WHO 1999” guidelines to deduce the ISI of each thromboplastin tested and we calculated a specific INR for rivaroxaban (INR Rivaroxaban). We then evaluated the impact on the average CV in 60 patients under Rivaroxaban.

Results: The average CVs of PT and PT % activity were 15.96% and 12.37% respectively. Those of PT Ratio and INRVKA were 9.09% and 9.96%, respectively, while that of INR Rivaroxaban was 3.87% below the threshold value of 5%.

Conclusion(s): Calibration of INR with patient plasmas treated with Rivaroxaban allowed harmonizing
results and to reduce the variations between different thromboplastins.
INR Rivaroxaban is an inexpensive and routinely feasible test that can be a reliable test for monitoring patients treated with Rivaroxaban.