PB0491 - Patients from different settings receiving unfractionated heparin (DEXHEP study): impact of PF4 on anti-Xa levels

Sunday, June 25, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Philippe Savard, MD (he/him/his)

MedD
Hématologie Biologique, CHU, Dijon Bourgogne
Dijon, Bourgogne, France

Co-Author(s)

EC

Emmanuel Curis

PHD
UR 7537 BioSTM (Biostatistics), Université Paris Cité, Faculté de Pharmacie, Paris, France
Paris, Ile-de-France, France
Isabelle Gouin-Thibault, Sr., PhD

Head of hemostasis department
Department of Hematology/Hemostasis, Pontchaillou University Hospital of Rennes, Univ Rennes, Irset - Inserm UMR_S 1085, Rennes, France.
Rennes, Bretagne, France
MT

Marie Toussaint-Hacquard

PharmD-PHD
Hématologie Biologique, CHRU, Nancy
Nancy, Lorraine, France
CD

Céline Delassasseigne

PharmD
Laboratoire Hématologie, Hôpital Haut-Lévêque, CHU Bordeaux, France
Bordeaux, Aquitaine, France
AB

Anne Bauters

PharmD
Hematologie Biologique, CHU Lille, France
Lille, Nord-Pas-de-Calais, France
CF

Claire Flaujac

PharmD
Laboratoire de Biologie Médicale (Secteur Hémostase), Centre Hospitalier de Versailles, André Mignot, Le Chesnay, France
Versailles, Ile-de-France, France
VE

Valérie Eschewege

PharmD-PHD
Hématologie Biologique, CHRU Nancy, Nancy, France
Nancy, Lorraine, France
CM

Christine Mouton

PharmD
Laboratoire Hématologie, Hôpital Haut-Lévêque, CHU Bordeaux, France
Bordeaux, Aquitaine, France
TL

Thomas Lecompte

Professor
Université de Lorraine, Nancy, France
Nancy, Lorraine, France
ED

Emmanuel De Maistre

MD
Hématologie Biologique, CHU, Dijon
Dijon, Bourgogne, France
DL

Dominique Lasne

MedD-PHD
AP-HP, Laboratoire d’hématologie générale, Hôpital Necker, F-75015 Paris, France
Paris, Ile-de-France, France
VS

Virginie Siguret, PhD, PharmD

PharmD PhD, Professor in Hematology
INSERM UMR-S-1140, Innovative therapies in Haemostasis, Université Paris Cité, Paris
Paris, Ile-de-France, France

Background: In the DEXHEP study including 165 patients receiving unfractionated heparin (UFH), we reported that anti-Xa levels were higher when using a reagent containing dextran sulphate (DS) versus no DS. DS dissociates UFH/neutralizing protein (such as PF4) complexes. However, the impact of PF4 on the variability of anti-Xa levels measured with or without DS and using CTAD or citrate collection tubes is not known.

Aims: To measure PF4 concentrations in citrate and CTAD samples from patients in different clinical settings receiving UFH and to assess the association between anti-Xa and PF4 levels.

Methods: Blood was collected into citrated and CTAD tubes in four groups of patients. Anti-Xa assays were performed with seven assay/analyser combinations. PF4 levels were measured with ZymutestTM PF4 (Hyphen-Biomed) kit.

Results: Citrated and CTAD samples from 144 patients were analysed. PF4 levels were higher in citrated samples (+351% [+301;+406], p< 0.0001) (Figure1), despite short preanalytical time-periods (88% of blood centrifuged within 2h).
Pneumatic transportation increased PF4 levels, with a greater effect in CTAD tubes (+87%, p< 0.0001) than in citrated tubes (+32%, p=0.003). However, its effect on anti-Xa levels is less stringent and depends on the patients group.
In CTAD samples, anti-Xa levels were higher (+15%, p=0.005) than in citrated samples.
The difference of anti-Xa levels between citrate and CTAD tended to be higher when the differences of PF4 concentrations increased (beyond around 200ng/mL) (Figure2). The difference was observed with all commercially available reagents used regardless the presence or not of DS.

Conclusion(s): CTAD minimizes but might not be sufficient to fully prevent ex-vivo PF4 release. The PF4 release is increased by pneumatic transportation. The presence of PF4 may affect anti-Xa levels but does not totally explain the differences of anti-Xa levels observed with or without DS. The reason for higher anti-Xa levels obtained with DS reagents still needs further explorations.