Similarities in thromboelastometric (ROTEM®) findings between humans and baboons.

INTRODUCTION

Interest in visco-elastic testing in different clinical scenarios has increased but few data are available on thromboelastometric findings in primates.

MATERIALS AND METHODS

Blood cell count (hemoglobin, hematocrit, platelet count), coagulation parameters (prothrombin time, International Normalized Ratio, fibrinogen), and ROTEM® (Tem International GmbH, Munich, Germany) variables were analyzed using blood from 25 anesthetized male baboons and 21 non-anesthetized healthy volunteers. The platelet component of the clot was calculated as the difference in maximum clot elasticity (MCE) between the whole blood clot (EXTEM test) and the fibrin-based clot (FIBTEM test). In subgroups of each species, 10 μg abciximab was added to the regular FIBTEM reagent (cytochalasin D) for additional platelet inhibition.

RESULTS

Blood cell count was comparable between humans and primates. Both fibrinogen concentration (p<0.0001) and maximum clot firmness (MCF) in FIBTEM assays were significantly lower in baboons (p>0.0001, and p=0.006, respectively). PT, INR, and clotting time in NATEM assays were significantly prolonged in humans compared with baboons. MCF in NATEM, EXTEM and INTEM assays was not different between baboons and humans. Clot lysis in NATEM, EXTEM and INTEM assays was significantly higher in humans (p<0.0001). In contrast FIBTEM clot lysis was significantly higher in baboons (p=0.01). Addition of abciximab into the FIBTEM assay resulted in a significant reduction in MCF and MCE (p<0.001) and, consequently, the platelet component increased similar in both humans and baboons (p<0.001).

CONCLUSION

Activated ROTEM® tests revealed broad similarities between humans and baboons. ROTEM® assays developed for use in humans can also be used in baboons.