A ROTEM method using APTT reagent and tissue factor as the clotting activators may better define bleeding heterogeneity in moderate or severe haemophilia A (part I: Study in plasma samples).Thromb Res 2018; 171:7-13TR
Bleeding heterogeneity observed in haemophilia A (HA) may attribute to that the available monitoring methods cannot appropriately reflect the coagulation profile. The present study aimed to develop a global approach by changing the clotting initiation way in rotational thromboelastometry (ROTEM) assay. ROTEM was run in Factor VIII (FVIII)-immune-depleted plasma to which different concentrations of recombinant VIII (rFVIII) had been added, and also in 31 patients with HA. The clotting activators were APTT reagent (1.2 × 10-3 of the dose used in the original APTT method) and recombinant tissue factor (0.02 pmol/L). In FVIII-immune-depleted plasma spiked with rFVIII, maximum velocity of coagulation reliably mirrored the rFVIII levels. This dose-response disappeared after the samples were pre-incubated with an antibody against TFPI, protein S, activated prothrombin complex concentrate or rFVIIa known to favour the extrinsic activation. In the HA patients with FVIII 0-0.21 IU/mL, APTT and ROTEM outcomes varied in significant correlations to FVIII activity; however, this correlation became non-significant when only samples with FVIII 0-0.05 IU/mL were included.