Effect of ABO blood group on haemostatic parameters in severe haemophilia A patients performing acute moderate-intensity exercise.

The primary objective was to assess the effect of ABO blood group on von Willebrand factor (VWF) rise induced by four bouts of moderate-intensity physical activity, on pharmacokinetics of a B-domain-deleted recombinant FVIII (BDD-rFVIII), and haemostatic parameters in severe haemophilia A patients with a null mutation. The secondary objective was to compare the response to exercise according to infused product type in a subgroup of patients who previously participated to the same exercise protocol, while treated with a full length recombinant FVIII (FL-rFVIII). Twenty patients had two visits (rest and exercise). Blood samples were drawn before administration of BDD-rFVIII and at 6 time points, until 24 h postinfusion. FVIII activity increased transiently by 1.1-fold, but only after the first exercise session, as compared to rest. VWF:Ag and platelet count were significantly elevated after each session. Mean FVIII half-life and thromboelastography measurements were unchanged with exercise. However, 14 participants had a slight variation of FVIII half-life with exercise compared to rest (from -3.42 h to +2.51 h). Seven patients demonstrated a longer FVIII half-life (four with O blood group), whereas the remainders had a reduced half-life three with O blood group). FVIII half-life correlated with baseline VWF: Ag at rest (r=0.70, P<0.001) and with exercise (r=0.67, P<0.002). Recovery was different between FL-rFVIII and BDD-rFVIII at rest (P=0.032), but no significant differences were observed between half-life of products at rest and with exercise. ABO blood group and the type of rFVIII administered did not influence the response to exercise. Copyright (C) 2018 Wolters Kluwer Health, Inc. All rights reserved.