von Willebrand Factor and Factor VIII Clearance in Perioperative Hemophilia A Patients

Authors: van Moort, I, Bukkems, LH, Heijdra, JM, Schutgens, REG, Laros-van Gorkom, BAP, Nieuwenhuizen, L, van der Meer, FJM, Fijnvandraat, K, Ypma, P, and de Maat, MPM.

Publication: Thrombosis and Haemostasis; June 2020

Affiliations: Department of Pediatric Hematology, Erasmus University Medical Center – Sophia Children’s Hospital, Rotterdam, The Netherlands ; Department of Clinical Pharmacology – Hospital Pharmacy, Amsterdam University Medical Center, Amsterdam, The Netherlands

Abstract: BACKGROUND: von Willebrand factor (VWF) is crucial for optimal dosing of factor VIII (FVIII) concentrate in hemophilia A patients as it protects FVIII from premature clearance. To date, it is unknown how VWF behaves and what its impact is on FVIII clearance in the perioperative setting. AIM: To investigate VWF kinetics (VWF antigen [VWF:Ag]), VWF glycoprotein Ib binding (VWF:GPIbM), and VWF propeptide (VWFpp) in severe and moderate perioperative hemophilia A patients included in the randomized controlled perioperative OPTI-CLOT trial. METHODS: A linear mixed effect modeling was applied to analyze VWF kinetics. One-way and two-way analyses of variance were used to investigate perioperative VWFpp/VWF:Ag ratios and associations with surgical bleeding. RESULTS: Fifty-nine patients with median age of 48.8 years (interquartile range: 34.8-60.0) were included. VWF:Ag and VWF:GPIbM increased significantly postoperatively. Blood type non-O or medium risk surgery were associated with higher VWF:Ag and VWF:GPIbM levels compared with blood type O and low risk surgery. VWFpp/VWF:Ag was significantly higher immediately after surgery than 32 to 57 hours after surgery (p < 0.001). Lowest VWF:Ag quartile (0.43-0.92 IU/mL) was associated with an increase of FVIII concentrate clearance of 26 mL/h (95% confidence interval: 2-50 mL/h) compared with highest VWF antigen quartile (1.70-3.84 IU/mL). VWF levels were not associated with perioperative bleeding F(4,227) = 0.54, p = 0.710. CONCLUSION: VWF:Ag and VWF:GPIbM levels increase postoperatively, most significantly in patients with blood type non-O or medium risk surgery. Lower VWF antigen levels did not lead to clinically relevant higher FVIII clearance. VWF:Ag or VWF:GPIbM levels were not associated with perioperative hemorrhage.