Decreased circulating levels of von Willebrand factor after intravenous administration of a rapidly degradable hydroxyethyl starch (HES 200/0.5/6) in healthy human subjects

Objective: Impairment of haemostasis has been described with slowly degradable medium molecular weight hydroxyethyl starch (MMW-HES), whereas rapidly degradable MMW-HES is generally considered to have no important effects on blood coagulation. This study was undertaken to investigate the effects of a rapidly degradable MMW-HES plasma substitute on primary haemostasis and blood coagulation in human subjects. Design: Randomised, cross-over study. Setting: Research unit of a university hospital. Participants: Nine healthy, adult male volunteers. Interventions: A 60-min intravenous infusion of 1 1 HES 200/0.5/6 (HAES-steril 6 %) or 4 % albumin (control). Measurement and results: The infusion of HES resulted in decreased circulating levels of von Willebrand factor antigen (from 85 +/- 8 % to 59 +/- 6 % after HES vs from 80 +/- 7 % to 69 +/- 8 % after albumin, p < 0.05) and ristocetin cofactor activity (from 93 +/- 4 to 67 +/- 4 % after HES vs from 79 +/- 5 to 75 +/- 5 % after albumin, p < 0.01). This was associated with an impairment of in vitro platelet function as determined with the PFA-100 platelet function analyser (closure time with collagen/epinephrine from 120 +/- 7 to 159 +/- 14 s after HES vs from 121 +/- 7 to 137 +/- 10 s after albumin, p < 0.05; with collagen/ADP from 88 +/- 3 to 116 +/- 9 s and from 103 +/- 4 to 114 +/- 7 s after HES and albumin, respectively, p = 0.01). Conclusions: The infusion of 11 of HES 200/0.5/6 in healthy human subjects results in moderately decreased plasma levels of von Willebrand factor associated with impairment of platelet function.