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 l 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 1 l 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.