The effect of hydroxyethyl starch 200 kD on platelet function

We evaluated the effects of hydroxyethyl starch with a molecular weight of 200 kD (HES 200 kD) on platelets to gain insight into the potential mechani sms involved in the anticoagulant effects of HES 200 kD. Blood was obtained before and after an IV infusion (10 mL/kg) of either saline (n = 15) or HE S 200 kD (n = 15) in otherwise healthy patients scheduled for minor electiv e surgery. Flow cytometry was used to assess the expression of glycoprotein (GP) IIb-IIIa, GP Tb, and P-selectin on agonist-activated platelets. Overa ll platelet function was evaluated by assessing thromboelastographic maximu m amplitude (MA) in celite-activated blood and platelet function analyzer-c losure times by using collagen/adenosine diphosphate cartridges. Saline inf usion had no effects on platelet variables, whereas HES 200 kD reduced GP I Ib-IIIa expression and MA and prolonged platelet function analyzer-closure times, without affecting the expression of P-selectin and GP Ib. In vitro e xperiments extended these observations by a concentration-related inhibitin g effect of HES 200 kD on GP IIb-IIIa expression. This study demonstrates t hat cellular abnormalities with decreased availability of platelet GP IIb-I IIa are involved in the anticoagulant effects of HES 200 kD.