[Perioperative prevention of thrombosis in cesarean section: results of a randomized prospective comparative study with 6% hydroxyethyl starch and 0.62 low dose heparin].

In 207 consecutive randomized women undergoing cesarean section, of whom 104 received 3 X 5000 IE unfractionated heparin and 103 3 X 500 ml hydroxyethylstarch 6% 0.62, the frequency of deep vein thrombosis was evaluated with a non-invasive diagnostic technique-impedance plethysmography. 5.9% of the patients in the hydroxyethylstarch group and 7.8% in the heparin-group developed deep vein thrombosis. Activation of blood coagulation at cesarean section results in an increasing of factor VIIIR:Ag, Fibrinogen and Reptilase clotting time. Hydroxyethylstarch 6% 0.62 produces minor abnormalities of coagulation test results. After 1500 ml infusions HES the following effects were noted: 1. Factor VIIIR:Ag fell by about 20%, a greater decrease than could be explained simply by hemodilution. 2. Reptilase clotting times shortened without a different increase in fibrin activation products (resulting in an increased lysability of the thrombus). 3. Plasma fibrinogen decreased by approximately 7% due to hemodilution caused by plasma volume expansion. For patients with a low risk of deep vein thrombosis (Cesarean section) HES has an excellent safety record in doses not exceeding 1500 ml/24 h.