Can the laboratory assay of protein C activity assist in monitoring the hemostatic function in pre-eclampsia?

Published reports do not agree about whether protein C activity is non-sign ificantly changed or decreased in a hypercoagulable state induced by pre-ec lampsia without hemoloysis-elevated liver enzyme/low platelet (HELLP) syndr ome. In order to assess the relationship between this anticoagulant and enh anced hemostasis, levels of protein C activity, thrombin-antithrombin compl exes, soluble fibrin, fibrin D-dimers and antithrombin were determined in 3 0 pre-eclampsia patients without the HELLP syndrome, in 22 normal pregnant women in gestational weeks 30-35, and in 13 non-pregnant controls. Levels o f thrombin-antithrombin complexes, soluble fibrin and D-dimers increased (P < 0.05) whereas antithrombin decreased (P < 0.05) in patients with preecla mpsia, compared with normal pregnant women. Levels of protein C did not dif fer significantly between patients with preeclampsia, normal pregnant women and controls (P > 0.05). The 5th and 95th percentiles of protein C levels in normal pregnant women were 0.53 and 1.30 U/ml, respectively; levels betw een these two values could be considered physiological. When the preeclamps ia patients were subdivided according to these percentiles, none belonged t o the subgroup with protein C less than or equal to 5th percentile; 230% (s even of 30) fell into the subgroup with protein C greater than or equal to 95th percentile. Elevated levels of hypercoagulation markers were shown in the groups whose protein C fell within 5th-95th or greater than or equal to 95th percentiles (P < 0.05), compared with normal pregnant women. Concentr ations of protein C and thrombin-antithrombin complex were significantly co rrelated (r = 0.69, P > 0.05) in patients with pre-eclampsia. In summary, i n subjects with pre-eclampsia without the HELLP syndrome, protein C activit y may be similar to that in normal pregnant women. However, such a 'physiol ogical' anticoagulant level in association with the enhanced thrombin gener ation and fibrin formation does not necessarily reflect a physiological cap ability of coagulation. Thus, assays of protein C activity might not always assist in monitoring the hemostatic function during pre-eclamptic pregnanc y. Blood Coag Fibrinol 10:127-132 (C) 1999 Lippincott Williams & Wilkins.