Summary
Microangiopathy and disseminated platelet aggregation have been reported in thrombotic
thrombocytopenic purpura (TIP) and pregnancy-induced hypertension (PIH). Since unusually
large von Willebrand factor (vWF) multimers have been implicated in the evolvement
of TTP, we analyzed factor VIII/vWF parameters in patients with PIH. Mean vWF: Ag
level was significantly higher in 27 patients with PIH as compared to 20 matched healthy
pregnant women (358 ± 160 u/dl vs. 274 ± 125 u/dl, p < 0.05). Moreover, plasma vWF:
Ag levels and the ratio of vWF: Ag to factor VIII were found to be linearly correlated
to the severity of PIH. In contrast, no significant differences in mean levels of
factor VIII and ristocetin cofactor were observed between these groups. Crossed immunoelectrophoresis
of vWF revealed a higher incidence of a pre-peak and an increased migration index
in the PIH group as compared to the control group (60% vs. 44% and 1.27 ± 0.26 vs.
1.19 ± 0.18, p < 0.01 respectively). Analysis of plasma vWF multimer patterns by 1.4%
agarose electrophoresis in 0.1% SDS revealed excessive amounts of large, medium and
small size multimers in the PIH patients. Conceivably, the quantitative changes in
vWF multimers reflect endothelial injury and may play a role in the microangiopathy
observed in PIH.
Keywords
Pregnancy-induced hypertension - Factor VIII - von Willebrand factor - Fetal growth
retardation
