Background:
Preeclampsia (PE), which almost occurs on the basis of hypertension
(≥140/90mmHg on 2 separate occasions of at least 4 hours apart) in
pregnancy, affects 2-8% of pregnancies and constitutes one of the major
causes of maternal and perinatal mortality globally[1]. In China,
the rate of still birth in the women with PE and eclampsia increased
4-fold compared to normotensive pregnancies[2]. Early prediction of
PE remains a challenge in clinical practice.
The pathogenesis of PE is thought to involve insufficient placental
perfusion resulting from the lack of trophoblast invasion and remodeling
of spiral arteries at early stage of pregnancy[3], in which the
soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor
(PlGF) were found to be important mediators. As the antagonist of PlGF,
the imbalance of sFlt-1 and PlGF, might lead to vasoconstriction and
endothelial dysfunction of placenta formation and subsequent symptoms of
PE [4]. The predictive value of sFlt-1/PlGF ratios for PE has been
previously researched in general population.. Verlohren et al.
established the cutoffs of sFlt-1/PlGF ratio ≤34 to rule out PE
occurrence, while sFlt-1/PlGF ratio ≥85 and ≥110 to rule out PE
occurrence at <34 and ≥34 weeks of gestation,
respectively[5]. More recently, Zeilser et al. verificated that the
ratios of sFlt-1/PlGF at 38 or below had superior negative predictive
value on PE among symptomatic European patients and the cutoff was
replicated in Asian population across 25 centers[6].
At present, the Elecsys immunoassay (Roche Diagnosis) has been accpted
as the standard assay for sFlt-1 and PlGF in the early prediction of PE
in many Obstetrics centers, in which the applicable population were
normal pregnancies [7]. While PE is almost always subsequent to
hypertensive manifestations. In the latest guidelines for HDP
(hypertension in pregnancy), the diagnosis of PE could be established by
hypertension in conjugation with other end-organ dysfunctions in the
absence of proteinuria[8]. Studies have shown that 40-50% of women
with hypertensive symptoms, regardless gestational or chronic, will
develop proteinuria or other end-organ damages that meet the criteria
for PE [9]. In the absence of reliable indicators, a large number of
hypertensive patients in pregnancy often need to be hospitalized to rule
out PE, while some may be ignored and develop severe PE features in a
short period of time [10]. As sFlt-1/PlGF has shown excellent
predictive value for PE in normal pregnancy, it is also of clinical
significance to explore the application of this ratio to predict PE in
pregnant women when abnormal BP is present.
The objective of this study is to evaluate the predictive performance
and optimal Kryptor specific threshold value for sFlt-1/PlGF ratios on
PE among the hypertensive pregnant women, including gestational
hypertension and chronic hypertension, in order to improve prognosis and
intervention for these patients in future.