Abstract

Background: Anti-angiogenic factors, including sFlt1, which is an alternatively splice variant
of vascular endothelial growth factor receptor1, have been implicated in the pathogenesis of
preeclampsia (PE). This is a serious health burden, which results in significant foeto-maternal
morbidity and mortality. sFlt1 binds and removes the pro-angiogenic factors like, placental
growth factor (PlGF) and vascular endothelial growth factor (VEGF) from the circulation, thus
leading to maternal systemic endothelial dysfunction and PE. sFlt1 and other angiogenic
proteins have been evaluated to play a central role in the diagnosis and prediction of PE in
pregnant women. This study explored the clinical utility of soluble fms-like tyrosine kinase
type1 (sFlt1) in the diagnosis and prediction of PE in high risk pregnant women.
Method: It was a prospective study involving ninety-seven participants with a high risk for
PE and ninety-seven controls. They were enrolled in the Obstetrics Clinics of Lagos University
Teaching Hospital, Island Maternity Hospital and Randle General Hospital and followed up for
seven months from June, 2016 to January, 2017. Blood samples were collected twice at 15
19+6 gestation and 24+3 – 36 gestational age. Their paired sera were analyzed for sFlt1 (using
ELISA kits). ALT, uric acid and urine protein: creatinine ratio were also assayed in their sera
and urine samples, respectively.
Results: There was no statistical significant difference in the ROC curve of sFlt1 below 20
weeks gestation with AUC of 0.590, sensitivity of 59.3%, specificity of 59.7%, at a cut-off of
1013pg/ml; PPV of 56%, NPV of 62.7%. However, the percentage change in median sFlt1
concentrations over the gestational ages between 15-19+6 and 24+3–36 was significant (%
∆=197.3). In contrast, the ROC of sFlt1 after 20 weeks gestation was statistically significant
with AUC of 0.949, sensitivity of 90.7%, specificity of 88.7% at a cut-off of 2660.9pg/ml;

PPV of 87.5% and NPV of 91.6%. sFlt1 also had a strong positive correlation with urine PCR
and BP and positive correlation with uric acid and ALT.
Conclusion: Abnormal placentation is known to occur early in the first trimester, sFlt1
concentrations in this trimester did not show any significant differences in at risk pregnant
women, who later developed PE, compared with the controls. Thus, sFlt1 rather appears to
confirm and not predict PE as found in this study.