Angiogenic factors as diagnostic tests for preeclampsia: a performance comparison between two commercial immunoassays

Improving maternal and perinatal outcomes in the hypertensive disorders of pregnancy: a vision of a community-focused approach

The hypertensive disorders of pregnancy (HDP; pre-existing hypertension, gestational hypertension, and pre-eclampsia) remain important causes of maternal morbidity and mortality, especially in low- and middle-income countries. The paper summarizes the current state of evidence around possible technologies to support community-based improvements in maternal and perinatal outcomes for women with pre-eclampsia. Through the testing and, where proven, introduction of these technologies, we believe that HDP-related progress toward achieving Millennium Development Goal 5 can best be accelerated. The evidence and discussion are presented under the following headings: (1) prediction; (2) prevention; (3) diagnosis; (4) risk stratification; (5) decision aids; (6) treatment; (7) geographic information systems; (8) communication; and (9) community and patient education.

The promise of angiogenic markers for the early diagnosis and prediction of preeclampsia

BACKGROUND

An imbalance in circulating factors that regulate blood vessel formation and health, referred to as angiogenic factors, plays a central role in the pathogenesis of preeclampsia.

CONTENT

Several studies have demonstrated a strong association between altered circulating angiogenic factors and preeclampsia. These factors include circulating antiangiogenic proteins such as soluble fms-like tyrosine kinase 1 and soluble endoglin and proangiogenic protein such as placental growth factor. Abnormalities in these circulating angiogenic factors are not only present during clinical disease, but also antedate clinical signs and symptoms by several weeks. These alterations are particularly prominent in patients who present with preeclamptic signs and symptoms prematurely and/or in patients with severe preeclampsia. The availability of automated platforms for the rapid measurement of circulating angiogenic proteins in blood samples has now allowed researchers and clinicians to evaluate the utility of these assays in the diagnosis of the disease, in the stratification of patients in clinical trials, or in the monitoring of therapies. In this review we highlight the various studies that have been performed, with a focus on large validation studies.

SUMMARY

Measurement of circulating angiogenic proteins for the diagnosis and prediction of preeclampsia is still at an early stage but is rapidly evolving. Standardization across the various automated platforms and prospective studies that demonstrate clinical utility are needed.

Can placental growth factor in maternal circulation identify fetuses with placental intrauterine growth restriction?

OBJECTIVE

We investigated whether decreased concentrations of placental growth factor (PlGF) in maternal circulation differentiated placental intrauterine growth restriction (IUGR) from constitutionally small fetuses. Excluding congenital syndromes, infection, and aneuploidy, we assumed IUGR with an abnormal placental pathology to be of placental origin.

STUDY DESIGN

The study design included a single site, case-control study of 16 cases (9 placental IUGR, 7 constitutionally small) and 79 normal controls with singleton pregnancies. Plasma PlGF was measured by Triage PlGF immunoassay according to the product insert. A positive PlGF test was defined as a concentration less than the fifth percentile for gestational age for normal pregnancy.

RESULTS

A positive PlGF test was found in 9 of 9 placental IUGR cases, 1 of 7 constitutionally small fetuses, and 4 of 79 controls (P < .0001). PlGF identified placental IUGR from constitutionally small fetuses with 100% sensitivity and 86% specificity (P = .0009).

CONCLUSION

These preliminary data suggest PlGF may identify placental IUGR antenatally.

A single rapid point-of-care placental growth factor determination as an aid in the diagnosis of preeclampsia

OBJECTIVES

To evaluate the clinical performance of a rapid point-of-care test, Triage PLGF (Alere, San Diego) in the diagnosis of preeclampsia.

STUDY DESIGN

For the reference range 2212 plasma samples were collected from 595 subjects with normotensive pregnancies, between week 17 of gestation and delivery. In the case-control part, two cohorts of women with preeclampsia (80 women) were matched for maternal age, gestational age (GA) at sampling and parity with normotensive women who delivered at 37weeks or more.

RESULTS

The areas under the receiver operating characteristic curves (GA<35weeks) were 1.0 and 0.994 (cohort 1 and 2, respectively). The clinical sensitivity of the Triage PLGF test for the pooled GA range of 21⩽GA<35, using a GA dependent cut-off, was 1.0 for both cohorts with specificities of 1.0 and 0.940.

CONCLUSIONS

The Triage PLGF test distinguishes well between preterm pregnancies with and without preeclampsia.