Angiogenic imbalance in pre-eclampsia and fetal growth restriction: enhanced soluble fms-like tyrosine kinase-1 binding or diminished production of placental growth factor?

OBJECTIVES

To assess levels of total placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and free PlGF in women with pre-eclampsia (PE) with or without a small-for-gestational-age (SGA) neonate in order to establish whether low free PlGF levels associated with PE and SGA are due to enhanced sFlt-1 binding or decreased PlGF production.

METHODS

This was a secondary analysis of a prospective multicenter cohort study involving 407 pregnancies with suspected or confirmed PE, in which total PlGF levels were calculated from measured sFlt-1 and free PlGF levels. The control group included women who were suspected to have PE at a certain point in pregnancy but did not develop PE. The analysis was stratified according to whether PE was early- or late-onset (gestational age < 34 weeks vs ≥ 34 weeks) and according to the presence of SGA at birth, which was used as a proxy of fetal growth restriction in the absence of Doppler ultrasound and biometric data.

RESULTS

In early-onset PE, both women with and those without SGA had lower free (19 and 45 pg/mL) and total (44 and 100 pg/mL) PlGF levels compared with women without PE (free and total PlGF, 300 and 381 pg/mL, respectively). SGA alone did not affect free and total PlGF in this condition (free and total PlGF, 264 and 352 pg/mL, respectively). Observations in women with late-onset PE were similar, although the changes were more modest. Both SGA (gestational age < 34 weeks) and PE were individually associated with increased sFlt-1 and, in women with both PE and SGA, the upregulation of sFlt-1 occurred in a synergistic manner, thus resulting in the highest sFlt-1/free PlGF ratio in this group. This occurred in both early- and late-onset PE.

CONCLUSIONS

Particularly in pregnancies with early-onset PE and SGA, diminished PlGF production is an important cause of low free PlGF levels. Under such conditions, sFlt-1 lowering is unlikely to restore the angiogenic balance. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of pre-eclampsia-related complications in women with suspected or confirmed pre-eclampsia: development and internal validation of clinical prediction model

OBJECTIVE

A model that can predict reliably the risk of pre-eclampsia (PE)-related pregnancy complications does not exist. The aim of this study was to develop and validate internally a clinical prediction model to predict the risk of a composite outcome of PE-related maternal and fetal complications within 7, 14 and 30 days of testing in women with suspected or confirmed PE.

METHODS

The data for this study were derived from a prospective, multicenter, observational cohort study on women with a singleton pregnancy and suspected or confirmed PE at 20 to < 37 weeks' gestation. For the development of the prediction model, the possible contribution of clinical and standard laboratory variables, as well as the biomarkers soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF) and their ratio, in the prediction of a composite outcome of PE-related complications, consisting of maternal and fetal adverse events within 7, 14 and 30 days, was explored using multivariable competing-risks regression analysis. The discriminative ability of the model was assessed using the concordance (c-) statistic. A bootstrap validation procedure with 500 replications was used to correct the estimate of the prediction model performance for optimism and to compute a shrinkage factor for the regression coefficients to correct for overfitting.

RESULTS

Among 384 women with suspected or confirmed PE, 96 (25%) had an adverse PE-related outcome at any time after hospital admission. Important predictors of adverse PE-related outcome included sFlt-1/PlGF ratio, gestational age at the time of biomarker measurement and protein-to-creatinine ratio as continuous variables. The c-statistics (corrected for optimism) for developing a PE-related complication within 7, 14 and 30 days were 0.89, 0.88 and 0.87, respectively. There was limited overfitting, as indicated by a shrinkage factor of 0.91.

CONCLUSIONS

We propose a simple clinical prediction model with good discriminative performance to predict PE-related complications. Determination of its usefulness in clinical practice awaits further investigation and external validation. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

POS0542 DISEASE ACTIVITY IN PREGNANT WOMEN WITH RHEUMATOID ARTHRITIS: IMPACT ON THE SOLUBLE FMS-LIKE TYROSINE KINASE-1 TO PLACENTAL GROWTH FACTOR RATIO

Background:

An elevated sFlt-1 indicates soluble Fms-like tyrosine kinase-1 (sFlt-1)/ placental growth factor (PlGF) ratio has recently been validated as significant predictor of preeclampsia (PE)(1). However, raised sFlt-1 levels due to inflammation are observed in patients with rheumatoid arthritis (RA)(2). The use of the sFlt-1/PlGF ratio for the prediction of PE has not been evaluated in pregnant women with diseases that are characterized by high levels of inflammation, such as RA

Objectives:

We investigated whether sFlt-1 and/or PlGF are altered in pregnant women with RA according to disease activity, and evaluated whether a sFlt-1/PlGF ratio of ≤38 could be used to predict the absence of PE in pregnant RA-patients.

Methods:

This study was embedded in a nationwide, observational, prospective cohort study on pregnant women with RA (PARA-study). sFlt-1 and PlGF levels were measured, using automated analyzer (Cobas-6000, e-module; Roche-Diagnostics), in the third trimester of pregnancy.

Results:

A total of 221 women, aged 21–42 years, were included. Values of sFlt-1, PlGF and sFlt-1/PlGF ratio were not significantly correlated with the DAS28-CRP (Figure 1). CRP correlated weakly with PlGF (r=-0.14, p=0.03), while no correlation was found with sFlt-1 or the sFlt-1/PlGF ratio.

Preeclampsia occurred in four out of 214 women with a ratio ≤38 (2%) in contrast to three out of seven women with a ratio >38 (43%), p<0.001 (Table 1). When stratified to a sFlt-1/PlGF ratio of ≤38 only 2% of women developed preeclampsia, compared to 43% of the women with a ratio >38. The observed sensitivity and specificity for a sFlt-1/PlGF ratio cut-off of ≤38 were 42.1% and 98.1%, respectively, with a negative predictive value (NPV) of 98%. All women that developed PE, developed PE >4 weeks after collecting of blood samples in the 3rd trimester, therefore the observed NPV could be even higher.

Table 1.

Pregnancy Outcome according to sFlt-1/PlGF ratio with a cut-off value of 38.

ParameterRatio ≤38Ratio >38P-valueN2147GA at birth, weeks39 (38 - 40)37 (36 - 40)0.05<342 (1)0(0)1.0034 - 3718 (8)2 (29)0.12Male, n (%)113 (53)5 (71)0.45Birth weight, grams3420 (2998 - 3800)2620 (2360 - 2850)<0.01Maternal OutcomeGestational Hypertension15 (7)2 (29)0.09Preeclampsia4 (2)3 (43)<0.001Time to delivery, days66 (52 - 75)52 (44 - 66)0.08Fetal OutcomeBirth weight percentile <1033 (15)5 (71)<0.01Fetal/Neonatal Death1 (1)0 (0)1.00

Data are reported as median (interquartile range) or number (percentage). sFlt-1 indicates soluble Fms-like tyrosine kinase-1; PlGF, placental growth factor; GA, gestational age. Time to delivery is defined as the amount of days between blood sampling and delivery.

Conclusion:

Our study shows that in pregnant women with RA, the sFlt-1/PlGF ratio is not altered due to disease activity, and a cut-off of ≤38 of this ratio can be used to exclude preeclampsia.

References:

[1]H. Zeisler et al. Predictive Value of the sFlt-1:PlGF Ratio in Women with Suspected Preeclampsia. N Engl J Med 2016; 374: 13-22. DOI 10.1056/NEJMoa1414838.

[2]S. Ballara et al. Paleolog. Raised serum vascular endothelial growth factor levels are associated with destructive change in inflammatory arthritis. Arthritis Rheum 2001; 44: 2055-2064. DOI 10.1002/1529-0131(200109)44:9<2055::AID-ART355>3.0.CO;2-2.

Figure 1.

Correlations between sFlt-1, PlGF and sFlt-1/PlGF ratio with DAS28-CRP and CRP. Correlation coefficients for sFlt-1 (A-B), PlGF (C-D) and sFlt-1/PlGF ratio (E-F) with DAS28-CRP and CRP.

Acknowledgements:

The kits for measurement of sFlt-1/PlGF ratio were a kind gift from Roche Diagnostics, Germany. We thank all participants of the PARA study. Additionally, we extend our gratitude to the laboratory workers, in particular Nadine Davelaar and Priyanka Bangoer, and research assistants for their contribution to the data collection. We thank ReumaNederland (LLP project number: LLP-26) for their financial support.

Disclosure of Interests:

Hieronymus TW Smeele: None declared, R.I. Neuman: None declared, A.H.J. Danser: None declared, Radboud Dolhain Speakers bureau: Yes UCB, Roche, Abbvie, Genzyme, Novartis, Consultant of: Yes, Galapagos, Grant/research support from: Yes, UCB, W. Visser: None declared

Copeptin and mid-regional pro-atrial natriuretic peptide in women with suspected or confirmed pre-eclampsia: comparison with sFlt-1/PlGF ratio

OBJECTIVES

Arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) may contribute to the pathogenesis of pre-eclampsia (PE), but their role remains to be elucidated. Our aims were to evaluate the surrogates of AVP and ANP, C-terminal pro-AVP (copeptin) and mid-regional pro-ANP (MR-proANP), as biomarkers for the prediction of PE-related pregnancy complications and whether they are associated with angiogenic markers and/or clinical manifestations of PE.

METHODS

This was a retrospective analysis of a prospective cohort study that enrolled pregnant women with suspected or confirmed PE, between December 2013 and April 2016. From each patient, a blood sample was obtained at study entry and serum levels of copeptin, MR-proANP, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) were measured. We evaluated the ability of sFlt-1, PlGF, sFlt-1/PlGF ratio, copeptin and MR-proANP, assessed either alone or combined with traditional predictors (gestational age, parity, diastolic blood pressure and proteinuria), to predict maternal complications and fetal/neonatal complications. Models were compared using concordance statistic (C-index).

RESULTS

A total of 526 women were evaluated in the study. Women with confirmed PE displayed elevated serum copeptin and MR-proANP levels in comparison to those with suspected PE but no hypertensive disease of pregnancy. When combined with traditional predictors, the sFlt-1/PlGF ratio displayed a higher C-index than copeptin and MR-proANP (0.76, 0.63 and 0.67, respectively, vs 0.60 for the traditional predictors alone) for the prediction of maternal complications. Similarly, for the prediction of fetal/neonatal complications, the sFlt-1/PlGF ratio displayed a higher C-index than copeptin and MR-proANP when added to the traditional model (0.83, 0.79 and 0.80, respectively, vs 0.79 for the traditional predictors alone). When subdividing women according to sFlt-1/PlGF ratio (≥ 85 vs < 85), no differences in copeptin levels were observed, while MR-proANP level was elevated in women with sFlt-1/PlGF ratio ≥ 85. Multiple regression analysis revealed that copeptin and MR-proANP were independent determinants of proteinuria.

CONCLUSIONS

Copeptin and MR-proANP have limited value in predicting PE-related complications when compared with the sFlt-1/PlGF ratio. However, both copeptin and MR-proANP were associated with proteinuria, with copeptin exerting this effect independently of the sFlt-1/PlGF ratio. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.