Evaluation of agreement of placental growth factor (PlGF) tests and the soluble FMS-like tyrosine kinase 1 (sFlt-1)/PlGF ratio, comparison of predictive accuracy for pre-eclampsia, and relation to uterine artery Doppler and response to aspirin

Abstract

Objectives: The objective of this study is to evaluate agreement between PlGF and sFlt-1/PlGF ratio tests and compare their predictive accuracy for pre-eclampsia in high-risk women. Also, to examine for associations of abnormal PlGF or sFlt-1/PlGF ratio with abnormal uterine artery Doppler and platelet response to aspirin.

Methods: Prospective cohort study, 150 pregnant women at high risk of pre-eclampsia prescribed 75 mg aspirin daily. Uterine artery Dopplers were assessed at 20⁺⁰–23⁺⁶ weeks. At 33⁺⁰–35⁺⁶ weeks platelet function aspirin metabolites, PlGF and the sFlt-1/PlGF ratio were measured.

Outcome: Measures were all pre-eclampsia and pre-eclampsia requiring delivery prior to 37 weeks.

Results: Overall percent agreement was 89.3% for PlGF tests but 74.7–78% for PlGF tests and the sFlt-1/PlGF ratio. AUCs were 0.70–0.75 for prediction of any pre-eclampsia and 0.92–0.99 for preterm pre-eclampsia. We found a significant association between abnormal PlGF or sFlt-1/PlGF ratio and abnormal uterine artery Doppler (χ² 5.47, p = .019), but no association with platelet response to aspirin (χ² 0.12, p = .913). There were no associations between suboptimal aspirin adherence and either abnormal angiogenic markers or uterine artery Dopplers (χ² 0.144, 0.038, p = .704, .846, respectively).

Conclusions: There was good agreement between PlGF tests and limited agreement between PlGF tests and the sFlt-1/PlGF ratio. All tests have heightened predictive accuracy for preterm pre-eclampsia. Abnormal PlGF or sFlt-1/PlGF ratio relates to abnormal uterine artery Doppler but not platelet response to aspirin.

Keywords:

• Aspirin
• PlGF
• pre-eclampsia
• sFlt-1/PlGF ratio

Acknowledgements

The authors thank Wellbeing of Women who provided a Research Training Fellowship for Dr Kate Navaratnam.

Disclosure statement

Roche Diagnostics Limited provided the sFlt-1 kits for this analysis free of charge. Roche did not influence the conduct of the study, analyses or content of the manuscripts.

Additional information

Funding

This work was supported by Wellbeing of Women [RTF 403].