The additive role of angiogenic markers for women with confirmed preeclampsia.

BACKGROUND

Hypertension complicates 2% to 8% of all pregnancies and is a leading cause of maternal and perinatal morbidity and mortality globally. Given the prognostic role that angiogenic markers play in evaluation of patients with "suspected preeclampsia," the International Society for the Study of Hypertension in Pregnancy incorporated angiogenic imbalance into the 2021 definition of preeclampsia. As women with "suspected preeclampsia" are a heterogeneous group, with some already meeting the diagnostic criteria for preeclampsia, we evaluated whether the soluble fms-like tyrosine kinase-1/placental growth factor ratio adds prognostic value among these women.

OBJECTIVE

This study aimed to assess the additive value of soluble fms-like tyrosine kinase-1/placental growth factor ratio when the diagnostic criteria for preeclampsia have already been met.

STUDY DESIGN

This was a secondary analysis of a prospective cohort study of patients presenting to obstetrical triage with suspected preeclampsia at ≥20 weeks' gestation from July 2009 to June 2012 in Boston, United States. Clinicians were masked to soluble fms-like tyrosine kinase-1/placental growth factor ratio results. Clinical records were reviewed for maternal and neonatal care and outcomes. The value of the soluble fms-like tyrosine kinase-1/placental growth factor ratio (≤38, >38, or >85) was assessed for identifying women at low or high risk of evolving into preeclampsia with severe features within 2 weeks of the triage visit, with preeclampsia with severe features being defined by the American College of Obstetricians and Gynecologists (2013 definition). Based on information in obstetrical triage, preeclampsia among triage patients was defined either by: (1) The International Society for the Study of Hypertension in Pregnancy "restrictive" criteria (ie, new-onset hypertension and proteinuria at ≥20 weeks), or (2) The International Society for the Study of Hypertension in Pregnancy "broad" maternal criteria (ie, new-onset hypertension with proteinuria or one/more relevant maternal end-organ complications).

RESULTS

Of 1043 patients included, 459 presented at 20 to 34 weeks and 584 at ≥35 weeks. In triage, 25.8% of women with "suspected preeclampsia" already met the preeclampsia criteria based on the International Society for the Study of Hypertension in Pregnancy broad criteria and 22.0% based on the restrictive criteria. In separate multivariable analyses adjusted for gestational age, a soluble fms-like tyrosine kinase-1/placental growth factor ratio >38 was independently associated with preeclampsia with severe features within 2 weeks even after adjusting for preeclampsia diagnosis in obstetrical triage, whether that preeclampsia were defined restrictively (odds ratio, 15.62; 95% confidence interval, 8.91-27.40) or broadly (odds ratio, 14.56; 95% confidence interval, 8.30-25.56). A soluble fms-like tyrosine kinase-1/placental growth factor ratio ≤38 was good at ruling out development of preeclampsia with severe features within 2 weeks among all patients and among those meeting the restrictive or broad definitions of preeclampsia (negative likelihood ratios, ≤0.16), driven by performance of the ratio before 35 weeks (ie, negative likelihood ratio ≤0.12). A soluble fms-like tyrosine kinase-1/placental growth factor ratio >85 was good at ruling-in preeclampsia with severe features within 2 weeks among women with suspected preeclampsia, either before (positive likelihood ratio, 8.20) or after 35 weeks (positive likelihood ratio, 6.00) and fair at ruling-in preeclampsia with severe features within 2 weeks when preeclampsia had already been confirmed in patients at <35 weeks (restrictively positive likelihood ratio, 3.48, or broadly positive likelihood ratio, 3.40).

CONCLUSION

Our findings support the prognostic value of the soluble fms-like tyrosine kinase-1/placental growth factor ratio among patients with confirmed preeclampsia, particularly to identify those both likely and unlikely to progress toward the development of severe features in the next 2 weeks and those who may be most appropriate for expectant and potentially outpatient care. Our findings support the incorporation of angiogenic imbalance into the definition of preeclampsia, particularly at 20-34 weeks.