Angiogenic markers and their longitudinal change for predicting adverse outcomes in pregnant women with chronic hypertension

Abstract

Background: Women with chronic hypertension are at increased risk for adverse maternal and perinatal outcomes. Maternal serum angiogenic markers, such as soluble fms-like tyrosine kinase 1 and placental growth factor, can be used to triage women with suspected preeclampsia. However, data about these markers in pregnant women with chronic hypertension are scarce.

Objective: We aimed to evaluate the predictive accuracy of maternal serum levels of soluble fms-like tyrosine kinase 1, placental growth factor, and their ratio for predicting adverse maternal and perinatal outcomes in women with chronic hypertension.

Study design: This was a retrospective analysis of prospectively collected data from January 2013 to October 2019 at the University of Vienna Hospital, Vienna, Austria. The inclusion criteria were pregnant women with chronic hypertension and suspected preeclampsia. The primary outcome of this study was the prognostic performance of angiogenic markers for the prediction of adverse maternal and perinatal outcomes in pregnant women with chronic hypertension. The accuracy of angiogenic markers for predicting adverse composite outcomes was assessed with a binomial logistic regression. The accuracy of each marker was assessed using receiver operating characteristics curves and area under the curve values. Area under the curve values were compared using De Long's test.

Results: Of the 145 included women with chronic hypertension and suspected superimposed preeclampsia, 26 (17.9%) women developed complications (ie, composite adverse maternal or fetal outcomes) within 1 week of assessment (average gestational age at assessment, 29.9 weeks) and 35 (24.1%) developed complications at any time (average gestational age at assessment, 30.1 weeks). In women who developed complications at any time, the median maternal serum soluble fms-like tyrosine kinase-1 to placental growth factor ratio was 149.4 (interquartile range, 64.6-457.4) compared with 8.0 (interquartile range, 3.37-41.2) for women who did not develop complications (P<.001). The area under the curve values for the maternal serum soluble fms-like tyrosine kinase-1 to placental growth factor ratio Z-score (0.95; 95% confidence interval, 0.90-0.99) and placental growth factor level Z-score (0.94; 95% confidence interval, 0.88-0.99) for predicting complications within 1 week of assessment were very high. The area under the curve values for new-onset edema (0.61; 95% confidence interval, 0.52-0.70), proteinuria (0.62; 95% confidence interval, 0.52-0.71), high mean arterial pressure (0.52; 95% confidence interval, 0.50-0.54), and other symptoms of preeclampsia (0.57; 95% confidence interval, 0.49-0.65) were all significantly lower than for the angiogenic markers (P<.001 for all). Women who had an angiogenic imbalance and/or proteinuria had the highest rate of complications (28/57, 49.1%). The rate of complications in women with an angiogenic imbalance and/or proteinuria was significantly higher than in women with either proteinuria, other symptoms, or intrauterine growth restriction in the absence of an angiogenic imbalance (49.1% vs 16.7%; P=.039). The highest positive and negative predictive values for predicting adverse outcomes were demonstrated by an angiogenic imbalance and/or proteinuria criteria with a positive predictive value of 49.1% (95% confidence interval, 50.4%-57.9%) and a negative predictive value of 92% (95% confidence interval, 85.5%-95.8%). Longitudinal changes in measurements of the gestational age-corrected ratio of soluble fms-like tyrosine kinase-1 to placental growth factor up to the last measurement had a significantly higher area under the curve value than the last measurement alone (area under the curve, 0.95; 95% confidence interval, 0.92-0.99 vs 0.87; 95% confidence interval, 0.79-0.95; P=.024) CONCLUSION: Maternal serum angiogenic markers are superior to clinical assessment in predicting adverse maternal and perinatal outcomes in pregnant women with chronic hypertension. Repeated measurements of the ratio of soluble fms-like tyrosine kinase-1 to placental growth factor seems beneficial given the better predictive accuracy compared with a single measurement alone. The use of angiogenic makers should be implemented in clinical management guidelines for pregnant women with chronic hypertension.

Keywords: adverse outcome; angiogenic markers; chronic hypertension; placental growth factor; prediction; preeclampsia; soluble fms-like tyrosine kinase-1.