Role of placental, fetal and maternal cardiovascular markers in predicting adverse outcome in women with suspected or confirmed pre-eclampsia

Objective: To assess the performance of placental, fetal and maternal cardiovascular markers in the prediction of adverse perinatal and maternal outcomes in women with suspected or confirmed pre-eclampsia. Methods: This was a prospective prognostic accuracy study of women with suspected or confirmed pre-eclampsia who underwent a series of investigations to measure maternal hemodynamic indices, mean arterial pressure, augmentation index, ophthalmic artery peak systolic velocity (PSV) ratio, uterine artery pulsatility index (UtA-PI), fetal biometric and Doppler parameters, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF). The performance of these markers, individually or in combination, in predicting adverse perinatal and maternal outcomes was then assessed using receiver-operating-characteristics (ROC)-curve analysis. Adverse maternal outcome was defined as one or more of severe hypertension, admission to the intensive care unit, eclampsia, placental abruption, HELLP syndrome, disseminated intravascular coagulation, platelets < 100 × 10⁹/L, creatinine > 90 μmol/L and alanine aminotransferase > 100 U/L. Adverse perinatal outcome was defined as one or more of preterm birth at or before 34 + 0 weeks, neonatal intensive care unit admission for > 48 h, respiratory distress syndrome, intraventricular hemorrhage, hypoxic ischemic encephalopathy, necrotizing enterocolitis, retinopathy of prematurity and confirmed fetal infection. Results: We recruited 126 women with suspected (n = 31) or confirmed (n = 95) pre-eclampsia at a median gestational age of 33.9 weeks (interquartile range, 30.9–36.3 weeks). Pregnancies with adverse perinatal outcome compared to those without had a higher median UtA-PI (1.3 vs 0.8; P < 0.001), ophthalmic artery PSV ratio (0.8 vs 0.7; P = 0.01) and umbilical artery PI percentile (82.0 vs 68.5; P < 0.01) and lower median estimated fetal weight percentile (4.0 vs 43.0; P < 0.001), abdominal circumference percentile (4.0 vs 63.0; P < 0.001), middle cerebral artery PI percentile (28.0 vs 58.5; P < 0.001) and cerebroplacental ratio percentile (18.0 vs 46.5; P < 0.001). Pregnancies with adverse perinatal outcome also had a higher median sFlt-1 (8208.0 pg/mL vs 4508.0 pg/mL; P < 0.001), lower PlGF (27.2 pg/mL vs 76.3 pg/mL; P < 0.001) and a higher sFlt-1/PlGF ratio (445.4 vs 74.4; P < 0.001). The best performing individual marker for predicting adverse perinatal outcome was the sFlt-1/PlGF ratio (area under the ROC curve (AUC), 0.87 (95% CI, 0.81–0.93)), followed by estimated fetal weight (AUC, 0.81 (95% CI, 0.73–0.89)). Women who experienced adverse maternal outcome had a higher median sFlt-1 level (7471.0 pg/mL vs 5131.0 pg/mL; P < 0.001) and sFlt-1/PlGF ratio (204.3 vs 93.3; P < 0.001) and a lower PlGF level (37.0 pg/mL vs 66.1 pg/mL; P = 0.01) and estimated fetal weight percentile (16.5 vs 37.0; P = 0.04). All markers performed poorly in predicting adverse maternal outcome, with sFlt-1 (AUC, 0.69 (95% CI, 0.60–0.79)) and sFlt-1/PlGF ratio (AUC, 0.69 (95% CI, 0.59–0.78)) demonstrating the best individual performance. The addition of cardiovascular, fetal or other placental indices to the sFlt-1/PlGF ratio did not improve the prediction of adverse maternal or perinatal outcomes. Conclusions: The sFlt-1/PlGF ratio performs well in predicting adverse perinatal outcomes but is a poor predictor of adverse maternal outcomes in women with suspected or diagnosed pre-eclampsia. The addition of cardiovascular or fetal indices to the model is unlikely to improve the prognostic performance of the sFlt-1/PlGF ratio.