P05.05: SFlt-1/PlGF ratio in clinical practice: reassessment of cut-off values for predicting pre-eclampsia in our cohort of patients

Pre-eclampsia (PE) is a major cause of maternal and perinatal morbidity. This condition is subdivided into early (<34 weeks) and late (after 34 weeks) PE. We found to have too high false positivity using previously published cut-off values (85 and 110 for Roche Elecsys) in our setting. The objective of this case-control study is to investigate potential value of maternal serum angiogenic factor ratio soluble fms-like tyrosine kinase-1 (sFlt-1) / placental growth factor (PlGF) in prediction of early and late PE in our institute. Serum s-Flt-1 and PlGF and their ratio pre-eclamptic index (PEI) were measured in a case-control study of patients that developed PE before or after 34 weeks and unaffected controls. Pre-eclampsia was defined by blood pressure > 140/90mmHg and proteinuria > 300mg/24h. We analysed s-Flt-1 and PlGF (Brahms Kryptor). PEI was calculated for patients before and after 34 weeks of pregnancy. We observed gestational age at delivery (GA), incidence of PE, HELLP syndrome, FGR, SGA, IUFD and perinatal outcomes. Statistical analysis was performed using IBM SPSS Statistics 24. Our study included 339 patients. Average maternal age was 32.9 years, average BMI 24.9, 43% was primigravids and 56% was nulliparous. Patients with subsequent adverse outcomes (n=87) had significantly higher sFlt-1, lower PlGF and higher PEI than women without adverse outcomes (n=252), p<0.001. PEI ratio correlated with prematurity. GA was significantly lower in the PE group: 34.7 vs 39.5 weeks, p<0.001. We calculated a cut-off for PEI ratio (>300) with good sensitivity and specificity for prediction of early PE. This cut-off shows good prediction value (AUC 0.86) for measurements by Brahms Kryptor. Our study shows that previously published PEI cut-off levels did not improve pre-eclampsia detection when measuring sFlt-1/PlGF ratio with Brahms Kryptor in our setting. We propose cut-off (PEI > 300) that shows high diagnostic accuracy for early PE. Further analysis is needed.