Oral Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2018

Midpregnancy PlGF and sFlt1/PlGF ratio testing for the prediction of early onset preeclampsia – which test performs best in an Australian patient population? (#22)

Carin L Black 1 2 , Ahmed Al-Amin 3 4 , Daniel L Rolnik 5 6 , Caroline Stolarek 1 , Stefan C Kane 1 2 3 , Adrienne White 1 , Fabricio Costa 3 4 5 , Shaun Brennecke 1 2
  1. Department of Maternal-Fetal Medicine, The Royal Women's Hospital, Parkville, VIC, Australia
  2. Department of Obstetrics and Gynaecology, The Royal Women's Hospital, Parkville, VIC, Australia
  3. Pauline Gandel Imaging Centre, The Royal Women's Hospital, Parkville, VIC, Australia
  4. Monash Ultrasound for Women, Clayton, VIC, Australia
  5. Perinatal Services, Monash Medical Centre, Clayton, VIC, Australia
  6. Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia

AIM Placental biomarkers soluble Fms-like tyrosine kinase-1 (sFlt1) and placental growth factor (PlGF), when tested at midpregnancy, may be predictive of early onset (<34 weeks) preeclampsia1,2,3. We aimed to determine which of PlGF or the sFlt1/PlGF ratio in an Australian patient population displays greatest clinical utility for this purpose.

 

METHODS This prospective study in singleton pregnancies included women attending antenatal booking visits between 19 and 22 weeks gestation. Maternal characteristics and medical history were recorded. Maternal blood was tested for PlGF and the sFlt1/PlGF ratio. The outcome measured was early onset preeclampsia. The screening performance of PlGF and the sFlt1/PlGF ratio were evaluated using receiver operating characteristic (ROC) curves, with clinical characteristics calculated using selected cutoff values.

 

RESULTS 512 patients were included. Values for PlGF and the sFlt1/PlGF ratio were significantly lower in patients who developed early onset preeclampsia (P<0.05). PlGF in isolation was able to predict early onset PlGF with AUC 0.92, sensitivity 100%, specificity 77.8% and NPV 100%. Addition of sFlt1 as the sFlt1/PlGF ratio improved predictive performance, with AUC 0.97, sensitivity 100%, specificity 95.87% and NPV 100%. The false positive rate using the sFlt1/PlGF ratio was much lower than using PlGF alone, at 4.5% compared with 23.2%.

 

CONCLUSION sFlt1/PlGF ratio for the prediction of early onset preeclampsia displays superior performance over use of PlGF alone, with significantly fewer false positive results. This test requires few resources to perform and is potentially feasible for a broad range of healthcare settings. Accurate midpregnancy detection of patients deemed high risk for early onset preeclampsia would allow streamlining of antenatal care, with close surveillance offered between 24 and 34 weeks for those deemed high risk for early onset preeclampsia and provision of reassurance for patients with a low risk screening result4. The long window between a positive test result and onset of symptoms would allow targeted studies in high risk patients investigating potential prophylactic and therapeutic agents for this complex condition5.

 

REFERENCES

  1. Levine, R. J. Circulating Angiogenic Factors and the Risk of Preeclampsia. N Engl J Med 2004: 350(7): 672-83.
  2. Polliotti, B. M, Fry, A. G, Saller, D. N. et al. Second-trimester maternal serum placental growth factor and vascular endothelial growth factor for predicting severe, early-onset preeclampsia. Obstet Gynecol 2003: 101(6): 1266-74.
  3. Tjoa, M. L, van Vugt, J. M, Mulders, M. A. et al. Plasma placenta growth factor levels in midtrimester pregnancies. Obstet Gynecol 2001: 98(4): 600-7.
  4. Nicolaides, K. H. A model for a new pyramid of prenatal care based on the 11 to 13 weeks' assessment. Prenat Diagn 2011: 31(1): 3-6.
  5. Steegers, E. A, von Dadelszen, P, Duvekot, J. J. et al. Pre-eclampsia. Lancet 2010: 376(9741): 631-44.