Oral Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2023

Is the sFlt-PlGF ratio test useful in the prediction and diagnosis of pre-eclampsia in pregnant women with kidney transplants?   (#10)

Jessica Han 1 , Anna Krelle 2 , Alice Wookey 2 , Ciara McCormick 2 , Paul Champion de Crespigny 1 3 , Shaun Brennecke 2 4 , Julia Unterscheider 2 4
  1. Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
  2. Department of Maternal Fetal Medicine, Royal Women's Hospital, Melbourne, VIC, Australia
  3. Department of Nephrology, Royal Melbourne Hospital, Melbourne, VIC, Australia
  4. Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, VIC, Australia

Background: Pre-eclampsia in kidney transplant recipients may be difficult to diagnose due to overlapping clinical features such as hypertension and proteinuria. An elevated ratio of soluble fms-like tyrosine kinase 1 (sFlt-1) to placental growth factor (PlGF) is becoming increasingly recognised as an accurate diagnostic aid for pre-eclampsia (PET) (1). However, its role in pregnant kidney transplant recipients has not yet been established.

Aim: To investigate the use of sFlt/PlGF ratio testing in the diagnosis and prediction of PET in pregnant kidney transplant recipients.

Methods: We conducted a 5-year retrospective cohort study of pregnant kidney transplant recipients, who delivered after 20 weeks' gestation at the Royal Women's Hospital in Victoria, Australia, between 1st January 2018 and 31st December 2022. Patients were identified from the hospital database, and individual patient medical records were reviewed for completeness of data points.

Results: The study included 22 singleton pregnancies in 17 patients. The median maternal age at delivery was 33.0 (28-42) years. Over half of patients (59.1%, n=13) were nulliparous. The median interval from transplantation to delivery was 6 (2-17) years. 68.2% (n=15) of patients had pre-existing hypertension, 80% (n=12) of whom were on antihypertensives prior to pregnancy. None of the patients had pre-existing proteinuria.

Two-fifths of the patients in this cohort (40.9%, n=9) developed PET. 6 of these were classified as severe; 3 of these patients demonstrated concomitant fetal growth restriction  and 1 developed HELLP syndrome. sFlt/PlGF ratios were elevated in all patients diagnosed with severe PET, but remained within normal limits in the 3 patients diagnosed with mild PET instead. In the 59.1% (n=13) of patients who did not develop PET, sFlt/PlGF ratios were tested in 53.8% (n=7) of them and all were within normal limits.

The median gestational age at birth was 36.4 (20.0-40.4) weeks. Each patient had an median of 2.0 (1-11) tests across the duration of their pregnancy, the first at 30.5 weeks’ gestation (19.4-38.4) and the latest at 34.1 weeks’ gestation (24.1-36.4). 40.9% (n=9) of patients attempted vaginal birth, 22.2% (n=2) of whom proceeded to caesarean section, making the overall caesarean rate 68.2% (n=15). The live birth rate was 95.5% (n=21).

Conclusion: In this cohort of 22 pregnancies in patients with kidney transplant, the sFlt/PlGF ratio test was useful in the prediction and diagnosis of severe PET.

  1. Zeisler H, Llurba E, Chantraine F, Vatish M, Staff AC, Sennström M, et al. Predictive Value of the sFlt-1:PlGF Ratio in Women with Suspected Preeclampsia. N Engl J Med. 2016;374(1):13-22.