Clinical Experience and Major Learning Points Following the Implementation of the sFlt-1/PlGF Ratio in the Management of Suspected Preeclampsia in a South Australian Tertiary Hospital.

Abstract

Introduction: The ability to measure pro-angiogenic (PlGF) and anti-angiogenic (sFlt-1) factors, specifically the sFlt-1/PlGF ratio, allows obstetricians to assess syncytiotrophoblast stress, a key mechanism in preeclampsia. In Australia, the introduction of this ratio to clinical practice, particularly its high negative predictive value, was led by Professor Brennecke (Melbourne). At our tertiary centre, adapted Victorian guidelines were introduced in October 2021. Despite multiple educational sessions, the transition from assessing 'end organ damage' to the 'placental syndrome' presented challenges for clinicians.

Materials and methods: This retrospective audit examined 431 women over 20 months to assess the implementation of the sFlt-1/PlGF ratio. The primary objective was to identify key educational points to improve clinical decision-making and the accurate use of the ratio in a tertiary centre.

Results: Of 750 tests, 79% (n = 596) were ordered according to guidelines. Among 154 tests ordered outside the guidelines, 57% (n = 88) were performed within a reassuring time frame from the previous test, 41% (n = 63) outside validated gestational windows, 1% (n = 2) with an unknown indication and 1% (n = 1) following a 'severe risk' result.

Discussion: Common errors included repeating tests too frequently (despite the high negative predictive value over 3-4 weeks), testing prior to 20 weeks or after 37 weeks, and underestimating the prognostic value of very high sFlt-1/PlGF ratios.