Introduction
Hypertensive pregnancy diseases affect up to 10 % of all pregnancies worldwide.1,2 Among them are preeclampsia, characterized by hypertension and proteinuria as well as HELLP syndrome, a multisystemic disorder, defined by haemolysis, elevated liver enzymes and low platelet count.3 The HELLP syndrome shares a variety of features with other liver diseases, which compromise approximately 3% of all pregnancies worldwide.4 Acute fatty liver of pregnancy (AFLP) is a rare but often devastating disease with an incidence that varies between 1:7000 and 1:20’000 pregnancies.5 AFLP and HELLP syndrome share multiple clinical symptoms and up to date for both clinical conditions delivery remains the only treatment. Some clinical approaches recommend immediate delivery in AFLP whereas in HELLP syndrome delivery can be delayed, in particularly before 34 gestational weeks to assure fetal lung maturation following corticoid administration. 6-8 Compared to HELLP syndrome AFLP, however, carries an even higher risk of adverse maternal and fetal outcome.9 Patients affected by HELLP syndrome with or without preeclampsia and those compromised by AFLP share - apart from clinical features - also common laboratory findings such as thrombocytopenia, haemolysis and especially elevated liver enzymes.10 A prerequisite for prompt diagnosis is a robust diagnostic tool to differentiate between these liver-associated pregnancy complications with clinical and laboratory overlapping features.
The gold standard for the diagnosis of AFLP is histological confirmation following liver biopsy. These interventions, however, are rarely performed due to the risk of haemorrhages and the urgent need to deliver affected patients. Therefore, non-invasive Swansea criteria have been proposed to identify patients with AFLP.5, 11 In a large population-based prospective study, Knight et al have shown that six or more Swansea criteria reasonably well agreed with the clinical diagnosis.
Angiogenic factors play an important role in the pathogenesis of placenta-associated complications such as preeclampsia with and without HELLP syndrome.12 Angiogenic profiling using sFlt-1/PLGF ratio can be helpful to identify women with impending preeclampsia and these markers have also the potential to tailor the management in women with established preesclampsia although this point is still controversial.13-15 The data on angiogenic factors in AFLP is scarce. Initial studies investigating the angiogenic status in AFLP patients assume that the anti-angiogenic condition aggravates compared to patients with HELLP syndrome.16, 17
The aim of this study was to analyse the angiogenic profile in pregnancies compromised by AFLP and to assess whether angiogenic factors may be useful to discriminate between AFLP and HELLP syndrome.