O63. Removal of soluble Fms-like tyrosine kinase (sFlt-1) by plasma-specific apheresis: Pilot study in women with very preterm preeclampsia

Abstract

Background Preeclampsia is a devastating complication of pregnancy affecting both mother and fetus. Soluble Fms-like tyrosine kinase-1 (sFlt-1) is a potential therapeutic target in preeclampsia. We evaluated the safety and efficacy of treating women with very preterm preeclampsia using a plasma-specific dextran sulfate (PSDS) column to remove circulating sFlt-1. Methods This was an open study of up to three extra-corporeal PSDS-apheresis treatments in 10 women with very preterm preeclampsia to determine the extent of sFlt-1 and proteinuria reduction, and its safety for mother and fetus. Results Six patients with very preterm preeclampsia (mean gestational age 29 + 2 weeks) underwent one PSDS-apheresis treatment; three were treated twice, and one for three times. The apheresis volumes ranged from 400 to 1500 ml. Mean starting sFlt-1 concentration was 18,342 pg/mL (range 8243–35,301 pg/mL) with a 17% mean reduction per treatment (range 6–28%). Mean starting protein: creatinine (P/C) ratio was 6.4 g/g (range 0.4–16.9 g/g); mean reduction per treatment was 39% (range 88% reduction to 30% increase). Among women treated multiple times, pregnancy continued on average for 11 days (range 7–19 days). The most common side effect during treatment was transient blood pressure reduction ( ∼ 10–20 mmHg), managed by withholding antihypertensive therapies before treatment, saline prehydration, and reducing blood flow through the apheresis column. There were no adverse effects to fetuses or neonates. Conclusions Therapeutic apheresis reduces circulating sFlt-1 and proteinuria in women with very preterm preeclampsia, enabling pregnancy to continue. A controlled trial is needed to determine whether apheresis to remove sFlt-1 safely prolongs pregnancy.