Development and validation of a novel fetal vesico-amniotic shunt, the vortex shunt

Fetal lower urinary tract obstruction (LUTO) is a severe malformation associated with an up to 80% mortality risk as well as significant renal and pulmonary morbidity in survivors. Fetal vesico-amniotic shunts (VAS) bypass the bladder obstruction, improve amniotic fluid volume and enhance in-utero pulmonary development. VAS has been shown to reduce respiratory morbidity and mortality in the neonatal period without proven benefit on long-term renal and bladder function. Clinically available shunts are associated with an up to 80% dislodgement rate, leading to repeat invasive procedures which increase fetal and maternal risks. We developed a novel "Vortex" shunt, which incorporates enhanced fixation to reduce dislodgement, a one-way valve to optimize in-utero bladder function, and enhanced sonographic echogenicity that optimizes the accurate deployment. Following the validation of these characteristics in initial benchtop experiments we have moved to feasibility studies in the fetal lamb model. We hope that the Vortex shunt may ultimately facilitate shunt deployment, reduce dislodgement risk, improve neonatal morbidity and mortality, and decrease the significant healthcare expenditures associated with long-term morbidity in LUTO survivors. In this manuscript, we review the natural history of LUTO, the risks and benefits of clinically available fetal shunts, and our development and early validation experiments. What is already known about this topic?Fetal vesico-amniotic shunting (VAS) for lower urinary tract obstruction (LUTO) improves survival in selected cases, but the dislodgement risk with currently available shunts is significant.VAS has not been shown to improve neonatal renal outcomes, and end-stage renal disease (ESRD) is a significant risk among LUTO survivors.What does this study add?In-vitro testing shows that the novel Vortex vesico-amniotic shunt may facilitate placement, improve sonographic visualization, decrease dislodgement rate, improve kink resistance and allow for dynamic size adjustment compared to existing shunts.The Vortex shunt is the first fetal vesico-amniotic shunt with a one-way valve aimed at addressing dysfunctional bladder function.