LAUSR

Despite decades of technique refinement of transarterial embolization and the establishment of specialty referral centers, fetuses diagnosed with vein of Galen malformation continue to have high mortality, with survivors facing high rates of severe neurological and cognitive morbidity.1 Low resistance in the vein of Galen malformation arteriovenous shunt induces highflow physiology that compromises cerebral perfusion and induces cardiopulmonary stress. In utero, the placental circulation is also low resistance, providing compensation and fetal protection. Thus, most infants suffer decompensation postnatally rather than in fetal life, with exacerbation upon ductus arteriosus closure. Moreover, neonatal embolization itself carries significant risk of iatrogenic cerebral injury, even at the hands of the most experienced practitioners. We have hypothesized that fetal intervention, before acute postnatal cardiovascular and cerebrovascular stress ensues, may decrease mortality and morbidity. Fetuses at great risk of acute decompensation after birth can now be identified with high reliability based on fetal magnetic resonance imaging morphological criteria,2 thereby defining an appropriate cohort for a novel in utero intervention. We present here the first embolized case in a ClinicalTrials.gov-registered study (URL: https://www. clinicaltrials.gov; Unique identifier: NCT04434729), performed with US Food and Drug Administration oversight, applying an institutional review board-approved study protocol3 of ultrasound-guided percutaneous transuterine, transcranial embolization.