Novel Fetal Embolization Technique via Transcardiac Transarterial Ultrasound- and Fluoroscopy-Guided Endovascular Surgery for Vein of Galen Malformation: Preclinical Study in the Fetal Lamb

Objective: Vein of Galen malformation is associated with significant perinatal morbidity and mortality. Postnatal management typically relies on transarterial embolization of the feeding arteries. To date, fetal therapeutic efforts focused on the transvenous approach. This study aimed to preclinically evaluate the feasibility and safety of a prenatal transarterial approach: Fetal Embolization via Transcardiac Transarterial Ultrasound- and fluoroscopy-guided Surgery (FETTUS). Method: MR-angiography was initially performed in neonatal lambs to identify a target artery for embolization. FETTUS was then standardized in fetal lambs at varying gestational ages. Under maternal–fetal anesthesia, laparotomy-assisted fetal left ventricular access was obtained under ultrasound guidance, a microcatheter was advanced to the target artery under fluoroscopy, and embolization was performed with N-butyl cyanoacrylate. The primary outcome was fetal survival ≥ 30 minutes after confirmed embolization. Results: The internal maxillary artery was chosen as the target artery for embolization. Three fetal lambs underwent successful embolization (100%) at 130 days of gestation (term = 145 days; 2.8 ± 0.6 kg), two out of six (33%) at 100 days of gestation (0.9 ± 0.3 kg) and finally 6 out of 7 (86%) at 120 days of gestation (2.3 ± 0.4 kg). No non-target embolization, ischemia, or hemorrhage was observed on postmortem examination within the limitations of the observations obtained at 30 minutes after the procedure. Conclusions: FETTUS is feasible and safe in fetal lambs at a gestational age equivalent to 30 weeks in humans.