The Aortic Flow Reversal Ratio: A Quantitative Adjunct to the Bicêtre Score in Vein of Galen Malformation

Background/Objectives: The Bicêtre score for Vein of Galen Aneurysmal Malformation (VGAM) relies on existing end-organ damage. We hypothesized that transthoracic echocardiography (TTE) could quantify significant systemic steal in clinically stable neonates (Bicêtre score ≥ 12). This study evaluates the Aortic Flow Reversal Ratio (AoFRr) as a tool to measure this steal and predict treatment outcomes. Methods: In a single-center retrospective study of patients with VGAM, the AoFRr (the ratio of the diastolic reversal velocity time integral to the systolic forward volume time integral) was calculated via TTE in the abdominal aorta at the level of the diaphragm before and after endovascular embolization. Over the study period, the cohort underwent a total of 30 endovascular interventions and 49 TTEs. Pre-intervention AoFRr was correlated with the Bicêtre score, and post-intervention changes were analyzed for association with the need for subsequent embolizations. Results: In a cohort of 12 patients with a median Bicêtre score of 18, 83.3% had pre-intervention aortic diastolic flow reversal. The median pre-intervention AoFRr was 0.81, indicating substantial systemic steal despite clinical stability. A post-intervention AoFRr reduction of ≥85% was significantly associated with a lower likelihood of requiring re-intervention (p = 0.0253). Conclusions: The AoFRr quantifies substantial hemodynamic steal in VGAM patients who appear clinically stable by the Bicêtre score. Its reduction following embolization predicts a more favorable clinical course. The AoFRr is a valuable, non-invasive adjunct for risk stratification and may help optimize the timing of endovascular intervention.