Our model identified a threshold probability of biventricular circulation above which fetal aortic valvuloplasty provides a 6-year transplant-free survival benefit. The threshold value (26%) is applied to the previously published CART diagram, which identified probabilities of postnatal biventricular circulation based on fetal echocardiographic parameters.16 Green boxes exceed the threshold, i.e., perform FAV; orange is within +/− 10% of the threshold; red boxes fall below the threshold, i.e., No FAV. Adapted with permission from Friedman et al, Improved technical success, postnatal outcome and refined predictors of outcome for fetal aortic valvuloplasty. Ultrasound Obstet Gynecol. 2018;52:212-220.16