The following is a summary of “Patterns of Aortic Dilation in Tetralogy of Fallot: An Analysis of 100 Fetal Echocardiograms Compared With Matched Controls,” published in the November 2023 issue of Cardiology by Dasgupta et al.

In tetralogy of Fallot (TOF), aortic dilation is a common yet poorly understood occurrence, with uncertain risks of progression and dissection. The dilation mechanism is usually attributed to increased fetal blood flow, but there’s speculation about unequal truncus arteriosus septation leading to a larger aorta and relatively hypoplastic pulmonary artery (PA). To explore this, researchers examined the aorta-to-PA ratio and sums of great artery dimensions in TOF versus matched controls across gestation. Their retrospective single-center study (2014–2020) included 100 TOF fetal echocardiograms (36% with TOF-PA), displaying a median gestational age of 31 weeks and maternal age of 34 years. Comparisons between sums of artery dimensions showed no disparities between TOF with pulmonary stenosis and controls. However, these sums were significantly lower in TOF with pulmonary atresia than in controls (P < 0.01). Interestingly, the aorta to PA ratio remained stable throughout gestation, implying proportional growth (Pearson’s r = 0.08 [95% CI, -0.12 to 0.27], -0.06 [95% CI, -0.25 to 0.14]).

The study suggests that while fetal TOF exhibits a notably larger aorta, its growth pattern remains consistent across gestation, resembling controls. Notably, TOF with pulmonary atresia shows distinct characteristics, indicating a separate profile from TOF with pulmonary stenosis, marked by smaller artery dimension sums. These findings prompt further investigations into the developmental mechanisms underlying aortic dilation in TOF, hinting at intrinsic developmental contributions to this phenomenon.

Source: ahajournals.org/doi/10.1161/JAHA.123.030083