The Relationship Between Aortic Arch Form and Right Ventricular Function After the Norwood Procedure

Background: The outcomes for infants with hypoplastic left heart syndrome (HLHS) have improved in recent years, partly due to advances in the Norwood procedure. An unobstructed aortic arch is important for maintaining right ventricular function. Previous studies have suggested that a highly tapered aortic arch may increase energy loss; however, the relationship between aortic arch geometry and right ventricular function remains unclear. Methods: This study was a retrospective single-center analysis. Results: During the study period, a total of 14 patients with HLHS who underwent the Norwood procedure and had contrast-enhanced computed tomography prior to the Glenn procedure were included. The median age at the Norwood procedure was 30 days (25-269), and the median weight was 3.0 kg (2.6-4.4). As an indicator of aortic arch tapering, we used the standard deviation of diameters measured at the ascending aorta, transverse arch, aortic isthmus, and descending aorta (Arch SD). There was a significant negative correlation between Arch SD and cardiac index. A significant negative correlation was also observed between Arch SD and right ventricular fractional area change. Conclusions: A more uniform and less tapered aortic arch geometry was associated with higher right ventricular function and cardiac index following the Norwood procedure for HLHS.