Aortic arch reconstruction in patients with hypoplastic left heart syndrome (HLHS) presents a surgical challenge and is associated with a re-intervention rate of 18% (1). Different surgical techniques have been advocated to improve results, but these are dependent on the initial geometry and size of the native aorta and probably also on the flow dynamics. Haller and colleagues sought to investigate the differences in aortic arch growth between patients treated with a Norwood procedure (NP) and patients undergoing an initial palliative procedure with bilateral pulmonary banding and ductal stenting (2). Diameters of the aorta were measured at different times after aortic arch repair and at different locations.