Abstract
The outcomes of patients with hypoplastic left heart syndrome (HLHS) have significantly improved in recent years due to the utilization of the Norwood procedure. Unobstructed outflow through the aortic arch is important for maintaining right ventricular function. Some reports have shown that an aortic arch with a high-degree tapering form leads to increased energy loss; however, the correlation between right ventricular function and the degree of aortic arch tapering remains unknown. This retrospective, single-center analysis aimed to investigate the impact of aortic arch tapering following the Norwood procedure on circulation dynamics and right ventricular function. During the study period, 14 patients who underwent the Norwood procedure for HLHS and enhanced computed tomography before the Glenn procedure were included. The median age of the patients at the time of the Norwood procedure was 30 days (25–269 days), and the median weight was 3.0 kg (2.6–4.4 kg). As an indicator of the degree of tapering of the aortic arch, we used the standard deviation (SD) of the diameters of the ascending aorta, transverse arch, isthmus, and descending aorta (arch SD). There was a significant negative correlation between the cardiac index and arch SD. Furthermore, there was a significant negative correlation between the right ventricular fractional area change and arch SD. In conclusion, an unobstructed and minimally tapered aortic arch is essential for maintaining optimal right ventricular function.