Morphology of the native ascending aorta after the Norwood procedure for aortic atresia: impact on survival and right ventricular dysfunction.

OBJECTIVES To evaluate the impact of variable morphology of the native ascending aorta after the Norwood I procedure in patients with hypoplastic left heart syndrome/aortic atresia on long-term survival and systemic right ventricular dysfunction. METHODS Of 151 survivors of the Norwood procedure for hypoplastic left heart syndrome/aortic atresia at our institution between January 2001 and December 2020, we included patients with available and measurable aortography prior to stage II palliation. Diameter of the native ascending aorta, length of the native ascending aorta, and the angle between the the native ascending aorta and the proximal pulmonary artery were measured. We investigated the impact of these morphologic parameters on the mortality and the right ventricular dysfunction (defined as at least moderate). RESULTS Angiography was available in 78 patients. Median diameter of native ascending aorta was 3.2 mm (2.6-3.7), median length of native ascending aorta was 15.4 mm (13.3-17.9), and median angle between the native ascending aorta and the proximal pulmonary artery was 44° (35° - 51°). During median follow-up of 6.5 years, eight (10%) patients died and systemic right ventricular dysfunction occurred in 19 patients (24%). No significant association between the aortic morphology and mortality could be detected. Right ventricular function was negatively affected by a larger angle between the native ascending aorta and the proximal pulmonary artery and (odds ratio 1.07 [1.01-1.14], P= 0.02). CONCLUSIONS In survivors of the Norwood procedure for hypoplastic left heart syndrome/aortic atresia with available angiography, no significant association between the native aortic morphology and mortality could be demonstrated after stage II palliation, within the scope of this limited study. A larger anastomosis angle between the native ascending aorta and the proximal pulmonary artery emerged as a risk factor for right ventricular dysfunction.