Maladaptive Aortic Properties in Children After Palliation of Hypoplastic Left Heart Syndrome Assessed by Cardiovascular Magnetic Resonance Imaging

Abstract

Background— The status of the reconstructed aorta in hypoplastic left heart syndrome is considered an important determinant of long-term prognosis. Therefore, we assessed the anatomy, elastic properties, and viability of the aorta and right ventricular function in patients with hypoplastic left heart syndrome by cardiovascular magnetic resonance imaging. Methods and Results— Cardiovascular magnetic resonance imaging was performed in 40 patients with hypoplastic left heart syndrome (age, 6.0±2.2 years) and 13 control subjects (age, 6.6±2.2 years). Aortic dimensions and distensibility were calculated at different locations of the aorta using gradient-echo cine imaging at 3.0 T. Additionally, pulse-wave velocity, right ventricular ejection fraction, and aortic late gadolinium enhancement for viability assessment were measured. Compared with control subjects, patients with hypoplastic left heart syndrome had increased axial diameters of the aortic root (36.0±5.5 versus 24.1±2.7 mm/m 2 ; P <0.01), ascending aorta (32.0±5.0 versus 21.3±1.5 mm/m 2 ; P <0.01), and transverse aortic arch (22.7±5.2 versus 18.7±2.5 mm/m 2 ; P <0.01). Wall distensibility was reduced in the ascending aorta (4.1±2.4 versus 13.5±7.2 10 −3 mm Hg −1 ; P <0.01) and transverse aortic arch (5.4±3.6 versus 10.3±3.5 10 −3 mm Hg −1 ; P <0.01). Pulse-wave velocity trended higher in patients ( P =0.06). Reduced distensibility in the ascending aorta correlated with the amount of late gadolinium enhancement in a volume that included the aortic root and the ascending aorta ( r =−0.72, P <0.01), and both parameters correlated with decreased right ventricular ejection fraction. Conclusions— Adverse aortic properties post palliation of hypoplastic left heart syndrome manifest themselves by aortic dilatation, decreased distensibility, and increased volume of nonviable aortic wall tissue. The negative association between aortic late gadolinium enhancement and right ventricular ejection fraction suggests unfavorable aortic-ventricular coupling. The potential impact of these findings on long-term right ventricular function should be evaluated in future studies.