285 – Transposition of the great arteries is associated with increased ascending aorta stiffness

Abstract

Transposition of the great arteries (TGA) is the consequences of abnormal aorticopulmonary septation. Animal embryonic data indicate that septation and elastogenesis are related events. It was showed that carotid artery is markedly and constitutionally stiffer in patients with TGA. to assess aortic dimensions and aortic elasticity in patients with TGA using magnetic resonance imaging (MRI). MRI was performed in 29 patients with simple TGA operated by an atrial switch procedure (22 male; mean age 29 ± 4 years) and 29 age and gender-matched healthy subjects. TGA patients showed aortic root dilatation (7.7 ± 2.1 vs 6.2 ± 1.2 cm∑, p = 0, 0018, in systole, and 6.8 ± 2.1 vs 5.0 ± 1.2 cm∑, p = 0.0003, in diastole, at tubular level), reduced aortic root distension (13.5 ± 5.9 vs 24.3 ± 11.7, p<0.0001) and reduced aortic root distensibility (3.5 ± 1.6 vs 5.3 ± 2.4 mmHg −1 .10 −3 , p = 0.0009). Biomechanical properties of the descending aorta and pulse wave velocity were similar in TGA patients and in healthy subjects. Body mass index, systolic blood pressure, diastolic blood pressure and pulse pressure were similar between patients and healthy subjects, and had no influence on ascending aorta stiffness. No significant correlation was found between index of aortic stiffness and right ventricle (RV) function (end-diastolic and end systolic volumes, RVEF, RV mass, presence or absence of myocardial fibrosis). It did not change after indexation to body surface area of RV function values. Aortic stiffness in TGA is markedly increased and localized to the ascending aorta. This property could contribute to the dilatation of the ascending aorta part of the new aorta in arterial switch procedure.