0502: Aortic root dilatation and stiffness assessed by magnetic resonance imaging in adults with repaired tetralogy of Fallot

Abstract

We aimed to assess dimensions and biomechanics of the thoracic aorta in patients with surgically repaired tetralogy of Fallot (TOF), using Cardiac Magnetic Resonance (CMR). Aortic root dilatation frequently occurs in TOF and can lead to aortic regurgitation (AR), aortic aneurysms and its complications. Histological studies in TOF have shown abnormalities of the aortic media that can predis-pose to aortic root dilatation. 50 patients (aged 29±12 years) with repaired TOF and 50 control healthy subjects (aged 29±11 years) matched for age and sex underwent CMR imaging, with standard cine and velocity sequences. The aortic root dimensions were assessed at end-diastole at the following levels: aortic annulus, sinus of Valsalva, sinotubular junction (STJ), ascending and descending aorta. Aortic elasticity was evaluated by aortic distensibility and pulse wave velocity (PWV). CMR included conventional left ventricle (LV) and right ventricle (RV) systolic function and volume study, AR fraction measure. Diameters of the aorta indexed to the body surface area were significantly increased in TOF compared to controls at level of sinus of Valsalva (22.6±3.8 vs 17.0±2.0mm/m 2 ; p<0.001), STJ (18.2±4.1 vs13.3±1.7mm/m 2 ; p<0.001) and ascending aorta (20.0±4.3 vs 14.3±2.0mm/m 2 ; p<0.001). In contrast, the diameter at annulus and descending aorta was no significantly different. Ascending aorta has a reduced distensibility in patients compared to controls (3.4±2.2 vs 6.6±2.4x10 –3 mmHg –1 ; p<0.001) and PWV in the aortic arch is significantly increased (8.1±6.6 vs 4.3±1.3 m/s; p<0.001). Unlike controls, PWV and aortic velocity were not correlated with age in TOF. AR occurs more often in patients with TOF than in controls. Aortic dilatation and stiffness were not related to age at surgical repair. Both LV and RV systolic functions were moderately impaired in patients with TOF. Aortic root dilatation is associated with increase in aortic stiffness. These parameters can be easily measured by CMR.