1045 MRI evaluation of biophysical proprieties of ascending aorta in bicuspid aortic valve
© Aquaro et al; licensee BioMed Central Ltd. 2008
Published: 22 October 2008
Bicuspid aortic valve (BAV) is the more frequent congenital cardiac malformation affecting 1 to 2% of the population and may be complicated by valvular dysfunction and infective endocarditis. In addition BAV is associated with aortic wall abnormalities leading to enlargement of the ascending aorta and risk of aneurysm formation and dissection independently of the valvular function.
To detect aortic wall biophysical properties differences between young patients with BAV matched with control subjects by means magnetic resonance flow mapping evaluation.
We enrolled twenty-five consecutive patients with BAV, without significant aortic valve disease, aged from 9 to 21 years old (mean age 15 ± 5 y.o.), and ten healthy volunteers age and sex matched as control group. All the subjects underwent a cardiac MRI study comprehensive of phase velocity mapping acquisition at several aortic level (proximal ascending aorta, distal ascending aorta, thoracic aorta, and at diaphragmatic level). In order to obtain a high temporal resolution of aortic wall excursion, approximately 10-3 sec, we set the number of cardiac phases according to the heart rate. The systemic pressure (P) was non-invasively measured at each acquisition. Cross-sectional area (A) and aortic wall distensibility (measured as follow: D = (Amax-Amin)/[Amin × (Pmax - Pmin)]) have been evaluated at each location. The relative velocities of maximal systolic distension and diastolic recoil (RVSD and RVDR respectively) were measured in ascending aorta, expressed as the relative change of cross-sectional area in each cardiac phase (percentile of maximal area/10-3 sec). Flow wave velocity propagation (FVP) was measured as the distance between ascending and descending aorta divided by the flow velocity peak delay.
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