MRI evaluation of biophysical proprieties of ascending aorta in bicuspid aortic valve

Introduction: abnormal biophysical proprieties of ascending aorta in bicuspid aortic valve (BAV) have already been demonstrated also by magnetic resonance (MRI). However MRI findings show large variations between different series. Aim: to detect aortic wall biophysical properties in young subjects with BAV, by new MRI indexes referred as Relative Velocities of Maximal Systolic Distension (RVSD) and Relative Velocities of Maximal Diastolic Recoil (RVDR). Methods: we enrolled 23 consecutive young subjects with BAV, without significant aortic valve dysfunction, aged from 9 to 21 years old (mean 17?5 y.o.), and ten healthy volunteers age and sex matched as control group. All the subjects underwent MRI exam comprehensive of phase-velocity-mapping acquisition in order to assess aortic flow and cross sectional area (CSA) excursion with high temporal resolution (approximately 10-3sec), at several aortic level Systemic pressure was non-invasively measured at each acquisition. CSA, systemic vascular resistance (SVR), aortic wall distensibility and flow wave velocity propagation (FVP) have been evaluated at each location as previously described. The variation in percentile of maximal CSA was measured by the difference CSA between each cardiac phase and the preceding (percentile of maximal area/10-3 sec).RVSD was defined as the highest ascending aorta CSA systolic augmentation in percentile and RVDR as the highest diastolic reduction CSA in percentile. Results: the ascending aortic CSA was significantly larger in BAV compared to control (796?312vs. 514?146 mm2 p=0.01) with a significantly lower distensibility (5.3?2.8 vs. 8.3?3.8 103 mmHg-1 p=0.01). FVP resulted significantly higher in BAV than in control (1.8?0.75 vs. 1.26?0.4 mm/msec. p< 0.05). RVSD was significantly lower than in control (4.2?1.12 vs. 8.9?2%tile of maximal area/10-3 sec p<0.0001, as well as RVDR (-4.39?1.3 vs. -8 ?3 %tile of maximal area/10-3 sec p