3.2: ascending and Descending Aorta Pulse Wave Velocity and Distensibility in Bicuspid Aortic Valve Patients

Abstract

Purpose

Bicuspid aortic valve (BAV) is a cardiac congenital disease associated with ascending aorta (AAo) dilation. The study of the impact of aortic biomechanics in this population has been limited by technical difficulties. Contrasting results have been reported for distensibility while studies including regional pulse wave velocity (PWV) are still lacking. Using 4D-flow MRI, we assessed AAo and descending aortic (DAo) biomechanical properties and determined their association in BAV aortopathy.

Methods

One-hundred thirty-six BAV patients with no severe valvular disease and 40 healthy volunteers were recruited. The protocol included a 4D-flow acquisition and a set of 2D CINE PC-MRI at 1.5 T. Aortic 3D geometry was reconstructed from 4D-flow-derived angiography and at least 100 analysis planes were identified in the thoracic aorta. Transit time was calculated on the velocity upslope through wavelet analysis[1].CINE PC-MRI were used to compute distensibility. Statistical significance is reported corrected for confounding factors.

Results

Non-dilated BAV and controls have similar AAo and DAo PWV and distensibility. Dilated patients presented lower AAo PWV and higher DAo PWV compared to non-dilated (p < 0.001 and p = 0.017, respectively). Distensibility did not differentiate dilated from non-dilated patients and presented lower association with dilation severity (see Figure).

Conclusions

Confirming for the first time previous findings in abdominal aorta aneurysm and fluid-mechanics theory, AAo PWV is reduced in aneurysmatic BAV patients. BAV aortopathy is related to a stiffer DAo. Regional PWV outperforms distensibility as a marker of local aortic biomechanics. These data exclude congenital aortic wall pathology related to BAV