Turbulent kinetic energy in the ascending aorta is greater in bicuspid than tricuspid aortic valve stenosis

Background The main determinant of the haemodynamic significance of aortic stenosis (AS) is the irreversible pressure loss that is created by the stenosis. The majority of the pressure loss is caused by conversion/dissipation of turbulent kinetic energy (TKE) to heat. Recent developments in cardiac magnetic resonance 4D flow imaging have allowed the noninvasive assessment of TKE. Bicuspid aortic valve disease is known to be associated with a larger ascending aorta and disordered flow patterns, and we hypothesised that peak TKE would be higher in bicuspid AS than tricuspid AS. Methods 15 patients with bicuspid AS (mean age 63.6 years; mean aortic valve area 1.4cm 2 ; mean dimension of the ascending aorta at the level of the pulmonary artery 3.9cm) and no more than mild other valve disease were compared with 22 patients with tricuspid AS (mean age 72.9 years; mean aortic valve area 1.2cm 2 ; mean dimension of the ascending aorta at the level of the pulmonary artery 3.2cm) and no more than mild other valve disease. All subjects underwent time resolved, three dimensional cine magnetic resonance flow imaging at 3 Tesla, for the assessment of peak TKE. The peak TKE was obtained by integrating the TKE per voxel across the ascending aorta at each time frame of the cardiac cycle. Results