Dilatation of the ascending aorta in bicuspid aortic valve disease: a magnetic resonance imaging study

Bicuspid aortic valve disease (BAV) is increasingly recognized as a disease of the entire proximal aorta including both valvular and vascular complications. The aim of our study was to assess the dimensions of the thoracic aorta using MRI in a broad spectrum of BAV and tricuspid aortic valve disease (TAV) and to define the prevalence of the dilatation of the ascending aorta (AA) >or= 4.5 cm in severe BAV disease.

MRI studies were performed on a 1.5 T scanner in a total of 195 consecutive patients with aortic valve disease. Eighty-four aortic valves were classified as BAV and 103 as TAV. In 8 patients, classification of the aortic valve was not possible due to poor image quality. Mean diameters of the AA were significantly greater in BAV compared to TAV (4.39+/-0.85 Vs. 3.55+/-0.47 cm, P<0.0001), whereas no differences were observed in the mean diameters of the aortic arch. Diameters of the descending aorta were slightly smaller in BAV compared to TAV (2.45+/-0.43 Vs. 2.58+/-0.31 cm, P<0.05). In BAV, AA dilatation was independent of the severity of valve dysfunction. In TAV, aortic regurgitation but not stenosis correlated weakly with AA dilatation. Prevalence of AA dilatation >or= 4.5 cm in BAV with severe aortic stenosis and regurgitation was 38% and 41%, respectively.

Dilatation of the proximal aorta is a frequent finding in BAV and independent of the severity of valve dysfunction. With respect to the high prevalence of AA dilatation >or= 4.5 cm in BAV with severe valve dysfunction, careful assessment of the dimensions of the AA is crucial to identify patients in whom concomitant AA replacement is indicated according to current guidelines.