Progressive dilation of the diameter of the aortic root in adults with a bicuspid aortic valve.

Background: To determine the rate of progression of dilation of the aortic root in adults with a bicuspid aortic valve.
Methods: We reviewed retrospectively the transthoracic echocardiograms of 50 adults with a bicuspid aortic valve. Each patient had had at least two examinations made 12 months apart. Measurements were taken at four levels: at the basal attachment of the leaflets of the valve within the left ventricular outflow tract, at the widest point of the sinuses of Valsalva, at the sinutubular junction, and in the ascending aorta 1 cm beyond the sinutubular junction.
Results: Progressive dilation occurred at all levels, ranging from 0.3 mm/yr at the basal attachment within the left ventricular outflow tract to 1.0 mm/yr, 1 cm beyond sinutubular junction. These rates of dilation were greater than the reported rate of 0.8 mm per decade in the normal population. The rate of dilation found in the ascending aorta 1 cm beyond the sinutubular junction was significantly greater than at the other sites (p = 0.005). The 21 patients with baseline measurements greater than 34 mm had a significantly higher rate of progression (p = 0.007). Sex, age, and the degree of valvar obstruction or regurgitation did not significantly influence the rate of progression of dilation.
Conclusion: There is a significantly higher rate of dilation of the aortic root in adults with a bicuspid aortic valve when compared to the normal population. Periodic evaluation of the ascending aorta is essential in these patients, even after replacement of the aortic valve. Other imaging modalities should be considered if the region beyond the sinutubular junction is not well visualized by transthoracic echocardiography.