Unicuspid aortic valve disease: a magnetic resonance imaging study

Congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI).

MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 +/- 4.7 cm (2) vs. 8.7 +/- 2.3 cm (2), p < 0.01 and 4.6 +/- 0.7 cm vs. 3.6 +/- 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 +/- 0.6 cm vs. 2.3 +/- 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 +/- 0.5 cm vs. 2.6 +/- 0.3 cm, p < 0.05).

In UAV, visualization of valve morphology by MRI is possible with good image quality. Valve morphology was classified as unicuspid unicommissural in all UAV patients. Dilatation of the proximal aorta > 4.5 cm is a frequent finding in UAV. Additional assessment of aortic dimensions is therefore recommended in patients with UAV.