Bicuspid aortic valve morphology and its association with aortic diameter: an echocardiographic study

Bicuspid aortic valve (BAV) is strongly associated with aortopathy. Previous studies have suggested that various types of bicuspid aortic valve morphology may differently affect the aortic dilatation.

To evaluate the impact of BAV cusp fusion morphology (type I - right-left coronary cusp fusion; type II - right-noncoronary cusp fusion) on the diameters of the aorta.

BAV morphology was evaluated retrospectively in a group of 67 consecutive patients with BAV. The control group comprised 1000 randomly selected patients with normal tricuspid aortic valve. Aortic dimensions and other echocardiographic parameters were obtained from the echocardiography database of our department. The diameters of aorta in both BAV sub-types were evaluated at the level of: annulus, the sinus of Valsalva, the sinotubular junction, and the ascending aorta and at the level of the ascending aorta in the control group.

Patients with BAV were mainly male (78%), with a mean age of 55.3 ± 16.7 years. The dominant morphology of BAV in the study group was type I (n = 46; 69%). It was associated with increased aortic dimension in comparison to type II BAVs at the level of the sinuses of Valsalva (38.4 ± 5.2 vs. 34.0 ± 4.6 mm, p = 0.002), the sinotubular junction (33.1 ± 5.8 vs. 29.6 ± 5.0 mm, p = 0.035), and the ascending aorta (41.6 ± 7.1 vs. 36.6 ± 6.1 mm, p = 0.006). Indexed aortic diameter was also increased in type I BAV at the level of sinuses of Valsalva (19.6 ± 2.7 vs. 18.1 ± 1.6 mm/m2, p = 0.008) and the ascending aorta (21.3 ± 3.4 vs. 19.3 ± 3.4 mm/m2, p = 0.048). The dimensions of the ascending aorta exceeding the upper normal range limit based on control-group measurements (44.3 mm) were observed more frequently in type I than in type II (33% vs. 10%, p = 0.044). Aortic regurgitation (moderate or severe) occurred in similar percentages of both BAV subtypes (type I: 37% vs. type II: 33%, p = 0.774). There were also no significant differences in aortic valve area (2.2 ± 1.1 vs. 2.0 ± 1.4 cm2, p = 0.163), indexed aortic valve area (1.1 ± 0.6 vs. 1.0 ± 0.6, p = 0.337), peak transvalvular gradient (35.3 ± 20.5 vs. 39.1 ± 28.9 mm Hg, p = 0.862), and mean gradient (18.6 ± 12.3 vs. 22.7 ± 18.2 mm Hg, p = 0.571) and left ventricular ejection fraction (51.8 ± 11.6 vs. 51.8 ± 12.2%, p = 0.978) between type I and type II BAV groups.

Type I BAV cusp fusion morphology is more commonly associated with dilatation of the aorta than type II, especially at the level of the sinus of Valsalva and the ascending aorta.