Bicuspid aortic valve (BAV) is associated with high incidence of ascending aortic aneurysm. In BAV sporadic form, changes in outflow's hemodynamic secondary to the valvular morphotype are said to play a prominent role in the aortic dilatation. We aimed at comparing the different ascending aorta segment diameters according to the morphotype and the function of the BAV.

We evaluated 174 patients with sporadic BAV by transthoracic echocardiography. The valvular function was defined as either Aortic Insufficiency (AI) if Grade≥2 and aortic Stenosis (AS) if mean gradient>20mmHg. Aortic diameters were measured at the Valsalva sinus, tubular ascending aorta and at the aortic arch. Kruskal-Wallis, Mann–Whitney and Spearman tests were used for comparisons.

Among the non-operated patients, Sievers’ morphotype was type 1LR for 63%, type 1NR for 18%, and other types counted for 19%. The Valsalva sinus diameter did not differ according to the Sievers’ type (P=0.78). The type 1LR type compared to the type1NR appeared to have a wider tubular aorta, but not significantly (42.3±8.5 vs. 36.4±7.3mm; P=0.06). Aortic valve function was distributed as follows: AI: 39%, AS: 20%, Both: 9%, Normal: 32%. Comparison of the different valve dysfunctions revealed a difference at the Valsalva (P<10–4) and the tubular aorta (P=0.001) but not at the aortic arch level (P=0.62). AI was highly associated with an increase of the aortic diameters of any segment, excepting for the arch. In addition, aortic diameters increased with age in case of AI (Valsalva: r=0.28; P=0.02; Tubular aorta: r=0.27; P=0.02) and not in case of AS (r=–0.06; P=0.73 and r=–0.03; P=0.84).

Our results showed the tremendous role of AI in the aortic dilation of all segments except the arch. However no influence of BAV morphotype was noticed on aortic diameters. Our results give rise to the relatively limited influence of the valvular morphology in the development of aortic dilation.