Prognostic Implications of Bicuspid and Tricuspid Aortic Valve Phenotype on Progression of Moderate Aortic Stenosis and Ascending Aorta Dilatation

Abstract

Studies on the impact of aortic valve anatomy (bicuspid aortic valve [BAV] or tricuspid aortic valve [TAV]) on the progression of moderate aortic stenosis (AS) and ascending aorta (AA) dilatation and its prognostic implications are limited. From 1991 to 2016, 288 asymptomatic patients with moderate AS detected during index echocardiography with at least 1 year of echocardiographic follow-up were retrospectively studied. Baseline clinical and echocardiographic characteristics were compared between patients with BAV (n=80) and patients with TAV (n=208). Co-primary outcomes were 1-year hemodynamic and anatomic progression of AS and AA dilatation. Secondary end points were the incidence of AA rapid progressors, all-cause mortality, aortic valve replacement, and congestive heart failure. Determinants of AS progression, AA diameters, AA dilatation, and prognostic outcomes were evaluated. Similar 1-year progression of the aortic valve peak velocity, Vmax (9 ± 18 vs 9 ± 23 cm/s), mean gradient (1.5 ± 2.3 vs 1.3 ± 3.2 mm Hg), and aortic valve area (AVA) (-0.04 ± 0.09 vs -0.05 ± 0.10 cm2) were noted for BAV and TAV groups, respectively. One-year progressions of AA were similar at Valsalva (0.11 ± 0.88 vs 0.14 ± 1.10 mm) and tubular levels (0.12 ± 0.68 vs 0.30 ± 1.51 mm) in BAV and TAV groups, respectively. A trend toward increased rapid AA progression in patients with BAV (31.3%) was observed compared with patients with TAV (14.8%, p=0.099). BAV was associated with progression of Vmax (β=0.17, p=0.036), the dimensionless index (β=-0.17, p=0.008), and AVA (β=-0.14, p=0.048), but not mean gradient after adjusting for age, baseline severity indexes, gender, hypertension, diabetes, and body surface area. Although BAV was a determinant of larger baseline AA diameter, there was no significant association between BAV and AA rapid progressors. Adjusted Kaplan-Meier curves demonstrated no differences in congestive heart failure, aortic valve replacement, or mortality between valve morphology. In conclusion, there was a similar 1-year disease progression in terms of AVA, Vmax, mean gradient, and AA diameters between patients with BAV and patients with TAV. BAV was associated with a significant increase in Vmax, dimensionless index, and AVA after adjusting for important confounders. Close and prolonged follow-up is warranted in both groups of patients.