Differences in Severity and Prognosis Between Bicuspid and Tricuspid Severe Aortic Stenosis

Abstract

Background: Bicuspid aortic valve (BAV) often leads to aortic stenosis (AS). However, current severity assessment and treatment strategies do not differentiate between BAV and tricuspid aortic valve (TAV) patients.

Objectives: The purpose of this study was to investigate differences in echocardiographic indices used to evaluate disease severity and to compare long-term outcomes between BAV and TAV.

Methods: We performed a post hoc analysis of 3,815 patients with severe AS enrolled in the CURRENT AS (Contemporary outcomes after sURgery and medical tREatmeNT in patients with severe Aortic Stenosis) registry. Echocardiographic parameters and clinical outcomes were compared between patients with BAV and those with TAV. The primary outcome was all-cause mortality. Sensitivity analyses included propensity-score matching and estimation of HRs for BAV relative to TAV. The median follow-up period was 36.9 months (IQR: 18.2-51.8).

Results: Patients with BAV had higher jet velocity (maximal aortic jet velocity: 4.65 ± 0.87 vs 4.09 ± 0.91 m/s; P < 0.001) and mean pressure gradient (51.6 ± 20.3 vs 39.9 ± 19.3 mm Hg; P < 0.001), with similar aortic valve area (0.70 ± 0.21 vs 0.72 ± 0.18 cm²; P = 0.288) compared to those with TAV. Discordant severity grading was less frequent in BAV than in TAV (34% vs 58%; P < 0.001). Linear regression indicated larger aortic valve area in BAV for equivalent maximal aortic jet velocity and mean pressure gradient values. Five-year all-cause mortality was lower in BAV than in TAV (6.5% vs 45.9%; P < 0.001), with matched-cohort analysis confirming a survival benefit (HR: 0.46; 95% CI: 0.28-0.77; P = 0.003).

Conclusions: Patients with BAV have unique hemodynamic characteristics distinct from TAV. Tailored evaluation criteria for BAV patients may influence both prognosis and treatment strategies.

Keywords: aortic stenosis; aortic valve replacement; bicuspid aortic valve.