Aortic stenosis progression among patients with bicuspid aortic valve

Abstract

Abstract Background Bicuspid aortic valve (BAV) is associated with an increased risk of aortic stenosis (AS). The role of AS progression rate, its determinants, and prognostic implications need to be better understood in patients with BAV-AS. Aim This study aims to compare AS progression rate between patients with BAV and tricuspid aortic valve (TAV), its determinants, and its impact on clinical outcomes. Methods We retrospectively included patients who had undergone > 1 transthoracic echocardiogram (TTE) documenting AS and preserved left ventricular ejection fraction (LVEF). Moderate to severe aortic valve regurgitation and aortic prosthetic valves were excluded. Patients with suspected BAV in TTE and a confirmatory CT scan were identified. A greedy matching was used to match patients with BAV and patients with TAV on age and sex in a ratio 1:1. Aortic peak velocity (APV) was modeled as a function of time using a mixed-effects nonlinear model to capture possible biphasic progression. A core model parameter reflecting AS rate of progression was calculated and compared between patients with BAV-AS and TAV-AS. Multivariate linear regression was used to explore possible predictors of AS progression. All-cause death was compared between patients with BAV and TAV. Results We matched 80 patient-pairs from within our study cohort by age and sex (age 54 ± 11 years, 40 % female). Follow-up time was higher for patients with tricuspid aortic valves (TAV) (5.9±2.6 years vs. 4.6±2.8 years, p<0.01). Patients with TAV-AS had a higher prevalence of cardiovascular risk factors (arterial hypertension [81 % vs. 41 %, p<0.001], diabetes mellitus [39% vs. 8%, p<0.001], and dyslipidemia [71 % vs. 26 %, p<0.001]). Baseline APV was similar between patients with TAV-AS and BAV-AS (2.9±0.9 m/s vs. 2.7±1.0 m/s, p=0.05), but AS progression rate was higher among patients with TAV-AS (logistic growth rate: 0.11±0.04/year vs. 0.02±0.04/year, p<0.001). No interaction was seen between aortic valve morphology and comorbidities with respect to AS progression rate. TAV-AS was associated with increased rate of all-cause death (p=0.02) but failed to remain a significant predictor of mortality after multivariate adjustment for baseline comorbidities and AS rate of progression. Conclusion In our matched cohort, the BAV-AS progression rate was lower than TAV-AS. BAV-AS was associated with lower mortality despite similar baseline AS severity, possibly reflecting a slower AS progression and a decreased burden of cardiovascular risk factors in this population.