Epicardial adipose tissue predicts adverse outcomes in asymptomatic aortic stenosis

Abstract Background Epicardial adipose tissue (EAT) represents a metabolically active visceral fat depot within the pericardium, associated with cardiovascular risk factors, but little is known about its role in patients with aortic stenosis (AS). Purpose This study sought to investigate the association of EAT volume with disease severity, disease progression, and outcome of asymptomatic patients with AS. Methods In a post-hoc analysis of 124 patients with asymptomatic mild to severe AS participating in the prospective SALTIRE2 trial, baseline EAT volume was quantified on computed tomography angiography (CTA) using fully automated deep learning-enabled software (Figure 1A & 1B). AS disease severity was calculated at baseline and 1-year. The primary endpoint was defined as all-cause mortality during follow-up. Results Median EAT volume was 100 [74-139]mL, and was higher in men compared to women (109 [78-148]mL vs 79 [62-106]mL; p=0.004). There was a significant correlation between EAT volume and baseline troponin level (r=0.23, p=0.009), left ventricular (LV) mass (r=0.46, p<0.001), and LV ejection fraction (LVEF, r=-0.28, p=0.002). EAT volume did not correlate with AS severity as assessed by echocardiography (aortic valve peak velocity (Vmax): r=0.02, p=0.83) or CT calcium score (r=0.04, p=0.66). Equally, no correlation was observed between baseline EAT volume and subsequent disease progression (1-year change in Vmax: r=0.02, p=0.86). During the median follow-up of 48 [26-73] months, a total of 23 (18%) patients reached the primary endpoint. Both EAT volume (hazard ratio (HR) 1.57, 95% confidence interval (CI) 1.05-2.35; p=0.029) and troponin level (HR 1.43, 95%CI 1.13-1.82; p=0.003) were significant predictors of all-cause mortality in multivariable cox regression. Patients with EAT volume >90mL had worse survival compared to patients with EAT volume ≤90mL (p = 0.026, Figure 1C). Conclusions In a prospective trial of patients with asymptomatic AS, EAT volume showed marked prognostic importance and predicted all-cause mortality during follow-up. Higher EAT volume was associated with increased troponin value, increased LV mass, and reduced LVEF, and could therefore be a marker of impaired myocardial health, but further studies are warranted to elucidate the exact underlying mechanisms.