NATURAL HISTORY AND CLINICAL BURDEN OF MODERATE AORTIC STENOSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract Objectives The aim of this study was to assess the natural history and clinical burden of moderate aortic stenosis and to investigate the interaction of left ventricular ejection fraction and of age with prognosis. Background The mortality risk of patients with moderate aortic stenosis is not well known but recent studies suggested that it might negatively affect prognosis. Methods A systematic research was conducted on PubMed. The inclusion criteria were: 1) inclusion of patients with moderate aortic stenosis; 2) report of the survival at 1-year follow-up (minimum). Incidence ratios related to all-cause mortality in patients and controls of each study were estimated and then pooled using a fixed effects model. Meta-regression analysis was performed to assess the impact of left ventricular ejection fraction and age on the prognosis of patients with moderate aortic stenosis. Results Fifteen studies and 11,596 patients with moderate aortic stenosis were included. All-cause mortality was significantly higher among patients with moderate aortic stenosis than among controls: 10.7% (95% CI: 0.1010-0.1136) vs 4.5% (95% CI: 0.0438-0.0454) at 1-year, 17.7% (95% CI: 0.1692-0.1854) vs 7.6% (95% CI: 0.0754-0.0775) at 2-year, 23.0% (95% CI: 0.2204-0.2387) vs 9.9% (95% CI: 0.0973-0.0997) at 3-year, 27.9% (95% CI: 0.2685-0.2899) vs 11.9% (95% CI: 0.1177-0.1203) at 4-year, and 32.4% (95% CI: 0.3125-0.3360) vs 14.2% (95% CI: 0.1402-0.1430) at 5-year follow-up. Left ventricular ejection fraction did not significantly impact on the prognosis of patients with moderate aortic stenosis (estimate = -0.0020; 95% CI: -0.0078-0.0038; p = 0.4584), unlike of age (estimate = 0.0067; 95% CI: 0.0007-0.0127; p = 0.0323). Conclusions Moderate aortic stenosis is not a benign disease. Further studies are necessary to confirm the prognostic impact of this valvulopathy and the possible benefit of the aortic valve replacement. All-cause mortality of patients (red) vs controls (black) at 1-, 2-, 3-, 4- and 5-year follow-up.