Aortic Valve Replacement vs Conservative Treatment in Asymptomatic Severe Aortic Stenosis: Long-Term Follow-Up of the AVATAR

The AVATAR Trial addressed the question of when and how to treat asymptomatic patients with severe aortic stenosis (AS) and normal left ventricular (LV) systolic function. In the current report, the authors present the extended follow-up. The AVATAR trial randomly assigned patients with severe, asymptomatic AS (negative exercise stress testing in all patients) and LV ejection fraction greater than 50 percent to undergo either early surgical aortic valve replacement (SAVR) or conservative treatment with a watchful waiting strategy. The primary endpoint was a composite outcome of all-cause death, acute myocardial infarction, stroke, or unplanned hospitalization for heart failure (HF). A total of 157 low-risk patients were randomly assigned to either the early SAVR group (n=78) or the conservative treatment group (n=79). In an intention-to-treat analysis, after a median follow-up of 63 months, the primary composite endpoint outcome event occurred in 18 out of 78 patients (23.1 percent) in the early SAVR group and 37 out of 79 patients (46.8 percent) in the conservative treatment group (hazard ratio (HR) early SAVR versus conservative treatment 0.42; 95 percent confidence interval (CI) 0.24–0.73, p=0.002). The Kaplan-Meier estimates for individual endpoints of all-cause death and HF hospitalization were significantly lower in the early SAVR group compared to the conservative group (HR 0.44; 95 percent CI 0.23–0.85, p=0.012 for all-cause death, and HR 0.21; 95 percent CI 0.06–0.73, p=0.007 for HF hospitalizations). The authors conclude that after an extended follow-up, asymptomatic patients with severe AS and normal LV ejection demonstrate better clinical outcomes with early SAVR than patients treated with conservative treatment and watchful waiting.