Objectives The timing of aortic valve replacement (AVR) remains controversial in symptomatic patients with normal flow, low-gradient severe aortic stenosis (AS) and preserved LVEF. We sought to compare long-term mortality of early AVR versus a watchful observation strategy.

Methods From 2000 to 2011, we prospectively evaluated 284 consecutive symptomatic patients (136 men, age 68±10 years) with normal flow, low-gradient severe AS and preserved LVEF who were potential candidates for early AVR. Normal flow, low-gradient severe AS was defined as indexed aortic valve area <0.6 cm²/m² with mean gradient <40 mm Hg and stroke volume index ≥35 mL/m². Early AVR was performed on 98 patients (early AVR group), while the watchful observation strategy was selected for 186 patients (watchful observation group). Patients in the watchful observation group were referred for AVR if mean gradient was ≥40 mm Hg during follow-up.

Results There were no significant differences between the early AVR and the watchful observation groups for the risk of overall mortality (HR 0.94 for the early AVR; 95% CI 0.51 to 1.73) or for the estimated actuarial 8-year mortality rates (17±5% vs 27±5%, p=0.84) in the overall cohort. Society of Thoracic Surgeons score, comorbidity index, age, coronary artery disease, aetiology of AS and performance of AVR were associated with overall survival. For 83 propensity-score-matched pairs, the risk of overall death was not significantly different between the two groups (HR 1.13 for the early AVR, 95% CI 0.55 to 2.35, p=0.74).

Conclusions Early AVR and watchful observation strategy show similar survival in symptomatic patients with normal flow, low-gradient severe AS and preserved LVEF. Watchful observation with timely performance of AVR should be considered a therapeutic option.