Aortic stenosis is the valvular heart disease most frequently requiring surgical treatment in developed countries. In recent years, as the global population has aged, both the incidence and prevalence of this condition have increased substantially. Determining the optimal timing of intervention in a patient with severe aortic stenosis who remains asymptomatic continues to be one of the most debated issues in cardiology practice. For years, clinical practice guidelines have recommended surgery for symptomatic severe aortic stenosis, whereas conservative management has traditionally been favored in patients who have not yet developed symptoms. These guidelines are intended to guide and standardize medical decision-making on the basis of scientific evidence, under the principle of “first, do no harm.” But what happens when new evidence challenges these recommendations? The RECOVERY (Randomized Comparison of Early Surgery versus Conventional Treatment in Very Severe Aortic Stenosis) trial was designed as a randomized clinical study that questioned the traditional strategy of clinical surveillance until symptoms develop. The 4-year follow-up results were published in 2020; long-term outcomes are now available, providing essential information for assessing the effects of early surgery in asymptomatic patients.

RECOVERY was a multicenter, randomized, open-label, parallel-group trial including 145 asymptomatic patients with very severe aortic stenosis, defined as an aortic-valve area ≤0.75 cm² together with a peak aortic jet velocity ≥4.5 m/s or a mean transaortic gradient ≥50 mmHg. Patients were enrolled between July 2010 and April 2015 at several centers in South Korea. Exclusion criteria included age >80 years, exertional dyspnea, syncope or angina, left ventricular ejection fraction <50%, aortic regurgitation, significant mitral-valve disease, or previous cardiac surgery. Patients were assigned in a 1:1 ratio, with randomization stratified according to participating center, to either early surgery (aortic-valve replacement within 2 months after enrollment) or conservative care with echocardiographic follow-up. Patients assigned to conservative care were referred for aortic-valve replacement if symptoms developed, left ventricular ejection fraction fell below 50%, or peak aortic jet velocity increased by more than 0.5 m/s per year. The primary end point was a composite of operative mortality (death during surgery or within 30 days after surgery) or death from cardiovascular causes, with follow-up continuing until at least 10 years after enrollment of the last patient.

With a median follow-up of 12 years in the early-surgery group and 11.2 years in the conservative-care group, the primary end point occurred in 3% of patients assigned to early surgery (2 of 73), compared with 24% of those receiving conservative care (17 of 72). The estimated 10-year cumulative incidence according to Kaplan–Meier analysis was 1% versus 19%, respectively (HR = 0.10; p = .002), corresponding to an NNT of 6 patients to prevent one cardiovascular death within 10 years. The Kaplan–Meier curves showed progressive and sustained separation between the two groups. Death from any cause occurred in 15% versus 32% of patients (10-year cumulative incidence, 11% versus 25%; HR = 0.42), with a number needed to treat of 7.

Regarding secondary end points, no patient in the early-surgery group was hospitalized for heart failure, compared with 19% in the conservative-care group (HR = 0.03). The incidence of thromboembolic events (4% versus 10%) and repeat aortic-valve surgery (4% versus 6%) did not differ significantly between groups. In the conservative-care group, 85% of patients (61 of 72) ultimately underwent aortic-valve replacement during follow-up, either surgical or transcatheter, at a median of 1048 days after randomization, and urgent surgery was required in 19% of those who underwent delayed surgery. Sensitivity analyses, including per-protocol, as-treated, and competing-risk analyses, were consistent with the primary analysis.

On the basis of these findings, the authors conclude that, among asymptomatic patients with very severe aortic stenosis, early surgery is associated with a lower risk of operative mortality or death from cardiovascular causes than conservative care at 10 years of follow-up. These findings reinforce previous evidence from the AVATAR trial, whose extended follow-up also demonstrated a benefit with early surgery.

COMMENTARY:

The study analyzed here represents the extended follow-up, beyond 10 years, of previously published reports. Despite the findings described above, several limitations should be considered. The study population was relatively young and had few comorbidities (mean age 64 years, left ventricular ejection fraction 65%), making it poorly representative of patients with severe aortic stenosis encountered in real-world practice. In addition, competing risk, assessed in terms of noncardiovascular mortality, could reduce the benefit of early intervention in older and more comorbid populations. The definition of very severe aortic stenosis also limits generalizability, since it is uncommon for patients with disease of this severity to remain asymptomatic when assessed in clinical practice. Another limitation is the lack of systematic exercise testing to confirm the absence of symptoms, since clinical assessment depends substantially on patients’ own perception of their functional status. Therefore, the extent to which the enrolled population was truly asymptomatic remains uncertain. Furthermore, part of the long-term follow-up occurred during the COVID-19 pandemic, which may have influenced event detection. Despite the relatively small sample size, the prolonged follow-up distinguishes this trial from other studies that have failed to demonstrate significant differences in mortality.

Finally, these results should not be interpreted as indicating that every patient with severe aortic stenosis should undergo intervention before symptoms develop. Rather, they suggest that there is a subgroup of patients with very severe aortic stenosis and low surgical risk who are unlikely to benefit from waiting until symptoms appear. The challenge lies in identifying these patients at the appropriate time through close surveillance. Achieving this requires interdisciplinary agreement and collaboration so that potentially eligible patients can be discussed at multidisciplinary Heart Team meetings for individualized assessment. It should also be considered that the age of the target population is progressively increasing, meaning that many patients may ultimately benefit from transcatheter aortic-valve replacement. Whether such an intervention provides the same long-term benefits remains to be established.

REFERENCE:

Kang DH, Park SJ, Kim GY, Lee S, Sun BJ, Kim JB, Jung SH, Kim HK, Yun SC, Hong GR, Song JM, Chung CH. Early Surgery or Conservative Care for Asymptomatic Aortic Stenosis at 10 Years. N Engl J Med. 2026 Mar 26;394(12):1167-1174. doi: 10.1056/NEJMoa2511920. PMID: 41880613.