Timing of Surgery in Patients With Asymptomatic Severe Aortic Stenosis
Kang D, Park S, Lee S, et al. Early surgery or conservative care for asymptomatic aortic stenosis. N Engl J Med. 2020;382:111-119.
Commentary
Aortic stenosis is a progressive disease that can lead to angina, heart failure, and death.1A higher mortality rate is reported in patients with symptomatic aortic stenosis, as compared to patients with asymptomatic disease, and current guidelines require symptoms to be present in order to proceed with aortic valve replacement.2 Management of asymptomatic patients is often determined by the treating physician, with treatment decisions based on multiple factors, such as left ventricular function, stress test results, and the local level of expertise for surgery.2
In this context, the RECOVERY investigators report the findings of their well-designed randomized controlled study assessing patients with asymptomatic severe aortic stenosis, which was defined as aortic valve area ≤ 0.75 cm2 and either transvalvular velocity > 4.5 m/s or a mean gradient ≥ 50 mm Hg. Compared to patients who received conservative care, patients who underwent early valve surgery had a significantly lower rate of a composite of operative mortality or death from any cardiovascular causes during follow-up. Notably, the number needed to treat to prevent 1 death from cardiovascular causes within 4 years was 20.
The strengths of this trial include complete long-term follow-up (> 4 years) and low cross-over rates. Furthermore, as the study targeted a previously understudied population, there were a number of interesting observations, in addition to the primary endpoint. First, the risk of sudden death was high in patients who received conservative care, 4% at 4 years and 14% at 8 years, a finding contrary to the common belief that asymptomatic patients are at lower risk of sudden cardiac death. Second, 74% of patients assigned to initial conservative care required aortic valve replacement during the follow-up period. Furthermore, when the patients assigned to conservative care required surgery, it was often performed emergently (17%), which could have contributed to the higher mortality in this group of patients. Finally, hospitalization for heart failure was more common in patients randomized to conservative care compared to patients with early surgery. These findings will help physicians conduct detailed, informed discussions with their patients regarding the risks/benefits of early surgery versus conservative management.
There are a few limitations of the RECOVERY trial to consider. First, this study investigated the effect of surgical aortic valve replacement; whether its findings can be extended to transcatheter aortic valve replacement (TAVR) requires further investigation. Patients who were enrolled in this study were younger and had fewer comorbidities than typical patients referred for TAVR. Second, all patients included in this study had the most severe form of aortic stenosis (valve area ≤ 0.75 cm2 with either a peak velocity of ≥ 4.5 m/s or mean gradient ≥ 50 mm Hg). Finally, the study was performed in highly experienced centers, as evidenced by a very low (0%) mortality rate after aortic valve replacement. Therefore, the finding may not be applicable to centers that have less experience with aortic valve replacement surgery.
Applications for Clinical Practice
The findings of the RECOVERY trial strongly suggest a mortality benefit of early surgery compared to conservative management in patients with asymptomatic severe aortic stenosis.
–Taishi Hirai, MD
