Early surgical intervention for severe aortic stenosis — even without symptoms — proves effective not only in the short term but also over the long term, according to a new study.
Asan Medical Center in Seoul announced Wednesday that a research team led by Professor Kang Duk-hyun of the cardiology department has become the first in the world to demonstrate that asymptomatic severe aortic stenosis patients who undergo surgery have a significantly better chance of surviving beyond 10 years. The findings were published in the New England Journal of Medicine (NEJM), widely regarded as the gold-standard journal for clinical physicians worldwide.
Aortic stenosis is a condition in which the aortic valve — the gateway for blood flowing from the left ventricle to the aorta — becomes calcified due to aging and fails to open properly. While the number of patients is rising along with the aging population, one in three patients has no symptoms, making early detection difficult.
The standard treatment for severe aortic stenosis is aortic valve replacement, in which the damaged valve is replaced with a prosthetic valve such as a mechanical or tissue valve. However, for asymptomatic cases, the optimal timing for surgery has long been debated in the medical community due to the lack of clear guidelines. Because most patients are elderly and face a high risk of complications, a conservative approach — careful monitoring followed by surgery only when symptoms appear — had been the prevailing recommendation.
Professor Kang's team first published findings in NEJM in 2019 showing that early surgery for severe aortic stenosis can significantly reduce cardiovascular mortality even in asymptomatic patients. In the latest study, the team enrolled 145 asymptomatic patients with severe aortic stenosis — defined as a valve opening narrowed to 0.75 square centimeters or less — between July 2010 and April 2015. The patients were divided into an early surgery group of 73 and a conservative treatment group of 72. The early surgery group underwent aortic valve replacement within two months of diagnosis, while the conservative treatment group received surgery only when symptoms developed during the observation period.
Over an average follow-up of 12 years, the rate of operative or cardiovascular death was 24% in the conservative treatment group compared with just 3% in the early surgery group. All-cause mortality was also roughly halved, at 32% in the conservative group versus 15% in the early surgery group. Hospitalization due to heart failure occurred in 19% of the conservative treatment group, while not a single case was recorded in the early surgery group.
The publication marks Professor Kang's third paper in NEJM as a corresponding author since his 2012 study on endocarditis. NEJM is the most authoritative medical journal, with significant influence on treatment guidelines worldwide. Counting all contributions from Asan Medical Center's Heart Institute, this is the institution's tenth NEJM publication — a record for a Korean medical institution.
"In patients with severe aortic stenosis, even during the asymptomatic period, the narrowing of the valve worsens and damages the heart, increasing the risk of sudden death," Professor Kang said. "Even without symptoms, patients diagnosed with severe aortic stenosis on echocardiography should seek early treatment."