Kang Duk-hyun, a professor of the Department of Cardiology at Asan Medical Center, has recently published a research paper in the New England Journal of Medicine (NEJM), as the lead researcher and corresponding author.
|Professor Kang Duk-hyun|
The study, titled "Early surgery versus conservative care for asymptomatic aortic stenosis," presents a treatment method for severe asymptomatic aortic stenosis, which is one of the most common diseases of old age. It is the second study Kang published in the NEJM.
The journal stressed that hospitals should establish a new treatment guideline to conduct early intensive surgery on the disease instead of just observing the disease even if it shows no symptoms. "A Korean doctor has solved a controversial and difficult cardiology problem where there were no clear standards or treatment," the hospital said.
Asymptomatic aortic stenosis is the most common cardiac valve disease. It is a representative chronic disease with increasing prevalence as the population ages. In severe asymptomatic aortic stenosis, aortic valve replacement is known as the most effective standard of care.
One-third of patients with severe asymptomatic aortic stenosis show no prevalent symptoms, and most of them detect the disease unexpectedly while undergoing physical examinations, such as echocardiography.
Until recently, even if doctors diagnosed a patient with asymptomatic aortic stenosis, doctors had opted to observe the patient without any special treatment and to replace the aortic valve only if symptoms occur. That was in part because there was no definite criterion as to whether it was beneficial to observe the patient or to perform the surgery, which can increase the risk on patients that showed no particular symptoms.
Professor Kang observed 145 patients who showed signs of asymptomatic aortic stenosis but showed no particular symptoms from July 2010 to April 2015. Of the total 145, 72 were kept on observational treatment, and the other 73 underwent early surgery within two months of their diagnosis.
As a result, the primary evaluation criteria of surgical mortality or cardiovascular mortality for patients who underwent early surgery was 1.4 percent, which was much lower than that of the patients who were kept on observational treatment (15.3 percent).
Also, the average mortality rate of all causes was 6.8 percent in the early surgery group and 20.8 percent in the observational treatment group, while the incidence of sudden death in the observational treatment group was 4.2 percent within four years after diagnosis and 14.2 percent within eight years.
"The study showed that in asymptomatic severe aortic stenosis, whose valve inlet narrowed to less than 0.75 square centimeters, mortality could be significantly reduced by early surgery within two months compared to observational treatment," Professor Kang said. "The publication of this research in the NEJM suggests that it is the best treatment method for patients with asymptomatic aortic stenosis."
It is essential not to overlook the symptoms if a patient has been diagnosed with asymptomatic aortic stenosis through echocardiography, Kang added.
The AMC professor published his first study, "Early surgery versus conventional treatment for infective endocarditis," in NEJM in 2012.