Seoul National University Hospital (SNUH) announced Tuesday that it has developed an index that predicts the prognosis of patients with aortic valve stenosis, which is a type of heart disease, by using magnetic resonance imaging (MRI).

Aortic valve stenosis is a disease, in which the heart is not able to deliver blood efficiently due to the narrowing of the aortic valve, which acts as a gate between the left ventricle and the aorta. Such defect makes the heart contract more strongly to deliver blood to the narrow valve septum, and over time, the heart muscle becomes hypertrophied by fibrosis. If symptoms intensify, it may cause difficulty in breathing, chest pain, syncope, and sudden death.

Professors Lee Seung-pyo and Lee Hee-sun

The research team, led by Professors Lee Seung-pyo and Lee Hee-sun of the department of cardiology at the hospital, applied the “T1 mapping” method to the heart MRI of 127 patients with aortic valve stenosis who visited SNUH between 2011 and 2015. The team then measured the myocardial T1 value during a follow-up, which lasted for an average of 30 months.

MRI is a device that acquires images by measuring magnetic waves coming back from the human body when it forms a strong magnetic field. The time of return of the magnetic wave increases when the condition of the surrounding tissues has flaws such as fibrosis, inflammation, and infarction.

T1 value is the time that measures the return of the magnetic wave, while T1 mapping refers to the image represented by a color in regards to the T1 value.

As a result, patients who had a higher the myocardial T1 value had a worse prognosis compared to those who had low T1 values. Nearly 43 percent of the patients with the highest values experienced emergency hospitalization due to death and deterioration of heart failure, while those in the lowest bracket only had a ratio of 2.4 percent.

Also, the researchers found that they could predict postoperative outcomes by analyzing the risk factors for known aortic stenosis, such as age, symptom status, and myocardial damage, as well as myocardial T1 value.

Further analysis of the 87 patients, who underwent surgery for aortic valve replacement, showed that four patients with the highest preoperative myocardial T1 value had experienced emergency hospitalization after surgery due to death and deterioration of heart failure. There were no cases of such admission in the group with the lowest or middle T1 value.

“Aortic valve stenosis should be managed with careful consideration of the condition and progression of the disease, symptoms of the patient, as well as any other accompanying diseases,” Professor Lee said. “Since the study enables prediction of prognosis beforehand, we expect it to be of great help in the treatment of the illness.”

Professor Lee Hee-sun also urged patients to seek immediate medical care if they suspect aortic valve stenosis symptoms.

“Degenerative disease is known to be the most common cause of aortic valve stenosis, and it is not easy to prevent it. With the society aging, patients suffering from the illness are likely to increase,” she said. “If symptoms such as chest pain, dyspnea, throbbing, and syncope are present, do not hesitate to call a cardiologist and get an accurate diagnosis.”

The results of the research were published in the JACC Cardiovasc Imaging, a magazine affiliated with the American Heart Association.

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