Seoul National University Children's Hospital said Friday that it has completed an aortic constriction surgery on a premature, lightest newborn in the nation.

The infant, who was born 31 weeks into the mother's pregnancy, had a weight of 590 grams and a height of 30.5 centimeters and suffered from coarctation of the aorta, which is congenital heart disease, from birth. Coarctation of the aorta is a disease in which the aorta narrows, and blood does not flow well under the chest.

"The baby was in a dangerous condition upon birth. We had to open the arterial duct by administering a Prostaglandin E1 (PGE1) so that the blood could reach the whole body," the hospital said. "His symptoms also came as a burden to his heart, and we had to use diuretics and blood pressure medications to treat some of the issues."

While the need for an operation was urgent, the hospital's hands were tied as they could not operate on a baby weighing so little. The medical staff's primary goal was to increase the baby's weight as quickly as possible to a kilogram so that he could safely receive the surgery.

However, the process was not as smooth as the baby's intestine was not working properly. Therefore, the hospital had to conduct a contrast enema method to remove the problem, and the patient weighed one kilogram. Soon after that, the hospital decided to operate on the baby as his aortic constriction gradually narrowed, and hypertension continued.

"Aortic constriction surgery is known to be the most difficult operation in the field of cardiac surgery to be performed on a baby with a very low birth weight of less than 1.2 kilograms," the hospital said. "This is because the heart must be stopped and the blood needs to be circulated outside of the patient's body with the atrium or ventricles exposed."

The patient also needed an artificial cardiopulmonary device to supply oxygen, the hospital added.

Despite such hardship, Professor Kim Woong-han and his team successfully conducted the surgery on the baby's heart, which was only three centimeters long and wide. It showed no complications after the surgery. The baby had the lightest weight among patients that have undergone the aortic constriction surgery.

The hospital plans to discharge the baby as his recovery process has been smooth.

"It is meaningful that the baby, who weighed only 1.1 kilograms, will grow healthy without any complications," Professor Kim said. "The surgery is also significant as it shows any disease is curable if patients do not give up."