"We Can Save Even a Baby This Small"... 356-Gram Preemie Successfully Undergoes Aortic Procedure in Japan

Believed to be the lowest-weight patient worldwide to undergo aortic stenting
Stent placed in a 1.2-mm aorta at 19 days old
At 11 months, weighs 4.9 kg... growing with her own blood vessels

An extremely premature infant weighing 356 grams has drawn attention after recovering from a cardiovascular procedure.

A 356-gram extremely premature infant in Japan recovered after undergoing a cardiovascular procedure. Shizuoka Prefectural Children's Hospital.

According to the Asahi Shimbun and other outlets on October 20, Shizuoka Prefectural Children's Hospital announced on October 19 that it had successfully performed a procedure to widen a blood vessel in a baby girl born with a narrowed section of the aorta. The baby weighed 356 grams at the time of the procedure. The hospital said, "Among reported cases in which the same treatment has been successful, this appears to be the lowest weight in the world, far below the previous record of 590 grams."

Too fragile to withstand surgery... An adult stent in a 1.2-mm aorta

The baby was born by emergency cesarean section in October 2025, at 25 weeks and 3 days of pregnancy. Born about 15 weeks before her due date, she was small enough to fit in one hand and had to rely on a ventilator. After birth, she was diagnosed with coarctation of the aorta, a congenital condition in which part of the aorta, which carries blood from the heart to the rest of the body, is narrowed and blood cannot flow properly. The usual treatment is to remove the narrowed section and reconnect the blood vessel, but in babies born so prematurely, the vessels are fragile and difficult to stitch, and they may not be able to withstand the surgery itself. The medical team therefore decided to postpone surgery and first widen the narrowed vessel to give the baby time to grow.

The team used a catheter procedure. A thin tube, or catheter, is inserted into a blood vessel, and a stent made of metal mesh is placed in the narrowed section to widen the vessel. On the baby's 19th day of life, the medical team inserted the catheter through a blood vessel in her neck, about 1 mm in diameter, and positioned a stent in her aorta, which was only 1.2 mm in diameter. The procedure was reportedly so risky that a failed attempt could have ruptured the aorta and been fatal.

Akane Shibuya, deputy head of the cardiology department and the baby's attending physician, said, "There are no stents made specifically for children, so we used a standard stent intended for treating coronary arteries in adults, such as in cases of myocardial infarction." The hospital said, "Our experience performing the same treatment on low-birth-weight babies 10 times before contributed to this success."

Growing to 4.9 kg... "Hope that even tiny babies can be saved"

The baby grew steadily. At 5 months old, when she weighed 2.3 kg, she underwent another procedure to widen the stent. She was discharged from the hospital at 7 months old. When she reached 4.9 kg at 11 months old, the medical team performed the surgery they had postponed. They removed the stent and the narrowed section of the blood vessel, then directly joined the baby's own blood vessels. The baby can now grow using only her own blood vessels, without any artificial devices, the hospital said.

Kijiro Sakamoto, director of Shizuoka Prefectural Children's Hospital, said, "I think this is one way of sharing the message that a children's hospital can offer tremendous support." Deputy Department Head Shibuya said, "Now that we have confirmed that even a baby this small can be saved, this will bring great hope to babies with similar conditions and their families." The baby's parents said, "We were anxious when we were told the chances of success were not high, but we were relieved that everything went well. We hope our child's case will help other children and medical teams."

In South Korea, a team led by Professor Kim Woong-han of the Department of Pediatric and Thoracic Surgery at Seoul National University Children's Hospital has saved a baby with coarctation of the aorta who was born weighing 590 grams at 31 weeks of pregnancy. The medical team waited for the baby to grow to more than 1 kg so the baby could withstand surgery, then opened the chest and performed a five-hour operation when the baby was 46 days old and weighed 1,110 grams. The case is known as the lowest-weight baby in South Korea to have undergone heart surgery.

This content was produced with the assistance of AI translation services.