Bypassing a narrowed midaorta with a living, growing graft

Midaortic syndrome is marked by narrowing of the middle section of the aorta.

By the time he arrived at Boston Children’s Hospital, the 6-month-old boy was near death from midaortic syndrome — a rare but life-threatening condition marked by narrowing of the middle section of the aorta, the largest artery in the body. It had left him with severe hypertension, acute kidney injury and heart failure. As cardiologists worked to stabilize him, the surgical team weighed the options.

With diminished blood flow to the chest, abdomen and lower limbs, a significant number of people with untreated midaortic syndrome die from complications by age 40. The condition can be treated surgically, traditionally with a prosthetic graft made from synthetic material to perform an aortic bypass. But synthetic grafts can pose a number of challenges in children.

“Synthetic grafts don’t grow with the patient, which means that multiple surgeries may be necessary through the years to ensure appropriate graft size,” explains nephrologist Michael Ferguson, MD, who was a member of this patient’s care team. “Artificial grafts also carry a higher risk of thrombosis and infection.”

Surgeons Heung Bae Kim, MD, and Khashayar Vakili, MD, of Boston Children’s Midaortic Syndrome and Renovascular Hypertension Program had developed a new treatment called TESLA, which places a tissue-expanding device behind the child’s aorta. But this technique cannot be used when a long section of aorta is narrowed. Was there another way to use the boy’s own tissue?

Innovation in the OR

During a catheterization procedure aimed at maintaining adequate blood flow to the baby’s kidneys and gastrointestinal tract, his clinicians noticed something intriguing: His meandering mesenteric artery (MMA), a large blood vessel in the intestines, had a diameter similar to that of his aorta.

Justin Kibler, first patient with midaortic syndrome to undergo MAGIC for midaortic syndrome.Justin Kibler, a competitive rodeo star, was one of the first patients to undergo MAGIC for midaortic syndrome.

“We began to wonder if we could use this specific artery as an alternative to a synthetic graft,” explains Kim. “The team got together and discussed how we might do that.”

A few months later, the child was well enough to undergo surgery — and Kim and the rest of the team used the patient’s own MMA as a living, growing graft, a first-of-its-kind procedure they termed Mesenteric Artery Growth to Improve Circulation, or MAGIC. While the boy required several additional procedures, four years later, he has improved significantly — and now only takes one blood pressure medication. Their recent paper, published in October in the Annals of Surgery, also describes a 14-year-old boy who is also thriving. In the two and a half years since surgery, his MMA graft has doubled in size, making it about the dimensions of a healthy aorta.

“Patients that are best suited for MAGIC have an enlarged collateral vessel, such as the MMA, that can be used to bypass the aortic obstruction,” explains Ferguson.

The future of midaortic surgery

Although surgeons have previously used patients’ own blood vessels as part of other bypass procedures, MAGIC is the first approach to use the MMA in place of a synthetic graft.

the meandering mesenteric artery used to bypass the aorta in midaortic syndrome
The arrow points to the meandering mesenteric artery (Gray’s Anatomy)

In total, four children have undergone MAGIC since that day in the cath lab when it was first conceived. The procedure will potentially spare them multiple future surgeries.

Even if a patient ultimately requires a synthetic graft, MAGIC doesn’t preclude that procedure. “We don’t burn bridges by doing it, but we potentially save the child from the need for a synthetic graft and accompanying risks,” says Kim. “MAGIC is the right thing to do for these kids — and even for young adults.”

The procedure, currently available only at Boston Children’s, is now offered to all eligible patients. “The children and their families are the true pioneers,” says Kim. “This was an innovation born of necessity, and we’re always pushing ourselves to do better for our patients.”