In late summer and into the fall, Marijke Ameigh watched with excitement, impatience, and a little discomfort as her body slowly grew its own replacement part.
The lump near the 16-year-old’s abdomen and a tiny port close to her rib cage were the only external evidence of the unusual experiment inside her.
Ameigh is the third person to undergo a surgical procedure being pioneered at Boston Children’s Hospital in which a child’s blood vessels are stretched, providing new material to make repairs elsewhere in the body. The newly grown arteries can replace sections that are damaged or missing, resulting in fixes that may grow with the child and last a lifetime.
In Ameigh’s case, she and her doctors hope the new tissue will help her keep up with classmates, walk without pain, and — most critically to a teenager — dance at the winter formal.
The artery-stretching technique was described in a letter published in December in the New England Journal of Medicine. Surgeons implant a device that, when filled with fluid, expands like a balloon behind a healthy artery.
‘If you can refashion your own tissue inside, your body is the best incubator.’
Ameigh is a precocious 16-year-old who was missing much of the artery that branched to feed her left leg with blood.
The balloon device, which Ameigh nicknamed Edna, was implanted near her abdomen for nearly half a year to grow several extra inches of blood vessel, the most of any patient so far. In November, the artery was transplanted to connect vessels in her leg, and today, Ameigh is back to walking around, taking it easy at home in North Hero, Vt. The leg feels stronger every day.
“Obviously, we’re always looking for the 70-year solution,” said one of her Children’s Hospital doctors, Dr. Heung Bae Kim. “If you can refashion your own tissue inside, your body is the best incubator.”
Kim was inspired by a sight that would be familiar to many surgeons. When removing a large tumor from a pediatric patient, he took note that a blood vessel that delivers blood to the kidney stretched quite long — four to five times as long as normal. As the tumor had grown, so had the blood vessel. But it wasn’t like a rubber band that had just stretched; the artery had grown around the tumor.
Kim realized that if children with rare disorders that cause arteries to be damaged or missing could be induced to grow extra lengths of blood vessel, it would simply be a matter of plumbing for surgeons to use that extra artery to make repairs. Unlike artificial materials that are often used as replacements and are outgrown, patients’ own tissue offered the prospect of a one-time fix. If it worked, perhaps the technique could be extended to stretch and grow other types of tissue — intestine or esophagus.
The problem was one that most doctors had never pondered: how to safely emulate one aspect of a tumor in a child. The solution lay in a technique used in plastic surgery to stretch the skin — a tissueexpander, often used, for example, in breast reconstruction. Kim and his team decided they would use the small device to stretch a healthy length of artery.
In July 2010, Kim’s first patient was a 3-year-old girl born with midaortic syndrome, a rare condition that causes the aorta, a main conduit for blood, to narrow dangerously. Such children have extremely high blood pressure, putting them at risk of strokes.
The Children’s Hospital team placed the tissue expander near a section of healthy aorta in the abdominal region and gradually filled the device with fluid to stretch a link of aorta just below the area that was dangerously thin. Then, they removed the narrowed section of artery and pulled up the healthy artery to bridge the gap. As Kim and his team reported in the New England Journal of Medicine, the child is doing well 16 months after the procedure, and her blood pressure is controlled with two medications.
Dr. James O’Neill, professor of surgery at Vanderbilt University School of Medicine in Nashville, who was not involved in the operation, said he has great respect for the team that did the procedure, and that there were good reasons for trying the experimental approach. Ultimately, he said, whether it catches on will depend on how patients fare over years.
“It is innovative. It is creative. And if on longer-term follow-up it works, it may be a solution for a very young child who couldn’t be controlled on conventional medications,” O’Neill said. “I would certainly like to see much more proof.”
Kim’s team this year did the same procedure in a second child with the same condition. So far, the procedures have been covered by insurance.
Then, Ameigh showed up at the hospital with a problem of a different magnitude. She was born with congenital heart disease. The procedures that saved her life as an infant — threading wires up through the artery near her groin to reach her heart — destroyed the blood vessel that fed her left leg with blood. A network of spaghetti-like blood vessels grew and took over but did not deliver enough blood, making it difficult to walk even a city block without searing pain. Her left leg is about an inch shorter, and much weaker than her right.
In the young children they had previously treated, the doctors needed only a small length of extra artery to make the fix — about 1.5 inches. But they needed to grow about four times that for Ameigh, pushing the limits of what they’d done.
Ameigh watched a slide show from the doctors about the procedure. It sounded scary, but she “got her bravery on,” said her mother, Myra Ameigh. In July, the doctors implanted the tissue expander and began the process of slowly filling it with blue fluid.
The 16-year-old kept a sense of humor the whole time. When the tissue expander got bigger initially, it caused pain, and she told her friends, “Edna’s feeling really bad today.” She was amused when her surgeons’ eyes grew wide, “like kids in a candy store,” when looking at a medical scan that showed how much extra artery she was able to grow.
In late November, she went in for surgery that lasted more than 12 hours. Doctors were able to stretch about one-third of the needed length, but found other ways to bridge the rest of the gap. When Ameigh woke up, her first groggy question was, “Mom, is Edna gone?” Myra Ameigh recalled.
Now her parents and doctors are waiting to see what happens in the coming weeks and months. Even in the days after the surgery, Ameigh’s leg felt a bit different, she said. Her foot felt a little warmer.