For the first time, a pediatric interventional cardiologist from Boston Children’s Hospital scrubbed in for surgery at Henry and Lois Foster Hospital for Small Animals (FHSA) at Cummings School of Veterinary Medicine at Tufts University to treat an American Eskimo Dog named Azuki with an extremely rare form of congenital heart disease.
“For congenital heart disease, there are a lot of parallels between animals and humans,” says Dr. I-Jung Bernard Chi, assistant professor of cardiology in the Department of Small Animal Clinical Sciences at Cummings School. “We speak a very similar language to pediatric cardiologists when it comes to congenital heart diseases.”
Chi determined that Azuki’s condition required a surgery not reported in veterinary medicine, so we asked Dr. Michael Farias, associate cardiologist at Boston Children’s Hospital and assistant professor of pediatrics at Harvard Medical School, to lend his expertise. Farias has performed this type of surgery in babies and agreed to take on this case with Chi—his first animal heart surgery.
“Incredible kudos to Dr. Chi and team for reaching out. Not every team would be as creative in their thinking in offering this to this dog and his family and reaching out to a team that does have this expertise, albeit in a different mammal. It was exciting to participate. I love the idea of collaboration, what different fields can teach and learn from each other. I’m glad we were able to succeed together,” says Farias.
Azuki was born at FHSA, the last and tiniest of eight dogs in the litter. He was less energetic than his siblings and often became cyanotic (having blue discoloration due to low blood oxygen levels) when playing or exercising.
Last fall, when Azuki was three years old, his stomach became enlarged. An ER clinician at a nearby animal hospital told his owner that Azuki’s heart disease had become so severe that fluid was leaking into his abdomen, and the dog had only a few months to live.
Azuki returned to FHSA to see cardiologist Dr. Vicky Yang, associate professor in the Department of Small Animal Clinical Sciences at Cummings School. Yang pulled in Chi for his specialization in diagnosing and treating congenital heart disease.
Critical to Azuki’s diagnosis and treatment planning was a comprehensive assessment of his condition using cardiac computed tomography (CT). Cummings School has the only scanner of this kind in New England. The scanner’s cardiac gating technology takes images at specific intervals during the heartbeat to eliminate blurring, enabling clinicians to conduct a full cardiac study.
“For a complex disease like this, it has to be a cardiac study to get the information you need to diagnose and plan for intervention,” says Chi. “Cummings School is the place to come for complex heart diseases—whether it’s congenital or acquired. We have the full capability from advanced diagnostics to intervention.”
Chi and Yang diagnosed Azuki with pulmonary atresia with intact ventricular septum, an extremely rare form of congenital heart disease. The right side of Azuki’s heart had no outflow and could not deliver blood to the lungs. Since the pulmonary valve had no opening at all, high pressure developed within the right side of the heart, causing fluid leakage into the abdomen. The only viable pathway of blood flow was to shunt through a hole between the two atriums (foramen ovale) to the left side of the heart (thus causing his cyanosis). He remains to have a small neonatal vascular connection between the aorta and pulmonary artery (ductus arteriosus) and developed collateral vessels (major aortopulmonary collateral arteries) to deliver blood flow from the aorta to the lungs. The cardiac CT showed the full intricate complexity of his heart disease.
Chi considered a surgery for babies and children suffering from this condition to be the best option for Azuki, to decompress the right side of his heart, improve function, minimize fluid in his abdomen, and relieve his cyanosis. He discussed the risks with Azuki’s owner, who opted to proceed in hopes of improving Azuki’s quality of life. Chi consulted with a pediatric interventional cardiologist, Dr. Dennis Kim at Emory University, who recommended he contact Farias.
Farias is one of six pediatric cardiac interventionalists at Boston Children’s Hospital, specializing in cardiac catheterizations and minimally invasive diagnostic and therapeutic options for heart disease. Farias and Chi met previously when Chi visited Children’s Hospital to observe pediatric cardiac procedures.
The six-hour surgery took place last March. Farias and Chi used a special type of guidewire, as thin as a hair, to puncture through the pulmonary valve membrane that had no opening. They planned to push the wire through the valve and inflate a balloon catheter over the guidewire to open it. With such a tiny, underdeveloped ventricle, the procedure was quite technically difficult even to get the catheter close to the valve, while also not puncturing another area of the heart.
“When we treat this disease in babies, they’re usually one, two, three days old. The tissues are softer; they haven’t had as much time to get fibrotic or thicken. This dog is three years old, so the tissue was more thickened, and it was challenging to cross the valve,” says Farias.
For a complex disease like this, it has to be a cardiac study to get the information you need to diagnose and plan for intervention. Cummings School is the place to come for complex heart diseases—whether it’s congenital or acquired. We have the full capability from advanced diagnostics to intervention.
Several times over the first few hours, Farias and Chi reset and attempted new approaches to reach the valve, but the valve membrane proved too tight for the balloon catheter to advance. They decided to approach the valve from both sides—putting a snare catheter through the aorta and ductus arteriosus into the pulmonary artery. With catheters now on each side of the valve, they used guidewire to puncture through the valve, grasped the guidewire on the other end with a snare, and pulled the balloon catheter through the valve.
“What was extremely helpful for me was to have Michael by my side to bounce ideas inside the OR. I was really happy that it eventually worked out,” says Chi. “If Michael wasn't there, this couldn't have happened—because of his expertise and his experience with this very complex disease in children and babies. I also want to give a huge round of applause to all the people involved in Azuki’s care—my colleagues, Drs. Vicky Yang and Hannah Melhorn, cardiology residents Drs. Allison Mosichuk and Taylor Reiter, our cardiology technicians Kelsey Weeks, Alyssa Luce, and Michelle Maillet, and the entire Anesthesia team for their tenacity throughout the entire procedure.”
“We collaborated well. We shared a common language we understood. It was satisfying to be on a team that wouldn’t give up and to see the acute improvement in the dog,” says Farias.
Azuki recovered smoothly and has since moved back to China with his owner, who reports that his energy has improved markedly over the months after his surgery. He is more playful and no longer cyanotic. Fluid still collects in his abdomen, but at a much slower rate and in smaller volumes. Chi hopes that will continue to improve.
Farias is also happy with the outcome of his first canine patient, “It was really satisfying to help this dog and succeed in this case. The next day I walked into work, and everybody kept asking me, ‘Did you really cath [catheterize] a dog?’ It was uplifting for the Boston Children’s team that our expertise extends to all kinds of animals, not just human ones.”