When a patient weighs only 6.4 pounds, certain procedures can become difficult.
Such was the case with Buttercup, an 11-month-old Morkie (Maltese-Yorkie mix) who suffered from a fatal congenital heart defect. In most hospitals, Buttercup would have had to have more invasive and painful surgery to correct her condition, but the team of cardiologists at Cornell University Hospital for Animals performed an extremely unusual procedure to keep her healthiest.
Buttercup, an 11-month-old Morkie, had a common congenital heart disease that surgeons at Cornell University Hospital for Animals corrected with a rare procedure.
According to Buttercup’s owners, the little pup had a heart murmur since birth. While she had good energy at home, she would start coughing when excited or exercising. They took Buttercup to Cornell, where the team of cardiologists diagnosed her with patent ductus arteriosus (PDA), the most common congenital heart defect in dogs.
“All dogs have a ductus arteriosus (DA) in the uterus,” said Dr. Christophe Bourguignon. “It is a vessel that allows a normal supply of oxygen to the mother’s blood because she has no functioning lungs to breathe and uses the placenta to do this. A few minutes or hours after the birth, this vessel closes and the lungs can take over completely. Occasionally the DA of some dogs does not close and remains ‘patented’, hence the term PDA. “
While the DA is open, this vessel allows a large amount of blood to flow to the lungs and heart. “Most dogs will develop heart failure and die at some point,” said Bourguignon. “Drugs don’t work well, if at all.”
After Buttercup’s diagnosis was confirmed, the team of cardiologists knew they needed to act quickly.
“The vessel needs to be closed as soon as possible to prevent the complication of heart failure,” said Dr. Romain Pariaut, Associate Professor and Head of Cardiology. “This condition causes a very distinctive heart murmur that every veterinarian should detect with a stethoscope at the time of a puppy visit.”
To hold the PDA in place, doctors typically perform a catheter-based closure of the PDA, which involves inserting long catheters into a small artery in the patient’s leg and using fluoroscopy and echocardiography to guide them to the DA to view the process. Then they put a stopper in the vessel to close the hole and stop the flow of blood.
However, Buttercup was so small that this traditional method was not feasible. Her femoral artery was too small for even the smallest catheter available.
The traditional alternative to buttercup would have been a more invasive procedure in which the chest is opened and a surgeon manually closes the PDA. But Buttercup was lucky.
“The nice and unusual thing about Buttercup is that we offered to modify the catheter-based occlusion technique to access the PDA without opening your chest,” said Bourguignon.
In this modified approach, the catheter is instead passed through Buttercup’s femoral vein – which is usually slightly larger and more elastic than the artery, and has lower blood pressure and a lower risk of bleeding. “This other approach had not yet been implemented at Cornell,” said Pariaut, who had previously taken it at another institution.
This technique is much more difficult – the catheter has to be passed into and through the chambers of the heart before it can reach the pulmonary artery, and cardiologists have to use a small flexible wire to examine the wall of the artery until they find the opening of the PDA.
An added difficulty is that the hole through which clinicians have to drop the coil is much smaller and harder to aim.
The Cornell team of cardiologists began this unusual procedure in collaboration with the Anesthesia and Pain Management Service. “Without the expertise of the anesthesia team, there would be no cardiac procedure at Cornell,” said Bourguignon. “For me, the anesthetist is just as important as the cardiologist.”
With the support of Bourguignon and with the support of the cardiology technicians, Pariaut took on the main task of guiding the catheter through the femoral vein and closing the DA with the coil.
“He is a world-renowned expert in minimally invasive cardiac procedures,” said fellow cardiologist Bruce Kornreich, DVM ’92, Ph.D. ’05, Senior Extension Associate and Director of the Cornell Feline Health Center. In just under two hours, Pariaut and Bourguignon successfully closed the PDA in Buttercup.
“We were able to show that we can use this other, more complicated technique to repair PDAs in smaller patients,” said Pariaut.
After her surgery, Buttercup made a good recovery. At the time of her planned examination three months after the procedure, Dr. Lawrence Santistevan by echocardiography that the procedure was successful and the PDA was completely closed.
PDA is one of the few heart conditions that can be cured if diagnosed and treated early, Pariaut said.
“After treatment, the animals have a completely normal life,” he said. “The procedure is very safe and we can offer it to a wide variety of dog sizes. PDAs are also easy to diagnose – making sure a veterinarian is listening carefully to your pet’s heart when they have a new puppy is very important. “
Lauren Cahoon Roberts is the Assistant Director of Communications at the College of Veterinary Medicine.