By Dr. Becker
Earlier in the year, a kitty named Vanilla Bean was given a second chance at life thanks to a team of veterinarians and physicians at the University of California, Davis.
Her guardians brought 1-year-old Vanilla Bean, a female Burmese who lives in Mill Valley, California, to a veterinary cardiologist because she was having breathing difficulties. The veterinary cardiologist diagnosed her with a rare congenital defect called Cor triatriatum sinister that prevents blood from flowing freely through the chambers of the heart.
The defect causes too much blood to back up in one chamber, which creates pressure and enlarges the chamber. The situation can ultimately lead to congestive heart failure, which is a buildup of fluid in the lungs and surrounding tissues.
The vet who diagnosed Vanilla Bean, Dr. Kristin MacDonald, knew of a procedure to correct the defect, but it had only been performed once, by Dr. Josh Stern at North Carolina State University.
As luck would have it, Dr. Stern had since moved from North Carolina to join the faculty at the UC Davis Veterinary Medical Teaching Hospital (VMTH).
When Vanilla Bean arrived at UC Davis, Dr. Stern and his team evaluated the severity of her condition and whether she was a good candidate for surgery, and decided she was.
A Truly Frightening Heart Defect: Cor Triatriatum Sinister
Vanilla Bean's heart, like all mammal hearts, is made up of 4 chambers. In a healthy heart, blood flows through valves between the upper chambers (the atrium) that collect blood, into the lower chambers (the ventricle) that pump blood. The valve on the left side of the heart is the mitral valve.
Vanilla Bean's heart defect was caused by an abnormal piece of tissue situated above the mitral valve that inhibited blood flow between the upper and lower chambers of the heart.
The abnormal piece of tissue was located in the center of the atrium, essentially dividing the upper chamber into two sections. In order for the blood to flow from the atrium to the ventricle, it had to travel at a faster than normal speed to get past the narrowed, thickened region created by the piece of tissue. As a result, the section of the atrium above the thickened tissue was enlarged from the increase in pressure.
If the pressure continued to build, fluid would start to back up into the kitty's lungs, and she would be in the initial stages of congestive heart failure.
Vanilla Bean's 5-Doctor Surgical Team
Vanilla Bean's particular type of congenital heart defect is also seen in children. When Dr. Stern performed the single corrective surgery at Duke University in North Carolina, he collaborated with human cardiologists.
"I needed a human cardiology team to help guide me on this case, as well," said Dr. Stern. "It's so uncommon in cats. It's uncommon in children also, but they've certainly seen more cases of this than I have."1
For Vanilla Bean's procedure, Dr. Stern sought the assistance of two pediatric cardiologists at the UC Davis Medical Center. Also on the team were a veterinary soft tissue surgeon and a veterinary cardiologist.
The goal of the 5-doctor team was to open the narrowed passageway in the cat's atrium with a hybrid cutting balloon dilatation. On larger animals, this surgery is done using catheters to access the heart. But since a cat's vessels are too small to accommodate catheters, the chest cavity must be opened and the heart exposed.
Using a technique called transesophageal echocardiography, the doctors were able to visualize the interior of Vanilla Bean's heart so that catheters and the balloon could be properly positioned. According to Dr. Stern:
"This is an extremely uncommon technique employed in veterinary medicine. It's even more rarely employed in cats due to their small size."
The balloon was placed across the defect, where it cut the membrane to permit normal blood flow.
After a Serious Surgical Setback, Vanilla Bean Is Back Home and Healthy
The procedure itself was a success, but the patient lost a lot of blood during the surgery. Fortunately, the VMTH is home to the largest veterinary blood bank in the western US, and Vanilla Bean received immediate blood transfusions.
She wasn't out of the woods yet, though, because the blood loss caused an acute kidney injury so severe the doctors were afraid she would die of kidney failure. Her creatinine levels were through the roof. Fortunately, her kidneys improved each day during her hospitalization.
Eight days after her surgery, Vanilla Bean returned home to her grateful guardians. A week later she returned to the VMTH for a check-up, and while her creatinine levels had not yet dropped into the normal range, they were continuing to come down. Tests showed the pressure in her heart had not changed since it was stabilized during surgery, which meant the balloon dilatation was successful.
Four months post-surgery, Vanilla Bean was no longer in congestive heart failure, was off all medications, and her creatinine levels had returned to normal. Dr. Stern expects her to make a complete recovery.
The medical team volunteered their time to save Vanilla Bean, making the final cost of her surgery around $3,000.