Mochi's murmur

October 8, 2018

When a litter of 10-week-old kittens were brought into the vet for their spays and neuters, one of them, Mochi, was showing signs of a severe heart murmur. The young cat was then referred to the Veterinary Medical Center (VMC) at the University of Minnesota College of Veterinary Medicine (CVM).

After performing an echocardiogram and diagnosing Mochi with a patent ductus arteriosus (PDA), a congenital heart defect that most often presents itself in younger dogs, Chris Stauthammer, DVM, associate professor in the Department of Veterinary Clinical Sciences, performed surgery on Mochi on September 5. “PDAs are very rare in cats,” says Stauthammer. “Mochi was the fifth cat I have performed this surgery on in my fifteen years of cardiology practice.”

Mochi’s case was especially dire, too. He was suffering from heart enlargement as a result of his condition. “If we hadn’t treated him, he would have succumbed to heart failure probably within a couple of months,” Stauthammer says. “His disease was rather advanced.”

Rescued from the brink

A PDA is when a large blood vessel (ductus arteriosus) fails to close just after birth. This vessel is normal for a fetus and allows blood to bypass the lungs, since lungs are not used in utero. After birth, the vessel should close within hours so blood can be directed to newly inflated lungs. According to Stauthammer, nearly 60% of animals diagnosed with PDA die within the first year if left untreated. The remaining 40%  generally succumb to heart failure within a couple of years.

“I perform this surgery on at least five or 10 shelter or rescue animals a year,” says Stauthammer. Roughly half of those surgeries are funded by the VMC Shelter and Rescue Animal Fund, which relies on philanthropic contributions from the community. “These animals often end up in a shelter or rescue because of their heart murmurs or disease,” he says.

Many of the animals Stauthammer treats go into homes shortly after recovery. Stauthammer rescued his own dog, Squeak, from being euthanized due to her PDA, which was fixed over 10 years ago by Stauthammer. Today, she zooms across dog parks faster than most of her fellow park goers.

And the development of the Amplatz Canine Duct Occluder, a canine specific PDA device--the same device in Squeak--helped the University of Minnesota College of Veterinary Medicine’s cardiology department transform human medicine a decade ago. “It worked so well that now a modified form of it is being used in humans with the same condition,” Stauthammer says.

Just right for a cat

But the Amplatz Canine Duct Occluder could potentially cause too much clotting in cats, whose blood tends to clot a lot more easily. So Stauthammer and his team deliver a small coil to the patient through a catheter. Once placed, the coil helps cats form a clot that is just the right size to close the artery. “The coil takes a little more finesse,” says Stauthammer. “A lot of cardiologists won’t even perform the procedure.” Stauthammer lectured on the coil at the American College of Veterinary Internal Medicine Forum in June. “It was very clear that the University of Minnesota is one of the few places that will perform PDA repair on cats using the coil.”

Since surgery, Mochi’s follow up echocardiogram showed that his murmur had subsided. And he was recently adopted by Kathi Warfield of Hutchinson, Minn. “He’s remarkable,” she says, “he really bounced right back.” She got Mochi because her five-year-old female tabby seemed anxious and Warfield hoped a second cat would help. Now, she wakes up to the two cats cuddling in the morning. “He wanted so badly to be accepted by her,” she says. “He’s just a wonderful cat.”

 Photo by Martin Moen