My Pet World: Heart disease a bigger issue for cats than previously thought

The effects of heart disease in cats can be more devastating than veterinarians previously thought.

Based on his studies, veterinary cardiologist Dr. Philip Fox, of the Animal Medical Center in New York City, says that cats diagnosed with feline hypertrophic cardiomyopathy (HCM) face a 1-in-5 chance of developing either heart failure or blood clots, both of which can be fatal.

"It's a real eye opener," Fox said.

With funding from the non-profits Winn Feline Foundation and the Morris Animal Foundation, Fox enlisted veterinary colleagues from 20 countries to follow over 1,700 individual cats, from 2005 to 2012. Each cat was tracked for five years following an initial definitive diagnosis of HCM.

"To my knowledge, this has been the largest and most comprehensive study ever to investigate any cat disease," Fox said. He revealed the results of the study at the 36th Annual Winn Feline Foundation Symposium, held June 26 at the Sheraton New Orleans.

Having published many papers in his 30-year career, Fox says these findings are particularly important.

"For the first time, we understand the magnitude of the problem, which is more than I would have anticipated it would be," he noted.

The news is especially bad for cats with HCM who will suffer a blood clot, or develop an aortic thromboembolism when a clot breaks loose from the heart and becomes lodged at the end of the aorta, causing the blood flow to the hind legs to stop. Cats suffering from aortic thromboembolism suddenly become paralyzed on their hind legs or have difficulty walking, and typically suffer from agonizing pain.

"Survival of cats that throw a blood clot to the rear legs is very poor," Fox says. "When this happens, the majority of these animals die or are euthanized due to medical complications of this condition, or due to the painful state it induces."

Cats diagnosed with HCM who later suffer from heart failure may actually have a better outcome than those who develop blood clots. At least there is some hope with proper treatment.

"I think it's important to point out that at least some cats with heart failure survive and never look back," Fox adds.

Of course, the best scenario is that nothing happens after a cat is diagnosed with HCM? In fact, many cats with HCM do live out a normal lifespan, ultimately succumbing to an unrelated problem.

One drawback of Fox's study is that cats were only followed for five years, so he and his team never looked at HCM's impact on longevity.

"Approximately four out of five cats remained asymptomatic (at least over five years), but one would expect that a proportion of these animals might still develop complications from HCM later on," Fox says.

Regular veterinary visits for all cats are a good idea, increasing the odds of early diagnosis, which is always helpful. Cats most at risk might also benefit from the CardioPet ProBNP test, an inexpensive blood test which can offer clues to the veterinarian before jumping to the far more expensive gold standard test: an echocardiogram.

The Winn Feline Foundation, which raises money to fund cat health research, has supported many studies on HCM since initiating the Ricky Fund. Named for my Devon Rex cat, Ricky, who died of HCM in 2002, the fund has raised over $100,000.

Backed by Winn funding, a gene defect causing HCM was discovered in Maine Coon and Ragdoll cats, which can determine if this form of heart disease might be passed on to the next generation via an inexpensive cheek swab test. Without question, lives have been saved.

"Of course, more needs to be done," Fox adds. Learn more about the foundation at www.winnfelinehealth.org.

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