November 2, 2016 – Researchers led by Professor Adrian Boswood of London’s Royal Veterinary College have made a breakthrough in the treatment of dogs with the most common type of canine heart disease that will significantly extend their lives.
Mitral valve disease (MVD) is caused by the deterioration of one of the heart valves and predominantly affects small breed dogs, including cavalier King Charles spaniels, dachshunds, miniature poodles, Chihuahuas and terrier breeds. Dogs with the early stages of MVD may appear normal to their owners, although a heart murmur may be detected by the vet. Heart disease is one of the top five causes of dog deaths in the UK.
The team of investigators found that giving dogs with enlarged hearts (an early warning sign of progressive heart disease), before they displayed any outward signs of the condition, the drug pimobendan, delayed the onset of heart failure by an average of 15 months.
The evidence was so conclusive, the study was terminated early as it was deemed unethical to continue to withhold treatment from the group of dogs taking the placebo.
“The main message for pet owns it that it emphasises the importance, particularly in older small breed dogs, of having their heart checked on a regular basis,” Professor Boswood told Pet News Today, adding that for dogs under seven years of age, “It doesn’t need to be more frequent than once a year.”
“The exception is cavalier King Charles spaniels, who are around 20 times more prone to this heart disease and can be affected much earlier in life, from around five years old, so need to be checked earlier and more regularly.”
“Until now the evidence tended to suggest the treatment was only beneficial after the onset of clinical signs, so that was the rationale behind taking a wait and see approach. What’s changed is that we can show that intervening in the disease’s progression while the dog is free of clinical signs makes a difference as to how long they remain free of the symptoms and those dogs who were treated ended up living longer.”
Professor Boswood said enlarged hearts are ideally diagnosed using cardiac ultrasound which requires specialist training or experience and which will not be available at every primary care veterinary practice.
Pimobendan, which is already licensed for use in dogs to treat the later stages of MVD, is relatively inexpensive. Professor Boswood said he was speaking to a client with a Cavalier King Charles spaniel recently who told him the cost of the drug was about £60 for a three-month supply for his 10kg dog. Reputable pet insurance companies are likely to cover the cost of the drug.
And Professor Boswood has more research planned.
“What I’d like to be able to do is to see whether there would be easier ways than cardiac ultrasound to identify dogs that would benefit from the treatment. It would be great if there was a tool we could put in the hands of first opinion practices… it would be even easier to roll out the recommendations that are the consequence of our findings.”
The EPIC (Evaluating Pimobendan in Cardiomegaly) study is the most robust of its kind in veterinary medicine, taking seven years to complete and working to the highest standards of clinical research, rivalling that of human trials. There were 360 dogs involved in the research, across 11 countries and four continents.
The Royal Veterinary College is ranked the world’s 3rd best veterinary school. It is pioneering the research into canine heart diseases including being one of the few centres in the world to trial heart valve surgery in dogs as a potential treatment for the disease.
Photo: Cavalier King Charles Spaniel Alfie, 13, one of the trial’s participants, with his human family Jenny Jackson, her partner Craig and their daughter Ellie, with Professor Boswood.