Scientists have made a major breakthrough in the management of myxomatous mitral valve disease (MVD), which has the potential to extend the lives of dogs throughout the world.
The “Evaluating pimobendan in cardiomegaly” (EPIC) study study sought to prove oral administration of the drug pimobendan in dogs with evidence of increased heart size secondary to MVD can delay the onset of clinical signs of congestive heart failure.
Results, published in the Journal of Veterinary Internal Medicine, showed pimobendan extended the asymptomatic period by an average of 15 months, while dogs that received the drug also lived significantly longer than those receiving a placebo.
Evidence was so conclusive, the study – involving 36 trial centres in 11 countries across 4 continents – was terminated early following an interim analysis, as it was deemed unethical to continue to withhold treatment from the placebo group.
No more ‘watch and wait’
Adrian Boswood, professor of veterinary cardiology at the RVC, led the research. He said: “Thanks to the EPIC study results, vets no longer have to adopt a ‘watch and wait’ approach to suspected preclinical cases of MVD.
“When a typical mitral valve murmur is detected, vets should now investigate further to look for cardiac enlargement. If demonstrated, this suggests the patient will probably benefit from treatment with pimobendan before the onset of clinical signs.
“It’s great that, as a trusted treatment, pimobendan has a wealth of safety data behind it in addition to that gleaned from the EPIC study, which can help support vets when prescribing it in this new way.”
EPIC is the largest prospective veterinary cardiology study carried out to date, pushing best practice in evidence-based veterinary medicine to a new level.
The prospective study was double-blinded, placebo-controlled and randomised, taking seven years to complete and involving 360 dogs across four continents.
Prof Boswood added: “As far as evidence-based medicine goes, this is about as good as it gets. The size and design of the study places it in the top tier. The study was designed and run by an independent team of investigators and sponsored by Boehringer Ingelheim. We, as lead investigators, had the right to publish the results regardless of the outcome. This makes EPIC very special indeed.”
When asked whether he thought the results were a “game changer”, Prof Boswood said: “Your words, not mine, but I’m not disagreeing with them.
“Yes, I do think it’s going to have quite a considerable impact on what future recommendations are given to clients who have animals with heart disease.
“What we’ve shown with this study is, if their hearts are big, or sufficiently big to meet the criteria for entry into our study, and they receive medication (pimobendan), they will live longer before they develop clinical signs – quite considerably longer – and then, in general, there will also be a survival benefit.”
However, he cautioned: “Something I know a lot of people will be worried about is, if vets take this message and indiscriminately administer pimobendan to every dog that looks like it’s got MVD, then, arguably, they would be over-treating.
“What the EPIC study shows is dogs with big hearts will benefit. We need vets to be looking to see if dogs with murmurs have got big hearts, whether that be by referring them to a cardiologist for an ultrasound examination or initially taking an x-ray, but what we can now do is tell owners investigating earlier may be of benefit to their dog.”
Prof Boswood praised the sterling work of the 36 specialised veterinary cardiologists participating in the EPIC study from Australia, Canada, France, Germany, Italy, Japan, the Netherlands, Spain, Sweden, the UK and the US.
He said in terms of magnitude, conduct, quality and data management, the evidence-based study compared favourably with some human med-icine studies.
Heart disease is one of the top five causes of death in UK dogs, with myxomatous MVD accounting for around 75% of cases.