The RVC has published the results of a study which showed that dogs treated with pimobendan at the preclinical stage of mitral valve disease (MVD) remained asymptomatic for an average 15 months longer and lived for significantly longer than the placebo group.
The EPIC study (Evaluation of Pimobendan In Cardiomegaly), published open access in the Journal of Veterinary Internal Medicine1, is the largest prospective veterinary cardiology study carried out to date. The authors say that the quality of the data it produced rivals that of human clinical trials.
The study was double-blinded, placebo-controlled and randomised. It took seven years to complete and involved 360 dogs across 11 countries in four continents.
To qualify for enrolment in the study, dogs had to be 6 years of age or older, have a body weight ≥4.1 and ≤15 kg, have a characteristic systolic heart murmur of moderate to high intensity (≥ grade 3/6) with maximal intensity over the mitral area, have echocardiographic evidence of advanced MMVD defined as characteristic valvular lesions of the mitral valve apparatus, mitral regurgitation on the colour Doppler echocardiogram, and have echocardiographic evidence of left atrial and left ventricular dilatation, defined as a left atrial-to-aortic root ratio ≥ 1.6 and body weight normalized left ventricular internal diameter in diastole ≥ 1.7, in addition to radiographic evidence of cardiomegaly (vertebral heart sum > 10.5)
In fact, the study was terminated early following an interim analysis as the evidence was considered conclusive and it was deemed unethical to continue to withhold treatment from the placebo group.
Adrian Boswood, Professor of Veterinary Cardiology at the RVC (pictured above right), 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."
Adrian 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."
In light of the findings, Adrian says vets should now consider testing early for signs of preclinical MVD, and in dogs with cardiomegaly secondary to preclinical MVD, consider the use of pimobendan to delay the onset of congestive heart failure and extend the asymptomatic period.
To read more about the EPIC study and results, visit www.rvc.ac.uk
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Reinventing the wheel!
We were taught that nearly 40 years ago, then the powers that be decided there was no advantage in treating before clinical heart failure had developed. Now we've gone round in a full circle! Am I surprised?
Wynne
Certainly early enalapril etc did nothing for these preclinical cases.The advice to put whole litters of CKCS pups on the drug from an early age did the whole pre-emptive concept huge damage. This study is an adult dog with enlarged heart/affected mitral vales on u/s and with a murmur > 3 so there is a physically affected if not yet clincally affected diseased organ. And this trial used Pimobendan not Enalpril etc. I am certainly more and more impressed with this drug esp in larger breed cardiac issues-St Bern and Dobbies that would be gone in few months now living so much longer with good quality of life. The issue is the cost but now with generic available that may change our whole approach.
When I was a student, it was frusemide and digoxin! Showing my age! We were taught to start treatment as soon as a murmur was detectable. The heart was probably enlarged by then, but since nobody had ultrasound, and many practices lacked radiography, then that was difficult to ascertain. That was the view of that highly regarded cardiologist, Jimmy Holmes. The powers that be then decided to wait until the animal was in obvious heart failure. Why?
PS Pimobendan has many similarities to digitalis, but less side-effects, and, therefore a greater safety margin