SLU news

Groundbreaking research changes the treatment of preclinical myxomatous mitral valve degeneration in dogs

Published: 28 September 2016

New research calls for vets to revaluate how they diagnose and treat myxomatous mitral valve degeneration (MMVD) to delay the onset of congestive heart failure in asymptomatic (preclinical) dogs with this common disease.

The cardiovascular drug pimobendan has shown to prolong the preclinical period with a median time of 15 month in dogs with pre-clinical MMVD, compared to placebo-treated dogs. Also, the overall survival time was extended.

- This is the greatest discovery in veterinary cardiovascular research over the last 30 years, perhaps ever, in the treatment area, says Jens Häggström from SLU, one of the researchers in the global study “Evaluation of Pimobendan in dogs with Cardiomegaly” (EPIC).

The study was terminated early after the interim analysis demonstrated an overwhelming benefit in administering pimobendan to dogs with preclinical MMVD and it was deemed to be unethical to continue to withold treatment from the placebo group. The final groundbreaking results are now presented, including strong arguments for the treatment of dogs suffering from the disease but yet not having developed signs of heart failure (ie preclinical MMVD).

The study shows that the preclinical period in dogs with MMVD and signs of cardiomegaly was extended by 15 months, which corresponded to a risk reduction of about 1/3 to reach the endpoint of the study (which was the development of congestive heart failure or cardiac-related death). The type and frequency of potential adverse side reactions did not differ between the pimobendan and placebo-treated dogs.

The magnitude of the EPIC study was unprecedented, involving 360 dogs across 11 countries in 4 continents. It is thereby the largest prospective veterinary cardiology study to have been carried out to date, pushing best practice in evidence-based veterinary medicine forward. The level of quality data in the EPIC study rivals clinical trials carried out in human medicine.

– Thanks to the EPIC study, vets no longer have to adopt a 'watch and wait' approach with suspected preclinical cases of MMVD, the research group says in a joint statement. When a typical mitral valve insufficiency heart murmur is identified, vets should now evaluate the dog further for the presence of cardiomegaly, using echocardiography and/or thoracic radiography.

The EPIC study was not designed to investigate the effect in dogs with mild MMVD without cardiomegaly, and treatment with pimobendan should be avoided in these individuals. It is thus important to examine how severe the disease is before deciding whether or not to start treatment.

Pimobendan is not yet approved by regulatory authorities in various countries for treatment of dogs with preclinical MMVD, as the final results of the EPIC study were not published until recently.

The EPIC study was designed and carried out by independent experts, led by Professor Adrian Boswood, RVC, London; UK, Professor Jens Häggström, SLU,  Uppsala, Sweden and Associate Professor Sonya Gordon, Texas A&M, USA.

The results were published in the Journal of Veterinary Internal Medicine , September 28.

Contact and more information:
Professor and principle investigator Jens Häggström
Phone: +46(0)18-67 21 24, +46(0)709-35 18 68

Pressrelease from SLU


Jens Häggström, Professor
Department of Clinical Sciences, SLU                                , 018-672124