February featured veterinarian: Dr. Brian Scansen, veterinary cardiologist
by Mary Guiden
Dr. Brian Scansen is a professor and service head of the cardiology and cardiac surgery section at Colorado State University. He is on the editorial board of the Journal of Veterinary Cardiology and lectures internationally on topics relevant to heart disease in animals. His clinical and research interests include congenital heart disease, advanced cardiac imaging with a particular emphasis on cardiac CT, and minimally invasive therapeutics for the heart and vasculature. Scansen recently led several sessions on heart disease in dogs and cats at WVC 2023 in Las Vegas. The team from Veterinary33 found his presentation on “Evidence-based Therapies of Heart Disease in Dogs” to be compelling and thought-provoking. Below, we share some highlights from that session.
(Note: This article provides recommendations for treatment plans from Dr. Scansen. Please either contact him with questions or refer to the studies he cited, or other veterinary manuals.)
The aim of this session was for practitioners to learn practical clinical approaches to the management of myxomatous mitral valve disease (MMVD) in dogs, based on current science. Scansen discussed new therapies and alternate strategies being developed for the treatment of heart disease and heart failure in dogs. Prior to this session, he provided two additional lectures on related topics. His sessions were sponsored by Boehringer Ingelheim.
Scansen started the session by outlining the progression of mitral valve disease in dogs. These dogs typically will have some predisposition for the disease, he said which includes most middle-aged small to medium size dogs. The animals develop a murmur as the valve changes develop, which is detected at a subclinical level. Eventually, the condition may move to congestive heart failure that may become unmanageable.
He described this progression as forming the shape of a hockey stick, with an abrupt curve that leads upward. Dogs tend to have valvular heart disease that is often asymptomatic for quite some time. Something changes and then the disease begins to progress more rapidly.
The challenge for clinicians is how to predict which dog will suffer from heart failure, and which may remain subclinical.
Mitral valve disease is common in dogs, Scansen said. According to some estimates, 10% of all dogs will develop degenerative mitral valve disease. Some will also have an enlarged heart, which puts them on the exponential growth path toward heart failure.
The left atrium is the chamber into which all the blood flows back from the lungs and into the heart. Once the left atrium enlarges the risk that the dog will die of heart diseases increases.
As a reference, Scansen shared findings from the PREDICT cohort study, which was published in 2012 in the Journal of Veterinary Cardiology. The first author is Dr. Caryn Reynolds, DVM, School of Veterinary Medicine at the University of Pennsylvania.
If chamber enlargement can predict who will go into heart failure, could we intervene earlier? This would avoid the onset of respiratory distress, emergency visits, etc. The answer based on several studies is likely "yes."
Scansen described the use of ACE inhibitors, spironolactone, furosemide and pimobendan for treating more advanced stages of heart disease in dogs. He’d like to see a study evaluating all these medications together, since it has never been conducted and most studies have evaluated only two or three drugs for heart failure at a time.
The veterinary cardiologist also said that not all dogs need an x-ray and echocardiogram as part of the diagnostic process. It’s impractical for every dog with heart disease to have an echocardiogram, he said. With an estimated 350 veterinary cardiologists in the country, it’s not practical for every cardiologist to get imaging of every dog that has this prevalent condition.
Stages of heart disease, treatment recommendations
- Stage A – dog that doesn’t have disease. No treatment.
- Stage B – dogs are asymptomatic. Don’t treat them unless we know their heart is big enough to benefit. Treatment depends on documenting that they have substantial heart enlargement that would justify the use of medication. Films or radiographs necessary. If you take a radiograph and the heart size is normal, you don’t need to push hard for an echo. X-rays can help guide what is needed to treat these dogs. If there is a question, an echo is helpful.
- Stage C – clinical signs of heart disease are present, usually respiratory in nature. There’s evidence they have pulmonary edema. In an acute setting, use FOS (furosemide, oxygen, sedation) because the animal in respiratory distress continues to be stressed unless you can break the cycle, control the stimulation causing some of the anxiety and distress.
- Stage D – standard congestive heart failure (CHF) meds at higher dosages and advanced therapeutics.
Scansen recommended accessing the Cardiac Education Group online to view case studies including radiographs. The site and radiographic viewer allow clinicians to pull up examples in various types of conditions, with the option of filtering cases by stage and specific breeds.
He introduced Dogs Are for Special People and using the acronym (DAFSP) to help guide what treatments will be beneficial for the dog in congestive heart failure. The letters stand for diet (sodium restriction), ACE inhibitor, furosemide (Lasix), spironolactone and pimobendan.
Scansen said a large study on heart failure was published last year in the Journal of Veterinary Internal Medicine. A research team led by Dr. Melissa Coffman with Ceva Animal Health found that the combination of benazepril and spironolactone is effective, safe and superior to benazepril alone, when used with furosemide for the management of mild, moderate or severe CHF caused by MMVD in dogs. This research was known as the BEnazepril Spironolactone STudy (BESST).
At the end of the presentation, Scansen acknowledged he’d referenced a fair amount of research and shared a lot of numbers.
“What is the evidence, what do we know and not know?” he asked.
With ACE inhibitors, they appear to be beneficial, he said. But at least one study shows it’s not clear if there’s an added benefit over pimobendan. Scansen said that he still gives an ACE inhibitor to every heart failure patient he treats.
Adding spironolactone or using a combination product is likely to have a benefit. Studies on pimobendan show that it is beneficial for prolonging survival and improves quality of life.
The evidence supports pimebendan, ACE inhibitors, furosemide and spironolactone.
Learn more about Dr. Scansen’s research and work in this NBC News story.
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