The 1st Canine Open Heart Surgery in BC!

By Dr. Michael King BVSc, MS, DACVS

Specialist Small Animal Surgery

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This is the story of Taylor – one of the sweetest puppies you would ever be likely to meet, and who became the first dog to undergo open heart surgery in British Columbia.

Taylor lived the first few months of his life in Mount Currie, just outside Whistler. Due to his health problems, Taylor was surrendered by his owners to the Whistler Animals Galore (WAG) non-profit animal shelter. There, he was treated by Dr. Laura White, of Pemberton Veterinary Hospital.

Though a happy and energetic puppy, Taylor suffered from an unusual (and dramatic) buildup of excess fluid within his abdomen, a condition known as “ascites”. This made his belly appear very distended, and as well as being uncomfortable, was very detrimental to his health. Ascites is most often seen in puppies that have intestinal parasites, which Dr. White initially treated Taylor for. When that didn’t resolve his problem some diagnostic tests were performed, but an exact diagnosis was not able to be made. It was at this point last September that Dr. White and the folks at WAG got in touch with us at Canada West Veterinary Specialists.

Just as in Human Medicine, there are Specialists in the Veterinary profession. These veterinarians have gone through another 3-5 years of training focused on their one area, then taking a series of comprehensive examinations to become “Board-certified” Specialists. Canada West Veterinary Specialists is the largest such Veterinary Hospital in British Columbia, and we are fortunate to have Specialists in Surgery, Internal Medicine, Cardiology, Radiology, Critical Care, and Oncology. It took veterinarians from multiple departments working together to treat Taylor, and to successfully fix his problem.

Taylor was initially assessed by Dr. Jefferson Manens of our Internal Medicine department. His preliminary tests eliminated several common causes of ascites, and suggested that it was actually being caused by a problem with Taylor’s heart. At this point Dr. Manens consulted with Dr. Marco Margiocco, our Specialist Cardiologist.

The heart acts to pump blood to the lungs, and then around the body, via arteries and veins, to provide oxygen and nutrients to all the organs and tissues. These arteries and veins are somewhat “leaky” so you normally get a small amount of fluid moving into the different parts of the body, such as the abdomen, and then being re-absorbed. If you have too high a blood pressure in certain arteries or veins, this increases the amount of fluid that leaks out, and the body can’t keep up with absorbing it. Depending on where this pressure is occurring determines where that excess fluid builds up. Increased pressure in the large vein bringing blood from the belly back to the heart (known as the “caudal vena cava”) can cause ascites to occur. This is exactly what was happening in Taylor.

But questions still remained; What was the cause of this increased pressure? And could anything be done to fix it?

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Dr. Margiocco used an ultrasound machine to perform an “echocardiogram”. This allowed him to visualize the heart, and see the blood moving through it. Working with our Specialist Radiologist (Dr. Augustin Mareschal), he then used a CT scan to map out Taylor’s blood vessels, to look for any areas where blood flow was being obstructed. These tests determined that Taylor was suffering from a rare defect of the heart, known as “Cor Triatriatum Dexter”, or “CTD”. This is a congenital abnormality, meaning it is something Taylor was born with, and isn’t evident until it starts to cause problems like the ascites.

A dog’s heart, like a human heart, is divided into 4 different chambers – the right and left atrium, and the right and left ventricle. The blood coming from the belly first enters into the right atrium, before moving through the rest of the heart. In cases of CTD there is an unusual “membrane” that is present in the right atrium, with only a narrow opening in it. This means that blood flow from the abdomen is partially obstructed by this membrane, and causes increased pressure in the blood vessels of the belly, resulting in the ascites.

So for Taylor, this abnormal membrane in the right atrium of his heart was causing his problem. If we could remove or break down this membrane, then that would resolve his health issues, and he would go on to live a normal, active life.

The first attempt at this was doing what is called a minimally-invasive “interventional catheterization”. Using a machine called a fluoroscope (that projects a video X-ray on a screen) to guide him, Dr. Margiocco passed a catheter up one of the veins in Taylor’s leg, into the heart. The hope was to be able to place this catheter through the small opening in the membrane. Once in place, a balloon at the end of the catheter could then be inflated, to break down the membrane and restore normal blood flow. Unfortunately as the opening in the membrane was only 3 millimeters wide, this was not successful.

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The only option then to fix Taylor’s problem was with an open-heart surgery. As the name suggests, this is where surgery is performed through an incision in the heart, allowing access to remove the membrane. Open-heart surgery is commonly performed in people, but only very infrequently in dogs. It is very challenging since not only does the heart need to keep beating throughout the surgery, but the moment an incision is made into the heart, severe blood loss occurs which would rapidly cause death. To avoid this, all the blood vessels entering the heart have to first be isolated, and temporarily closed off with small tourniquets. This then allows surgery to be performed without significant blood loss. The tourniquets can only remain in place for 2-3 minutes though, before the lack of normal blood flow causes damage to organs and tissues throughout the body.

Only a few Veterinary Surgeons have ever performed an open-heart surgery in a dog, and never before in British Columbia. Dr. Margiocco consulted with one of our Specialist Surgeons, Dr. Michael King, and they discussed Taylor’s case, to see if this is something we could do at Canada West Veterinary Specialists, to help Taylor out.

Dr. Margiocco & Dr. King contacted Dr. Chris Orton – Veterinary Cardiac Surgeon at the Colorado State University Veterinary School who has done several such procedures. They discussed with him the procedure itself, and determined that this indeed was something we had the personnel and equipment necessary to perform at our Hospital. From discussions with Dr. Orton, they created a detailed anesthetic and surgical plan for Taylor.

Obviously an extensive surgery such as this gets very expensive, especially since Taylor was expected to need to stay in hospital for several days of intensive care immediately after the procedure. Though the volunteers at WAG had done some fundraising, this was not going to be able to cover the costs of the surgery, especially given the treatment that had already been done to that point. Given that Taylor should have a normal life after surgery, his wonderful demeanor, the willingness of the Shelter to work with us, and the novel nature of his condition and treatment, we wanted to do what we could to help. The Doctors and staff therefore gave their time and expertise for free, and the hospital donated materials and equipment, partly in conjunction with contributions from the Jessie Bandit Animal Care Fund. It was felt that this was an opportunity to expand the scope of the services our hospital can provide, so Taylor’s case might allow us to offer this procedure more confidently to other British Columbia pets in the future.

Once the decision was made to go ahead with the surgery, a team was put together for Taylor’s care. As well as Dr. King & Dr. Margiocco, this also included another Specialist Surgeon (Dr. Alan Kuzma), a Critical Care Specialist (Dr. Carsten Bandt), two Anesthesia technicians, and three surgical assistants. Two meetings were held before the procedure, to discuss each step of the anesthesia and surgery, and the various actions that might be needed if any complications were encountered.

On the day of surgery Taylor did remarkably well, and his anesthesia was very uneventful. The incision was made into the heart, the membrane removed, and the heart closed without any significant loss of blood. The tourniquets preventing blood flow into the heart were only in place for 1 minute and 40 seconds, and Taylor’s heart was beating completely normally throughout the procedure. Though things were obviously very tense during those couple of minutes, everyone was focused on doing their job, and communicating constantly with other members of the team. Despite everything going as smoothly as could have been hoped for, there was still a huge sense of relief when blood flow was restored, and to see normal heartbeat and pulses on the monitoring equipment.

Taylor recovered remarkably well from surgery. He was walking around happily the next day, wagging his tail, and showing a very healthy appetite. Taylor was able to be discharged back to his foster family only three days after surgery, looking like nothing had happened at all. A truly incredible patient.

Some minor medication was given for a few weeks after surgery, to help re-absorb any remaining fluid in his abdomen, and Taylor was kept on only light exercise for the first 4-weeks.
He came back to Canada West Veterinary Specialists at the end of that month for a recheck with Dr. Margiocco, who confirmed that his ascites, and abnormal blood pressure had completely resolved. He happily bounced around the hospital that day saying hello to all the staff, looking like the healthy young puppy he is!

Taylor is a wonderful dog, who made a huge impression on all of us at Canada West Veterinary Specialists, and will always be a real favorite. We will forever be grateful that he gave us the chance to make a small bit of history, and contributed to the increasing level of care we are able to offer our furry companions here in British Columbia.