Mending broken hearts in dogs

Canine mitral valve repair surgery comes to U.S.

February 14, 2019 (published)
By Kim Campbell Thornton

Dog owners in North America seeking mitral valve repair surgery for their pets soon will have an alternative to traveling overseas for the intricate and expensive cardiac operation.

In April, the University of Florida College of Veterinary Medicine is starting an open-heart surgery program for dogs, becoming the first in the United States to offer mitral valve repair.

At the outset, the surgery will be performed by, in collaboration with and under the instruction of Dr. Masami Uechi, a veterinary cardiologist. Uechi perfected the complex technique at his practice, Japan Animal Specialty Medical Institute Inc. (JASMINE) Veterinary Cardiovascular Medical Center in Yokohama, Japan.

At UF, the cost per patient is estimated to be $45,000. Nevertheless, the waiting list already is more than 80 dogs long.

Nearly 2,000 dog owners have obtained, are seeking or are considering the surgical fix, judging from the size of an online community called Mighty Hearts that advocates for surgical treatment of canine mitral valve disease (MVD).

About one in 10 dogs develops heart disease. Of those, the large majority — approximately 75 percent — have degenerated mitral valves.

The mitral valve is one of four valves in the heart. Healthy valves open and close in time with the heart's pumping action. Sometimes, valves don't work properly; they fail to open fully or they leak when closed, or both.

In patients with MVD, a weak mitral valve allows blood to flow backward, or regurgitate, from the lower left chamber (the left ventricle) to the upper left chamber (the left atrium). To compensate, the heart muscle works harder and grows larger, which can increase pressure on the organ and result in fluid buildup.

The condition can be managed with medication, but only temporarily. Dogs with MVD end up with congestive heart failure — a buildup of fluid in the lungs and elsewhere in the body — and might live only nine months to a year.

Canine MVD primarily affects small dogs 10 years and older, but some breeds, including cavalier King Charles spaniels, Chihuahuas, dachshunds and Maltese, are prone to the condition and may become ill much younger.

In humans, mitral valve disease routinely is cured surgically. For dogs, surgery has become an option only recently. Uechi pioneered the technique in dogs in 2006. Since then, he has performed more than 700 such operations. Today, canine mitral valve repair surgeries are available in France and England, in addition to Japan.

In the United States, UF plans a clinical, teaching and research partnership with Uechi for the next three to five years. The program involves Uechi and his team visiting Florida every two months to do six cases, at the same time training UF veterinarians and surgical team members in the technique.

"Rather than reinventing the wheel and going through the process of learning it ourselves from scratch with the mortality rate that would involve, it just made so much sense to me to bring him over so he can train us and teach us, and his team can teach us, how to do this procedure successfully," said Dr. Simon Swift, a clinical associate professor and chief of the cardiology service at UF’s Small Animal Hospital.

Uechi has a surgery success rate of greater than 90 percent, according to UF.

Repairing the mitral valve in dogs entails rebuilding the deformed valve with a ring made of a special plastic to improve the orifice, and replacing the chords that hold the valve leaflets, or flaps, in place. The procedure requires stopping the patient's heart and providing life support with a cardiopulmonary bypass machine.

"Obviously, there are some risks," said Dr. Mark Kittleson, a veterinary cardiologist and professor emeritus of the University of California, Davis, School of Veterinary Medicine. Kittleson has traveled to Japan to observe the procedure. "It hasn’t achieved the same success rate they have in humans, where the mortality rate is closer to 1 percent, but it is still very impressive and unmatched in veterinary medicine," he said.

Kittleson explained that cardiopulmonary bypass and mitral valve repair in dogs is performed primarily in small dogs, which makes it inherently somewhat more difficult than in adult humans. But that is not the main reason open-heart surgery has not to date been as successful in veterinary medicine as it is in human medicine, he said.

"The major reasons open-heart surgery is successful in humans are surgical training and repetition," Kittleson said. "A human cardiovascular surgeon undergoes at least 10 years of training, many under the direct supervision of a cardiovascular surgeon, and once doing procedures on her or his own, can only maintain competency by doing surgery often — at least 200 surgeries a year. So most human surgeons trained in the procedure perform it daily," he said. “It’s a matter of doing it, doing it often and having a good team.”

He noted that Uechi, like other veterinary pioneers in open-heart surgery, trained himself. "However, he is the first one to leave the confines of a university hospital and set up a private facility devoted strictly to doing mitral valve repair," Kittleson said. "And so, he is the first one ever to mimic a human cardiac surgery program and do surgery every day."

Beyond surgical training and repetition, there also are differences in human and canine physiology. One obstacle in the development and availability of the procedure in dogs has been an increased risk of blood clots arising from cardiac bypass, according to Dr. Michael Aherne, a clinical assistant professor of cardiology at the UF College of Veterinary Medicine. "It seems to be associated with some inherent species-specific differences, as these complications are not encountered as frequently in humans," Aherne said.

However, Uechi's growing experience with the delicate procedure appears to be paying off. "Over a number of years, Dr. Uechi has refined his technique for placing dogs onto and off of cardiac bypass, as well as the surgical repair technique itself, such that he and his institute have the best success rates with mitral valve repair surgery in dogs, with fewer bypass-related and surgical-related complications," Aherne said. "It is therefore becoming a more viable treatment option for degenerative mitral valve disease."

University of Florida thought long and hard before committing

Bringing the program to UF took years. One key task was persuading the university administration to support it financially and to accept the likelihood of failures in the early stages while the team gains experience. In the end, according to a UF spokesperson, the university chose to invest in the program, with the help of private donations, because it recognized an unmet need of clients seeking this type of surgical treatment for their dogs. The university expects the program ultimately to pay for itself.

The estimated surgery price of $45,000 is greater than that of existing programs, reflecting UF's start-up costs — equipment purchases alone approach $500,000 — and the expense of flying the Japanese team to Florida.

Swift declined to specify the program's cost and fundraising goals, saying, "While my administration is unwilling to divulge the financial details of the program, as you can imagine, it is significant, and we are looking for further donations for start-up and ongoing costs."

Photo by Shanna Reynolds
JoJo's owner applied to the University of Florida open-heart surgery program but, concerned that the sick 11-year-old Chihuahua couldn't wait, she took him to England, where he is scheduled for surgery at the Royal Veterinary College in London on Monday.

The program requires cardiology, anesthesia and critical-care faculty who can triage cases, run the anesthesia and care for patients around-the-clock in the ICU during recovery. The program also requires personnel skilled in operating the heart-lung machine.

Swift said one faculty member will learn the actual surgical procedure, while other faculty members will learn the other aspects. He noted that the surgeon likely will require more training than will be available from Uechi's bimonthly visits. "We're probably going to have to send our surgeon over to Japan to take part in the procedures over there to make sure that we can get him taught in a sufficient period of time, and so, obviously, there's costs involved in that," Swift said.

For its April debut, the program has more than 80 patients on a waiting list to choose from. The first have yet to be selected; Swift said they will be the patients most in need, such as dogs who have had an episode of heart failure. "They have a much more limited time compared to those dogs who just have heart enlargement," he said.

Swift said the goal for the first year is 21 to 26 cases, working in time up to 48 per year.

To be a candidate for the UF program, a dog must be under the care of a veterinary cardiologist and have radiographic or echocardiographic evidence of left-sided heart enlargement; or past or current clinical signs of congestive heart failure.

Required diagnostic tests to determine eligibility are an echocardiogram, chest radiographs and an electrocardiogram. The UF program might also request an abdominal ultrasound by an internist or radiologist, a complete blood workup, urinalysis, coagulation profiles, and blood typing. Dogs must be current on rabies and DA2PP (distemper, adenovirus-2, parainfluenza and parvovirus) vaccinations. The patient’s cardiologist can perform necessary examinations and testing. Dogs who are chosen will be assessed by the UF team prior to surgery.

Dog owners hedging their options

Up until now, North Americans who wanted their dogs to have mitral valve repair have had to take them overseas. For a time, Uechi and team traveled to Clinique Veterinaire Bozon in Versailles, France, for one week every other month, teaming up with two veterinarians there, Dr. Jean-Hugues Bozon and Dr. Sabine Bozon, to perform up to five surgeries per visit. A trickle of people willing and able to take their dogs to Europe turned into a flood, and the French clinic became overwhelmed, amassing a months-long waiting list.

North American owners then began seeking the surgery in Japan, where Uechi performs it daily, and at lower cost — $17,000 to $18,000, compared with $40,000 in France — since he doesn’t have to fly his surgical team and equipment halfway around the world.

One owner who traveled to Japan is Ashley Grimes-Brown, a veterinary assistant in Bella Vista, Arkansas. When her dog Riggs, a cavalier King Charles spaniel, developed congestive heart failure, Grimes-Brown started researching options to save his life.

No regrets

One cardiologist offhandedly mentioned the surgery in France but dismissed it because of the cost. But Grimes-Brown was intrigued. She read an article about someone who had taken her dog to France. Then she found her way to the Mighty Hearts online community. In the end, she opted to take Riggs to Japan.

"We just hoped and prayed he would make the quarantine time, and he did," she said.

Taking dogs to Japan requires seven months of preparation before travel because of the country’s strict entry requirements. Not every dog can wait that long, so availability of the procedure in the U.S. has interested owners cheering. However, the cost and the long waiting list also has them hedging their bets.

Shanna Reynolds of Grand Rapids, Michigan, sent her dog’s records to UF. She also made appointments for him at JASMINE in Yokohama and at the Royal Veterinary College in London, where Dr. Dan Brockman and Dr. Poppy Bristow, board-certified veterinary surgeons, perform the procedure.

Reynolds hasn’t heard back yet from UF, and she wasn’t able to get on the surgery schedule in Japan until May. Unwilling to risk her dog JoJo deteriorating or dying before then, she flew with the six-pound, 11-year-old Chihuahua to London this week. His operation is scheduled for Feb. 18. Surgery at RVC costs about $19,500. Airfare and lodging are extra, as is true for the other locations for anyone but local residents.

In most cases, surgery stops the disease from progressing. Dogs who undergo it typically die of non-heart-related conditions. But a trouble-free outcome isn't guaranteed.

Take Zoey. Her owner, Nate Estes of Los Angeles, took the Maltese to France for surgery in October 2016. She was 5 years old at the time. For two years, Zoey did well. Then, the left side of her heart began to enlarge.

Estes, a cofounder of Mighty Hearts, knew that Uechi’s technique had changed and improved since Zoey’s surgery. So he took her back to Uechi, this time in Japan, where Zoey underwent a second repair on Wednesday. She came out "looking very strong," Estes reported.

Second repairs historically have not been as successful as original surgeries, but the prognosis depends on the amount and type of damage, according to Estes.

In Zoey's case, it turns out that a chord had ruptured, Estes said in a post on the Mighty Hearts site. To repair the damage, surgeons approached from the right side of the heart, as scarring from the previous surgery made it impossible to go in from the left. Estes said they replaced the chord and adjusted the leaflets to minimize the severity of regurgitation.

Surgery also doesn't necessarily obviate the need for medication. Grimes-Brown’s dog Riggs, for example, still takes pimobendan, amlodipine, injectable Lasix, and torsemide, albeit at lower levels than before surgery. His cardiologist, Dr. Ryan Baumwart, an assistant professor at Oklahoma State University Center for Veterinary Health Sciences, had thought Riggs would not live long enough to make it to Japan, as the cavalier had been in end-stage heart failure. Considering that, Baumwart said, Riggs has done amazingly well, beyond expectations.

Beyond Riggs' owner, Baumwart said he has other clients who have expressed interest in mitral valve repair for their dogs. He believes the availability of a program in Florida will encourage them to do with it.

"I think there are plenty of people in the United States that would love to pursue this for their animals, and I think if you take away the added travel to a foreign country, it’s going to be much more doable for a lot of people," he said.

"It’s still a very expensive surgery and by no means does every client have the resources to spend this kind of money," Baumwart added, "but there are certain people out there just like Ashley [Grimes-Brown], who are willing to spend the money, and are willing to travel ...." By removing the hurdle of international travel, he said, UF will "likely get flooded with cases."

Would a cardiologist have the surgery performed on their own pet? Kittleson might be a case in point. He has a nearly 7-year-old cavalier King Charles spaniel who developed a systolic click two years ago, and a murmur last year — both signs of mitral valve deterioration. He’ll listen to her heart in March, her birth month, and take her for an echocardiogram.

If she reaches a stage where it looks like she needs surgery, Kittleson said, "It will get done."

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