Korean surgeons pull off first-ever heart valve reconstruction in dog with drug-resistant infection

A veterinary hospital in Korea has reported the "world’s first" successful surgical treatment of infective endocarditis, a rare bacterial infection of the heart valve that can be fatal, in a dog.

The procedure, performed by the cardiac surgery team at the NEL Animal Medical Foundation in Seoul, involved removing and reconstructing a damaged heart valve in an 8-year-old Spitz that had not responded to drug therapy. 

The operation used cardiopulmonary bypass, a technique that temporarily replaces the function of the heart and lungs during open-heart surgery, allowing the surgeons to repair the valve.

In a statement released Tuesday, the team said the surgery marks the first known case of a dog surviving infective endocarditis through valve reconstruction, including a rare second surgery performed after the dog developed a reinfection.

The Spitz, which weighed 6.2 kilograms, or just over 13 pounds, had previously been diagnosed with protein-losing enteropathy, a gastrointestinal disease that weakens the immune system.

It also had a history of prolonged antibiotic use, which increased its risk of developing drug-resistant infections.

In the first operation, the surgical team reconstructed the mitral valve, which had been damaged by myxomatous degeneration, a condition that causes the valve tissue to weaken and leak. The procedure significantly reduced regurgitation, and the dog recovered without the need for continued medication.

Roughly four weeks later, however, the dog developed a bacterial infection in the repaired valve. Tests confirmed it was caused by Enterococcus faecium, a multidrug-resistant bacterium commonly linked to hospital-acquired infections. 

The team administered six weeks of intravenous antibiotics, which brought the infection under temporary control, but further imaging revealed structural damage to the valve. A second operation was scheduled.

In the second surgery, the team applied a complex technique commonly used in human heart procedures but never before reported in dogs. They extended the damaged anterior leaflet of the mitral valve -- one of two flaps that open and close to regulate blood flow between the heart’s chambers -- using a bovine pericardial patch.

The patch is a sterile, medical-grade material made from the pericardium, the sac surrounding a cow’s heart, and is commonly used in both human and animal cardiac surgeries. The nine-hour operation restored the function of the valve.

The dog has since recovered and, three months post-surgery, is living normally without medication. According to the NEL team, dogs diagnosed with infective endocarditis typically survive for only about 70 days. This dog has now lived more than 10 months since its diagnosis.

“This case shows that even a condition as serious as infective endocarditis, once thought impossible to treat surgically in dogs, can potentially be overcome,” said Eom Tae-heum, lead surgeon and chief director of the NEL Animal Medical Foundation. 

He added that the milestone was the result of experience gained from more than 50 canine heart valve surgeries and that the findings will be submitted to academic journals.