Pathologists' puzzle: mystery of the silver-coated heart valve

(L to R) Drs. Tirone David, Jagdish Butany and Christopher Feindel strive to fine-tune the process for reviewing new devices. (Photo: The Globe and Mail)

The mechanical heart valve that Dr. Jagdish Butany holds in his hand looks surprisingly unassuming, about the size of a dime. Yet as director of cardiovascular pathology at the Peter Munk Cardiac Centre (PMCC), this particular valve took him on a mission around the world.

The mission was to solve a mystery – what was causing this manufacturer's new model of heart valve to be connected to infections in heart patients, resulting in their bodies rejecting the device and in some cases death.

The mystery started unfolding some 20 years ago, Dr. Butany explains.

"Normally, about 2 per cent of prosthetic heart valves that are implanted do get infected," he says. "You make something by hand or with machinery, and somewhere along the line, if the sterilization is not adequate, you can get bugs coming in."

In the late 1990s, one of the manufacturers brought out a new model. It was offered to leading heart institutes at no extra cost because it included only a small improvement – a coating of silver along its edge that was intended to prevent infection.

Trouble is, more patients than usual actually had infections after receiving this device. Instead of the normal percentage of patients whose valves had to be replaced, within months the numbers kept going up.

"When we had eight [infections], I said, 'This is too much.' Unfortunately, prosthetic heart valves behave differently in different people," Dr. Butany says.

While Dr. Butany knew the problem needed attention, he didn't think dealing with this valve would become the cornerstone of his life's work.

• Read more about the mystery of the silver-coated heart valve

 

The third annual Peter Munk Cardiac Centre (PMCC) magazine published by The Globe and Mail focuses on why Canada's premier cardiac centre is known for being "the heartbeat of innovation." The magazine explores the PMCC model that supports the creation, development and evolution of innovative ideas into action – making "today's idea, tomorrow's practice." It also examines the impact that a culture of innovation has on the way cardiovascular care is delivered now and into the future.