Health Canada and the U.S. Food and Drug Administration are near opposites in their responses to rising evidence of patient harms caused by some medical devices.
A new B.C. study has added to the mounting evidence about potential complications from the plastic-like coatings on devices such as catheters, guide wires and stents that are inserted through blood vessels during minimally invasive medical procedures.
Such devices are coated so they can slide through vessels with less friction and less damage to tissues. But the Vancouver study of 110 patients who died within 90 days of having procedures with coated devices showed that 23 per cent had polymer fragments scattered in different parts of their bodies. Three deaths were judged to be definitively caused by the dislodged material.
Hydrophilic polymer embolism is the term used by experts to describe the recently recognized phenomenon in which the foreign material separates from device surface and travels through the bloodstream to various organs in the body.
The FDA issued a safety bulletin in 2015 which said there were 500 reports of coating delamination in just two years. There were also 11 device recalls and nine U.S. deaths associated with the peeling or flaking from guide wires used during cardiac angiograms or angioplasties. Last year, the FDA followed up with additional recommendations.
Health Canada, by contrast, has taken a monitoring position.
Eric Morrissette, the department’s chief media relations officer, said in an email: “The department reviews data associated with the delamination of coatings to ensure that such devices do not shed material. In addition, the labelling of these devices sold in Canada must contain warnings to inspect the devices for any signs of damage (kinked or weakened segments, or delamination of coatings).
“Health Canada’s position is that the benefits of these products continue to outweigh the risks. This balancing of benefits and risks is a key part of any assessment for a medical device or drug in Canada.”
The Canadian agency is aware of the FDA notices, Morrissette said, but has not issued its own.
“Should new evidence come to light related to the safety of these devices, Health Canada will take appropriate action,” he said.
Devices inserted through blood vessels for so-called endovascular procedures in B.C. include those made by companies like Bard, Cook, Boston Scientific, Gore and Canadian Hospital Specialties. Some manufacturers were repeatedly contacted by Postmedia for responses to the latest study. All declined to comment.
Dr. Dave Wood, a Vancouver interventional cardiologist and director of the Vancouver General Hospital cardiac catheterization laboratory, said the study “absolutely” poses some “intriguing hypotheses” that need further investigation.
“To be truthful, it wasn’t on my radar. But it is now. And I’m not trying to belittle the study, but we have clinical trial data on these devices showing they are generally safe and effective.”
Wood said he’s not aware of any occasion when coatings has come off devices he’s used. Patients undergoing endovascular procedures are cautioned about the small risk of heart attacks and strokes after such procedures. The fact that coating debris has been found to have caused three deaths is not going to change the general information he gives patients during the informed consent process although he acknowledged patients may now ask about it because of news coverage.
He said he’s anxious to collaborate on further research and has already reached out to the study leader Dr. John Maguire, a neuropathologist.
In 2017, Dr. Rashi Mehta and Dr. Rupal Mehta, U.S. experts, gave an update for physicians about the significant complications that can ensue from device delamination.
This week, Rupal Mehta said there has been enormous pushback from physicians and medical device industry personnel who insist complications are too rare to worry about.
Dr. Harry Vinters, a professor and anatomical pathologist at Ronald Reagan UCLA Medical Center who has collaborated on research into the coating problem, praised the Vancouver researchers.
“Their study is especially intriguing in that it utilizes what could be considered old technology — careful tissue analysis of autopsy specimens — to derive extremely important new information that has a direct impact on outcomes in a select group of patients. Indeed, the autopsy is about the only way this data could have been derived, and Dr. Maguire and his colleagues are to be congratulated for the care with which the study was performed and the data analyzed.”
Vinters said despite the latest research, it is still impossible to quantify the degree of risk.
“Autopsy studies are not population-based studies, they look at highly selected individuals.”
Asked if interventional cardiologists and other specialists using such devices should give patients specific information about such risks during the informed consent process, he said:
“Generally, consents given by both anesthesiologists and surgeons are all-encompassing and include warnings about possible negative outcomes.”
Christopher Thrall, spokesman for the Canadian Patient Safety Institute, said studies like the one in Vancouver are important and while the agency doesn’t have any statistics on delaminations on device coatings, Canadian patients are generally vulnerable to adverse events in the hospital because of such things as faulty devices, medications, mistakes and falls. For instance:
• Every 17 minutes someone dies in a Canadian hospital from complication of treatment. That’s about 31,000 people a year.
• There are hundreds of thousands of preventable patient safety incidents each year. One out of 18 hospital visits results in preventable harm.
• Over 40 per cent of complex surgical patients suffer harm. Patients who suffer harm are four times more likely to die in hospital than those who don’t.
Thrall said the Institute for Safe Medication Practices Canada, Health Standards Organization, and the Canadian Patient Safety Institute are working together to support a Health Canada initiative that requires health care institutions to identify and report on serious adverse drug reactions and medical device incidents.