B.C. study uncovers deaths caused by medical device coatings

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B.C. study uncovers deaths caused by medical device coatings

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B.C. study uncovers deaths caused by medical device coatings coming loose

Fragments of medical device coating materials can break off and cause major complications, even death

Vancouver Sun - March 25, 2019

The deaths of at least three people who had hospital procedures in Vancouver were caused by coatings that sloughed off medical devices like catheters and scattered through blood vessels to major organs, a major study has found.

Eight local researchers studied autopsy reports of hundreds of people who died at Vancouver General Hospital and St. Paul’s Hospital from 2010 to 2016. They identified 110 who had died within 90 days of endovascular procedures, done by threading devices like catheters and stents through blood vessels. The devices are coated with lubricating, plastic-like materials to improve their maneuverability and to reduce friction and damage to blood vessels.

The B.C. study — published in the journal Cardiovascular Pathology and the first of its kind in Canada — found that it was not uncommon for the coating material to come off and travel through the blood to areas where the fragments can cause inflammation or block blood flow to critical organs. In the worst cases, the material can cause major tissue damage leading to fatal strokes or heart attacks.

The study may underestimate the proportion of patients hurt by the coatings since it only looked at patients on whom autopsies were conducted and such post mortems are becoming more infrequent. As well, some patients might have died after the 90-day period. The researchers conclude that any individual undergoing an endovascular procedure with a coated device is at some risk of complication from the foreign material.

Endovascular procedures are less invasive and traumatic than, for example, open heart surgery. A common endovascular procedure to look at whether heart vessels are blocked is angiography (also known as an angiogram). Another is angioplasty, done to prop open narrowed arteries with stents to improve blood flow.

Several other studies in recent years — by American physicians such as Dr. Rupal Mehta, a neuropathologist at the University of Rochester, and Dr. Rashi Mehta, a neuroradiologist at West Virginia University — found the coatings can delaminate, pointing to the need for improvements in manufacturing, product testing, surveillance, and regulations.

The U.S. Food and Drug Administration issued a warning in 2015 about coating separation and, since then, there have been numerous recalls and label warnings. Health Canada is merely monitoring the situation.

“Peeling, flaking, shedding, delaminating or sloughing off of these coatings may cause serious injuries to patients,” the FDA warning said. It attributed the problem to factors including the anatomy of patients, doctors being too aggressive in pushing catheters through certain areas, improper handling and storage of the devices, and design and manufacturing issues.

Health Canada has not followed suit.

In the Vancouver study, researchers reviewed MRI and CT scan images of patients before and after procedures and 3,500 slides of preserved tissue samples from various organs. Researchers detected coating fragments in organs like the kidneys, lungs, and heart in 25 of the 110 cases, or 23 per cent. But the breakdown of the catheter coating was deemed to be the definite culprit causing death in only three cases. Foreign material, calcified plaque, air and other particles blocking blood and oxygen supply were factors in 22 of the other deaths.

Dr. John Maguire, a neuropathologist at VGH and co-author of the study, said he became aware of the potential complications a few years ago, so in 2016, he gave information sessions to neurologists and interventional cardiologists. He then gathered a team to start the study.

“My job as a neuropathologist is to diagnose diseases of the brain and central nervous system. When I was examining a brain during an autopsy of an individual who had a cardiovascular procedure there was some material seen that I didn’t recognize. It looked foreign, it was a light blue colour. A colleague working on other tissue identified something similar in the heart and asked if I had seen anything similar in the brain. That laid the foundation for this research,” he said.

Maguire said he is unable to name any particular manufacturers or devices which are particularly risky because none seemed worse than others. Also, it’s not unusual for patients to have more than one procedure close together, so it was impossible to implicate the coating as coming from specific procedures and devices. And, many of the patients who died were quite ill with heart disease, diabetes, or other conditions before their procedures. The average age of subjects in the study was 65.

“The benefits of these devices still highly outweigh the risks. The devices were developed to facilitate procedures that would otherwise require far more aggressive treatment,” he said.

“Plastics are ubiquitous in medicine and all around us. So it is clear we need to be more vigilant in monitoring and reporting the complications, not to mention making improvements in the design of devices.”

PART TWO: FDA and Health Canada take different approaches to the problem

FDA issues device warning; Health Canada in monitoring mode

Hydrophilic polymer embolism the medical name for coating material that separates from medical device surfaces and causes complications.

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 have 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.

https://vancouversun.com/news/national/ ... -0wMiJ9AR0

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PTFE medtech coatings problems:
https://www.mddionline.com/how-prevent- ... gs-flaking
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