Blood-clot catching devices are still in use, despite complications

Inferior vena cava selection remembers to save life. The spider-like structures trap blood before it can travel up to the lungs and cause a fatal stroke. But for more than a decade, these devices have been plagued by questions about how well they work and the serious problems they pose to patients.

New data shows they’re still at risk: Researchers examined a Food and Drug Administration database and found that adverse drug reactions to the filters increased from 1,020 in 2016 to 2,842 in 2020 – experts say the number is low and could be a sign of greater awareness among patients or an increase in the risk.

IVC filters are popular among interventional radiologists and anesthesiologists as an alternative therapy for patients who are known to have bleeding disorders that may cause medical complications, but who are unable to receive blood transfusions; for example, those who are at risk of internal bleeding and their legs are closed.


“There’s no doctor I know who doesn’t want to do the right thing for their patients,” said Sanket Dhruva, a cardiologist at the University of California San Francisco and a researcher on the report. “But a lot of times we have to deal with the intervention. We want to do something. We want to install a tool.

But it comes with significant risks that the medical community has known about for over 12 years. Some blood vessels can rupture or rupture, or blood clots can form in a deep vein. Many are removed when the risk of clotting or the inability to participate in blood transfusions has passed. But providers often don’t follow up with patients on withdrawal procedures, so consultations stay with patients for longer than necessary.


Patients, for their part, aren’t always aware of those risks until things go wrong. In recent years, some have started turning to Reddit and Facebook support groups to seek advice from removal experts, exchange information about IVC filter implants, and ask questions of their doctors.

Devices originally designed to be permanent: The first IVC filter, shaped like an umbrella and designed as a permanent implant, was developed in the 1960s and improved in the 1980s. It was the other way around when filters were used in the late 90s. A 2004 study found that the number of patients who had an IVC catheter increased from 2,000 in 1979 to 49,000 in 1999.

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With the increase in the use of filters, and the number of studies on their long-term effects, doctors realize that the devices have many problems in their price. In fact, there have been no randomized trials showing the effectiveness of the filter in preventing the disease.

“In the past, we didn’t know what was wrong,” said Osman Ahmed, an interventional radiologist at the University of Chicago. “The benefits are huge, the risks are few. Over time, we started to realize, wait, there’s a real risk here.”

Those risks were highlighted in the FDA’s 2010 safety alert urging physicians to take prescription medications when they are safe to do so, and to carefully consider the risks and benefits. benefits of withdrawal for each patient. “The FDA continues to monitor adverse events related to IVC filters, including the MAUDE database, literature, and selected observational studies of IVC filters,” a spokesperson confirmed. office to STAT.

There have also been several high-profile recalls, including two in 2005 by Boston Scientific over concerns about blood vessel rupture and embolisms. The company told STAT that it has not made or sold any IVC filter products since 2021. Cook Medical, which did not respond to STAT’s request for comment, has faced multiple legal challenges from patients reporting injury from IVC filters – and lost. In 2015, NBC discovered the issues and negotiations that CR Bard bought, now owned by medtech company BD.

“All implantable medical devices, including smaller vena cava (IVC) filters, carry life-saving risks and benefits,” a BD spokesperson said in a statement to STAT. “BD provides information on the risks and benefits of these products so that doctors can, in consultation with their patients, decide whether these benefits outweigh the potential risks at any given time.”

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The Society of Interventional Radiology released guidelines in 2020 advising doctors on how and when to implant IVC filters. Geoff Barnes, a cardiologist at the University of Michigan, helped develop this guideline. When deciding whether to implant a filter in a patient, he or she always considers blood transfusions first. If this is not an option, he will evaluate the patient’s risk of another pulmonary embolism, by carefully examining the patient for existing stones.

“If we thought that patient was at high risk, then we’d start to think about whether we should put an IVC filter in until they can be stabilized,” Barnes said.

Barnes will work with its hospital system to develop a better way to track diagnostic placement and removal. Each time an interventional radiologist or surgeon sets up a diagnosis, he or she enters the patient’s data into the registry. Hospital staff regularly review the registry so physicians know how to track patients who need their filters removed.

“We really managed this process so we weren’t relying on the patient to schedule a follow-up visit or anything,” Barnes said.

That kind of follow-up is especially important for patients like Hannah Keatts, who got an IVC filter after developing malignant tumors in her femoral artery during pregnancy and then losing 14 blood pressure at birth in September. He used to have a blood transfusion, but his doctor at Methodist Hospital in Omaha, Neb., told him he needed more treatment. “I haven’t really had a chance to get on Reddit or talk to family members or talk to other people who have an IVC filter,” Keatts said. “Boom-boom-boom is very important.”

Keatts visits her doctor every six weeks to make sure the device is working and staying in place. Within two months, it was removed and replaced with a stent to keep his blood flowing. For him, the device provides peace of mind.

“I thought about asking my doctor if he could keep it forever because I was so paranoid,” Keatts said. “You never know if another tumor will grow.”

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This is a common assumption among patients, and is one reason why negotiations remain so long. Patients who have received older, more complex filters may continue to have them for years, sometimes because their doctors have told them that the removal procedures are too risky, because the patient forgets to follow.

Ahmed has come to care for these patients, sometimes receiving 100 in one year. He found patients through the IVC Filter Facebook group and has since become an expert on filter removal. “When I read these patient stories like this, I went to my doctor and he told me I can’t take my filter,” Ahmed said. “Sometimes they post pictures and I’m like, man, I can take them down in 10 minutes.”

More recently, he has seen a drop in demand as enrollment rates drop. “We’re reaching that limit of all these old-school filters that are out there and haven’t been delivered to patients,” Ahmed said.

Filter removal is getting easier, says Kush Desai, an interventional radiologist at Northwestern. The FDA approved the marketing of a laser device from Philips that helps dissolve filters stuck in place in December 2021 (Ahmed and Desai did the research supporting the device) . The next step is to develop better IVC filters that can be inserted into the bloodstream, though Ahmed said the pandemic has halted research in that direction.

Doctors are divided on how often IVC filters should be used, especially when there is no solid blood supply. Dhruva thinks the filter’s use should be limited to patients in clinical trials until more evidence from doctors is available about its healing abilities. Desai said there are ethical concerns about denying some study participants access to IVC analysis that could mean the difference between life and death.

Those life-or-death posts, he and other experts say, drive home how important it is for doctors to follow up with patients receiving implants, and clearly presenting the risks they carry. The safety of their patients is paramount.


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