Filter to protect against blood clots implicated in deaths

By ThinkReliability Staff

An NBC investigation released September 3, 2015 raised concerns about the use of a specific retrievable inferior vena cava (IVC) filter, known as the Recovery. The issues behind the concerns are complex and some appear to impact more than one type of filter. A visual root cause analysis, known as a Cause Map, can clearly lay out all the causes associated with an issue, ensuring that all potential solutions can be considered.

The first step in a problem-solving process is to define the problem. Here the specific issue being investigated is the deaths and serious injuries associated with the failure of the Recovery filter. The Recovery was introduced in 2003 and was first implicated in a death in 2004. The Recovery aims to prevent blood clots from reaching the heart or lungs in patients who are unable to tolerate blood thinners and have been placed in a variety of healthcare facilities. An important difference between the expected and actual use of these filters is that studies have found that most are not removed in a timely manner.

The use of Recover filters has impacted the patient safety goal because at least 27 deaths have been related to its use. There are at least 117 lawsuits associated with these problems, impacting the compliance goal. Hundreds of additional non-fatal problems have also been reported, impacting the patient services goal. The operations goal is impacted by the filters not being removed. Lastly, the inadequate holding power of the arms of the filter (meant to hold it in place) can be considered an impact to the property goal.

The analysis begins with one of the impacted goals. Here, the primary concern is the impact to patient safety. The patient deaths result from the filter being pushed into a patient’s heart or lungs. This results from filter migration. In order for the filter to migrate, the force on the filter exceeds the holding power of the arms of the filter. Holding power can be reduced due to improper placement, filter fracture/ failure due to fatigue (a National Institutes of Health, or NIH, study found that 40% of filters fracture within 5.5 years) or design issues. Although these issues can impact any type of blood filter, the Recovery was found to have the lowest resistance to migration of filters examined. Force on the filter can be increased due to exertions, such as bowel movements or respiration, and/or large blood clots. Because these patients are known to have risk factors for blood clotting, this is a particular concern.

The time a filter is in place increases the risk of filter migration. The longer a filter is in place, the more likely it is to be impacted by the concerns discussed above. The use of these filters has been increasing. According to the US Food and Drug Administration (FDA), only 2,000 of these type of filters were installed in 1979; now about 250,000 are installed every year in the US. The devices used are approved by the FDA, though in the case of the Recovery, there are questions about the legitimacy of the review process; a “signer” on the application says her signature was forged. However, studies have found that evidence-based guidelines for implantation of these filters is not being followed, potentially leading to inappropriate use.
These filters (though designed to be temporary) are not being removed. A retrospective review of filter implantations published in the American College of Surgeons Surgery News found that only 1.6% of retrievable filters were removed during the 3-year study period. In 4.2% of cases each, filters were unable to be removed due to technical difficulties or thrombus within the filter. In most cases, though, it appears there was no attempt to remove the filter, believed to be due to a lack of physician oversight.

According to a FDA safety communication, physicians that implant a retrievable filter must remove it as soon as “feasible and clinically indicated”. This is true for all retrievable IVC filters, not just the Recovery. However, implanted Recovery filters are a particular concern – they are more prone to problems and haven’t been sold since 2005. If you believe you have an implanted filter, talk to your doctor about next steps.

To view a downloadable PDF with the causes of the filter issues, click on “Download PDF above. To learn more:

NBC Investigation

NIH Study

ACS Surgery Study

FDA Safety Communication