Inferior vena cava (IVC) filters are the devices that are used for conditions like pulmonary embolism (PE) or deep vein thrombosis. The IVC filters are used to prevent blood clots from travelling to lungs from deep vein in the legs. IVC filters are generally inserted in the main vessel that returns blood from lower half of the body to prevent blood clot from leg travelling into lungs, which can be fatal.
The U.S. Food and Drug Administration (FDA) warned that certain IVC filters can fracture and migrate to other parts of the body. FDA has received 921 adverse events reports since 2005 related to the IVC filters, which were manufactured by ten companies including Angiotech Pharmaceuticals, (ANPI), a unit of J&J and a unit of C.R. Bard Inc (BCR). The FDA said the use of IVC has grown in the past several years. In 2007 about 167,000 filters were implanted with projections of 259,000 implantations by 2012.
The report includes device migration or moving in the body, detachment of device parts; filter fracture and perforation of the inferior vena cava. There are two types of IVC filters, permanent and retrievable for the patients who can’t take or respond to anti-clotting medications. . Retrievable filters are meant for temporary use and FDA found more events related to the retrievable filter. “The FDA is concerned that these retrievable IVC filters, intended for short-term placement, are not always removed once a patient’s risk for PE subsides,” the agency said in a statement posted to its website Monday.
FDA does not have detailed list of reports sorted by manufacturer. A report was published in Archives of Internal Medicine regarding problems associated with two types of filters made by C.R. Bard. One filter, the Bard Recovery filter, was available from April 2003 through October 2005. It was then modified to reduce the risk of fracture and is sold as the Bard G2 filter. The report includes:
- 80 patients who received device between April 2004 and January 2009.
- Fluoroscopy was used to...
look at condition of the filter and if the filter was found, additional testing was done.
- Out of 28 patients who received the older Bard Recovery filter, seven experienced a filter fracture for a fracture rate of 25%.
- Among the 52 patients who received the Bard G2 filter, six patients had a fracture for a rate of 12%.
The data for new device is skewed from the fact that the average time of implantation and fracture assessment was about 50 months for patients with the older device compared to about 24 months for patients with the newer Bard filter.
Regarding the six fractures seen in the new device, following observation were made:
- four stayed local to the device implant
- one fragment migrated to the lung and
- in another case a device fragment traveled to the hepatic vein, which drains blood from the liver.
Whereas in seven fractures seen in the older Bard device, device fragments traveled to the heart in most cases. At least one of the patients had emergency surgery to remove the device fragment, researchers reported.
The reports from the FDA revealed the issues with the IVC filters and the harm caused to patients due to its fracture. I hope to see a more comprehensive data from FDA categorized based on the company and the individual devices. Although, retrievable filters are to be removed after some time, tissue growth over the device can pose problem of its removal. None-the-less, FDA should take a stringent action to ensure patient safety.