Water filters, oil filters on a motor vehicle, furnace filters, dust filters – all must be removed and replaced at some point in order for the machinery to continue to function properly. Logically, this should apply to IVC filters as well. However, removal of the IVC filter from a patient has proven to be extremely problematic. Once implanted, they have a tendency to fall out of place, migrate to other parts of the body and break apart. The shards can cause severe injury to arteries and organs.
The manufacturer of this device advertised it as removable. However, this has not been the case. Even though the FDA has only recently issued a warning on this matter, it has been noted by the medical community as early as 2010, when an article in the February issue of Endovascular Today published an article on studies demonstrating the difficulty of removal as well as the low success rate. Furthermore, the longer the IVC filter remains in place, the more difficult removal becomes.
Recently, physicians and surgeons at Rush University Medical Center have been exploring new methods to remove IVC filters that could not be removed from patients before. Last month, Dr. Osman Ahmed, an interventional radiologist, published an article in the Journal of Vascular and Interventional Radiology in which he states, “We have both the standard retrieval methods as well as the most advanced tools to remove any type of filter, and we have the medical expertise to treat any complications from the filter being implanted.”
The new methods involve “snaring” the filter, preventing it from moving – then trapping it with a cover that prevents fragments from escaping into the blood stream in case the device shatters. Because of the work at Rush University, the success rate for retrieval has gone from an average of 22% to 100% since 2011. The procedure, which is usually done under conscious sedation (except for more difficult cases, which are performed under general anesthesia) is done through a small incision (no more than 5 millimeters) into a neck or groin artery. A wire, catheter or other device is then inserted in order to retrieve the filter.
The IVC (for “Inferior Vena Cava”) filter first won FDA approval in 2003. They were approved for patients at risk for deep vein thrombosis (DVT) in 2012 in order to prevent blood clots from reaching the heart or lungs. The idea was to remove them once the danger of a blood clot had passed – but in many cases, the device was left inside the patient. Today, the FDA is recommending that patients with an IVC consult with an interventional radiologist in order to determine if the device can be removed safely.