Dear Doctor Letter for IVC Filter Use
On July 25, 2016, Health Canada sent a “Dear Healthcare Professional Letter” (a ‘Dear Doctor letter’ in American parlance) to warn doctors and other medical professionals about the dangers of IVC filters. The IVC Filters named in the letter include those made by Bard, Cook Medical, B. Braun and Cordis.
The letter said its intended audience was physicians who request or implant Inferior Vena Cava (IVC) filters and clinicians responsible for follow-up care: radiologists, cardiologists, vascular surgeons, thrombosis specialists, internists, emergency physicians, bariatric surgeons, orthopaedic surgeons, primary care physicians.
It also asked these professionals to distribute the letter to “relevant departments and appropriate personnel who use IVC filters.”
Limited Indications for IVC Filters
Healthcare professionals were cautioned in the letter that they should carefully consider the indications for IVC filters. Health Canada said the IVC filter should be considered only for patients with acute proximal deep vein thrombosis (DVT) of the leg, and those with acute pulmonary embolism (PE) IF those patients also have a contraindication to anticoagulation (blood thinner medication such as cumadin).
Retrievable IVC Filters short-term only
The letter further cautioned that retrievable IVC filters are intended only for short-term placement. When possible, they should be removed when anticoagulation therapy can be started or if a patient’s PE risk subsides.
Health Canada encourages each hospital to identify all patients who have a retrievable IVC filter placed and to develop a formal strategy to assess these patients for filter removal.
Health Canada said it had received 121 reports of serious complications associated with IVC filters as of June 6, 2016. Serious complications such as caval perforation, caval thrombosis, filter fracture and fragment embolization, intracardiac migration, cardiac perforation, cardiac tamponade, and death have been reported in patients who have been implanted with IVC filters. Many of these complications occurred with long-term (greater than 30 days) filter implantation. These complications have also been reported internationally.
Health Canada named six IVC filter makers and twelve (12) different IVC blood clot filter products in the letter:
Filter & Maker:
• ALN Vena Cava Filter (Retrievable)
• Denali Vena Cava Filter (Retrievable)
• G2 Filter System (Retrievable)
• Simon Nitinol Vena Cava Filter (Permanent)
B. Braun Medical:
• VenaTech LP Vena Cava Filter (Permanent)
• Optease Vena Cava Filter (Retrievable)
• Trapease Permanent Vena Cava Filter
William Cook, Europe APS And Cook, Inc.:
• Cook Celect Platinum Vena Cava Filter (Retrievable)
• Cook Celect Vena Cava Filter (Retrievable)
• Gianturco-Roehm Birds Nest Vena Cava Filter (Permanent)
• Gunther Tulip Vena Cava MREye Filter Set (Retrievable)
REX Medical, LP
• Option Retrievable Vena Cava Filter System (Retrievable)
Randomized Control Trials show IVC Filters fail efficacy
Randomized control trials are the gold standard for testing medical device safety. Health Canada said there have been several clinical studies of IVC filters, but only two randomized controlled trials (RCTs). Results from those two RCTs fail to support IVC filter use in patients who can be treated with anticoagulation. In addition, those RCTs failed to show reductions in VTE and mortality.
IVC Filters Risk Serious Complications
Health Canada also noted that it is working with IVC filter makers to monitor post-market safety and effectiveness of IVC filters in Canada and worldwide. Health Canada has required IVC filter makers to put post-market evaluations in place that could include Canadian registries. The agency said it wants to “further understand appropriate patient populations that should be treated with IVC filters.” Health Canada said it is also sharing this important IVC filter safety information with healthcare professionals via fax, in addition to publication on Healthy Canadians Web site, as well as MedEffect.