A study published in Medscape April 2015 suggests retrievable inferior vena cava (IVC) filters fail to further improve outcomes in patients with severe acute pulmonary embolism, if those patients already receive anticoagulation therapy. The combination of a retrievable IVC filter plus anticoagulation failed to reduce the risk for symptomatic recurrent pulmonary embolism at three months, in comparison with anticoagulation alone.
IVC Filters Unnecessary
Kenneth E. Lyn-Kew, an MD from National Jewish Health in Denver, Colo., told Medscape that experts weren’t previously sure the filters were necessary. This study makes them appear unnecessary. “Now we have good evidence that the practice is not necessary,” said Lyn-Kew. (A) lot of times we have been putting these filters in despite the concern that we are putting too many of them in.”
The April 28, 2015 issue of JAMA published the study by Patrick Mismetti, MD, PhD, from Centre Hospitalier Universitaire de Sainte-Etienne, France. Mismetti and his colleagues published the results of their randomized, open-label trial of hospitalized patients. They chose to study a single filter model, used widely in France, called the ALN filter (ALN Implants Chirurgicaux),. Surgery and six-month follow-up occurred August 2006 – January 2013.
The researchers used a concealed randomization system with a central adjudication committee blinded to treatment assignments. Dr. Lyn Kew said the study was well designed and he expects the results to likely change the way he practices.
The long follow-up offered insights not readily available to the critical care physician. Dr Lyn-Kew said he especially appreciated the patient selection in the paper, which he found practical. Medscape quoted him: “They excluded the immediate post-operation patients…and got down to the bulk of the patients that we see.” The authors noted data from their control group reflected a surprisingly low rate of symptomatic recurrent pulmonary embolism.
The authors explained: “Although we sought to include patients in a high-risk category for pulmonary embolism recurrence, as reflected by our inclusion criteria, the three-month 1.5% rate (95% [confidence interval], 0.31% to 4.34%) of pulmonary embolism recurrence observed in the control group was far below the expected 8.0% rate. This rate, however, was mainly based on the results of older cohort studies in which anti-coagulation was likely to be suboptimal compared with current practice and the present study, especially in cancer patients. In recent clinical trials evaluating new oral anticoagulant agents, the rates of pulmonary embolism recurrence in patients receiving standard anticoagulation therapy were much lower (1.0% to 2.0% at up to 12 months), and close to ours.” (Medscape)
Retrievable vs. Permanent IVC Filters
Although both retrievable and permanent vena cava filters are available, retrievable vena cava filters are used increasingly to manage acute venous thromboembolism. Current data apply only to retrievable vena cava filters. According to Medscape, previously published study data suggest permanent filters, along with anticoagulation, may be effective in preventing long-term risk for recurrence of symptomatic pulmonary embolism.
Dr Mismetti reports receiving research grants from Bayer along with money for board memberships with Bayer, Bristol-Myers Squibb/Pfizer, Daiichi Sankyo; also pay for lectures from Bayer, Boehringer Ingelheim, Bristol-Myers Squibb/Pfizer, Daiichi Sankyo, sanofi-aventis; also for developing sales presentations from Bayer, Bristol-Myers Squibb/Pfizer. Dr Lyn-Kew did not disclose any relevant financial relationships.