Vena Cava Filters Do Not Add to Anticoagulant Therapy

Lara C. Pullen, PhD

April 29, 2015

A new study suggests that retrievable inferior vena cava filters do not further improve outcomes in patients with severe acute pulmonary embolism who receive anticoagulation therapy. Specifically, the combination of retrievable vena cava filter plus anticoagulation did not reduce the risk for symptomatic recurrent pulmonary embolism at 3 months compared with anticoagulation alone.

"Now we have good evidence that the practice is not necessary. Before we weren't sure," Kenneth E. Lyn-Kew, MD, from National Jewish Health in Denver, Colorado, told Medscape Medical News. "A lot of times we have been putting these filters in despite the concern that we are putting too many of them in," he added. Dr Lyn-Kew was not affiliated with the study.

Patrick Mismetti, MD, PhD, from Centre Hospitalier Universitaire de Sainte-Etienne, France, and colleagues published the results of their randomized, open-label trial of hospitalized patients in the April 28 issue of JAMA. They chose to study a single filter model called the ALN filter (ALN Implants Chirurgicaux) because of its widespread use in France. Surgery and 6-month follow-up occurred between August 2006 and January 2013.

The researchers used a concealed randomization system and had a central adjudication committee that was blind to treatment assignments. Dr Lyn Kew said the study was well designed and the results will likely change the way he practices medicine.

The long follow-up provided insights that are not necessarily available to the critical care physician. Dr Lyn-Kew especially appreciated the patient selection in the paper: "They excluded the immediate postoperation patients...and got down to the bulk of the patients that we see," he explained. The authors note, however, that data from their control group reflect a surprisingly low rate of symptomatic recurrent pulmonary embolism.

"Although we sought to include patients in a high-risk category for pulmonary embolism recurrence, as reflected by our inclusion criteria, the 3-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," the authors explain. "This rate, however, was mainly based on the results of older cohort studies in which anticoagulation 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."

Although both retrievable and permanent vena cava filters are available, retrievable vena cava filters are increasingly used to manage acute venous thromboembolism. The current data apply only to retrievable vena cava filters. Data from a previously published study suggest that permanent filter deployment plus anticoagulation may be effective in preventing long-term risk for recurrence of symptomatic pulmonary embolism.

Dr Mismetti reports receiving research grants from Bayer and fees for board memberships from Bayer, Bristol-Myers Squibb/Pfizer, and Daiichi Sankyo; for lectures from Bayer, Boehringer Ingelheim, Bristol-Myers Squibb/Pfizer, Daiichi Sankyo, and sanofi-aventis; and for development of educational presentations from Bayer, and Bristol-Myers Squibb/Pfizer. Filters were packaged and provided free of charge by ALN Implants Chirurgicaux. Dr Lyn-Kew have disclosed no relevant financial relationships.

JAMA. 2015;313:1627-1635. Abstract

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