Filters offer no added benefit for recurrent pulmonary embolism

Anticoagulation won and retrievable inferior vena cava filters lost in a randomized clinical trial that assessed their benefit and risk in patients at a high risk of recurrence of pulmonary embolism. Improvements in the former may have leveled the playing field.

Patrick Mismetti, MD, PhD, of Hôpital Nord in Saint-Etienne, France, and the PREPIC2 (Prevention of Recurrent Pulmonary Embolism by Vena Cava Interruption 2) study group published their results in the April 28 issue of JAMA. The study was designed to assess the efficacy and safety of retrievable inferior vena cava filters plus anticoagulation compared with anticoagulation alone for preventing recurrence of pulmonary embolism in high-risk patients.

They randomized 399 patients who had been hospitalized between 2006 and 2012 at 17 centers in France for acute pulmonary embolism associated with deep-vein or superficial-vein thrombosis. Vascular and interventional radiologists inserted a retrievable vena cava filter (ALN filter, ALN Implants Chirurgicaux) within 72 hours in the filter group patients, which was removed after three months. Both groups received full-dose anticoagulation treatment for at least six months.  

At three months, the rate of recurrence in the filter group was 3 percent vs. 1.5 percent for the anticoagulation alone group. Each group had one more pulmonary embolism recurrence by six months. They found no differences between the two approaches for deep vein thrombosis, major bleeding or death at three and six months.

Their findings didn’t support the use of retrievable vena cava filters in this patient population, they wrote. They pointed out that their expected event rate in the anticoagulation alone group was 8 percent, based on previous studies. The 1.5 percent rate of recurrence in their control group might reflect improvements in anticoagulation between then and now.

“We believe that the low rate of events observed in the control group of our study is consistent with contemporary care, indicating that modern management with full-dose anticoagulation therapy is likely very effective even in patients usually considered to be at high risk for recurrence, rendering unnecessary additional therapy such as inferior vena cava filters,” they proposed.

For ethical reasons, PREPIC2 did not include patients who were contraindicated for anticoagulation or in whom anticoagulation was not effective. In those patients, “filter placement represents practically the sole therapeutic option,” they wrote.