July 08, 2019
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Vena cava filters after major trauma fail to reduce incidence of pulmonary embolism, death

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Placing an inferior vena cava filter in patients within 72 hours of major trauma did not reduce incidence of symptomatic pulmonary embolism or death at 90 days, according to results of a randomized prospective trial published in The New England Journal of Medicine.

“The use of vena cava filters has become widespread in many trauma centers as a primary means to prevent pulmonary embolism in patients who are at high risk for bleeding,” Kwok M. Ho, PhD, intensive care specialist and clinical epidemiologist at Royal Perth Hospital in Australia, and colleagues wrote. “Given the cost and risks associated with a vena cava filter, our data suggest that there is no urgency to insert the filter in patients who can be treated with prophylactic anticoagulation within 7 days after injury.”

Ho and colleagues randomly assigned 240 patients with severe injuries (median injury severity score, 27; range, 0-75) and a contraindication to blood thinners to receive a vena cava filter within 72 hours of injury (n = 122; median age, 35 years; range, 25-56; 77% men) or no filter (n = 118; median age, 41 years; range, 29-58; 76.3% men).

Among the 122 patients in the filter cohort, 89% had the filter installed within 24 hours of enrollment.

A composite of symptomatic PE or death from any cause at 90 days served as the study’s primary endpoint. Symptomatic PE between days 8 and 90 in a subgroup of patients (n = 80) who survived at least 7 days without prophylactic anticoagulation served as a secondary endpoint.

Results — published in NEJM to coincide with the International Society on Thrombosis and Haemostasis 2019 Congress in Melbourne — showed no significant difference in incidence of PE or death among patients who received a vena cava filter compared with those who did not (13.9% vs. 14.4%; HR = 0.99; 95% CI, 0.51-1.94).

However, among the subgroup of patients who did not receive prophylactic anticoagulation within 7 days of injury, five patients — none of whom received a vena cava filter — developed PE, including one who died (RR for PE = 0; 95% CI, 0-0.55).

An entrapped thrombus was discovered in the filter of six patients who received the device.

Researchers noted that the study was underpowered to identify modestly lower occurrence of PE or death in the filter vs. no-filter group, which served as a limitation. They also cited several caveats to the study’s secondary endpoint, including survivor bias because a patient had to survive 7 days to qualify for the subgroup analysis.

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“Previous studies have suggested that vena cava filters are associated with an increased risk for deep-vein thrombosis in the legs,” Ho and colleagues wrote. “This complication was not confirmed in this trial — perhaps because of the use of intermittent pneumatic compression in the legs, the initiation of prophylactic anticoagulation, and the removal of the filter as early as possible.” – by John DeRosier

Disclosures: Ho reports advisory roles with Medtronic and research funding from Raine Medical Research Foundation and Royal Perth Hospital. Please see the study for all other authors’ relevant financial disclosures.