Multicenter Trial of Vena Cava Filters in Severely Injured Patients - Vena Cava Filters in Severely Injured Patients
Contribution To Literature:
The trial showed that prophylactic implantation of an IVC filter among young patients presenting with major trauma who have a contraindication to anticoagulants does not result in a greater reduction in PE or death at 90 days, compared with standard management without IVC filter placement.
The goal of the trial was to compare the safety and efficacy of prophylactic placement of a retrievable inferior vena cava (IVC) filter for prevention of pulmonary embolism (PE) in patients presenting after major trauma.
Within 72 hours of presentation, eligible patients were randomized in a 1:1 fashion to either vena cava filter placement (n = 122) or no filter/control (n = 118). The type of filter used was at the discretion of the interventional radiologist performing the procedure, but they had to be retrievable. All filters were removed as soon as prophylactic anticoagulation was safely established or before 90 days, unless there was a strong indication to leave the filter longer than this prespecified period.
- Total number screened: 1,714
- Total number of enrollees: 240
- Duration of follow-up: 90 days
- Mean patient age: 38 years
- Percentage female: 23%
- Age ≥18 years
- Trauma with Injury Severity Score >15
- Contraindication to receipt of prophylactic anticoagulation within 72 hours of admission
- Imminent death
- Confirmed PE on admission
- Systemic anticoagulant before injury
- Unavailability of interventional radiologist to place IVC filter within 72 hours
Other salient features/characteristics:
- Median time from injury to enrollment: 33.5 hours
- Median Injury Severity Score: 27
- Median initial Glasgow Coma Scale score: 10
- IVC filter nonremoval at 90 days: 34.3%
The primary efficacy outcome, symptomatic PE or death at 90 days for IVC filter vs. control, was 13.9% vs. 14.4% (p = 0.98). All-cause mortality was 13.1% vs. 9.3% (p > 0.05).
Secondary outcomes for IVC filter vs. control:
- Major bleeding at 90 days: 70.5% vs. 66.1% (p > 0.05)
- Nonmajor bleeding at 90 days: 23.8% vs. 17.8% (p > 0.05)
- Symptomatic PE between days 8-90 among patients who did not receive anticoagulation within 7 days of injury: 0% vs. 14.7% (p < 0.05)
The results of this trial indicate that prophylactic implantation of an IVC filter among young patients presenting with major trauma who have a contraindication to anticoagulants does not result in a greater reduction in PE or death at 90 days, compared with standard management without IVC filter placement. These are important results, since IVC filters are frequently implanted in this setting. There were also some important safety concerns – there were several instances of adherent/tilted filters at the time of removal, and a repeat attempt was necessary in 6%. Also, nearly a third did not have their filter taken out, mostly due to loss to follow-up. In the real world, this proportion is likely to be even higher, with the attendant risk of migration, perforation, adhesion formation, and other complications. These filters are also expensive, and a strategy of routine implantation is likely to be wasteful based on these findings.
In a subgroup analysis, in patients who could not receive anticoagulation within 7 days such as those with intracranial contusions or hematomas, there was a significant reduction in symptomatic PEs with IVC filter placement. This observation could be a reflection of survival bias, but is hypothesis-generating and deserves further study.
Ho KM, Rao S, Honeybul S, et al. A Multicenter Trial of Vena Cava Filters in Severely Injured Patients. N Engl J Med 2019;381:328-37.
Keywords: Anticoagulants, Cardiology Interventions, Contusions, Hematoma, Hemorrhage, Pulmonary Embolism, Radiology, Interventional, Secondary Prevention, Vascular Diseases, Vena Cava Filters, Vena Cava, Inferior, Venous Thromboembolism
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