This is despite mounting evidence supporting restricted use as recommended in guidelines. This was the topic of several articles of interest in the May issue of Thrombosis Research.
Methods and results
We analyzed hospital discharge records of all patients with active cancer who were admitted to a California hospital specifically for acute DVT or PE between 2005 through 2009. Propensity and competing risk methodology were used to determine if IVCF-use lowered either 30-day mortality or the risk of recurrent PE, DVT, and major bleeding within 180 days. Among 14,000 patients, an IVCF was placed in 2747 (19.6%), but only 577 (21%) of these IVCF patients had an apparent indication for filter use because of acute bleeding or undergoing major surgery. Data on anticoagulation use was not available. Filter-use provided no reduction in either 30-day mortality (HR = 1.12, 95% CI: 0.99–1.26, p = 0.08) or the adjusted 180-day risk of subsequent PE (±DVT) (HR = 0.81, 95% CI: 0.52–1.27, p = 0.36). Filter use was, however, associated with an increase in the adjusted180-day risk of recurrent DVT (HR = 2.10, 95% CI: 1.53–2.89, p less than 0.0001).
We conclude that in this population-based study, approximately 20% of cancer patients with acute VTE received an IVCF, but only 21% of these had an indication for IVCF use. Overall, IVCF use provided neither a short-term survival benefit nor a reduction in risk of recurrent PE, but IVCF use was associated with a higher risk of recurrent DVT.
Inferior vena cava filters are used to prevent embolization of a lower extremity deep vein thrombosis when the risk of pulmonary embolism is thought to be high. However, evidence is lacking for their benefit and guidelines differ on the recommended indications for filter insertion. The study aim was to determine the reasons for inferior vena cava filter placement and subsequent complication rate.
Materials and methods
A retrospective cohort of patients receiving inferior vena cava filters in Edmonton, Alberta, Canada from 2007 to 2011. Main outcome was the indication of inferior vena cava filter insertion. Other measures include baseline demographic and medical history of patients, clinical outcomes and filter retrieval rates.
464 patients received inferior vena cava filters. An acute deep vein thrombosis with a contraindication to anticoagulation was the indication for 206 (44.4%) filter insertions. No contraindication to anticoagulation could be identified in 20.7% of filter placements. 30.6% were placed in those with active cancer, in which mortality was significantly higher. Only 38.9% of retrievable filters were successfully retrieved.
Inferior vena cava filters were placed frequently in patients with weak or no guideline-supported indications for filter placement and in up to 20% of patients with no contraindication to anticoagulation. The high rates of cancer and the high mortality rate of the cohort raise the possibility that some filters are placed inappropriately in end of life settings.