New evidence on IVC filters: low level but compelling

From a recent large database of patients with unstable PE:

Results
Among 21,095 unstable patients with pulmonary embolism who received thrombolytic therapy, in-hospital all-cause case fatality rate was lower in every age group who received a vena cava filter in addition to thrombolytic therapy (P = .0012 to less than .0001). Patients aged greater than or equal to 81 years showed the greatest absolute reduction of case fatality rate with filters (19.3%). Among 50,210 unstable patients who did not receive thrombolytic therapy, case fatality rate also was lower in every age group who received a vena cava filter (all P less than .0001). Patients aged greater than or equal to 81 years with vena cava filters showed the greatest absolute risk reduction of case fatality rate (27.7%).

Conclusion
Vena cava filters are associated with a reduced in-hospital all-cause case fatality rate in unstable adults with pulmonary embolism, irrespective of age.

This use of IVC filters is common and there is wide practice variation. It is not considered strictly evidence based, the only clearly recognized indication being a patient with acute proximal DVT and an absolute contraindication to systemic anticoagulation. The evidence quality of the findings presented above is low but at least suggests that many of the clinicians appearing to practice non-evidence based medicine (by filling in for non-evidence with clinical judgment) were right all along.