To the Editor Previously, we were not responding to the intended comments by Dr Hoffer.1 Herein, we address his points.
First, Dr Hoffer1 claims that inferior vena cava (IVC) filters decrease pulmonary embolism (PE), while increasing deep vein thrombosis (DVT), and that this trade-off is “arithmetic” and as it should be. This is a conceptual error. Inferior vena cava filters are supposed to capture embolized clots, decreasing symptomatic PEs, and collect thrombus on the inferior side of the filter, where intrinsic antithrombotic mechanisms should dissolve it. These captured clots should appear in neither the DVT nor PE totals and should constitute net benefit. Thus, if IVC filters are working as intended, DVTs (unembolized clots) should be unchanged, PEs should be diminished, and total venous thromboembolisms (VTEs) should be reduced. The increase in DVTs suggests the prothrombotic effect of IVC filters.