Prophylactic indications for vena cava filters: critical appraisal

Vena caval filters (VCFs) were developed and initially used for therapeutic indications, primarily to prevent recurrence of pulmonary embolism (PE) or its occurrence in selected cases of deep venous thrombosis (DVT), where risk of PE was very high and anticoagulant therapy (AC Rx) was deemed ineffective, contraindicated by concurrent disease, or had to be discontinued because of complications. Prophylactic indications-where there was no DVT or PE but the risk of them was considered very high and AC Rx was contraindicated or considered ineffective-were invoked relatively infrequently at first, but when percutaneous placement became routine in the late 1980s, this indication increased steadily. The categories of patients considered at high-enough risk of venous thromboembolism (VTE), albeit temporary, to justify VCF have also expanded steadily, most with little objective basis for choosing VCFs over other methods of prophylaxis. In many of these prophylactic categories, eg, patients undergoing surgery associated with a high risk of VTE, the risk is for a limited period only, until the patient is ambulatory or AC Rx can be instituted. In addition, there are potential disadvantages to leaving a permanent filter in, especially in younger patients with an extended longevity outlook and no ongoing risk of VTE. This was brought out in the PREPIC trial. This realization has, in turn, spurred interest in developing temporary or retrievable filters for short-term prophylactic use. No design has yet proven entirely satisfactory for this purpose, but the practice of placing such filters for prophylactic indications has steadily grown, using available devices. This article critically reviews these trends, suggests directions for future developments, and recommends necessary studies on which to base the practice of prophylactic VCF use.