Current indications for caval interruption: should they be liberalized in view of improving technology?

Although the impressive increase in the number of filters placed since 1988 is not surprising, it is appropriate to continue to review the indications for placement to determine whether abuse of these devices is occurring. Initially, there were very stringent requirements that were appropriate because there were few data to evaluate the efficacy and safety of the device. Now, data have been accumulated indicating the Greenfield filter has a high degree of efficacy (95%) and comparable caval patency (96%)32 for 20 years.1 Knowing that the filter is safe and effective, physicians are electing to place it in patients with greater comorbidity factors or with longer life-expectancy. In addition, advances in the treatment of patients with multiple trauma and malignancy have resulted in improved survival, leaving more patients at risk of DVT and PE. Finally, the number of patients older than age 60 is increasing rapidly, and the number of elective and emergent orthopaedic procedures is growing. All of these factors have led to an increased number of filter placements that should be considered appropriate. Although there are certainly cases in which the filter was placed without sufficient justification, the explosion in use can more accurately be correlated with changes in medical care, the established efficacy and safety of the device, the growing numbers of patients diagnosed with thromboembolism, and the increased awareness of the risk of complications from anticoagulation. When filter placement is preceded by a careful assessment of the patient to determine the risks and benefits of alternative treatments, there is little danger of abuse. However, more clinical investigation will be necessary to determine the optimal, cost-effective approach in situations in which controversy currently exists.