LAUSR

Is there enough evidence to support the use of inferior vena cava filters?—Yes. There is a strong effort among many physicians to avoid the use of inferior vena cava filters (IVCFs) in the treatment of patients with acute deep vein thrombosis and pulmonary embolus (PE). There is no doubt that IVCF use in the United States has been skyrocketing until recently.1 There is also no debate that this increased use has been associated with observations and reports of IVCF-related complications.2 The devices have become the very public subjects of hundreds of lawsuits against manufacturers, who are likely questioning the business rationale for continuing to sell IVCFs. Admittedly, there are only sparse data regarding the survival benefit of IVCF use,3 and professional guidelines have remained consensus-based and divergent along specialty lines.4,5 This has led to sweeping condemnations and even skepticism regarding their efficacy.6 The paucity of high-level data on filters is striking in light of the length of time that these devices have been in clinical use. What little data that have been generated in randomized prospective clinical trials are fundamentally flawed in that the enrollment criteria were more liberal than even the most lenient clinical guidelines. In 2 of the most widely quoted studies evaluating the effect of IVCFs, enrolled patients had venous thromboembolic disease (VTE) that could be—and, in fact, was— treated with anticoagulant therapy.7,8 Inferior vena cava filters were explored for additive benefit to accepted pharmacologic therapy. Although the Prevention du Risque d’Embolie Pulmonaire par Interruption Cave trial demonstrated that patients with permanent IVCFs experienced fewer episodes of PE over time (evidence that IVCFs do prevent PE), there was no survival benefit.9 In the group’s second trial in 2015,10 which substituted retrievable IVCFs for permanent devices, patients with filters underwent more procedures (ie, IVCF retrieval) without added clinic benefit. To our knowledge, the populations in whom IVCF use is generally accepted as indicated (ie, patients with proximal deep vein thrombosis or PE who do not properly or adequately respond to anticoagulant therapy) or in whom IVCF use has increased (eg, patients without VTE but considered at high risk for complications if receiving pharmacologic prophylaxis, such as closed head trauma) have never been studied in a randomized prospective fashion. These populations will probably never be studied. We think (as do others) that it would be unlikely to find any physicians willing to randomize patients with acute VTE to no therapy, and the number of patients needed to appropriately power studies of prophylactic indications would be prohibitive.9 Lastly, it is important to point out that there are no data supporting the clinical benefit of IVCF retrieval. We all believe that it makes sense to remove a filter when it is no longer needed to protect patients from PE, but strong shared belief does not equal fact. So where does this leave us and our patients? We agree that indiscriminant use of IVCFs without clear indications places patients at risk of serious complications,10 and we do not support this practice. However, clinicians must remember that patients with acute proximal deep vein thrombosis and/or PE who cannot receive anticoagulation because of ongoing hemorrhage or the risk of catastrophic (eg, intracranial) bleeding and those patients with acute VTE whose appropriate anticoagulant therapy has clearly failed require effective acute protection from PE until they can adequately begin anticoagulant therapy. Inferior vena cava filters are the only acceptable alternate therapy, and there are data supporting their ability to prevent PE while demonstrating a survival benefit in these patients.4,10 Patients with murky indications should be evaluated individually, carefully, objectively, and perhaps by multiple knowledgeable physicians with differing perspectives to assess their actual risk of PE and anticoagulation-related complications. After IVCF placement, all patients must be observed carefully and systematically and evaluated for IVCF retrieval, if appropriate. As we continue to collect data on the appropriate use and complications of IVCF, we must exhibit common sense and dedication to providing the finest quality of care for our patients with VTE, including the judicious, respectful use of IVCFs. A measured approach will allow us to use IVCFs without regret, rather than regret not using or even losing access to them.