Our study found that only 30.4% of patients who underwent placement of a retrievable IVC filter and who survived to discharge had a documented plan for subsequent filter retrieval. Although most patients had justifiable reasons for filter retention, we found that 21.6% of patients without retrieval plans had no clear contraindications to filter removal. In 62 patients who underwent a filter retrieval attempt, 25.8% of attempts were unsuccessful.
IVC filters are not benign clinical interventions. Complications of filter placement include immediate issues such as problems with filter positioning, filter tilting, and technical malfunctions.21
In addition, IVC filters increase the risk for later deep venous thrombosis5,6
as well as rarer complications such as insertion site thrombosis,22
perforation of the inferior vena cava,22,23
and filter migration to the heart or lungs.24,25
These complications highlight the importance of ensuring timely removal of filters in appropriate patients.
Our study found that filter retrieval plans were less likely in patients who had a history of cancer and who were not placed on anticoagulants at discharge, a finding that most likely reflects ongoing contraindications to anticoagulation and the need for continued filter retention. However, we also found than 21.6% of patients without plans for filter retrieval had no clear contraindication to retrieval, and that these patients were more likely to be on non-medicine services and be aged 50–69 years. Knowledge of these risk factors could be helpful in developing strategies to improve the rate of appropriate filter retrieval. Although our study was unable to determine the exact reasons for retaining the filter, it is possible that ambiguity as to which service was responsible for the decision on filter removal contributed. Strategies to improve communication between services, such as by designating the service that placed the filter as responsible for follow-up and retrieval26
or by tasking nursing staff to help with follow-up plans27
, may clarify role responsibilities and improve plans for filter retrieval. In any case, developing clearer guidelines addressing which patients are appropriate candidates for retrieval and establishing standard lines of responsibility could potentially reduce the rates of inappropriate filter retention. Patients, too, may not always be informed or understand the potential harms of permanent IVC filter placement and should be educated about the importance of appropriate follow-up after filter placement.
In many situations, it may be justifiable to elect not to remove the filter. Such reasons include ongoing contraindications to anticoagulation, large emboli found within the filter or large occlusive thrombus distal to the filter, or poor patient prognosis.15
The optimal management of these patients in regard to long-term anticoagulation in the presence of an IVC filter is less clear. The proportion of patients in our study undergoing attempted filter retrieval are lower than studies of trauma patients,28–30
prospective case series to demonstrate IVC filter retrieval feasibility,13–18
and studies examining medical-surgical patients outside the US.10–12
However, our rates are comparable to those obtained at another retrospective single-center study of medical-surgical patients at an academic medical center in the US.9
Finding thrombus within the IVC filter, the most common complication precluding filter retrieval in our study, has been commonly described in other studies.3,10,16,18,23
There are several limitations to our study. Patients were identified from a single medical center, limiting generalizability. We lacked consistent long-term follow-up, which limited our ability to identify long-term complications. Our reliance on medical chart review may not have completely captured the entire decision-making process around filter placement, nor completely ascertained the contraindications to retrieval. Variation in the amount of information contained in retrospective patient records could have yielded incomplete information on indications for retention.
Despite these limitations, our study is unique in that it examines the demographic and clinical predictors of plans for IVC filter retrieval. We found that the majority of patients undergoing filter placement do not have subsequent plans for filter retrieval, although this decision is justifiable in most of the cases. However, there remains a significant proportion of patients who could be considered for filter retrieval. Efforts to improve the rates of filter retrieval in appropriate patients may help reduce the long-term complications of IVC filters.