Analysis of Inferior Vena Cava Filter Indications and Retrieval Rates at an Academic Medical Center in Appalachia

Introduction: Inferior vena cava (IVC) filters are placed for prevention of pulmonary embolism in patients with venous thromboembolism (VTE) and a contraindication to anticoagulation. Additional clinical indications for IVC filters, such as pre-operative prophylaxis for VTE and extensive VTE, are controversial and vary across clinical guidelines. Current guidelines recommend that IVC filters be retrieved after resolution of their clinical indication. A common problem is failure to retrieve IVC filters when indicated, resulting in prolonged or indefinite placement of these devices. Failure to remove IVC filters contributes to an increased risk of filter-associated complications such as device migration, embolization to the cardiopulmonary circulation, perforation and increased risk of deep vein thrombosis (DVT). The goal of this study is to identify IVC filter indications and retrieval statistics at our academic medical center in Appalachia. We seek to compare our performance to national averages, identify the reasons for failure of retrieval in our patient population and develop quality improvement initiatives to improve our performance.

Methods: An IRB-approved, single-institution, retrospective chart review was conducted for all patients who had an IVC filter placed between January 2020 and December 2022 at West Virginia University Hospital. Patient demographics, comorbidities, placement indications, retrieval statistics and filter-associated complications were obtained from the electronic medical record (EMR). Patients who had a permanent IVC filter placed were excluded from the final analysis. Statistical analysis was performed using Mann-Whitney U and Chi squared tests where appropriate to compare the retrieval and failure of retrieval groups.

Results: The study sample (n=450) had a mean age of 65.3±15.4 years and was comprised of 54.2% males and 45.8% females. West Virginia residents comprised 82.4% of the study sample. The most common reported clinical indications for placement included VTE with a contraindication to anticoagulation (62.4%), preoperative prophylaxis for VTE (15.8%), extensive VTE (15.3%), pharmacomechanical thrombectomy (15.0%) or other (3.1%). The rate of IVC filter retrieval was 25.4% (n=114). The most common reasons for failure of retrieval were loss to follow-up (31.8%), other reasons including provider or patient preference (31.5%), patient death (28.3%), clinical indication remains present (5.7%) and unsuccessful retrieval (2.7%). Patients in the failure of retrieval group (n=114) were significantly older (69 vs 61 years, p<0.001) and had a higher frequency of clinical indications for history of VTE with a contraindication to anticoagulation (231 vs 50 patients, p<0.0001) and extensive VTE (49 vs 20 patients, p<0.0001) compared to retrieval group (n=336). There was a nonsignificant trend toward greater frequency of chronic conditions in the failure of retrieval group including cancer history (101 vs 26 patients, p=0.15), heart failure (44 vs 11, p=0.41) and hypercoagulable disease (16 vs 2 patients, p=0.26).

Conclusions: Our institution had a lower IVC filter retrieval rate than the estimated average of 34% reported in a systematic review by Angel et al. Patients with comorbid conditions tended to not undergo retrieval, predisposing them to a higher risk of filter-associated complications. A history of VTE with a contraindication to anticoagulation was the most common clinical indication for placement, but the other most common indications are not universally guideline recommended which identified an area of opportunity for multidisciplinary provider education. Patient loss to follow-up is the predominant reason for failure of retrieval at our institution, which is consistent with the healthcare disparity faced by our predominantly rural, Appalachian patient population of travelling long distances to our tertiary center to obtain specialty care. Quality improvement strategies to mitigate this limitation in the context of IVC filter placement through close local follow-up for timely reassessment, retrieval evaluation and removal will be developed.