Bioconvertible IVC filters: safety, efficacy, and bioconversion times in a real-world cohort

ABSTRACT

Purpose: To examine the outcomes of patients with venous thromboembolism (VTE) who underwent placement of a bioabsorbable inferior vena cava filter (IVCF) for temporary pulmonary embolism (PE) protection Materials and Methods: From 10/1/2020 to 11/31/2021, 17 patients (mean age 71, range 45-92, 58% female) underwent placement of a bioabsorbable IVCF (Sentry, Boston Scientific) at a single academic center. Thirteen of the 17 filters (76.4%) were placed in the inpatient setting, and the remainder were placed outpatient. VTE risk factors included malignancy (70.6%), immobility (5.9%), COVID-19 (5.9%), and unprovoked (7.6%). Prior to IVCF, 11 patients presented with deep venous thrombosis (DVT) alone, two had PE alone, and four were diagnosed both DVT and PE. The contraindication to anticoagulation (AC) was active bleeding in 47.1% of the cohort, upcoming surgery in 41.2%, worsening of DVT on AC in 5.9%. and brain tumor in 5.9%. The pre-implantation infrarenal IVC diameter ranged from 1.6 to 2.6 cm. Technical success (TS), adverse events (AEs), and follow-up IVCF characteristics were recorded. Results: TS was 100%. No AEs occurred during placement. Mean follow-up period was 4.9 months (range 0-12.9). No new PEs were diagnosed after IVCF placement, and no patients required replacement of IVCF. Nine of the 17 patients had follow-up CTs after filter placement, two had follow up radiographs in which the filter state could be assessed, and the remaining six had no imaging evaluating the filter after placement. Asymptomatic IVCF associated non-occlusive thrombosis was seen in 3 patients. The longest amount of time after placement that a Sentry filter was observed to still be in the filter state was 3.9 months, and the shortest time in which imaging showed a filter bio-converted to the open state was 3.1 months. Three patients underwent serial imaging which incidentally demonstrated the timeframe in which the IVCF converted from a filter-state to an open-state. In one patient this conversion occurred between 2.1 and 3.1 months, in another between 1.7 and 3.3 months, and in the last patient between 3.9 and 4.4 months. Conclusion: In VTE patients with either a temporary contraindication to anticoagulation or a transitory high-PE-risk period, bioconvertible IVC filters are a safe and effective option for short-term protection against pulmonary embolism.