Anticoagulation Therapy May Reduce Subsegmental Nonocclusive Inferior Vena Cava Filter–Related Thrombus Burden: A Retrospective Study in a Single-Center Institution

OBJECTIVE: To evaluate the anticoagulation therapy of subsegmental nonocclusive filter-related thrombus and identify the risk factors affecting the change in thrombus volume. METHODS: A single-center retrospective study was performed to review patients who received inferior vena cava filter (IVCF) placements and retrievals from July 2018 to December 2023. Patients with subsegmental nonocclusive filter-related thrombus were included in this study, and clinical data, such as demographics, baseline medical history, types of IVCFs, locations of IVCFs, endovascular management, duration of anticoagulation, and outcomes were collected. RESULTS: Based on IVCF location, 32 patients, including 17 men and 15 women (age: 60.94±13.47) were enrolled into infrarenal IVCF group (infra-group), 38 patients, including 28 men and 10 women (age 54.97±12.48) were enrolled into suprarenal IVCF group (supra-group). Demographics, baseline medical history, lower extremity deep vein thrombosis (DVT) characteristics, initial IVCF placement indications, IVCF types, endovascular therapy choice, and the reasons of additional anticoagulation were found no significant difference between the 2 groups (p>0.05). Additional anticoagulation time before IVCF removal in supra-group was significantly longer than infra-group (74.47±42.85 vs 51.25±25.99 p<0.05). After additional anticoagulation, most filter-related thrombus was resolved completely (34/38 vs 20/32) or partially (4/38 vs 9/32), and only 3 patients in infra-group suffered progressed filter-related thrombus. Supra-group had a significantly better outcome of filter-related thrombus than the infra-group (p<0.05). CONCLUSION: Anticoagulation therapy could reduce subsegmental nonocclusive filter-related thrombus burden. Longer anticoagulation period and suprarenal IVCF placement may be the factors influencing the thrombus resolve.Clinical ImpactThe present study found out anticoagulation therapy could reduce subsegmental nonocclusive filter-related thrombus burden, which may provide a better option for filter-related thrombus and improve the retrieval rate of inferior vena cava filters.