Inferior vena cava filters (IVCFs): a review of uses and application to international guidelines at a single Australian center; implications of venous thromboembolism associated with malignancy

Comparison of inferior vena cava filter use and outcomes between cancer and non-cancer patients in a tertiary hospital

BACKGROUND

While accepted indications for the use of inferior vena cava filter (IVCF) in patients with a venous thromboembolism (VTE) have remained stable, their use continues to be frequent. Retrieval rates are still low, being particularly notable in the population with cancer. This study aims to review the rate of adherence to guidelines recommendation and to compare retrieval rates and complications in both cancer and non-cancer patients.

METHODS

A retrospective study was performed including 185 patients in whom an IVCF was placed in Hospital Clinic of Barcelona. Baseline characteristics, clinical outcomes, and IVCF-related outcomes were analyzed. A strongly recommended indication (SRI) was considered if it was included in all the revised clinical guidelines and non-strongly if it was included in only some.

RESULTS

Overall, 47 % of the patients had a SRI, without differences between groups. IVCF placement after 29 days from the VTE event was more frequent in the cancer group (46.1 vs. 17.7 %). Patients with cancer (48.1 % of the cohort) were older, with higher co-morbidity and bleeding risk. Anticoagulation resumption (75.3 % vs. 92.7 %) and IVCF retrieval (50.6 % vs. 66.7 %) were significantly less frequent in cancer patients. No significant differences were found regarding IVCF-related complications, hemorrhagic events and VTE recurrence.

CONCLUSIONS

SRI of IVCF placement was found in less than half of the patients. Cancer patients had higher rates of IVCF placement without indication and lower anticoagulation resumption and IVCF retrieval ratios, despite complications were similar in both groups.

Bismuth Nanoparticle and Polyhydroxybutyrate Coatings Enhance the Radiopacity of Absorbable Inferior Vena Cava Filters for Fluoroscopy-Guided Placement and Longitudinal Computed Tomography Monitoring in Pigs

Inferior vena cava filters (IVCFs) constructed with poly-p-dioxanone (PPDO) are promising alternatives to metallic filters and their associated risks and complications. Incorporating high-Z nanoparticles (NPs) improves PPDO IVCFs' radiopacity without adversely affecting their safety or performance. However, increased radiopacity from these studies are insufficient for filter visualization during fluoroscopy-guided PPDO IVCF deployment. This study focuses on the use of bismuth nanoparticles (BiNPs) as radiopacifiers to render sufficient signal intensity for the fluoroscopy-guided deployment and long-term CT monitoring of PPDO IVCFs. The use of polyhydroxybutyate (PHB) as an additional layer to increase the surface adsorption of NPs resulted in a 2-fold increase in BiNP coating (BiNP-PPDO IVCFs, 3.8%; BiNP-PPDO + PHB IVCFs, 6.2%), enabling complete filter visualization during fluoroscopy-guided IVCF deployment and, 1 week later, clot deployment. The biocompatibility, clot-trapping efficacy, and mechanical strength of the control PPDO (load-at-break, 6.23 ± 0.13 kg), BiNP-PPDO (6.10 ± 0.09 kg), and BiNP-PPDO + PHB (6.15 ± 0.13 kg) IVCFs did not differ significantly over a 12-week monitoring period in pigs. These results indicate that BiNP-PPDO + PHB can increase the radiodensity of a novel absorbable IVCF without compromising device strength. Visualizing the device under conventional radiographic imaging is key to allow safe and effective clinical translation of the device.

Dilemmas in anticoagulation and use of inferior vena cava filters in venous thromboembolism; a survey of Respiratory Physicians, Haematologists and Medical Oncologists and a review of the literature

Twenty percent of patients with Cancer Associated Thrombosis receive an inferior vena cava filter annually. Insertion is guided by practice guidelines, which do not specify or discuss the use of inferior vena cava filters in malignancy. Adherence to these guidelines is known to be variable. We aimed to see if there was consistent management of venous thromboembolism among Medical Oncologists/Haematologists and Respiratory Physicians, with respect to inferior vena cava filter use in the setting of suspected and confirmed malignancy. Medical Oncologists, Haematologists and Respiratory Physicians were surveyed with four theoretical cases. Case 1 concerns a patient who develops a pulmonary embolism following spinal surgery. Cases 2 and 4 explore the use of inferior vena cava filters in the setting of malignancy. Case 3 covers the role of inferior vena cava filters in recurrent thrombosis despite systemic anticoagulation. There were 56 responses, 32 (57%) Respiratory Physicians and 24 (43%) Haematologists/Oncologists. Respiratory Physicians were significantly more likely to insert an inferior vena cava filter in case 1 (p = 0.04) whilst Haematologists/Medical Oncologists were more likely to insert an inferior vena cava filter in case 3 (p = 0.03). No significant differences were found in cases 2 and 4. There were significant disparities in terms of type and timing of anticoagulation. Consistency of recommendations with guidelines was variable likely in part because guidelines are themselves inconsistent. The heterogeneity in responses highlights the variations in venous thromboembolism management, especially in Cancer Associated Thrombosis. International Societies should consider addressing inferior vena cava filter use specifically in the setting of Cancer Associated Thrombosis. Collaboration between interested specialities would assist in developing consistent, evidence-based guidelines for the use of inferior vena cava filters in the management of venous thromboembolism.