Retrievable vena cava filters: a clinical review

In vivo performance of gold nanoparticle-loaded absorbable inferior vena cava filters in a swine model

Absorbable inferior vena cava filters (IVCFs) offer a promising alternative to metallic retrievable filters in providing protection against pulmonary embolism (PE) for patients contraindicated for anticoagulant therapy. However, because absorbable filters are not radiopaque, monitoring of the filter using conventional X-ray imaging modalities (e.g. plain film radiographs, computed tomography [CT] and fluoroscopy) during deployment and follow-up is not possible and represents a potential obstacle to widespread clinical integration of the device. Here, we demonstrate that gold nanoparticles (AuNPs) infused into biodegradable filters made up of poly-p-dioxanone (PPDO) may improve device radiopacity without untoward effects on device efficacy and safety, as assessed in swine models for 12 weeks. The absorbable AuNP-infused filters demonstrated significantly improved visualization using CT without affecting tensile strength, in vitro degradation, in vivo resorption, or thrombus-capturing efficacy, as compared to similar non-AuNPs infused resorbable IVCFs. This study presents a significant advancement to the development of imaging enhancers for absorbable IVCFs.

In vivo imaging of radiopaque resorbable inferior vena cava filter infused with gold nanoparticles

Radiopaque resorbable inferior vena cava filter (IVCF) were developed to offer a less expensive alternative to assessing filter integrity in preventing pulmonary embolism for the recommended prophylactic period and then simply vanishes without intervention. In this study, we determined the efficacy of gold nanoparticle (AuNP)-infused poly-p-dioxanone (PPDO) as an IVCF in a swine model. Infusion into PPDO loaded 1.14±0.08 % AuNP by weight as determined by elemental analysis. The infusion did not alter PPDO's mechanical strength nor crystallinity (Kruskal-Wallis one-way ANOVA, p<0.05). There was no cytotoxicity observed (one-way ANOVA, p<0.05) when tested against RF24 and MRC5 cells. Gold content in PPDO was maintained at ~2000 ppm during the 6-week incubation in PBS at 37°C. As a proof-of-concept, two pigs were deployed with IVCF, one with AuNP-PPDO and the other without coating. Results show that the stent ring of AuNP-PPDO was highly visible even in the presence of iodine-based contrast agent and after clot introduction, but not of the uncoated IVCF. Autopsy at two weeks post-implantation showed AuNP-PPDO filter was endothelialized onto the IVC wall, and no sign of filter migration was observed. The induced clot was also still trapped within the AuNP-PPDO IVCF. As a conclusion, we successfully fabricated AuNP-infused PPDO IVCF that is radiopaque, has robust mechanical strength, biocompatible, and can be imaged effectively in vivo. This suggests the efficacy of this novel, radiopaque, absorbable IVCF for monitoring its position and integrity over time, thus increasing the safety and efficacy of deep vein thrombosis treatment.

Cost-benefit analysis of establishing an inferior vena cava filter clinic

PURPOSE

Adverse events associated with retrievable inferior vena cava filters (IVCFs) have generated an increased interest in improving IVCF retrieval rates to improve patient safety and quality care. This study aims to demonstrate the cost-benefit of implementing an IVCF clinic to improve patient care in an institution in the United States.

METHODS

An IVCF clinic was established at a single institution in September 2012 and for ten months referring physicians were contacted to facilitate retrieval when appropriate. Additionally, a retrospective review was conducted on filter placements over the eight preclinic months. Cost-benefit analysis was conducted by creating a model, which incorporated the average cost and reimbursement for permanent and retrievable IVCFs.

RESULTS

A total of 190 IVCFs (152 retrievable IVCFs and 38 permanent IVCFs) were implanted during the IVCF clinic period. Twenty-nine percent of the retrievable IVCFs were successfully retrieved compared to 10 of 119 retrievable IVCFs placed during the preclinic period (8.4%). Cost-benefit analysis, using the average of the institution's six most common reimbursement schedules, demonstrated an average net financial loss per permanent or retrievable IVCF not removed. However, a net financial gain was realized for each retrievable IVCF removed. The additional hospital cost to maintain the IVCF clinic was offset by removing an additional 3.1 IVCFs per year.

CONCLUSION

An IVCF clinic significantly increases retrieval rates, promotes patient safety, and is economically feasible. Given the adverse event profile of retrievable IVCFs, strategic efforts such as these ultimately can improve quality care for patients with in-dwelling IVCFs.

Radiopaque Resorbable Inferior Vena Cava Filter Infused with Gold Nanoparticles

Failure to remove a retrievable inferior vena cava (IVC) filter can cause severe complications with high treatment costs. Polydioxanone (PPDO) has been shown to be a good candidate material for resorbable IVC filters. However, PPDO is radioluscent under conventional imaging modalities. Thus, the positioning and integrity of these PPDO filters cannot be monitored by computed tomography (CT) or x-ray. Here we report the development of radiopaque PPDO IVC filters based on gold nanoparticles (AuNPs). Commercially available PPDO sutures were infused with AuNPs. Scanning electron microscopy analysis confirmed the presence of AuNP on the surface of PPDO. Micro-CT and x-ray images of the AuNP-infused PPDO sutures showed significant signal enhancement compared to untreated PPDO sutures. Elemental analysis showed that gold loading exceeded 2000 ppm. Tensile strength and in vitro cytotoxicity showed no significant difference between AuNP-infused and untreated PPDO. In a 10-week stability study, neither the gold content nor the radiopacity of the infused PPDO sutures significantly changed in the first 6 weeks. The increased attenuation of AuNP-infused PPDO sutures indicates their major advantage as a radiopaque resorbable filter material, as the radiopacity allows monitoring of the position and integrity of the filter, thereby increasing its safety and efficacy.

Inferior vena cava filters: current best practices

Venous thromboembolism (VTE) is a common cause of inpatient and outpatient morbidity and mortality. While anticoagulant therapy is considered the primary means of prevention and treatment of VTE, inferior vena cava filters (IVCFs) are often used as an alternative or adjunct to anticoagulation. With the advent of retrievable filters indications have liberalized, to include placement for primary prophylaxis in high-risk patients. However, this practice is based on limited evidence supporting their efficacy in preventing clinically relevant outcomes. Since indiscriminate use of IVCFs can be associated with net patient harm and increased health care costs, knowledge of the literature surrounding IVCF utilization is critical for providers to adopt best practices. In this review, we will provide an overview of the literature as it relates to specific clinical questions that arise when considering IVCF utilization in the prevention and treatment of VTE. Practice-based recommendations will be reviewed to provide the clinician with guidance on challenging clinical scenarios.

Submassive pulmonary embolism

Pulmonary embolism (PE) is a common diagnosis in critical care. Depending on the severity of clot burden, the clinical picture ranges from nearly asymptomatic to cardiovascular collapse. The signs and symptoms of PE are nonspecific. The clinician must have a high index of suspicion to make the diagnosis. PE is risk stratified into 3 categories: low-risk, submassive, and massive. Submassive PE remains the most challenging with regard to initial and long-term management. Little consensus exists as to the appropriate tests for risk stratification and therapy. This article reviews the current literature and a suggested approach to these patients.

Retrievable inferior vena cava filters in patients with cancer are safe but are they beneficial?

The availability and insertion of permanent and retrievable inferior vena cava filter devices have increased substantially over the past decade. Our retrospective study provides the first detailed assessment of the safety and efficacy of retrievable inferior vena cava filters in a large cohort of cancer patients with predominantly advanced malignancies. We retrospectively reviewed the medical records of consecutive patients with the diagnosis of cancer who underwent inferior vena cava filter placement at a single academic medical center from 2007 to 2012 with special attention to safety, recurrent venous thromboembolism, and survival data. Three hundred thirty-seven cancer patients were included in the analysis. Gastrointestinal, lung, and genitourinary malignancies were the most commonly represented malignancies [94 (27.8 %), 70 (20.8 %), and 37 (10.9 %) patients, respectively]. Immediate complications were diagnosed in one of 258 (1 %) evaluable patients following placement of a retrievable filter. Delayed complications occurred in 23 of 258 (8 %) patients. The 7, 14, 30, 90, and 365 day post-filter survival rates for patients with stage IV cancer were 0.91, 0.86, 0.71, 0.52, and 0.29, respectively. Patients with lung and gastrointestinal tumors demonstrated a significantly reduced post-filter survival rate compared with those with genitourinary, brain, and breast cancers. Retrievable and non-retrievable inferior vena cava filters are associated with an overall low rate of complications in patients with cancer. However, survival rates following filter placement are poor in this patient population.

Vena caval thrombosis after trauma to the liver

Thrombosis of the inferior vena cava due to compression of the inferior vena cava by a hepatic haematoma is seemingly rare. We present a case of a 56-year-old female with a hepatic haematoma after blunt trauma that caused this type of compression. The constriction resulted in the formation of an inferior vena cava thrombus, and considering the contraindication to anticoagulation, we placed a retrievable inferior vena cava filter under standard fluoroscopy. This case stresses the need for systematic investigation of the abdomen, especially after a blunt trauma, which can cause compression of the inferior vena cava. Furthermore, inferior vena cava thrombosis should be considered in patients with compression of the inferior vena cava due to hepatic haematoma.

The Role for Prophylaxis Inferior Vena Cava Filters in Patients Undergoing Bariatric Surgery: Replacing Anecdote with Evidence

The number of patients choosing surgical alternatives for weight reduction continues to increase. Despite common thromboembolic preventive methods, which include perioperative subcutaneous heparin injections, early mobilization, and sequential compression devices, postoperative deep vein thrombosis/pulmonary embolism remains a devastating complication after bariatric surgery. The role prophylactic inferior vena cava (IVC) filters may play in bariatric surgery remains controversial, and this article aims to address the risks and benefits of prophylactic IVC filters in high-risk bariatric patients and suggest an evidence-based algorithm for their use.

High inferior vena cava thrombosis in a 16-year-old postpartum patient: a case report

Postpartum inferior vena cava (IVC) thrombosis is a rare, but potentially life-threatening disorder. Here we reported one case of the youngest woman to date who presented with massive IVC thrombus extending from deep veins of the right leg to the level of the 11th thoracic vertebra, associated with asymptomatic pulmonary embolism.

Death and venous thromboembolism after lower extremity amputation

BACKGROUND

Lower extremity amputation is often performed in patients with end-stage vascular disease and is considered a high-risk procedure. Uncertainty exists about the rate of venous thromboembolism (VTE) in these patients.

OBJECTIVES

To establish the incidence of death and venous thromboembolism after lower extremity amputation.

METHODS

A prospective cohort study was performed to establish the incidences of death and VTE after lower extremity amputation, as detected by bilateral complete compression ultrasonography and ventilation-perfusion scintigraphy performed preoperatively and around day 14 postoperatively. Standard low-molecular-weight heparin thromboprophylaxis was given during the study period. A secondary outcome was the incidences of mortality and symptomatic venous thromboembolic complications during 8 weeks of postoperative follow-up.

RESULTS

Forty-nine patients (53 amputations) were ultimately included in the intention-to-treat analysis. Five patients died within the 2-week period and an additional seven patients died during the 8 weeks clinical follow-up period. The total mortality rate therefore was 12 of 53 amputations [22.6%; 95% confidence interval (CI), 12.3-36.2%]. Six patients developed pulmonary embolisms (of which two were fatal) and one patient developed an asymptomatic contralateral distal deep venous thrombosis, resulting in a total VTE rate of 7 out of 53 amputations (13.2%; 95% CI, 5.47-25.3%).

CONCLUSION

Lower extremity amputation is accompanied by a high mortality rate from sepsis, and respiratory and vascular causes. This study shows that VTE substantially contributes to the morbidity and mortality after lower extremity amputation despite adequate pharmacological thromboprophylaxis in this vulnerable population of patients.