Thrombus Signal on T1-Weighted Black-Blood MR Predicts Outcomes of Catheter-Directed Thrombolysis in Acute Deep Vein Thrombosis

OBJECTIVES

 Catheter-directed thrombolysis (CDT) is an effective therapy for acute deep vein thrombosis (DVT). However, predicting the CDT outcomes remains elusive. We hypothesized that the thrombus signal on T1-weighted black-blood magnetic resonance (MR) can provide insight into CDT outcomes in acute DVT patients.

METHODS

 A total of 117 patients with acute iliofemoral DVT were enrolled for T1-weighted black-blood MR before CDT in this prospective study. Based on the signal contrast between thrombus and adjacent muscle, patients were categorized into the iso-intense thrombus (Iso-IT), hyper-intense thrombus (Hyper-IT), and mixed iso-/hyper-intense thrombi (Mixed-IT) groups. Immediate treatment outcome (i.e., vein patency) and long-term treatment outcome (i.e., the incidence rate of postthrombotic syndrome) were accessed by the same expert. Histological analysis and iron quantification were performed on thrombus samples to characterize the content of fibrin, collagen, and the ratio of Fe³⁺ to total iron.

RESULTS

 Compared to Mixed-IT and Hyper-IT groups, the Iso-IT group had the best lytic effect (90.5 ± 1.6% vs. 78.4 ± 2.6% vs. 46.5 ± 3.3%, p < 0.001), lowest bleeding ratio (0.0 vs. 11.8 vs. 13.3, p < 0.001), and the lowest incidence rate of postthrombotic syndrome on 24 months (3.6 vs. 18.4 vs. 63.4%, p < 0.001) following CDT. The Iso-IT group had a significantly lower ratio of Fe³⁺ to total iron (93.1 ± 3.2% vs. 97.2 ± 2.1%, p = 0.034) and a higher content of fibrin (12.5 ± 5.3% vs. 4.76 ± 3.18%, p = 0.023) than Hyper-IT.

CONCLUSION

 Thrombus signal characteristics on T1-weighted black-blood MR is associated with CDT outcomes and possesses potential to serve as a noninvasive approach to guide treatment decision making in acute DVT patients.

KEY POINTS

· Thrombus signal on T1-weighted black-blood MR is associated with lytic therapeutic outcome in acute DVT patients.. · Presence of iso-intense thrombus revealed by T1-weighted black-blood MRI is associated with successful thrombolysis, low bleeding ratio, and low incidence of the postthrombotic syndrome.. · T1-weighted thrombus signal characteristics may serve as a noninvasive imaging marker to predict CDT treatment outcomes and therefore guide treatment decision making in acute DVT patients..

Safety and Success Rates of Excimer Laser Sheath-Assisted Retrieval of Embedded Inferior Vena Cava Filters

IMPORTANCE

Despite historically high rates of use, most inferior vena cava (IVC) filters are not retrieved. The US Food and Drug Administration safety communications recommended retrieval when the IVC filter is no longer indicated out of concern for filter-related complications. However, failure rates are high when using standard techniques for retrieval of long-dwelling filters, and until recently, there have been no devices approved for retrieval of embedded IVC filters.

OBJECTIVE

To evaluate the safety and success of excimer laser sheath-assisted retrieval of embedded IVC filters.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective, multicenter, clinical cohort study of excimer laser sheath-assisted IVC filter retrievals from 7 US sites was conducted between March 1, 2012, and February 28, 2021, among 265 patients who underwent IVC filter retrieval using the laser. Patients were substratified between a high-volume single center and a multicenter data set. A blinded physician committee adjudicated reported complications and their association with use of the laser.

EXPOSURES

Retrieval of IVC filters using excimer laser sheath.

MAIN OUTCOMES AND MEASURES

The primary safety end point was device-related major complication rate (Society of Interventional Radiology categories C to F, which included any adverse event associated with morbidity or disability that increases the level of care, results in hospital admission, or substantially lengthens the hospital stay). The primary success end point was technical success of IVC filter retrieval. The primary end points were compared with literature-derived, meta-analysis-suggested target performance goals.

RESULTS

The single-center experience included 139 participants (mean [SD] age, 52 [16] years; 78 female participants [56.1%]), and the multicenter experience included 126 participants (mean [SD] age, 52 [16] years; 75 female participants [59.5%]). The device-related major complication rate was 2.9% (4 of 139; 95% CI, 0.8%-7.2%; P = .001) for the single-center experience and 4.0% (5 of 126; 95% CI, 1.3%-9.0%; P = .01) for the multicenter experience, both of which were significantly lower than the primary safety performance goal (10%). No major complications were considered to be definitively associated with use of the laser. The technical success rate was 95.7% (133 of 139; 95% CI, 90.8%-98.4%; P = .007) for the single-center experience and 95.2% (120 of 126; 95% CI, 89.9%-98.2%; P = .02) for the multicenter experience, both of which were significantly higher than the primary performance goal (89.4%).

CONCLUSIONS AND RELEVANCE

This cohort study demonstrated high technical success and low complication rates of excimer laser sheath-assisted retrieval of embedded IVC filters in centers with variable case volume and experience, which suggests a wide applicability of the technique with proper training. The excimer laser sheath offers physicians a valuable tool for retrieval of challenging embedded IVC filters.

High Prevalence of Transjugular Intrahepatic Portosystemic Shunt Creation Without Prior Endoscopy During Acute Variceal Bleeding Hospitalization in the United States

Current clinical guidelines by both American Association for the Study of Liver Disease and European Association for the Study of the Liver recommend endoscopy in all patients admitted with acute variceal bleeding within 12 hours of admission. Transjugular intrahepatic portosystemic shunt (TIPS) creation may be considered in patients at high risk if hemorrhage cannot be controlled endoscopically. We conducted a cross-sectional observational study to assess how frequently TIPS is created for acute variceal bleeding in the United States without preceding endoscopy. Adult patients undergoing TIPS creation for acute variceal bleeding in the United States (n = 6,297) were identified in the last 10 available years (2007-2016) of the National Inpatient Sample. Hierarchical logistic regression was used to examine the relationship between endoscopy nonutilization and hospital characteristics, controlling for patient demographics, income level, insurance type, and disease severity. Of 6,297 discharges following TIPS creation for acute variceal bleeding in the United States, 31% (n = 1,924) did not receive first-line endoscopy during the same encounter. Rates of "no endoscopy" decreased with increasing population density of the hospital county (nonmicropolitan counties 43%, n = 114; mid-size metropolitan county 35%, n = 513; and central county with >1 million population 23%, n = 527) but not by hospital teaching status (n = 1,465, 32% teaching vs. n = 430, 26% nonteaching; P = 0.10). Higher disease mortality risk (odds ratio, 0.42; 95% confidence interval, 0.22-0.80; P = 0.02) was associated with lower odds of noncompliance. Conclusion: One third of all patients undergoing TIPS creation for acute variceal bleeding in the United States do not receive first-line endoscopy during the same encounter. Patients admitted to urban hospitals are more likely to receive guideline-concordant care.

Comparative efficacy and safety of the Captus device for inferior vena cava filter retrieval

PURPOSE

Retrievable inferior vena cava filters (IVCF) have been increasingly used for mechanical pulmonary embolism prophylaxis since their development. The Captus Vascular Retrieval System (Avantec Vascular, Sunnyvale, California) is a new device developed for retrieval of IVCF. This study compared the safety and efficacy of the new Captus device against the existing EnSnare Endovascular Snare System (Merit Medical, South Jordan, Utah) for IVCF retrieval.

METHODS

Patients undergoing IVCF retrieval at a single institution between July 2015 and July 2020 were retrospectively identified. All adult patients (>18 years) undergoing filter retrieval with either Captus or Ensnare were included. Technical success and complications were compared by device. A complexity score was assigned to each case to adjust for selection bias. Logistic regression was used to model the association between device type and primary technical success.

RESULTS

99 IVCF retrievals met inclusion criteria, 59 with Captus and 40 with Ensnare. The majority of the cohort consisted of low complexity cases (n = 51, 86% Captus versus n = 31, 78% Ensnare; p = 0.28). Technical success for low and medium complexity retrievals was 88% and 62% with Captus and 96% and 33% with Ensnare. There was no significant association between device type and technical success, adjusting for case complexity (Captus OR 0.55, 95% CI 0.08-2.72, p = 0.49). There were no device-related complications.

CONCLUSION

No statistically significant difference in device technical success or complications between the Ensnare and Captus devices for uncomplicated IVCF retrieval.

PRECIS

The Captus Vascular Retrieval System is a new device for IVC filter retrieval which has similar technical success to the existing EnSnare.

Ethnoracial Disparity in Hospital Survival following Transjugular Intrahepatic Portosystemic Shunt Creation for Acute Variceal Bleeding in the United States

PURPOSE

To investigate the magnitude of racial/ethnic differences in hospital mortality after transjugular intrahepatic portosystemic shunt (TIPS) creation for acute variceal bleeding and whether hospital care processes contribute to them.

METHODS

Patients aged ≥18 years undergoing TIPS creation for acute variceal bleeding in the United States (n = 10,331) were identified from 10 years (2007-2016) available in the National Inpatient Sample. Hierarchical logistic regression was used to examine the relationship between patient race and inpatient mortality, controlling for disease severity, treatment utilization, and hospital characteristics.

RESULTS

A total of 6,350 (62%) patients were White, 1,780 (17%) were Hispanic, and 482 (5%) were Black. A greater proportion of Black patients were admitted to urban teaching hospitals (Black, n = 409 (85%); Hispanic, n = 1,310 (74%); and White, n = 4,802 (76%); P < .001) and liver transplant centers (Black, n = 215 (45%); Hispanic, n = 401 (23%); and White, n = 2,267 (36%); P < .001). Being Black was strongly associated with mortality (Black, 32% vs non-Black, 15%; odds ratio, 3.0 [95% confidence interval, 1.6-5.8]; P = .001), as assessed using the risk-adjusted regression model. This racial disparity disappeared in a sensitivity analysis including only patients with a maximum Child-Pugh score of 13 (odds ratio 1.2 [95% confidence interval, 0.4-3.6]; P = .68), performed to compensate for the absence of Model for End-stage Liver Disease scores. Ethnoracial differences in access to teaching hospitals, liver transplant centers, first-line endoscopy, and transfusion did not significantly contribute (P > .05) to risk-adjusted mortality.

CONCLUSIONS

Black patients have a 2-fold higher inpatient mortality than non-Black patients following TIPS creation for acute variceal bleeding, possibly related to greater disease severity before the procedure.

Cost Analysis of Dialysis Access Maintenance Interventions across Physician Specialties in U.S. Medicare Beneficiaries

Background Dialysis maintenance interventions account for billions of dollars in U.S. Medicare spending and are performed by multiple medical specialties. Whether Medicare costs differ by physician specialty is, to the knowledge of the authors, not known. Purpose To assess patency-adjusted costs of endovascular dialysis access maintenance by physician specialty. Materials and Methods In this retrospective longitudinal cohort study, patients who were beneficiaries of Medicare undergoing their first arteriovenous access placement in 2009 were identified by using billing codes in the 5% Limited Data Set. By tracking their utilization data through 2014, postintervention primary patency and aggregate payments associated with maintenance interventions were calculated. Unadjusted payments per year of access patency gain were compared across physician specialty. A general linear mixed-effects model adjusted for covariates was used, as follows: patient characteristics, access type (fistula vs graft), clinical severity, type of intervention (angioplasty, stent, thrombolysis), clinical location (hospital outpatient vs office-based laboratory), and resource utilization (operating room use, anesthesia use). Results First arteriovenous access was performed in 1479 beneficiaries (mean age, 63 years ± 15 [standard deviation]; 820 men) in 2009. Through 2014, 8166 maintenance interventions were performed in this cohort. Unadjusted mean Medicare payments for each incremental year of patency were as follows: $71 000 for radiologists, $89 000 for nephrologists, and $174 000 for surgeons. Billing for operating room (41.8% [792 of 1895], surgery; 10.2% [277 of 2709], nephrology; and 31.1% [1108 of 3562], radiology) and anesthesia (19.9% [377 of 1895], surgery; 2.6% [70 of 2709], nephrology; 4.7% [170 of 3562], radiology) varied by specialty and accounted for 407% and 132% higher payments, respectively. After adjusting for clinical severity and location, type of intervention, and resource utilization, nephrologists and surgeons had 59% (95% confidence interval: 44%, 73%; P < .001) and 57% (95% confidence interval: 43%, 72%; P < .001) higher payments, respectively, for the same patency gain compared with radiologists. Operating room use and anesthesia services were major drivers of higher cost, with 407% (95% confidence interval: 374%, 443%; P < .001) and 132% (95% confidence interval: 116%, 150%; P < .001) higher costs, respectively. Conclusion Patency-adjusted payments for hemodialysis access maintenance differed by physician specialty, driven partly by discrepant rates of billing for operating room and anesthesia use. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by White in this issue.

Excimer Laser Sheath-Assisted Retrieval of "Closed-Cell" Design Inferior Vena Cava Filters

Background Numerous reports have shown that inferior vena cava filters are associated with clinically significant adverse events. Complicating factors, such as caval incorporation, may lead to technical challenges at retrieval. The use of advanced techniques including the laser sheath have increased technical success rates; however, the data are limited on which filter types necessitate and benefit from its use. Methods and Results From October 2011 to September 2019, patients with inferior vena cava filter dwell times >6 months or with prior failed retrievals were considered for laser sheath-assisted retrieval. Standard and nonlaser advanced retrieval techniques were attempted first; if the filter could not be safely or successfully detached from the caval wall using these techniques, the laser sheath was used. Technical success, filter type, necessity for laser sheath application based on "open" versus "closed-cell" filter design, dwell times, and adverse events were evaluated. A total of 441 patients (216 men; mean age, 54 years) were encountered. Mean dwell times for all filters was 56.6 months, 54.4 among closed-cell filters and 58.5 among open-cell filters (P=0.63). Technical success of retrieval was 98%, with the laser sheath required in 143 cases (40%). Successful retrieval of closed-cell filters required laser sheath assistance in 60% of cases as compared with 7% of open-cell filters (odds ratio, 20.1; P<0.01). In closed-cell inferior vena cava filters, dwell time was significantly associated with need for laser, requiring it in 64% of retrievals with dwell times >6 months (P=0.01). One major adverse event occurred among laser sheath retrievals when a patient required a 2-day inpatient admission for a femoral access site hemorrhage. Conclusions Closed-cell filters may necessitate the use of the laser sheath for higher rates of successful and safe retrieval.

A Primer to Understanding the Elements of Medical Malpractice

According to a 2017 survey of 4,000 physicians across 25 different specialties in the United States, 55% of respondents report having been sued at least once, with nearly half of them having been sued multiple times. In addition, procedural specialists are far more likely to be sued. As a procedural-driven specialty, interventional radiology (IR) practitioners are subject to these statistics. While the focus of all IR practices is providing the highest quality care safely and efficiently, medical errors and complications are unavoidable. Understanding the process of medical malpractice litigation is necessary to develop strategies on how best to avoid and mitigate the hardships of the process.

Defining Prolonged Dwell Time: When Are Advanced Inferior Vena Cava Filter Retrieval Techniques Necessary? An Analysis in 762 Procedures

BACKGROUND

Despite growth in placement of retrievable inferior vena cava filters, retrieval rates remain low. Filters with extended implantation times present a challenge to retrieval, where standard techniques often fail. The development of advanced retrieval techniques has positively impacted retrieval of retrievable inferior vena cava filters with prolonged dwell times; however, there is no precise definition of the time point when advanced techniques become necessary. We aim to define prolonged retrievable inferior vena cava filters dwell time by determining the inflection point when the risk of standard retrieval technique failure increases significantly, necessitating advanced retrieval techniques to maintain overall technical success of retrieval.

METHODS AND RESULTS

From January 2009 to April 2015, 762 retrieval procedures were identified from a prospectively acquired database. We assessed patient age/sex, filter dwell time, procedural technical success, the use of advanced techniques, and procedure-related adverse events. Overall retrieval success rate was 98% (n=745). When standard retrieval techniques failed, advanced techniques were used; this was necessary 18% of the time (n=138). Logistic regression identified that dwell time was the only risk factor for failure of standard retrieval technique (odds ratio, 1.08; 95% confidence interval, 1.05-1.10; P<0.001). Spline function regression analysis demonstrated that if dwell time exceeded 7 months, the risk of standard technique failure was 40.9%. Adverse events occurred at a rate of 2% (n=18; 15 minor and 3 major).

CONCLUSIONS

The necessity of advanced techniques to maintain technical success of retrieval increases with dwell time. Patients with retrievable inferior vena cava filters in place beyond 7 months may benefit from referral to centers with expertise in advanced filter retrieval.

IVC filter placements in children: nationwide comparison of practice patterns at adult and children's hospitals using the Kids' Inpatient Database

BACKGROUND

Inferior vena cava (IVC) filter placement in children has been described in literature, but there is variability with regard to their indications. No nationally representative study has been done to compare practice patterns of filter placements at adult and children's hospitals.

OBJECTIVE

To perform a nationally representative comparison of IVC filter placement practices in children at adult and children's hospitals.

MATERIALS AND METHODS

The 2012 Kids' Inpatient Database was searched for IVC filter placements in children <18 years of age. Using the International Classification of Diseases, 9th Revision (ICD-9) code for filter insertion (38.7), IVC filter placements were identified. A small number of children with congenital cardiovascular anomalies codes were excluded to improve specificity of the code used to identify filter placement. Filter placements were further classified by patient demographics, hospital type (children's and adult), United States geographic region, urban/rural location, and teaching status. Statistical significance of differences between children's or adult hospitals was determined using the Wilcoxon rank sum test.

RESULTS

A total of 618 IVC filter placements were identified in children <18 years (367 males, 251 females, age range: 5-18 years) during 2012. The majority of placements occurred in adult hospitals (573/618, 92.7%). Significantly more filters were placed in the setting of venous thromboembolism in children's hospitals (40/44, 90%) compared to adult hospitals (246/573, 43%) (P<0.001). Prophylactic filters comprised 327/573 (57%) at adult hospitals, with trauma being the most common indication (301/327, 92%). The mean length of stay for patients receiving filters was 24.5 days in children's hospitals and 18.4 days in adult hospitals.

CONCLUSION

The majority of IVC filters in children are placed in adult hospital settings. Children's hospitals are more likely to place therapeutic filters for venous thromboembolism, compared to adult hospitals where the prophylactic setting of trauma predominates.

Retrievable IVC Filters: Comprehensive Review of Device-related Complications and Advanced Retrieval Techniques

Use of retrievable inferior vena cava filters (RIVCFs) has grown exponentially since their introduction into clinical practice, but many of these devices are not retrieved. Some are not retrieved due to poor clinical follow-up, but other devices remain in situ for extended periods because they present significant technical challenges during retrieval. Because of these and other factors, many of these devices were thus left in place permanently. However, recent data have placed a renewed emphasis on device retrieval due to increased risk of RIVCF-related complications, which are positively correlated with filter dwell time. Development of advanced filter retrieval techniques has had a significant impact on the removal of embedded RIVCFs, permitting retrieval of the majority of devices. The purpose of this article is to present an imaging and data review of the dominant device-related factors that complicate RIVCF retrieval and to describe the relevant advanced retrieval techniques to manage these factors. RIVCF imaging is frequently encountered in daily clinical practice via various imaging modalities. Therefore, diagnostic radiologists can play a vital role in identifying filter-related issues. Familiarity with the context for managing these issues in the interventional suite is essential for improving triage and care of patients with RIVCFs. ^© RSNA, 2017.

Erratum: Hepatic Radioembolization Complicated by Abscess

[This corrects the article DOI: 10.1055/s-0031-1280669.].

The law of unintended consequences: current design challenges in inferior vena cava filters

INTRODUCTION

Venous thromboembolic disease (VTD) encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE) is a commonly encountered condition with potentially fatal sequelae. When unable to be adequately anticoagulated, patients require a mechanical means to prevent PE. This review discusses the history of inferior vena cava interruption and the development of inferior vena cava filters (IVCF). Areas covered: Milestone innovations in the mechanical treatment of VTD, their successes and shortcomings are discussed. The unforeseen complications that have occurred with implantation of IVCF have a profound impact on the present utilization of retrievable filters. Particular attention is dedicated to the evidence for safe and effective use of IVCF and the challenges presented to further improvement of these technologies. Expert commentary: While evidence suggests that IVCF are effective in preventing PE, the recent 'de-volution' from permanent to retrievable design has unleashed an epidemic device-related complications. Retrievable filter design is reliant on a 'Goldilocks' premise: make the device stable (so it doesn't migrate), but not too stable (so you can still retrieve it). Efforts must be aimed at optimizing utilization using decision support tools, meticulous follow up after deployment, and conversion from retrievable to permanent devices if the patient requires lifelong mechanical prophylaxis.

Why Temporary Filters Are Not Removed: Clinical Predictors in 1,000 Consecutive Cases

BACKGROUND

Compared to permanent inferior vena cava (IVC) filters, higher complication rates occur with long-term use of temporary IVC filters. We aimed to identify patient clinical factors at the time of placement that could predict failure to remove a temporary IVC filter.

METHODS

A retrospective review was performed of both vascular surgery and interventional radiology prospective databases between December 2008 and December 2013. We analyzed a total number of 1,024 consecutive, temporary IVC filters stratified by whether retrieval was attempted or made permanent. Univariate, multivariate, and prediction modeling analyses with internal validation were performed on abstracted data, which included risk factors, treatment modalities, and indications for IVC filter placement.

RESULTS

Of 1,024 temporary IVC filters, removal was attempted in 60% and no attempt at removal (kept permanent) in 40%. Of the 619 with attempted removal, the overall successful retrieval rate was 95%. The majority of filters were not attempted to be removed because of persistent filter indications (360 cases). Risk factors associated with IVC filter permanence included male sex, older age, history, or indication of venous thromboembolism (VTE) with inability to anticoagulate, malignancy, and neurologic condition. Risk factors most predictive of permanence in the multivariate model were malignancy (odds ratio [OR]: 3.0, P < 0.001) or neurologic disorder (OR: 2.69, P = 0.0005). Validation revealed our model had a sensitivity of 60.4% and specificity of 69.9%.

CONCLUSIONS

Our study shows that patients who are more likely to have a temporary IVC filter kept permanent are more likely to be older males with a history of malignancy, neurologic condition, or VTE. These factors are also predictive of permanence and can be used in our predictive model to provide insight into the significant preoperative risk factors that should play into the decision-making process.

Anatomic and Technical Considerations: Inferior Vena Cava Filter Placement

Inferior vena cava (IVC) filters play an important role in preventing pulmonary embolism in patients with deep venous thrombosis. When preparing for IVC filter placement, there are several important anatomic and technical considerations. The IVC has complex embryologic origins, and normal variants are relatively common which may necessitate a change in technique or approach. When performing the procedure, the choice in imaging modality for deployment, location of deployment, and route of access must be considered. The pediatric and pregnant populations present unique situations that require special consideration and close examination of indications and contraindications.

A Dedicated Inferior Vena Cava Filter Service Line: How to Optimize Your Practice

Despite the increased placement of retrievable inferior vena cava filters (rIVCFs), efforts to remove these devices are not commensurate. The majority of rIVCFs are left in place beyond their indicated usage, and often are retained permanently. With a growing understanding of the clinical issues associated with these devices, the United States Food and Drug Administration (FDA) has prompted clinicians to remove rIVCF when they are no longer indicated. However, major obstacles exist to filter retrieval, chief among them being poor clinical follow-up. The establishment of a dedicated IVC filter service line, or clinic, has been shown to improve filter retrieval rates. Usage of particular devices, specifically permanent versus retrievable filters, is enhanced by prospective physician consultation. In this article, the rationale behind a dedicated IVC filter service line is presented as well as described the structure and activities of the authors' IVC filter clinic; supporting data will also be provided when appropriate.

Permanent versus Retrievable Inferior Vena Cava Filters: Rethinking the "One-Filter-for-All" Approach to Mechanical Thromboembolic Prophylaxis

Inferior vena cava (IVC) filtration for thromboembolic protection is not without risks, and there are important differences among commercially available IVC filters. While retrievable filters are approved for permanent implantation, they may be associated with higher device-related complications in the long term when compared with permanent filters. Prospective patient selection in determining which patients might be better served by permanent or retrievable filter devices is central to resource optimization, in addition to improved clinical follow-up and a concerted effort to retrieve filters when no longer needed. This article highlights the differences between permanent and retrievable devices, describes the interplay between these differences and the clinical indications for IVC filtration, advises against a "one-filter-for-all" approach to mechanical thromboembolic prophylaxis, and discusses strategies for optimizing personalized device selection.

The Role of Inferior Vena Cava Filters in Cancer Patients

Cancer induces a hypercoagulable state and renders patients susceptible to venous thromboembolism. While anticoagulation remains the mainstay of treatment, many of these patients require placement of an inferior vena cava (IVC) filter, often due to a contraindication to or failure of anticoagulation. In this article, the available data on IVC filter usage in cancer patients will be reviewed.

Retrieval of Inferior Vena Cava Filters: Technical Considerations

Placement of retrievable inferior vena cava filters has seen rapid growth since their introduction into clinical practice. When retrieved, these devices offer the notional benefit of temporary protection from pulmonary embolism related to lower extremity deep venous thrombosis, and mitigation of filter-related deep venous thrombosis. When promptly removed after the indication for mechanical prophylaxis is no longer present, standard endovascular retrieval techniques are frequently successful. However, the majority of these devices are left in place for extended periods of time, which has been associated with greater device-related complications when left in situ, and failure of standard techniques when retrieval is attempted. The development of advanced retrieval techniques has had a positive impact on retrieval of these embedded devices. In this article, technical considerations in the retrieval of such devices, with an emphasis on advanced techniques to facilitate retrieval of embedded devices, are discussed.

The Role of Potentially Retrievable Inferior Vena Cava Filters in High-Risk Patients Undergoing Joint Arthroplasty

INTRODUCTION

Some patients undergoing total joint arthroplasty are at increased risk for venous thromboembolism (VTE). The aim of the present study was to evaluate the safety and efficacy of prIVCF in preventing PE in patients undergoing joint replacement surgery who are at high-risk for VTE.

MATERIALS AND METHODS

In this prospective, IRB-approved study, prIVCF were placed in consecutive patients who met specific high-risk criteria (history of VTE or hypercoaguable state) prior to total joint arthroplasty. Patients were followed until the IVC filter was removed. Outcomes and complications were recorded per Society of Interventional Radiology guidelines.

RESULTS

One hundred and nine potentially retrievable IVC filters were placed in 105 patients, who all subsequently underwent joint arthroplasty. One hundred eight IVC filters (98.9%) were retrieved successfully in a mean time of 44.1 days (range 13-183 days). There was 1 failed IVC filter retrieval attempt (0.9%) at 46 days post implantation. Two patients (1.9%) presented with recurrent PE and were successfully treated with anticoagulation prior to IVC filter retrieval. There were no fatalities from perioperative PE. In 1 patient (0.9%), a fractured filter leg had embolized during retrieval.

CONCLUSION

Potentially retrievable IVC filters are safe and effective for prophylaxis against PE in patients at high-risk for VTE undergoing joint arthroplasty.

Percutaneous Management of Malignant Biliary Obstruction

Malignancy resulting in impaired biliary drainage includes a number of diagnoses familiar to the interventional radiologist. Adequate drainage of such a system can significantly improve patient quality of life, and can facilitate the further treatment options and care of such patients. In the setting of prior instrumentation, cholangitis can present as an urgent indication for drainage. Current initial interventional management of malignant biliary duct obstruction frequently includes endoscopic or percutaneous intervention, with local practices and preprocedural imaging guiding interventional approaches and subsequent management. This article addresses the indications for percutaneous drainage, technical considerations in performing such drainage, and specific techniques useful in attempting to achieve clinical end points in patients with malignant biliary duct obstruction.

Comparative study of staging systems for hepatocellular carcinoma in 428 patients treated with radioembolization

PURPOSE

To compare the utility of different staging systems and analyze independent predictors of survival in patients with hepatocellular carcinoma (HCC) treated with yttrium-90 ((90)Y) radioembolization.

MATERIALS AND METHODS

During the period 2004-2011, 428 patients with HCC were treated with (90)Y radioembolization. All patients were staged prospectively by the following staging systems: Child-Turcotte-Pugh (CTP), United Network for Organ Sharing, Barcelona Clinic Liver Cancer (BCLC), Okuda classification, Cancer of the Liver Italian Program (CLIP), Groupe d'Etude et de Traitement du Carcinome Hepatocellulaire, Chinese University Prognostic Index, and Japan Integrated Staging. The ability of the staging systems to predict survival was assessed. The staging systems were compared using Cox proportional hazards regression model, linear regression, Akaike information criterion (AIC), and concordance index (C-index). Univariate and multivariate analyses were employed to assess independent predictors of survival.

RESULTS

When tested independently, all staging systems exhibited significant ability to discriminate early (long survival) from advanced (worse survival) disease. CLIP provided the most accurate information in predicting survival outcomes (AIC = 2,993, C-index = 0.8503); CTP was least informative (AIC = 3,074, C-index = 0.6445). Independent predictors of survival included Eastern Cooperative Oncology Group performance status grade 0 (hazard ration [HR], 0.56; confidence interval [CI], 0.34-0.93), noninfiltrative tumors (HR, 0.62; CI, 0.44-0.89), absence of portal venous thrombosis (HR, 0.60; CI, 0.40-0.89), absence of ascites (HR, 0.56; CI, 0.40-0.76), albumin ≥ 2.8 g/dL (HR, 0.72; CI, 0.55-0.94), alkaline phosphatase ≤ 200 U/L (HR, 0.68; CI, 0.50-0.92), and α-fetoprotein ≤ 200 ng/mL (HR, 0.67; CI, 0.51-0.86).

CONCLUSIONS

CLIP was most accurate in predicting survival in patients with HCC. Given that not all patients receive the recommended BCLC treatment strategy, this information is relevant for clinical trial design and predicting long-term outcomes after (90)Y radioembolization.

Comparison of complication rates associated with permanent and retrievable inferior vena cava filters: a review of the MAUDE database

PURPOSE

To compare the safety of permanent and retrievable inferior vena cava (IVC) filters by reviewing the U.S. Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database.

MATERIALS AND METHODS

The MAUDE database was reviewed from January 1, 2009, to December 31, 2012. Product class search criteria were "filter, intravascular, cardiovascular." Type of device used and specific adverse events (AEs) were recorded.

RESULTS

For the period January 2009-December 2012, 1,606 reported AEs involving 1,057 IVC filters were identified in the MAUDE database . Of reported AEs, 1,394 (86.8%) involved retrievable inferior vena cava filters (rIVCFs), and 212 (13.2%) involved permanent inferior vena cava filters (pIVCFs) (P < .0001). Reported AEs included fracture, migration, limb embolization, tilt, IVC penetration, venous thromboembolism and pulmonary embolism, IVC thrombus, and malfunctions during placement. Each specific AE was reported with significantly higher frequency in rIVCFs compared with pIVCFs. The most common reported complication with rIVCFs was fracture, whereas the most commonly reported complications with pIVCFs were placement malfunctions. For rIVCFs, the most commonly reported AE varied depending on filter brand.

CONCLUSIONS

The MAUDE database reveals that complications occur with significantly higher frequency with rIVCFs compared with pIVCFs. This finding suggests that the self-reported complication rate with rIVCFs is significantly higher than the self-reported complication rate with pIVCFs.

Perfusion reduction at transcatheter intraarterial perfusion MR imaging: a promising intraprocedural biomarker to predict transplant-free survival during chemoembolization of hepatocellular carcinoma

PURPOSE

To investigate the predictive value of transcatheter intraarterial perfusion (TRIP) magnetic resonance (MR) imaging-measured tumor perfusion changes during transarterial chemoembolization on transplant-free survival (TFS) in patients with unresectable hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This HIPAA-compliant prospective study was approved by the institutional review board. Written informed consent was obtained from all patients. Fifty-one consecutive adult patients with surgically unresectable single or multifocal measurable HCC and adequate laboratory parameters who underwent chemoembolization in a combined MR imaging-interventional radiology suite between February 2006 and June 2010 were studied. Tumor perfusion changes during chemoembolization were measured by using TRIP MR imaging with area under the time-signal intensity curve calculation. The end point of the study was TFS. The authors assessed the correlation between the percentage perfusion reduction in the tumor during chemoembolization and TFS by using univariate and multivariate analyses.

RESULTS

Fifty patients (mean age, 61 years; 39 men aged 42-87 years [mean age, 61 years] and 11 women aged 49-83 years [mean age, 62 years]) were eligible for the analysis. Patients with 35%-85% intraprocedural tumor area under the time-signal intensity curve reduction (n = 32) showed significantly improved median TFS compared with patients with an area under the time-signal intensity curve reduction outside this range (n = 18) (16.6 months [95% confidence interval: 11.2, 22.0 months] vs 9.3 months [95% confidence interval: 6.6, 12.0 months], respectively; P = .046; hazard ratio: 0.46; 95% confidence interval: 0.21, 1.00). The cumulative TFS rates in the 35%-85% and less than 35% or more than 85% perfusion reduction groups at 1, 2, and 5 years after chemoembolization were 66.4%, 42.2%, and 28.2% versus 33.8%, 16.9%, and 0%, respectively.

CONCLUSION

The study shows evidence of an association between intraprocedural tumor perfusion reduction during chemoembolization and TFS and suggests the utility of TRIP MR imaging- measured tumor perfusion reduction as an intraprocedural imaging biomarker during chemoembolization.

Optimizing the use of inferior vena cava filters in oncology patients: are all filters created equally?

Many studies have supported the efficacy of inferior vena cava filters (IVCF) in the setting of venous thromboembolic disease, particularly in oncologic patients who are at increased risk. The advent of retrievable IVCF designs has prompted dramatically expanded use for patients with widely accepted indications but also disproportionately so in patients with so-called extended indications. At the same time, an alarming increase in filter-related complications has been reported both in the literature and through regulatory agencies, leading to government agency-issued warnings. The synergistic effect of these two interconnected phenomena is explained through a careful review of the evolution of IVCF device design. Critical differences exist when comparing retrievable IVCF and permanent IVCF. IVCF utilization can be optimized by prospectively identifying which patients are best served by a specific IVCF device. Careful follow-up strategies are also needed to ensure that all IVCFs are removed as soon as they are no longer needed. Finally, adjunctive techniques for removing "difficult" filters help maximize the number of IVCF removed and minimize IVCF left implanted needlessly.

Radiation lobectomy: time-dependent analysis of future liver remnant volume in unresectable liver cancer as a bridge to resection

BACKGROUND & AIMS

Portal vein embolization (PVE) is a standard technique for patients not amenable to liver resection due to small future liver remnant ratio (FLR). Radiation lobectomy (RL) with (90)Y-loaded microspheres (Y90) is hypothesized to induce comparable volumetric changes in liver lobes, while potentially controlling the liver tumor and limiting tumor progression in the untreated lobe. We aimed at testing this concept by performing a comprehensive time-dependent analysis of liver volumes following radioembolization.

METHODS

83 patients with right unilobar disease with hepatocellular carcinoma (HCC; N=67), cholangiocarcinoma (CC; N=8) or colorectal cancer (CRC; N=8) were treated by Y90 RL. The total liver volume, lobar (parenchymal) and tumor volumes, FLR and percentage of FLR hypertrophy from baseline (%FLR hypertrophy) were assessed on pre- and post-Y90 CT/MRI scans in a dynamic fashion.

RESULTS

Right lobe atrophy (p=0.003), left lobe hypertrophy (p<0.001), and FLR hypertrophy (p<0.001) were observed 1 month after Y90 and this was consistent at all follow-up time points. Median %FLR hypertrophy reached 45% (5-186) after 9 months (p<0.001). The median maximal %FLR hypertrophy was 26% (-14 → 86). Portal vein thrombosis was correlated to %FLR hypertrophy (p=0.02). Median Child-Pugh score worsening (6 → 7) was seen at 1 to 3 months (p=0.03) and 3 to 6 months (p=0.05) after treatment. Five patients underwent successful right lobectomy (HCC N=3, CRC N=1, CC N=1) and 6 HCCs were transplanted.

CONCLUSIONS

Radiation lobectomy by Y90 is a safe and effective technique to hypertrophy the FLR. Volumetric changes are comparable (albeit slightly slower) to PVE while the right lobe tumor is treated synchronously. This novel technique is of particular interest in the bridge-to-resection setting.

Image-guided local delivery strategies enhance therapeutic nanoparticle uptake in solid tumors

Nanoparticles (NP) have emerged as a novel class of therapeutic agents that overcome many of the limitations of current cancer chemotherapeutics. However, a major challenge to many current NP platforms is unfavorable biodistribution, and limited tumor uptake, upon systemic delivery. Delivery, therefore, remains a critical barrier to widespread clinical adoption of NP therapeutics. To overcome these limitations, we have adapted the techniques of image-guided local drug delivery to develop nanoablation and nanoembolization. Nanoablation is a tumor ablative strategy that employs image-guided placement of electrodes into tumor tissue to electroporate tumor cells, resulting in a rapid influx of NPs that is not dependent on cellular uptake machinery or stage of the cell cycle. Nanoembolization involves the image-guided delivery of NPs and embolic agents directly into the blood supply of tumors. We describe the design and testing of our innovative local delivery strategies using doxorubicin-functionalized superparamagnetic iron oxide nanoparticles (DOX-SPIOs) in cell culture, and the N1S1 hepatoma and VX2 tumor models, imaged by high resolution 7T MRI. We demonstrate that local delivery techniques result in significantly increased intratumoral DOX-SPIO uptake, with limited off-target delivery in tumor-bearing animal models. The techniques described are versatile enough to be extended to any NP platform, targeting any solid organ malignancy that can be accessed via imaging guidance.

Cancer concepts and principles: primer for the interventional oncologist-part II

This is the second of a two-part overview of the fundamentals of oncology for interventional radiologists. The first part focused on clinical trials, basic statistics, assessment of response, and overall concepts in oncology. This second part aims to review the methods of tumor characterization; principles of the oncology specialties, including medical, surgical, radiation, and interventional oncology; and current treatment paradigms for the most common cancers encountered in interventional oncology, along with the levels of evidence that guide these treatments.

Cancer concepts and principles: primer for the interventional oncologist-part I

A sophisticated understanding of the rapidly changing field of oncology, including a broad knowledge of oncologic disease and the therapies available to treat them, is fundamental to the interventional radiologist providing oncologic therapies, and is necessary to affirm interventional oncology as one of the four pillars of cancer care alongside medical, surgical, and radiation oncology. The first part of this review intends to provide a concise overview of the fundamentals of oncologic clinical trials, including trial design, methods to assess therapeutic response, common statistical analyses, and the levels of evidence provided by clinical trials.

Yttrium-90 radioembolization for intrahepatic cholangiocarcinoma: safety, response, and survival analysis

PURPOSE

To present data on safety, antitumoral response, and survival following yttrium-90 ((90)Y) radioembolization for patients with unresectable intrahepatic cholangiocarcinoma (ICC).

MATERIALS AND METHODS

The present study expands on the cohort of 24 patients with ICC described in a pilot study, and includes 46 patients treated with (90)Y radioembolization at a single institution during an 8-year period. Via retrospective review of a prospectively collected database, patients were stratified by performance status, tumor distribution (solitary or multifocal), tumor morphology (infiltrative or peripheral), and presence/absence of portal vein thrombosis. Primary endpoints included biochemical and clinical toxicities, and secondary endpoints included imaging response (World Health Organization [WHO] and European Association for the Study of Liver Disease [EASL] criteria) and survival. Uni-/multivariate analyses were performed.

RESULTS

Ninety-two treatments were performed, with a mean of two per patient. Fatigue and transient abdominal pain occurred in 25 patients (54%) and 13 patients (28%), respectively. Treatment-related gastroduodenal ulcer developed in one patient (2%). WHO imaging findings included partial response (n = 11; 25%), stable disease (n = 33; 73%), and progressive disease (n = 1; 2%). EASL imaging findings included partial/complete response (n = 33; 73%) and stable disease (n = 12; 27%). Survival varied based on presence of multifocal (5.7 mo vs 14.6 mo), infiltrative (6.1 mo vs 15.6 mo), and bilobar disease (10.9 mo vs 11.7 mo). Disease was converted to resectable status in five patients, who successfully underwent curative (ie, R0) resection.

CONCLUSIONS

Radioembolization with (90)Y is safe and demonstrates antitumoral response and survival benefit in select patients with ICC. Results are most pronounced in patients with solitary tumors, for whom conversion to curative resection is possible.

Hepatic radioembolization complicated by fulminant hepatic failure

A 68-year-old man with a history of metastatic colorectal carcinoma underwent left hepatic lobectomy and right hepatic wedge resection as initial treatment of his metastatic disease. He subsequently underwent right lobar radioembolization for treatment of a segment 8 lesion. At 6 weeks postembolization, he developed hepatic dysfunction which rapidly progressed to fulminant liver failure. A liver biopsy revealed hepatic venous obstruction and fibrosis. The patient died 14 weeks after radioembolization.

Hepatic radioembolization complicated by abscess

Hepatic abscess is a rare complication of yttrium-90 radioembolization of hepatic tumors that most commonly occurs in patients with a history of biliary intervention. Patients usually present several weeks after therapy with pain, nausea, vomiting, and fever. Cross-sectional imaging is necessary in cases of suspected abscess to ensure prompt diagnosis and to help plan treatment, which involves antibiotics and percutaneous drainage.

Endovascular stent reconstruction of the inferior vena cava complicated by duodenocaval fistula

A patient with retroperitoneal metastatic uterine adenocarcinoma resulting in symptomatic occlusion of the inferior vena cava underwent palliative endovascular stent reconstruction and subsequent radiation therapy. She then developed sepsis and massive lower gastrointestinal bleeding. Computed tomography (CT) and cavography demonstrated a fistulous communication between the duodenum and the stented segment of inferior vena cava. Deployment of endovascular stent graft devices successfully occluded the fistulous communication and resulted in clinical improvement.

Alpha-fetoprotein response correlates with EASL response and survival in solitary hepatocellular carcinoma treated with transarterial therapies: a subgroup analysis

BACKGROUND & AIMS

Alpha-fetoprotein (AFP) is a universally recognized tumor marker in hepatocellular carcinoma (HCC). Its utility in assessing response to treatment remains controversial. We sought to study the: (a) correlation between AFP response and imaging response, and (b) ability of AFP, EASL, and WHO response to predict survival outcomes in patients with solitary HCC.

METHODS

Six hundred and twenty-nine HCC patients were treated with transarterial locoregional therapies over an 11-year period. To eliminate confounding factors, we included patients with single tumors, baseline AFP ≥200ng/ml, and no extrahepatic disease; this identified our study cohort of 51 patients. AFP response was defined as>50% decrease from baseline; this was correlated to EASL and WHO response criteria by Kappa agreement, Pearson correlation and receiver operating curves. Survival analyses were performed by Landmark, risk-of-death and Mantel-Byar methodologies. None of the patients received sorafenib.

RESULTS

Three months post-treatment, AFP and EASL response correlated well (Kappa: 0.83; Pearson: 0.84); the sensitivity, specificity, positive and negative predictive values of AFP in predicting EASL response at 3 months were 96.6%, 85.7%, 92.3%, and 93.3%, respectively. Correlation with WHO response was low. From the 3-month landmark, WHO, EASL, and AFP responders survived longer than non-responders (p=0.006, 0.0001, and <0.0001, respectively). The risk of death was lower for EASL and AFP responders by both risk-of-death and Mantel-Byar methodologies (p <0.05).

CONCLUSIONS

Response by AFP and EASL are predictors of survival outcome in patients with solitary HCC. AFP correlates with imaging response assessment by EASL guidelines. Achieving AFP response should be one of the therapeutic intents of locoregional therapies (LRTs).

Treating and downstaging hepatocellular carcinoma in the caudate lobe with yttrium-90 radioembolization

PURPOSE

This study was designed to determine the technical feasibility, safety, efficacy, and potential to downstage patients to within transplantation criteria when treating patients with hepatocellular carcinoma (HCC) of the caudate lobe using Y90 radioembolization.

METHODS

During a 4-year period, 8 of 291 patients treated with radioembolization for unresectable HCC had disease involving the caudate lobe. All patients were followed for treatment-related clinical/biochemical toxicities, serum tumor marker response, and treatment response. Imaging response was assessed with the World Health Organization (WHO) and European Association for the Study of the Liver (EASL) classification schemes. Pathologic response was reported as percent necrosis at explantation.

RESULTS

Caudate lobe radioembolization was successfully performed in all eight patients. All patients presented with both cirrhosis and portal hypertension. Half were United Network for Organ Sharing (UNOS) stage T3 (n = 4, 50%). Fatigue was reported in half of the patients (n = 4, 50%). One (13%) grade 3/4 bilirubin toxicity was reported. One patient (13%) showed complete tumor response by WHO criteria, and three patients (38%) showed complete response using EASL guidelines. Serum AFP decreased by more than 50% in most patients (n = 6, 75%). Four patients (50%) were UNOS downstaged from T3 to T2, three of who underwent transplantation. One specimen showed histopathologic evidence of 100% complete necrosis, and two specimens demonstrated greater than 50% necrosis.

CONCLUSIONS

Radioembolization with yttrium-90 appears to be a feasible, safe, and effective treatment option for patients with unresectable caudate lobe HCC. It has the potential to downstage patients to transplantation.