Supply Costs in Complex and Routine Inferior Vena Cava Filter Retrieval: 10 Years' Data from a Single Center

PURPOSE

To characterize the medical supply costs associated with inferior vena cava filter retrieval (IVCFR) using endobronchial forceps (EFs), a snare, or Recovery Cone (RC).

MATERIALS AND METHODS

In total, 594 of 845 IVCFRs attempted at a tertiary referral hospital between October 1, 2012, and June 20, 2022 were categorized by intended retrieval strategy informed by, rotational cavography as follows: (a) EF (n = 312) for tilted or tip-embedded/strut-embedded filters and for long-dwelling closed-cell filters and (b) a snare (n = 255) or (c) RC (n = 27) for other well-positioned filters with or mostly without hooks, respectively. List prices of relevant supplies at time of retrieval were obtained or, rarely, estimated using a standard procedure. Contrast use, fluoroscopic time, filter type, dwell time, and patient age and sex were recorded. Mean between-group cost differences were estimated by linear regression, adjusting for date. Additional models evaluated filter type, dwell time, and patient-level effects.

RESULTS

Of the 594 IVCFRs, 591 were successful, whereas 2 EF and 1 snare retrievals failed. Moreover, 4 EF retrievals were successful with a snare and 2 with smaller EF, 12 snare retrievals were successful with EF, 1 RC retrieval was successful with a snare and 2 with EF. Principal model indicated a significantly lower mean cost of EF ($564.70, SE ± 9.75) than that of snare ($811.29, SE ± 10.83; P < .0001) and RC ($1,465.48, SE ± 47.12; P < .0001) retrievals. Adjusted models yielded consistent results. Had all retrievals been attempted with EF, estimated undiscounted full-period supplies savings would be $87,201.51.

CONCLUSIONS

EFs are affordable for complex IVCFR, and extending their use to routine IVCFR could lead to considerable cost savings.

Grasp-and-Fold Technique for Complex Inferior Vena Cava Filter Retrieval

This study evaluated the use of the grasp-and-fold technique for complex forceps retrieval of inferior vena cava (IVC) filters. A retrospective study of 14 patients (12 women and 2 men) who had either deeply tip-embedded or severely distorted IVC filters was performed at a single institution over 10 years. In this technique, endobronchial forceps were used to fold the filter in half to remove it through the sheath because the filter tip could not be accessed by dissection. The grasp-and-fold technique successfully removed all 14 filters. One patient had retained filter struts, which were present before the procedure. One mild and 5 moderate adverse events (AEs), including fracture fragment embolization requiring retrieval and self-limited IVC extravasation, occurred. No severe AEs occurred. In this small patient cohort, the grasp-and-fold forceps technique successfully retrieved deeply tip-embedded or distorted IVC filters with inaccessible tips.

Endobronchial Forceps Retrieval of Embedded Inferior Vena Cava Filters: Retrieval of 535 Filters at a Single Center

PURPOSE

To report results of 16 years of using the endobronchial forceps technique to remove embedded inferior vena cava (IVC) filters.

MATERIALS AND METHODS

Between January 2005 and June 2021, 534 patients (310 women and 224 men) with a mean age of 52 years (standard deviation [SD] ± 16 years) presented for complex filter retrieval of 535 tip- or strut-embedded IVC filters. Tip-embedded filters were diagnosed on rotational venography. Filters were considered strut-embedded if they were closed-cell filters with dwell times of >6 months. The filter was dissected from the IVC using rigid bronchoscopy forceps and removed through a vascular sheath.

RESULTS

The endobronchial forceps technique was successful in 530 of 537 retrieval attempts on an intention-to-treat basis (98.7%); a total of 530 filters were retrieved. There were 7 failures: (a) 5 failed retrieval attempts (2 that were retrieved successfully in subsequent procedures) and (b) 2 for which retrieval was not attempted. The mean filter dwell time was 1,459 days (SD ± 1,617 days). Laser sheaths were not used for any removal. Filters included herein were 137 Celect (94 Celect and 43 Celect Platinum), 99 Günther Tulip, 72 Option (48 Option and 24 Option Elite), 68 G2, 45 G2X/Eclipse, 42 Denali, 30 OptEase, 29 Recovery, 7 Meridian, and 6 ALN with Hook filters. Thirty-four minor (6.3%) and 11 major (2%) adverse events (AEs) occurred, which did not result in permanent sequelae.

CONCLUSIONS

Use of endobronchial forceps for removal of tip- and strut-embedded retrievable IVC filters is effective and has low AE rates.

Transjugular intrahepatic portosystemic shunt for the management of symptomatic malignant pseudocirrhosis

BACKGROUND

Pseudocirrhosis is defined by radiologic changes of the liver parenchyma secondary to metastatic disease and/or cancer treatments, and portends a high rate of morbidity and mortality from sequelae of portal hypertension. Transjugular intrahepatic portosystemic shunt (TIPS) is an effective treatment for portal hypertension; however, TIPS is relatively contraindicated in the setting of hepatic metastases. The study aims to determine the technical efficacy and clinical outcomes of patients undergoing TIPS for symptomatic pseudocirrhosis.

METHODS

Retrospective analysis of patients with hepatic malignancy who underwent TIPS between 2008 and 2020 at a single tertiary care center. Patients with imaging findings of pseudocirrhosis and without history of primary liver malignancy or confounding causes of cirrhosis were included. West Haven scores assessing hepatic encephalopathy were obtained from chart review. Technical success was defined as successful TIPS creation with reduction in the portosystemic gradient (PSG). Clinical success was defined as resolution of variceal bleeding and/or ascites.

RESULTS

Nine patients (4 female/5 male), average (± SD) age 61.2±9.5 years with metastatic pseudocirrhosis were included for analysis. Primary malignancy was colorectal adenocarcinoma (n=5), neuroendocrine tumor (n=3), and malignant endothelial hemangioendothelioma (n=1). Average Model for End Stage Liver Disease (MELD-Na) score was 15.7±3.7. Technical success was 8/9 (89%) with average PSG reduced from 23.5±11.0 to 6.5±2.8 mmHg (P=0.001). Clinical success was 6/9 (67%). Two patients required TIPS revision after initial clinical success. Mild-moderate HE occurred in 6/9 patients post TIPS (67%), with a highest West Haven score of 2. Time from TIPS to death for acute variceal bleeding and ascites was 4.9±4.2 and 12±16.5 months, respectively. Cause of death was disease progression (n=5), variceal bleeding (n=1), or unavailable (n=2).

CONCLUSIONS

TIPS in the setting of malignant pseudocirrhosis can be created safely with similar clinical outcomes to TIPS performed for benign disease. Rates of low-grade hepatic encephalopathy may be higher amongst patients undergoing TIPS for pseudocirrhosis.

Variability in biopsy quality informs translational research applications in hepatocellular carcinoma

In the era of precision medicine, biopsies are playing an increasingly central role in cancer research and treatment paradigms; however, patient outcomes and analyses of biopsy quality, as well as impact on downstream clinical and research applications, remain underreported. Herein, we report biopsy safety and quality outcomes for percutaneous core biopsies of hepatocellular carcinoma (HCC) performed as part of a prospective clinical trial. Patients with a clinical diagnosis of HCC were enrolled in a prospective cohort study for the genetic, proteomic, and metabolomic profiling of HCC at two academic medical centers from April 2016 to July 2020. Under image guidance, 18G core biopsies were obtained using coaxial technique at the time of locoregional therapy. The primary outcome was biopsy quality, defined as tumor fraction in the core biopsy. 56 HCC lesions from 50 patients underwent 60 biopsy events with a median of 8 core biopsies per procedure (interquartile range, IQR, 7–10). Malignancy was identified in 45/56 (80.4%, 4 without pathology) biopsy events, including HCC (40/56, 71.4%) and cholangiocarcinoma (CCA) or combined HCC-CCA (5/56, 8.9%). Biopsy quality was highly variable with a median of 40% tumor in each biopsy core (IQR 10–75). Only 43/56 (76.8%) and 23/56 (41.1%) samples met quality thresholds for genomic or metabolomic/proteomic profiling, respectively, requiring expansion of the clinical trial. Overall and major complication rates were 5/60 (8.3%) and 3/60 (5.0%), respectively. Despite uniform biopsy protocol, biopsy quality varied widely with up to 59% of samples to be inadequate for intended purpose. This finding has important consequences for clinical trial design and highlights the need for quality control prior to applications in which the presence of benign cell types may substantially alter findings.

Stability of Retained Inferior Vena Cava Filter Fragments After Filter Removal

PURPOSE

To assess the stability and outcome of fractured inferior vena cava (IVC) filter fragments that are retained in patients after IVC filter removal.

MATERIALS AND METHODS

A retrospective analysis was conducted on all patients at a single tertiary referral center between May 2005 and June 2020 with fractured IVC filters where fragment(s) were retained after removal of the main filter body. IVC filter fragment stability was assessed by a clinician review of computed tomography images, chosen from available radiologic studies, to best visualize the fragments. Data collected included filter type, fragment location, duration of fragment follow-up, fragment stability in location, and further fragment fracture or clinical sequelae.

RESULTS

Seventy-seven patients with retained IVC filter fragment(s) after complex filter removal were identified. Of this, 37 patients (14 men, 23 women) were deemed to have adequate imaging follow-up to assess positional stability of the retained fragments, whereas the remainder were excluded from further analysis. Excluding fractured foot processes, 51 separate filter fragments were retrospectively identified and followed for a median duration of 726 days (interquartile range, 843 days; range, 28-3353 days). Filter designs producing the studied fragments included Celect, G2, Recovery, Günther, OptEase, Meridian, and G2X/Eclipse. In all, 50 of 51 (98%) fragments were found to be unchanged in position during their respective intervals of observation. One fragment displayed a rotational change without migrating from its original location. No further fragment fractures or clinical sequelae were observed among the group.

CONCLUSIONS

When asymptomatic, retained IVC filter fragments are predominantly stable and can be safely followed on an intermediate-term basis.

Preoperative prediction of the stage, size, grade, and necrosis score in clear cell renal cell carcinoma using MRI-based radiomics

PURPOSE

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma. Currently, there is a lack of noninvasive methods to stratify ccRCC prognosis prior to any invasive therapies. The purpose of this study was to preoperatively predict the tumor stage, size, grade, and necrosis (SSIGN) score of ccRCC using MRI-based radiomics.

METHODS

A multicenter cohort of 364 histopathologically confirmed ccRCC patients (272 low [< 4] and 92 high [≥ 4] SSIGN score) with preoperative T2-weighted and T1-contrast-enhanced MRI were retrospectively identified and divided into training (254 patients) and testing sets (110 patients). The performance of a manually optimized radiomics model was assessed by measuring accuracy, sensitivity, specificity, area under receiver operating characteristic curve (AUROC), and area under precision-recall curve (AUPRC) on an independent test set, which was not included in model training. Lastly, its performance was compared to that of a machine learning pipeline, Tree-Based Pipeline Optimization Tool (TPOT).

RESULTS

The manually optimized radiomics model using Random Forest classification and Analysis of Variance feature selection methods achieved an AUROC of 0.89, AUPRC of 0.81, accuracy of 0.89 (95% CI 0.816-0.937), specificity of 0.95 (95% CI 0.875-0.984), and sensitivity of 0.72 (95% CI 0.537-0.852) on the test set. The TPOT using Extra Trees Classifier achieved an AUROC of 0.94, AUPRC of 0.83, accuracy of 0.89 (95% CI 0.816-0.937), specificity of 0.95 (95% CI 0.875-0.984), and sensitivity of 0.72 (95% CI 0.537-0.852) on the test set.

CONCLUSION

Preoperative MR radiomics can accurately predict SSIGN score of ccRCC, suggesting its promise as a prognostic tool that can be used in conjunction with diagnostic markers.

Infection Rates Following Hepatic Embolotherapy in Patients with Prior Biliary Interventions: Comparison of Single-Drug Moxifloxacin and Multidrug Antibiotic Prophylaxis

PURPOSE

To investigate the incidence of infection in patients with prior biliary interventions undergoing hepatic embolotherapy following extended antibiotic prophylaxis using moxifloxacin monotherapy or a multidrug regimen.

MATERIAL AND METHODS

Under an Institutional Review Board-approved protocol, retrospective review of a quality assurance database identified all liver-directed therapies (LDTs) at a tertiary care center between 2010 and 2019 with biliary intervention prior to LDT Records were reviewed for infectious complications within 3 months of chemo- or radioembolization. Patients were categorized based on extended antibiotic prophylaxis regimen: oral moxifloxacin monotherapy or multidrug regimen of levofloxacin and metroniodazole plus preprocedural neomycin and erythromycin. Procedures without at least 2 months of clinical follow-up, hepatic ablation, and procedures without extended antibiotic prophylaxis were excluded Regression analysis was used to analyze multivariate data to detect a difference in infection rate.

RESULTS

Twenty-four chemoembolization and 58 radioembolization procedures were performed on 55 patients with prior biliary interventions. Forty-four used monotherapy and 38 used multidrug regimen. The incidence of infection was 16.7% (4/24) after chemoembolization and 13.8% (8/58) after radioembolization The incidence of infection in patients did not differ between antibiotic prophylaxis regimens (18.2% [8/44] with moxifloxacin monotherapy and 10.5% [4/38] multidrug regimen, P = .3) or between types of biliary interventions (24.1% [7/29] with bilioenteric anastomosis and 23.8% [5/21] biliary stenting, P = .3).

CONCLUSIONS

The types of extended antibiotic prophylaxis (moxifloxacin monotherapy vs multitherapy), prior biliary intervention, and embolotherapy were not found to be associated with differences in the incidence of infectious complications in this population.

Abstract PD9-10: Investigating the clinical utility of tumor mutational burden in predicting rapid progression and death in patients with metastatic breast cancer

Background Up to 30% of breast cancer patients will eventually relapse with metastatic disease. With an increasing array of therapeutic options, there is an ongoing need for predictive biomarkers to help guide treatment strategies including sequencing of therapies in the metastatic setting. We sought to evaluate the prognostic and predictive potential of a panel-specific tumor mutational burden (TMB) in metastatic breast cancer patients.

Methods METAMORPH is a prospective, longitudinal cohort study. Eligible patients (pts) had newly diagnosed or progressive metastatic breast cancer and enrolled prior to starting a new line of therapy (physician’s choice) at the University of Pennsylvania. Pts underwent tissue biopsy of a suspected metastatic site. Tumor samples were analyzed for mutations and copy number alterations (CNA’s) using our institution’s CLIA-certified Center for Personalized Diagnostics (CPD) targeted gene panel, which evolved over the course of the study from 20 genes to 152 genes. TMB-high (TMB-H) was defined as ≥3 mutations and/or copy-number gains (CNG) among 18 genes shared across all panel versions. Pts were followed for time to progression (TTP), progression-free survival (PFS), and overall survival (OS). The frequency of rapid progressors and rapid death (defined as having progressed or died within 3 months of enrollment, respectively) was assessed.

Results Three hundred pts enrolled from 2013-2020, of whom 200 pts had CPD reports generated. Of these, 12 pts were excluded due to either no treatment change on enrollment (n=11) or different primary cancer on biopsy (n=1). Thus 188 pts were included in this analysis. The median age was 55 years (range 28-79). 77% of pts identified as white, 18% as Black or African American, and 3.2% as Asian. Pts had a median of 1 line (range 0-12) of prior systemic therapy in the metastatic setting. 46.8% had no prior therapies for MBC, while 31% had ≥3 prior lines of therapy. 74.4% were HR+, 22.8% TNBC, and 2.7% HR-/HER2+. 6.9% of the cohort were classified as TMB-H. The average mutation/CNG rate was 2.2/sample, and 22.5% had no mutations or CNA’s. The most common mutations were TP53 (35%) and PIK3CA (26%).

While TMB-H patients showed a statistically non-significant trend towards shorter median TTP and PFS compared with TMB-L, they comprised a significantly greater proportion of rapid progressors (54.5% vs 24.1%, p=0.027), with an odds ratio for rapid progression of 3.8 (95% CI 1.08-13.2). In a multivariate logistic regression analysis, TMB-H remained independently associated with rapid progression when adjusted for receptor subtype and next line of therapy. Receptor subtype analysis revealed that ER- (including ER-/PR+) patients with TMB-H had a shorter median TTP compared to ER- TMB-L (147 vs 68 days, p=0.03). TMB-H was also associated with significantly shorter OS compared with TMB-L (587 vs 648 days, p=0.02; HR 2.2 [95% CI 1.11-4.41]). 44.4% of TMB-H pts died within 3 months of enrollment, as compared to 11.0% of TMB-L pts (p=0.005), with an odds ratio for rapid death, adjusted for number of previous lines of therapy and receptor subtype, of 6.7 (95% CI 1.5-31.0).

Conclusion MBC pts who are TMB-H represent a population who are highly resistant to standard therapies, progress rapidly, and have significantly shorter overall survival with more rapid time to death. Our data support further studies investigating the utility of TMB as a predictive biomarker in directing patients away from standard treatment options and towards novel approaches e.g. immunotherapy.

Citation Format: Igor Makhlin, Amy S Clark, Paul Wileyto, Noah Goodman, John Ndicu, Shannon DeLuca, Candace Clark, S. William Stavropoulos, Natalie Shih, Michael D Feldman, Susan M Domchek, Jennifer M Matro, Payal D Shah, Hayley M Knollman, Kevin R Fox, Kara N Maxwell, Lewis A Chodosh, Angela DeMichele. Investigating the clinical utility of tumor mutational burden in predicting rapid progression and death in patients with metastatic breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD9-10.

Prevalence and Characterization of Interaction of Retrievable Inferior Vena Cava Filters with the Spine in Patients Undergoing Complex Filter Removal

PURPOSE

To examine spinal interaction types and prevalence of inferior vena cava (IVC) filters in patients presenting for complex filter removal.

MATERIALS AND METHODS

The records of 447 patients presenting for complex removal of IVC filters were reviewed, including patient demographics, IVC filter dwell time, filter fracture status, and computed tomography (CT) evidence of filter interaction with the spine. Spinal interaction was defined as a filter strut touching or penetrating into the vertebral body or disc. Patients with evidence of filter penetration and spinal interaction had abdominal CT that preceded filter removal assessed by 2 interventional radiologists to categorize the type of spinal interaction, including bony reaction and osteophyte formation.

RESULTS

CT evidence of spinal interaction by the filter was found in 18% of patients (80/447). Interaction with the spine was more common in single point of fixation filters than filters with rails (P = .007) and was more likely in filters with round wires than flat wires (P = .0007). Patients with interaction had longer dwell times (mean [SD] 5.7 [4.46] y) compared with patients without interaction (mean [SD] 3.2 [3.85] y); this relationship was significant (P < .0001). Women were more likely than men to experience filter/spine interaction (P = .04). Filters with spinal interaction were more likely to be fractured (P = .001). Filter interaction was found in 38% (30/78) of patients with symptoms, including chest and back pain, compared with 14% (50/369) of patients without symptoms (P < .0001, odds ratio 3.99).

CONCLUSIONS

Retrievable IVC filters may interact with the spine. These interactions are associated with longer filter dwell times, female sex, and round wire filter construction.

Type 2 Endoleak Management

Type 2 endoleaks are the most common endoleak type following endovascular aneurysm repair. The natural history of these endoleaks can vary, with some demonstrating a self-limited or indolent course, while others can contribute to aneurysm sac enlargement and rupture. A variety of embolization techniques, including transarterial catheterization and direct sac puncture techniques, have been developed for the treatment of type 2 endoleaks. In this article, the authors review the indications, techniques, and outcomes of current treatment strategies for type 2 endoleaks.

Genomic landscape of metastatic breast cancer identifies preferentially dysregulated pathways and targets

Nearly all breast cancer deaths result from metastatic disease. Despite this, the genomic events that drive metastatic recurrence are poorly understood. We performed whole-exome and shallow whole-genome sequencing to identify genes and pathways preferentially mutated or copy-number altered in metastases compared with the paired primary tumors from which they arose. Seven genes were preferentially mutated in metastases - MYLK, PEAK1, SLC2A4RG, EVC2, XIRP2, PALB2, and ESR1 - 5 of which are not significantly mutated in any type of human primary cancer. Four regions were preferentially copy-number altered: loss of STK11 and CDKN2A/B, as well as gain of PTK6 and the membrane-bound progesterone receptor, PAQR8. PAQR8 gain was mutually exclusive with mutations in the nuclear estrogen and progesterone receptors, suggesting a role in treatment resistance. Several pathways were preferentially mutated or altered in metastases, including mTOR, CDK/RB, cAMP/PKA, WNT, HKMT, and focal adhesion. Immunohistochemical analyses revealed that metastases preferentially inactivate pRB, upregulate the mTORC1 and WNT signaling pathways, and exhibit nuclear localization of activated PKA. Our findings identify multiple therapeutic targets in metastatic recurrence that are not significantly mutated in primary cancers, implicate membrane progesterone signaling and nuclear PKA in metastatic recurrence, and provide genomic bases for the efficacy of mTORC1, CDK4/6, and PARP inhibitors in metastatic breast cancer.

Diagnosis and Treatment of Nonmaturing Fistulae for Hemodialysis Access via Transradial Approach: A Case-Control Study

PURPOSE

To compare outcomes of transradial access for endovascular treatment of nonmaturing hemodialysis fistulae compared to brachial arteriography followed by unidirectional or bidirectional fistula access for intervention.

MATERIALS AND METHODS

In this institutional review board-approved, retrospective, case-control study, 56 consecutive patients with nonmaturing arteriovenous fistulae underwent percutaneous intervention between 2015 and 2018. The transradial group (n = 28) underwent radial artery access for diagnostic fistulography and intervention. The control group (n = 28) underwent retrograde brachial artery access for fistulography followed by unidirectional/bidirectional fistula access for intervention. Both groups had similar demographics, fistula characteristics, and stenosis locations.

RESULTS

Fewer punctures were required in the transradial group compared to controls (1.2 vs 2.4, P < .0001), and procedure time was shorter (64.9 vs 91.3 minutes, P = .0016). Anatomic, technical, and clinical success rates trended higher in the transradial group compared to controls (93% vs 86%, 96% vs 89%, and 82% vs 64%, respectively). Nonmaturation resulting in fistula abandonment was lower in the transradial group (3.7% vs 25%, P = .025). Primary unassisted patency at 3, 6, and 12 months was 77.1% ± 8.2%, 73.1% ± 8.7%, and 53.3% ± 10.6% in the transradial group, respectively, and 63.0% ± 9.3%, 55.6% ± 9.6%, and 48.1% ± 9.6% in the control group, respectively (P = .76). Primary assisted patency at 12 months was 92.3% ± 5.3% in the transradial group compared to 61.8% ± 9.6% at 12 months in the control group (P = .021). No major complications occurred. Minor complications were lower in the transradial group than in the control group (14% vs 39%, P = .068).

CONCLUSIONS

Treatment of nonmaturing fistulae via a transradial approach was safe, improved midterm patency, and was associated with lower rates of fistula abandonment.

Deep Learning Based on MRI for Differentiation of Low- and High-Grade in Low-Stage Renal Cell Carcinoma

Pretreatment determination of renal cell carcinoma aggressiveness may help to guide clinical decision-making.

PURPOSE

To evaluate the efficacy of residual convolutional neural network using routine MRI in differentiating low-grade (grade I-II) from high-grade (grade III-IV) in stage I and II renal cell carcinoma.

STUDY TYPE

Retrospective.

POPULATION

In all, 376 patients with 430 renal cell carcinoma lesions from 2008-2019 in a multicenter cohort were acquired. The 353 Fuhrman-graded renal cell carcinomas were divided into a training, validation, and test set with a 7:2:1 split. The 77 WHO/ISUP graded renal cell carcinomas were used as a separate WHO/ISUP test set.

FIELD STRENGTH/SEQUENCE

1.5T and 3.0T/T₂ -weighted and T₁ contrast-enhanced sequences.

ASSESSMENT

The accuracy, sensitivity, and specificity of the final model were assessed. The receiver operating characteristic (ROC) curve and precision-recall curve were plotted to measure the performance of the binary classifier. A confusion matrix was drawn to show the true positive, true negative, false positive, and false negative of the model.

STATISTICAL TESTS

Mann-Whitney U-test for continuous data and the chi-square test or Fisher's exact test for categorical data were used to compare the difference of clinicopathologic characteristics between the low- and high-grade groups. The adjusted Wald method was used to calculate the 95% confidence interval (CI) of accuracy, sensitivity, and specificity.

RESULTS

The final deep-learning model achieved a test accuracy of 0.88 (95% CI: 0.73-0.96), sensitivity of 0.89 (95% CI: 0.74-0.96), and specificity of 0.88 (95% CI: 0.73-0.96) in the Fuhrman test set and a test accuracy of 0.83 (95% CI: 0.73-0.90), sensitivity of 0.92 (95% CI: 0.84-0.97), and specificity of 0.78 (95% CI: 0.68-0.86) in the WHO/ISUP test set.

DATA CONCLUSION

Deep learning can noninvasively predict the histological grade of stage I and II renal cell carcinoma using conventional MRI in a multiinstitutional dataset with high accuracy.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 2.

Deep Learning to Distinguish Benign from Malignant Renal Lesions Based on Routine MR Imaging

PURPOSE

With increasing incidence of renal mass, it is important to make a pretreatment differentiation between benign renal mass and malignant tumor. We aimed to develop a deep learning model that distinguishes benign renal tumors from renal cell carcinoma (RCC) by applying a residual convolutional neural network (ResNet) on routine MR imaging.

EXPERIMENTAL DESIGN

Preoperative MR images (T2-weighted and T1-postcontrast sequences) of 1,162 renal lesions definitely diagnosed on pathology or imaging in a multicenter cohort were divided into training, validation, and test sets (70:20:10 split). An ensemble model based on ResNet was built combining clinical variables and T1C and T2WI MR images using a bagging classifier to predict renal tumor pathology. Final model performance was compared with expert interpretation and the most optimized radiomics model.

RESULTS

Among the 1,162 renal lesions, 655 were malignant and 507 were benign. Compared with a baseline zero rule algorithm, the ensemble deep learning model had a statistically significant higher test accuracy (0.70 vs. 0.56, P = 0.004). Compared with all experts averaged, the ensemble deep learning model had higher test accuracy (0.70 vs. 0.60, P = 0.053), sensitivity (0.92 vs. 0.80, P = 0.017), and specificity (0.41 vs. 0.35, P = 0.450). Compared with the radiomics model, the ensemble deep learning model had higher test accuracy (0.70 vs. 0.62, P = 0.081), sensitivity (0.92 vs. 0.79, P = 0.012), and specificity (0.41 vs. 0.39, P = 0.770).

CONCLUSIONS

Deep learning can noninvasively distinguish benign renal tumors from RCC using conventional MR imaging in a multi-institutional dataset with good accuracy, sensitivity, and specificity comparable with experts and radiomics.

Magnification Spot Radiographs Improve Assessment for Inferior Vena Cava Filter Fractures prior to Removal Compared to CT

PURPOSE

To determine if magnification spot radiographs acquired before attempting inferior vena cava (IVC) filter removal have value in the assessment for filter fractures.

MATERIALS AND METHODS

A retrospective review of complex IVC filter removals performed at a tertiary referral center from October 2015 to May 2017 was performed. Magnification spot radiographs (frontal and at least 2 oblique views) were obtained with the fluoroscopic unit in the procedure suite prior to venous access for filter removal. Patients were included in the study if a computed tomography (CT) scan of the abdomen/pelvis before filter removal was available. Ninety-six patients (47 women and 49 men) were included. Most removed filters were the Recovery/G2/G2X/Eclipse/Meridian (n = 28), the Günther Tulip (n = 26), and the Celect/Celect Platinum (n = 22). Blinded review of the pre-procedural CT scans and spot radiographs for the presence of filter fractures was performed by 2 interventional radiologists. Accuracy of each modality was assessed using the status of the explanted filter as the gold standard. Agreement between the 2 readers was assessed with the kappa statistic.

RESULTS

Fractures were present in 27 explanted filters (28%). Accuracy of CT was 88% and 68% for readers 1 and 2, respectively, which increased to 98% and 97% with magnification spot radiographs. The kappa statistic was 0.12 for CT and 0.97 for spot radiographs.

CONCLUSIONS

Magnification spot radiographs acquired before attempting IVC filter removal improve detection of filter fractures and agreement among interventional radiologists. Therefore, these should be performed routinely to allow for optimal treatment planning.

A Comparison of Cryoablation with Heat-Based Thermal Ablation for Treatment of Clinical T1a Renal Cell Carcinoma: A National Cancer Database Study

PURPOSE

To compare the overall survival (OS) of patients receiving cryoablation versus heat-based thermal ablation for clinical T1a renal cell carcinoma (RCC) in a large national cohort.

MATERIALS AND METHODS

Patients with RCC from 2004 to 2014 who were treated with ablation were identified from the National Cancer Database. OS was estimated with the use of the Kaplan-Meier method and evaluated by means of log-rank test, univariate and multivariate Cox proportional hazard regression, and propensity score-matched analysis.

RESULTS

A total of 3,936 patients who received cryoablation and 2,322 who received heat-based thermal ablation met the inclusion criteria. The mean age was 67 ± 12 year, and the mean size of tumors was 25 ± 8 mm. The 3-, 5-, and 10-year survival rates were, respectively, 91%, 82%, and 62% for cryoablation and 89%, 81%, and 55% for heat-based thermal ablation. After propensity score matching, cryoablation was associated with longer OS compared with heat-based thermal ablation (median 11.3 vs 10.4 years; hazard ratio 1.175, 95% CI 1.03-1.341; P = .016). For patients with tumors ≤2 cm, propensity score-matched analyses demonstrated no significant difference between the 2 treatment groups (P = .772).

CONCLUSIONS

Overall, cryoablation may be associated with longer OS compared with heat-based thermal ablation in cT1a RCC. No significant difference in survival rates was observed between the 2 treatments for patients with tumor sizes ≤2 cm. Owing to the inherent limitations of this study, further study with details on technology, local outcome, and complications is needed.

Combined chemoembolization and thermal ablation for the treatment of metastases to the liver

PURPOSE

The purpose of the study was to evaluate safety, time to recurrence, and overall survival (OS) in patients with liver metastases (LM), treated with transarterial chemoembolization (TACE) followed by ablation.

MATERIALS AND METHODS

This retrospective study included all patients with LM treated with combined TACE and ablation from August 1998 to September 2015. Forty-two patients (12 women, 30 men; age 62.9 ± 11.9 years) were treated for 44 LMs. Tumor characteristics, imaging response to treatment, recurrence, and OS data were reviewed. Statistical analysis included Kaplan-Meier estimation, Cox regression and Fisher's exact, Wilcoxon rank sum, or log rank tests.

RESULTS

Median follow-up was 10.3 months. Eighteen patients had 1 hepatic lesion, 16 had 2-5, and 8 had > 5. Median index lesion size was 4.7 cm (range 1.5-8 .0 cm). Tumor response (mRECIST) was available for 41/44 treated lesions, with CR in 32 (78.0%), PR in 8 (19.5%), and PD in 1 (2.4%). Long-term imaging follow-up was available for 38 patients. Freedom from local recurrence was 61% at 1 year and 50% at 2 years. OS was 55% at 1 year and 30% at 2 years (median OS, 14.5 months). Tumor size and histology were not predictors of time to progression or OS. Complications occurred in 19 patients (45%). Major complications occurred in 19% of patients and included hospitalization for fever (n = 2), hepatic abscess (n = 3) and fall requiring transfusion, portal vein thrombus causing lobar infarct, biliary fistula, and retroperitoneal hematoma (n = 1 each).

CONCLUSIONS

Combined TACE and ablation is effective for local tumor control of liver metastases up to 8 cm when part of a multidisciplinary treatment strategy. Major complications occurred in 19% of patients.

Endobronchial Forceps-Assisted and Excimer Laser-Assisted Inferior Vena Cava Filter Removal: The Data, Where We Are, and How It Is Done

The recognition of inferior vena cava filter related complications has motivated increased attentiveness in clinical follow-up of patients with inferior vena cava filters and has led to development of multiple approaches for retrieving filters that are challenging or impossible to remove using conventional techniques. Endobronchial forceps and excimer lasers are tools for designed to aid in complex inferior vena cava filter removals. This article discusses endobronchial forceps-assisted and excimer laser-assisted inferior vena cava filter retrievals.

Endovascular Removal of Inferior Vena Cava Filters with Arterial Penetration

PURPOSE

To evaluate the safety and outcomes of endovascular percutaneous removal of inferior vena cava filters (IVCFs) with elements penetrating an artery.

MATERIALS AND METHODS

From an IVCF retrieval database, computerized tomographic scans of patients who underwent IVCF retrieval from 2011 to 2017 were reviewed for IVCF elements penetrating through the caval wall and into an adjacent arterial wall (AW) or penetrating into an adjacent arterial lumen (AL). Forty-two patients were identified, including 20 with elements penetrating into an AW and 22 with elements penetrating into an AL; 30 of these IVCFs were tip embedded.

RESULTS

All of the filters in both groups were removed. Of the arterial-interacting filters, 9 were removed with the use of standard techniques and 33 with the use of endobronchial forceps. Arterial access was obtained before removal in 3 patients (7%) with post-removal arteriography revealing no abnormalities, such as extravasation, pseudoaneurysm, or new fractured components. There was no significant difference between groups in tip embedding, retrieval technique, or fluoroscopy time.

CONCLUSIONS

Endovascular removal of IVCFs with elements that have penetrated into adjacent arterial walls or lumens can be performed safely in the majority of patients.

Passive expansion of sub-maximally dilated transjugular intrahepatic portosystemic shunts and assessment of clinical outcomes

AIM

To assess for passive expansion of sub-maximally dilated transjugular intrahepatic portosystemic shunts (TIPS) and compare outcomes with maximally dilated TIPS.

METHODS

Polytetrafluoroethylene covered TIPS (Viatorr) from July 2002 to December 2013 were retrospectively reviewed at two hospitals in a single institution. Two hundred and thirty patients had TIPS maximally dilated to 10 mm (mTIPS), while 43 patients who were at increased risk for hepatic encephalopathy (HE), based on clinical evaluation or low pre-TIPS portosystemic gradient (PSG), had 10 mm TIPS sub-maximally dilated to 8 mm (smTIPS). Group characteristics (age, gender, Model for End-Stage Liver Disease score, post-TIPS PSG and clinical outcomes were compared between groups, including clinical success (ascites or varices), primary patency, primary assisted patency, and severe post-TIPS HE. A subset of fourteen patients with smTIPS underwent follow-up computed tomography imaging after TIPS creation, and were grouped based on time of imaging (< 6 mo and > 6 mo). Change in diameter and cross-sectional area were measured with 3D imaging software to evaluate for passive expansion.

RESULTS

Patient characteristics were similar between the smTIPS and mTIPS groups, except for pre-TIPS portosystemic gradient, which was lower in the smTIPS group (19.4 mmHg ± 6.8 vs 22.4 mmHg ± 7.1, P = 0.01). Primary patency and primary assisted patency between smTIPS and mTIPS was not significantly different (P = 0.64 and 0.55, respectively). Four of the 55 patients (7%) with smTIPS required TIPS reduction for severe refractory HE, while this occurred in 6 of the 218 patients (3%) with mTIPS (P = 0.12). For the 14 patients with follow-up computed tomography (CT) imaging, the median imaging follow-up was 373 d. There was an increase in median TIPS diameter, median percent diameter change, median area, and median percent area change in patients with CT follow-up greater than 6 mo after TIPS placement compared to follow-up within 6 mo (8.45 mm, 5.58%, 56.04 mm², and 11.48%, respectively, P = 0.01).

CONCLUSION

Passive expansion of smTIPS does occur but clinical outcomes of smTIPS and mTIPS were similar. Sub-maximal dilation can prevent complications related to over-shunting in select patients.

Analysis of the Final DENALI Trial Data: A Prospective, Multicenter Study of the Denali Inferior Vena Cava Filter

PURPOSE

To report the final 2-year data on the efficacy and safety of a nitinol retrievable inferior vena cava (IVC) filter for protection against pulmonary embolism (PE).

MATERIALS AND METHODS

This was a prospective multicenter trial of 200 patients with temporary indications for caval filtration who underwent implantation of the Denali IVC filter. After filter placement, all patients were followed for 2 years after placement or 30 days after filter retrieval. The primary endpoints were technical success of filter implantation in the intended location and clinical success of filter placement and retrieval. Secondary endpoints were incidence of clinically symptomatic recurrent PE, new or propagating deep vein thrombosis (DVT), and filter-related complications including migration, fracture, penetration, and tilt.

RESULTS

Filter placement was technically successful in 199 patients (99.5%). Filters were clinically successful in 190 patients (95%). The rate of PE was 3% (n = 6), with 5 patients having a small subsegmental PE and 1 having a lobar PE. New or worsening DVT was noted in 26 patients (13%). Filter retrieval was attempted 125 times in 124 patients and was technically successful in 121 patients (97.6%). The mean filter dwell time at retrieval was 200.8 days (range, 5-736 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of filter retrieval or during follow-up.

CONCLUSIONS

The Denali IVC filter exhibited high success rates for filter placement and retrieval while maintaining a low complication rate in this clinical trial.

Tumor Growth Kinetics and Oncologic Outcomes of Patients Undergoing Active Surveillance for Residual Renal Tumor following Percutaneous Thermal Ablation

PURPOSE

To evaluate growth kinetics and oncologic outcomes of patients with renal tumors undergoing active surveillance (AS) for residual viable tumor following percutaneous ablation.

MATERIALS AND METHODS

Following percutaneous thermal ablation, residual tumor was detected in 21/133 (16%) patients on initial follow-up imaging, and AS was undertaken in 17/21 (81%) patients. Initial tumor volumes and volumes after ablation were assessed from cross-sectional imaging to calculate volumetric growth rate (VGR) and volume doubling time (VDT) of residual tumor. The rate of metastasis, overall survival, and renal cell carcinoma (RCC)-specific survival were compared between patients in the AS group and in the routine follow up group of patients who did not have residual tumor.

RESULTS

Median tumor volume prior to ablation, after first ablation, and at final follow-up were 25 cm(3), 6 cm(3), and 6 cm(3), respectively, in patients with residual tumor. Stable, mild, and moderate VGR occurred in 8/17 (47%), 4/17 (24%), and 5/17 (29%) cases, respectively. The 4 cases with fastest VDT underwent delayed intervention with ablation (n = 1) and nephrectomy (n = 3) without subsequent residual, recurrence, or metastasis. There was no significant difference in the rates of RCC metastasis, overall survival, or RCC-specific survival between AS and routine follow-up groups. Metastatic RCC and subsequent death occurred in 1 patient in the AS group, after the patient had refused offers for retreatment for local progression over 60.7 months of follow-up.

CONCLUSIONS

In cases when patients are not amenable to further intervention, AS of residual tumor may be an acceptable alternative and allows for successful delayed intervention when needed.

Percutaneous biliary drainage effectively lowers serum bilirubin to permit chemotherapy treatment

PURPOSE

For digestive tract cancers, the bilirubin threshold for administration of systemic chemotherapy can be 5 or 2 mg/dL (85.5 or 34.2 μmol/L) depending upon the regimen. We examined the ability of percutaneous biliary drainage (PBD) in patients with malignant biliary obstruction to achieve these clinically relevant endpoints.

METHODS

106 consecutive patients with malignant biliary obstruction and a baseline serum bilirubin >2 mg/dL underwent PBD. Time to achieve a bilirubin of 5 mg/dL (85.5 μmol/L), 2 mg/dL (34.2 μmol/L), and survival was estimated by Kaplan-Meier analysis. Potential technical and clinical prognostic factors were subjected to univariate and multivariate analysis. Categorical variables were analyzed by the log rank test. Hazard ratios were calculated for continuous variables.

RESULTS

Median survival was 100 days (range 1-3771 days). Among 88 patients with a pre-drainage bilirubin >5 mg/dL, 62% achieved a serum bilirubin ≤5 mg/dL within 30 days and 84% within 60 days, median 21 days. Among 106 patients with a pre-drainage bilirubin >2 mg/dL, 37% achieved a serum bilirubin ≤2 mg/dL by 30 days and 70% within 60 days, median 43 days. None of the technical or clinical factors evaluated, including pre-drainage bilirubin, were significant predictors of time to achieve a bilirubin ≤2 mg/dL (p = 0.51). Size and type of biliary device were the only technical variables found to affect time to bilirubin of 5 mg/dL (p = 0.016).

CONCLUSION

PBD of malignant obstruction achieves clinically relevant reduction in serum bilirubin in the majority of patients within 1-2 months, irrespective of the pre-drainage serum bilirubin, sufficient to allow administration of systemic chemotherapy. However, the decision to undergo this procedure for this indication alone must be considered in the context of patients' prognosis and treatment goals.

Complication and Readmission Rates following Same-Day Discharge after Percutaneous Renal Tumor Ablation

PURPOSE

To evaluate readmission rate and complications in patients undergoing same-day discharge following percutaneous thermal ablation of renal tumors.

MATERIALS AND METHODS

Patients undergoing same-day discharge following thermal ablation of renal tumors were reviewed. The primary outcome was the rate of readmission within 30 days of same-day discharge. The secondary outcomes included the rate and clinical outcomes of periprocedural complications.

RESULTS

Same-day discharge occurred in 166/174 patients (95%), of whom 2/166 (1%) required short-term readmission due to pulmonary embolism and acute-on-chronic kidney injury. Both patients recovered without permanent morbidity. Admission due to complications occurred in 8/174 (5%) cases, the majority of which were related to hemorrhage. No significant differences in rates of complications or admission were found between cryoablation and RF ablation. Major complications (Clavien-Dindo grade II or higher, SIR grade C or higher) occurred in 7/174 (4%) cases, the majority related to hemorrhage. All cases were detected in the standard 4 hour postprocedural observation period and managed conservatively. The mean hemorrhage volume was significantly larger in patients requiring admission versus those discharged the same day (289 mL vs 34 mL; P = .02). Higher-volume hemorrhage occurred in larger tumors (mean, 4.0 cm vs 3.0 cm; P = .04). There was no association between major complications and central tumor or age.

CONCLUSIONS

Routine same-day discharge following percutaneous renal tumor thermal ablation can be performed with a low rate of short-term readmission. The majority of periprocedural complications can be managed conservatively, and patients can be discharged the same day.

Match day: online search trends reflect growing interest in IR training

Google Trends was used to characterize the relationship between the interventional radiology (IR) applicant pool and related Internet queries for "IR fellowship" from July 2006 to July 2013. Results were compared with National Residency Match Panel data by regression analysis and one-way analysis of variance. Search traffic for IR fellowship demonstrated a statistically significant linear annual increase (R(2) = 0.87; P = .0013). Total IR applicants increased by 184% (R(2) = 0.98; P = .0216). Search traffic was predictive of applicants for each match year (R(2) = 0.92; P = .0004) and programs filled (R(2) = 0.93; P = .0003). Internet queries mirror trainee professional interests, with significant increases in search traffic related to IR fellowship and strong correlation with growth in applicants.

Management of Endoleaks

The management of endoleaks remains an inherent challenge to endovascular aneurysm repair (EVAR), particularly as evolving techniques and devices have allowed treatment of increasingly complex aneurysm anatomy. Endovascular techniques are the favored modality for endoleak repair and include techniques to bridge the endoleak defector and embolize the endoleak nidus and inflow/outflow vessels. Conversion to surgical repair remains the definitive option in cases where less invasive methods have failed or are precluded. In this article, the authors review evidence on the indications, approach, and outcomes of current techniques for endoleak management.

Long-Term Patency and Clinical Analysis of Expanded Polytetrafluoroethylene-Covered Transjugular Intrahepatic Portosystemic Shunt Stent Grafts

PURPOSE

To evaluate long-term patency and symptomatic recurrence rates following transjugular intrahepatic portosystemic shunt (TIPS) creation with expanded polytetrafluoroethylene (ePTFE)-covered stent grafts and to determine the necessity of extended clinical follow-up beyond 2 years after TIPS creation.

MATERIALS AND METHODS

A retrospective review including 262 TIPSs created with ePTFE-covered stent grafts between July 2002 and October 2012 was performed. Primary, primary assisted, and secondary patency rates were calculated. Assessment of clinical data included technical, hemodynamic, and clinical success rates, as well as mortality after TIPS creation.

RESULTS

Primary patency rates at 2, 4, and 6 years were 74%, 62%, and 50%, respectively. Primary assisted patency rates at 2, 4, and 6 years were 93%, 85%, and 78%, respectively. Secondary patency rates at 2, 4, and 6 years were 99%, 91%, and 84%, respectively. Technical and hemodynamic success rates were 99% and 93%, respectively. Clinical success rates for refractory ascites were 66% (complete response) and 90% (partial response); clinical success rate for bleeding/varices was 90%. Mortality rates at 2, 4, and 6 years after TIPS creation were 27%, 38%, and 46%, respectively. At the median wait time until transplantation, patients had an 84% chance of being alive. TIPS dysfunction developed in 21% of patients; 30% of revisions occurred later than 2 years during follow-up.

CONCLUSIONS

Beyond 2 years after TIPS creation, patency rates gradually decrease, mortality rates continue to increase, and the chance of recurrent ascites or bleeding remains present. Together, these findings suggest that continued clinical follow-up beyond 2 years is necessary in patients with a TIPS created with an ePTFE-covered stent graft.

Long-term outcomes of a benign biliary stricture protocol

PURPOSE

To evaluate long-term outcomes of a structured protocol for percutaneous treatment of benign biliary stricture.

MATERIALS AND METHODS

Seventy-one patients (37 men, 34 women; mean age, 54 y; age range, 23-84 y) entered the protocol, which consisted of staged upsizing of internal/external biliary catheters, balloon dilation (nominally 8 mm), and prolonged stent treatment (6 mo) at maximal catheter size (nominally 18 F). It concluded with a capping trial and catheter removal if the stricture remained patent. Fifty-three patients completed the protocol and 18 did not (6 died, 6 underwent alternative treatment, 4 were lost to follow-up, and 2 underwent repeat transplantation). Stricture features, treatment parameters, complications, and outcomes were reviewed, and Kaplan-Meier analysis was conducted.

RESULTS

Strictures were anastomotic in 45 patients (64%), intrahepatic in 14 (20%), extrahepatic in 7 (10%), and multiple (intra- and extrahepatic) in 5 (7%). A right-sided approach was used in 47 patients (66%) patients, a left-sided approach in 18 (25%), and a bilateral approach in 6 (9%). Forty-six patients who entered the protocol (65%) and 46 patients who completed the protocol (87%) showed stricture patency. Four of 7 patients in whom a capping trial failed underwent surgical revision, 2 required chronic biliary drainage, and 1 received a metal stent. Follow-up (range, 0-12 y; mean, 4.7 y) was obtained for 42 of 53 patients who completed the protocol (79%). Kaplan-Meier analysis showed stricture patency probabilities of 84% at 1 year after treatment, 78% at 2 years, 74% at 5 years, and 67% at 10 years.

CONCLUSIONS

Use of a structured protocol for the percutaneous treatment of benign biliary strictures yields durable long-term results, suggesting that percutaneous treatment is an effective therapy.

The DENALI Trial: an interim analysis of a prospective, multicenter study of the Denali retrievable inferior vena cava filter

PURPOSE

To assess safety and effectiveness of a nitinol retrievable inferior vena cava (IVC) filter in patients who require caval interruption to protect against pulmonary embolism (PE).

MATERIALS AND METHODS

Two hundred patients with temporary indications for an IVC filter were enrolled in this prospective, multicenter clinical study. Patients undergoing filter implantation were to be followed for 2 years or for 30 days after filter retrieval. At the time of the present interim report, all 200 patients had been enrolled in the study, and 160 had undergone a retrieval attempt or been followed to 6 months with their filter in place. Primary study endpoints included technical and clinical success of filter placement and retrieval. Patients were also evaluated for recurrent PE, new or worsening deep vein thrombosis, and filter migration, fracture, penetration, and tilt.

RESULTS

Clinical success of placement was achieved in 94.5% of patients (172 of 182), with a one-sided lower limit of the 95% confidence interval of 90.1%. Technical success rate of filter placement was 99.5%. Technical success rate of retrieval was 97.3%; 108 filters were retrieved in 111 attempts. In two cases, the filter apex could not be engaged with a snare, and one device was engaged but could not be removed. Filter retrievals occurred at a mean indwell time of 165 days (range, 5-632 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of retrieval or 6-month follow-up.

CONCLUSIONS

In this interim report, the nitinol retrievable IVC filter provided protection against pulmonary embolism, and the device could be retrieved with a low rate of complications.

Outcomes of percutaneous interventions in transposed hemodialysis fistulas compared with nontransposed fistulas and grafts

PURPOSE

To compare postpercutaneous intervention outcomes of autogenous venous-transposition arteriovenous fistulas (AVFs) versus those of autogenous nontransposed AVFs (nAVFs) and prosthetic arteriovenous grafts (AVGs).

MATERIALS AND METHODS

A total of 591 hemodialysis accesses (195 transposed AVFs [tAVFs], 205 nAVFs, 191 AVGs) in 522 patients (278 male; mean age, 57 y; range, 15–91 y) underwent percutaneous transluminal angioplasty (PTA) and/or mechanical thrombectomy (ie, declotting). Access characteristics, surgical history, percutaneous interventions, postinterventional primary and secondary access patency, and follow-up data were collected. Cox proportional-hazards regression analyses, Fisher exact tests, and χ2 tests were performed.

RESULTS

Mean follow-up period was 32 months. Mean access ages at initial percutaneous intervention were 260 days (tAVF), 206 days (nAVF), and 176 days (AVG; P < .01). One-year postinterventional primary patency (PIPP) rates were 25% (tAVF), 24% (nAVF), and 14% (AVG). One-year postinterventional secondary patency (PISP) rates were 77% (tAVF), 61% (nAVF), and 63% (AVG). Median PIPP durations were 138 days (tAVF), 121 days (nAVF), and 79 days (AVG; P = .0001). Median PISP durations were 1,076 days (tAVF), 783 days (nAVF), and 750 days (AVG; P = .019). Total interventions needed to maintain PISP were 2.4 (tAVF), 1.3 (nAVF), and 3.2 (AVG) per patient-year (P < .001), which included 1.9, 1.2, and 1.4 PTAs (P < .01) and 0.45, 0.15, and 1.8 declotting procedures, respectively (P < .001).

CONCLUSIONS

Based on the number of percutaneous interventions needed to maintain PISP, these results confirm the current Dialysis Outcomes Quality Initiative access preference of nAVFs before tAVFs before AVGs. tAVFs offered superior postinterventional outcomes than AVGs. With additional interventions, tAVFs could even outperform nAVFs in terms of PISP.

Comparison of polyvinyl alcohol microspheres and tris-acryl gelatin microspheres for uterine fibroid embolization: results of a single-center randomized study

PURPOSE

To assess the efficacy of two embolic agents in the treatment of symptomatic uterine leiomyomas.

MATERIALS AND METHODS

A randomized, prospective, single-center study enrolled 60 women with symptomatic uterine leiomyomas. Uterine artery embolization (UAE) with spherical polyvinyl alcohol (SPVA) microspheres (n = 30; 700-900 μm and 900-1,200 μm; near-stasis or stasis endpoint) and tris-acryl gelatin (TAG) microspheres (n = 30; 500-700 μm; "pruned-tree" endpoint) was performed. Infarction rates were calculated for the dominant tumor and for small (< 2 cm) and large (> 2 cm) nondominant tumors. The primary endpoint was tumor infarction at 24 hours measured by contrast-enhanced magnetic resonance imaging assessed by a blinded reviewer.

RESULTS

Baseline characteristics were similar between groups. The primary endpoint was similar in both treatments (≥ 91% dominant tumor infarction; SPVA. 86.2%; TAG, 93.3%, P = .35). Complete infarction (100%) was also similar between arms at 24 hours and 3 months. Symptom severity was reduced and quality of life improved equally at 3 and 12 months in each treatment group. Complications were minor in both groups.

CONCLUSIONS

Uterine leiomyoma infarction at 24 hours and 3 months after treatment with SPVA or TAG microspheres was comparable when using near-stasis as a procedural endpoint with SPVA microspheres. Symptom relief was maintained for as long as 12 months for both embolic agents.

Chest radiograph-based algorithm for managing malfunctioning ports

PURPOSE

To evaluate a chest x-ray-based algorithm for managing malfunctioning ports.

MATERIALS AND METHODS

A review of interventional radiology procedures on malfunctioning ports during the period 2000-2012 was performed. Events were divided into two periods: before and after implementation of an algorithm beginning with tip position evaluation using a chest x-ray. Time to return to usability, frequency of interventions to restore function, and frequency of malfunctioning ports remaining in use after the procedure were calculated.

RESULTS

The review included 303 procedures before implementation of the algorithm on 237 access sites in 227 patients (mean age, 56 y; 38% male) and 155 procedures after implementation of the algorithm on 131 access sites in 130 patients (mean age, 55 y; 35% male). Implementation of the algorithm was associated with significantly fewer repeat checks on the same access (27% before algorithm, 9% after algorithm, P < .001) and reduced frequency of a malfunctioning port remaining in use after the interventional radiology procedure (43% before algorithm to 14% after algorithm, P < .001). Median time from consultation to revision was significantly less after implementing the algorithm (13 days before algorithm, 1 day after algorithm, P < .001). Median time from consultation to port usability was also less after implementing the algorithm (2.7 days before algorithm, 1 day after algorithm, P < .001).

CONCLUSIONS

Implementation of the algorithm was associated with significantly less frequent repeat procedures on the same port and a lower frequency of malfunctioning ports remaining in place. Use of the algorithm was associated with significantly reduced time from consultation to revision and to return to usability. These findings suggest the algorithm allows triage of patients with malfunctioning ports to the appropriate intervention before undergoing a procedure.

Improving retrieval rates for retrievable inferior vena cava filters

The introduction of retrievable inferior vena cava (IVC) filters was an important step in the evolution of deep vein thrombosis/pulmonary embolism management. Their removability makes them preferred to permanent filters in many cases. IVC filter retrieval often occurs at a suboptimal rate, leading to complications associated with long-term placement. Improving retrievability includes solutions for patients being lost to follow-up, filter malpositioning, need arising for permanent IVC filtration, filtration requiring longer than the filter's window of retrievability, and filter compromise by the presence of a large trapped clot. This review explores these strategies for retrieval in detail in hopes of improving IVC filter retrieval rates.

Objective and subjective assessment of physician labor and resource utilization in maintenance percutaneous transluminal angioplasty of nonthrombosed hemodialysis arteriovenous fistulas versus arteriovenous grafts

PURPOSE

To complement prior studies that have shown that arteriovenous fistula (AVF) thrombectomies require more time and equipment than arteriovenous graft (AVG) thrombectomies by measuring work via established instruments to determine whether there is also a difference in maintenance percutaneous transluminal angioplasty (PTA) of nonthrombosed AVFs versus AVGs.

MATERIALS AND METHODS

PTA procedures performed on a consecutive cohort of 42 patients with AVFs and 27 patients with AVGs were prospectively compared. To quantify resource utilization, procedure time and disposable equipment were measured. Established instruments developed by the American Medical Association for Current Procedural Terminology code valuation were used to measure subjective "physician work," including mental effort and judgment, technical skill, physical effort, and psychological stress. These items were scored by 1 of 12 attending interventional radiology physicians performing the procedure.

RESULTS

Mean PTA procedure time was 74 minutes (range, 18-183 minutes) for AVFs and 71 minutes (range, 28-204 minutes) for AVGs; hemostasis time was 12 minutes for AVFs and 11 minutes for AVGs. There was no significant difference in equipment use between groups. "Physician work" for AVFs scored significantly higher in four categories (P≤ .05).

CONCLUSIONS

Using established subjective instruments, maintenance PTA of AVFs was scored as more cognitively, physically, and psychologically demanding than maintenance PTA of AVGs. However, there was no significant difference in resource utilization between maintenance PTA of AVFs versus AVGs, as has been previously shown with thrombectomy of thrombosed AVFs and AVGs.

Inferior vena cava filters for primary prophylaxis: when are they indicated?

Over the past several years there has been a rapid increase in the number of inferior vena cava (IVC) filters placed for primary thromboprophylaxis. Increased use has occurred in settings where other methods of thromboprophylaxis are viewed to be inadequate, technically challenging, or that place patients at an unacceptably high bleeding risk. These clinical services include trauma, bariatric surgery, neurosurgery, cancer, intensive care unit populations, and patients with a relative contraindication to anticoagulation. We review the studies to date addressing filter placement for these indications. Although preliminary data are promising, the patient populations most likely to benefit from prophylactic IVC filter placement have not been well defined, and randomized studies demonstrating efficacy have not been conducted. Moving forward, it will be critical to accomplish these two tasks if IVC filters are to continue to have a role in primary thromboprophylaxis.

Impact on renal function of percutaneous thermal ablation of renal masses in patients with preexisting chronic kidney disease

PURPOSE

To examine the effect of percutaneous thermal ablation of renal masses on renal function among patients with baseline chronic kidney disease (CKD).

MATERIALS AND METHODS

Patients with baseline CKD (initial glomerular filtration rate [GFR] < 60 mL/min/1.73 m(2)) who underwent percutaneous cryoablation or radiofrequency (RF) ablation of renal masses were reviewed.

RESULTS

A total of 48 patients with a GRF of 60 mL/min/1.73 m(2) or lower were treated with renal cryoablation or RF ablation and had follow-up GFR measurement 1 month afterward. Mean patient age was 73 years (range, 47-89 y). Cryoablation was performed in 22 patients and RF ablation was performed in 26. Mean tumor diameter was 3.4 cm (range, 0.9-10.2 cm). Mean overall GFRs were 39.8 mL/min/1.73 m(2) at baseline and 39.7 mL/min/1.73 m(2) at 1 month after ablation (P = .85). A total of 38 patients had 1-year follow-up GFR measurement (cryoablation, n = 18; RF ablation, n = 20), and their mean GFR was 40.9 mL/min/1.73 m(2) ± 11.4 (SD), compared with a preablation GFR of 41.2 mL/min/1.73 m(2)(P = .79). In the cryoablation group, mean GFRs at 1 month and 1 year were 41.4 mL/min/1.73 m(2) and 44.4 mL/min/1.73 m(2), compared with respective baseline GFRs of 41.1 mL/min/1.73 m(2) and 42.1 mL/min/1.73 m(2) (P = .75 and P = .19, respectively). In the RF ablation group, mean GFRs at 1 month and 1 year were 38.2 mL/min/1.73 m(2) and 37.8 mL/min/1.73 m(2), compared with respective baseline GFRs of 38.7 mL/min/1.73 m(2) and 40.4 mL/min/1.73 m(2) (P = .58 and P = .09, respectively).

CONCLUSIONS

Independent of ablation modality, percutaneous renal mass ablation does not appear to affect renal function among patients with CKD.

Management of Endoleaks following Endovascular Aneurysm Repair

Endovascular aneurysm repair (EVAR) has emerged as a viable alternative to open repair for abdominal aortic aneurysms. Endoleaks are a complication unique to EVAR and can occur in up to 25% of patients. In this article, the management of endoleaks following EVAR will be discussed.