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.

Correlation and Agreement of Yttrium-90 Positron Emission Tomography/Computed Tomography with Ex Vivo Radioembolization Microsphere Deposition in the Rabbit VX2 Liver Tumor Model.

PURPOSE: To demonstrate a stronger correlation and agreement of yttrium-90 (90Y) positron emission tomography (PET)/computed tomography (CT) measurements with explant liver tumor dosing compared with the standard model (SM) for radioembolization. MATERIALS AND METHODS: Hepatic VX2 tumors were implanted into New Zealand white rabbits, with growth confirmed by 7 T magnetic resonance imaging. Seventeen VX2 rabbits provided 33 analyzed tumors. Treatment volumes were calculated from manually drawn volumes of interest (VOI) with three-dimensional surface renderings. Radioembolization was performed with glass 90Y microspheres. PET/CT imaging was completed with scatter and attenuation correction. Three-dimensional ellipsoid VOI were drawn to encompass tumors on fused images. Tumors and livers were then explanted for inductively coupled plasma (ICP)-optical emission spectroscopy (OES) analysis of microsphere content. 90Y PET/CT and SM measurements were compared with reference standard ICP-OES measurements of tumor dosing with Pearson correlation and Bland-Altman analyses for agreement testing with and without adjustment for tumor necrosis. RESULTS: The median infused activity was 33.3 MBq (range, 5.9-152.9). Tumor dose was significantly correlated with 90Y PET/CT measurements (r = 0.903, P < .001) and SM estimates (r = 0.607, P < .001). Bland-Altman analyses showed that the SM tended to underestimate the tumor dosing by a mean of -8.5 Gy (CI, -26.3-9.3), and the degree of underestimation increased to a mean of -18.3 Gy (CI, -38.5-1.9) after the adjustment for tumor necrosis. CONCLUSIONS: 90Y PET/CT estimates were strongly correlated and had better agreement with reference measurements of tumor dosing than SM estimates.

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.

Inferior Vena Cava Filter Retrieval: Patient Selection, Procedural Planning, and Postprocedural Complications.

OBJECTIVE. Utilization of retrievable inferior vena cava filters (rIVCFs) has come under increased scrutiny because of historically high rates of placement, generalized lack of retrieval when the inferior vena cava filter (IVCF) is no longer indicated, and reports of device-related complications. These events have led to an increased interest in IVCF retrieval, including the development of advanced endovascular retrieval techniques and the proliferation of specialized clinical practices for rIVCFs. We aim to describe the indications for IVCF retrieval, patient selection, procedural planning, and procedural complications and management. CONCLUSION. IVCFs continue to have a role in the prevention of pulmonary embolism in select patients. Rising awareness of device-related complications paired with historically low retrieval rates has prompted renewed emphasis and interest in filter retrieval. Diligent follow-up and procedural planning permit prompt and safe filter retrieval.

Recent Trends in Clinical Setting and Provider Specialty for Endovascular Peripheral Artery Disease Interventions for the Medicare Population.

PURPOSE: To describe national trends in peripheral endovascular interventions by physician specialty, anatomic segment of disease, and clinical location of service. MATERIALS AND METHODS: Current Procedural Terminology codes were used to identify claims for peripheral vascular interventions (PVIs) in 2011-2017 Physician Supplier Procedure Summary master files, which contain 100% Part B Medicare billing. Market share was defined as enrollment-adjusted proportion of billed PVI services for each specialty. Annual volume of billed services was additionally evaluated by clinical location (inpatient, outpatient, office-based laboratories) and anatomic segment of disease (iliac, femoral/popliteal, infrapopliteal). RESULTS: Aggregate PVI claims increased 31.3%, from 227,091 in 2011 to 298,127 in 2017. Annual market share remained relatively stable for all specialties: surgery, 48.3%-49.6%; cardiology, 37.2%-35.1%; radiology, 12.8%-13.3%. Accounting for Medicare enrollment, the volume of iliac interventions decreased by 18% over the study period, while femoral/popliteal interventions increased modestly (+7.5%) and infrapopliteal interventions increased (+46%). The greatest proportional increase in infrapopliteal claims occurred among radiologists (surgeons +40.4%, cardiologists +32.1%, radiologists +106.6%). Adjusting for enrollment, claims from office-based laboratories increased substantially (+305.7%), while hospital-based billing decreased (inpatient -25.7%, outpatient -12.9%). Office-based laboratory utilization increased dramatically with all specialties (surgery +331.8%, cardiology +256.0%, radiology +475.7%). CONCLUSIONS: Utilization of PVIs continues to increase, while specialty market shares have stabilized since 2011, leaving surgeons and cardiologists as the major providers of endovascular peripheral artery disease care. The greatest relative increases are occurring in infrapopliteal interventions and office-based laboratory procedures, where radiologist involvement has increased dramatically.

Gender Disparity in Inpatient Mortality After Transjugular Intrahepatic Portosystemic Shunt Creation in Patients Admitted With Hepatorenal Syndrome: A Nationwide Study.

PURPOSE: The aim of this study was to evaluate inpatient mortality after transjugular intrahepatic portosystemic shunt (TIPS) creation compared with medical management (MM) in patients with hepatorenal syndrome (HRS). METHODS: Patients with cirrhosis admitted with HRS between 2005 and 2014 were identified using associated International Classification of Diseases, Ninth Revision, codes in the National Inpatient Sample (n = 153,112). Non-TIPS candidates and patients with parenchymal renal disease were excluded (n = 73,454). The remaining admissions were assigned to groups of TIPS (International Classification of Diseases, Ninth Revision, code 39.1; n = 971) or MM (n = 78,687). Inpatient mortality was analyzed by treatment type and patient gender using χ2 tests. Logistic regression was performed to control for baseline differences in patient demographics, comorbid disease, and pretreatment mortality risk. RESULTS: Baseline patient demographics were similar. Patients treated medically had higher baseline disease severity (median mortality risk score, 8.3 with MM versus 6.1 with TIPS; P < .01). Inpatient mortality was strongly modified by patient gender. TIPS creation conferred inpatient mortality benefit in men (28% of the MM group versus 10% of the TIPS group, P < .01) independent of all covariates (odds ratio, 0.4; 95% confidence interval, 0.17-0.78; P < .01). Women treated with TIPS creation experienced no mortality benefit (29% MM versus 32% TIPS; odds ratio, 1.5; 95% confidence interval, 0.75-3.23; P = .23). CONCLUSIONS: TIPS creation is associated with reduced inpatient mortality in men, but not women, admitted with HRS. Drivers of this gender-based disparity are currently unclear and warrant focused investigation.

Clinical Practice Characteristics of Radiologists Based on American Board of Radiology Interventional Radiology Certification Status.

OBJECTIVE. The objective of this study was to assess clinical practice characteristics of radiologists on the basis of American Board of Radiology (ABR) interventional radiology (IR) certification status. MATERIALS AND METHODS. Medicare-participating radiologists were linked with ABR diplomates using the ABR's public search engine. Radiologists with an interventional radiology/diagnostic radiology (IR/DR) certificate (offered since 2017) were deemed currently IR-certified (n = 2840), and those assigned a vascular and interventional radiology subspecialty certificate (now defunct by the ABR) were deemed previously IR-certified (n = 900). Physician characteristics were obtained from Centers for Medicare & Medicaid Services (CMS) data. RESULTS. Overall, the mean percentage work effort in IR was higher for radiologists currently IR-certified than it was for radiologists who were previously IR-certified (65.9% vs 30.6%). Although 41.2% of currently IR-certified diplomates had more than 90% IR work effort, 35.7% had 50% or less IR work effort. Radiologists with current IR certification versus those with previous IR certification were more likely to be in an academic practice (25.1% vs 8.4%), a larger practice (in a practice with ≥ 100 members, 41.2% vs 22.4%), and earlier career stages (≤ 20 years in practice, 46.5% vs 0.6%). Of the 10 services most commonly billed by currently versus previously IR-certified radiologists, two and zero, respectively, were invasive procedures. Of identified CMS-participating radiologists with more than 50% IR effort, 27.2% (727/2670) were neither previously nor currently IR-certified. CONCLUSION. Although radiologists maintaining IR certification have higher IR work effort than those whose IR certification has lapsed, they are heterogeneous with overall sizable noninvasive diagnostic imaging practices. Approximately one-quarter of radiologists with predominant IR practices have never obtained IR certification. Because current IR/DR maintenance of certification testing exclusively addresses IR practice, attention is warranted to ensure certification is relevant to all IR diplomates.

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.