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Purpose: To present the results of the Liquid Embolization of Arterial Hemorrhages in Peripheral Vasculature (LAVA) study evaluating safety and efficacy of Lava Liquid Embolic System (Lava LES), an ethylene vinyl alcohol (EVOH), for peripheral arterial hemorrhage (PAH)., Materials and Methods: LAVA was a pivotal, prospective, multicenter, single-group, centrally adjudicated study of adults with active PAH. Patients received EVOH at one of two viscosities, administered by experienced physicians. Primary safety endpoint was freedom from 30-day major adverse events (MAE) defined as ischemia/infarction of target territory, non-target embolization, allergic reaction, and catheter breakage/entrapment. Primary efficacy endpoint was 30-day clinical success defined as absence of bleeding from target lesion after embolization without need for emergency surgery, re-embolization, or other target lesion re-interventions. Secondary endpoints included serious adverse events and mortality., Results: 113 patients (mean age 57.4 years [SD 18.0; range 18.0-93.0]; 63.7% male) with 148 lesions were enrolled at 19 US centers. Targeted areas included non-gastrointestinal (GI) visceral arteries (31.1%), kidneys (26.3%), upper GI (11.5%), lower GI (6.8%) and extremities (6.1%). Empiric embolization was performed for 20.9% of lesions. The primary efficacy endpoint was achieved in 94.3% of lesions (95.3% patients), exceeding the performance goal of 72%. Two target lesions treated with EVOH required subsequent re-embolization. No surgeries were performed for bleeding or ischemia. There were no MAEs reported per study definition. All-cause mortality rate at 30 days was 8.3%., Conclusions: The LAVA study suggests that EVOH is effective and can be safely used as an embolic agent for treatment of PAH., (Copyright © 2024. Published by Elsevier Inc.)

Registry data are being increasingly used to establish treatment guidelines, set benchmarks, allocate resources, and make payment decisions. Although many registries rely on manual data entry, the Society of Interventional Radiology (SIR) is using automated data extraction for its VIRTEX registry. This process relies on participants using consistent terminology with highly structured data in physician-developed standardized reports (SR). To better understand barriers to adoption, a survey was sent to 3,178 SIR members. Responses were obtained from 451 interventional radiology practitioners (14.2%) from 92 unique academic and 151 unique private practices. Of these, 75% used structured reports and 32% used the SIR SR. The most common barriers to the use of these reports include SR length (35% of respondents), lack of awareness about the SR (31%), and lack of agreement on adoption within practices (27%). The results demonstrated insights regarding barriers in the use and/or adoption of SR and potential solutions., (Copyright © 2023 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare secondary outcomes after ablation (AB), surgical resection (SR), and liver transplant (LT) for small hepatocellular carcinomas (HCCs), including resource utilization and adverse event (AE) rates., Materials and Methods: Using Surveillance, Epidemiology, and End Results Program (SEER)-Medicare, HCCs <5 cm that were treated with AB, SR, or LT in 2009-2016 (n = 1,067) were identified using Healthcare Common Procedure Coding System codes through Medicare claims. Index procedure length of stay, need for intensive care unit (ICU) level care, readmission rates, and AE rates at 30 and 90 days were compared using chi-square tests or Fisher exact tests. Examined AEs included hemorrhage, abscess formation, biliary injury, pneumonia, sepsis, liver disease-related AEs, liver failure, and anesthesia-related AEs, identified by International Classification of Diseases, Ninth/10th Revision, codes., Results: The median length of stay for initial treatment was 1 day, 6 days, and 7 days for AB, SR, and LT, respectively (P < .001). During initial hospital stay, 5.0%, 40.8%, and 63.4% of AB, SR, and LT cohorts, respectively, received ICU-level care (P < .001). By 30 and 90 days, there were significant differences among the AB, SR, and LT cohorts in the rate of postprocedural hemorrhage, abscess formation, biliary injury, pneumonia, sepsis, liver disease-related AEs, and anesthesia-related AEs (P < .05). By 90 days, the readmission rates after AB, SR, and LT were 18.6%, 28.2%, and 40.6% (P < .001), respectively., Conclusions: AB results in significantly less healthcare utilization during the initial 90 days after procedure compared with that after SR and LT due to shorter length of stay, lower intensity care, fewer readmissions, and fewer AEs., (Copyright © 2023. Published by Elsevier Inc.)

Objective: To determine the safety and effectiveness of vena cava filters (VCFs)., Methods: A total of 1429 participants (62.7 ± 14.7 years old; 762 [53.3% male]) consented to enroll in this prospective, nonrandomized study at 54 sites in the United States between October 10, 2015, and March 31, 2019. They were evaluated at baseline and at 3, 6, 12, 18, and 24 months following VCF implantation. Participants whose VCFs were removed were followed for 1 month after retrieval. Follow-up was performed at 3, 12, and 24 months. Predetermined composite primary safety (freedom from perioperative serious adverse events [AEs] and from clinically significant perforation, VCF embolization, caval thrombotic occlusion, and/or new deep vein thrombosis [DVT] within 12-months) and effectiveness (composite comprising procedural and technical success and freedom from new symptomatic pulmonary embolism [PE] confirmed by imaging at 12-months in situ or 1 month postretrieval) end points were assessed., Results: VCFs were implanted in 1421 patients. Of these, 1019 (71.7%) had current DVT and/or PE. Anticoagulation therapy was contraindicated or had failed in 1159 (81.6%). One hundred twenty-six (8.9%) VCFs were prophylactic. Mean and median follow-up for the entire population and for those whose VCFs were not removed was 243.5 ± 243.3 days and 138 days and 332.6 ± 290 days and 235 days, respectively. VCFs were removed from 632 (44.5%) patients at a mean of 101.5 ± 72.2 days and median 86.3 days following implantation. The primary safety end point and primary effectiveness end point were both achieved. Procedural AEs were uncommon and usually minor, but one patient died during attempted VCF removal. Excluding strut perforation greater than 5 mm, which was demonstrated on 31 of 201 (15.4%) patients' computed tomography scans available to the core laboratory, and of which only 3 (0.2%) were deemed clinically significant by the site investigators, VCF-related AEs were rare (7 of 1421, 0.5%). Postfilter, venous thromboembolic events (none fatal) occurred in 93 patients (6.5%), including DVT (80 events in 74 patients [5.2%]), PE (23 events in 23 patients [1.6%]), and/or caval thrombotic occlusions (15 events in 15 patients [1.1%]). No PE occurred in patients following prophylactic placement., Conclusions: Implantation of VCFs in patients with venous thromboembolism was associated with few AEs and with a low incidence of clinically significant PEs., (Copyright © 2023 Society of Interventional Radiology and Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Purpose: To provide evidence-based recommendations on the use of inferior vena cava (IVC) filters in the treatment of patients with or at substantial risk of venous thromboembolic disease., Materials and Methods: A multidisciplinary expert panel developed key questions to address in the guideline, and a systematic review of the literature was conducted. Evidence was graded based on a standard methodology, which was used to inform the development of recommendations., Results: The systematic review identified a total of 34 studies that provided the evidence base for the guideline. The expert panel agreed on 18 recommendations., Conclusions: Although the evidence on the use of IVC filters in patients with or at risk of venous thromboembolic disease varies in strength and quality, the panel provides recommendations for the use of IVC filters in a variety of clinical scenarios. Additional research is needed to optimize care for this patient population., (Copyright © 2020 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To report final 2-year outcomes with the Sentry bioconvertible inferior vena cava (IVC) filter in patients requiring temporary protection against pulmonary embolism (PE)., Materials and Methods: In a prospective multicenter trial, the Sentry filter was implanted in 129 patients with documented deep vein thrombosis (DVT) and/or PE (67.5%) or who were at temporary risk of developing DVT/PE (32.6%). Patients were monitored and bioconversion status ascertained by radiography, computed tomography (CT), and CT venography through 2 years., Results: The composite primary 6-month endpoint of clinical success was achieved in 97.4% (111/114) of patients. The rate of new symptomatic PE was 0% (n = 126) through 1 year and 2.4% (n = 85) through the second year of follow-up, with 2 new nonfatal cases at 581 and 624 days that were adjudicated as not related to the procedure or device. Two patients (1.6%) developed symptomatic caval thrombosis during the first month and underwent successful interventions without recurrence. No other filter-related symptomatic complications occurred through 2 years. There was no filter tilting, migration, embolization, fracture, or caval perforation and no filter-related deaths through 2 years. Filter bioconversion was successful for 95.7% (110/115) of patients at 6 months, 96.4% (106/110) of patients at 12 months, and 96.5% (82/85) of patients at 24 months. Through 24 months of follow-up, there was no evidence of late-stage IVC obstruction or thrombosis after filter bioconversion or of thrombogenicity associated with retracted filter arms., Conclusions: The Sentry IVC filter provided safe and effective protection against PE, with a high rate of intended bioconversion and a low rate of device-related complications, through 2 years of follow-up., (Copyright © 2019 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To prospectively assess the Sentry bioconvertible inferior vena cava (IVC) filter in patients requiring temporary protection against pulmonary embolism (PE)., Materials and Methods: At 23 sites, 129 patients with documented deep vein thrombosis (DVT) or PE, or at temporary risk of developing DVT or PE, unable to use anticoagulation were enrolled. The primary end point was clinical success, including successful filter deployment, freedom from new symptomatic PE through 60 days before filter bioconversion, and 6-month freedom from filter-related complications. Patients were monitored by means of radiography, computerized tomography (CT), and CT venography to assess filtering configuration through 60 days, filter bioconversion, and incidence of PE and filter-related complications through 12 months., Results: Clinical success was achieved in 111 of 114 evaluable patients (97.4%, 95% confidence interval [CI] 92.5%-99.1%). The rate of freedom from new symptomatic PE through 60 days was 100% (n = 129, 95% CI 97.1%-100.0%), and there were no cases of PE through 12 months for either therapeutic or prophylactic indications. Two patients (1.6%) developed symptomatic caval thrombosis during the first month; neither experienced recurrence after successful interventions. There was no filter tilting, migration, embolization, fracture, or caval perforation by the filter, and no filter-related death through 12 months. Filter bioconversion was successful for 95.7% (110/115) at 6 months and for 96.4% (106/110) at 12 months., Conclusions: The Sentry IVC filter provided safe and effective protection against PE, with a high rate of intended bioconversion and a low rate of device-related complications, through 12 months of imaging-intense follow-up., (Copyright © 2018 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the effectiveness and safety of yttrium-90 transarterial radioembolization (TARE) for the treatment of primary and metastatic soft tissue sarcoma (STS) of the liver., Materials and Methods: A retrospective review of 39 patients with primary (n = 2) and metastatic (n = 37) hepatic STS treated with TARE at 4 institutions was performed. Fourteen STS subtypes were included, with leiomyosarcoma being the most common (51%). TARE with glass (22 patients) or resin (17 patients) microspheres was performed, with single lobe (17 patients) or bilobar treatment (22 patients) based on disease burden. Adverse events of treatment, overall survival (OS), and tumor response at 3, 6, and 12 months after TARE were assessed per the Response Evaluation Criteria in Solid Tumors., Results: Fourteen patients demonstrated either partial or complete response to therapy, with an objective response rate of 36%. Thirty patients (77%) demonstrated disease control (DC)-either stable disease or response to treatment. Median OS was 30 months (95% confidence interval 12-43 months) for all patients. DC at 3 months was associated with an increased median OS (44 months) compared with progressive disease (PD) (7.5 months; P < .0001). Patients with DC at 6 months also demonstrated an increased median OS (38 months) compared to patients with PD (17 months; P = .0443). Substantial adverse events included 1 liver abscess, 1 gastric ulceration, and 1 pneumonitis., Conclusions: Patients with hepatic STS treated with TARE demonstrated a high rate of DC and a median OS of 30 months, which suggests a role for TARE in the palliation of hepatic STS., (Copyright © 2018 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To characterize the unique experiences, values, and perspectives of interventional radiology (IR) fellows., Materials and Methods: Sixteen fellows from 4 US vascular and IR programs were interviewed within 2 months of beginning and 2-3 months following their 2015-2016 fellowships about patient interactions, training experiences, and views of IR and other specialties. Interviews were systematically analyzed for dominant themes by using constructivist grounded theory. Four interviews with 2015-2016 interventional cardiology fellows, 16 interviews with IR attending physicians, and online descriptions of IR were also analyzed for context. Themes were compared qualitatively and quantitatively., Results: Interobserver agreement was good for interview themes (κ = 0.70; P < .0001). IR fellows' professional identity emerged primarily from radiologic and surgical interests, with distinct emphasis on being "innovators," "thinking differently," and "needing to adapt and advertise abilities to survive." Fellows' descriptions of patient care were more clinically focused than past interviews with attending physicians (P = .05), but clinical interests common in medical specialties were limited, and descriptions of "nonprocedural patient care" were primarily periprocedural (81%). Descriptions of the future of the field conveyed competing pressures, loose role definition, and disconnect between academic and private-practice IR., Conclusions: IR fellows share professional interests, views of their field and others, and descriptions of patient care, but there is uncertainty regarding future roles of the specialty and a need for more specific and unified definitions of nonprocedural patient care in IR., (Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate whether technetium-99 ( 99m Tc)-labeled macroaggregated albumin (MAA) can predict subsequent yttrium-90 ( 90 Y) distribution and imaging response in patients with hepatocellular carcinoma (HCC)., Materials: Retrospective review was performed of records of 83 patients with HCC who underwent 90 Y glass microsphere radioembolization with 99m Tc-MAA single photon emission computed tomography (SPECT) and 90 Y positron emission tomography (PET)/CT between January 2013 and December 2014. Images were fused to segment the whole liver normal tissue (WLNT) and the largest tumors. Fused images were reviewed and analyzed for comparison of absorbed dose (AD) to tumors and WLNT as calculated from 99m Tc-MAA SPECT and from 90 Y PET/CT, subjective imaging comparison of 99m Tc-MAA SPECT and 90 Y PET for tumors and WLNT, and correlation of tumoral AD with response on follow-up CT., Results: Final analysis included 73 and 63 patients for WLNT and tumor 99m Tc-MAA/ 90 Y correlation, respectively, and 62 patients for AD vs response. 99m Tc-MAA/ 90 Y limit of agreement for each reviewer was viewed as clinically acceptable only for WLNT (-15 to 15 Gy). AD interreviewer variability was clinically acceptable for WLNT but was too broad for tumor. Mean tumor AD for objective response (78%) was 313 Gy vs 234 Gy for nonresponders. No threshold was found between tumor AD and response (P > .1). Catheter mismatch between 99m Tc-MAA and 90 Y had a direct impact on AD mismatch between the 2 image sets., Conclusions: 99m Tc-MAA was found to be a poor surrogate to quantitatively predict subsequent 90 Y AD to hepatocellular tumors. 99m Tc-MAA distribution correlated with 90 Y distribution in the normal hepatic parenchyma., (Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To characterize the distribution of absorbed radiation dose after glass microsphere radioembolization for hepatocellular carcinoma (HCC) using yttrium-90 ((90)Y) positron emission tomography/computed tomography (PET/CT)., Materials and Methods: In this retrospective study, 64 (90)Y PET/CT scans performed after treatment were evaluated following (90)Y glass-bead radioembolization in patients with advanced HCC. The intended dose to the target volume ranged from 83-129 Gy. Three-dimensional "dose maps" were created from reconstructed PET images using a voxel-based S-value transformation. Liver parenchyma and liver tumors were contoured on cross-sectional imaging and aligned with the created dose maps., Results: There were 113 tumors examined as part of 64 lobar treatments. The average tumor size was 4.8 cm ± 4.0 with an average tumor dose of 173 Gy ± 109. The average dose to the nontumor parenchyma within the target volume was 93.4 Gy ± 32.6, with on average 50% of the parenchymal voxels receiving > 79 Gy ± 23 and 10% receiving > 173 Gy ± 55. The average and median tumor-to-parenchymal weighted dose ratios were 2.2 and 1.9, respectively., Conclusions: Using recommended dosimetry and administration techniques for lobar glass microsphere radioembolization, high doses to target tumors as well as background parenchyma were achieved on average with modest preferential uptake within tumors. There was wide variation in measured tumor and parenchymal doses after hepatic radioembolization for HCC, suggesting the need for continued development of patient-specific dosimetry., (Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the safety and effectiveness of the retrievable Option inferior vena cava (IVC) filter in patients at risk for pulmonary embolism (PE)., Materials and Methods: This was a prospective, multicenter, single-arm clinical trial. Subjects (N = 100) underwent implantation of the IVC filter and were followed for 180 days; subjects whose filters were later removed were followed for 30 days thereafter. The primary objective was to determine whether the one-sided lower limit of the 95% CI for the observed clinical success rate was at least 80%. Clinical success was defined as technical success (deployment of the filter such that it was judged suitable for mechanical protection from PE) without subsequent PE, significant filter migration or embolization, symptomatic caval thrombosis, or other complications., Results: Technical success was achieved in 100% of subjects. There were eight cases of recurrent PE, two cases of filter migration (23 mm), and three cases of symptomatic caval occlusion/thrombosis (one in a subject who also experienced filter migration). No filter embolization or fracture occurred. Clinical success was achieved in 88% of subjects; the one-sided lower limit of the 95% CI was 81%. Retrieval was successful at a mean of 67.1 days after implantation (range, 1-175 d) for 36 of 39 subjects (92.3%). All deaths (n = 17) and deep vein thromboses (n = 18) were judged to have resulted from preexisting or intercurrent illnesses or interventions and unrelated to the filter device; all deaths were judged to be unrelated to PE., Conclusions: Placement and retrieval of the Option IVC filter were performed safely and with high rates of clinical success., (Copyright (c) 2010 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: Many patients undergo placement of tunneled cuffed central venous catheters (TCCVCs) for indications including administration of medical therapy and hemodialysis. They are removed when no longer needed or if there is a device complication. There is no consensus regarding the necessity of routine preremoval coagulation studies or platelet count, so this study was performed to determine if abnormal coagulation status affects the time to hemostasis (TH) after traction removal of TCCVCs., Materials and Methods: Adult patients referred to our group for removal of a TCCVC placed via a jugular or subclavian route were considered candidates for inclusion. Blood was submitted for evaluation of prothrombin time (PT) and International Normalized Ratio (INR), activated partial thromboplastin time (aPTT), and platelet count. Catheters were removed with the traction technique, and presence of hemostasis was assessed at 5-minute intervals of manual compression., Results: Between November 19, 2001, and April 20, 2004, 179 subjects were enrolled and completed the study. There were 165 subjects in whom TH was within the first 5-minute interval and 14 in whom more than 5 minutes was required. Statistically significant factors associated with prolonged TH were primary diagnosis of end-stage renal disease (P = .005), use of antiplatelet agents (P = .03), and procedure performed by a "low-volume" operator (P = .002)., Conclusions: Routine preremoval evaluation of coagulation parameters is not necessary. Patients who are likely to have abnormal platelet function but not abnormal platelet number appear to be at risk for prolonged TH, but even in those cases, the THs are rarely more than 15 minutes.

For many years, available anticoagulant medications were limited to vitamin K antagonists, unfractionated heparin, and aspirin. However, in the past 20 years, several new agents have been developed for the treatment of thrombosis, and even more are being developed. This increasing number of medications has led to more specific treatment algorithms for the care of venous and arterial thrombotic events. As more agents become available, treatment guidelines are rapidly changing. With increasing frequency, interventional radiologists encounter patients already taking anticoagulant medications prophylactically or therapeutically, or they need to determine which anticoagulant medications need to be initiated for a particular procedure. Therefore, it has become increasingly important to understand the mechanisms, risks, and benefits of anticoagulant medications. A review of the traditional anticoagulants, their new counterparts, and their places in the medication repertoire of interventional radiology will be discussed herein.

Interventional radiology (IR) is a clinical subspecialty; as such, there is a large amount of direct patient care. However, until recently, this topic has not been a major focus in radiology training programs. Additionally, as interventional radiologists develop busier and busier practices, there is less time to spend with individual patients. Physician extenders such as physician assistants (PAs) represent an excellent way to improve clinical patient care. This article describes what PAs are and how they work together with physicians. It illustrates differences between PAs and other physician extenders and describes the duties that may be delegated to PAs in the IR setting.

Purpose: Currently available 4-F and 5-F peripherally inserted central catheters (PICCs) were investigated to evaluate their possible application for contrast medium injection using power injectors. The study was performed using an in vitro model to demonstrate the feasibility of using PICCs for contrast-enhanced diagnostic studies., Materials and Methods: An evaluation of 24 catheter versions consisting of 4-F single-lumen and 5-F dual-lumen PICCs from 13 different manufacturers was conducted. Six of the catheter types were silicone and 18 catheter types were polyurethane. Ten catheters of each type were evaluated with five at full length and five trimmed to 40 cm. With use of a silicone-based simulated SVC model, the catheters were infused with 50 mL of intravenous contrast medium at each flow rate increment. Catheters were tested at increasing flow rates from 0.5 to 5 mL/sec in 0.5-mL/sec increments using a Percupump CT injector. Catheters that failed to rupture were then infused at 1-mL/sec increments at flow rates from 5 to 17 mL/sec using a MedRad Mark V power injector. Tolerated and bursting pressures were recorded as well as the location of the catheter rupture., Results: Polyurethane catheters ruptured at flow rates between 4 and 15.4 mL/sec, with one catheter not rupturing at the maximal flow rate (17 mL/sec). Silicone catheters ruptured at flow rates between 0.5 to 3.5 mL/sec. Average rupture locations by type and length were at the extension leg/hub connection area on five of the PICCs, on the extension legs on 21 of the PICCs, on the catheter/hub connection on four PICCs, and on the proximal catheter on 16 of the PICCs., Conclusion: The low burst rates at which all silicone catheters ruptured suggest that those catheters are not able to withstand typical flow rates used for CT arteriography. Conversely, although there is a wide range of discrepancy in the polyurethane catheter burst pressures, many polyurethane catheters can tolerate relatively high flow rates without rupture. This suggests that they may be safely used for CT arteriography with appropriate precautions and protocols in place.

Thirteen patients underwent placement of a balloon-expandable stent either at initial transjugular intrahepatic portosystemic shunt (TIPS) creation (n = 3) because of immediate technical failure of the Wallstent or at shunt revision because of failure of the Wallstent to reduce the portosystemic gradient

In this article, a patient with extensive cerebrovascular disease who had previously undergone bilateral carotid endarterectomy and subsequent operative revision on the left side is described. The patient developed critical restenosis at the cephalic end of the previous left patch angioplasty as well as a severe stenosis of the left common carotid artery origin, which originated from a bovine aortic arch configuration. His right common and internal carotid arteries had become occluded. Endovascular treatment with two metallic stents was successfully performed through a surgical cutdown on the immediate supraclavicular portion of the left common carotid artery to establish antegrade and subsequently retrograde vascular access.

Venous thromboembolic disease (VTD), comprising venous thrombosis and pulmonary embolus, is responsible for innumerable deaths every day. Wide variance in its presentation and clinical manifestations and the resultant difficulties in achieving its diagnosis have confounded attempts to define optimal diagnostic and treatment strategies. Those strategies should be predicated on the understanding of the manifestations of VTD and of the attributes and interrelationship of the various modalities available for its diagnosis. This review will present an overview of the literature describing those modalities, their strengths and deficiencies, and their current value in algorithms for the diagnosis of VTD.

Purpose: To determine (i) whether there is a significant increase in hepatic artery blood flow (HABF) after transjugular intrahepatic portosystemic shunt (TIPS) creation and (ii) whether the extent of incremental increase in HABF is predictive of clinical outcome after TIPS creation., Materials and Methods: Prospective, nonrandomized, nonblinded duplex Doppler ultrasound (US) examinations were performed on 24 consecutive patients (19 men; Child Class A/B/C: 4/12/8, respectively) with a mean age of 52.8 years who were referred for TIPS creation for variceal bleeding. Peak hepatic artery velocity and vessel dimensions were used to calculate the hepatic arterial blood flow (HABF) before and after TIPS creation. Patients were clinically followed in the gastrohepatology clinic and TIPS US surveillance was performed at 1 and 3 months to assess shunt function. The extent of incremental increase in HABF was analyzed as a predictor of post-TIPS encephalopathy and/or death., Results: The technical success rate of TIPS creation was 100%. The shunt diameters were either 10 mm (n = 11) or 12 mm (n = 13). TIPS resulted in a significant reduction in the portosystemic gradient from 24.3 mm Hg +/- 5.7 to 9.3 mm Hg +/- 2.9 (P <.001). The hepatic artery peak systolic velocity and HABF increased significantly after TIPS creation, from 60.8 cm/sec +/- 26.7 to 121 cm/sec +/- 51.5 (P <.001) and from 254.2 mL/min +/- 142.2 to 507.8 mL/min +/- 261.3 (P <.001), respectively. The average incremental increase in HABF from pre-TIPS to post-TIPS was 253.6 mL/min +/- 174.2 and the average decremental decrease in portosystemic gradient was 15.0 mm Hg +/- 5.3, but there was no significant correlation (r = 0.04; P =.86) between the two. All shunts were patent at 30 and 90 days without sonographic evidence of shunt dysfunction. After TIPS creation, new or worsened encephalopathy developed in five patients at 30 days and in an additional three at 90 days. They were all successfully managed medically. Three patients (12.5%) died within 30 days of the TIPS procedure. The extent of incremental increase in HABF after TIPS was variable and did not correlate with the development of 30-day and 90-day encephalopathy (P =.41 and P =.83, respectively) or 30-day mortality (P =.2)., Conclusions: HABF increases significantly after TIPS but is not predictive of clinical outcome. The significance of the incremental increase is yet to be determined.

Purpose: To create a porcine hemodialysis access model that reliably reproduces intimal hyperplasia (IH) of the outflow vein similar to that which causes access failure in human patients undergoing dialysis treatments., Materials and Methods: Surgical technique for creation of side-to-side iliac-artery-to-ipsilateral-iliac-vein (IAV) native fistulas and IAV conduits was optimized in three standard-bred pigs. Persistent patency of fistulas and conduits was demonstrated in two additional pigs allowed to survive for 1 week. IAV fistulas and contralateral 2-cm polytetrafluoroethylene IAV conduits were created in five additional pigs. Venous outflow from these fistulas and conduits was evaluated with venography and intravascular ultrasound (IVUS) immediately after creation (day 0) and at 2-week intervals for as long as 64 days. Animals were killed at 30 days (n = 1), 42 days (n = 2), or 64 days (n = 2), and the arteries, veins, and conduits were evaluated histologically., Results: IAV native fistulas remained patent until the animals' death and conduits remained patent for at least 14 days in four of five pigs; both the fistula and conduit likely occluded before 16-day follow-up in the fifth pig. At 42-64 days, venography demonstrated maximum fistula outflow vein diameter stenoses of 53%-76% and maximum conduit outflow vein stenoses of 44%-84%, and IVUS demonstrated maximum area stenoses of 64%-86% and 43%-82%, respectively. Three of five conduits occluded, one before 16-day follow-up, one between 14 and 28 days, and the other after 42 days. Histologic sections demonstrated IH predominantly affecting the veins at the anastomoses and central (cephalad) to the anastomoses in all pigs., Conclusion: This porcine model reproduces IH in the fistula or conduit outflow vein with measurable stenosis. Such a model might allow relevant preclinical evaluation of interventional devices and techniques intended to reduce the effects of IH in human patients undergoing dialysis treatments.

Purpose: Injected sodium alginate may be a useful perivascular drug delivery vehicle. This study was performed to determine the release rates of heparin from sodium alginate hydrogels cross-linked with varying amounts of calcium gluconate., Materials and Methods: Six hydrogels, composed of 0.16 mEq sodium alginate and 4,000 units unfractionated heparin, were cross-linked with calcium gluconate to yield ion equivalence (IE) ratios (calcium:alginate) of 0.2, 0.4, 0.58, 0.8, 1.0, or 1.2. Two milliliters of normal saline was placed on top of each gel and allowed to remain in contact for up to 10 days. At set time intervals, the amount of heparin in the eluent was determined with use of high-performance liquid chromatography., Results: Gels with 0.2 and 0.4 IE were partially liquid at 24 hours; the other gels solidified within 10 minutes. The 0.58 IE gel was slowest to solidify but immobilized the most heparin and released heparin slowest over 10 days. At 10 days, between 5.5% and 9.8% of the heparin immobilized was retained in the gel., Conclusion: This hydrogel shows promise as a vehicle for in vivo perivascular heparin delivery. The 0.58:1 IE ratio hydrogel has slowest release rate and the greatest immobilization despite its longer cross-linking time.

Purpose: Precise vessel sizing prior to endovascular intervention is critical to achievement of technical success. Diameter measurements obtained with CO2 and iodinated contrast material in an aortoiliac flow model were compared., Materials and Methods: Aortoiliac flow was simulated in a compliant, silicone elastomer phantom of the aortoiliac system using an autoperfusion pump (flow volume, approximately 1100 mL/min; mean arterial pressure, 70-80 mm Hg at 80-90 cycles/minute) and a glycerol solution (40% by weight; viscosity 3.7 centipoise at 20 degrees C). Digital subtraction angiography was performed with the phantom in the anteroposterior (AP) plane and in three oblique planes with both CO2 and iodinated contrast material. Five sets of images for both CO2 and iodinated contrast material were obtained for each projection. Two readers independently performed vessel diameter measurements at seven sites (distal abdominal aorta, bilateral proximal and distal common iliac, and mid-external iliac arteries). The model was then evaluated with intravascular ultrasound (IVUS) using a 20-MHz imaging catheter. Actual diameter measurements were taken from the inner wall to inner wall in orthogonal planes at the same locations within the model, as described previously. Analysis was performed to determine local difference in measurements (t tests), difference when compared to the standard AP projection with iodinated contrast material (Dunnett's test) and inter-reader variability (Pitman's test)., Results: The contralateral iliac vessel segment did not opacify when imaging with CO2 in the 45 degrees obliquities; thus, 22 of 28 sites were available for comparison. At 18 of 22 (81.8%) sites, there was significant difference in vessel measurements (P < .01), with CO2 yielding a significantly larger diameter at 17 of 22 (77.3%) of the sites. The difference in mean diameter ranged from -1.28 to 4.47 mm. With use of the AP iodinated contrast material run as the standard, there were significant differences (P < .05) in vessel diameter at 17 of 22 (77.3%) and four of 21 (19%) sites for CO2 and iodinated contrast material respectively, with CO2 tending toward greater diameter measurements. Significant differences (P < .05) in variance between the two readers were present but occurred primarily with CO2 in the AP projection and iodinated contrast material in the 45 degrees left obliquity. With use of IVUS as the standard, there were significant differences (P < .05) in the measured vessel diameters with CO2 at nine of 22 (40.9%) of the sites and with iodinated contrast material at 17 of 28 (60.7%) of the sites. Of the measurements made with CO2, seven of nine (77.8%) of the measurements were of larger diameter than those obtained with IVUS. By contrast, of the measurements made with iodinated contrast material angiography, IVUS measured larger diameters in 16 of 17 (94.1%)., Conclusion: CO2 angiography consistently yielded significantly larger vessel measurements when compared to both iodinated contrast angiography and WVUS. These results have important implications in regards to planning intervention based solely on CO2 angiography. Further evaluation is needed before recommending CO2 for vessel sizing in clinical practice.

Purpose: To assess the feasibility of intravascular delivery of nadroparin, a low-molecular-weight heparin, via hydrogel-coated angioplasty balloons, and the effects of nadroparin delivered in this manner on platelet deposition and smooth muscle cell (SMC) proliferation., Materials and Methods: Tritiated nadroparin was used to determine the nadroparin-carrying capacity of the hydrogel-coating, kinetics of release from the balloons, and, in four pigs, delivery of the nadroparin to the iliac arterial wall. Platelet deposition in nadroparin-treated iliac arteries versus contralateral iliac arteries dilated with saline-loaded, hydrogel-coated balloons was quantified in seven pigs using 111Indium-labeled platelets. Smooth muscle cell proliferation in nadroparin and saline-treated iliac arteries in 10 pigs was evaluated 7 days after angioplasty with use of proliferating cell nuclear antigen., Results: Approximately 98 international units of nadroparin were delivered by the hydrogel-coated balloon, the majority to the angioplasty site and distal vessel. There was a trend toward decreased platelet deposition in nadroparin-treated arteries, but statistical significance was not achieved (P = .1563). Medial SMC proliferation was decreased in the nadroparin-treated arteries in nine of 10 pigs (P = .0137)., Conclusions: Hydrogel-coated balloons may be used to deliver nadroparin to the arterial wall, with measurable levels of the drug delivered to the site of angioplasty, and with resultant decrease in SMC proliferation.

Purpose: Successful deployment of an endoluminal prosthesis for repair of an abdominal aortic aneurysm (AAA) is critically dependent on accurate preoperative assessment of aneurysm morphology with use of such modalities as contrast aortography (CA), spiral computed tomography (CT), magnetic resonance (MR) imaging, and intravascular ultrasonography (IVUWS). The authors describe a new phantom that could be used both to calibrate these four imaging modalities and to determine which imaging technique(s) is (are) best for preoperative AAA sizing., Materials and Methods: A life-sized AAA model was constructed of silicone elastomers with luminal access ports for introduction of contrast media and catheters. Contrast material-filled rings were positioned circumferentially along the length of the model as reference points for dimension measurements. The modalities were compared to each other relative to the actual dimensions of the model, as determined at its construction., Results: In this pilot study, all modalities were relatively similar in their ability to measure the dimensions of the AAA model. Length measurements accounted for most of the interinstitutional and interobserver variability. MR imaging had the least variability., Conclusions: The authors developed a new phantom that can be imaged successfully with CA, CT, MR imaging, and IVUS in repetitive, reproducible fashion. Structural refinements and future larger scale, statistically significant evaluations of such models should establish this as a useful adjunct in multicenter endoluminal stent-graft trials to allow calibration of imaging modalities and to determine which modality or modalities is (are) best for preoperative AAA sizing.

Purpose: To determine whether intraarterial digital subtraction arteriography (DSA) is as sensitive and specific as cut film arteriography (CFA) in the evaluation of suspected aortic injury resulting from blunt chest trauma., Materials and Methods: Both CFA and DSA images of the thoracic aorta were obtained in the right posterior oblique (RPO) projection in 100 of 103 consecutive patients undergoing arteriography after blunt chest trauma. Diagnoses based on blinded separate review of both studies (CFA vs DSA) by four independent reviewers were compared. Reviewers graded their confidence in their diagnoses from 1 (certain) to 10 (uncertain)., Results: Eleven of 100 patients had aortic or great vessel injuries confirmed by operation (n = 10) or transesophageal echocardiography (n = 1). Three hundred eighty-eight of 400 diagnoses based on RPO CFA and 390 of 400 diagnoses based on RPO DSA agreed with the correct diagnoses. The sensitivity, specificity, and diagnostic accuracy of CFA versus DSA were not significantly different. The reviewers' confidence in their diagnoses was equivalent between CFA (average confidence score, 1.373) and DSA (average confidence score, 1.375)., Conclusion: DSA and CFA yield equivalent sensitivity, specificity, and diagnostic accuracy in the evaluation of blunt chest trauma.

Purpose: To determine the incidence and significance of arterial emboli resulting from surgical thrombectomy/revision of hemodialysis grafts. This information may help in determining the significance and management of similar emboli resulting from percutaneous hemodialysis graft thrombolysis., Patients and Methods: Patients undergoing surgical thrombectomy/revision of clotted hemodialysis grafts are studied with postoperative fistulography per institutional protocol whenever possible. For this retrospective study, all postoperative fistulograms from a 1-year period were reviewed for the presence of arterial emboli. Patients with documented arterial emboli were examined for evidence of hand/digital ischemia; only those patients with signs or symptoms of ischemia were treated. At clinical follow-up, repeated evaluation for hand/digital ischemia was performed., Results: Ninety-one thrombectomy/revision procedures were performed during the study period. Postoperative fistulograms were obtained after 67 of these procedures in 32 patients. One patient complained of hand pain during dialysis prior to acquisition of the postoperative fistulogram. Arterial emboli were documented in eight patients (12%; brachial, n = 3; radial, n = 2; ulnar, n = 2; radial/ulnar, n = 1). The single symptomatic brachial embolus was percutaneously removed; no intervention was undertaken in the remainder. At mean follow-up of 14 months, no patient had developed hand or digital ischemia. Subsequent fistulograms demonstrated partial (n = 2) or complete (n = 2) resolution of the untreated emboli., Conclusion: Arterial emboli are a relatively common occurrence with surgical thrombectomy/revision. Conservative management appears to be indicated in asymptomatic patients.

Purpose: To determine the accuracy of two-dimensional (2D) time-of-flight (TOF) magnetic resonance (MR) angiography, performed with state-of-the-art equipment, in the evaluation of the iliac arteries., Materials and Methods: The iliac arteries of 50 patients undergoing conventional arteriography for evaluation of lower-extremity ischemia or abdominal aortic aneurysm were also imaged with axial 2D TOF MR angiography. Blinded interpretations of conventional arteriograms and MR angiograms were compared. MR angiography was performed with a 1.5-T system with 2-mm contiguous axial sections, 60 degrees flip angle, 28-msec repetition time, and 7.4-msec echo time., Results: Blinded interpretations of 2D TOF MR angiograms matched those of conventional arteriograms in 26 of 50 patients (52%). For the diagnosis of obstructive iliac artery lesions, sensitivity and specificity with MR angiography were 85% and 59%, respectively. Two of three saccular iliac artery aneurysms escaped detection with MR angiography., Conclusion: Iliac artery evaluation with axial 2D TOF MR angiography is not sufficiently accurate to warrant its use as a replacement for conventional arteriography in patients who lack contraindications to the latter.

Purpose: To determine the frequency with which treatment plans based on findings at magnetic resonance angiography (MRA) match those based on findings at conventional x-ray arteriography (XRA) in the evaluation of symptomatic lower extremity ischemia., Patients and Methods: Two-dimensional time-of-flight (TOF) MRA was performed in 42 patients undergoing XRA for evaluation of symptomatic lower extremity ischemia. The blind interpretations and treatment plans based on MRA findings were compared with those based on XRA findings, with use of XRA as the standard of reference., Results: For identification of hemodynamically significant stenosis or occlusion, the sensitivity and specificity of MRA was 100% and 23% for iliac segments, 100% and 82% for common femoral segments, 89% and 67% for superficial femoral segments, 100% and 88% for popliteal segments, and 92% and 91% for tibioperoneal segments, respectively. The treatment plan based on MRA findings matched that based on XRA findings in 41% of patients., Conclusion: For evaluation of symptomatic lower extremity ischemia, two-dimensional TOF MRA cannot be considered a reliable substitute for XRA in patients who lack contraindications to XRA.