Anatomical Variations of the Left Adrenal Vein Encountered During Venous Sampling

PurposeTo identify anatomical variations in the left adrenal vein (LAV) and to evaluate the role of preprocedural contrast-enhanced computed tomography (CT) planning.MethodsThe length of the left adrenal central vein (LACV), the vessel that receives blood from all tributaries of the left adrenal gland, was measured using venograms of patients who had undergone adrenal venous sampling (AVS) for the diagnosis of primary aldosteronism between October 2017 and December 2019. The anatomical variants of the LAV were described and classified. Contrast-enhanced CT was used to evaluate the detection rate of the following: (a) confluence of the left inferior phrenic vein and the LAV and (b) the last tributary flowing into the LAV.ResultsIn total, 311 patients (143 men, 168 women; mean age: 49.3 years ± 11.0) were enrolled. Of them, 9 (2.9%) patients had anatomical variants lacking a LACV. In patients with a LACV (n = 302), the venographic LACV length was 9.0 mm ± 3.9 (<1 mm in 9 patients). The detection rate of the confluence of the left inferior phrenic vein and LAV, as determined using contrast-enhanced CT, was high (96.2%), whereas that of the last tributary flowing into the LAV was low (0.8%). In 4 of 18 patients with short or absent LACV, the variant was visualized using contrast-enhanced CT.ConclusionsIn some patients, the LACV is absent or short, which is an anatomical variation. Understanding venographic anatomical variations can help avoid misleading results resulting from a suboptimal sampling site in AVS. For some subtypes, contrast-enhanced CT may also help in planning the AVS procedure.     

Intravascular Ultrasound-Guided Transvenous Biopsy of Retroperitoneal Lymph Nodes: Diagnostic Accuracy and Safety Compared with CT-Guided Percutaneous Biopsy

PurposeTo compare the diagnostic accuracy and adverse event rates of intravascular ultrasound (US)-guided transvenous biopsy (TVB) versus those of computed tomography (CT)-guided percutaneous needle biopsy (PNB) for retroperitoneal (RP) lymph nodes.Materials and MethodsIn this single-institution, retrospective study, 32 intravascular US-guided TVB procedures and a sample of 34 CT-guided PNB procedures for RP lymph nodes where targets were deemed amenable to intravascular US-guided TVB were analyzed. Procedural metrics, including diagnostic accuracy, defined as diagnostic of malignancy or a clinically verifiable benign result, and adverse event rates were compared.ResultsThe targets of intravascular US-guided TVB were primarily aortocaval (47%, 15/32) or precaval (34%, 11/32), whereas those of CT-guided PNB were primarily right pericaval (44%, 15/34) or retrocaval (44%, 15/34) (P < .001). The targets of intravascular US-guided TVB averaged 2.4 cm in the long axis (range, 1.3–3.7 cm) compared with 2.9 cm (range, 1.4–5.7 cm) for those of CT-guided PNB (P = .02). There was no difference in the average number of needle passes (3.8 for intravascular US-guided TVB vs 3.9 for CT-guided PNB; P = .68). The diagnostic accuracy was 94% (30/32) and the adverse event rate was 3.1% (1/32) for intravascular US-guided TVB, similar to those of CT-guided PNB (accuracy, 91% [31/34]; adverse event rate, 2.9% [1/34]).ConclusionsIntravascular US-guided TVB had a diagnostic accuracy and adverse event rate similar to CT-guided PNB for RP lymph nodes, indicating that intravascular US-guided TVB may be as safe and effective as conventional biopsy approaches for appropriately selected targets.     

Cryoablation of Venous Malformations: A Systematic Review

This study aimed to review systematically the efficacy, safety, and technical aspects of cryoablation in the treatment of venous malformations (VMs) and to provide the groundwork for future studies. A literature search for clinical studies utilizing percutaneous cryoablation of VMs was performed. All clinical studies related to primary or secondary treatment of VMs with percutaneous cryoablation were included in this review. These selected studies were evaluated for patient characteristics, cryoablation technique, technical success, lesion size and pain scores before and after cryoablation, and adverse outcomes. Random effects analysis of postprocedural changes in lesion volume and pain scores was performed. There were 54 patients with 55 cases of cryoablation of VMs. Of these cases, 27 recorded changes in lesion volume and 31 recorded changes in pain scores. The weighted mean postprocedural decrease in lesion size was 92.0% (raw average, 71.7%). The weighted mean reduction in pain score was 77% (raw average, 78.2%). Considering all treated cases (55), complete resolution of symptoms was seen in 35 cases (63.6%) and overall (complete or partial) improvement in 52 cases (94.5%). Common postprocedural symptoms included pain, bruising, swelling and numbness lasting less than 2 weeks. There were two major adverse events (3.7%), with both cases due to persistent dysesthesia. Patients with a history of prior sclerotherapy demonstrated lower preprocedural and postprocedural pain scores (4.7 and 1.3) than patients without prior treatments (5.8 and 2.8). Cryoablation of VMs appears to be potentially safe and effective on limited short-interval follow-up.     

“Double-Down” Adrenal Vein Sampling Results in Patients with Apparent Bilateral Aldosterone Suppression: Utility of Repeat Sampling including Super-Selective Sampling

PurposeTo report outcomes of patients undergoing adrenal vein sampling (AVS) for primary aldosteronism with results indicating apparent bilateral adrenal suppression (ABAS), in which the adrenal aldosterone-to-cortisol ratios are decreased bilaterally (“double-down”) compared to the non-adrenal sample, and evaluate repeat AVS results.Materials and MethodsBetween 2003 and 2020, 762 patients underwent AVS. Twenty patients (2.6%; male, 12; female, 8; age 50.3 ± 9.7 years) with ABAS on initial AVS were identified. Ten underwent repeat AVS. Super-selective AVS (SS-AVS) was employed in 6 of 10 repeat AVS (60%). Outcomes after AVS were analyzed. A lateralization index (LI) >4 was considered an indication for adrenalectomy.ResultsRepeat AVS was diagnostic in 70% of patients (n = 7), with 6 of 7 lateralizing with LI >4 (median LI = 32.3; range 4.6–54.8) and 1 of 7 nearly lateralizing (LI = 3.5). All 7 patients underwent adrenalectomy. ABAS was redemonstrated in 3 patients (30%): 2 with unilateral adenomas on cross-sectional imaging underwent adrenalectomy despite ABAS results and 1 was lost to follow-up. Four of 6 patients (66%) who underwent SS-AVS were diagnosed with unilateral disease (median LI = 43.3; range 23.9–54.8), with one patient’s diagnosis reliant upon a single super-selective sample. In total, 9 patients underwent adrenalectomy after repeat AVS, all of whom had improved blood pressure control postoperatively. Ten patients did not undergo repeat AVS: 6 were lost to follow-up, 3 underwent medical management, and 1 underwent adrenalectomy.ConclusionsAVS should be repeated when “double-down” ABAS results are encountered. Super-selective sampling may provide worthwhile diagnostic data when employed during repeat AVS.     

Transjugular Renal Biopsy Bleeding Risk and Diagnostic Yield: A Systematic Review

This study aimed to better define the safety and efficacy of transjugular renal biopsy (TJRB) based on published studies. Seventeen published articles were included (1,321 biopsies). Complications were classified as major if they resulted in blood transfusion or additional invasive procedures. All other bleeding complications were considered minor. Diagnostic tissue was obtained in 1,193 procedures (90.3%). The total incidence of bleeding complications among 15 articles with complete data was 202 of 892 procedures (22.6%): 162 (18.2%) minor and 40 (4.5 %) major. These results show that TJRB is a feasible procedure for obtaining renal tissue for diagnosis and that most complications are self-limiting.     

Transjugular versus Transfemoral Transcaval Liver Biopsy: A Single-Center Experience in 500 Cases

PurposeTo compare the safety and efficacy of transfemoral transcaval liver biopsies (TFTC) with that of transjugular liver biopsies (TJLB) at a single tertiary-care institution.Materials and MethodsA retrospective review was performed of 500 consecutive transvenous liver biopsies between December 2010 and December 2018. The cases included 286 TFTC patients at a median age of 54 years old (interquartile range [IQR], 42–63 years of age), 37.4% were female; and 214 TJLB patients at a median age of 55 years old (IQR, 46–61 years of age), 45.4% female. Patient demographic and laboratory data and technical and histopathological success, fluoroscopy times, and complications were recorded. Comparative statistical analyses were performed using a 2-sample test or a Wilcoxon ranked sum test for continuous variables and a chi-square test or Fisher exact test for categorical variables when appropriate.ResultsTFTC and TJLB data are presented as: technical success rates of 99.3% (283 of 286) and 100% (214 of 214), respectively; histopathologic success rates of 96.5% (275 of 285) and 95.8% (205 of 214), respectively; and major complication rates of 1.4% (4 of 284) and 5.6% (12 of 214), respectively (P = .009). There were no hepatic injuries in the TFTC group, whereas the TJLB group included 6 significant hepatic injuries requiring intervention. Median fluoroscopic times were 5.5 minutes (IQR, 3.9–8.6 minutes) for TFTC and 8.1 minutes (IQR, 5.2–13.1) for TJLB (P < .001).ConclusionsIn this single-institution study, TFTC was associated with a lower major complication rate and lower fluoroscopy times than conventional TJLB with similar technical and histopathologic successes.     

Intravascular Ultrasound-Guided Transvenous Biopsy of Abdominal and Pelvic Targets Difficult to Access by Percutaneous Needle Biopsy: Technique and Initial Clinical Experience

PurposeTo report initial clinical experience with intravascular ultrasound (US)-guided transvenous biopsy (TVB) for perivascular target lesions in the abdomen and pelvis using side-viewing phased-array intracardiac echocardiography catheters.Materials and MethodsIn this single-institution, retrospective study, 48 patients underwent 50 intravascular US-guided TVB procedures for targets close to the inferior vena cava or iliac veins deemed difficult to access by conventional percutaneous needle biopsy (PNB). In all procedures, side-viewing phased-array intracardiac echocardiography intravascular US catheters and transjugular liver biopsy sets were inserted through separate jugular or femoral vein access sheaths, and 18-gauge core needle biopsy specimens were obtained under real-time intravascular US guidance. Diagnostic yield, diagnostic accuracy, and complications were analyzed.ResultsIntravascular US-guided TVB was diagnostic of malignancy in 40 of 50 procedures for a diagnostic yield of 80%. There were 5 procedures in which biopsy was correctly negative for malignancy, with a per-procedure diagnostic accuracy of 90% (45/50). Among the 5 false negatives, 2 patients underwent repeat intravascular US-guided TVB, which was diagnostic of malignancy for a per-patient diagnostic accuracy of 94% (45/48). There were 1 (2%) mild, 2 (4%) moderate, and 1 (2%) severe adverse events, with 1 moderate severity adverse event (venous thrombosis) directly attributable to the intravascular US-guided TVB technique.ConclusionsIntravascular US-guided TVB performed on difficult-to-approach perivascular targets in the abdomen and pelvis resulted in a high diagnostic accuracy, similar to accepted thresholds for PNB. Complication rates may be slightly higher but should be weighed relative to the risks of difficult PNB, surgical biopsy, or clinical management without biopsy.     

Research Priorities in Pelvic Venous Disorders in Women: Recommendations from a Multidisciplinary Research Consensus Panel

Pelvic venous disorders (PeVDs) in women can present with chronic pelvic pain, lower-extremity and vulvar varicosities, lower-extremity swelling and pain, and left-flank pain and hematuria. Multiple evidence gaps exist related to PeVDs with the consequence that nonvascular specialists rarely consider the diagnosis. Recognizing this, the Society of Interventional Radiology Foundation funded a Research Consensus Panel to prioritize a research agenda to address these gaps. This paper presents the proceedings and recommendations from that Panel.     

Percutaneous Image-Guided Core Needle Biopsy of Neuroendocrine Tumors: How Common Is Intraprocedural Carcinoid Crisis?

PurposeTo retrospectively evaluate the incidence of carcinoid crisis, other complications, and physiologic disturbances during percutaneous image-guided core needle biopsy of neuroendocrine tumors (NETs) in the lung and the liver.Materials and MethodsBetween January 2010 and January 2020, 106 computed tomography (CT) or ultrasound (US)-guided core needle biopsies of lung and liver NETs were performed in 95 consecutive adult patients. The mean age was 64 ± 13 years, and 48% were female. The small bowel was the most common primary site (33%, 31/95), and 32 (34%) patients had pre-existing symptoms of carcinoid syndrome. The mean tumor size was 3.2 ± 2.6 cm, and mean number of passes was 3.4 ± 1.6. A 17/18-gauge needle was used in 91% (96/106) of the biopsies. Thirteen (12%) patients received either outpatient or prophylactic octreotide.ResultsNo patients experienced carcinoid crisis or needed octreotide, inotropes, vasopressors, or resuscitation. A single biopsy procedure (0.9%, 1/106) was complicated by bleeding that required angiographic hepatic artery embolization. Changes in pre-biopsy- versus post-biopsy systolic blood pressure and heart rate were -1.6 mm Hg (P = .390) and 0.6 beat/min (P = .431), respectively. Tumor functional status, overall tumor burden, and the elevation of neuroendocrine markers were not associated with intraprocedural physiologic disturbances. There were 4 minor complications (0.4%, 4/106) associated with the biopsy procedure that were not attributed to hormone excretion from tumor manipulation.ConclusionsPercutaneous image-guided core biopsy of NETs is safe, with low complication rate and no definite carcinoid crisis in the current cohort.     

Transtail Artery Access in Rats: A New Technique for Repeatable Selective Angiography

Transtail artery approach successfully enables selective arterial catheterization and angiography in the rat. This technique is effective and repeatable. In addition to its utility in imaging, it may also have a wide range of applications in transcatheter therapy and experimental cerebral stroke models.     

Infected Extrahepatic Splanchnic Venous Stent(-Grafts): Clinical Presentation,Imaging, and Treatment in Three Patients

This brief report describes 3 patients with infected extrahepatic splanchnic venous stents or stent grafts. These devices had been placed to treat prehepatic portal hypertension 4 wk, 3 mo, and 31 mo, respectively, before readmission for fever. Blood cultures and fluorine-18 fludeoxyglucose positron emission tomography/CT were positive in all. With systemic antibiotic treatment, 2 patients showed a clinical recovery. In the third patient, antibiotic treatment failed. Therefore, the infected stent graft was surgically removed and a splenorenal shunt was created. No recurrent splanchnic venous infection was observed in these 3 patients.     

Percutaneous Lung Biopsy with Pleural and Parenchymal Blood Patching: Results and Complications from 1,112 Core Biopsies

PurposeTo evaluate the outcomes of computed tomography (CT) fluoroscopy-guided core lung biopsies with emphasis on diagnostic yield, complications, and efficacy of parenchymal and pleural blood patching to avoid chest tube placement.MethodsThis is a single-center retrospective analysis of CT fluoroscopy-guided percutaneous core lung biopsies between 2006 and 2020. Parenchymal blood patching during introducer needle withdrawal was performed in 74% of cases as a preventive measure, and pleural blood patching was the primary salvage maneuver for symptomatic or growing pneumothorax in 60 of 83 (72.2%) applicable cases.ResultsA total of 1,029 patients underwent 1,112 biopsies (532 men; mean age, 66 years; 38.6%, history of emphysema; lesion size, 16.7 mm). The diagnostic yield was 93.6% (1,032/1,103). Fewer complications requiring intervention were observed in patients who underwent parenchymal blood patching (5.7% vs 14.2%, P < .001). Further intervention was required in 83 of 182 pneumothorax cases, which included the following: (a) pleural blood patch (5.4%, 60/1,112), (b) chest tube placement without a pleural blood patch attempt (1.5%, 17/1,112), and (c) simple aspiration (0.5%, 6/1,112). Pleural blood patch as monotherapy was successful in 83.3% (50/60) of cases without need for further intervention. The overall chest tube rate was 2.6% (29/1,112). Emphysema was the only significant risk factor for complications requiring intervention (P ≤ .001).ConclusionsParenchymal blood patching during introducer needle withdrawal decreased complications requiring intervention. Salvage pleural blood patching reduced the frequency of chest tube placement for pneumothorax.     

Endovascular Therapy for Vasculogenic Erectile Dysfunction: A Systematic Review and Meta-Analysis of Arterial and Venous Therapies

PurposeTo systematically review and perform a meta-analysis on the safety and efficacy of endovascular therapy in the treatment of the two most common etiologies of vasculogenic erectile dysfunction (ED): veno-occlusive dysfunction (VOD) and arterial insufficiency (AI).Materials and MethodsPubMed, Web of Science, ScienceDirect, and Scopus databases were searched for published English literature regarding endovascular ED treatments. Case series (n ≥ 3) were included. Multiple data points were obtained, including demographic data, etiology, diagnosis method, imaging studies, treatment approach, technical success, clinical success, complications, and follow-up.ResultsSixteen relevant articles were obtained and a total of 212 patients with VOD and 162 with AI were identified. The VOD cohort were treated either percutaneously (60.4%; n = 128) or after surgical exposure of the deep dorsal vein (33.5%, n = 71), or it was unspecified (6.1%; n = 13). The most common embolic used was n-butyl cyanoacrylate (51.9%; n = 109). Meta-analysis found an overall clinical success rate of 59.8% in VOD patients. Complications occurred in 5.2% of patients (n = 11), with 9 considered to be mild and 2 considered to be severe. The AI cohort contained 162 patients most commonly treated via stenting of the internal pudendal artery (40.1%; n = 65). Meta-analysis found an overall clinical success rate of 63.2% in AI patients. Complications occurred in 4.9% of patients (n = 8), with 4 considered to be mild and 4 considered to be severe.ConclusionsEndovascular therapy for medically refractory ED is safe and may provide a treatment alternative to more invasive surgical management; however, conclusions are limited by the heterogeneity of clinical success definitions among the included studies.     

Comparison of Fibered versus Nonfibered Coils for Venous Embolization in an Ovine Model

PurposeTo compare nylon fibered (F) with nonfibered (NF) coils for embolization in an ovine venous model.Materials and MethodsFour- to 8-mm-diameter, 0.035-inch F and NF coils were deployed in 24 veins in 6 sheep. The number of coils, total length of the coils, and length of implanted coil pack required to achieve complete stasis were recorded, as were vessel diameter, radiation dose, ease of packing, damage to embolized vessel, and time to stasis. Venography at 1 and 3 months was used to assess the migration and durability of vessel occlusion. Veins were harvested at 3 months.ResultsF and NF coils were deployed in 24 veins, and stasis was achieved, without immediate coil migration or vessel damage. The mean numbers of F and NF coils per vein were 5 and 8.75, respectively (P = .007). The vessel diameter between the groups was not statistically different. The total coil length (F, 70 cm vs NF, 122.5 cm; P = .0007), coil pack length (F, 29.3 mm vs NF, 39.4 mm; P = .003), time to stasis (F, 5.3 minutes vs NF, 9.0 minutes; P = .008), and radiation dose (F, 25.3 mGy vs NF, 34.9 mGy; P = .037) were significantly different between the groups. Challenges with the animal model prevented conclusive long-term results. Migration occurred with 8 of 11 (72%) coil packs in the femoral veins and 0 of 13 (0%) coil packs in the internal iliac and deep femoral veins. Venography demonstrated that of 16 remaining coil packs, 11 were occluded at 1 month and 10 remained occluded at 3 months.ConclusionsFibers allow for significantly fewer coils to achieve immediate venous occlusion.     

Outcomes of Venoplasty-Assisted,Peripherally Inserted Central Catheter Placement in Patients with Upper-Arm Venous Stenosis: Comparison with Midlines and Contralateral Placement

PurposeTo compare the effectiveness and safety of percutaneous transluminal angioplasty and peripherally inserted central catheter (PTA + PICC), contralateral PICC, and midline catheterization (MC) in patients with venous stenosis.Materials and MethodsA total of 7,327 PICC procedures were performed in 5,421 patients at a single institution between 2013 and 2019. Among them, 87 patients had upper-arm venous stenoses and were managed with PTA + PICC, contralateral PICC, or MC. Data on catheter-dwell time, clinical success rate, and adverse events were recorded. The procedure was considered to have clinically succeeded when a PICC was removed from the patient just before discharge or after the completion of therapy. Catheter survival time and the chance of adverse events were compared among the groups using the Kaplan-Meier method and log-rank test.ResultsPTA + PICC, contralateral PICC, and MC procedures were performed for 57 (65.5%, 57/87), 10 (11.5%, 10/87), and 20 (23.0%, 23/87) patients, respectively. The mean catheter-dwell time in the PTA + PICC, contralateral PICC, and MC groups was 49.7, 28.7, and 15.1 days, respectively, and the clinical success rate of each group was 86.0% (49/57), 80.0% (8/10), and 50.0% (10/20). The PTA + PICC group had a significantly longer catheter survival time than the MC group (P < .001). The chance of a catheter-related infection (P = .008) was significantly lower in the PTA + PICC group than in the MC group.ConclusionsPTA + PICC or contralateral PICC should be considered prior to ipsilateral MC when venous stenosis is encountered during PICC procedures.     

Pelvic Venous Disorders in Women due to Pelvic Varices: Treatment by Embolization: Experience in 520 Patients

PurposeThe purpose of this study was to determine the efficacy and safety of embolization treatment in pelvic venous disorders in women refluxing in the ovarian and or internal iliac veins in women with chronic pelvic pain.Materials and MethodsA retrospective study conducted from January 2000 to June 2017 in 617 patients diagnosed with pelvic venous disorders (PeVDs) with a mean age of 43.2 ± 7.2 years were treated using an embolization procedure. A total of 520 were included, and 97 patients were excluded. The main inclusion criteria were PeVD symptoms for more than 6 months and transvaginal Doppler ultrasonography (TV-DUS) diagnosis of varicose veins in the pelvis with a diameter greater than 6 mm. The main objective was to embolize the 4 main pelvic venous plexi (ovarian and internal iliac veins) whenever possible. Follow-up was performed using clinical symptoms (visual analog scale) and TV-DUS at 1, 3, 6, and 12 months and then every year up to 5 years.ResultsThe technical success (embolization of the 4 main pelvic veins) was achieved in 84.4% of the patients. The average follow-up was 58.7 ± 5.7 months. The visual analog scale was improved from 7.63 ± 0.9 points pretreatment to 0.91 ± 1.5 at 5 years. A total of 26 patients (5%) presented with symptom recurrence and pelvic varicose veins. There were 57 minor complications (10.9%) and 11 major complications (2.1%), with 7 cases (1.34%) of device migration to the lung.ConclusionsThe embolization of pelvic varicose veins is a safe and effective procedure. The selection of the embolic agents and the number of veins needed to be treated.     

The Use of the Transfemoral Transcaval Liver Biopsy Technique for Biopsies of Hepatic Masses

The purpose of this study was to investigate the safety and effectiveness of the transfemoral transcaval (TFTC) liver biopsy technique in patients with hepatic masses with relative contraindications to percutaneous biopsy and/or mass location abutting the inferior vena cava. The medical records of 16 patients (56% men; age range, 21–88 years) who underwent TFTC biopsy of hepatic masses (ranging in diameter from 2.1 to 13.2 cm) from September 2015 to August 2021 were reviewed. Histopathologic diagnoses were made in 15 of 17 (88%) procedures. Two adverse events were noted: worsened preexisting hemobilia requiring embolization in 1 patient, and a decrease in hematocrit level in another patient, requiring only observation. In conclusion, this report showed that the TFTC technique is a relatively safe and effective method for sampling hepatic masses in select cases.     

Venous Biomechanics of Angioplasty and Stent Placement: Implications of the Poisson Effect

PurposeTo characterize the Poisson effect in response to angioplasty and stent placement in veins and identify potential implications for guiding future venous-specific device design.Materials and MethodsIn vivo angioplasty and stent placement were performed in 3 adult swine by using an established venous stenosis model. Iron particle endothelium labeling was performed for real-time fluoroscopic tracking of the vessel wall during intervention. A finite-element computational model of a vessel was created with ADINA software (version 9.5) with arterial and venous biomechanical properties obtained from the literature to compare the response to radial expansion.ResultsIn vivo angioplasty and stent placement in a venous stenosis animal model with iron particle endothelium labeling demonstrated longitudinal foreshortening that correlated with distance from the center of the balloon (R² = 0.87) as well as adjacent segment narrowing that correlated with the increase in diameter of the treated stenotic segment (R² = 0.89). Finite-element computational analysis demonstrated increased Poisson effect in veins relative to arteries (linear regression coefficient slope comparison, arterial slope 0.033, R² = 0.9789; venous slope 0.204, R² = 0.9975; P < .0001) as a result of greater longitudinal Young modulus in veins compared with arteries.ConclusionsClinically observed adjacent segment narrowing during venous angioplasty and stent placement is a result of the Poisson effect, with redistribution of radially applied force to the longitudinal direction. The Poisson effect is increased in veins relative to arteries as a result of unique venous biomechanical properties, which may be relevant to consider in the design of future venous interventional devices.     

A Water-Based Liquid Embolic: Evaluation of its Safety and Efficacy in a Rabbit Kidney Model

PurposeTo evaluate a novel aqueous-based liquid embolic (Embrace Hydrogel Embolic System, [HES]) that has been developed to embolize hypervascular tumors by filling the tumor vascular bed and solidifying into a hydrogel. HES was evaluated for embolization safety and efficacy relative to microspheres in a preclinical rabbit kidney model.Materials and MethodsA renal embolization model in New Zealand white rabbits was utilized. Twenty-four rabbits underwent unilateral kidney embolization via the main renal artery with either HES or 40-μm microspheres. Twenty-two rabbits survived the procedure and were monitored for 2, 12, 17.5, or 26 weeks before sacrifice. All rabbits underwent a repeat renal angiogram before necropsy. HES was evaluated for nontarget embolization, safety, and embolization effectiveness as measured by recanalization and viability of embolized tissue.ResultsBoth embolization materials were found to be safe, with targeted tissue necrosis and absence of nontarget embolization. Prenecropsy angiograms found vascular recanalization in 0/14 (0%) HES-embolized kidneys and in 3/8 (38%) microsphere-embolized kidneys (P = .036). Viable kidney tissue was observed in 2/14 (14%) kidneys embolized with HES and 5/8 (63%) kidneys embolized with microspheres (P = .052). All kidneys embolized with microspheres that showed vascular recanalization had viable tissue on histological sections. HES was observed in vessels as small as 10 μm in diameter in histological analysis.ConclusionsHES provided deep, durable vascular bed embolization that resulted in less recanalization and, on an average, less viable target tissue compared with 40-μm microspheres. No systemic effects or nontarget tissue embolization was identified.