Role of Ultrasound Elastography in Patient Selection for Prostatic Artery Embolization

PurposeTo determine the effects of prostatic artery embolization (PAE) on prostate elasticity as assessed using ultrasound elastography (US-E) and to describe baseline US-E's potential role in patient selection.Materials and MethodsThis was a prospective investigation that included 20 patients undergoing PAE to treat lower urinary tract symptoms attributed to benign prostatic hyperplasia (BPH). US-E with measurement of the prostatic elastic modulus (EM) and shear wave velocity (SWV) was performed before PAE and at 1-month follow-up. Baseline, 3-month, and 1-year follow-up evaluations included prostate-specific antigen, uroflowmetry, pelvic magnetic resonance imaging, and clinical assessment using the International Prostate Symptom Score (IPSS) and quality of life (QoL) metrics.ResultsSeventeen patients entered statistical analysis. US-E showed a significant reduction in mean prostatic EM (34.4 kPa vs 46.3 kPa, −24.7%, P < .0001) and SWV (3.55 m/s vs 4.46 m/s, −20.0%, P < .0001) after PAE. There were moderate positive correlations between baseline EM and 1-year IPSS (R = 0.62, P = .007) and between baseline SWV and 1-year IPSS (R = 0.68, P = .002). Baseline SWV ≥ 5.59 m/s and baseline EM ≥ 50.14 kPa were associated with suboptimal IPSS and QoL outcomes after PAE with high degrees of sensitivity (100%) and specificity (69-100%).ConclusionsPAE led to a positive effect on the BPH dynamic component related to prostatic elasticity. There was a moderate positive correlation between baseline prostatic elastographic parameters and 12-month IPSS. Measurement of baseline elastographic characteristics may become useful for the evaluation and selection of patients for PAE.     

Computed Tomography Angiography Prediction of Successful Trasnscatheter Embolization for Type II Endoleak of Endovascular Abdominal Aortic Aneurysm Repair

PurposeTo evaluate the utility of computed tomography (CT) angiography before transarterial embolization (TAE) in predicting TAE’s technical success for type II endoleaks (T2ELs).Materials and MethodsFifty-eight patients (mean age, 74.4 years; range, 46–89 years) who underwent attempted TAE for T2EL from July 2014 to August 2019 and underwent CT angiography before the procedure were included. Each CT angiography result was assessed for a feeding artery that was traceable over its entire course from either the superior mesenteric artery or the internal iliac artery to the endoleak cavity. TAE was performed using coils and was considered technically successful if embolization of the endoleak cavity and feeding artery was performed. The technical success rates were compared between patients with and without traceable feeding arteries.ResultsA fully traceable feeding artery supplying 75% (44/59) of endoleaks in the cohort was identified. TAE was technically successful in 95% (42/44) of these cases but only in 13% (2/15) of the cases without a fully traceable feeding artery (P < .001). When the inferior mesenteric artery was the feeding artery, it was always fully traceable, and TAE was technically successful in 100% (33/33) of the cases. When a lumbar artery was the feeding artery, it was fully traceable in only 42% (11/26) of the cases. When the lumbar artery was not fully traceable, TAE was technically successful in only 13% (2/15) of the cases.ConclusionsThe traceability of a feeding artery over its entire course to an endoleak cavity using CT angiography was associated with TAE’s technical success. Lumbar feeding arteries were less likely to be fully traceable. TAE’s high failure rate when the feeding artery was not fully traceable suggests that translumbar embolization can be considered as an initial approach for theses patients.     

Angiographic Revascularization after Bariatric Embolization in a Swine Model

This study evaluated fundal arteriole angiographic revascularization after embolization with embolic microspheres of 3 different diameters in a swine model (16 swine, 31 arterioles). In the 50-μm group, 7 of 11 (64%) arterioles recanalized completely, 3 of 11 (27%) arterioles recanalized partially, and 1 of 11 (9%) arterioles had collateralization (no recanalization). In the 100- to 300-μm group, 7 of 10 (70%) arterioles recanalized completely and 3 of 10 (30%) arterioles) recanalized partially. In the 300- to 500-μm group, 7 of 10 (70%) arterioles recanalized completely, 1 of 10 (10%) arterioles recanalized partially, and 2 of 10 (20%) arterioles had collateralization. No difference was found between the groups in the degree of recanalization (P = .64). All embolized arterioles exhibited some degree of angiographic revascularization, irrespective of the microsphere size.     

Discrimination of High-Risk Type-2 Endoleak after Endovascular Aneurysm Repair through CT Perfusion: A Feasibility Study

A type-2 endoleak after an endovascular aneurysm repair is the most prevalent type of endoleak, but as the clinical consequence of its diagnosis is uncertain, at present, management decisions are solely based on aneurysm sac growth. The aim of this study was to investigate the potential of various computed tomography perfusion parameters for their ability to distinguish high-risk type-2 endoleaks from low-risk type-2 endoleaks after an endovascular aneurysm repair.     

Impact of Portal Hypertension on Adverse Events after Splenic Arterial Aneurysm Embolization

PurposeTo evaluate the outcomes of splenic artery aneurysm (SAA) embolization and compare adverse event (AE) rates after embolization in patients with and without portal hypertension (PHTN).Materials and MethodsA retrospective review of all patients who underwent embolization of SAAs at 2 institutions was performed (34 patients from institution 1 and 7 patients from institution 2). Baseline demographic characteristics, preprocedural imaging, procedural techniques, and postprocedural outcomes were evaluated. Thirty-day postprocedural severe and life-threatening AEs were evaluated using the Society of Interventional Radiology guidelines. Thirty-day mortality and readmission rates were also evaluated. t test, χ² test, and/or Fisher exact test were used for the statistical analysis.ResultsThere was no statistically significant difference between patients with and without PHTN in the location, number, and size of SAA(s). All procedures were technically successful. There were 13 (32%) patients with and 28 (68%) patients without PHTN. The 30-day mortality rate (31% vs 0%; P = .007), readmission rates (61% vs 7%; P < .001), and severe/life-threatening AE rates (69% vs 0%; P < .001) were significantly higher in patients with PHTN than in those without PHTN.ConclusionsThere was a significantly higher mortality and severe/life-threatening AE rate in patients with PHTN than in those without PHTN. SAAs in patients with PHTN need to be managed very cautiously, given the risk of severe/life-threatening AEs after embolization.     

Superior Rectal Artery Embolization with Tris-Acryl Gelatin Microspheres: A Randomized Comparison of Particle Size

PurposeTo evaluate the safety and efficacy of superior rectal artery embolization (SRAE) with different-sized tris-acryl gelatin microspheres in symptomatic hemorrhoidal disease (HD).Materials and MethodsForty-two patients (male, 30; female, 12; median age, 45 years) with symptomatic HD (2 grade I, 8 grade II, 17 grade III, and 15 grade IV) were divided into 3 experimental arms (500–700 μm, 700–900 μm, and 900–1,200 μm groups; each had 14 patients) in a prospective randomized style to perform SRAE. Follow-up was performed by rectoscopy, clinical examination, and questionnaires. The primary outcome measure was the clinical success rate at 12 months. Secondary outcome measures were technical success rate, recurrence rate, procedure-related mortality, procedure-related complications, and any outcome changes between particle sizes.ResultsNo procedure-related deaths or major morbidities were observed. There was a 54% minor complication rate (n = 23/42) in the treated zone: 45% sustained small superficial ulcerations (n = 19/42), 7% small rectosigmoid junction ulcerations (n = 3/42), and 2% small fibrotic scar tissue (n = 1/42). The clinical success rate was 93%. Of the groups, the best French bleeding score decrease was obtained in the 900–1,200 μm group. There were improvements in the quality of life score and visual analogue scale score after the SRAE procedure, although not in the Goligher score. No recurrent disease was observed.ConclusionsSRAE with tris-acryl gelatin microspheres for symptomatic HD is a safe and efficient treatment, with results favoring the use of larger microspheres.     

Transcatheter Arterial Sclerosing Embolization for the Treatment of Giant Propranolol-Resistant Infantile Hemangiomas in the Parotid Region

PurposeTo report the effectiveness and safety of transcatheter arterial sclerosing embolization (TASE) for the treatment of parotid infantile hemangiomas that did not respond appreciably to propranolol.Materials and MethodsA total of 21 infants (12 male and 9 female) with large propranolol-resistant infantile hemangiomas in the parotid region were enrolled in this study. During TASE, the feeding arteries of the lesions were embolized using pingyangmycin-lipiodol emulsion and polyvinyl alcohol particles (300–500 μm) to reduce the blood flow rate. All children were followed up as outpatients at 2 weeks and monthly thereafter. The curative effect was evaluated at the 1- and 3-month follow-up visits.ResultsNine lesions were located on the right side of the parotid gland, whereas 12 were located on the left side. The feeding arteries in all patients originated from branches of the external carotid artery. TASE was technically successful in all patients. The mean (± SD) maximal diameter of the hemangiomas significantly decreased from 6.50 cm ± 2.28 before treatment to 3.56 cm ± 1.84 at 1 month after TASE (P <. 05). Three months after TASE, the mean maximal diameter further significantly decreased to 1.94 cm ± 1.58 (P <. 05). During the follow-up period, 16 cases were rated as excellent and 5 as good; no recurrence or serious complications were noted. Minor side effects, such as slight pain, mild fever, and tissue swelling, were observed.ConclusionsTASE significantly decreased the size of the parotid hemangiomas with minor side effects during a short follow-up period.     

Bronchial Artery Aneurysm: Prevalence,Clinical Characteristics,and Long-Term Prognosis Following Bronchial Artery Embolization

PurposeTo investigate the prevalence, clinical characteristics, and long-term prognosis of bronchial artery aneurysm (BAA) following bronchial artery embolization (BAE).Materials and MethodsThe medical records of consecutive patients who underwent bronchial artery angiography between August 2013 and December 2019 were retrospectively reviewed. Patients who were diagnosed with BAA during this period were included in this study. The prevalence, patients’ characteristics, symptoms, comorbidities, angiographic findings, and long-term prognosis following BAE were investigated.ResultsBAA was observed in 20 of 508 patients who underwent bronchial artery angiography (3.9%). The patients’ median age was 69 (interquartile range [IQR], 63.5–76.7) years. The main causes of BAA were cryptogenic, bronchiectasis or cystic fibrosis, and pulmonary aspergillosis. The median diameter of ruptured BAAs was significantly smaller than that of unruptured BAAs (5.4 mm [IQR, 4.8–7.3 mm] vs 9.0 mm [IQR, 7.2–13.9 mm], P = .009). All the patients were successfully treated with BAE, without major adverse events. The median follow-up period after BAE was 970 (IQR, 561–1,796) days. The BAA-related survival rate was 100% at 2 and 3 years after BAE, and the overall survival rate after BAE was 89.2% (95% confidence interval [CI] 89.0–89.3) at 2 years and 74.3% (95% CI 74.0–74.5) at 3 years. BAA-related adverse events and mortality did not occur during the follow-up period.ConclusionsBAA was observed in 3.9 % (20/508) of the patients who underwent bronchial artery angiography. All the patients with BAA were successfully treated with BAE. BAA rupture and consequent mortality did not occur during the follow-up period.     

Comparison of Transthoracic Contrast Echocardiography with High-Resolution Chest CT after Embolization of Pulmonary Arteriovenous Malformation

PurposeTo compare postembolotherapy follow-up graded transthoracic contrast echocardiography (TTCE) and high-resolution computed tomography (CT) of the chest and to evaluate the use of graded TTCE in the early postembolic period.Materials and MethodsThirty-five patients (6 men and 29 women; mean age, 56 years; range, 27–78 years) presenting for postembolotherapy follow-up between 2017 and 2021 with concurrent high-resolution CT and graded TTCE were analyzed retrospectively. Untreated pulmonary arteriovenous malformations (PAVMs) with a feeding artery of ≥2 mm were considered treatable.ResultsNinety-four percent of patients (33 of 35) did not have treatable PAVMs on high-resolution CT. TTCE was negative for shunts (Grade 0) in 34% of patients (n = 12). Of patients with a TTCE positive for shunts (23 of 35, 66%), 83% had a Grade 1 shunt, 13% had a Grade 2 shunt, and 4% had a Grade 3 shunt. No patient with a Grade 0 or 1 shunt had a treatable PAVM on high-resolution CT. Of the 2 patients with PAVMs requiring treatment, one had a Grade 2 shunt and one had a Grade 3 shunt. TTCE grade was significantly associated with the presence of a treatable PAVM on high-resolution CT (P < .01).ConclusionsGraded TTCE predicts the need for repeat embolotherapy and does so reliably in the early postembolotherapy period. This suggests that graded TTCE can be utilized in the postembolotherapy period for surveillance, which has the potential to lead to a decrease in cumulative radiation in this patient population.     

Outcomes of Preventive Embolization of the Inferior Mesenteric Artery during Endovascular Abdominal Aortic Aneurysm Repair

PurposeTo evaluate the impact of preemptive inferior mesenteric artery (IMA) embolization on outcomes of endovascular abdominal aortic aneurysm (AAA) repair (EVAR).Materials and MethodsFrom January 2015 to July 2017, all patients undergoing elective EVAR or fenestrated EVAR (F-EVAR) for asymptomatic AAA in a single tertiary hospital were retrospectively included. Three groups of patients were defined: patients with a patent IMA who underwent embolization during EVAR/F-EVAR (group 1), those with a patent IMA who did not undergo embolization during EVAR/F-EVAR (group 2), and those with a chronically occluded IMA (group 3). Preoperative aortic morphology, demographics, and procedural details were recorded. Aneurysmal growth (≥5 mm), reintervention, and overall mortality rates were analyzed using multivariate proportional hazard multivariate modeling. Propensity scores were constructed, and inverse probability weighting was applied to a new set of multivariate analyses to perform a sensitivity analysis.ResultsA total of 266 patients (male, 95% [n = 249]) with a median age of 70 (65–77) years were included, with F-EVAR procedures comprising 87 (32.7%) of the interventions. There were 52, 142, and 72 patients in groups 1, 2, and 3, respectively. Changes in aneurysmal sac size did not differ between groups, nor did overall survival or reintervention rates at 24 months. IMA embolization was not identified as an independently protective factor for aneurysmal growth during follow-up (relative risk [RR] = 2.82/mm [0.96–8.28], P = .060), whereas accessory renal arteries (RR = 5.07/mm [1.72–14.96], P = .003) and a larger preoperative aneurysmal diameter (RR = 1.09/mm [1.03–1.15], P = .004) were independent risk factors for sac enlargement.ConclusionsPreventive embolization of the IMA during EVAR or F-EVAR did not promote aneurysmal sac shrinking or decrease the reintervention rate at 2-year follow-up.     

Effects of Antithrombotic Therapy on Abdominal Aortic Aneurysm Sac Size after Endovascular Repair in Patients with Favorable Neck Anatomy

PurposeTo evaluate the influence of antiplatelet or anticoagulant therapy on sac behavior after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA).Materials and MethodsThis study retrospectively analyzed data from patients with favorable neck anatomy who underwent EVAR between 2007 and 2019. Patients with ruptured AAA and ≤1 year of sac behavior evaluation were excluded. Sac shrinkage after 1 year, persistent type II endoleak, and late sac expansion were examined.ResultsIn total, 182 patients with favorable neck anatomy were included in this study. A multivariable analysis identified an occluded inferior mesenteric artery (IMA; P = .049), the presence of a posterior thrombus (P = .009), and no antiplatelet therapy (P = .012) as factors positively associated with sac shrinkage at 1 year. Persistent type II endoleak was detected in 56 (30.8%) patients, with patent IMA (P = .006), the lack of a posterior thrombus (P = .004), the number of patent lumbar arteries (P = .004), and antiplatelet therapy (P = .039) being identified as significant risk factors. The multivariable analysis identified a larger initial AAA diameter (P < .001), the lack of a posterior thrombus (P = .038), and antiplatelet and anticoagulant therapies (P = .038 and P = .003, respectively) as risk factors for late sac expansion.ConclusionsAfter EVAR in patients with favorable neck anatomy, antiplatelet therapy is associated with the lack of sac regression at 1 year, whereas antiplatelet and anticoagulant therapies are risk factors for late sac expansion.     

Venous Sac and Feeding Artery Embolization versus Feeding Artery Embolization Alone for Treating Pulmonary Arteriovenous Malformations: Draining Vein Size Outcomes

PurposeTo investigate and compare venous sac and feeding artery embolization (VFE) with feeding artery embolization (FAE) alone for treatment of pulmonary arteriovenous malformations (PAVMs), based on difference in outcomes in decrease of the size of the draining vein.Materials and MethodsTwenty-six patients (7 male and 19 female; median age [interquartile range], 58 years [46–65 years]) with 42 simple PAVMs treated with coil embolization between August 2005 and December 2018 were retrospectively evaluated. Twenty PAVMs were treated with FAE early in the study period and compared with 22 PAVMs treated with VFE later in the study period. Follow-up computed tomography images obtained 8–20 months after embolotherapy were used for outcome analysis. Data related to patient demographics; follow-up period; baseline diameters of the feeding artery, venous sac, and draining vein; draining vein diameter after treatment; and decrease in the size of the draining vein, including the number reaching a threshold of 70% decrease, were compared between the 2 groups.ResultsThe draining vein decreased in size by a median of 46.4% in the FAE group and 66.3% in the VFE group, and the difference between the 2 groups was statistically significant (P = .009). There were no significant differences in the other parameters.ConclusionsVFE leads to a greater decrease in the size of the draining vein than FAE, suggesting that VFE results in more complete occlusion than FAE for treatment of PAVMs.     

Assessing the Effects of Geniculate Artery Embolization in a Nonsurgical Animal Model of Osteoarthritis

PurposeTo create a nonsurgical animal model of osteoarthritis (OA) to evaluate the effects of embolotherapy during geniculate artery embolization (GAE).Materials and MethodsFluoroscopy-guided injections of 700 mg of sodium monoiodoacetate were performed into the left stifle in 6 rams. Kinematic data were collected before and after induction. At 10 weeks after induction, Subjects 1 and 4–6 underwent magnetic resonance (MR) imaging with dynamic contrast enhancement (DCE) and Subjects 1, 3, and 4–6 underwent angiography with angiographic scoring to identify regions with greatest disease severity for superselective embolization (75–250-μm microspheres). Target vessel size was measured. At 24 weeks after angiography, DCE-MR imaging, angiography, and euthanasia were performed, and bilateral stifles were harvested. Medial/lateral tibial and femoral condylar, patellar, and synovial samples were cut, preserved, decalcified, and scored using the Osteoarthritis Research Society International criteria. The stifle and synovium Whole-Organ Magnetic Resonance Imaging Score and Multicenter Osteoarthritis Study score were determined. The volume transfer constant (K_trans) and extracellular volume fraction (v_e) were calculated from DCE-MR imaging along the lateral synovial regions of interest.ResultsThe mean gross and microscopic pathological scores were elevated at 38 and 61, respectively. Mean synovitis score was elevated at 9.2. Mean pre-embolization and postembolization angiographic scores were 5 and 3.8, respectively. Mean superior, transverse, and inferior geniculate artery diameters were 3.1 mm ± 1.21, 2.0 mm ± 0.50, and 1.6 mm ± 0.41 mm, respectively. Mean pre-embolization and postembolization cartilage and synovitis scores were elevated at 35.13 and 73.3 and 5.5 and 9.2, respectively. The K_trans/v_e values of Subjects 4, 5, and 6 were elevated at 0.049/0.38, 0.074/0.53, and 0.065/0.51, respectively. Altered gait of the hind limb was observed in all subjects after induction, with reduced joint mobility. No skin necrosis or osteonecrosis was observed.ConclusionsA nonsurgical ovine animal knee OA model was created, which allowed the collection of angiographic, histopathological, MR imaging, and kinematic data to study the effects of GAE.     

The Safety and Effectiveness of Hepatic Transarterial Embolic Locoregional Therapy in Patients with Contraindications to Hepatectomy after Portal Vein Embolization

The safety and effectiveness of hepatic transarterial embolic locoregional therapy (LRT) was assessed, including transarterial chemoembolization (TACE) and transarterial radioembolization (TARE), in patients who underwent portal vein embolization (PVE) before major hepatectomy in whom surgery was then contraindicated. Adverse events (AEs) were graded according to the Society of Interventional Radiology classification of AEs. Tumor response was assessed based on the Response Evaluation Criteria In Solid Tumors 1.1. Overall survival (OS) and progression-free survival (PFS) were estimated. Fifteen patients underwent 37 transarterial LRTs (25 TACEs, 11 TAREs, and 1 bland embolization), most (73%) with hepatocellular carcinoma. Eleven AEs occurred in 7 patients, including 2 Grade 3/5 (severe) and 2 Grade 4/5 (life-threatening) events. The best response was partial response in 4 (27%) and stable disease in 10 (66%) patients. The median OS and PFS were 42 (95% CI, 35–49 months) and 33 months (95% CI, 24–42 months), respectively. In conclusion, hepatic transarterial LRT can be considered as a therapeutic option in patients with contraindicated liver surgery after PVE.     

Transarterial Embolization of Liver Cancer in a Transgenic Pig Model

PurposeTo develop and characterize a porcine model of liver cancer that could be used to test new locoregional therapies.Materials and MethodsLiver tumors were induced in 18 Oncopigs (transgenic pigs with Cre-inducible TP53^R167H and KRAS^G12D mutations) by using an adenoviral vector encoding the Cre-recombinase gene. The resulting 60 tumors were characterized on multiphase contrast-enhanced CT, angiography, perfusion, micro-CT, and necropsy. Transarterial embolization was performed using 40–120 μm (4 pigs) or 100–300 μm (4 pigs) Embosphere microspheres. Response to embolization was evaluated on imaging. Complications were determined based on daily clinical evaluation, laboratory results, imaging, and necropsy.ResultsLiver tumors developed at 60/70 (86%) inoculated sites. Mean tumor size was 2.1 cm (range, 0.3–4 cm) at 1 week. Microscopically, all animals developed poorly differentiated to undifferentiated carcinomas accompanied by a major inflammatory component, which resembled undifferentiated carcinomas of the human pancreatobiliary tract. Cytokeratin and vimentin expression confirmed epithelioid and mesenchymal differentiation, respectively. Lymph node, lung, and peritoneal metastases were seen in some cases. On multiphase CT, all tumors had a hypovascular center, and 17/60 (28%) had a hypervascular rim. After transarterial embolization, noncontrast CT showed retained contrast medium in the tumors. Follow-up contrast-enhanced scan showed reduced size of tumors after embolization using either 40–120 μm or 100–300 μm Embosphere microspheres, while untreated tumors showed continued growth.ConclusionsLiver tumors can be induced in a transgenic pig and can be successfully treated using bland embolization.     

Intra-Arterial Lidocaine Administration for Anesthesia after Uterine Artery Embolization with Trisacryl Gelatin Microspheres for Leiomyoma

PurposeTo evaluate whether administration of lidocaine into the uterine artery for anesthesia immediately after uterine artery embolization (UAE) with trisacryl gelatin microspheres (TAGM) for leiomyoma is safe and effective.Materials and MethodsIn a single-institution retrospective study, 100 patients underwent UAE using TAGM with a pruned tree endpoint between June 2014 and April 2019. The first 50 patients (control group) underwent UAE without lidocaine; in the second 50 patients (study group), lidocaine was administered into the uterine artery immediately after UAE. Baseline characteristics and technical and periprocedural outcomes were compared. Visual analog scale (VAS) scores 0, 3, 6, 9, 12, and 18 hours after UAE were compared between the groups with repeated measures analysis of variance. Each multivariate-adjusted VAS score < 24 hours was compared with analysis of covariance.ResultsNo significant differences were observed in baseline characteristics or technical and periprocedural outcomes, including the volume of morphine used (P = .415), between the groups. No significant differences were found in crude or multivariate-adjusted VAS scores at each time point < 24 hours. Only the multivariate-adjusted VAS score 3 hours after UAE was 0.7 lower in the study group (mean ± SE, 2.2 ± 0.3 vs 2.9 ± 0.3); however, no significant difference was noted (P = .070). No adverse events associated with lidocaine were detected.ConclusionsIntra-arterial lidocaine administration immediately after UAE with TAGM for leiomyoma was safe, but did not contribute to significant reductions in pain or volume of narcotic agent administered.     

Multicenter Randomized Sham Controlled Study of Genicular Artery Embolization for Knee Pain Secondary to Osteoarthritis

PurposeTo assess the safety and efficacy of genicular artery embolization (GAE) compared with a sham procedure in the treatment of knee pain secondary to mild to moderate osteoarthritis (OA).Materials and MethodsA multicenter, single-blinded, randomized controlled trial was conducted to evaluate knee OA symptom reduction after GAE versus sham procedure. Subjects (n = 21) with mild to moderate OA and intractable knee pain were randomized 2:1 to either GAE or a sham procedure. Subjects who were randomized to the sham procedure and did not report clinical improvement in both the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analog scale (VAS) scores were unblinded and able to crossover to treatment at 1 month. Longitudinal data were collected for 12 months, and subjects were excluded if they required additional analgesics at follow-up. Reductions in the VAS and total WOMAC scores were compared using mixed-effects linear regression models.ResultsAll subjects in the sham group failed to show significant improvements at 1 month and crossed over to the treatment arm. There was a statistically significantly greater pain reduction in the treatment group than in the sham group at 1 month (VAS, 50.1 mm; standard error [SE], 10.6; 95% confidence interval [CI], 29.0, 72.3; P<.01). Disability improvement was also significantly greater in the treatment group (WOMAC, 24.7 points; SE, 10.4; 95% CI, 3.5, 45.9; P=.02). Only minor adverse events were reported. Five subjects were excluded after increased analgesic use. Sensitivity analysis with all excluded patients confirmed significant improvements at 1 and 12 months.ConclusionIn patients with mild to moderate knee OA, GAE results in symptomatic improvement greater than the sham procedure with clinically significant reduction in pain and disability.     

Randomized Controlled Study of an Absorbable Vena Cava Filter in a Porcine Model

PurposeTo compare the safety and efficacy of an absorbable inferior vena cava (IVC) filter and a benchmark IVC filter in a porcine model.Materials and MethodsA randomized controlled Good Laboratory Practice study was performed in Domestic Yorkshire cross swine. Sixteen swine were implanted with an absorbable IVC filter (test device; Adient Medical, Pearland, Texas); 8 were implanted with a benchmark metal IVC filter (control device; Cook Medical, Bloomington, Indiana). All animals underwent rotational digital subtraction pulmonary angiography and cavography (anteroposterior and lateral) before filter deployment and 5 and 32 weeks after deployment. Terminal procedures and necropsy were performed at 32 weeks. The IVC, heart, lungs, liver, and kidneys were harvested at necropsy. The reported randomized controlled GLP animal study was conducted at Synchrony Labs, Durham, North Carolina.ResultsOne animal died early in the test cohort of a recurring hemorrhage at the femoral access site resulting from a filter placement complication. All other animals remained clinically healthy throughout the study. No pulmonary embolism was detected at the 5- and 32-week follow-up visits. The absorbable filter subjects experienced less caval wall perforation (0% vs 100%) and thrombosis (0% vs 75%). The control device routinely perforated the IVC and occasionally produced collateral trauma to adjacent tissues (psoas muscle and aorta). The veins implanted with the absorbable filter were macroscopically indistinguishable from normal adjacent veins at 32 weeks except for the presence of radiopaque markers. Nontarget tissues showed no device-related changes.ConclusionsImplantation of the absorbable IVC filter in swine proved safe with no pulmonary emboli detected. There was complete to near-complete resorption of the filter polymer by 32 weeks with restoration of the normal appearance and structure of the IVC.     

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.     

Prostatic Artery Embolization for Benign Prostatic Hyperplasia: Bleomycin-Eluting versus Bland Microspheres in a Canine Model

PurposeTo prospectively assess safety and efficacy of prostatic artery embolization (PAE) with bleomycin-eluting microspheres for benign prostatic hyperplasia (BPH) in a canine model.Materials and MethodsTwelve adult male beagles (mean age, 1.6 y ± 0.2; range, 1.2–2.0 y) were randomly assigned to group A (n = 6; PAE with bleomycin-eluting 30–60-μm HepaSphere microspheres) and group B (n = 6; PAE with bland 30–60-μm HepaSphere microspheres) between April 2017 and November 2018. Plasma bleomycin concentration in group A was measured within 7 days. Prostate volume (PV) and ischemic volume after PAE were measured by magnetic resonance imaging. Prostates and adjacent organs were harvested after the last magnetic resonance study and histopathologically examined.ResultsPlasma bleomycin concentration peaked at 10 minutes at 2,055.0 ng/mL ± 606.1 and lasted for 1,440 min at low levels after PAE. PV reduction percentage was greater in group A than in group B at 1 month (74.1% ± 4.3 vs 63.7% ± 3.5; P = .006) and 3 months (61.5% ± 6.7 vs 46.1% ± 3.8; P = .001) after PAE. Proportion of prostate ischemic volume was greater in group A than in group B (75.3% ± 3.0 vs 62.0% ± 7.1; P = .006) at 1 month after PAE. Proportion of prostate ischemic volume at 1 month positively correlated with PV percentage reduction at 3 months in group A (r = 0.840, P = .036) and group B (r = 0.844, P = .035). There were no complications or nontarget embolization to surrounding organs after the procedures.ConclusionsIn a canine model, PAE with bleomycin-eluting microspheres was feasible and well tolerated and caused ischemic necrosis and reduction in PV.