A systematic review of diagnostic and interventional techniques in non-occlusive hepatic artery hypoperfusion syndrome.

OBJECTIVE: This systematic review aims to elucidate the diagnostic capabilities of imaging techniques in identifying Non-Occlusive Hepatic Artery Hypoperfusion Syndrome (NOHAH) and to evaluate the efficacy and outcomes of splenic artery embolization (SAE), including the choice and placement of embolic agents. MATERIALS AND METHODS: A comprehensive literature search was conducted using PubMed, CINAHL, and Scopus databases, adhering to PRISMA guidelines. Fifteen studies encompassing 240 patients treated with embolization (using coils or Amplatzer Vascular Plugs (AVP)) were analyzed. Key metrics assessed included patient demographics, embolization techniques, embolic agents, technical success, radiologic findings pre- and post-embolization, and complication rates. RESULTS: Among the 240 patients studied, 177 (73.8%) were reported by gender, with a majority being male (127/177, 71.7%). Doppler ultrasonography (DUS) emerged as the primary initial screening tool in 80% of studies. The hepatic arterial resistive index (RI) was a critical parameter, with mean values significantly decreasing from 0.84 pre-embolization to 0.70 post-embolization (p < 0.001). All cases confirmed technical success via digital subtraction angiography, revealing delayed hepatic arterial filling without stenosis or thrombosis. Coils were the predominant embolic agent, used in 80.8% of patients, followed by AVP in 16.3%. The overall mortality rate was 4.58%, with 29 major and 3 minor complications noted. Notably, proximal placement of coils in the splenic artery was associated with lower mortality rates compared to distal placement and showed comparable complication rates to AVPs. CONCLUSION: DUS is a reliable screening modality for NOHAH, with post-SAE assessments showing significant improvements. The choice and location of embolization significantly impact patient outcomes, with proximal placement of coils emerging as a preferable strategy due to lower mortality rates and comparable complication profiles to alternative methods.

Digital light 4D printing of bioresorbable shape memory elastomers for personalized biomedical implantation.

Four-dimensional (4D) printing unlocks new potentials for personalized biomedical implantation, but still with hurdles of lacking suitable materials. Herein, we demonstrate a bioresorbable shape memory elastomer (SME) with high elasticity at both below and above its phase transition temperature (Ttrans). This SME can be digital light 3D printed by co-polymerizing glycerol dodecanoate acrylate prepolymer (pre-PGDA) with acrylic acid monomer to form crosslinked Poly(glycerol dodecanoate acrylate) (PGDA)-Polyacrylic acid (PAA), or PGDA-PAA network. The printed complex, free-standing 3D structures with high-resolution features exhibit shape programming properties at a physiological temperature. By tuning the pre-PGDA weight ratios between 55 wt% and 70 wt%, Ttrans varies between 39.2 and 47.2 ℃ while Young's moduli (E) range 40-170 MPa below Ttrans with fractural strain (εf) of 170 %-200 %. Above Ttrans, E drops to 1-1.82 MPa which is close to those of soft tissue. Strikingly, εf of 130-180 % is still maintained. In vitro biocompatibility test on the material shows > 90 % cell proliferation and great cell attachment. In vivo vascular grafting trials underline the geometrical and mechanical adaptability of these 4D printed constructs in regenerating the aorta tissue. Biodegradation of the implants shows the possibility of their full replacement by natural tissue over time. To highlight its potential for personalized medicine, a patient-specific left atrial appendage (LAA) occluder was printed and implanted endovascularly into an in vitro heart model. STATEMENT OF SIGNIFICANCE: 4D printed shape-memory elastomer (SME) implants particularly designed and manufactured for a patient are greatly sought-after in minimally invasive surgery (MIS). Traditional shape-memory polymers used in these implants often suffer from issues like unsuitable transition temperatures, poor biocompatibility, limited 3D design complexity, and low toughness, making them unsuitable for MIS. Our new SME, with an adjustable transition temperature and enhanced toughness, is both biocompatible and naturally degradable, particularly in cardiovascular contexts. This allows implants, like biomedical scaffolds, to be programmed at room temperature and then adapt to the body's physiological conditions post-implantation. Our studies, including in vivo vascular grafts and in vitro device implantation, highlight the SME's effectiveness in aortic tissue regeneration and its promising applications in MIS.

Knee and Shoulder Vascular Anatomy.

In the past decade, angiographic studies have demonstrated neovessels in or in the vicinity of affected joints in many musculoskeletal conditions that used to be considered wear and tear joint disease, such as knee osteoarthritis, frozen shoulder, and overuse injuries. The novelty of this finding is showing the presence of neovascularity at an angiographically detectable level, as compared to histologically evident neovessels that had been discovered years ago. These neovessels have now become the target of interventions in a growing field called muscoskeletal embolotherapy. An in-depth and all-encompassing understanding of the vascular anatomy that could specifically assist performing of these procedures is paramount. Such an understanding will help ensure success in clinical outcomes and avoid much dreaded complications. This review discusses the vascular anatomy relevant to the 2 most commonly performed musculoskeletal embolotherapies, genicular artery embolization and transarterial embolization for frozen shoulder.

Post-Embolization Hemoglobin Changes: When to Consider Re-intervention.

PURPOSE: Decline in hemoglobin (Hgb) levels is common post-embolization, but there is no consensus on the classification of patients based on risk for re-bleeding or re-intervention. The current study evaluated post-embolization Hgb level trends with the goal of understanding the factors predictive of re-bleeding and re-intervention. MATERIALS AND METHODS: All patients who underwent embolization for gastrointestinal (GI), genitourinary, peripheral, or thoracic arterial hemorrhage from 01/2017 to 01/2022 were reviewed. Data included demographics, periprocedural pRBC transfusion (TF) or pressor requirements, and outcome. Lab data consisted of Hgb values pre-embolization, immediately post-embolization, and daily values on days 1-10 after embolization. Hgb trends were compared between patients across TF and re-bleeding outcomes. Regression model was used to examine factors predictive of re-bleeding and magnitude of Hgb reduction post-embolization. RESULTS: A total of 199 patients were embolized for active arterial hemorrhage. Perioperative Hgb level trends were similar for all sites and between TF + and TF- patients, showing a decline reaching a nadir within 6 days post-embolization followed by an upward trend. Maximum Hgb drift was predicted by GI embolization (p = 0.018), TF before embolization (p = 0.001), and use of vasopressor (p = 0.000). Patients with Hgb drop > 15% within the first two days post-embolization had a higher chance of having a re-bleeding episode (p = 0.04). CONCLUSION: Perioperative Hgb trends showed a consistent downward drift followed by an upward shift, irrespective of TF requirement status or site of embolization. Using a cut-off value of 15% Hgb reduction within the first two days post-embolization may be helpful to assess re-bleeding risk.

Thermal Ablation in the Liver: Heat versus Cold-What Is the Role of Cryoablation?

Cryoablation is commonly used in the kidney, lung, breast, and soft tissue, but is an uncommon choice in the liver where radiofrequency ablation (RFA) and microwave ablation (MWA) predominate. This is in part for historical reasons due to serious complications that occurred with open hepatic cryoablation using early technology. More current technology combined with image-guided percutaneous approaches has ameliorated these issues and allowed cryoablation to become a safe and effective thermal ablation modality for treating liver tumors. Cryoablation has several advantages over RFA and MWA including the ability to visualize the ice ball, minimal procedural pain, and strong immunomodulatory effects. This article will review the current literature on cryoablation of primary and secondary liver tumors, with a focus on efficacy, safety, and immunogenic potential. Clinical scenarios when it may be more beneficial to use cryoablation over heat-based ablation in the liver, as well as directions for future research, will also be discussed.

Varicocele Embolization: Interventional Radiologist's Perspective.

The goal of this article is to review the patient selection criteria, technical pearls, and outcomes of percutaneous varicocele embolization. This article will provide a brief overview of the history of the procedure, angiographic approach, and materials used in contemporary embolization. The success rates and complications of the varicocele embolization will also be discussed.

Emerging Targets for the Treatment of Osteoarthritis: New Investigational Methods to Identify Neo-Vessels as Possible Targets for Embolization.

Osteoarthritis (OA) is the major cause of disability, affecting over 30 million US adults. Continued research into the role of neovascularization and inflammation related to osteoarthritis in large-animal models and human clinical trials is paramount. Recent literature on the pathogenetic model of OA has refocused on low-level inflammation, resulting in joint remodeling. As a result, this has redirected osteoarthritis research toward limiting or treating joint changes associated with persistent synovitis. The overall goal of this review is to better understand the cellular and tissue-specific mechanisms of inflammation in relation to a novel OA treatment modality, Genicular Artery Embolization (GAE). This article also assesses the utility and mechanism of periarticular neovascular embolization for the treatment of OA with a particular emphasis on the balance between pro-angiogenic and anti-angiogenic cytokines, inflammatory biomarkers, and imaging changes.

Particle Distribution in Embolotherapy, How Do They Get There? A Critical Review of the Factors Affecting Arterial Distribution of Embolic Particles.

Embolization has tremendously evolved in recent years and has expanded to treatment of a variety of pathologic processes. There has been emerging evidence that the level of arterial occlusion and the distribution of embolic particles may play an important role in the clinical outcome. This is a comprehensive literature review to identify variables that play important role in determination of level of occlusion of blood vessels and distribution of embolic particles. The literature searches between 1996 to 2020 through PubMed and Ovid-MEDLINE yielded over 1030 articles of which 30 studies providing details on the level of occlusion are reviewed here. We divided the playing factors into characteristics of the particles, solution/injection and vascular bed. Accordingly, particle size, type and aggregation, compressibility/deformability, and biodegradability are categorized as the factors involving particles' behavioral nature. Infusion rate and concentration/dilution of the medium are related to the carrying solution. Hemodynamics and the arterial resistance are characteristics of the vascular bed that also play an important role in the distribution of embolic particles. Understanding and predicting the level of embolization is a complex multi-factor problem that requires more evidence, warranting further randomized controlled trials, and powered human and animal studies.

Hemorrhoid embolization: A review of current evidences.

Hemorrhoids are local vascular structure dilations in the lower rectum, associated with morbidity and reduced quality of life. Endovascular coil or particle embolization of the superior rectal arteries, known as Emborrhoid technique, is a minimally invasive, image-guided therapy that targets the hemorrhoidal plexus and reduces hemorrhage. The purpose of this review was to analyze the results of published studies to determine the efficacy, clinical outcomes, and morbidities associated with the endovascular occlusion of hemorrhoidal arteries for the treatment of internal hemorrhoids. Current evidences suggest that hemorrhoids treated by Emborrhoid technique using microcoils, embolic particles or a combination is safe with no reported serious complications. Hemorrhoid embolization can preserve the anal tone without direct anorectal trauma and maintain the hemorrhoidal tissue in place requiring minimal local wound care on an outpatient basis. However, due to the paucity of high-quality trials, further research is warranted to evaluate its long-term outcomes, compare its efficacy with other treatment modalities, and fully assess its role in the treatment of hemorrhoid.

Osteoarthritis-Related Knee Pain Treated With Genicular Artery Embolization: A Systematic Review and Meta-analysis.

BACKGROUND: Genicular artery embolization (GAE) is an innovative technique that has been investigated as a supplementary treatment method for chronic pain secondary to knee osteoarthritis (OA). PURPOSE: To evaluate the current evidence on the effectiveness and safety of GAE for OA-related knee pain. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: A systematic literature search was conducted in the PubMed, Web of Science, EMBASE, and Scopus databases to identify studies related to knee OA treated with GAE. Treatment agents were categorized as Embozene, imipenem/cilastatin, resorbable microspheres, and polyvinyl alcohol. The main outcomes were the mean difference (MD) in pre- and postembolization pain based on the visual analog scale (VAS) or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores as well as changes in the need for pain medication. Random- and fixed-effects models were applied for data analysis. RESULTS: Of 379 initially inspected publications, 11 (N = 225 patients; 268 knees) were included in the final review. The quality of the studies was fair in 8 and poor in 3-categorized according to the National Institutes of Health quality assessment tool. Overall, 119, 72, 13, and 21 patients were treated with imipenem/cilastatin, Embozene, resorbable microspheres, and polyvinyl alcohol, respectively. Symptomatic improvement was reported in all studies. The pooled effect size, characterized by MD, showed a significant improvement in the VAS and WOMAC pain scores, with better functional status after GAE. Pre- versus postembolization MDs in VAS scores ranged from 32 within the first week to 58 after a 2-year follow-up (equivalent to 54% and 80% improvement, respectively). There was a similar trend in the overall WOMAC scores, with MDs ranging from 28.4 to 36.8 (about 58% and 85% improvement, respectively). GAE resulted in a decreased need for pain medication for knee OA, with a 27%, 65%, and 73% decline in the number of patients who used opioids, nonsteroidal anti-inflammatory drugs, and intra-articular hyaluronic acid injection, respectively (P < .00001 for all). No significant difference between embolic agents was seen with regard to post-GAE pain reduction. No severe or life-threatening complications were reported. CONCLUSION: OA treated by GAE using different embolic particles can be considered generally safe, with good efficacy and no reported serious complications.

Splenic Artery Embolization for Treatment of Iatrogenic Kasabach-Merritt Phenomenon Following Failed Endovascular Splenic Artery Aneurysm Repair.

Stent grafts are utilized to treat and exclude visceral arterial aneurysms while preserving flow through the vessel. Stent-associated thrombocytopenia is a rare complication not typically seen with modern stents. The following case describes the clinical presentation of stent kinking and consumptive coagulopathy. Stent-associated microangiopathic hemolytic anemia was inferred from protracted workup and exclusion of alternative diagnoses. Despite the risk of arterial puncture in the setting of profound thrombocytopenia, the patient was successfully treated with stent embolization with near immediate rebound in platelet count. This case report documents the presentation of rare stent-associated thrombocytopenia leading to challenging diagnostic evaluation and necessitating high-risk intervention.

Recanalization and Reconstruction of a Chronically Occluded Inferior Vena Cava Through an Existing Transjugular Intrahepatic Portosystemic Shunt in the Setting of Budd-Chiari Syndrome.

Budd-Chiari syndrome (BCS) results from the occlusion or flow reduction in the hepatic veins or inferior vena cava and can be treated with transjugular intrahepatic portosystemic shunt when hepatic vein recanalization fails.1-3 Hypercoagulable patients with primary BCS are predisposed to development of new areas of thrombosis within the TIPS shunt or IVC. This case details a patient with BCS, pre-existing TIPS extending to the right atrium, and chronic retrohepatic IVC thrombosis who underwent sharp recanalization of the IVC with stenting into the TIPS stent bridging the patient until his subsequent hepatic transplantation.

Successful Percutaneous Transcatheter Closure of a Common Femoral Artery Pseudoaneurysm With Use of MicroVascular Plug Despite Continued Catheter-Directed Thrombolysis.

Common femoral artery pseudoaneurysm is a known complication of percutaneous vascular access. Treatment options include surgical repair of the pseudoaneurysm or endovascular methods such as ultrasound-guided compression and direct thrombin injection into the pseudoaneurysm sac. Treatment of pseudoaneurysm is more challenging when a patient is undergoing concurrent catheter-directed or systemic thrombolytic therapy. This is a case report of endovascular treatment of an iatrogenic pseudoaneurysm of common femoral artery in a patient receiving concurrent catheter-directed thrombolytic therapy. This was performed successfully by precise deployment of a MicroVascular Plug into the pseudoaneurysm neck with immediate closure of pseudoaneurysm. Midterm follow-up confirmed sustained exclusion of the pseudoaneurysm sac with continued patency of the treated femoral artery.

Comparison of tandem ureteral stents, cryoplasty, and cutting balloon ureteroplasty in treatment of refractory transplant ureteral strictures.

The objective of study was to compare clinical outcome of cryoplasty, tandem stents, and cutting balloon ureteroplasty as "bailout procedures" to prevent surgical intervention or stent dependency in renal transplant patients with refractory ureteral stricture. All patients who underwent a bailout procedure from June 11, 2003, to August 8, 2015, at a single institution were reviewed retrospectively. Refractory ureteral stricture was defined as ureteral stenosis not responding to at least two prior percutaneous plain balloon ureteroplasties. Primary patency was defined as stable allograft function following the procedure with unobstructed urine outflow, not requiring indwelling ureteral stent, repeat ureteroplasty, or surgical revision. Sixty-one procedures were performed on 51 patients. Patients were followed up for a median of 286 days. Overall primary patency rate was 26.1%. Primary patency rate by method was 38.1%, 23.1%, and 14.3% after cryoplasty, tandem stent placement, and cutting balloon dilatation, respectively (P = .260). Primary patency rate was higher in early (<3 months post-transplant) ureteral strictures (35.7% vs 13.3%; P = .047). More complications identified in patients who had tandem ureteral stents (P = .00754). As some renal transplant patients may not be good operative candidates for ureteral revision, it would be reasonable to attempt one of these "bailout" interventions as long as the clinical team and patient are aware of overall low potential for achieving primary patency.

Recurrent Ectopic Variceal Bleed After Pancreas Transplantation With No Portal Hypertension: Case Report and Outcomes of Endovascular Onyx Embolization.

A 57-year-old male presented with intermittent gastrointestinal bleeding (GIB) 1 year after a successful simultaneous pancreas and kidney transplant. No source could be found after 5 tagged red blood cell studies, 3 computed tomographies (CTs), 7 endoscopies, and 4 catheter angiograms. Review of CTs showed pathologically enlarged superior mesenteric vein branches near a jejunal segment near pancreas graft. Transhepatic superior mesenteric venogram showed varicosities near jejunum, which were obliterated with ethylene vinyl alcohol (Onyx). Follow-up CTs confirmed complete obliteration, but he had more GIBs and eventually underwent native jejunal and donor duodenal resection. He has remained GIB-free for 12 months.

CT Fluoroscopic-Guided Coil Localization of Lung Nodules prior to Video-Assisted Thoracoscopic Surgical Resection Reduces Complications Compared to Hook Wire Localization.

PURPOSE: To compare the safety and efficacy of hook wire versus microcoil localization of pulmonary nodules prior to video-assisted thoracoscopic resection (VATS). MATERIALS AND METHODS: A retrospective comparative review was conducted of 46 patients (26 hook wire and 20 microcoil) who underwent computed tomography fluoroscopic-guided nodule localizations prior to VATS in a single center between January 2012 and August 2016. Nodule characteristics, procedural details, clinical outcomes, and pathologic findings were collected. Baseline characteristics and lung nodule distribution were not significantly different between the 2 groups. Nodule sizes ranged from 2 mm to 28 mm and were similar between groups. Twenty-nine patients (63%) were male, with mean (standard deviation) age of 61 (11) years. Adverse events were classified using standard criteria. Patients were followed for up to 90 days, and the clinical outcomes were compared. RESULTS: Successful resection of nodules was achieved in all patients. Twelve cases of displacement of the hook wire were observed compared to only 1 in the coil group (P < .01). The total complication rate was lower in the coil group (25% vs 54%, P = .04). Two patients required transition to thoracotomy in the hook wire group, compared to none in the coil group. Median blood loss was similar in both groups (median loss, 20-22 mL). One patient had positive margins in the hook wire group. There was a nonsignificant trend toward longer hospital stay and higher major complication rates after hook wire localization (P = .4). CONCLUSIONS: Pulmonary nodule localization with coils prior to VATS resection demonstrated fewer displacements and fewer perioperative complications compared to hook wires.

Minilaparotomy-Assisted Transmesenteric-Transjugular Intrahepatic Portosystemic Shunt: Comparison with Conventional Transjugular Approach.

PURPOSE: This study was performed to compare the intrahepatic shunt function outcome and procedural complications of minilaparotomy-assisted transmesenteric (MAT)-transjugular intrahepatic portosystemic shunt (TIPS) placement with the conventional transjugular method. METHODS: This is a retrospective review of all patients who had a MAT or conventional TIPS procedure over a 6-year period at our institute. The primary patency rate, fluoroscopy time, technical success, major procedure-related complications, and mortality data were compared between two treatment groups. RESULTS: We included 49 patients with MAT-TIPS, and 63 with conventional TIPS, with an average follow-up of 21.43 months. The primary patency rates at 6 and 12 months were 82.9 and 66.7 % in the conventional TIPS group, and 81.0 and 76.5 % in the MAT-TIPS group (p = 1.000, and 0.529), respectively. There was no significant difference in technical success rate, post-procedure portosystemic pressure gradient, fluoroscopy time, and peri-procedural mortality rate between treatment groups. Major procedural-related complications were seen more frequently among MAT-TIPS patients (p = 0.012). In the MAT-TIPS group, 5 (10.2 %) patients developed post-procedure minilaparotomy, wound-related complications, and 5 (10.2 %) developed bacterial peritonitis; whereas, none of patients with conventional TIPS had either of these complications (p = 0.014). CONCLUSION: While both MAT-TIPS and conventional TIPS had similar shunt primary patency rate and technical success rate, the MAT approach was associated with a significantly higher rate of minilaparotomy-related wound complications or infectious complications. These complications maybe prevented by a change in post-procedure monitoring and therapy.

Calibrated bioresorbable microspheres: a preliminary study on the level of occlusion and arterial distribution in a rabbit kidney model.

PURPOSE: To assess the level of occlusion and arterial distribution of calibrated bioresorbable microspheres (BRMS-I and BRMS-II) compared with tris-acryl gelatin microspheres (TGMS) after renal embolization. MATERIALS AND METHODS: Six rabbits underwent renal embolization with 100-300 µm BRMS-I and TGMS; three rabbits received partial occlusion (group 1, n = 3), and three rabbits received total occlusion (group 2, n = 3). Four other rabbits received 100-300 µm BRMS-II (with higher cross-linking density than BRMS-I) in the left kidneys reaching total occlusion (group 3, n = 4). Coronal sections of the kidneys were histologically analyzed. Ease of injection, microsphere deformation, vessel sizes, and arterial distribution were assessed. RESULTS: The injection of BRMS-I, BRMS-II, and TGMS through microcatheters went smoothly without any clogging. In group 1, BRMS identification was easier than TGMS. In group 2, both BRMS-I and TGMS were observed in all three arterial levels (interlobar, arcuate, and interlobular arteries) without a significant difference (P = .84). BRMS-I were not significantly different from TGMS in the mean diameter of vessels occluded (197 µm ± 23 vs 158 µm ± 21, P = .25) or the microsphere deformation (8.85% ± 0.53% vs 11.80% ± 0.64%, P = .071). In group 3, the arterial distribution of BRMS-II was significantly different from BRMS-I and TGMS (P < .0001). CONCLUSIONS: In occluding arteries, 100-300 µm BRMS-I were not significantly different from 100-300 µm TGMS. Arterial distribution of BRMS can be influenced by their cross-linking density.