A case-based approach to common embolization agents used in vascular interventional radiology. AJR Am J Roentgenol. 2014;203:699-708. [PMID: 25247933 DOI: 10.2214/ajr.14.12480]

Treatment of a contained rupture of a splenic artery pseudoaneurysm with direct thrombin injection

Splenic artery pseudoaneurysm is a rare and potentially fatal condition. In the present report, we describe the case of a 50-year-old woman with chronic pancreatitis who presented with worsening abdominal pain. Computed tomography demonstrated a 3.5-cm splenic artery pseudoaneurysm of the mid-splenic artery. The patient underwent attempted endovascular repair of the pseudoaneurysm that was unsuccessful. Open conversion revealed an inaccessible splenic artery due to chronic pancreatitis that resulted in dense retroperitoneal fibrosis, and repair was achieved via direct thrombin injection under ultrasound guidance of the pseudoaneurysm and splenectomy. The patient recovered well, and computed tomography at 3 days postoperatively revealed complete thrombosis of the pseudoaneurysm.

Construction of an Injectable Composite Double-Network Hydrogel as a Liquid Embolic Agent

Conventional embolists disreputably tend to recanalization arising from the low filling ratio due to their rigidity or instability. As a result, intelligent hydrogels with a tunable modulus may meaningfully improve the therapeutic efficacy. Herein, an injectable composite double-network (CDN) hydrogel with high shear responsibility was prepared as a liquid embolic agent by cross-linking poly(vinyl alcohol) (PVA) and carboxymethyl chitosan (CMC) via dynamic covalent bonding of borate ester and benzoic-imine. A two-dimensional nanosheet, i.e., layered double hydroxide (LDH), was incorporated into the network through physical interactions which led to serious reduction of yield stress for the injection of the hydrogel and the capacity for loading therapeutic agents like indocyanine green (ICG) and doxorubicin (DOX) for the functions of photothermal therapy (PTT) and chemotherapy. The CDN hydrogel could thus be transported through a thin catheter and further in situ strengthened under physiological conditions, like in blood, by secondarily cross-linking with phosphate ions for longer degradation duration and better mechanical property. These characteristics met the requirements of arterial interventional embolization, which was demonstrated by renal embolism operation on rabbits, and meanwhile favored the inhibition of subcutaneous tumor growth on an animal model. Therefore, this work makes a breakthrough in the case of largely reducing the embolism risks, thus affording a novel generation for interventional embolization.

Prospective Study of Polytetrafluoroethylene-Covered Microplugs and Detachable Coils for Embolization of Pulmonary Arteriovenous Malformations: Technical Results, Procedure Times, and Costs

PURPOSE

To determine time to occlusion and procedure costs of embolization of pulmonary arteriovenous malformations (PAVMs) using a polytetrafluoroethylene-covered microplug compared with embolization using detachable coils.

MATERIALS AND METHODS

In this prospective study, 37 patients (mean age, 39.1 years [SD ± 17.6]) with 82 PAVMs underwent embolization with microplug or detachable coils between April 2019 and January 2023. Technical success, procedure time intervals, and costs were analyzed.

RESULTS

In 37 patients, 82 PAVMs and 101 feeding arteries were successfully treated (microplug, 64; microplug + another device, 5; detachable coils alone, 32). Time from embolic device inserted into the catheter to device deployed and time to occlusion differed significantly between microplug and detachable coil cohorts (P < .0001 for both). Embolization with ≥1 microplug had a significantly shorter occlusion time than embolization with detachable coils (median, 10.0 minutes saved per feeding artery) (P < .0001). Compared with detachable coil embolization, microplug embolization saved a median of 9.0 minutes per feeding artery (P < .0001) and reduced room cost by a median of $429 per feeding artery (P < .0001). Device costs per feeding artery did not differ significantly between microplug ($2,790) and detachable coil embolization ($3,147) (P = .87).

CONCLUSIONS

Compared with coils, microplugs had an equally high technical success rate but significant time to occlusion and room costs savings per feeding artery. Total room cost and device cost together did not differ significantly between microplugs and coils. Microplugs may be considered technically effective and at least cost-neutral for PAVM embolization where clinically appropriate.

Embolization for pediatric trauma

BACKGROUND

The management of pediatric trauma with trans-arterial embolization is uncommon, even in level 1 trauma centers; hence, there is a dearth of literature on this subject compared to the adult experience.

OBJECTIVE

To describe a single-center, level 1 trauma center experience with arterial embolization for pediatric trauma.

MATERIALS AND METHODS

A retrospective review was performed to identify demographics, transfusion requirements, pre-procedure imaging, procedural details, adverse events, and arterial embolization outcomes over a 19-year period. Twenty children (age 4.5 months to 17 years, median 13.5 years; weight 3.6 to 108 kg, median 53 kg) were included. Technical success was defined as angiographic resolution of the bleeding-related abnormality on post-embolization angiography or successful empiric embolization in the absence of an angiographic finding. Clinical success was defined as not requiring additional intervention after embolization.

RESULTS

Seventy-five percent (n=15/20) of patients required red blood cell transfusions prior to embolization with a mean volume replacement 64 ml/kg (range 12-166 ml/kg) and the median time from injury to intervention was 3 days (range 0-16 days). Technical success was achieved in 100% (20/20) of children while clinical success was achieved in 80% (n=16/20). For the 4 children (20%) with continued bleeding following initial embolization, 2 underwent repeat embolization, 1 underwent surgery, and 1 underwent repeat embolization and surgery. Mortality prior to discharge was 15% (n=3). A post-embolization mild adverse event included one groin hematoma, while a severe adverse event included one common iliac artery pseudoaneurysm requiring open surgical ligation.

CONCLUSIONS

In this single-center experience, arterial embolization for hemorrhage control in children after trauma is feasible but can be challenging and the clinical failure rate of 20% in this series reflects this complexity. Standardization of pre-embolization trauma assessment parameters and embolic techniques may improve outcomes.

Weeping sponge kidney: an unusual phenomenon that should be considered in cases of severe renal haemorrhage

AIM

To describe the clinical presentation, imaging evaluation, endovascular management, and outcomes of multifocal renal capsular haemorrhage, "weeping sponge kidney", and to identify associated risk factors and the pathophysiological mechanism behind this condition.

MATERIALS AND METHODS

This is a case series in which clinical information for each of the cases was collected retrospectively from electronic patient notes as well as the radiology information and picture archiving and communication systems.

RESULTS

Four consecutive cases were included in the series. All of the cases were treated successfully with embolisation. Three of the four patients had chronic renal failure with renal atrophy, which are patient factors that appear to be associated with multifocal renal capsular haemorrhage. Based on the procedural findings and the published literature, a pathophysiological mechanism is described to explain this condition and the relevance of the collateral arterial supply to the kidney in such cases is discussed.

CONCLUSION

Small subcapsular haematomas are usually self-limiting but in patients with renal failure, there may be an increased risk of developing a weeping sponge kidney, which can be life-threatening. The endovascular treatment for multifocal haemorrhage differs from that for a single bleeding point, especially if preservation of renal function is not a priority.

Coils embolization use for coronary procedures: Basics, indications, and techniques

The use of coils is fundamental in interventional cardiology and can be lifesaving in selected settings. Coils are classified by their materials into bare metal, fiber coated, and hydrogel coated, or by the deliverability method into, pushable or detachable coils. Coils are delivered through microcatheters and the choice of coil size is important to ensure compatibility with the inner diameter of the delivery catheter, firstly to be able to deliver and secondly to prevent the coil from being stuck and damaged. Clinically, coils are used in either acute or in elective setting. The most important acute indication is typically the sealing coronary perforation. In the elective settings, coils can be used for the treatment of certain congenital cardiac abnormalities, aneurysms, fistulas or in the treatment of arterial side branch steal syndrome after CABG. Coils must always be delivered under fluoroscopy guidance. There are some associated complications with coils that can be acute or chronic, that nictitates regular followed-up. There is a need for education, training and regular workshops with hands-on to build the experience to use coils in situations that are infrequently encountered.

Amplatzer™ Vascular Plugs for Embolisation: A 10-Year Single-Centre Retrospective Study

Our objective was to investigate the indications, effectiveness, and safety of Amplatzer™ Vascular Plugs (AVPs) in clinical practice. To retrospectively identify patients managed with AVPs at the Dijon University Hospital between January 2011 and April 2021, we searched materials vigilance registries and procedure reports. The 110 identified patients underwent 111 procedures with delivery of 202 AVPs into 118 vessels; 84% of the procedures were performed by radiologists with over 10 years' experience and 67% were scheduled. Varicocele, haemostasis, pelvic varicose veins, and arterio-venous dialysis fistulas accounted for 69% of procedures. The technical and clinical success rates were 99% and 97%, respectively. The single major complication was AVP migration in a high-flow internal iliac vein, with no residual abnormalities after successful device retrieval. Several AVPs and/or concomitant injection of coils or liquid agents were used in 80% of cases. The use of AVPs alone occurred chiefly for splenic artery embolisation in trauma patients and for collateral vein occlusion in dysfunctional arterio-venous dialysis fistulas. No cases of recanalisation occurred during the 19 ± 29 month follow-ups. Based on their good safety and effectiveness profile, AVPs deserve to be part of the therapeutic armamentarium of every interventional radiologist.

Rare case of pediatric trauma with hepatic injury managed using gel-foam embolization: a case report

Nonoperative management for hepatic injuries requires observation and supportive care in the case of hemodynamically stable patients. If there is active bleeding on presentation, hepatic artery embolization is an option to achieve hemostasis in the acute setting. Although interventional radiology procedures are well documented in adults, there is limited literature regarding these procedures in the pediatric population. In this report, we present a case of a pediatric patient who sustained blunt abdominal trauma, resulting in a grade IV liver injury. Treatment involved fluoroscopically guided right hepatic segmental arterial gel-foam embolization.

Management of a recurrent right juvenile nasopharyngeal angiofibroma using direct tumorous puncture embolisation and a subtemporal-preauricular infratemporal fossa surgical approach

A juvenile nasopharyngeal angiofibroma (JNA) is a benign vascular tumour that arises from the pterygopalatine fossa. It is seen near exclusively in young males though female cases have been reported. Symptoms are due to their high vascularity and mass effect. Commonly reported symptoms include: nasal obstruction, epistaxis and nasal discharge. The mainstay of treatment is surgical resection either via an endonasal endoscopic approach or open surgical resection. Preoperative embolisation has been shown to decrease intraoperative bleeding. Embolisation may be undertaken via a transarterial (TA) approach or, more recently, via direct tumorous puncture (DTP). Options for recurrent or residual disease may include revision surgery, radiotherapy or close clinical surveillance. The following case presentation describes the management of a recurrent JNA in an adult male using preoperative embolisation via a combination of TA and DTP embolisation and an open surgical resection via a subtemporal-preauricular infratemporal fossa approach.

Results from the First-in-Human Study of the Caterpillar™ Arterial Embolization System

PURPOSE

To assess occlusion success and adverse events associated with the use of a self-expanding device for peripheral artery embolization.

METHODS

This prospective, single-arm, feasibility study was conducted using the Caterpillar™ Arterial Embolization Device composed of opposing nitinol fibers and a flow-occluding membrane. Twenty patients (24 embolization sites) were treated at four investigational centers in New Zealand and Australia and followed for 30 days. Embolization sites included mesenteric, accessory renal, and iliac arteries and their branches. Primary outcome measures were peri-procedural occlusion confirmed by angiography and freedom from device-related serious adverse events (SAEs) at 30 days. Secondary observations included time to occlusion and assessment of adverse events.

RESULTS

Peri-procedural occlusion was 100%, and freedom from a device-related SAE was 94.7% at 30 days. One patient had abdominal bloating that required hospitalization deemed possibly related to the device or procedure. Twenty-two of 24 embolization sites were occluded with one device (91.7%). Mean procedure duration was 11.7 ± 8.6 min (device deployment time: 1.8 ± 1.0 min), and mean fluoroscopy time was 241 ± 290.7 s. All embolization sites occluded during the procedure with 62.5% occluded within three minutes and 91.6% occluded within ten minutes. No devices migrated or required re-embolization. Freedom from device- and procedure-related adverse events was 84.2%. One patient died from aortic rupture during a subsequent adjunctive abdominal aortic endovascular procedure deemed unrelated to the embolization device or procedure.

CONCLUSIONS

This first-in-human study of the Caterpillar embolization device achieved peri-procedural occlusion in all patients with a 94.7% freedom from device-related SAE at 30 days.

LEVEL OF EVIDENCE

Level 2b-prospective, multicenter, single-arm, first-in-human clinical study. Pre-specified endpoints were analyzed using descriptive statistics.

[Radiological embolization procedures in acute gastrointestinal, peritoneal and muscular hemorrhage]

BACKGROUND

Treatment of acute hemorrhage is particularly challenging due to its sudden onset and the fact that it is often life-threatening. Potential causes include bleeding ulcerations of the gastrointestinal tract or tumor bleeding, but acute bleeding can also occur spontaneously or be traumatic, iatrogenic, or inflammatory.

OBJECTIVE

To demonstrate the basic principles of catheter embolization, as well as various embolic materials and their properties.

RESULTS

Today there are a wide range of embolization materials available. Ultimately the duration and extent of the desired occlusion are decisive when selecting an embolic material. Mechanical occlusion devices, particulates, and liquid embolic agents are available.

CONCLUSION

Irrespective of the wide range of different etiologies, radiological embolization therapy is a very safe treatment option in cases of computed tomographic evidence of active hemorrhage. Ultimately, the interventionalist's comprehensive knowledge of the relevant characteristics is crucial for the success of therapy.

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.

Gelatin sponge to close a tract after large-bore transhepatic access: tips for success

Percutaneous transhepatic venous access has been utilised for numerous transcatheter cardiac procedures. Traditionally, a large transhepatic tract requires the placement of permanent occlusion devices or coils. We describe a successful closure using a simple technique (Surgifoam) without the need for metal hardware placement. Immediate hemostasis was achieved. No complications were encountered.

Recent progress in liquid embolic agents

Vascular embolization is a non-surgical procedure used to treat diseases or morbid conditions related to blood vessels, such as bleeding, arteriovenous malformation, aneurysm, and hypervascular tumors, through the intentional occlusion of blood vessels. Among various types of embolic agents that have been applied, liquid embolic agents are gaining an increasing amount of attention owing to their advantages in distal infiltration into regions where solid embolic agents cannot reach, enabling more extensive embolization. Meanwhile, recent advances in biomaterials and technologies have also contributed to the development of novel liquid embolic agents that can resolve the challenges faced while using the existing embolic materials. In this review, we briefly summarize the clinically used embolic agents and their applications, and then present selected research results that overcome the limitations of the embolic agents in use. Through this review, we suggest the required properties of liquid embolic agents that ensure efficacy, which can replace the existing agents, providing directions for the future development in this field.

Percutaneous Core Needle Biopsy: Considerations in the Pediatric Patient

Image-guided percutaneous biopsy is the cornerstone of solid tissue diagnosis. The ability to safely sample tissue in locations that previously required surgery or necessitated empiric therapy has allowed for more personalized treatment options, as well as more rapid development of novel therapeutics. In children, these same advantages are accompanied by a smaller margin for error and rapidly expanding indications. The intent of this review is to outline the role of image-guided biopsy in the management of childhood disease, how this role is changing, and the practical aspects of managing and performing pediatric biopsies.

Treatment of experimental aneurysms with a GPX embolic agent prototype: preliminary angiographic and histological results

Background

Recently, liquid embolic agents have emerged for the endovascular treatment of cerebral aneurysms. Here we describe the in vivo performance of a novel liquid embolization agent (GPX Embolic Device).

Methods

Elastase-induced aneurysms were embolized with a GPX prototype under balloon assistance. Digital subtraction angiography was performed pre-deployment and immediately after, and at 5, 10, and 30 min post-deployment in 10 rabbits and at 1 month in 8 rabbits. The early post-deployment intra-aneurysmal flow was graded as unchanged, moderately diminished, or completely absent. At 1 month the status of aneurysm occlusion was evaluated. Adhesion to catheter material and migration of GPX was assessed.

Results

The mean aneurysm neck diameter, width, and height were 3.6±1.0 mm, 3.0±0.8 mm, and 7.4±1.4 mm, respectively. The mean dome-to-neck ratio was 0.9±0.2. Complete stagnation of intra-aneurysmal flow was observed in 9 of 10 aneurysms (90%) within 30 min of device deployment. One aneurysm showed moderately diminished intra-aneurysmal flow at 30 min. At 1 month, 8 aneurysms were completely occluded. There was no evidence of GPX adhesion to the catheter material. Histologically, a leukocyte and foreign body reaction to GPX was detectable 28 days after embolization.

Conclusions

This is the first preclinical study reporting the performance of a protype version of the GPX Embolic Device in a wide-neck aneurysm model. GPX showed promising results by achieving and maintaining high rates of complete angiographic occlusion, but may induce an inflammatory reaction.

Liquid and Solid Embolic Agents in Gonadal Veins

Male varicocele and pelvic congestion syndrome (PCS) are common pathologies with high predominance in young patients, having a high impact on the quality of life and infertility. Lately, the use of different endovascular embolization techniques, with various embolizing agents, shows good technical results and clinical outcomes. With the aim of presenting the “state of the art” of endovascular techniques for the treatment of male varicocele and PCS, and to discuss the performance of the different embolic agents proposed, we conducted an extensive analysis of the relevant literature and we reported and discussed the results of original studies and previous meta-analyses, providing an updated guide on this topic to clinicians and interventional radiologists. We have also underlined the technical aspects for the benefit of those who approach this type of interventional treatment. Our review suggests promising results in both the endovascular embolic treatment of male varicocele and PCS; for varicocele, a success rate of between 70% and 100% and a recurrence rate of up to 16% is reported, while for PCS it has been found that technical success is achieved in almost all cases of endovascular treatment, with a highly variable recurrence rate based on reports. Complications are overall rather rare and are represented by periprocedural pain, migration of embolic media and vascular perforations: severe adverse events have been reported very rarely.

Superselective Vesical Artery Embolization for Intractable Hemorrhagic Cystitis Following Hematopoietic Stem Cell Transplantation: A Single-Center Retrospective Study in 26 Patients

PURPOSE

To evaluate the safety and efficacy of superselective vesical artery embolization (SVAE) in the treatment of intractable hemorrhagic cystitis (HC) following hematopoietic stem cell transplantation (HSCT).

METHODS

From January 2010 to December 2018, 26 patients with hematologic malignancy who underwent SVAE for treatment of intractable HC following HSCT were retrospectively reviewed. SVAE was performed with 300-500 μm gelatin-sponge particles initially. Technical success was defined as achieving bilateral SVAE for all the prominent vesical arteries. Therapeutic efficacy was defined as: Complete response (CR): macroscopic hematuria completely disappeared on more than 2 consecutive days after SVAE; Partial response (PR): macroscopic hematuria reduced after SVAE or briefly disappeared after SVAE but reappeared soon within 2 days; No response: no response to SVAE or hematuria aggravated after SVAE; Recurrence: macroscopic hematuria relapsed on follow-up after achieving an initial CR. Adverse events were also registered.

RESULTS

There was a mean follow-up of 11.4 months (range, 0.5-83.7). The mean interval for the onset of HC after HSCT was 39.7 ± 19.0 days, and mean duration of hematuria before embolization was 14.9 ± 15.7 days. SVAE was technically successful in all patients. After embolization, macroscopic hematuria regressed within 48 h for all patients. The mean urine erythrocyte counts dropped from 14,213.2 ± 20,999.0/uL before SVAE to 6072.9 ± 12,720.7/uL on 3d after SVAE (P = 0.002) and 3720.2 ± 8988.9/uL on 7 d after SVAE (P = 0.001), respectively. Hematuria completely disappeared prior to discharge in 23 (88.5%) patients (including 20 with one embolization and 3 with 2 embolizations) and remainder 3 patients had PR. No major procedure-related complications were noted, except for post-embolization syndrome in 8 patients, which resolved with symptomatic treatment. On follow-up monthly, hematuria recurrence was seen in 4/23 patients (17.4%) and was managed conservatively in 2 patients and with repeat embolization in the remainder 2 patients.

CONCLUSION

For fragile patients with hematologic malignancy, SVAE is safe and effective to treat HC following HSCT, even though repeat embolization may be required to achieve a sustained complete remission of the hematuria.

Preoperative embolisation of orbital solitary fibrous tumour

Solitary fibrous tumours (SFT) is an encompassing terminology comprising of tumours with proliferating CD34 positive specialised fibroblasts. Orbital SFTs are rare slowly progressive highly vascular neoplasms. Complete surgical excision is considered the mainstay treatment. Incomplete resection is a known risk factor for recurrence and malignant transformation. Recently preoperative embolisation of SFT has shown promising results in reducing the vascularity of these tumours rendering them amenable to complete surgical excision. Less than 10 cases of embolisation of orbital solitary fibrous tumours have been described in literature. Our patient underwent an attempted surgical excision elsewhere with significant intraoperative haemorrhage which precluded its complete excision. Herein, we report successful outcome in a case of hypervascular orbital SFT managed with preoperative embolisation, surgical resection and adjuvant radiotherapy along with a review of relevant literature.

Neurologic Complications of Preoperative Embolization of Spinal Metastasis: A Systemic Review of the Literature Identifying Distinct Mechanisms of Injury

BACKGROUND

Preoperative embolization of spinal metastases may improve outcomes of resection by reducing surgical blood loss and operative time. Neurologic complications are rarely reported and the mechanisms leading to injury are poorly described.

METHODS

We present 2 illustrative cases of embolization-related neurologic injury from distinct mechanisms and the findings of a systemic literature review of similar complications according to the PRISMA guidelines.

RESULTS

A 77-year-old man with a history of renal cell carcinoma presented with gait dyscoordination and arm pain/weakness. Magnetic resonance imaging showed a C7/T1 mass causing severe compression of the C7/T1 roots and spinal cord. After embolization and tumor resection/fusion, lethargy prompted imaging showing multiple posterior circulation infarcts believed to be secondary to reflux of embolic particles. A 75-year-old man with renal cell carcinoma presented with L1 level metastasis causing conus compression and experienced paraplegia after superselective particle embolization presumed to be secondary to flow disruption of the artery of Adamkiewicz. Analysis of the literature yielded 6 articles reporting instances of cranial infarction/ischemia occurring in 10 patients, 12 articles reporting spinal cord ischemia/infarction occurring in 17 patients, and 5 articles reporting symptomatic postembolization tumoral swelling in 5 patients.

CONCLUSIONS

Neurologic injury is a risk of preoperative embolization of spinal metastasis from either compromise of spinal cord vascular supply or cranial stroke from reflux of embolic particles. Postprocedural tumor swelling rarely leads to clinical deficit. Awareness of these complications and the presumed mechanisms of injury may aid clinicians in implementing interventions and in counseling patients before treatment.

Comparison of complete and near-complete endovascular embolization of hypervascular spine tumors with partial embolization

OBJECTIVE

Preoperative endovascular embolization of hypervascular spine tumors can reduce intraoperative blood loss. The extent to which subtotal embolization reduces blood loss has not been clearly established. This study aimed to elucidate a relationship between the extent of preoperative embolization and intraoperative blood loss.

METHODS

Sixty-six patients undergoing preoperative endovascular embolization and subsequent resection of hypervascular spine tumors were retrospectively reviewed. Patients were divided into 3 groups: complete embolization (n = 22), near-complete embolization (≥ 90% but < 100%; n = 22), and partial embolization (< 90%; n = 22). Intraoperative blood loss was compared between groups using one-way ANOVA with post hoc comparisons between groups.

RESULTS

The average blood loss in the complete embolization group was 1625 mL. The near-complete embolization group had an average blood loss of 2021 mL in surgery. Partial embolization was associated with a mean blood loss of 4009 mL. On one-way ANOVA, significant differences were seen across groups (F-ratio = 6.81, p = 0.002). Significant differences in intraoperative blood loss were also seen between patients undergoing complete and partial embolization (p = 0.001) and those undergoing near-complete and partial embolization (p = 0.006). Pairwise testing showed no significant difference between complete and near-complete embolization (p = 0.57). Analysis of a combined group of complete and near-complete embolization also showed a significantly decreased blood loss compared with partial embolization (p < 0.001). Patient age, tumor size, preoperative coagulation parameters, and preoperative platelet count were not significantly associated with blood loss.

CONCLUSIONS

Preoperative endovascular embolization is associated with decreased intraoperative blood loss. In this series, blood loss was significantly less in surgeries for tumors in which preoperative complete or near-complete embolization was achieved than in tumors in which preoperative embolization resulted in less than 90% reduction of tumor vascular blush. These findings suggest that there may be a critical threshold of efficacy that should be the goal of preoperative embolization.

Contemporary Management of Hepatic Trauma: What IRs Need to Know

Trauma remains one of the leading causes of death in the United States in patients younger than 45 years. Blunt trauma is most commonly a result of high-speed motor vehicular collisions or high-level fall. The liver and spleen are the most commonly injured organs, with the liver being the most commonly injured organ in adults and the spleen being the most affected in pediatric blunt trauma. Liver injuries incur a high level of morbidity and mortality mostly secondary to hemorrhage. Over the past 20 years, angiographic intervention has become a mainstay of treatment of hepatic trauma. As there is an increasing need for the interventional radiologists to embolize active hemorrhage in the setting of blunt and penetrating hepatic trauma, this article aims to review the current level of evidence and contemporary management of hepatic trauma from the perspective of interventional radiologists. Embolization techniques and associated outcome and complications are also reviewed.

Advances in Biomaterials and Technologies for Vascular Embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Percutaneous ethanol ablation of intrahepatic arterial pseudoaneurysm: A case report

Hepatic arterial pseudoaneurysm is a rare but potentially fatal condition that requires prompt management. We report a case of hepatic arterial pseudoaneurysm developed after radiofrequency ablation of a hepatocellular carcinoma. The patient was successfully treated with percutaneous absolute ethanol injection under ultrasound guidance. Follow-up studies with ultrasound and computed tomography for 2 years after treatment revealed no evidence of local recurrence of hepatocellular carcinoma and of the pseudoaneurysm.

Impact of trivalent ions on the stability and cohesion of calcium polyphosphate coacervates for embolization applications

Polyphosphates (PPs) are of interest as temporary in situ setting embolic agents for which cohesive characteristics are vital. Trivalent ions Al³⁺ and Ga³⁺ were substituted into calcium PP up to 10 mol % for two PP chain lengths (degree of polymerization, D_p 200 and 9000) and the effect on the dissolution rate of the resulting coacervate was examined. High levels of trivalent ions were found to increase the dissolution rate, especially with aluminum (Al) where the coacervate with the greatest Al content (10 mol %) and larger D_p completely dissolved within the first few hours in tris(hydroxymethyl)aminomethane buffered saline. Conversely, small amounts of trivalent ions slowed the dissolution rate of the coacervates compared to those containing calcium only. The coacervate compositions determined to have the fastest and slowest ion release were evaluated for cohesion upon injection into a simulated blood vessel using a dual lumen needle. PPs with lower trivalent content had a higher coacervate yield overall, with 5% Ga and D_p 200 yielding the smallest proportion of coacervate particulates that could be implicated in unwanted distal embolization. However, further studies are required to evaluate the formation and duration of occlusions in vivo so that the PP composition can best be tailored to meet clinical requirements. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2638-2648, 2019.

Efficacy and prognostic factors of transarterial embolization as initial treatment for spontaneously ruptured hepatocellular carcinoma: a single-center retrospective analysis in 57 patients

PURPOSE

To evaluate the efficacy and prognostic factors following transarterial embolization (TAE) as initial treatment for spontaneously ruptured hepatocellular carcinoma (HCC).

METHODS

From June 2012 to June 2016, a total of 57 spontaneously ruptured HCC patients who received TAE as initial therapy were retrospectively studied at our institution. Patients were followed until October 2016. Survival rates were estimated using the Kaplan-Meier method, and prognostic factors related to survival were evaluated using Cox regression analysis.

RESULTS

Among them, 8 (14.0%) patients died within 30 days after initial TAE. The median overall survival time was 208 days. The 6-month, 1-year, and 2-year cumulative overall survival rates were 50.3%, 35.9%, and 14.7%, respectively. Multivariate analysis indicated that tumor size [HR (hazard ratio) 1.12; 95% CI (confidence interval) 1.02-1.23, P = 0.022] Child-Pugh class (HR 1.78; 95% CI 1.13-2.80; P = 0.013), absence of shock on admission (HR 0.40; 95% CI 0.17-0.95; P = 0.039), and embolization with lipiodol and gelatin sponge particles (HR 0.33; 95% CI 0.16-0.70; P = 0.004) were independent prognostic factors for survival.

CONCLUSION

TAE appeared to be an effective initial treatment for spontaneously ruptured HCC. The results indicated that large tumors, poor Child-Pugh class, and shock on admission were associated with poor prognosis. For these patients, embolization with lipiodol and gelatin sponge particles could achieve better survival than PVA particles used.

Midterm Recanalization after Arterial Embolization Using Hydrogel-Coated Coils versus Fibered Coils in an Animal Model

PURPOSE

To compare angiographic and pathologic effects (ie, occlusion, recanalization) after embolization with Hydrogel-coated coils (HydroCoils) and fibered coils in the renal and internal iliac arteries after 7 days and 1 and 4 months in an animal model.

MATERIALS AND METHODS

Twelve sheep had 1 internal iliac and 1 renal artery randomly embolized with HydroCoils or fibered coils. Renal and internal iliac arteries were embolized with detachable 0.018-inch coils and pushable 0.035-inch coils, respectively. All animals had control angiography performed at 7 days, and 1 and 4 months to assess recanalization before euthanasia. Recanalization and inflammation were evaluated via pathologic examination.

RESULTS

At 1 month, 100% of arteries embolized with HydroCoils were occluded vs 50% of those embolized with fibered coils (P = .004). At 4 months, 80% of arteries embolized with HydroCoils were occluded vs 25% of those embolized with fibered coils (P = .01). Surface of vessel occlusion was significantly greater for iliac arteries (96.7% ± 8.9) than for renal arteries (94.2% ± 5.3; P = .0076). Surface of occlusion of the renal arteries (92.2% ± 5.1) was lower for fibered coils than for HydroCoils (96.8% ± 4.7; P = .0287). Surface percentage of thrombus was significantly lower for HydroCoils than for fibered coils (P < .0001). Surface percentage of thrombus was correlated with surface percentage of recanalization (P = .0181).

CONCLUSIONS

After 4 months, 75% of arteries embolized with fibered coils were recanalized vs 20% of those embolized with HydroCoils (P = .01). Reduced amount of thrombus after embolization with HydroCoils accounted for a reduced rate of arterial recanalization.

Preoperative arterial embolization of heterotopic ossification around the hip joint

Heterotopic ossification (HO) around the hip joint is not uncommon following neurological injury. Often, surgical treatment is performed in patients with restricted motion and/or refractory pain due to grade III or IV HO according to Brooker classification. The major complication that occurs as a result of surgical HO removal is perioperative bleeding due to hyper-vascularization of the lesion. Here, we report a case of preoperative embolization in a 51-year-old male patient presenting with restricted bilateral hip range of motion (ROM) due to HO following a spinal cord injury. In the right hip without preoperative arterial embolization, massive bleeding occurred during surgical removal of HO. Thus, the patient received a transfusion postoperatively due to decreased serum hemoglobin levels. For surgery of the left hip, preoperative embolization of the arteries supplying HO was performed. Surgical treatment was completed without bleeding complications, and the patient recovered without a postoperative transfusion. This case highlights that, while completing surgical removal for ROM improvements, orthopedic surgeons should consider preoperative arterial embolization in patients with hip HO.

Transcatheter Arterial Embolization for Postoperative Bleeding Following Abdominal Surgery

PURPOSE

We aimed to estimate the usefulness of transcatheter arterial embolization (TAE) in patients with postoperative abdominal hemorrhage and to evaluate the effects of pancreatic fistula on clinical outcomes and angiographic findings.

MATERIALS AND METHODS

We enrolled 22 patients (20 males and 2 females; mean age 63 years; range 25-86 years), who underwent transarterial angiography for postoperative hemorrhage after abdominal surgery. This group corresponded to 28 procedures. Technical and clinical success rates were calculated, and clinical findings and outcomes were compared between patients with and without a pancreatic fistula.

RESULTS

Pre-interventional CT was performed in all patients before first angiography, and the location of the bleeding was identified in all but one patient. Active arterial bleeding, identified by extravasation of contrast agent (n = 12), pseudoaneurysm formation (n = 12), and arterial wall irregularity (n = 2) were detected in 28 angiographic procedures, and embolization was performed in 26 instances. Various embolization techniques such as isolation, packing, embolization, and stentgraft implantation were performed. The technical and clinical success rates were 96% (25/26 procedures) and 82% (18/22 patients), respectively. In hemodynamically unstable patients (shock index: heart rate/systolic blood pressure > 1), a 92% (12/13 cases) technical success rate was achieved. There were no significant differences in any evaluated parameters between patients with and without pancreatic fistula.

CONCLUSION

TAE is a safe and effective for treating postoperative hemorrhage even in patients with hemodynamic instability and pancreatic fistula. Additionally, pre-interventional CT is useful for effective, consecutive interventions.

Transforming Nanofibers into Woven Nanotextiles for Vascular Application

This study investigates the unique properties, fabrication technique, and vascular applications of woven nanotextiles made from low-strength nanoyarns, which are bundles of thousands of nanofibers. An innovative robotic system was developed to meticulously interweave nanoyarns in longitudinal and transverse directions, resulting in a flexible, but strong woven product. This is the only technique for producing seamless nanotextiles in tubular form from nanofibers. The porosity and the mechanical properties of nanotextiles could be substantially tuned by altering the number of nanoyarns per unit area. Investigations of the physical and biological properties of the woven nanotextile revealed remarkable and fundamental differences from its nonwoven nanofibrous form and conventional textiles. This enhancement in the material property was attributed to the multitude of hierarchically arranged nanofibers in the woven nanotextiles. This patterned woven nanotextile architecture leads to a superhydrophilic behavior in an otherwise hydrophobic material, which in turn contributed to enhanced protein adsorption and consequent cell attachment and spreading. Short-term in vivo testing was performed, which proved that the nanotextile conduit was robust, suturable, kink proof, and nonthrombogenic and could act as an efficient embolizer when deployed into an artery.

Interventional radiology of the adrenal glands: current status

As more and more adrenal neoplasms are found incidentally or symptomatically, the need for interventional procedures has being increasing. In recent years these procedures registered continued steady expansion. Interventional radiology of the adrenal glands comprises angiographic and percutaneous procedures. They may be applied both in benign and in malignant pathologies. The present review reports the current status of indications, techniques results and complications of the image-guided procedures.

Particle embolization of systemic-to-pulmonary collateral artery networks in congenital heart disease: Technique and special considerations

Systemic-to-pulmonary artery collateral networks commonly develop in patients with single-ventricle physiology and chronic hypoxemia. Although these networks augment pulmonary blood flow, much of the flow is ineffective and contributes to cardiac volume loading. This volume loading can have detrimental effects, especially for single-ventricle patients. Some data suggest that occluding collaterals may improve outcomes after subsequent operations, especially when the volume of collateral flow is significant. Traditional practice has been to coil occlude the feeding vessel. We perform particle embolization of these collateral networks for two primary reasons. First, access to the feeding vessel is not blocked as collaterals may redevelop. Second, particles occlude the most distal connections. Thus, embolization with particles should be considered as an alternative to coil occluding the proximal feeding vessel.

An injectable shear-thinning biomaterial for endovascular embolization

Improved endovascular embolization of vascular conditions can generate better patient outcomes and minimize the need for repeat procedures. However, many embolic materials, such as metallic coils or liquid embolic agents, are associated with limitations and complications such as breakthrough bleeding, coil migration, coil compaction, recanalization, adhesion of the catheter to the embolic agent, or toxicity. Here, we engineered a shear-thinning biomaterial (STB), a nanocomposite hydrogel containing gelatin and silicate nanoplatelets, to function as an embolic agent for endovascular embolization procedures. STBs are injectable through clinical catheters and needles and have hemostatic activity comparable to metallic coils, the current gold standard. In addition, STBs withstand physiological pressures without fragmentation or displacement in elastomeric channels in vitro and in explant vessels ex vivo. In vitro experiments also indicated that STB embolization did not rely on intrinsic thrombosis as coils did for occlusion, suggesting that the biomaterial may be suitable for use in patients on anticoagulation therapy or those with coagulopathy. Using computed tomography imaging, the biomaterial was shown to fully occlude murine and porcine vasculature in vivo and remain at the site of injection without fragmentation or nontarget embolization. Given the advantages of rapid delivery, in vivo stability, and independent occlusion that does not rely on intrinsic thrombosis, STBs offer an alternative gel-based embolic agent with translational potential for endovascular embolization.

Peripheral Embolization Using Hydrogel-Coated Coils Versus Fibered Coils: Short-Term Results in an Animal Model

OBJECTIVES

To angiographically compare the occlusive effects of hydrocoils and fibered coils in the renal and internal iliac arteries at 24 h and 7 days in the sheep model. To determine the occlusive mechanism by hydrocoils and fibered coils by pathological examination.

MATERIALS AND METHODS

Two types of peripheral hydrogel-coated and fibered coils similar in diameter and length were compared. The right and left renal arteries were embolized with 0.018-inch detachable hydrocoils or fibered coils in six sheep. Then, the right and left internal iliac arteries were embolized with 0.035-inch pushable hydrocoils or fibered coils. Arterial recanalization was evaluated at 24 h and at 7 days with angiography. At pathology, the surface percentage of thrombus and embolic material (platinum, Dacron fibers and hydrogel) and the presence of inflammation were assessed.

RESULTS

No difference was found between the coils for recanalization at 24 h or 7 days. For hydrocoils, the surface of occlusion corresponded to thrombus for 42% and coil for 58% including 42% of platinum and 16% of hydrogel, respectively. For fibered coils, the surface of occlusion was composed of thrombus for 69% and of platinum and fibers for 31%. The surface percentage occupied by thrombus was significantly lower for hydrocoils than for fibered coils (p = 0.0047). The surface percentage of embolic was also different between the two products (p = 0.049). No degradation of hydrogel was found at any time points.

CONCLUSION

The percentage of thrombus was significantly less with hydrocoils as compared to fibered coils, which may account for reduced long-term recanalization.

Ophthalmic artery occlusion following neuro-embolization of the external carotid artery, a case report

BACKGROUND

Embozene® is a new neuroembolizing microsphere used to reduce intraoperative bleeding for head and neck tumours. We report a case of iatrogenic ophthalmic artery occlusion after Embozene® embolization of the external carotid artery (ECA).

CASE PRESENTATION

A 22-year-old African gentleman presented with left nasal obstruction and epistaxis for 2 years and was diagnosed with nasopharyngeal carcinoma. He subsequently underwent embolization of the maxillary branch of the left ECA using Embozene® Microspheres - 250 μm in size before endoscopic tumour excision to reduce intra-operative bleeding. He complained of sudden painless profound visual loss in the left eye (LE) two hours after embolization. Visual acuity in LE was no light perception. Fundus examination showed pale retina with no cherry red spot. Arterial narrowing and segmentation were seen in all quadrants. A diagnosis of left ophthalmic artery occlusion was made. Despite immediate management including ocular massage and lowering of intraocular pressure, the visual loss remained. Retrospective review of digital subtraction angiogram showed an anastomosis between the left ophthalmic artery and anterior deep temporal artery as a potential route for microspheres migration.

CONCLUSION

Pre-operative angio-architecture understanding and diligent selection of embolic material are helpful in preventing this adverse event. The use of newer agents for embolotherapy may cause migration of embolic material from the external to the internal carotid system leading to ophthalmic artery occlusion and blindness.

“Beyond saving lives”: Current perspectives of interventional radiology in trauma

Interventional radiology (IR) has become an integral part in the management of traumatic injuries. There is an ever-increasing role of IR in traumatic injuries of solid abdominal organs, pelvic and peripheral arteries to control active bleeding by therapeutic embolization or vascular reconstruction using stent grafts. Traditionally, these endovascular treatments have been offered to hemodynamically stable patients. However, in recent times endovascular approach has become preferable to surgery even in hemodynamically unstable patients with injury of surgically difficult-to-access sites. With shifting trends towards non operative management coupled with availability of the current state-of-the-art equipments, hardware and technical expertise, IR has gained an impeccable role in trauma management. However, due to lack of awareness and widespread acceptance, IR continues to remain an ocean of unexplored potentialities.

Interventional Radiology and Bleeding Disorders: What the Oral and Maxillofacial Surgeon Needs to Know

Endovascular techniques are essential for controlling acute head and neck bleeding that cannot be controlled by local or systemic measures. Detailed knowledge of the head and neck vascular anatomy, advances in catheterization techniques, and the availability of new embolic materials have improved the safety, efficacy, and predictability of these procedures. To improve patient safety, the oral and maxillofacial surgeon must be familiar with these techniques.

Image-guided urological interventions: What the urologists must know

Advances in imaging technology, especially in the last two decades, have led to a paradigm shift in the field of image-guided interventions in urology. While the traditional biopsy and drainage techniques are firmly established, image-based stone management and endovascular management of hematuria have evolved further. Ablative techniques for renal and prostate cancer and prostate artery embolization for benign prostatic hypertrophy have evolved into viable alternative treatments. Many urologic diseases that were earlier treated surgically are now effectively managed using minimally invasive image-guided techniques, often on a day care basis using only local anesthesia or conscious sedation. This article presents an overview of the technique and status of various image-guided urological procedures, including recent emerging techniques.