Comparison of Hemostatic Durability between N-Butyl Cyanoacrylate and Gelatin Sponge Particles in Transcatheter Arterial Embolization for Acute Arterial Hemorrhage in a Coagulopathic Condition in a Swine Model

Prostate artery embolization using n-butyl cyanoacrylate glue for symptomatic benign prostatic hyperplasia: A six-month outcome analysis in 103 patients

PURPOSE

The purpose of this study was to assess the feasibility, safety, and 6-month outcomes of prostate artery embolization (PAE) using N-butyl-cyanoacrylate (NBCA) glue as the only embolic agent in patients with benign prostatic hyperplasia (BPH)-related lower urinary tract symptoms.

MATERIALS AND METHODS

Patients with BPH-related lower urinary tract symptoms who were treated by PAE using methacryloxysulfolane-NBCA mixed with ethiodized oil (1:8 ratio) between September 2018 and January 2023 were retrospectively included. Vascular mapping was made using cone-beam computed tomography angiography. PAEs were performed as an outpatient procedure, under local anaesthesia. Outcomes were assessed at six months using the International Prostate Symptoms Score (IPSS) and associated quality-of-life score (IPSS-QoL), prostate-specific antigen (PSA) level, prostate volume, and International Index of Erectile Function form 5 (IIEF5).

RESULTS

A total of 103 men with a mean age of 68.4 ± 6 (standard deviation [SD]) years were included. Technical success rate was 100%. The mean fluoroscopy time was 26.4 ± 12.5 (SD) min and the median radiation dose was 23 980 mGy·cm (Q1, Q3: 16 770, 38 450). Compared to baseline, statistically significant improvements were observed at six months for the IPSS (8.9 ± 6.2 [SD] vs. 20.2 ± 6.5 [SD]; P = 0.01), IPSS-QoL (2.1 ± 1.4 [SD] vs. 5.1 ± 0.9 [SD]; P = 0.01), PSA level (3.6 ± 3.2 [SD] ng/mL vs. 4.8 ± 4.2 [SD] ng/mL; P = 0.0001), and prostate volume (78.6 ± 43.5 [SD] mL vs. 119.1 ± 65.7 [SD] mL; P = 0.01). Minor adverse events developed in 19/103 (18.4%) patients. No major complications occurred. Compared to baseline, the IIEF5 did not change significantly at six months (15.3 ± 6.8 [SD] vs. 15.8 ± 6.8 [SD]; P = 0.078).

CONCLUSION

PAE with NBCA is a feasible and safe method that provides good outcomes at six months in patients with BPH-related lower urinary tract symptoms. This method deserves further evaluation in randomized trials with longer follow-up.

Feasibility of the Glue-in-Plug Technique Using a Novel Liquid Embolic Material in a Swine Model

PURPOSE

To evaluate the feasibility of the glue-in-plug (GIP) technique using n-butyl-2-cyanoacrylate‒Lipiodol (NL)-iopamidol (NLI) for short-segment embolization in swine.

MATERIALS AND METHODS

The renal arteries, left external iliac artery, subclavian arteries, and common carotid arteries were each embolized in 4 swine using the GIP technique under general anesthesia. First, a type I Amplatzer vascular plug (AVP) (1-2 times the target vessel diameter) was deployed in the target artery. Next, the AVP was filled with NL mixture prepared at a ratio of 1:2 (NL12) (n = 11) or with NLI mixture prepared at a ratio of 2:3:1 (NLI231) (n = 11). Angiography was performed before, immediately after, and 1 hour after embolization to assess embolization and migration of the embolic materials. The embolized arteries were also evaluated histopathologically.

RESULTS

The migration distance of the embolic material beyond the plug tip was significantly shorter in the NLI231 group than in the NL12 group immediately after embolization (6.5 mm ± 4.5 vs 1.0 mm ± 1.8, P = .0024) and 1 hour after embolization (8.4 mm ± 5.6 vs 1.0 mm ± 1.8, P = .0013). Angiography revealed no sign of recanalization of the target vessels in any artery in either group. Mild inflammatory cell infiltration was observed around the arterial wall at the embolization site in all arteries in both groups.

CONCLUSIONS

The GIP technique using NLI231 may be a feasible procedure for short-segment embolization based on these short-term results.

Iodixanol as a New Contrast Agent for Cyanoacrylate Embolization: A Preliminary In Vivo Swine Study

N-butyl cyanoacrylate (NBCA) is a lipophilic, permanent embolic glue that must be opacified for fluoroscopic guidance. Empirically, lipophilic Lipiodol Ultra Fluid® (LUF) has been added to produce a single-phase physically stable mixture. Varying the dilution ratio allows control of glue polymerization kinetics. LUF is far more costly than water-soluble iodinated contrast agents (ICAs). Our purpose was to evaluate whether a water-soluble nonionic iso-osmolar ICA could be used instead. We embolized both renal arteries of six swine using 1:3 NBCA-LUF or NBCA-iodixanol in 1:1, 1:3, and 1:7 ratios. We used both micro-computed tomography to assess the distality of glue penetration and indexed cast ratio and histology to assess distality, arterial obliteration, vessel-wall damage, and renal-parenchyma necrosis. Glue-LUF produced significantly greater indexed cast ratio and renal-artery ROI values and a significantly shorter cast-to-capsule distance. The injected volume was significantly greater with 1:7 iodixanol than with the other mixtures. No significant differences were found for histological evidence of artery obliteration, vessel-wall damage, or renal-parenchyma necrosis. This is the first study dealing with ICA alone as a contrast agent for cyanoacrylate embolization, compared to LUF. More research is needed to determine whether water-soluble nonionic iodinated agents can be used for human NBCA embolization given the good safety profile, availability, and low cost of ICA.

Endovascular Treatment of Visceral Artery Pseudoaneurysms with Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs)

Background and Objectives: Treatment of visceral artery pseudoaneurysms (VAPs) is always indicated regardless of their diameters, as their risk of rupture is significantly higher than that of visceral artery aneurysms. The invasiveness of surgery and its associated complications have led to a shift in favor of radiological interventions as the initial treatment of choice. However, there are still some unanswered questions on endovascular treatment of VAPs regarding the optimal endovascular technique and the efficacy and safety outcomes. The purpose of this multicenter study was to retrospectively evaluate the effectiveness and safety of endovascular treatment of visceral pseudoaneurysms using Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs). Materials and Methods: Consecutive patients who underwent endovascular embolization with EVOH-based NALEAs for visceral artery pseudoaneurysms between January 2018 and June 2023 were retrospectively evaluated. Results: 38 embolizations were performed. Technical success was achieved in all patients. The clinical success rate was high (92.1% overall), with no significant differences between ruptured and unruptured VAPs (p = 0.679). Seven patients (18.4%) experienced procedure-related complications, related to one case of non-target embolization, four splenic abscesses due to end-organ infarction, and two femoral pseudoaneurysms. The rates of procedure-related complications, end-organ infarction, and vascular access-site complications did not significantly differ between ruptured and unruptured VAPs (p > 0.05). Conclusions: Both ruptured and unruptured visceral pseudoaneurysms can be effectively and safely treated with NALEA-based endovascular embolization. We suggest considering the use of NALEAs, particularly in specific clinical cases that highlight their advantages, including patients with coagulopathy, fragile vessels, and embolization targets that are located at a considerable distance from the microcatheter tip and are otherwise difficult to reach.

Transcatheter Arterial Embolization for Bleeding Related to Pelvic Trauma: Comparison of Technical and Clinical Results between Hemodynamically Stable and Unstable Patients

BACKGROUND

Endovascular intervention is now the primary line of therapy for arterial injury brought on by pelvic trauma since it can significantly reduce considerable morbidity associated with surgery and can swiftly access and control bleeding sites. Despite international guidelines and widespread awareness of the role of angioembolization in clinical practice, robust evidence comparing the outcomes of angioembolization in hemodynamically stable and unstable patients is still lacking. This study aims to directly compare the outcomes of angioembolization for the treatment of pelvic traumatic arterial injury in patients with hemodynamic stability vs. hemodynamic instability.

METHODS

In our multicenter retrospective investigation, we analyzed data from consecutive patients who underwent, from January 2020 to May 2023, angioembolization for traumatic pelvic arterial injury.

RESULTS

In total, 116 angioembolizations were performed. Gelatin sponges (56.9%) and coils (25.9%) were the most widely used embolic agents. The technical and clinical success rates were 100% and 91.4%, respectively. No statistically significant differences were observed between the two groups in terms of technical success, clinical success, procedure-related complication rate, or 30-day bleeding-related mortality.

CONCLUSIONS

Angioembolization is an effective and safe option for the management of traumatic pelvic arterial lesions even in hemodynamically unstable patients, despite technical variations such as greater use of prophylactic angioembolization.

A Multicenter Retrospective Cohort Study Evaluating the Clinical Outcomes of Patients with Coagulopathy Undergoing Transcatheter Arterial Embolization (TAE) for Acute Non-Neurovascular Bleeding

Background and Objectives: Transcatheter arterial embolization (TAE) is the mainstay of treatment for acute major hemorrhage, even in patients with coagulopathy and spontaneous bleeding. Coagulopathy is associated with worsening bleeding severity and higher mortality and clinical failure rates. Furthermore, some unanswered questions remain, such as the definition of coagulopathy, the indication for TAE or conservative treatment, and the choice of embolic agent. This study aims to assess the efficacy and safety of TAE for spontaneous non-neurovascular acute bleeding in patients with coagulopathy. Materials and Methods: This study is a multicenter analysis of retrospectively collected data of consecutive patients with coagulopathy who had undergone, from January 2018 to May 2023, transcatheter arterial embolization for the management of spontaneous hemorrhages. Results: During the study interval (January 2018-May 2023), 120 patients with coagulopathy underwent TAE for spontaneous non-neurovascular acute bleeding. The abdominal wall was the most common bleeding site (72.5%). The most commonly used embolic agent was polyvinyl alcohol (PVA) particles or microspheres (25.0%), whereas coils and gelatin sponge together accounted for 32.5% of the embolic agents used. Technical success was achieved in all cases, with a 92.5% clinical success rate related to 9 cases of rebleeding. Complications were recorded in 12 (10%) patients. Clinical success was significantly better in the group of patients who underwent correction of the coagulopathy within 24 h of TAE. Conclusions: Transcatheter arterial embolization (TAE) is effective and safe for the management of acute non-neurovascular bleeding in patients with coagulopathy. Correction of coagulopathy should not delay TAE and vice versa, as better clinical outcomes were noted in the subgroup of patients undergoing correction of coagulopathy within 24 h of TAE.

Transcatheter Arterial Embolization (TAE) in the Management of Bleeding in the COVID-19 Patient

Background and Objectives: Increasing attention is being paid to the coagulation disorders associated with SARS-CoV-2 infection. Bleeding accounts for 3-6% of COVID-19 patient deaths, and is often a forgotten part of the disease. The bleeding risk is enhanced by several factors, including spontaneous heparin-induced thrombocytopenia, thrombocytopenia, the hyperfibrinolytic state, the consumption of coagulation factors, and thromboprophylaxis with anticoagulants. This study aims to assess the efficacy and safety of TAE in the management of bleeding in COVID-19 patients. Materials and Methods: This multicenter retrospective study analyzes data from COVID-19 patients subjected to transcatheter arterial embolization for the management of bleeding from February 2020 to January 2023. Results: Transcatheter arterial embolization was performed in 73 COVID-19 patients for acute non-neurovascular bleeding during the study interval (February 2020-January 2023). Coagulopathy was observed in forty-four (60.3%) patients. The primary cause of bleeding was spontaneous soft tissue hematoma (63%). A 100% technical success rate was recorded; six cases of rebleeding resulted in a 91.8% clinical success rate. No cases of non-target embolization were observed. Complications were recorded in 13 (17.8%) patients. The efficacy and safety endpoints did not differ significantly between the coagulopathy and non-coagulopathy groups. Conclusions: Transcatheter Arterial Embolization (TAE) is an effective, safe and potentially life-saving option for the management of acute non-neurovascular bleeding in COVID-19 patients. This approach is effective and safe even in the subgroup of COVID-19 patients with coagulopathy.

Liquid Embolic Agents for Endovascular Embolization: A Review

Endovascular embolization (EE) has been used for the treatment of blood vessel abnormalities, including aneurysms, AVMs, tumors, etc. The aim of this process is to occlude the affected vessel using biocompatible embolic agents. Two types of embolic agents, solid and liquid, are used for endovascular embolization. Liquid embolic agents are usually injectable and delivered into the vascular malformation sites using a catheter guided by X-ray imaging (i.e., angiography). After injection, the liquid embolic agent transforms into a solid implant in situ based on a variety of mechanisms, including polymerization, precipitation, and cross-linking, through ionic or thermal process. Until now, several polymers have been designed successfully for the development of liquid embolic agents. Both natural and synthetic polymers have been used for this purpose. In this review, we discuss embolization procedures with liquid embolic agents in different clinical applications, as well as in pre-clinical research studies.

Efficacy and Safety of Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs) in Transcatheter Arterial Embolization (TAE) of Acute Non-Neurovascular Bleeding: A Multicenter Retrospective Cohort Study

Background and Objectives: Transcatheter arterial embolization (TAE) is part of the daily practice of most interventional radiologists worldwide. The ideal liquid embolic agent is far from being identified. Non-adhesive liquid embolic agents (NALEA) harden from the outside to the inside, resulting in deep penetration, known as "magma-like" progression, which permits a more distal embolization with good control of the embolic material. This multicenter retrospective cohort study aims to assess the efficacy, feasibility and safety of transcatheter arterial embolization (TAE) with ethylene-vinyl alcohol (EVOH)-based NALEAs (Onyx and Squid) in acute bleeding outside of the neurovascular area. Materials and Methods: This study is a multicenter analysis of retrospectively collected data of consecutive patients who had undergone, from January 2015 to December 2022, transcatheter arterial embolization with non-adhesive EVOH-based agents in the setting of acute non-neurovascular bleeding. Results: Fifty-three patients underwent transcatheter arterial embolization for acute non-neurovascular bleeding. Eight (15.1%) procedures were performed in patients with coagulopathy. The most used concentration of EVOH-based NALEAs was 34 (i.e., 8%), with a mean dose of 0.5 (±0.3) mL. The mean CT-to-groin time, the mean procedure time, the mean CT-to-embolization time and the mean fluoroscopy time were 22.9 (±12.4) min, 27.5 (±7) min, 50.3 (±13.1) min and 7.5 (±2.8) min, respectively. Technical success was achieved in all cases with a 96.2% clinical success rate. Complications were recorded in six (11.3%) patients. No statistically significant differences were observed between the group of patients with coagulopathy and the group of patients without coagulopathy in terms of efficacy and safety endpoints. Conclusions: Transcatheter arterial embolization (TAE) performed with non-adhesive EVOH-based embolic agents is an effective, feasible and safe strategy for the management of acute non-neurovascular bleeding, even in the subgroup of patients with coagulopathy.

Silk-elastinlike protein-based hydrogels for drug delivery and embolization

Silk-Elastinlike Protein-Based Polymers (SELPs) can form thermoresponsive hydrogels that allow for the generation of in-situ drug delivery matrices. They are produced by recombinant techniques, enabling exact control of monomer sequence and polymer length. In aqueous solutions SELP strands form physical crosslinks as a function of temperature increase without the addition of crosslinking agents. Gelation kinetics, modulus of elasticity, pore size, drug release, biorecognition, and biodegradation of SELP hydrogels can be controlled by placement of amino acid residues at strategic locations in the polymer backbone. SELP hydrogels have been investigated for delivery of a variety of bioactive agents including small molecular weight drugs and fluorescent probes, oligomers of glycosaminoglycans, polymeric macromolecules, proteins, plasmid DNA, and viral gene delivery systems. In this review we provide a background for use of SELPs in matrix-mediated delivery and summarize recent investigations of SELP hydrogels for controlled delivery of bioactive agents as well as their use as liquid embolics.

Comparison of n-butyl-2-cyanoacrylate and polyvinyl alcohol particles for bronchial artery embolisation in primary lung cancer: a retrospective cohort study

BACKGROUND

Bronchial artery embolisation (BAE) is an effective treatment option to control haemoptysis in primary lung cancer. However, no studies have investigated optimal embolisation material for BAE in lung cancer patients. Thus, this study aimed to compare the safety and efficacy of BAE performed using n-butyl-2-cyanoacrylate (NBCA) and polyvinyl alcohol (PVA) particles in primary lung cancer patients to determine which embolic material is better for patients with haemoptysis.

METHODS

This retrospective study was approved by the institutional review board, and consent was waived. The rates of hemostasis, complications, procedure time, dose-area product, and haemoptysis-free survival were retrospectively compared between primary lung cancer (non-small cell [n = 111] and small cell [n = 11]) patients who underwent BAE using NBCA (n = 58) or PVA particles (n = 64) between January 2004 and December 2019. Predictors of recurrent haemoptysis were analysed using the Cox proportional hazard regression model.

RESULTS

Among 122 patients (mean age, 66 ± 10 years; range 32-86 years; 103 men), more patients in the NBCA group (81.0%; 47 of 58) achieved complete hemostasis than did patients in the PVA group (53.1%; 34 of 64) (P = 0.002). No major complications were observed in either group. The procedure time (36.4 ± 21.6 vs. 56.3 ± 27.4 min, P < 0.001) was shorter, and the dose-area product (58.6 ± 64.0 vs. 233.5 ± 225.0 Gy*cm², P < 0.001) was smaller in the NBCA group than in the PVA group. The median haemoptysis-free survival was 173.0 in the NBCA group compared with 20.0 days in the PVA group (P < 0.001). The PVA use (P < 0.001) and coagulopathy (P = 0.014) were independent predictors of shortened haemoptysis-free survival.

CONCLUSION

BAE using NBCA showed significantly superior initial hemostasis with longer haemoptysis-free survival, shorter procedure time, and reduced radiation dose than BAE using PVA particles. The PVA use and coagulopathy were independent predictors of recurrent haemoptysis.

TRIAL REGISTRATION

Retrospectively registered.

Emerging Polymer Materials in Trackable Endovascular Embolization and Cell Delivery: From Hype to Hope

Minimally invasive endovascular embolization is a widely used clinical technique used for the occlusion of blood vessels to treat various diseases. Different occlusive agents ranging from gelatin foam to synthetic polymers such as poly(vinyl alcohol) (PVA) have been commercially used for embolization. However, these agents have some drawbacks, such as undesired toxicity and unintended and uncontrolled occlusion. To overcome these issues, several polymer-based embolic systems are under investigation including biocompatible and biodegradable microspheres, gelling liquid embolic with controlled occlusive features, and trackable microspheres with enhanced safety profiles. This review aims to summarize recent advances in current and emerging polymeric materials as embolization agents with varying material architectures. Furthermore, this review also explores the potential of combining injectable embolic agents and cell therapy to achieve more effective embolization with the promise of outstanding results in treating various devastating diseases. Finally, limitations and challenges in developing next-generation multifunctional embolic agents are discussed to promote advancement in this emerging field.

Surgical management of auricular arteriovenous malformations: A literature review

Auricular arteriovenous malformations (AVMs) can cause a variety of symptoms that seriously impact the patient's appearance, life, and mental well‐being. Surgery is the primary management method for auricular AVMs, but there is no consensus on how to surgically manage auricular AVMs. In this article, we document a comprehensive review of the characteristics, classification, and surgical interventions to treat auricular AVMs.

A preliminary animal study of thermal rheology fluid as a new temperature-dependent liquid intravascular embolic material

Purpose

Thermal rheology (TR) fluid, which comprises polyethylene (PE) particles, their dispersant, and solvent, is a material that increases in viscosity to various degrees depending on the type and ratio of these constituents when its temperature rises. The viscosity of type 1 (TRF-1) increases more than that of type 2 (TRF-2) near rabbit body temperature. This preliminary animal study aimed to determine the basic characteristics and embolic effect of TR fluid by comparing TRF-1 and TRF-2.

Materials and methods

Twenty-four Japanese white rabbits underwent unilateral renal artery embolization using TRF-1 or TRF-2 and follow-up angiography at 7 or 28 days (4 subgroups, n = 6 each). Subsequently, the rabbits were euthanized, and the embolized kidneys were removed for pathological examination. The primary and final embolization rates were defined as the ratio of renal artery area not visible immediately after embolization and follow-up angiography, respectively, to visualized renal artery area before embolization. The final embolization rate and maximum vessel diameter filled with PE particles were compared between materials. Moreover, the embolic effect was determined to be persistent when a two-sided 95% confidence interval (CI) for the difference in means between the embolization rates was < 5%.

Results

The final embolization rate was significantly higher for the TRF-1 than for the TRF-2 at both 7 (mean 80.7% [SD 18.7] vs. 28.4% [19.9], p = 0.001) and 28 days (94.0% [3.5] vs. 37.8% [15.5], p < 0.001). The maximum occluded vessel diameter was significantly larger for TRF-1 than for TRF-2 (870 µm [417] vs. 270 µm [163], p < 0.001). The embolic effect of TRF-1 was persistent until 28 days (difference between rates − 3.3 [95% CI − 10.0–3.4]).

Conclusion

The embolic effect of TRF-1 was more persistent than that of TRF-2, and the persistency depended on the type and ratio of TR fluid constituents.

Endovascular Use of Cyanoacrylate-Lipiodol Mixture for Peripheral Embolization: Properties, Techniques, Pitfalls, and Applications

Endovascular embolization agents are particles and fluids that can be released into the bloodstream through a catheter to mechanically and/or biologically occlude a target vessel, either temporarily or permanently. Vascular embolization agents are available as solids, liquids, and suspensions. Although liquid adhesives (glues) have been used as embolic agents for decades, experience with them for peripheral applications is generally limited. Cyanoacrylates are the main liquid adhesives used for endovascular interventions and have a major role in managing vascular abnormalities, bleeding, and many vascular diseases. They can only be injected as a mixture with ethiodized oil, which provides radiopacity and modulates the polymerization rate. This review describes the characteristics, properties, mechanisms of action, modalities of use, and indications of the cyanoacrylate-Lipiodol® combination for peripheral embolization.

In Vivo Experimental Endovascular Uses of Cyanoacrylate in Non-Modified Arteries: A Systematic Review

Cyanoacrylates were first used for medical purposes during World War II to close skin wounds. Over time, medical applications were developed, specifically in the vascular field. Uses now range from extravascular instillation in vascular grafting to intravascular injection for embolization. These applications were made possible by the conduct of numerous preclinical studies involving a variety of tests and outcome measures, including angiographic and histological criteria. Cyanoacrylates were first harshly criticized by vascular surgeons, chiefly due to their fast and irreversible polymerization. Over the past five years, however, cyanoacrylates have earned an established place in endovascular interventional radiology. Given the irreversible effects of cyanoacrylates, studies in animal models are ethically acceptable only if supported by reliable preliminary data. Many animal studies of cyanoacrylates involved the experimental creation of aneurysms or arteriovenous fistulas, whose treatment by endovascular embolization was then assessed. In clinical practice, however, injection into non-modified arteries may be desirable, for instance, to deprive a tumor of its vascular supply. To help investigators in this field select the animal models and procedures that are most appropriate for their objectives, we have reviewed all published in vivo animal studies that involved the injection of cyanoacrylates into non-modified arteries to discuss their main characteristics and endpoints.

Haemostatic materials for wound healing applications

Wounds are one of the most common health issues, and the cost of wound care and healing has continued to increase over the past decade. The first step in wound healing is haemostasis, and the development of haemostatic materials that aid wound healing has accelerated in the past 5 years. Numerous haemostatic materials have been fabricated, composed of different active components (including natural polymers, synthetic polymers, silicon-based materials and metal-containing materials) and in various forms (including sponges, hydrogels, nanofibres and particles). In this Review, we provide an overview of haemostatic materials in wound healing, focusing on their chemical design and operation. We describe the physiological process of haemostasis to elucidate the principles that underpin the design of haemostatic wound dressings. We also highlight the advantages and limitations of the different active components and forms of haemostatic materials. The main challenges and future directions in the development of haemostatic materials for wound healing are proposed.

Effects of temperature alteration on viscosity, polymerization, and in-vivo arterial distribution of N-butyl cyanoacrylate-iodized oil mixtures

PURPOSE

Temperature alteration can modify the polymerization of n-butyl cyanoacrylate (NBCA)-iodized oil mixtures during vascular embolization; its effects on viscosity, polymerization time, and intra-arterial distribution of the NBCA-iodized oil mixture were investigated.

MATERIALS AND METHODS

In vitro, the viscosities of NBCA, iodized oil, and NBCA-iodized oil mixtures (ratio, 1:1-8) were measured at 4-60 ºC using a rotational rheometer. The polymerization times (from contact with blood plasma to stasis) were recorded at 0-60 ºC using a high-speed video camera. In vivo, the 1:2 mixture was injected into rabbit renal arteries at 0, 20, and 60 ºC; intra-arterial distribution of the mixture was pathologically evaluated.

RESULTS

The mixtures' viscosities decreased as temperature increased; those at 60 ºC were almost four to five times lower than those at 4 ºC. The polymerization time of NBCA and the 1:1-4 mixtures increased as temperature decreased in the 0-30 ºC range; the degree of time prolongation increased as the percentage of iodized oil decreased. The 0 ºC group demonstrated distributions of the mixture within more peripheral arterial branches than the 20 and 60 ºC groups.

CONCLUSION

Warming reduces the mixture's viscosity; cooling prolongs polymerization. Both can be potential factors to improve the handling of NBCA-iodized oil mixtures for lesions requiring peripheral delivery. Temperature alteration influences the polymerization time, viscosity, and intra-arterial distribution of NBCA-iodized oil mixtures. Warming reduces the viscosity of the mixture, while cooling prolongs polymerization.

Feasibility and Safety of n-Butyl Cyanoacrylate-Lipiodol-Iopamidol as an Alternative Liquid Embolic Material

PURPOSE

To evaluate the feasibility and safety of n-butyl cyanoacrylate (NBCA)-Lipiodol-Iopamidol (NLI) as a liquid embolic material.

MATERIALS AND METHODS

In vitro, the ratio of NLI components was adjusted and the configuration of the mixtures was assessed visually in saline. In vivo, 14 wide-necked aneurysms were created on the common carotid and external iliac arteries of four female swine. Under balloon occlusion, 12 aneurysms were embolized with NLI prepared at a NBCA-Lipidol-Iopamidol ratio of 2:3:1 (NLI231), and two were embolized with NBCA-Lipiodol (NL) prepared at a NBCA-Lipiodol ratio of 1:2 (NL12) as a trial group. We performed angiography to evaluate the effectiveness of embolization and adhesion of the embolic material to the balloons or microcatheters.

RESULTS

In vitro, NLI231 (33% NBCA) was considered to be the optimal ratio for aneurysm embolization based on its configuration and stability. In vivo, embolization using NLI231 was successful and no adhesion between the embolic material and the balloons or microcatheters was observed in all 12 aneurysms. Embolization with NL12 was impossible in the other two aneurysms due to leakage and adhesion of NL.

CONCLUSION

The configuration of NLI changed at each ratio. NLI231 is a feasible and safe liquid embolic material for balloon-assisted embolization of wide-necked aneurysms in swine.

Hybrid repair of isolated internal iliac artery aneurysm

The best operation method for an isolated internal iliac artery aneurysm remains controversial. We report on a repair of an isolated internal iliac artery aneurysm. A 78-year-old man was referred to our facility for treatment of a left isolated internal iliac artery aneurysm. At first, we embolized the arteries distal to the aneurysm using coils and vascular plugs. Two weeks later, we performed open surgery. We resected the aneurysm wall through a transperitoneal approach only with proximal blood flow control and without surgical exposure and clamping of the arteries distal to the aneurysm. The blood flow of the internal iliac artery distal to the aneurysm had completely ceased after embolization in the first stage, which enabled us to avoid further pelvic dissection and potential bleeding. At the 6-month follow up, the patient was well and without complaints.

Advancements in the development on new liquid embolic agents for use in therapeutic embolisation

This review covers the current state-of-the-art in the development of liquid embolics for therapeutic embolisation.

Focal change of the pancreatic texture using a direct injection mixture of N-butyl cyanoacrylate and lipiodol in the pig model: a strategy for preventing pancreatic leakage during pancreatic surgery

Purpose

A soft texture of the pancreas is one of the most important predisposing factors for a pancreatic fistula. Thus, in a porcine model, we investigated a method to harden the pancreas locally by directly injecting an artificial material.

Methods

During the laparotomy, 51 samples from 17 pigs, including 13 survival models, were randomly divided into 3 groups and either received a direct injection into the pancreas of MHL (1:4 mixture of histoacryl [n-butyl cyanoacrylate] and lipiodol) (group E) or saline (group C) or only received a pinprick into the pancreas without injecting a substance (sham). We measured the change in the pancreatic hardness after the injection using a durometer and examined the histological change of the pancreas using the fibrosis grade in the survival model.

Results

The postinjection hardness of the pancreas was significantly increased in group E compared to group C and the sham group (P < 0.001). Pathologically, all cases in group E showed a severe fibrotic change, whereas the other groups demonstrated mild to no fibrosis (P < 0.001). The fibrosis in group E was localized to the area of the injection, while the surrounding areas were preserved.

Conclusion

The direct injection of MHL could induce focal hardening and fibrotic changes in the pancreas of the porcine model.

Safety and efficacy of transcatheter embolization with Glubran®2 cyanoacrylate glue for acute arterial bleeding: a single-center experience with 104 patients

PURPOSE

To assess the efficacy and the safety of Glubran^®2 n-butyl cyanoacrylate metacryloxysulfolane (NBCA-MS) transcatheter arterial embolization (TAE) for acute arterial bleeding from varied anatomic sites and to evaluate the predictive factors associated with clinical success and 30-day mortality.

METHODS

A retrospective review of consecutive patients who underwent emergent NBCA-MS Glubran^®2 TAE between July 2014 and August 2016 was conducted. Variables including age, sex, underlying malignancy, cardiovascular comorbidities, coagulation data, systolic blood pressure, and number of red blood cells units (RBC) transfused before TAE were collected. Clinical success, 30-day mortality, and complication rates were evaluated. Prognostic factors were evaluated by uni- and multivariate logistic regression analyses for clinical success, and by uni- and bivariate analyses after adjustment by bleeding sites for 30-day mortality.

RESULTS

104 patients underwent technically successful embolization with bleeding located in muscles (n = 34, 32.7%), digestive tract (n = 28, 26.9%), and viscera (n = 42, 40.4%). Clinical success rate was 76% (n = 79) and 30-day mortality rate was 21.2% (n = 22). Clinical failure was significantly associated with mortality (p < 0.0001). A number of RBC units transfused greater than or equal to 3 were associated with poorer clinical success (p = 0.025) and higher mortality (p = 0.03). Complications (n = 4, 3.8%) requiring surgery occurred only at puncture site. No ischemic complications requiring further invasive treatment occurred. Mean TAE treatment time was 4.55 min.

CONCLUSIONS

NBCA-MS Glubran^®2 TAE is a fast, effective, and safe treatment for acute arterial bleeding whatever the bleeding site.

Availability of on-site acute vascular interventional radiology techniques performed by trained acute care specialists: A single-emergency center experience

INTRODUCTION

Comprehensive treatment of a patient in acute medicine and surgery requires the use of both surgical techniques and other treatment methods. Recently, acute vascular interventional radiology techniques (AVIRTs) have become increasingly popular, enabling adequately trained in-house experts to improve the quality of on-site care.

METHODS

After obtaining approval from our institutional ethics committee, we conducted a retrospective study of AVIRT procedures performed by acute care specialists trained in acute medicine and surgery over a 1-year period, including those conducted out of hours. Trained acute care specialists were required to be certified by the Japanese Association of Acute Medicine and to have completed at least 1 year of training as a member of the endovascular team in the radiology department of another university hospital. The study was designed to ensure that at least one of the physicians was available to perform AVIRT within 1 h of a request at any time. Femoral sheath insertion was usually performed by the resident physicians under the guidance of trained acute care specialists.

RESULTS

The study sample comprised 77 endovascular procedures for therapeutic AVIRT (trauma, n = 29, and nontrauma, n = 48) among 62 patients (mean age, 64 years; range, 9–88 years), of which 55% were male. Of the procedures, 47% were performed out of hours (trauma, 52%; and nontrauma, 44%). Three patients underwent resuscitative endovascular balloon occlusion of the aorta in the emergency room. No major device-related complications were encountered, and the overall mortality rate within 60 days was 8%. The recorded causes of death included exsanguination (n = 2), pneumonia (n = 2), sepsis (n = 1), and brain death (n = 1).

CONCLUSION

When performed by trained acute care specialists, AVIRT seems to be advantageous for acute on-site care and provides good technical success. Therefore, a standard training program should be established for acute care specialists or trauma surgeons to make these techniques a part of the standard regimen.

LEVEL OF EVIDENCE

Therapy/care management study, level V.

High-grade traumatic torso visceral injury with hemodynamic instability: effectiveness of transarterial embolization using n-butyl cyanoacrylate

Trauma patients with uncontrolled hemorrhage encountering coagulopathy are often associated with poor outcome. Recently, the concept of damage control interventional radiology, which focuses on "speedy stoppage of bleeding" by interventional radiology among trauma patients with hemodynamic instability and acute traumatic coagulopathy, was proposed as an alternative to damage control surgery. N-butyl cyanoacrylate (NBCA) has been used as a liquid embolic agent in various non-traumatic situations, where it has been shown to have a high technical success rate and low recurrent bleeding rate, especially in patients with coagulopathy. In this case, we treated a young patient with hemodynamic instability caused by a high-grade hepatic injury, who underwent arterial embolization (AE) using NBCA assisted with resuscitative endovascular balloon occlusion of the aorta and achieved successful hemostasis. A review of published works using PUBMED was carried out, and 10 published reports involving 23 trauma patients who underwent AE using NBCA were identified. Among them, only four reports involving five trauma patients with torso visceral injuries were identified. Three of five patients who were hemodynamically unstable underwent AE using NBCA, resulting in the stabilization of hemodynamics. We concluded that AE with resuscitative endovascular balloon occlusion of the aorta as a damage control interventional radiology procedure might be acceptable for the hemodynamically unstable hepatic injury, and NBCA could be one of the effective hemostatic agents for this purpose, in cases of trauma-induced coagulopathy.

Polymeric materials for embolic and chemoembolic applications

Percutaneous transcatheter embolization procedures involve the selective occlusion of blood vessels. Occlusive agents, referred to as embolics, vary in material characteristics including chemical composition, mechanical properties, and the ability to concurrently deliver drugs. Commercially available polymeric embolics range from gelatin foam to synthetic polymers such as poly(vinyl alcohol). Current systems under investigation include tunable, bioresorbable microspheres composed of chitosan or poly(ethylene glycol) derivatives, in situ gelling liquid embolics with improved safety profiles, and radiopaque embolics that are trackable in vivo. This article reviews commercially available materials used for embolization as well as polymeric materials that are under investigation.

Clinical outcome of transcatheter arterial embolization with N-butyl-2-cyanoacrylate for control of acute gastrointestinal tract bleeding

OBJECTIVE. The purpose of this article is to evaluate the clinical effectiveness of trans-catheter arterial embolization (TAE) with N-butyl-2-cyanoacrylate (NBCA), with or without other embolic materials for acute nonvariceal gastrointestinal tract bleeding, and to determine the factors associated with clinical outcomes. MATERIALS AND METHODS. TAE using NBCA only or in conjunction with other materials was performed for 102 patients (80 male and 22 female patients; mean age, 61.3 years) with acute nonvariceal gastrointestinal tract bleeding. Technical success, clinical success, and clinical factors, including age, sex, bleeding tendency, endoscopic attempts at hemostasis, number of transfusions, and bleeding causes (i.e., cancer vs noncancer), were retrospectively evaluated. Univariate and multivariable logistic regression analyses were performed to evaluate clinical factors and their ability to predict patient outcomes. Survival curves were obtained using Kaplan-Meier analyses and log-rank tests. RESULTS. There were 36 patients with cancer-related bleeding and 66 with non-cancer-related bleeding. Overall technical and clinical success rates were 100% (102/102) and 76.5% (78/102), respectively. Procedure-related complications included bowel infarction, which was noted in two patients. Recurrent bleeding and bleeding-related 30-day mortality rates were 15.7% (16/102) and 8.8% (9/102), respectively. Cancer-related bleeding increased clinical failure significantly (p = 0.003) and bleeding-related 30-day mortality with marginal significance (p = 0.05). Overall survival was poorer in patients with cancer-related bleeding. CONCLUSION. TAE with NBCA with or without other embolic agents showed high technical and clinical effectiveness in the management of acute nonvariceal gastrointestinal tract bleeding. Cancer-related bleeding was the only factor related to clinical failure, and possibly related to bleeding-related 30-day mortality.

Transcatheter arterial embolization for secondary postpartum hemorrhage: outcome in 52 patients at a single tertiary referral center

PURPOSE

To assess the safety and efficacy of transcatheter arterial embolization (TAE) for the management of secondary postpartum hemorrhage (PPH) and to determine the factors associated with the clinical outcomes.

MATERIALS AND METHODS

A retrospective analysis of 52 patients (mean age, 31.6 y; range, 25-40 y) undergoing TAE for secondary PPH was performed. Clinical data, including maternal characteristics, delivery details, embolization details, and transfusion requirements, were obtained. Univariate analyses were performed to determine the factors related to clinical outcomes.

RESULTS

The major cause of bleeding was retained placental tissue (44.2%; 23 of 52). Actively bleeding foci were observed in 25 (48.1%) patients. Technical and clinical successes were achieved in 100% and 90.4% (47 of 52) of patients, respectively. Gelatin sponge particles with (n = 10) or without (n = 38) permanent embolic materials, such as microcoils or N-butyl cyanoacrylate, were most commonly used (92.3%; 48 of 52), whereas permanent embolic materials alone were used in 7.7% (4 of 52) of patients. In five patients, embolization failed, and these patients were managed by hysterectomy (n = 3), repeat TAE (n = 1), or conservative management (n = 1). Bleeding control was eventually achieved in all five patients. No maternal risk factors were related to clinical results. The median and mean follow-up periods were 3 months and 12.6 months (range, 1-62 mo). Regular menstruation resumed in all 44 patients with available follow-up, and 5 of the patients became pregnant.

CONCLUSIONS

TAE for secondary PPH is safe and effective and showed technical and clinical success in 100% and 90.4% of patients, respectively. Approximately half of these patients showed a positive bleeding focus, and the use of permanent embolic materials was also common.

Guidelines for the use of NBCA in vascular embolization devised by the Committee of Practice Guidelines of the Japanese Society of Interventional Radiology (CGJSIR), 2012 edition

Cyanoacrylates are a group of fast-acting adhesives. They form low viscosity liquids in the monomer state and instantly polymerize to become adhesive upon contact with ionic substances. Since the 1950s, they have been used around the world for industrial and household purposes. N-butyl cyanoacrylate (NBCA) is a cyanoacrylate that is commonly used for medical care, and the closure of skin wounds with NBCA has been found to promote hemostasis. However, in Japan, the intravascular injection of NBCA is considered to be off-label use, except during the treatment of gastric varices under endoscopy. The use of NBCA in embolotherapy is considered when the target vessels cannot be cannulated superselectively, for vascular diseases that require long segments of the target vessel to be embolized, or for patients in a hypocoagulable state. NBCA-based embolotherapy can be used to treat vascular malformations, acute hemorrhaging, tumors, and venous disease. The complications associated with NBCA-based embolotherapy include tissue ischemia, hemorrhaging, systemic or local reactions, and catheter adhesion to blood vessels. NBCA is mixed with Lipiodol to make it radiopaque and to adjust its polymerization time. Since there are various technical aspects to performing NBCA-based embolotherapy safely, it should be carried out by, or with the assistance of, proficient interventional radiologists.

Successful interventional management of abdominal compartment syndrome caused by blunt liver injury with hemorrhagic diathesis

We report that a case of primary abdominal compartment syndrome (ACS), caused by blunt liver injury under the oral anticoagulation therapy, was successfully treated. Transcatheter arterial embolization (TAE) was initially selected, and the bleeding point of hepatic artery was embolized with N-Butyl Cyanoacylate (NBCA). Secondary, percutaneous catheter drainage (PCD) was performed for massive hemoperitoneum. There are some reports of ACS treated with TAE. However, combination treatment of TAE with NBCA and PCD for ACS has not been reported. Even low invasive interventional procedures may improve primary ACS if the patient has hemorrhagic diathesis or coagulopathy discouraging surgeon from laparotomy.

Guidelines on the use of gelatin sponge particles in embolotherapy

Gelatin sponge (GS) is one of the most widely used embolic agents in interventional procedures. There are four commercially available GS products in Japan; however, the endovascular use of Gelfoam and Spongel is off-label, and Gelpart can only be used for hepatic artery embolization and Serescue can only be used for hemostasis of arterial bleeding. GS has been used for a variety of clinical indications, mainly tumor embolization and stopping massive arterial bleeding. The optimal size and preparation procedure of GS particles differs slightly for each clinical indication. In addition, there is a risk of ischemic and/or infectious complications associated with GS embolization in various situations. Therefore, radiologists should be familiar with not only the preparation and handling of GS particles, but also the disadvantages and potential risks, in order to perform GS embolization safely and effectively.

Endovascular treatment of intractable bleeding from a traumatic pseudoaneurysm of the internal maxillary artery

Traumatic pseudoaneurysms of the internal maxillary artery (IMA) are rare and difficult to treat. A 58-year-old man with a traumatic pseudoaneurysm of the IMA presented with intractable nasal and oral hemorrhage during dual antiplatelet therapy. Transcatheter artery embolization with N-butyl cyanoacrylate (NBCA) completely occluded the pseudoaneurysm. Transcatheter artery embolization with NBCA is a feasible and effective treatment because of its shorter treatment time and lower incidence of recurrence.

Transcatheter arterial embolization with N-butyl cyanoacrylate for acute life-threatening gastroduodenal bleeding uncontrolled by endoscopic hemostasis

PURPOSE

To investigate the feasibility, efficacy, and safety of transcatheter arterial embolization with N-butyl cyanoacrylate (NBCA) for gastroduodenal nonvariceal bleeding uncontrolled by endoscopic hemostasis.

MATERIALS AND METHODS

Between January 2006 and December 2011, a total of 317 patients underwent emergent endoscopic therapy for nonvariceal gastroduodenal bleeding, but hemostasis was not achieved in 20 cases. Emergent surgery was performed immediately following endoscopy in two patients. Arteriography was performed in the remaining 18 patients, and embolization with NBCA was performed in 15 patients (mean age, 71.3 y) in whom the bleeding site was detected on arteriography. For embolization, NBCA was mixed with iodized oil at a ratio of 1:1.5-1:4, and no other embolic material was used in the procedure. Technical and clinical success rates, recurrent bleeding, procedural time, complications, and clinical outcomes were determined for each procedure.

RESULTS

Embolization with NBCA was technically and clinically successful in all procedures, without major complications. No patient receiving embolization with NBCA experienced recurrent bleeding or required further treatment after the one-session procedure. All patients were discharged after clinical improvement. The time between puncture of the femoral artery and completion of embolization ranged from 25 to 240 minutes (mean, 66 min), and the time between the microcatheter reaching the ultimate catheter location selected for embolization and hemostasis ranged from 142 to 550 seconds (mean, 322s).

CONCLUSIONS

In this limited series, embolization with NBCA was found to be a safe, feasible, and effective treatment for gastroduodenal arterial bleeding when endoscopic hemostasis had failed.

Successful n-butyl cyanoacrylate embolization of a spontaneous rupture of the internal mammary artery in a patient with myelodysplastic syndrome: report of a case

Hemomediastinum and hemothorax due to spontaneous internal mammary artery (IMA) rupture is extremely rare, and can be a life-threatening condition. We herein present, to the best of our knowledge, the first case of spontaneous IMA rupture complicating myelodysplastic syndrome, and the first case that was successfully treated by emergency trans-arterial embolization using n-butyl cyanoacrylate.