Properties of N-Butyl Cyanoacrylate–iodized Oil Mixtures for Arterial Embolization: In Vitro and In Vivo Experiments

Spontaneous retroperitoneal hematoma treated with transarterial embolization: a systematic review and metanalysis

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the safety, technical, and clinical effectiveness of percutaneous Transarterial Embolization (TAE) in treating spontaneous retroperitoneal hematomas as well as assess treatment outcomes in patients who underwent target or empirical embolization.

MATERIALS AND METHODS

Through the PubMed, Embase, and Google Scholar databases, an extensive search was performed in the fields of spontaneous retroperitoneal hematomas treated with transcatheter arterial embolization. We collected pooled data on 141 patients from 6 separate articles selected according to the inclusion and exclusion criteria.

RESULTS

Technical success rate was 100% in all six studies, for both targeted and empirical embolization. The clinical success rate varied from 56.3 to 89.5%. The total number of complications related to the embolization procedure was 10 events out of 116 procedures analyzed. Empirical or empirical embolization was performed in three studies, where the source of active bleeding was not evident during DSA. A meta-analysis compared the rebleeding rates between targeted and empirical embolization groups. The odds ratio from pooled data from the three assessed studies (72 patients) showed no significant difference in rebleeding rates after empirical TAE compared with targeted TAE.

CONCLUSIONS

TAE is a safe, effective, and potentially life-saving procedure for the treatment of life-threatening spontaneous retroperitoneal hematomas. Empirical and targeted TAE procedures demonstrate a relatively low risk of complications, compared to the high technical and relatively high clinical success rates.

Blocked-flow vs. free-flow cyanoacrylate glue embolization: Histological differences in an in vivo rabbit renal artery model

PURPOSE

The purpose of this in vivo animal study was to compare the acute histological effects on the arterial vessel wall of free-flow vs. blocked-flow embolization with metacryloxysulfolane-n‑butyl cyanoacrylate (MS-NBCA) in several concentrations.

MATERIALS AND METHODS

A total of 42 rabbit renal arteries were embolized using MS-NBCA mixed with ethiodized oil. The MS-NBCA concentration was 12.5%, 25%, or 50%. All mixtures were injected under both free-flow and blocked-flow conditions. The rabbits were euthanised 30 min after arterial embolization. Arterial-lumen distension, intimal inflammation and necrosis, peri‑arterial edema, and distality of MS-NBCA penetration were assessed histologically. Multivariable regression analyses were performed using a manual backward procedure, with linear, ordinal and logistic regression to search for factors associated with these outcomes RESULTS: Marked or severe dilatation was observed in 36 out of 42 arteries (86%) and marked or transmural intimal arteritis in all 42 arteries (42/42; 100%). Lumen dilatation caused focal vessel-wall flattening, which resulted in intimal necrosis. Multifocal necrosis extending from the intima to the media occurred in 23 out of 42 kidneys (55%) and peri‑arterial edema with multifocal vascular leakage in 19 out of 42 kidneys (45%). At multivariable analysis, blocked-flow MS-NBCA injection was associated with greater severity of vessel-wall lesions, including intimal arteritis (P = 0.003) and intimal necrosis (P = 0.014), compared to free-flow injection. Blocked-flow injection was also associated with peri‑arterial edema (P = 0.008) and greater distality of MS-NBCA penetration (P = 0.001).

CONCLUSION

Blocked-flow MS-NBCA injection during renal artery embolization is significantly associated with more acute arterial-wall damage and greater distality of glue penetration compared to free-flow injection in a rabbit model. These preliminary findings may have clinical implications, as blocked-flow injection is routinely used to treat specific vascular diseases or malformations in human.

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.

Comparison of Renal Damage Following Renal Artery Embolization with Three Different Embolic Mixtures in Swine

Purpose

Renal artery embolization is a minimally invasive and effective procedure for renal ablation, a complete necrosis of the renal parenchyma. This study aims to compare the extent of renal damage in swine following renal artery embolization with ethanol and N-butyl-2-cyanoacrylate, commonly used as embolic materials in renal ablation.

Material and Methods

Three different embolic mixtures were prepared for renal artery embolization in swine: 33% ethanol-Lipiodol mixture (ethanol:Lipiodol = 1:2; Group A), 67% ethanol-Lipiodol mixture (ethanol:Lipiodol = 2:1; Group B), and 10% N-butyl-2-cyanoacrylate-Lipiodol mixture (N-butyl-2-cyanoacrylate:Lipiodol = 1:9; Group C). Three swine were assigned to each group and underwent embolization of the unilateral renal artery. Renal arteriography was performed before, immediately after, and two days after renal artery embolization. After two days, the kidneys were removed to determine the macroscopic necrosis rate and for histologic examination. Dark tissue regions were considered necrotic.

Results

The macroscopic necrosis rate of the kidneys was 50.3%±7.4%, 100%±0%, and 100%±0% in Groups A, B, and C, respectively. The necrosis rates were higher in Groups B and C than in Group A. Histologically, the renal tubules were damaged in the necrotic areas. In addition, the glomeruli were damaged in Groups A and B but were preserved in Group C.

Conclusions

Sixty-seven percent ethanol-Lipiodol mixture and 10% N-butyl-2-cyanoacrylate-Lipiodol mixture are effective embolic materials in renal artery embolization for renal ablation in swine. Also, ethanol caused partial glomerular necrosis, whereas N-butyl-2-cyanoacrylate preserved the glomeruli. Therefore, ethanol should be used for renal ablation.

Intraarterial embolizations in life-threatening spontaneous retroperitoneal and rectus sheath hemorrhage (SRRSH): a three-center experience

PURPOSE

To retrospectively evaluate the technical and clinical success of interventional treatments employed in three University medical centers and to develop work-flow recommendations for intra-arterial embolizations in patients with life-threatening spontaneous retroperitoneal and rectus sheath hemorrhage (SRRSH).

MATERIALS AND METHODS

Retrospective evaluation of all patients with contrast-enhanced CT and digital subtraction angiography (DSA) for SRRSH from 01/2018 to 12/2022, amounted to 91 interventions in 83 patients (45f, 38m) with a mean age of 68.1 ± 13.2 years. Analysis of the amount of bleeding and embolized vessels, choice of embolization material, technical success, and 30-day mortality was performed.

RESULTS

Pre-interventional contrast-enhanced CT demonstrated active contrast extravasation in 79 cases (87%). DSA identified a mean of 1.4 ± 0.88 active bleeds in all but two interventions (98%), consisting of 60 cases with a singular and 39 cases of >1 bleeding artery, which were consecutively embolized. The majority of patients underwent embolization with either n-butyl-2-cyanoacrylate (NBCA; n=38), coils (n=21), or a combination of embolic agents (n=23). While the technical success rate was documented at 97.8%, 25 patients (30%) died within 30 days after the initial procedure, with mortality rates ranging from 25 to 86% between the centers, each following different diagnostic algorithms.

CONCLUSION

Embolotherapy is a safe therapy option with high technical success rates in patients with life-threatening SRRSH. To maximize clinical success and survival rates, we propose a standardized approach to angiography as well as a low threshold for re-angiography.

X-ray Microtomography to Assess Determinants of In Vivo N-Butyl Cyanoacrylate Glubran®2 Polymerization: A Rabbit-Model Study

Although introduced decades ago, few cyanoacrylate glues have been approved for endovascular use, despite evidence of their usefulness, notably for complex procedures suchas hemostatic embolization. Indications include massive bleeding requiring emergent hemostasis and prevention of severe bleeding during scheduled surgery to remove a hypervascular tumor. Adding radiopaque Lipiodol Ultra Fluid® (LUF) modulates glue polymerization and allows fluoroscopic guidance, but few comparative in vivo studies have assessed the impact of the resulting change in glue concentration or of other factors such as target-vessel blood flow. In a rabbit model, we used ex vivo X-ray microtomography to assess the results of in vivo renal-artery embolization by various mixtures of N-butyl cyanoacrylate (NBCA), metacryloxysulfolane, and LUF. Overall, penetration to the superficial interlobular arteries was achieved in about two-thirds of cases and into the capillaries in nearly half the cases, while cast fragmentation was seen in slightly more than half the cases. Greater NBCA dilution and the blocked-blood-flow technique were independently associated with greater distality of penetration. Blocked-blood-flow injection was independently associated with absence of fragmentation, capillary penetration, a shorter cast-to-capsule distance, and higher cast attenuation. A larger mixture volume was independently associated with higher indexed cast ratio and deeper penetration. Finally, microtomography is an adapted tool to assess ex vivo distribution of glue cast.

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.

In Vitro Evaluation of Acrylic Adhesives in Lymphatic Fluids-Influence of Glue Type and Procedural Parameters

To evaluate the embolic properties of different acrylic adhesive/iodized oil mixtures for lymphatic interventions. Polymerization of histoacryl (HA) (Bayer Healthcare) and glubran 2 (GL) (GEM) mixed with iodized oil (ratios 1:0–1:7) were investigated in lymphatic fluids with low and high triglyceride (low TG & high TG) contents. Static polymerization time and dynamic polymerization experiments with different volumes of glucose flush (1, 2 and 5 mL) were performed to simulate thoracic duct embolization. For both glues, static polymerization times were longer when the iodized oil content was increased and when performed in high TG lymphatic fluid. In the dynamic experiments, the prolongation of polymerization due to the oil content and TG levels was less pronounced for both glue types. Increased lymphatic flow rates decreased embolization times for low glue/oil ratios while preventing embolization for high glue/oil ratios. Higher glucose flush volumes increased occlusion times. Polymerization times of acrylic glue in a lymphatic fluid are prolonged by increasing the iodized oil concentration and triglyceride concentration as well as by using larger volumes of glucose flush. Increased lymphatic flow rates decrease embolization times for low glue/oil ratios and may prevent embolization for high glue/oil ratios.

Transcatheter arterial embolization for massive hemobilia with N-butyl cyanoacrylate (NBCA) Glubran 2

BACKGROUND

Massive hemobilia is a life-threatening condition and therapeutic challenge. Few studies have demonstrated the use of N-butyl cyanoacrylate (NBCA) for massive hemobilia.

PURPOSE

To investigate the efficacy and safety of transcatheter arterial embolization (TAE) using NBCA Glubran 2 for massive hemobilia.

MATERIAL AND METHODS

Between January 2012 and December 2019, the data of 26 patients (mean age 63.4 ± 12.6 years) with massive hemobilia were retrospectively evaluated for TAE using NBCA. The patients' baseline characteristics, severities of hemobilia, and imaging findings were collected. Emergent TAE was performed using 1:2-1:4 mixtures of NBCA and ethiodized oil. Technical success, clinical success, procedure-related complications, and follow-up outcomes were assessed.

RESULTS

Pre-procedure arteriography demonstrated injuries to the right hepatic artery (n = 24) and cystic artery (n = 2). Initial coil embolization distal to the lesions was required in 5 (19.2%) patients to control high blood flow and prevent end-organ damage. After a mean treatment time of 11.2 ± 5.3 min, technical success was achieved in 100% of the patients without non-target embolization and catheter adhesion. Clinical success was achieved in 25 (96.2%) patients. Major complications were noted in 1 (3.8%) patient with gallbladder necrosis. During a median follow-up time of 16.5 months (range 3-24 months), two patients died due to carcinomas, whereas none of the patients experienced recurrent hemobilia, embolic material migration, or post-embolization complications.

CONCLUSION

NBCA embolization for massive hemobilia is associated with rapid and effective hemostasis, as well as few major complications. This treatment modality may be a promising alternative to coil embolization.

Clinical Outcomes of Transcatheter Arterial Embolization Using N-butyl-2-cyanoacrylate (NBCA) in Cirrhotic Patients

Purpose

To evaluate the clinical outcomes of transcatheter arterial embolization (TAE) with n-butyl-2-cyanoacrylate (NBCA) for treatment of bleeding in cirrhotic patients.

Materials and methods

A total of 35 cirrhotic patients (26 men, 9 women; mean age, 48.4 ± 11.1) who underwent TAE with NBCA for bleeding from January 2011 to December 2020 were retrospectively analysed. Only cirrhotic patients with active arterial bleeding confirmed on computed tomography (CT) were included. Fifteen patients were hemodynamically unstable before embolization procedure, and coagulopathy was observed in 32 patients. The mean MELD score and Child Pugh score were 24 ± 9.9 and 9.9 ± 2.2, respectively. The mean haemoglobin level and mean number of RBC units transfused before embolization were 7.4 ± 1.4 g/dL and 10.2 ± 4, respectively. The technical, clinical success rate and 30-day mortality rate were evaluated.

Results

Technical success and clinical success rates were achieved in 100% and 82.8% of patients, respectively. Overall 30-day mortality rate was 48%. No major complications related to the embolization procedure was seen. Only the greater number of RBC units transfused before the embolization procedure (OR = 1.81, 95% CI = 1.17-2.80, P = 0.007) was significantly associated with clinical failure. Greater number of RBC units transfused (OR = 1.53, 95% CI: 1.00-2.34, P = 0.004) and higher Child Pugh score (OR 2.44, 95% CI 1.26-4.71, P = 0.008) were significantly associated with higher 30-day mortality rate.

Conclusion

Transcatheter arterial embolization using NBCA can be used as the effective treatment option for bleeding in cirrhotic patients which has a high technical and clinical success despite the grave prognosis associated with cirrhosis.

Treatment of a patient with carotid blowout syndrome with a new deconstructive embolization technique

Carotid blowout syndrome is a rare clinical conditions with a high mortality rate, especially in patients with head and neck tumors who have received radiotherapy and chemotherapy. We present our patient who had hemangioendothelioma of the neck for 5 years and therefore received radiotherapy, fistulized to the skin on the neck and active bleeding out of the fistula area. In the radiological imaging of the patient, vessel wall irregularities in the common carotid artery (CCA) and accompanying pseudoaneurysm with a diameter of 3 cm were detected, and endovascular treatment was performed. After the patient passed the balloon occlusion test, first the proximal internal carotid artery was closed with coils. Then, the balloon was inflated proximal to the CCA and a 10% diluted glue-lipiodol mixture was injected into the entire diseased CCA bed. Closure of the distal with coil and proximal with balloon prevented the risk of off-target embolization of the glue.

Raman Spectroscopic Characterization of Polymerization Kinetics of Cyanoacrylate Embolic Glues for Vascular Embolization

Endovascular glue embolization is a minimally invasive technique used to selectively reduce or block the blood supply to specific targeted vessels. Cyanoacrylate glues, mixed with radiopaque iodized oil, have been widely used for vascular embolization owing to their rapid polymerization rate, good penetration ability and low tissue toxicity. Nevertheless, in clinical practice, the selection of the glue–oil proportion and the manual injection process of mixtures are mostly based on empirical knowledge of operators, as the crucial physicochemical effect of polymerization kinetics has rarely been quantitatively investigated. In this study, the Raman spectroscopy is used for studying the polymerization kinetics of n-butyl-cyanoacrylate-based glues mixed with an iodized oil. To simulate the polymerization process during embolization, glue–oil mixtures upon contact with a protein ionic solution mimicking blood plasma are manually constructed and their polymerization kinetics are systematically characterized by Raman spectroscopy. The results demonstrate the feasibility of Raman spectroscopy in the characterization of polymerization kinetics of cyanoacrylate-based embolic glues. The polymerization process of cyanoacrylate-based mixtures consists of a fast polymerization phase followed by a slow phase. The propagation velocity and polymerization time primarily depend on the glue concentrations. The commonly used 50% mixture polymerizes 1 mm over ∼21.8 s, while it takes ∼51 min to extend to 5 mm. The results provide essential information for interventional radiologists to help them understand the polymerization kinetics of embolic glues and thus regulate the polymerization rate for effective 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.

Feasibility and outcomes of bronchial artery embolization in patients with non-massive hemoptysis

Purpose

To evaluate the safety, efficacy, and long-term outcome of bronchial artery embolization (BAE) in the treatment of non-massive hemoptysis and the prognostic factors associated with recurrent bleeding.

Materials and methods

From March 2005 to September 2014, BAE was performed in 233 patients with non-massive hemoptysis. All patients had a history of persistent or recurrent hemoptysis despite conservative medical treatment. We assessed the technical and clinical success, recurrence, prognostic factors related to recurrent bleeding, recurrence-free survival rate, additional treatment, and major complications in all the patients.

Results

Technical success was achieved in 224 patients (96.1%), and clinical success was obtained in 219 (94.0%) of the 233 patients. In addition, 64 patients (27.5%) presented hemoptysis recurrence with median time of 197 days after embolization. Tuberculosis sequelae and presence of aberrant bronchial artery or non-bronchial systemic collaterals were significantly related to recurrent bleeding (p < 0.05). The use of Histoacryl-based embolic materials significantly reduced the recurrent bleeding rate (p < 0.05). Patient who had a tuberculosis sequelae showed a significantly lower recurrence-free survival rate (p = 0.013). Presence of aberrant bronchial artery or non-bronchial systemic collaterals showed a statistically significant correlation with recurrence-free survival rate (p = 0.021). No patients had major complications during follow-up.

Conclusions

BAE is a safe and effective treatment to manage non-massive hemoptysis. The procedure may offer a better long-term control of recurrent hemoptysis and quality of life than conservative therapy alone.

The Minimally Invasive Treatment of Visceral Artery Pseudoaneurysms: A Retrospective Observational Single Centre Cohort Study on Glue Embolization

OBJECTIVE

The objective is to report a single centre experience in the embolization of visceral artery pseudoaneurysms with N-butyl-cyanoacrylate-methacryloxy sulfolane (NBCA-MS).

METHODS

A retrospective observational cohort study was conducted on data about all consecutive patients treated for visceral artery pseudoaneurysms in the Interventional Radiology Unit of SS Annunziata Hospital, in Taranto (Italy) between January 2016 and July 2020. Only patients treated with NBCA-MS embolization were included. Clinical and technical outcomes were evaluated during in-hospital stay and at 3-month follow-up by computed angiotomography (CTA).

RESULTS

Among 89 patients undergoing treatment for visceral artery pseudoaneurysm, a total of 58 (65.2%) patients (n = 32, 55.2% men; median age 45.8 years, range: 35-81) treated with NBCA-MS only were enrolled. Pseudoaneurysms were located in the renal artery (n = 18 cases, 31%), in the splenic artery (n = 27, 46.6%), in the intra-parenchymal hepatic artery (n = 3, 5.2%), in the common hepatic artery (n = 4, 6.9%) or in the pancreatic artery (n = 6, 10.3%). N-butyl-cyanoacrylate was diluted 1:1 with Lipiodol ultra-fluid, and mean volume injected was 0.6 ± 0.3 mL (range: 0.2-2.8 mL). Embolization was technically and clinically successful in all patients (n = 58, 100%) with an immediate total thrombosis of the pseudoaneurysm at the completion angiography. No systemic complications were noted in all cases. Five cases (8.6%) of non-target vessel embolization occurred without any clinical complication. No pseudoaneurysm recurrence was detected at the CTA control 1 day postoperatively. In one case (1.7%), a recurrence was detected 4 days after the initial treatment and successfully managed by a repeated NBCA-MS embolization. During the hospital stay, 56 patients recovered well but 2 (3.4%) died from multi-organ failure not related to the embolization. No recurrences were detected at the 3-month postoperative CTA in the remaining patients.

CONCLUSIONS

In properly selected patients affected with visceral artery pseudoaneurysms, NBCA-MS represents a definitive and safe embolization agent.

Preoperative Ultrasound-Guided Percutaneous Embolization of Orbital Lymphaticovenous Malformations Using Onyx

The treatment of orbital lymphaticovenous malformations (OLVMs) has evolved from simple surgical resection to a multimodal approach consisting of sclerosing agents, embolization, and resection depending on the specific components that compose the lesion. Here we present a representative case series of 5 nonconsecutive patients who underwent percutaneous embolization of OLVMs with the Onyx Liquid Embolic System (Medtronic, Dublin, Ireland) before surgical resection between 2019 and 2021. OLVMs are rare, benign, congenital lesions that grow with age and can become symptomatic and disabling. Treatment can be conservative or invasive; depending on the clinical presentation and characteristics of the lesions, treatment modalities can vary. Preoperative percutaneous embolization of OLVMs with the Onyx system is a promising technique, as demonstrated in this case series.

In Vivo Animal Study of a Highly Viscous N-butyl Cyanoacrylate Medical Adhesive for Intravenous Embolization

N-butyl cyanoacrylate (NBCA) is a liquid monomer that undergoes an exothermic polymerization reaction to form a solid upon initiation with hydroxyl anions. Recently, EGpresto, a highly viscous NBCA-based adhesive, has been developed for vascular-occlusion purposes. In this study, we investigated the heat of polymerization of EGpresto and compared the results with those of a low-viscosity NBCA glue. Results show that EGpresto exhibited a lower heat of polymerization (64 ± 7 °C vs. 34 ± 1 °C). This was due to its high viscosity, which resulted in a delayed polymerization time. To investigate the efficacy and safety of EGpresto for intravenous embolization, a 14 d in vivo animal test was conducted using three pigs. Five cc of EGpresto was injected into the epigastric vein of each animal. Complete postoperative vein occlusion was confirmed at 7 and 14 d by ultrasonographic visualization. After the animals were sacrificed, the operated and unoperated veins were exposed, and the injected adhesive was found without migration. During the histology, the injected adhesive was not found in the inner or outer vein walls, and the immune reactions seemed to be the only foreign-body reaction, showing that EGpresto is a non-toxic and safe intravascular embolic agent.

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.

Embolization using warmed glue via the triaxial microballoon occlusion system for various vascular disorders

PURPOSE

We aimed to illustrate the benefits of using warmed glue for viscosity reduction via the triaxial microballoon system for the treatment of various vascular disorders.

METHODS

Seven patients who underwent 10 treatment sessions for hemoptysis, type II endoleak, post-pancreatic surgical bleeding, spontaneous retroperitoneal bleeding, or ovarian tumor bleeding were evaluated based on technical and clinical outcomes. In the procedure, the triaxial system, consisting of a 4.5-Fr guiding catheter, a 2.8-Fr microballoon catheter, and a 1.9-Fr no-taper microcatheter, was advanced into the target lesion. Glue (33% n-butyl cyanoacrylate mixed with Lipiodol) warmed to 40°C was injected under balloon occlusion.

RESULTS

The common hepatic, right bronchial, intercostals, internal mammary, costocervical, lateral thoracic, superior thoracic, thoracoacromial, inferior thyroid, iliolumbar, lumbar, internal pudendal arteries, and branch of the inferior mesenteric artery were successfully embolized; 100% technical success and 100% clinical success were obtained after each session.

CONCLUSION

Our modified balloon-occluded glue embolization may lead to better handling with more distal glue penetration capability.

Efficacy of transarterial embolisation in patients with life-threatening spontaneous retroperitoneal haematoma

AIM

To evaluate the technical and clinical success of embolisation in patients with life-threatening spontaneous retroperitoneal haematoma (SRH) and to assess predictors of clinical outcome.

MATERIALS AND METHODS

Thirty patients (mean age: 71.9±9.8 years) with SRH underwent digital subtraction angiography (DSA). All patients received anticoagulant or antiplatelet medication or a combination of both at the time the SRH occurred.

RESULTS

Pre-interventional computed tomography angiography (CTA) revealed active retroperitoneal bleeding in 28 of 30 (93.3%) patients. DSA identified active haemorrhage in 22 of 30 patients (73.3%). Twenty-nine of 30 (96.7%) patients underwent embolisation. n-Butyl-2-cyanoacrylate (NBCA) was used in 15 patients (51.7%), coils were used in 10 patients (34.5%), and both embolic agents were used in four patients (13.8%). The technical success rate was 100%. Pre-interventional haemoglobin levels increased significantly after embolotherapy from 70.9±16.1 g/l to 87±11.3 g/l (p<0.001), whereas partial thromboplastin time decreased from 58±38 to 30±9 seconds (p<0.001) after embolotherapy. The need for transfusion of concentrated red cells decreased from 3±2.2 to 1±1.1 units (p<0.001) after the intervention. Clinical success was achieved in 19 of 29 (65.5%) patients. No major procedure-related complications occurred. Seven patients (24.1%) died within 30 days after the procedure.

CONCLUSION

Embolotherapy in patients with life-threatening SRH leads to a high technical success rate and is a safe therapeutic option. The clinical success rate was acceptable and influenced by pre-interventional coagulation status and by the amount of transfused concentrated red cells.

Percutaneous embolization for a subacute gastric fistula following laparoscopic sleeve gastrectomy: a case report and literature review

Background

The management for subacute or chronic fistula after bariatric surgery is very complicated and with no standard protocol yet. It is also an Achilles’ heel of all bariatric surgery. The aim of this case report is to describe our experience in managing this complication by percutaneous embolization, a less commonly used method.

Case presentation

A 23-year-old woman with a body mass index of 35.7 kg/m² presented with delayed gastric leak 7 days after laparoscopic sleeve gastrectomy (LSG) for weight reduction. Persistent leak was still noted under the status of nil per os, nasogastric decompression, and parenteral nutrition for 1 month; therefore, endoscopic glue injection was performed. The fistula tract did not seal off, and the size of pseudocavity enlarged after gas inflation during endoscopic intervention. Subsequently, we successfully managed this subacute gastric fistula via percutaneous fistula tract embolization (PFTE) with removal of the external drain 2 months after LSG.

Conclusions

PFTE can serve as one of the non-invasive methods to treat subacute gastric fistula after LSG. The usage of fluoroscopy-visible glue for embolization can seal the fistula tract precisely and avoid the negative impact from gas inflation during endoscopic intervention.

Endovascular Internal Trapping by Low-Concentration N-butyl-2-Cyanoacrylate for a Ruptured Giant Common Carotid Artery Pseudoaneurysm

Treating carotid blowout syndrome following rupture of giant pseudoaneurysms is difficult because the destroyed parent artery precludes conventional treatment. We present a patient with a ruptured giant pseudoaneurysm that we occluded using a modified internal trapping technique with low-concentration N-butyl-2-cyanoacrylate (NBCA) and a minimum number of coils. An 80-year-old man with a history of chemoradiation therapy for oropharyngeal cancer presented with several episodes of active bleeding from the subsequent tracheostomy site. Radiological examination revealed a giant right common carotid artery (CCA) pseudoaneurysm. Endovascular internal trapping was performed using both NBCA and coils under proximal flow control. We slowly injected 9 ml of low-concentration NBCA, which subsequently filled the entire pseudoaneurysm. We then injected an additional 2 ml of NBCA into the proximal CCA to achieve complete obliteration. No re-bleeding was observed during the 6-month follow-up. Endovascular internal trapping using low-concentration NBCA was feasible to treat a giant CCA pseudoaneurysm. The injected low-concentration NBCA filled the entire pseudoaneurysm without the risk of catheter entrapment.

Effectiveness of bronchial arterial embolization using N-butyl-2-cyanoacrylate for local control of pulmonary hilar or mediastinal tumors that are refractory to chemotherapy

PURPOSE

To investigate local control and survival after bronchial artery embolization (BAE) using N-butyl-2-cyanoacrylate (NBCA) for pulmonary hilar or mediastinal tumors that are refractory to chemotherapy or chemoradiotherapy.

METHOD

This is a single center retrospective study involving 42 patients treated between 2015 and 2018 for pulmonary hilar or mediastinal tumors (primary tumors in 5 and metastatic ones in 37). Tumor histology was sarcoma in 22 and carcinoma in 20 patients. All patients had shown tumor progression regardless of previous chemotherapy (n = 37) or chemoradiotherapy (n = 5). Thirty-seven patients (88 %) had respiratory symptoms, such as cough, dyspnea, and hemoptysis. BAE was performed using NBCA to shrink tumors for extending life expectancy. Target tumors were followed with computed tomography at 1,3, and 6 months after BAE. Endpoints included the best tumor response within 6 months as well as overall survivals in patients with and without tumor responses.

RESULTS

Best local responses within 6 months were complete response (CR) in 1 patient, partial response (PR) in 16, stable disease (SD) in 24, and progressive disease (PD) in 1; the CR/PR rate was 40 % (17/42). Median follow-up period was 13 months (range:1-43). Overall survival in patients with CR/PR was significantly better than in those with SD/PD (p = 0.006); with 3-year survival rates of 45 % (8/17) and 0% (0/25), respectively.

CONCLUSIONS

BAE using NBCA has potential promise for shrinking hilar and/or mediastinal tumors that are refractory to chemotherapy or chemoradiotherapy, and may also improve overall survival in patients who respond.

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.

In vitro and in vivo evaluation of the safety and efficacy of a novel liquid fiducial marker for image-guided radiotherapy

The true extent of a tumor is difficult to visualize, during radiotherapy, using current modalities. In the present study, the safety and feasibility of a mixture of N-butyl cyanoacrylate and lipiodol (NBCA/Lip) was evaluated in order to investigate the optimal combination for application as a fiducial marker for radiotherapy. Four combinations of NBCA/Lip injection (1:1–0.1, 1:1–0.15, 1:3–0.1 and 1:3–0.15 ml) were injected into the subcutaneous tissue of BALB/c mice. The changes in gross histopathology, body weight, skin score, marker volume, neutrophil and macrophage counts were observed to analyze the effects of the different mixing ratios and injection volumes, in order to identify the best combination. Evaluation according to the International Organization for Standardization criteria was further conducted in order to test the biocompatibility of the mixture, including an acute systematic assay with mice, cytotoxicity with L929 fibroblasts and delayed-type hypersensitivity tests with guinea pigs and an intradermal test with rabbits. The results revealed that at the seventh week, 42 markers (42/48; 87.5%) were still visible using computed tomography (CT) imaging. No serious adverse effects were observed throughout the study period; however, the combination of 1:1–0.1 ml had the lowest body weight and worst skin score. A review of the histopathological reaction to NBCA/Lip revealed a combination of acute inflammation, chronic inflammation, granulation tissue, foreign-body reaction and fibrous capsule formation. The 1:1 NBCA combination ratio resulted in the most intense tissue repair reaction and a slower degradation rate of markers. In general, the combination of 1:3–0.15 ml had a better fusion with local tissue, maintained a stable imaging nodule on CT images for 7 weeks and the final biocompatibility test demonstrated its safety. Overall, the findings of the present study demonstrated NBCA/Lip as a safe and feasible fiducial marker, when using the 1:3–0.15 ml combination.

Is the Cessation of Blood Flow Faster than the Polymerization of an n-Butyl Cyanoacrylate-Lipiodol Mixture? An In Vitro Phantom Study

PURPOSE

To compare the polymerization time of n-butyl cyanoacrylate (NBCA) and lipiodol mixture in a static model and a pulsating flow model simulating embolization procedure of small caliber arteries.

MATERIALS AND METHODS

The polymerization time of NBCA-lipiodol mixture was measured by the morphological changes of a glue droplet in a petri dish. For the flow model, we used a 2-mm-inner-diameter polyvinyl alcohol tube connected to a pulsation pump. Bovine serum was supplied from the pump and circulated into the system at 30 ml/min and 60 bpm. A 0.64-mm-inner-diameter silicon microcatheter was inserted into this system, and then, 0.5 ml of glue was injected into the tube. The flow cessation time was defined as the time it took to stop the serum draining from the end of the tube. Six samples of 100, 66, 50, 40, 33, and 20 vol% NBCA were assessed.

RESULTS

The median polymerization times for each concentration were 0.12, 3.72, 12.30, 27.41, 57.68, and 63.67 s, respectively. The median flow cessation times were 0.28, 0.78, 1.43, 3.75, 4.50, and 9.29 s, respectively. The flow cessation time was significantly shorter than the polymerization time for all samples except for 100 vol% cyanoacrylate (p < 0.05).

CONCLUSION

The flow cessation time of cyanoacrylate glue was significantly shorter than the polymerization time in an in vitro experiment. The injected glue possibly stops the blood flow before the completion of polymerization in the vascular system.

Coil-Protected Technique for Liquid Embolization in Neurovascular Malformations

OBJECTIVE

To evaluate the safety and efficacy of the coil-protected technique for liquid embolization in neurovascular malformations.

MATERIALS AND METHODS

Twenty-two patients who underwent coil-protected liquid embolization for symptomatic cranial (n = 13) and spinal (n = 9) arteriovenous fistula (AVF) or arteriovenous malformations (AVMs) were identified. A total of 36 target feeder vessels were embolized with N-butyl cyanoacrylate and/or Onyx (Medtronic). This technique was used to promote delivery of a sufficient amount of liquid embolic agent into the target shunt or nidus in cases where tortuous feeding arteries preclude a microcatheter wedging techniqu and/or to prevent reflux of the liquid embolic agent in cases with a short safety margin. The procedure was considered technically successful if the target lesion was sufficiently filled with liquid embolic agent without unintentional reflux. Angiographic and clinical outcomes were retrospectively evaluated.

RESULTS

Technical success was achieved for all 36 target feeders. Post-embolization angiographies revealed complete occlusion in 16 patients and near-complete and partial occlusion in three patients each. There were no treatment-related complications. Of the six patients who showed near-complete or partial occlusion, five received additional treatments: two received stereotactic radiosurgery for cerebral AVM, two underwent surgical removal of cerebral AVM, and one underwent additional embolization by direct puncture for a mandibular AVM. Finally, all patients showed complete (n = 19) or near-complete (n = 3) occlusion of the target AVF or AVM on follow-up angiographies. The presenting neurological symptoms improved completely in 15 patients (68.2%) and partially in seven patients (31.8%).

CONCLUSION

The coil-protected technique is a safe and effective method for liquid embolization, especially in patients with various neurovascular shunts or malformations who could not be successfully treated with conventional techniques.

In Vitro Evaluation of the Polymerization Properties of N-Butyl Cyanoacrylate/Iodized Oil Mixtures for Lymphatic Interventions

PURPOSE

To evaluate polymerization of N-butyl cyanoacrylate (NBCA)/iodized oil mixtures for lymphatic interventions in vitro.

MATERIALS AND METHODS

Polymerization times of different NBCA/iodized oil mixtures (ratios of 1:0-1:7) were investigated in a static and dynamic experimental setup (performed in a lymph flow model in a silicone tube). Eight lymphatic samples with different triglyceride (TG) concentrations (low TGs, < 50 mg/dL; medium TGs, approximately 100-400 mg/dL; high TGs, > 700 mg/dL) were investigated. Morphologic changes during NBCA polymerization were monitored and recorded by video. Statistical analysis was performed with intergroup comparisons (Kruskal-Wallis test) and multiple regression analysis.

RESULTS

Static experiments showed increasing polymerization times with increasing concentrations of iodized oil as well as increasing concentrations of TGs. In the low-TG group, polymerization time increased from 14 s at a 1:1 ratio of NBCA to iodized oil to 1,336 s at a 1:7 ratio; times in the medium-TG group increased from 21 s (1:1) to 2,546 s (1:7), and those in the high TG group increased from 168 s (1:1) to 16,530 s (1:7). In dynamic experiments, prolongation of polymerization time was less pronounced. For low- and medium-TG groups, total occlusion of the silicon tube was observed in all cases during the embolization procedure at between 26 seconds (1:1 ratio) and 52 seconds (1:7). In the high-TG group, polymerization took considerably longer (between 43 s [1:1] and 467 s [1:7]) or failed completely.

CONCLUSIONS

Polymerization time of NBCA/iodized oil in lymph seems to be prolonged by increasing iodized oil and TG concentrations.

Preoperative Embolization of Venous Malformations Using n-Butyl Cyanoacrylate

Purpose:

The purpose of this study was to evaluate the safety and efficacy of preoperative percutaneous n-butyl cyanoacrylate (nBCA) embolization of venous malformations in children.

Material and Methods:

Clinical data were retrospectively reviewed in children who underwent embolization using nBCA followed by resection of venous malformations.

Results:

A total of 17 embolizations were performed in 14 patients (9 females, mean age: 5.5 years; median age: 3 years; range 0.1-16 years). The venous malformations involved the lower extremity and the knee joint (n = 7), the trunk (n = 4), head and neck (n = 2), and hand (n = 1). n-Butyl cyanoacrylate was diluted with iodized oil at a ratio of 1:3 to 1:5. The mean and median volume of nBCA per procedure were 2.1 and 2 mL, respectively (range: 0.5-8 mL). There were no complications associated with the procedures. The mean and median time between final embolization and resection were 3.6 and 2 days, respectively. All children underwent successful resection of the symptomatic lesions. The estimated mean and median blood loss were 75 and 50 mL, respectively (range: 5-350 mL). The postprocedure course was uneventful, the days to discharge ranged between 1 and 6 days (mean 3 days).

Conclusion:

Initial results suggest that preoperative percutaneous n-butyl cyanoacrylate embolization of venous malformations is safe and effective in children, with the potential for minimizing blood loss and inpatient stay.

Splenic artery embolization with Ankaferd blood stopper in a sheep model

PURPOSE

Splenic artery embolization is a minimally invasive therapeutic procedure utilized in a number of disorders. Ankaferd blood stopper (ABS) is a novel hemostatic agent with a new mechanism of action independent of clotting factors. We aimed to investigate the safety and efficiency of ABS for splenic artery embolization in a sheep model.

METHODS

Seven adult female sheep were included in the study. Selective celiac angiography was performed using a 5F diagnostic catheter and then a 2.7F hydrophilic coating microcatheter was advanced coaxially to the distal part of the main splenic artery. Under fluoroscopic guidance, 6 mL mixture composed of half-and-half ABS and contrast agent was slowly injected. Fluoroscopy was used to observe the deceleration and stagnation of the flow. Control celiac angiograms were obtained immediately after the embolization. After the procedure, the animals were observed for one day and then sacrificed with intravenous sodium thiopental.

RESULTS

Technical success rate was 100%. None of the animals died or experienced a major systemic adverse event during the procedure. All of the spleens appeared dark on macroscopic examination due to excessive thrombosis. Microscopically, the majority of the splenic sinusoids (90%-95%) were necrotic.

CONCLUSION

In our study, splenic artery embolization by ABS was found to be safe and effective in the short-term. Further studies are needed to better understand the embolizing potential of this novel hemostatic agent.

Polymerization kinetics of a mixture of Lipiodol and Glubran 2 cyanoacrylate glue upon contact with a proteinaceous solution

The Glubran 2 cyanoacrylate glue is a liquid embolic agent used to block blood vessels endovascularly. Typically mixed with an iodized oil (Lipiodol) for visualization under X-ray, it polymerizes when in contact with blood and tissues owing to the presence of ions and proteins. The objective of the study is to determine the influence of plasma proteins in the polymerization reaction. A triggering solution containing bovine serum albumin (BSA) and the main blood ions is used as a model of plasma. The polymerization kinetics of Glubran 2-Lipiodol mixtures is measured upon aspiration in a capillary tube and contact with the proteinaceous solution. Having varied the glue and protein concentrations, we show that glue-Lipiodol mixtures with concentrations larger or equal to 25% polymerize when put in contact with an ionic solution containing at least 4% of BSA. The reaction is decomposed into two phases: a fast zwitterionic polymerization induced by the BSA molecules followed by a slower polymerization phase. The reaction speed and extent of the solidification region mostly depend on the glue concentration. The time for the glue solution to polymerize over a 1mm thickness varies from 5s for pure glue to about 1min for a 50% glue concentration, and 10min for a 25% glue mixture. It is the first time that the kinetics of the two polymerization reactions is quantified for Glubran 2, which will provide the information needed by interventional radiologists to optimize the planning of endovascular glue injection.

Percutaneous Direct Needle Puncture and Transcatheter N-butyl Cyanoacrylate Injection Techniques for the Embolization of Pseudoaneurysms and Aneurysms of Arteries Supplying the Hepato-pancreato-biliary System and Gastrointestinal Tract

Aims:

The aim of this study was to evaluate the safety and clinical efficacy of percutaneous direct needle puncture and transcatheter N-butyl cyanoacrylate (NBCA) injection techniques for the embolization of pseudoaneurysms and aneurysms of arteries supplying the hepato-pancreato-biliary (HPB) system and gastrointestinal (GI) tract.

Subjects and Methods:

A hospital-based cross-sectional retrospective study was conducted, where the study group comprised 11 patients with pseudoaneurysms/aneurysms of arteries supplying the HPB system and GI tract presenting to a tertiary care center from January 2015 to June 2016. Four patients (36.4%) underwent percutaneous direct needle puncture of pseudoaneurysms with NBCA injection, 3 patients (27.3%) underwent transcatheter embolization with NBCA as sole embolic agent, and in 4 patients (36.4%), transcatheter NBCA injection was done along with coil embolization.

Results:

This retrospective study comprised 11 patients (8 males and 3 females) with mean age of 35.8 years ± 1.6 (standard deviation [SD]). The mean volume of NBCA: ethiodized oil (lipiodol) mixture injected by percutaneous direct needle puncture was 0.62 ml ± 0.25 (SD) (range = 0.5–1 ml), and by transcatheter injection, it was 0.62 ml ± 0.37 (SD) (range = 0.3–1.4 ml). Embolization with NBCA was technically and clinically successful in all patients (100%). No recurrence of bleeding or recurrence of pseudoaneurysm/aneurysm was noted in our study.

Conclusions:

Percutaneous direct needle puncture of visceral artery pseudoaneurysms and NBCA glue injection and transcatheter NBCA injection for embolization of visceral artery pseudoaneurysms and aneurysms are cost-effective techniques that can be used when coil embolization is not feasible or has failed.

Polymerization kinetics of n-butyl cyanoacrylate glues used for vascular embolization

Vascular embolization is a minimally invasive treatment used for the management of vascular malformations and tumors. It is carried out under X-ray by navigating a microcatheter into the targeted blood vessel, through which embolic agents are delivered to occlude the vessels. Cyanoacrylate liquid glues have been widely used for vascular embolization owing to their low viscosity, rapid polymerization/solidification rate, good penetration ability and low tissue toxicity. The objective of this study is to quantitatively investigate the physical properties of two n-butyl cyanoacrylate (nBCA) glues (Glubran 2 and Histoacryl) mixed with an iodized oil (Lipiodol) at various concentrations. We show that an homogeneous solution results from the mixing of the glue and Lipiodol, and that the viscosity, density and interfacial tension of the mixture increase with the proportion in Lipiodol. We have designed a new experimental setup to systemically characterize the polymerization kinetics of a glue mixture upon contact with an ionic solution. We observe that the whole polymerization process includes two phases: an interfacial polymerization that takes place at the interface as soon as the two liquids are in contact with a characteristic time scale of the order of the minute; a volumetric polymerization during which a reaction front propagates within the mixture bulk with a characteristic time scale of the order of tens of minutes. The polymerization rate, front propagation speed and volume reduction increase with the glue concentrations. It is the first time that such comprehensive results are obtained on liquid embolic agents.

Managing Complications Following Nephron-Sparing Procedures for Renal Masses

Small renal malignancies are commonly treated with nephron-sparing procedures including partial nephrectomy and percutaneous ablation. Although these procedures offer faster patient recovery and preserve renal function, a variety of complications can occur. Here, we review vascular and nonvascular complications associated with nephron-sparing renal mass treatments and discuss options for minimally invasive image-guided management.

Concomitant origin of the anterior or posterior spinal artery with the feeder of a spinal dural arteriovenous fistula (SDAVF)

Background/objective

The concomitant origin of the anterior spinal artery (ASA) or the posterior spinal artery (PSA) from the feeder of a spinal dural arteriovenous fistula (SDAVF) is rare and the exact incidence is not known. We present our experience with the management of SDAVFs in such cases.

Methods

In 63 patients with SDAVF between 1993 and 2015, the feeder origin of the SDAVF was evaluated to determine whether it was concomitant with the origin of the ASA or PSA. Embolization was attempted when the patient did not want open surgery and an endovascular approach was regarded as safe and possible. The outcome of the procedure was evaluated as complete, partial, or no obliteration. The clinical outcome was evaluated by Aminoff–Logue (ALS) gait and micturition scale scores.

Results

Nine patients (14%) had a concomitant origin of the ASA or PSA with the feeder. There were two cervical, five thoracic, and two lumbar level SDAVFs. A concomitant origin of the feeder was identified with the ASA (n=7) and PSA (n=2). Embolization was performed in four patients and open surgery was performed in five. Embolization resulted in complete obliteration in three patients and partial obliteration in one. Using the ALS gait and micturition scale, the final outcome improved in six while three cases remained in an unchanged condition over 2–148 months.

Conclusions

The concomitant origin of the ASA or PSA with the feeder occurs occasionally. Complete obliteration of the fistula can be achieved either by embolization or open surgery. Embolization can be carefully performed in selected patients who are in a poor condition and do not want to undergo open surgery.

Transcatheter arterial embolization with N-butyl cyanoacrylate for arterial esophageal bleeding in esophageal cancer patients

Background

The aim of this study is to evaluate the clinical efficacy and safety of transcatheter arterial embolization (TAE) with N-butyl cyanoacrylate (NBCA) for the treatment of arterial esophageal bleeding in esophageal cancer patients.

Methods

Between November 2008 and December 2014, five esophageal cancer patients underwent TAE with NBCA for the treatment of arterial esophageal bleeding. We retrospectively evaluated the technical and clinical success, recurrent bleeding, and procedure-related complications.

Results

All of the patients had bleeding from the esophageal artery and were in shock at the beginning of TAE. Four patients had a coagulopathy at the time of TAE; however, the TAE could successfully arrest bleeding in all five patients. After TAE, they immediately recovered from the shock state. Two patients were discharged without event, one patient is currently hospitalized for another complication, and the other two patients died due to multiorgan failure. In addition, no procedure-related complications such as esophageal infarction and recurrence of arterial esophageal bleeding were observed during this study.

Conclusions

TAE with NBCA can arrest bleeding in esophageal cancer patients with active arterial esophageal bleeding, even in those with a pre-existing coagulopathy.

Double Coaxial Microcatheter Technique for Glue Embolization of Renal Arteriovenous Malformations

PURPOSE

To demonstrate the technical benefit of the double coaxial microcatheter technique for embolization of renal arteriovenous malformations (AVMs) with n-butyl cyanoacrylate and iodized oil (glue).

MATERIALS AND METHODS

Six consecutive patients (1 man and 5 women; mean age 61 years; range 44-77 years) with renal AVMs were included. Five patients had hematuria, and one had a risk of heart failure due to a large intrarenal arteriovenous shunt. All patients underwent transarterial embolization using glue and the double coaxial microcatheter technique with outer 2.6F and inner 1.9F microcatheters. After glue injection, the inner microcatheter was retracted, while the outer microcatheter was retained. We assessed the complications and clinical outcomes of this technique.

RESULTS

Technical success was achieved in all patients. In 9 sessions, 34 feeding arteries were embolized with glue using the double coaxial microcatheter technique, 1 was embolized with glue using a single microcatheter, and 2 were embolized with coils. The double coaxial microcatheter technique was useful for selecting small tortuous feeding arteries, preventing glue reflux to the proximal arteries, and approaching multiple feeding arteries without complete retraction of the microcatheters. As a minor complication, glue migrated into the venous system in four patients without any sequelae. In all patients, favorable clinical outcomes, including hematuria cessation in five patients and improvement of the large intrarenal arteriovenous shunt in one patient, were obtained without deterioration of renal function.

CONCLUSION

Glue embolization with the double coaxial microcatheter technique was useful for treating renal AVMs with multiple tortuous feeding arteries.

Endoluminal occlusion devices: technology update

Endoluminal occlusion has been performed since the early beginning of interventional radiology. Over recent decades, major technological advances have improved the techniques used and different devices have been developed for changing conditions. Most of these occlusion devices have been implemented in the vascular territory. Early embolization materials included glass particles, hot contrast, paraffin, fibrin, and tissue fragments such as muscle fibers and blood clots; today, occlusion materials include metallic devices, particles, and liquid materials, which can be indicated for proximal or distal occlusion, high-flow and low-flow situations, and in large-caliber and small-caliber vessels, based on need. Technological progress has led to a decreased size of delivery catheters, and an increase in safety due to release systems that permit the withdrawing and replacement of embolization material. Furthermore, bioactive embolization materials have been developed to increase the efficacy of embolization or the biological effect of medication. Finally, materials have been modified for changing indications. Intravascular stents were initially developed to keep an artery open; however, by adding a covering membrane, these stents can be used to occlude the wall of a vessel or other endoluminal structures. This article gives an overview of the devices most utilized for occlusion of endoluminal structures, as well as their major purpose in the endovascular territory.

Disastrous Portal Vein Embolization Turned into a Successful Intervention

Portal vein embolization (PVE) may be performed before hemihepatectomy to increase the volume of future liver remnant (FLR) and to reduce the risk of postoperative liver insufficiency. We report the case of a 71-year-old patient with hilar cholangiocarcinoma undergoing PVE with access from the right portal vein using a mixture of n-butyl-2-cyanoacrylate and ethiodized oil. During the procedure, nontarget embolization of the left portal vein occurred. An aspiration maneuver of the polymerized plug failed; however, the embolus obstructing portal venous flow in the FLR was successfully relocated into the right portal vein while carefully bypassing the plug with a balloon catheter, inflating the balloon, and pulling the plug into the main right portal vein.

Rat model of hindlimb ischemia induced via embolization with polyvinyl alcohol and N-butyl cyanoacrylate

Objective

To investigate the feasibility of a rat model on hindlimb ischemia induced by embolization from the administration of polyvinyl alcohol (PVA) particles or N-butyl cyanoacrylate (NBCA).

Materials and Methods

Unilateral hindlimb ischemia was induced by embolization with NBCA (n = 4), PVA (n = 4) or surgical excision (n = 4) in a total of 12 Sprague-Dawley rats. On days 0, 7 and 14, the time-of-flight magnetic resonance angiography (TOF-MRA) and enhanced MRI were obtained as scheduled by using a 3T-MR scanner. The clinical ischemic index, volume change and degree of muscle necrosis observed on the enhanced MRI in the ischemic hindlimb were being compared among three groups using the analysis of variance. Vascular patency on TOF-MRA was evaluated and correlated with angiographic findings when using an inter-rater agreement test.

Results

There was a technical success rate of 100% for both the embolization and surgery groups. The clinical ischemic index did not significantly differ. On day 7, the ratios of the muscular infarctions were 0.436, 0.173 and 0 at thigh levels and 0.503, 0.337 and 0 at calf levels for the NBCA, PVA and surgery groups, respectively. In addition, the embolization group presented increased volume and then decreased volume on days 7 and 14, respectively. The surgery group presented a gradual volume decrease. Good correlation was shown between the TOF-MRA and angiographic findings (kappa value of 0.795).

Conclusion

The examined hindlimb ischemia model using embolization with NBCA and PVA particles in rats is a feasible model for further research, and muscle necrosis was evident as compared with the surgical model.