Effects of a mixture of a low concentration of n-butylcyanoacrylate and ethiodol on tissue reactions and the permanence of arterial occlusion after embolization

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.

Pulmonary Artery Aneurysm in Behcet Disease: Medical, Endovascular or Surgical Intervention

Behçet's disease is a chronic inflammatory condition that predominantly affects the body's blood vessels, exhibiting various clinical manifestations and complications. The exact cause remains unclear, but genetic predisposition, immune responses, and vascular activation are believed to contribute to its development. This disease is more prevalent in certain geographic regions and primarily affects young adults, particularly males. Pulmonary aneurysm, a complication of Behçet's disease, is the leading cause of mortality in Behcet disease. In this review, we summarize the complications of Behcet disease with a focus on pulmonary artery aneurysms. We discussed the medical, endovascular, and surgical management of pulmonary aneurysms in Behcet disease and the indications and outcomes of the different treatment options. Corticosteroids and cyclophosphamide remain the preferred first-line therapy. However, clinical improvement with infliximab or adalimumab, tumor necrosis factor-alpha (TNFα) blocking agents, have been reported after treatment failure with recommended first-line agents. In patients who fail medical therapy or those with life-threatening hemoptysis, endovascular or surgical intervention is the next option. Endovascular interventions include pulmonary artery embolization with coils or acrylic glue and using plugs, occluders, or stents. Endovascular interventions usually have fewer adverse effects than surgery. Although the risk of surgical procedures is high in pulmonary artery aneurysms, it could be a life-saving procedure in patients with life-threatening hemoptysis. Surgical options, including pulmonary artery ligation, aneurysmorrhaphy, segmentectomy, lobectomy, or pneumonectomy are available. However, the results of surgical therapy for Behçet aneurysms are often disappointing.

Liver regeneration after portal vein embolization: comparison between absolute ethanol and N-butyl-cyanoacrylate in an in vivo rat model

PURPOSE

To compare the effects of absolute ethanol (ethanol) and N-butyl-cyanoacrylate (NBCA) on non-embolized liver lobe regeneration in a rat model.

METHODS

Twenty-seven Sprague-Dawley rats underwent portal vein embolization (PVE) using ethanol:lipiodol, 1:1 (ethanol group, n = 11, 40.74%), NBCA:lipiodol, 1:1 (NBCA group, n = 11, 40.74%), or sham treatment (sham group, n = 5, 18.52%). The non-embolized and embolized lobe-to-whole liver weight ratios 14 days after PVE were compared among the groups (n = 5, 18.52%). The expressions of CD68 and Ki-67 and embolized-lobe necrotic area percentages one day after PVE were compared between the ethanol (n = 3, 11.11%) and NBCA (n = 3, 11.11%) groups.

RESULTS

The non-embolized lobe-to-whole liver weight ratio after PVE was significantly higher in the NBCA group (n = 5, 33.33%) than in the ethanol group (n = 5, 33.33%) (84.28% ± 1.53% vs. 76.88% ± 4.12%, P = 0.029). The embolized lobe-to-whole liver weight ratio after PVE was significantly lower in the NBCA group than in the ethanol group (15.72% ± 1.53% vs. 23.12% ± 4.12%, P = 0.029). The proportions of CD68- and Ki-67-positive cells in the non-embolized lobe after PVE were significantly higher in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [60 (48-79) vs. 55 (37-70), P = 0.003; 1 (0-2) vs. 1 (0-2), P = 0.004]. The embolized-lobe necrotic area percentage after PVE was significantly larger in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [29.46 (12.56-83.90%) vs. 16.34 (3.22-32.0%), P < 0.001].

CONCLUSION

PVE with NBCA induced a larger necrotic area in the embolized lobe and promoted greater non-embolized liver lobe regeneration compared with PVE with ethanol.

A feasibility study of percutaneous transhepatic gallbladder filling (PTGBF) in a swine model

Background: Treatments for acute cholecystitis include cholecystectomy and percutaneous drainage. However, some patients are at high risk for surgery, and prolonged drainage can decrease their quality of life. Purpose: To determine the feasibility of percutaneous transhepatic gallbladder filling (PTGBF) with n-butyl-cyanoacrylate (NBCA) in a swine model. Material and methods: After the induction of general anesthesia, percutaneous transhepatic gallbladder puncture to a pig weighing 49 kg using a 20-G-percutaneous transhepatic cholangio drain (PTCD) needle was performed under ultrasound guidance. A 2.1 F-microcatheter was inserted through the outer PTCD needle, then the cystic duct was coil-embolized. The microcatheter was removed, the gallbladder was filled with 25% NBCA-Lipiodol, then the PTCD needle was withdrawn without complications. Blood was sampled and CT images were acquired from the pig immediately after the procedure and on postoperative day 7. The pig was euthanized on postoperative day 7 and the gallbladder was evaluated by microscopy. Results: Vital signs were stable, and the CT images showed that the gallbladder contained NBCA-Lipiodol without complications such as leakage. Hepatobiliary enzymes were not elevated. Histological findings demonstrated loss of most mucosa with partial regeneration, and lymphocytic infiltration. The muscle layer was intact. Conclusion: This technique might offer a feasible alternative to surgery for high-risk patients with acute cholecystitis, but further studies are needed to determine the safety and long-term effects of this procedure.

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.

Preoperative embolization of high-flow peripheral AVMs using plug and push technique with low-density NBCA/Lipiodol

Arteriovenous malformations (AVMs) embolization is considered as a promising option either its single treatment or in combination with surgery, and the use of low-density N-butyl cyanoacrylate (NBCA)/Lipiodol is acceptable mixture agents but its application should be performed by experienced endovascular teams. We describe a successful case preoperative embolization of high-flow AVMs with low-density NBCA/Lipiodol. A 26-year-old male patient was hospitalized with a big pulsatile mass at the right thigh. Doppler ultrasound showed a mass with high systolic, and diastolic velocities coming from the right superficial femoral artery. Angiogram showed a large and high-flow AVM type IV, according to Yakes classification. Low-density NBCA/Lipiodol 12.5% were performed to obstruct all the nidus and feeding arteries. Extirpation surgery was implemented 4 days after the complete embolization procedure.

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.

Angiogenesis in the Septum and Inner Membrane of Refractory Chronic Subdural Hematomas: Consideration of Findings after Middle Meningeal Artery Embolization with Low-concentration n-butyl-2-cyanoacrylate

The middle meningeal artery (MMA) is suggested to play an important role in the recurrence of chronic subdural hematomas (CSDHs). However, the exact mechanisms involved in the recurrence of CSDHs still remain unknown. For recurring CSDHs, MMA embolization is performed using low-concentration n-butyl-2-cyanoacrylate (NBCA) at our hospital. We report new findings and a discussion related to the mechanism of CSDH recurrence based on the imaging findings after MMA embolization, and cases that required craniotomy due to recurrence. The study included eight patients with recurrent CSDH, defined as ipsilateral hematoma re-enlargement within 3 months, and treated with MMA embolization. MMA embolization was performed successfully in all eight patients with no complications. Of the eight patients treated, one patient required craniotomy for the evacuation of CSDHs due to hematoma re-enlargement. NBCA casts were observed in the inner membrane of CSDHs in five of the eight patients by postoperative computed tomography scans. In the case that required craniotomy, the formation of neovasculatures was observed in the inner membrane of the CSDH. Our results suggested that angiogenesis also occurs in the septum and inner membrane through the MMA and the outer membrane of the CSDH. Additionally, these neovascular vessels may be involved in the recurrence of CSDH after MMA embolization. In a future larger study, it is necessary to elucidate in detail the vascular architecture of the CSDH membrane associated with the hematoma re-enlargement, and the effectiveness of MMA embolization that embolized to these peripheral neovascular vessels.

Large animals in neurointerventional research: A systematic review on models, techniques and their application in endovascular procedures for stroke, aneurysms and vascular malformations

Neuroendovascular procedures have led to breakthroughs in the treatment of ischemic stroke, intracranial aneurysms, and intracranial arteriovenous malformations. Due to these substantial successes, there is continuous development of novel and refined therapeutic approaches. Large animal models feature various conceptual advantages in translational research, which makes them appealing for the development of novel endovascular treatments. However, the availability and role of large animal models have not been systematically described so far. Based on comprehensive research in two databases, this systematic review describes current large animal models in neuroendovascular research including their primary use. It may therefore serve as a compact compendium for researchers entering the field or looking for opportunities to refine study concepts. It also describes particular applications for ischemic stroke and aneurysm therapy, as well as for the treatment of arteriovenous malformations. It focuses on most promising study designs and readout parameters, as well as on important pitfalls in endovascular translational research including ways to circumvent them.

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.

A systematic characterization of the factors influencing polymerization and dynamic behavior of n-butyl cyanoacrylate

INTRODUCTION

Brain arteriovenous malformations are abnormal connections between arteries and veins without an intervening capillary bed. Endovascular glue embolization with N-butyl cyanoacrylate (NBCA) is an accepted form of treatment. The reported complication rates vary widely from 2% to 15%, and timing of polymerization appears to play a major role. Additionally, the interaction between NBCA and vessel surface as well as the presence of biological catalysts are poorly understood.

METHODS

Polymerization time was measured for mixtures of Lipiodol/NBCA of 50/50, 70/30, and 60/40. The influence of pH, temperature, and the presence of biological catalysts on polymerization time was investigated. Contact angles were measured on polyvinyl alcohol cryogel (PVA-C), silicone, and endothelial surfaces in a submerged aqueous environment to assess physical surface interactions. High speed video analysis of glue injection through a microcatheter was performed to characterize simulated coaxial flow.

RESULTS

NBCA polymerization rate increased with pH and temperature. A hydrophilic surface such as PVA-C was better than silicone at mimicking the physical properties of endothelium. Live endothelium provided a catalytic surface that at least doubled the rate of polymerization. Blood products further increased the polymerization rate in the following order (slowest to fastest): plasma, platelets, red blood cells (RBCs), and lysed RBCs. These factors could explain the discrepancy between in vitro and in vivo results reported in the current literature. High speed video analysis of NBCA injection showed dripping to jetting transition with significant wall effect which deviated from previous ideal assumptions.

CONCLUSIONS

The determinants of NBCA polymerization rate are multifactorial and dependent mainly on the presence of biological catalysts coupled with flow related wall interaction.

A case of filum terminale arterial venous fistula needed a long arterial access for trans-arterial shunt obliteration

A 78-year-old man was referred to our institution with a predominantly progressive numbness of both legs, and bladder dysfunction with urinary retention. He was diagnosed as the symptomatic arteriovenous fistula of the filum terminale (AVFFT). A trans-arterial embolization (TAE) of the arteriovenous shunt was planned for his symptomatic AVFFT. The long distance between the origin of the radiculo meningeal artery (Th8) and the site of the fistula (S1) resulted in the first TAE having a feeder occlusion. The length of accessible feeder in the first TAE was the longest (about 40 cm) as the past reports of the endovascular therapy. However, complete shunt occlusion was accomplished at a second session two weeks after the initial TAE because a more accessible feeder was developed by the initial feeder occlusion.

Preclinical study on an animal model of a new non-adhesive cyanoacrylate (Purefill®) for arterial embolization

PURPOSE

The goal of this study was to assess the distal dispersion, the adhesion strength to catheter, the vascular toxicity and the ability in excluding embolized vessels using Purefill^® (α-hexil-cyanoacrylate) as embolic material, which is a new high purity cyanoacrylate and compare these results with those obtained with N-butyl-2-cyanoacrylate (Histoacryl^®) and a mixture of N-butyl-2-cyanoacrylate and methacryloxysulfolane.

MATERIAL AND METHODS

In six pigs, the right rete mirabile (RM) and right renal arteries were embolized with α-hexil-cyanoacrylate, and the left rete mirabile and left renal artery were embolized with N-butyl-2-cyanoacrylate and N-butyl-2-cyanoacrylate+Methacryloxysulfolane for comparison. One minute after glue injection through the microcatheter, displacements of the kidney and the pharyngeal artery were measured on angiographic images, before exercising any traction and during catheter pulling, when the forces were maximal. Displacement was measured in terms of distance (mm) with respect to renal pedicles and in terms of angle (°) with respect to the rete. After acute embolization (4 pigs) or three-month follow-up (2 pigs), the kidneys and the RM were removed and further analysed using computed tomography and histopathological examination.

RESULTS

Similar short and long-term embolic efficacies were observed with the three glues. The mean displacement distances of renal pedicles were 2.6mm for α-hexil-cyanoacrylate, 22.6mm for N-butyl-2-cyanoacrylate and 19.8mm for N-butyl-2-cyanoacrylate+Methacryloxysulfolane (P=0.021). The mean angles of displacement of the ascending pharyngeal arteries were for 12.2° for α-hexil-cyanoacrylate, 23.5° for N-butyl-2-cyanoacrylate and 30° for N-butyl-2-cyanoacrylate+Methacryloxysulfolane (P=0.070). Histopathologically, findings were similar for the three glues, immediately and 90 days after embolization.

CONCLUSION

α-hexil-cyanoacrylate has occlusive efficacy in the short and long term similar to those of N-butyl-2-cyanoacrylate and N-butyl-2-cyanoacrylate+Methacryloxysulfolane. In addition, histopathological changes are similar with the three glues immediately or 90 days after embolization. Conversely, α-hexil-cyanoacrylate results in a reduced angle and distance of displacement compared to the other two glues, assumably reflecting a limited adhesive strength.

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.

Comparative study of tissue reactivity to n-butyl-2-cyanoacrylate and nylon monofilament thread on pericranium-cutaneous flaps in rats

PURPOSE

To study the repair of pericranium-cutaneous flaps fixed with suture anchored in a skull bone tunnel or N-butyl-2-cyanoacrylate adhesive in Wistar rats with emphasis on the cellular inflammatory response and the production of types I and III collagen.

METHODS

The operated region in the cephalic region of Wistar rats was removed minutes before euthanasia, fixed in formalin, and subjected to histological preparation. Slides were stained with hematoxylin-eosin and Picrosirius. Standardized counts of polymorphonuclear and mononuclear cells, fibroblasts, and macrophages were performed, and the percentages of types I and III collagen were determined. Data collection occurred on days 3, 7, 14, 21, and 45 postoperatively. A value of p<0.05 was considered statistically significant.

RESULTS

Quantitative analysis of the data showed more fibroblasts in the surgical adhesive group than in the nylon monofilament thread groups (p=0.0211). Qualitative analysis showed higher reactivity in the adhesive group, with a predominance of polymorphonuclear cells from days 3-45 and macrophages from days 3-7. The amount of type I collagen exceeded 80% in the treated and control groups at the end of the experiment.

CONCLUSIONS

Subperiosteal detachment triggers a cellular inflammatory response that is amplified using soft tissue fixation methods. The adhesive n-butyl-2-cyanoacrylate was more reactive than the nylon monofilament thread anchored in the skull bone tunnel.

Transcatheter arterial embolization of acute arterial bleeding in the upper and lower gastrointestinal tract with N-butyl-2-cyanoacrylate

PURPOSE

To assess the clinical utility and safety of transcatheter arterial embolization with N-butyl-2-cyanoacrylate (NBCA) for urgent control of acute arterial bleeding in the upper and lower gastrointestinal tract.

MATERIALS AND METHODS

Therapeutic NBCA embolization was performed in 37 patients (39 cases; mean age, 67.8 years) with acute upper (n = 16) or lower (n = 23) gastrointestinal tract bleeding after endoscopic management had failed. Transcatheter arterial embolization was performed using 1:1 to 1:5 mixtures of NBCA and iodized oil. The most common etiologies of bleeding were colonic diverticulosis (n = 13), malignancy (n = 11), and benign ulcer (n = 7). Coagulopathy was present in 11 patients, and 23 patients were hemodynamically unstable before NBCA embolization. Histologic examination for bowel ischemia was also performed in five patients who underwent excision of the lesion after NBCA embolization.

RESULTS

The technical success rate was 100%. Recurrent bleeding occurred in two patients. Complete hemostasis was achieved in all 11 patients with coagulopathy. Ulcers induced by transcatheter arterial embolization were noted in 6 of 20 patients who underwent endoscopic examination; the ulcers were successfully treated with conservative measures. Histologic examination revealed that despite inflammatory reactions in and around the vessels, no intestinal necrosis secondary to NBCA embolization was found. Hepatic abscess occurred in two cases, and ischemia of the lower limb occurred in one case; these complications were managed by percutaneous drainage and bypass surgery.

CONCLUSIONS

Transcatheter arterial embolization with NBCA is a good treatment option with a high rate of complete hemostasis and a low recurrent bleeding rate, even in patients with coagulopathy.

Temperature-sensitive poly(N-isopropylacrylamide-co-butyl methylacrylate) nanogel as an embolic agent: distribution, durability of vascular occlusion, and inflammatory reactions in the renal artery of rabbits

BACKGROUND AND PURPOSE

We have developed a new thermosensitive liquid embolic agent, PIB nanogel, that can be solidified at body temperature. We thus further investigated the distribution, durability of vascular occlusion, and inflammatory reactions of PIB in embolization of the renal artery of rabbits.

MATERIALS AND METHODS

The bilateral renal arteries of 9 rabbits were first embolized with PIB at different injection rates. The distribution pattern of PIB was investigated by contact radiography and histology 1 hour after embolization. The right renal arteries of 20 rabbits were then embolized with PIB at the proper injection rate. Angiography and pathologic examination of the kidneys were performed at 1 week and 1, 2, and 3 months after embolization to evaluate the long-term outcomes.

RESULTS

With the injection rate increasing, PIB could reach the more distal branch of the renal artery. The proper injection rate was chosen as 0.10 mL/s due to the homogeneous distribution of PIB from the main renal artery to the precapillary level at this rate. During a 3-month follow-up observation period, no angiographic recanalization was observed. Histologically, we found no disruption of the vessel wall or subintimal bleeding, no extravasation of PIB, and no evidence of neovascularization. Moreover, there was only a mild inflammatory response, manifested by few lymphocytic and monocellular infiltration, without foreign body granuloma formation.

CONCLUSIONS

Embolization of the renal artery with PIB was easy and controllable, which could lead to a homogeneous and persistent occlusion without severe inflammatory changes. PIB might be a suitable material for intravascular embolization.

The use of cyanoacrylate adhesives in the management of congenital vascular malformations

This article outlines the use of liquid acrylic adhesives in the management of congenital vascular malformations. Specifically, the chemical features of cyanoacrylates, including the physical and chemical properties, exovascular use of cyanoacrylates, and the techniques for use of these agents, are discussed.

Arteriovenous fistula of the vertebral artery in a female infant with hypotonia and cephalocorporal disproportion

BACKGROUND

Congenital arteriovenous fistulas are exceptional in childhood and imply a therapeutic challenge.

CASE REPORT

A 9-month-old female infant was studied for cephalocorporal disproportion, hypotonia, progressive muscular atrophy and hyperreflexia. Computed tomography of the brain and electroencephalography were normal. Electromyographic patterns suggested proximal myopathic involvement. A continuous murmur with systolic reinforcement was audible in the neck. Angioresonance detected intracranial aneurysmal dilatations behind the bulbo-medullary junction and cerebral panangiography evidenced a direct vertebrovertebral fistula with extra- and intra-cranial varices and extreme medullary compression. Occlusion of the afferent vessel to the aneurismal sack was successfully achieved with a mixture of Histoacryl and 75% lipiodol via a microcatheter.

CONCLUSION

Clinical signs of an arteriovenous fistula may be atypical. Considerable cephalocorporal disproportion and a bruit in the cervical or retromastoidal regions must suggest its existence. Complete obliteration with endovascular embolization permits somatic and neurological recovery.

Ischemic effects of transcatheter arterial embolization with N-butyl cyanoacrylate-lipiodol on the colon in a Swine model

This study was designed to assess the safety of transcatheter arterial embolization (TAE) with n-butyl cyanoacrylate-lipiodol (NBCA-Lp) for the large bowel and to investigate the vital response to NBCA-Lp in a swine model. In nine swine, nine arteries nourishing the colon were embolized with NBCA-Lp (1 ml of NBCA mixed with 4 ml of lipiodol): sigmoid-rectal branch artery in six swine, right colic branch artery in two, and middle colic branch artery in one. The amount of NBCA-Lp was 0.1-0.4 ml. Sacrifice was conducted 3 days after TAE to identify histological infarction. Classification was conducted retrospectively: group A, vasa recta without NBCA-Lp embolization despite TAE; group B, three or fewer vasa recta with NBCA-Lp embolization; and group C, five or more vasa recta with NBCA-Lp embolization. In one swine in group A, no necrotic focus was observed. In group B, three of four swine experienced no ischemic damage. The remaining one swine experienced necrosis of mucosal and submucosal layers in one-fourth of the circumference. In group C, all four swine with marginal artery and five vasa recta or more embolized experienced total necrosis of mucosa, submucosa, and smooth muscle layers of the whole colonic circumference. Significant difference on the extent of ischemic damage was observed between groups B and C (P < 0.05). Microscopically, NBCA-Lp induced acute vasculitis. Embolization of three or fewer vasa recta with NBCA-Lp induced no ischemic damage or limited necrosis, whereas embolization of five or more vasa recta with NBCA-Lp induced extensive necrosis.

Recanalization of splenic artery aneurysm after transcatheter arterial embolization using N-butyl cyanoacrylate

A 65-year-old woman who had been diagnosed as having microscopic polyangiitis developed sudden abdominal pain and entered a state of shock. Abdominal CT showed massive hemoperitoneum, and emergent angiography revealed a ruptured splenic artery aneurysm. After direct catheterization attempts failed due to tortuous vessels and angiospasm, transcatheter arterial embolization using an n-butyl cyanoacrylate (NBCA)-lipiodol mixture was successfully performed. Fifty days later, the patient developed sudden abdominal pain again. Repeated angiography demonstrated recanalization of the splenic artery and splenic artery aneurysm. This time, the recanalized aneurysm was embolized using metallic coils with the isolation method. Physicians should keep in mind that recanalization can occur after transcatheter arterial embolization using N-butyl cyanoacrylate, which has been used as a permanent embolic agent.

Venous vascular malformations of the craniofacial region: pre-operative embolisation with direct percutaneous puncture and N-butyl cyanoacrylate

Craniofacial venous vascular malformations cause severe cosmetic problems and yet these lesions are not candidates for transcatheter embolisation owing to the lack of arterial feeders. The purpose of this study was to evaluate the effectiveness of pre-operative embolisation of these lesions with N-butyl 2-cyanoacrylate (NBCA) via direct puncture. Between September 2003 and April 2006, 13 patients (7 female; age range, 6-64 years; mean, 16.7 years) were embolised with direct puncture and injection of NBCA. All of the patients were referred from plastic surgery with an operational plan. Angiography performed in all patients showed no or little arterial staining. NBCA diluted with iodized oil at a ratio of 1:6 (18%) was injected via a percutaneously placed 21 gauge needle. Complete embolisation was achieved in 8 patients and partial embolisation in the remaining 5. A total of 18 sessions of embolisation were performed on 13 patients. Nine patients underwent only one embolisation session, three patients underwent two sessions and only one patient underwent three sessions. The mean volume of NBCA used per session was 5.8 ml, ranging from 1-12 ml. All patients underwent a successful surgical resection to improve cosmetic disfigurement within 10-15 days after the embolisation procedure. Mean follow-up time was 22 months. One patient experienced skin necrosis on her nose after embolisation. No other complications related to the procedure were observed. In conclusion, pre-operative NBCA embolisation with direct puncture is a safe and easy procedure. It can increase the success of the surgical treatment of these lesions.

Coating the wall of an injured intracranial carotid artery during tumor removal with n-butyl-2-cyanoacrylate: technical case report

OBJECTIVE

Carotid artery injury close to the clinoid process is difficult to repair, and is even more so when the vessel is firmly attached to a calcified tumor. We treated a patient with an intraoperative carotid lesion by coating the vessel wall with n-butyl-2-cyanoacrylate (NBCA).

CLINICAL PRESENTATION

A 7-year-old boy was referred to our clinic with a 3-month history of somnolence, apathy, and headache. Neurological examination revealed bitemporal hemianopsia. The cranial magnetic resonance imaging and computed tomographic scans showed a sellar and suprasellar calcified mass with heterogeneous contrast enhancement, a cyst component in the upper part of the tumor displaced upward and back from the mesencephalic and diencephalic structures.

INTERVENTION

The patient underwent a pterional craniotomy. Using a microsurgical technique, the suprasellar part of the craniopharyngioma was removed. In an attempt to dissect the calcified mass from the carotid artery on the right side, the vessel was unintentionally injured, followed by severe bleeding. Temporary occlusion and suturing of the vessel was impossible because of the overlying hard mass. To avoid a permanent occlusion, we decided to coat the injured artery wall with 100% NBCA. For this, 0.5 ml of NBCA was distributed on the surface of the injured segment and surrounding subarachnoid space by injection through a needle. An excellent hemostasis could be obtained immediately after coating. The patient woke up with no new neurological deficits. A digital cerebral angiogram obtained a few days after the procedure did not show vasospasm, stenosis, or pseudoaneurysm in the supraclinoidal segment of the carotid artery. A magnetic resonance angiogram obtained 3 years later showed a normal shape of the internal carotid artery and a stable residual tumor without inflammatory signs. The child is now attending school and is under hormonal therapy.

CONCLUSION

For hemostatic purposes, the technique of coating an injured arterial wall with NBCA may be useful in cases in which a microsuture is impossible and a permanent artery occlusion is unwanted because of a risk of an ischemic stroke. It could serve as a transitory measure until a microsurgical bypass or the balloon test occlusion tolerance allow the trapping of the affected artery.

Transformation of a ruptured giant pulmonary artery aneurysm into an air cavity after transcatheter embolization in a Behçet's patient

Pulmonary artery aneurysms due to Behçet's disease are mainly seen in young males and very rarely in females. To our knowledge there are only 10 cases reported in the related literature. Emergent transcatheter embolization was performed in a female patient with a known history of Behçet's disease in whom massive hemoptysis developed because of rupture of a giant pulmonary artery aneurysm. At 6-month follow-up, transformation of the aneurysm sac into an air cavity was detected. To our knowledge, such a transformation has never been reported in the literature before. Embolization of the pulmonary artery aneurysm and the mechanism of cavity transformation are reviewed and discussed.

Embolization of a giant pulmonary artery aneurysm from Behcet disease with use of cyanoacrylate and the "bubble technique"

Pulmonary artery aneurysm (PAA) is a common manifestation and leading cause of mortality related to Behcet disease. Endovascular treatment is usually required when medical therapy alone fails to control progression. Successful superselective embolization of a giant PAA with the "bubble technique" was performed with use of a high concentration (75%) of n-butyl-cyanoacrylate in a patient with Behcet disease who had recurrent hemoptysis.

Thermosensitive N-isopropylacrylamide–N–propylacrylamide-vinyl pyrrolidone terpolymers: Synthesis, characterization and preliminary application as embolic agents

In this article, thermosensitive N-isopropylacrylamide (NIPAAm)-N-propylacrylamide (NPAAm)-vinyl pyrrolidone (VP) terpolymers (PNINAVP) were prepared by varying feed ratios with free radical copolymerization method. The composition ratios and molecular weights of PNINAVP were examined by NMR and GPC. The thermo-responsive behaviors of copolymer solutions in the absence and with addition of Iohexol, a radiopaque agent, were investigated by differential scanning calorimetry (DSC) and rheometer. The sol-gel transition of the copolymer solutions occurred reversibly within 1 min in response to temperature. Incorporation of Iohexol increased the transition time and transition temperature of PNINAVP solutions; the rheological properties were also influenced. It was observed that at body temperature, PNINAVP and Iohexol could form an integrated bulky hydrogel presumably due to the hydrogen bonding between them, which was favorable for the clinical follow-up and reducing toxic side effects. In vitro embolic model experiment indicated that 5 wt% 16:16:1H PNINAVP solution containing Iohexol displayed a satisfactory embolization effect. This solution was injected into the rete mirabiles (RM) of six swines through a microcatheter. The angiographical results obtained immediately after the operation showed a complete occlusion of the RM, and no recanalization was observed at postoperative month 1. The histological examination demonstrated no acute inflammatory reaction inside the RM and surrounding tissue. This work could provide a beneficial guidance for designing a new temperature-sensitive polymer-based embolic agent.

Endovascular Treatment of Cerebral Arteriovenous Malformations

The modern management of cerebral arteriovenous malformations (AVMs) is based on three therapeutic modalities: microneurosurgery, endovascular embolization, and stereotactic radiosurgery. Embolization facilitates subsequent radiosurgery by reducing the volume of the nidus, prepares the resection of surgically accessible AVMs, and immediately addresses the risks related to associated intra/extranidal aneurysms and arteriovenous fistulas. We discuss in this article the current state of AVM endovascular therapy.

Percutaneous Treatment of High-Output Chylothorax with Embolization or Needle Disruption Technique

Surgical ligation of the thoracic duct is associated with a high degree of morbidity; therefore, a minimally invasive approach is desirable. Herein, eight percutaneously treated patients are described. In four patients, the thoracic duct was embolized with use of coils and glue. In the other four patients, lymphatic ducts were disrupted by multiple needle punctures. The median chest tube drainage substantially decreased in both patient groups from more than 1,300 mL the day before the procedure to less than 300 mL 2 days after the procedure. The median times to chest tube removal were 7 days in the embolization group and 3.5 days in the needle disruption group.