Actual behaviour of N-butyl-2-cyanoacrylate (histoacryl) in a blood vessel: a model of the varix

Endoscopic tissue adhesive injection for gastric varices secondary to hepatic cirrhosis: Complications and management strategies

Gastric varices is a common clinical presentation of portal hypertension induced by hepatic cirrhosis, and gastric variceal bleeding is an emergency with high mortality. Endoscopic tissue adhesive injection plays an important role in the primary and secondary prophylaxis of gastric variceal bleeding, and acute bleeding control. However, this is a technique-demanding operation with nonnegligible complications, of which some may be fatal, such as ectopic embolism. Therefore, the prevention and treatment of such complications are of great importance. Herein, we present a review summarizing the complications and treatment strategies of endoscopic tissue adhesive injection for gastric varices secondary to hepatic cirrhosis.

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.

The Efficacy and the Safety of Prophylactic N-Butyl-2-Cyanoacrylate Injection for Gastric Varices Using a Modified Injection Technique

BACKGROUND

Primary prophylactic N-butyl-2-cyanoacrylate (NBC) injection for nonbleeding gastric varices (GVs) remains controversial. In addition, there is still no consensus concerning the technique, its safety, and long-term results.

AIM

To analyze the safety and the efficacy of NBC for primary prophylaxis of GVs using a modified injection technique.

METHODS

Between February 2004 and June 2014, a total of 72 patients with GVs with a high risk of bleeding, who received undiluted NBC injection using a modified "sandwich" method for primary prophylaxis in General Hospital of Chengdu Military Command, were enrolled in this retrospective study. All patients were followed up at 1 to 2 weeks, 3 months, 6 months, and thereafter every 6 months or whenever required, using endoscope detection. The rate of obliteration, bleeding, recurrence, and complications was evaluated.

RESULTS

According to the standard Sarin classification, 28 patients were IGV1 and 44 patients were GEV2. Hepatitis B virus infection was the major cause of portal hypertension. The mean number of sessions were 1.4 (1 to 3) and the mean volume of NBC per session was 3.5 mL (1 to 6 mL). One injection per session was used in 41 patients (56.9%) and 2 or more injections were used in the remaining 31 patients (43.1%). During the follow-up (27 mo; range, 12 to 67 mo), complete obliteration of GVs was achieved in 93.1% of the patients (67/72). One session of NBC injection was enough to obliterate GVs in 49 patients (68.1%), and 2 or more sessions were needed in 23 patients (31.9%). In addition, the bleeding and the recurrence rate were 11.1% (8/72) and 15.3% (11/72), respectively, during the follow-up. The cumulative bleeding-free rate at 1, 3, and 5 years was 95.8%, 91.7%, and 88.9%, respectively. Worsening of esophageal varices was observed in 13 patients (9 in GEV2 and 4 in IGV1). No serious complications, such as distal embolism, were observed in all patients.

CONCLUSIONS

Prophylactic endoscopic NBC injection using a modified injection technique may be a safe and effective treatment for gastric fundal varices with a high risk of bleeding.

Endoscopic cyanoacrylate injection with or without lauromacrogol for gastric varices: A randomized pilot study

BACKGROUND AND AIM

Current guidelines recommend injection of cyanoacrylate as first-line therapy to prevent gastric variceal rebleeding. The method still poses a risk of ectopic embolism, which possibly correlates with the volume of cyanoacrylate used. In this trial, we evaluated the short-term efficacy and safety of tissue adhesive injection combined with lauromacrogol for treating gastric varices.

METHODS

Patients admitted to our hospital for variceal hemorrhage were enrolled and blindly randomized into two treatment groups: lauromacrogol group (lauromacrogol-cyanoacrylate-lauromacrogol) and lipiodol group (lipiodol-cyanoacrylate-lipiodol). Patient follow-up was 6 months. Primary outcome was rebleeds, and secondary outcomes were mortality, gastric varices eradication, and treatment-related adverse events.

RESULTS

Between March 6, 2013 and October 16, 2013, 96 patients met the criteria. Two cases were lost to follow-up, and all treated cases were successful. No procedural-related adverse events were observed in either group. Cyanoacrylate volumes used in the lauromacrogol group were significantly less than those of the lipiodol group (0.9 ± 0.5 vs 2.0 ± 1.2 mL, P = 0.000). Eleven patients developed upper gastrointestinal rebleeding, which did not show significant difference between groups. On multivaritate analysis, portal venous thrombosis and fever were potential risk factors of rebleeding. Treatment failure, complications, gastric varices obturation, and survival did not differ between the two groups.

CONCLUSION

Tissue adhesives combined with lauromacrogol is a safe therapeutic option for gastric varices, with comparably less cyanoacrylate volume used. Because of the small number of study patients, it cannot be proven to have better efficacy than without lauromacrogol. Multicenter studies with larger patient groups are necessary.

Endoscopic tissue adhesive injection for treatment of gastric variceal bleeding

Endoscopy is an important means for the prevention and treatment of gastric variceal bleeding. With definite curative effects and mild side effects, endoscopic tissue adhesive injection has become a preferred first-line treatment for gastric variceal hemorrhage and is now widely used in clinical practice. However, it is still controversial regarding surgical technique, long-term efficacy, risk of complications, and the effect of secondary prevention of gastric variceal bleeding. This article makes a summary of the above points of dispute.

Management of gastric varices: a French national survey

BACKGROUND AND AIMS

Bleeding from gastric varices is more severe than that from esophageal varices, but its management remains debated. We aimed to determine how French hepatogastroenterologists manage cirrhotic patients with gastric varices.

METHODS

Hepatogastroenterologists (n=1163) working in general or university hospitals received a self-administered questionnaire.

RESULTS

Overall, 155 hepatogastroenterologists (13.3%) from 112 centers (33.3%; 39/40 university hospitals, 73/296 general hospitals) answered. Primary prophylaxis was used by 98.1% of hepatogastroenterologists as follows: β-blockers 96.1% (93.8 vs. 97.0%; university vs. general hospitals respectively; P=0.57), glue obliteration 16.9% (17.2 vs. 16.3%; P=0.88), and transjugular intrahepatic portosystemic shunt (TIPS) 8.0% (12.7 vs. 4.6%; P=0.12). To manage bleeding, university hospitals had greater local access to glue obliteration (95.4 vs. 68.2%; P<0.001) and TIPS (78.5 vs. 3.5%; P<0.001). Early TIPS was proposed by 53.6% (72.1 vs. 39.2%; P<0.001). Glue obliteration was performed under general anesthesia (86.1%) using Glubran (43.1%) or Histoacryl (52.9%), and lipiodol (78.8%) with varying degrees of dilution (1 : 10 to 3 : 4). The injected volume per varix varied widely (1-20 ml). Glue obliteration, band ligation, or both were used by, respectively, 64.2, 18.2, and 17.5% of practitioners. Almost all hepatogastroenterologists (98%) performed secondary prophylaxis: β-blockers 74.7% (75.0 vs. 74.4%, university vs. general hospitals; P=0.93), glue obliteration 66.0% (76.9 vs. 57.6%; P=0.013), and TIPS 30.0% (39.1 vs. 23.3%; P=0.037).

CONCLUSION

The management of gastric varices in France is heterogeneous across centers. University hospitals have better access to techniques such as glue obliteration and TIPS. As bleeding from gastric varices has a poor outcome, guidelines should be established to standardize clinical practices and design further studies.

Echo-endoscopic analysis of variceal hemodynamics in patient with isolated gastric varices

Background:

It is considered that gastric varices (GVs) which have the large form in endoscopic view should be treated because they are regarded as having high blood flow volume and the risky varices of hemorrhage. However, there is no data of the correlation among the endoscopic view, diameter of GV, and blood flow volume in GV. The aim of this study was to investigate whether GV diameter correlates to blood flow volume or not. In addition, the correlation between the endoscopic findings of GVs, patient status, and blood flow volume was assessed.

Materials and Methods:

In this study, 24 patients were enrolled. Variceal form and its location were observed using flexible GI endoscopes. Assessment of variceal form and location was according to Japanese society of portal hypertension. Then, the GV diameter (the maximum short axis), the GV flow velocity, and the GV flow volume were measured by echo-endoscope with curved linear array or with electronic radial array.

Results:

Nineteen of 24 enrolled patients were analyzed. There was strong correlation between the GV diameter and the GV flow volume (rs = 0.85, P < 0.01). No significant difference in the GV diameter and the GV flow volume was found between each location. However, there was no significant difference in the GV diameter between each variceal form. In addition, no significant difference was found among Child–Pugh classifications, and in cases associated with or without hepatocelluer carcinoma.

Conclusions:

Strong correlation was found between GV diameter and flow volume of GV, regardless of the location. However, since there was no significant difference in the GV diameter between each variceal form in endoscopic view, measuring GV diameter is important to understand its hemodynamics for further treatment.

[Mexican consensus on portal hypertension]

The aim of the Mexican Consensus on Portal Hypertension was to develop documented guidelines to facilitate clinical practice when dealing with key events of the patient presenting with portal hypertension and variceal bleeding. The panel of experts was made up of Mexican gastroenterologists, hepatologists, and endoscopists, all distinguished professionals. The document analyzes themes of interest in the following modules: preprimary and primary prophylaxis, acute variceal hemorrhage, and secondary prophylaxis. The management of variceal bleeding has improved considerably in recent years. Current information indicates that the general management of the cirrhotic patient presenting with variceal bleeding should be carried out by a multidisciplinary team, with such an approach playing a major role in the final outcome. The combination of drug and endoscopic therapies is recommended for initial management; vasoactive drugs should be started as soon as variceal bleeding is suspected and maintained for 5 days. After the patient is stabilized, urgent diagnostic endoscopy should be carried out by a qualified endoscopist, who then performs the corresponding endoscopic variceal treatment. Antibiotic prophylaxis should be regarded as an integral part of treatment, started upon hospital admittance and continued for 5 days. If there is treatment failure, rescue therapies should be carried out immediately, taking into account that interventional radiology therapies are very effective in controlling refractory variceal bleeding. These guidelines have been developed for the purpose of achieving greater clinical efficacy and are based on the best evidence of portal hypertension that is presently available.

A randomized trial of endoscopic cyanoacrylate injection for acute gastric variceal bleeding: 0.5 mL versus 1.0 mL

BACKGROUND

Endoscopic injection of N-butyl-2-cyanoacrylate is the preferred method to treat acute gastric variceal bleeding (GVB). However, its rebleeding rate remains high.

OBJECTIVE

To compare an injection containing 0.5 mL of cyanoacrylate (group A) with an injection containing 1.0 mL of cyanoacrylate (group B).

DESIGN

A single-center, randomized, controlled trial.

SETTING

A tertiary referral center.

MAIN OUTCOME MEASUREMENT

Occurrence of rebleeding.

PATIENTS

Patients with acute gastric variceal bleeding.

RESULTS

Forty-four patients in group A and 47 patients in group B were studied; their clinical characteristics were similar. The treatment stopped active bleeding in approximately 90% of cases in both groups. The rebleeding rate was 29.8% (14/47) in group B compared with 38.6% (17/44) in group A (P = .504; 95% CI, -10.592 to 28.280). On multivariate analysis, concomitant hepatocellular carcinoma, infection, and the size of the gastric varices were independent determinants of rebleeding. More patients in group B than in group A had postinjection fever (>37.5 degrees C) (23/47 vs 12/44, P = .059). Treatment failure, complications, 30-day mortality, and survival did not differ between the 2 groups.

CONCLUSIONS

Due to the small number of study patients, a double dose of cyanoacrylate injection for GVB cannot be proven to have better hemostatic efficacy than a single dose. Multicenter studies with larger patient numbers are necessary to determine whether a double dose is in fact more efficacious.

Soft materials to treat central nervous system injuries: evaluation of the suitability of non-mammalian fibrin gels

Polymeric scaffolds formed from synthetic or natural materials have many applications in tissue engineering and medicine, and multiple material properties need to be optimized for specific applications. Recent studies have emphasized the importance of the scaffolds' mechanical properties to support specific cellular responses in addition to considerations of biochemical interactions, material transport, immunogenicity, and other factors that determine biocompatibility. Fibrin gels formed from purified fibrinogen and thrombin, the final two reactants in the blood coagulation cascade, have long been shown to be effective in wound healing and supporting the growth of cells in vitro and in vivo. Fibrin, even without additional growth factors or other components has potential for use in neuronal wound healing in part because of its mechanical compliance that supports the growth of neurons without activation of glial proliferation. This review summarizes issues related to the use of fibrin gels in neuronal cell contexts, with an emphasis on issues of immunogenicity, and considers the potential advantages and disadvantages of fibrin prepared from non-mammalian sources.

[Treatment of extra-esophageal variceal bleeding with cyanoacrylate]

BACKGROUND AND AIMS

Endoscopic obliteration of bleeding extra-esophageal varices using N-butyl-2-cyanoacrylate (Histoacryl) has been validated by several authors. The aim of the present paper is to describe the intravariceal injection technique using cyanoacrylate and to present the own results and complications observed in conjunction with the haemostatic treatment.

PATIENTS AND METHODS

A total of 11 intravariceal injection treatments of N-butil-2-cyanoacrylate were performed in 8 patients (3 males, 5 females, mean age 65.5 years) with extra-esophageal variceal bleeding. In 7 cases the bleeding varices were located in the gastric fundus and in one case the varix was found in the duodenum. Variceal bleeders under subintensive care were treated early electively with 1:1 ratio cyanoacrylate-lipiodol intravariceal injection solutions. The injection needle was inserted trough a standard endoscope.

RESULTS

Early haemostasis was achieved in all patients (11/11) and no early rebleeding occurred. In one case because of repeated episodes of late recurrent bleedings 3 more injection treatments were performed. In another case several hours after the injection a transitional cerebral ischemic attack developed. Injection needle sticking occurred during one treatment. There was no mortality due to acute bleeding while two patients died because of hepatic failure during the follow up period.

CONCLUSIONS

Endoscopic injection of diluted cyanoacrylate and lipiodol appears to be an effective and safe treatment method of the extra-esophageal variceal bleeding. Injection treatment in an early elective fashion can be performed with the standard sclerotherapy equipment.

An improved reproducible canine model of esophagogastric varices

AIM: To improve canine model of esophago-gastric varices.

METHODS: A total of 26 canines were used to establish the models of esophagogastric varices with different methods. In group A, nine models of esophagogastric varices were established with two silk in portal vien.In group B, a side-to-side portocaval shunt was performed in 17 canines, with the inferior vena cava ligated, and the portal vein was gradually constricted by a balloon constrictor in order to increase portal vein pressure. The portal pressure, esophagogastric varices grades, coronary venography, and esophageal pathologic changes were examined in both groups.

RESULTS: The mean portal pressure was significantly higher in group B than that in group A (20.7 ± 2.4 cm H₂O vs 16.3 ± 2.5 cm H₂O, P < 0.05). The esophagogastric varices grades (P = 0.026), numbers (2.7 ± 1.0 vs 4.1 ± 1.2, P < 0.05) and diameters (1.4 ± 0.3 mm vs 2.1 ± 0.8 mm, P < 0.05) of varicose veins were also significant different between group A and B.

CONCLUSION: The portocaval shunt with a balloon constrictor is feasible and reliable for the induction of esophagogastric varices.

An injectable tissue-engineered embolus prevents luminal recanalization after vascular sclerotherapy

BACKGROUND/PURPOSE

Sclerotherapy for vascular malformations is often limited by luminal recanalization. This study examined whether an injectable tissue-engineered construct could prevent this complication in a rabbit model of venous sclerotherapy.

METHODS

Ethanol sclerotherapy of a temporarily occluded jugular vein segment was performed in 46 rabbits, which were then divided into 3 groups. Group I (n = 16) had no further manipulations. In groups II (n = 15) and III (n = 15), 0.5 mL collagen hydrogel was injected intraluminally, respectively, devoid of and seeded with autologous fibroblasts. At 1, 4, and 20 to 24 weeks postoperatively, vein segments were examined for patency and resected for histological evaluation. Statistical analysis was by Fisher's Exact test.

RESULTS

All vein segments were occluded at 1 and 4 weeks in all groups, despite histological evidence of progressive endothelial ingrowth. However, at 20 to 24 weeks, angiography demonstrated restoration of vessel patency in groups I (3/6) and II (3/5), but not in group III (0/6; P = .043), in which histology confirmed an obliterated lumen for all vessels.

CONCLUSION

An injectable, fibroblast-based, engineered construct prevents midterm to long-term recanalization in a leporine model of vascular sclerotherapy. This novel therapeutic approach may prevent recurrence of vascular malformations after sclerotherapy, thus reducing the need for repeated procedures and morbid operative resections.

Enhancement of intravascular sclerotherapy by tissue engineering: short-term results

BACKGROUND/PURPOSE

Treatment of vascular malformations with sclerotherapy is often complicated by reexpansion secondary to endothelial recanalization. This study examined the use of an autologous fibroblast construct to enhance intraluminal scar formation after sclerotherapy.

METHODS

New Zealand rabbits (n = 15) underwent ethanol sclerotherapy of a segment of the facial vein. After intraluminal saline flush, animals were equally divided into 3 groups. In group I, no further manipulations were performed. In groups II and III, collagen hydrogel was injected into the sclerosed vein, respectively, without and seeded with autologous green fluorescent protein-labeled fibroblasts. One week postoperatively, the vein segments were examined for patency and resected for histology.

RESULTS

The sclerosed vein segments remained occluded in all animals. Histological examination of luminal thrombi demonstrated numerous viable fibroblasts in group III, whereas there were none in the control specimens from groups I and II. The presence of the injected autologous green fluorescent protein-labeled fibroblasts within thrombi of group III was confirmed by immunohistochemistry.

CONCLUSIONS

An injectable tissue-engineered construct enhances sclerotherapy of the jugular vein in a leporine model by reliably delivering fibroblasts that populate the resultant thrombus. Further analysis of this novel therapeutic concept as a means to augment permanent scar formation and reduce luminal recanalization is warranted.

In-Vitro Simulation of NBCA Embolization for Arteriovenous Malformation

SUMMARY

Embolization using n-butyl-cyanoacrylate (NBCA) for arteriovenous malformation (AVM) is now a daily practice over the world, but there exists no objective data that can be a basis for discussion or decision-making on the best concentration and injection rate of NBCA mixture. The purpose of this study was to obtain objective data on control and behavior of NBCA mixture with an in vitro simulation system of NBCA embolization for AVM. A nidus model made of a one-ml syringe filled with small beads was connected to a pulsatile flow circuit. A microcatheter was introduced just before the nidus model. Endoluminal pressures proximal and distal to the nidus and flow volume through the nidus were measured. Digital subtraction angiography (DSA) was performed to calculate transit time of the contrast medium (CM) through the nidus. NBCA was injected at various rates with an autoinjector and transit time of NBCA through the nidus was calculated. 27 trials were completed. Transit time of CM through the nidus model is well correlated to flow volume per unit of time through the nidus model. Shorter the transit time, larger was the flow volume per unit of time. The correlation was statistically significant (P < .0001). Though statistical significance was not attained, transit time of NBCA mixture at 50% concentration had a tendency to be correlated to flow volume per unit of time through the nidus, and slower injection of the NBCA mixture led to slower filling of the nidus model. Though this simulation system was artificial and the results should be interpreted carefully, it was shown with this system that transit time of CM through the nidus could be a good index for flow volume per unit of time through the nidus. Also suggested was a possibility to utilize this in vitro system for research and training on NBCA embolization of AVM.

Efficacy and safety of transjugular intrahepatic portosystemic shunt in the treatment of nongastric extraesophageal variceal bleeding

OBJECTIVES

Although esophageal varices are the most common site of variceal bleeding, extraesophageal varices cause up to 30% of variceal bleeding. Unlike esophageal variceal bleeding, the experience in management of extraesophageal variceal bleeding, especially nongastric extraesophageal variceal bleeding is limited, and there are no established guidelines for treatment of nongastric extraesophageal variceal bleeding. This study aims to provide experience in treatment of nongastric extraesophageal variceal bleeding with transjugular intrahepatic portosystemic shunt in a tertiary medical center.

METHODS

We retrospectively reviewed all cases, admitted or transferred to Emory University Hospital, with extraesophageal variceal bleeding who had transjugular intrahepatic portosystemic shunt as the final resolution to control bleeding over a period of 4 years, from January 1999 to January 2003. We also compared the outcomes after transjugular intrahepatic portosystemic shunt for bleeding from gastric varices and nongastric extraesophageal varices.

RESULTS

Forty-one patients (33 gastric varices and 8 nongastric extraesophageal varices) with extraesophageal variceal bleeding who had transjugular intrahepatic portosystemic shunt performed were identified in this study period. Bleeding was controlled immediately in 90% (37/41) of those patients. The mortality was 7% (3/41). The rebleeding rate was 10% (4/41). Encephalopathy occurred in 24% (10/41) of the patients. Patients with gastric varices bleeding appeared to have more advanced liver disease than patients with nongastric extraesophageal varices bleeding. The outcomes after transjugular intrahepatic portosystemic shunt for bleeding from gastric varices and nongastric extraesophageal varices were similar.

CONCLUSIONS

Transjugular intrahepatic portosystemic shunt is an effective and safe treatment of extraesophageal variceal bleeding, including bleeding from gastric varices and nongastric extraesophageal varices.

Interventional endoscopy

PURPOSE OF REVIEW

This review provides an updated summary of gastric interventional endoscopy. Relevant original articles and topic reviews are highlighted in the areas of infection control, light sedation, hemostasis, endoscopic mucosal resection, and endoscopic placement of enteric devices.

RECENT FINDINGS

Several key findings are worth noting: the increased use of propofol by nonanesthesiologists for deep sedation with minimal adverse side effects, the adaptation of tissue adhesive agents for the treatment of bleeding gastric varices, the successful treatment of early gastric cancer by endoscopic mucosal resection, and the development of direct percutaneous endoscopic jejunostomy tubes for patients at high risk of aspiration.

SUMMARY

These recent developments in the field of interventional endoscopy have already made a great impact on clinical care. More advanced procedures can be performed safely while the patient is under deep sedation. Yet, these developments have not slowed down the need for improvement in interventional endoscopy. Researchers continue to look for smaller instruments, better optics, and more advanced accessories. This constant state of flux marks the field of interventional endoscopy and ensures its progress.

Transluminal Occlusion of a Pseudoaneurysm Arising from a Thoracic Aortic Graft Patch Using Catheter Delivery of Thrombin

A 39-year-old man with Marfan syndrome underwent replacement of the aortic valve, root, and ascending aorta for acute type A dissection. Subsequently, he underwent infrarenal aortic replacement for aortic rupture and then graft repair of a thoracoabdominal aneurysm with patch-bearing intercostals. After the third procedure, massive intraperitoneal hemorrhage required three subsequent laparotomies. CT scan showed two thoracic aortic pseudoaneurysms at the patch-graft junction that were sequentially embolized with transcatheter delivery of thrombin.