What is the role of cyanoacrylate (tissue adhesive) in Esophagogastroduodenoscopy (EGD) procedures?

Role of Cyanoacrylate (Tissue Adhesive) in EGD Procedures

Cyanoacrylate glue injection is the recommended first-line endoscopic treatment for bleeding gastric varices, particularly for cardiofundal varices (GOV2 or IGV1), due to its superior efficacy in preventing rebleeding compared to other endoscopic methods. 1

Types of Gastric Varices and Treatment Approaches

Gastric varices are classified based on their location:

• GOV1: Gastroesophageal varices extending along the lesser curvature
• GOV2: Gastroesophageal varices extending into the fundus
• IGV1: Isolated gastric varices in the fundus
• IGV2: Isolated gastric varices elsewhere in the stomach (rare)

Treatment Algorithm Based on Variceal Type:

1. For GOV1 varices:

   • Either endoscopic variceal ligation (EVL) if technically feasible OR
   • Cyanoacrylate glue injection if available 1
   • Post-recovery: Combination of non-selective beta-blockers (NSBBs) and endoscopic therapy 1

2. For Cardiofundal varices (GOV2 or IGV1):

   • First choice: TIPS (Transjugular Intrahepatic Portosystemic Shunt) 1
   • Alternative when TIPS not feasible: Cyanoacrylate glue injection 1
   • Post-recovery: TIPS or BRTO (Balloon-occluded Retrograde Transvenous Obliteration) 1

3. For Ectopic varices:

   • Multidisciplinary approach with options including cyanoacrylate injection, endosonographic coil placement, TIPS, or BRTO 1

Technical Aspects of Cyanoacrylate Injection

Formulation:

• N-butyl-2-cyanoacrylate: Most commonly used in randomized trials 1
• 2-octyl cyanoacrylate: Alternative with longer polymerization time 1
• 4-carbon (butyl) preparations polymerize faster than 8-carbon (octyl) preparations, reducing embolization risk 1

Important Technical Considerations:

• Currently, no cyanoacrylate formulation is FDA-approved for use as a long-term implant in vascularized human tissue in the US 1
• Plant-based oils (like lipiodol) are not recommended as they may increase distal embolization risk 1
• Injection should be performed immediately after needle insertion to avoid exacerbating bleeding 1

Efficacy and Safety

Efficacy:

• Primary hemostasis rate: 96.2-100% 2, 3
• Eradication rate: 70.2-94% 2, 3

Complications:

• Embolization: Most feared complication but clinically significant events are rare (0.7% in largest series) 1
• Pulmonary embolism: Can be severe but rare 4
• Immediate puncture site bleeding: Can be predicted by catheter pull sign and red catheter sign 5
• Rebleeding: Early rebleeding 3.5-6.2%, late rebleeding 8.1-19.5% 2, 3
• Other potential complications: needle impaction, portal vein thrombosis, infection 1

Important Caveats and Recommendations

1. Specialized training required: ECI should only be performed by endoscopists with specific training 1

2. Availability of support: Experienced interventional radiologists should be available in case of complications 1

3. Emerging techniques: Endoscopic ultrasound (EUS)-guided procedures may improve precision and safety but require further evaluation 1

4. Follow-up surveillance: Despite high initial success rates, recurrence of varices after complete obliteration is not infrequent (44% in one study), necessitating continued surveillance 2

5. Regional considerations: Cyanoacrylate injection is not approved for treatment of gastric varices in the United States but is widely used in practice 1

6. Glue extrusion: The glue cast is typically extruded into the lumen within one month in most patients (86.1%) 3

In conclusion, cyanoacrylate tissue adhesive plays a critical role in EGD procedures for the management of bleeding gastric varices, with evidence supporting its superiority over other endoscopic methods for preventing rebleeding, particularly in cardiofundal varices where band ligation is technically challenging.