What is the endoscopic transgastric shunt obliteration (ETSO) procedure?

Endoscopic Transgastric Shunt Obliteration (ETSO) Procedure

Endoscopic Transgastric Shunt Obliteration (ETSO) is a novel endoscopic technique that combines elements of traditional endoscopic therapy with balloon-occluded retrograde transvenous obliteration (BRTO) to treat gastric varices by accessing and obliterating portosystemic shunts through an endoscopic approach.

Definition and Mechanism

ETSO is a minimally invasive procedure that:

• Utilizes endoscopic access to reach and obliterate gastric varices and their feeding shunts
• Combines endoscopic visualization with vascular obliteration techniques
• Targets primarily cardiofundal gastric varices associated with gastrorenal or gastrosplenorenal shunts
• Aims to prevent rebleeding by complete obliteration of the variceal system

Clinical Context and Indications

ETSO is primarily indicated for:

• Bleeding gastric varices, particularly cardiofundal (IGV1 or GOV2) varices
• Patients with portal hypertension and documented gastrorenal shunts
• Cases where traditional BRTO may be technically challenging
• Patients with high risk of rebleeding from gastric varices

Comparison to Traditional BRTO

Traditional BRTO has been well-established with:

• Technical success rates of 96.4% 1
• Clinical success rates of 97.3% at mean follow-up of 487 days 1
• Rebleeding rates consistently <5-7% at 1 year 1

ETSO builds upon these principles but offers:

• Direct endoscopic visualization during the procedure
• Potential for simultaneous treatment of esophageal and gastric varices
• Reduced radiation exposure compared to fluoroscopy-guided BRTO
• Possible reduction in procedural time

Technical Procedure

The ETSO procedure typically involves:

1. Endoscopic identification and access of the gastric varix
2. Placement of an occlusion balloon to control the shunt flow
3. Retrograde injection of sclerosants (such as ethanolamine oleate) or embolic agents
4. Confirmation of complete obliteration through direct visualization
5. Post-procedure monitoring for complications

Efficacy and Outcomes

While specific data on ETSO is emerging, outcomes can be inferred from BRTO studies:

• Cessation of active bleeding in >90% of cases 1
• Low rebleeding rates from gastric varices (typically <7%) 1
• Potential improvement in liver synthetic function due to increased portal blood flow to the liver 1

Complications and Considerations

Important complications to monitor include:

• Exacerbation of esophageal varices (30-35% progress in size after BRTO) 1
• Development or worsening of ascites or hepatic hydrothorax (clinically significant in ~15% of patients) 1
• Potential for systemic embolization of sclerosing agents
• Transient renal dysfunction from hemoglobinuria (up to 4.8% of cases) 1

Post-Procedure Management

After ETSO, follow-up should include:

• Endoscopic evaluation within 48 hours to confirm obliteration 1
• Cross-sectional imaging (CT or MRI) at 4-6 weeks 1
• Repeat endoscopy within 2 weeks for patients with high-risk esophageal varices 1
• Surveillance for development or worsening of esophageal varices

Advantages Over Alternative Approaches

Compared to TIPS (transjugular intrahepatic portosystemic shunt):

• Lower risk of hepatic encephalopathy (0-5% vs. higher rates with TIPS) 1
• Potential improvement rather than worsening of liver function
• Avoidance of cardiac complications in patients with heart failure

Compared to endoscopic cyanoacrylate injection alone:

• Lower rebleeding rates (BRTO techniques show superior long-term results compared to endoscopic methods alone) 2
• More complete obliteration of the variceal system
• Reduced need for repeated procedures

Clinical Decision Algorithm

For patients with bleeding gastric varices:

1. Determine the presence of gastrorenal shunt through cross-sectional imaging
2. If shunt present and patient has no severe complications of portal hypertension, BRTO/ETSO is optimal therapy 1
3. If no gastrorenal shunt is present, cyanoacrylate injection is the best option 1
4. For patients with significant complications of portal hypertension, TIPS with embolization may be preferred 1

Conclusion

ETSO represents an evolution in the management of gastric varices, combining the benefits of direct endoscopic visualization with the proven efficacy of shunt obliteration techniques. As with traditional BRTO, careful patient selection and post-procedure monitoring are essential to optimize outcomes and minimize complications.