BRTO 2026: Complete Gastric Varices Obliteration Protocol

What is balloon-occluded retrograde transvenous obliteration?

Balloon-occluded retrograde transvenous obliteration (BRTO) is an interventional radiology procedure designed to treat gastric varices by accessing the portosystemic shunt that drains them—most commonly the gastrorenal shunt (GRS)—and injecting a sclerosing agent under balloon occlusion.¹ Unlike transjugular intrahepatic portosystemic shunt (TIPS), which decompresses the entire portal system, BRTO selectively obliterates the variceal complex while preserving physiological portal venous flow to the liver.

First described by Kanagawa et al. in 1996, BRTO was developed and refined primarily in Japan and South Korea before gaining recognition in Europe and North America.² The 2024 AASLD Practice Guidance now recommends BRTO alongside TIPS and endoscopic cyanoacrylate injection for secondary prophylaxis of gastric variceal hemorrhage.³

Indications and patient selection

BRTO is indicated for patients with gastrofundal varices (GOV2 or IGV1) who have a demonstrable gastrorenal or gastrocaval shunt on cross-sectional imaging.⁴ The procedure is particularly advantageous in specific clinical scenarios:

• Acute gastric variceal bleeding: Rescue therapy after failed endoscopic control or as primary definitive treatment in centers with expertise
• Secondary prophylaxis: Prevention of rebleeding in patients who have recovered from an index gastric variceal hemorrhage
• High-risk gastric varices: Prophylactic obliteration of large, tortuous varices with high bleeding risk
• Contraindications to TIPS: Severe hepatic encephalopathy, Child-Pugh >13 points, high MELD score, or polycystic liver disease
• Portosystemic shunt syndrome: Refractory hepatic encephalopathy associated with large spontaneous shunts

Relative contraindications

BRTO may be unsuitable when there is no identifiable gastrorenal or gastrocaval shunt, severe renal dysfunction (particularly with ethanolamine oleate use), active uncontrolled infection, uncorrectable coagulopathy, or massive ascites that may worsen after shunt obliteration.⁶ Large esophageal varices also require caution, as portal pressure elevation after BRTO can precipitate esophageal variceal bleeding in up to 33% of patients.⁷

Anatomical considerations and shunt assessment

Successful BRTO requires detailed understanding of the portosystemic collateral anatomy. The gastrorenal shunt (GRS) connects the gastric varices to the left renal vein and is present in approximately 80–90% of patients with gastric varices.⁸ Alternative drainage pathways include the gastrocaval shunt (direct to IVC), inferior phrenic vein, and paravertebral veins.

Imaging assessment

Pre-procedure CT or MR venography should evaluate:

• GRS diameter, tortuosity, and angulation
• Presence of afferent veins (left gastric, short gastric, posterior gastric)
• Efferent collateral veins (inferior phrenic, pericardiophrenic, adrenal, lumbar)
• Portal vein patency and flow direction
• Esophageal variceal size and ascites volume

Identification of all efferent channels is critical, as untreated collaterals permit sclerosant escape and reduce obliteration rates.⁹

BRTO technique and sclerosing agents

BRTO is performed under fluoroscopic guidance, typically via a right femoral or internal jugular venous approach.¹⁰ A 6–9 French vascular sheath is placed, followed by selective catheterization of the left renal vein and GRS using a Cobra or Simmons catheter.

Balloon occlusion and venography

A balloon occlusion catheter (10–30 mm diameter) is advanced into the GRS and inflated to achieve complete occlusion. Confirmatory venography with 5–10 mL of contrast verifies occlusion and maps the variceal filling pattern.¹¹ The balloon is typically inflated for 2–4 hours, or overnight if using low-concentration ethanolamine oleate iopamidol (EOI).

Sclerosing agents

Two primary sclerosants are used:

• 5% Ethanolamine oleate iopamidol (EOI): The traditional agent. Causes endothelial injury and thrombosis. Mixed with iopamidol for radiopacity. Requires prolonged balloon inflation (2–4 hours or overnight) due to slow action.¹² Risk of hemolysis (20–30%) and renal dysfunction (5–10%).
• 3% Sodium tetradecyl sulfate (STS) foam: Creates a stable foam when mixed with air. Faster action allows shorter procedure times. Lower hemolysis risk but similar efficacy.¹³

Modified techniques: PARTO and CARTO

Modified BRTO techniques have emerged to address the procedural burden of prolonged balloon inflation and overnight hospitalization.

Plug-assisted retrograde transvenous obliteration (PARTO)

PARTO deploys a vascular plug (typically Amplatzer Vascular Plug II or IV, sized 15–25% larger than the GRS diameter) within the gastrorenal shunt, followed by retrograde injection of gelatin sponge (Gelfoam) slurry.¹⁵ The plug achieves immediate mechanical occlusion, eliminating the need for prolonged balloon inflation or sclerosing agents. Technical success approaches 100%, with procedure times markedly shorter than conventional BRTO.

Coil-assisted retrograde transvenous obliteration (CARTO)

CARTO uses detachable coils to occlude the GRS, followed by Gelfoam injection.¹⁶ Coils offer size adjustability for tortuous or large shunts where plugs may be technically challenging. Both PARTO and CARTO demonstrate comparable variceal obliteration rates to BRTO with reduced procedure-related complications and shorter hospital stays.

Expected outcomes and survival

BRTO achieves technical success in 90–98% of cases and complete variceal obliteration in 80–90%.¹⁷ A landmark 2015 meta-analysis of 1,016 patients from 24 studies demonstrated technical success of 96.4%, clinical success of 97.3%, and rebleeding rates under 10%.¹⁸

Rebleeding and recurrence

Long-term outcomes are favorable:

• 1-year rebleeding-free survival: 85–90%
• 3-year rebleeding-free survival: 75–85%
• Gastric variceal recurrence: 10–20% at 2–3 years, typically managed with repeat BRTO or TIPS

A 2021 randomized controlled trial comparing BRTO to endoscopic cyanoacrylate injection demonstrated superior rebleeding control with BRTO at 1 and 2 years (77% vs. 96.3% and 65.2% vs. 92.6%, respectively; p = 0.004) with no difference in overall survival.¹⁹

Survival

Post-BRTO survival is primarily determined by underlying liver function rather than the procedure itself. A single-center study with 96-month mean follow-up reported 1-year survival of 82.1%, 5-year survival of 76.6%, and 10-year survival of 68.1%.²⁰ Child-Pugh A/B classification and total bilirubin <3.5 mg/dL were significantly associated with improved survival.

Hepatic encephalopathy and liver function

BRTO preserves portal venous flow, resulting in lower rates of new or worsening hepatic encephalopathy compared to TIPS.²¹ Interestingly, several studies have demonstrated improved serum albumin and INR after BRTO, suggesting potential enhancement of hepatic synthetic function through restoration of portal perfusion.²²

Complications and follow-up

BRTO is generally well tolerated, with major complication rates below 5%.²³ However, specific complications require anticipation and management.

Procedure-related complications

• Hemolysis: Occurs in 20–30% of patients receiving EOI, due to the detergent effect on red blood cells. Monitor haptoglobin, LDH, and hemoglobin.²⁴
• Renal dysfunction: 5–10% with EOI, related to high iopamidol concentration and hemoglobinuria. Prevent with aggressive hydration and octreotide.
• Fever and post-embolization syndrome: Expected in 30–40%; self-limiting over 2–5 days.
• Gastric mucosal ulceration: 5–10%; managed with proton pump inhibitors.
• Portal vein thrombosis: Rare (<2%); may require anticoagulation.

Portal hypertension sequelae

Obliteration of the decompressive GRS increases portal pressure, potentially causing:

• Worsening ascites: 22% of patients; usually managed with diuretics
• New or worsening esophageal varices: Up to 33%; requires surveillance endoscopy and beta-blocker therapy
• Splenic vein thrombosis: Rare; may complicate portal hypertension

BRTO versus TIPS for gastric varices

The choice between BRTO and TIPS depends on patient anatomy, liver function, and institutional expertise.

The 2024 AASLD guidance recommends endoscopic cyanoacrylate as first-line for acute gastric variceal bleeding, with BRTO or TIPS reserved for failures or secondary prophylaxis.²⁶ BRTO is preferred when hepatic encephalopathy, severe ascites, or poor hepatic reserve contraindicate TIPS.

Further reading

1. TIPS Procedure: Transjugular Intrahepatic Portosystemic Shunt Protocol
2. TACE 2026: Complete Clinical Protocol Guide for Hepatocellular Carcinoma
3. Y-90 Radioembolization 2026: Complete TARE Protocol Guide
4. PTBD Procedure: Percutaneous Transhepatic Biliary Drainage Guide
5. Strategic Advancements in Interventional Radiology: Systematic Literature Review

Conclusion

Balloon-occluded retrograde transvenous obliteration has evolved from a specialized Asian technique to an internationally recognized standard for gastric variceal management. The procedure’s unique advantage—selective variceal eradication with preserved portal perfusion—makes it indispensable for patients with poor hepatic reserve, prior hepatic encephalopathy, or anatomical contraindications to TIPS.

The advent of modified techniques (PARTO and CARTO) has streamlined the procedure, reduced hospitalization, and broadened applicability. As evidence accumulates for BRTO in portosystemic shunt syndrome and hepatic encephalopathy, its role within the hepatobiliary interventional armamentarium will continue to expand. Multidisciplinary collaboration between interventional radiology, hepatology, and gastroenterology remains essential for optimal patient selection and outcomes.

References

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