Gastrorenal Shunt is the Primary Vein Involved in Gastrocaval Shunt for Gastric Varices
The left gastric vein (coronary vein) is the primary vessel originally involved in gastrocaval shunts for gastric varices, with blood flowing from the mid to distal splenic vein toward the left renal vein via a gastrorenal shunt. 1, 2
Vascular Anatomy of Gastric Varices
Gastric varices develop through specific portosystemic collateral pathways that differ from esophageal varices:
Origin and Flow Pattern: Gastric varices typically originate from the mid to distal splenic vein, with blood flowing toward the left renal vein, inferior vena cava, and other systemic veins 1, 2
Gastrorenal Shunt: The most common and clinically significant pathway for isolated gastric varices is through a gastrorenal shunt, which connects the gastric varices to the left renal vein 1, 2
Anatomical Variations: While the gastrorenal shunt is most common, direct gastrocaval collaterals can also develop in some patients 3
Clinical Significance of Gastrorenal Shunts
Understanding the vascular anatomy of gastric varices is crucial for several reasons:
Treatment Planning: The presence of a gastrorenal shunt is essential for determining the feasibility of balloon-occluded retrograde transvenous obliteration (BRTO) 1
Risk Assessment: Gastric varices with gastrorenal shunts may bleed at lower portal pressures compared to esophageal varices 1
Procedural Complications: In patients with portal vein occlusion, occlusion of the gastrorenal shunt during BRTO can have serious consequences, including splenic engorgement, infarction, and mesenteric venous thrombosis 1
Diagnostic Approach
Cross-sectional imaging is essential for proper evaluation of gastric varices:
Contrast-enhanced CT or MRI: These modalities are highly recommended to identify the inflow and outflow vessels, detect gastrorenal shunts, and determine the feasibility of interventional procedures 1, 2
Endoscopic Ultrasound (EUS): Can provide real-time Doppler interrogation of gastric varices and their feeding vessels 1
Treatment Considerations
The vascular anatomy directly influences treatment options:
BRTO: Most effective when a well-defined gastrorenal shunt is present 1, 3
EUS-guided Therapy: Allows for targeted intervention with coils and/or cyanoacrylate glue, with Doppler confirmation of hemostasis 1
Multidisciplinary Approach: Treatment decisions should be made based on endoscopic appearance, underlying vascular anatomy, and presence of comorbid portal hypertensive complications 1
Pitfalls and Caveats
Anatomical Variations: Not all gastric varices have a gastrorenal shunt; some may have direct gastrocaval collaterals or other pathways 3
Risk of Complications: BRTO in patients with portal vein occlusion can have serious consequences if the gastric varices represent the sole outflow for the splenomesenteric circulation 1
Need for Comprehensive Imaging: Relying solely on endoscopic classification without cross-sectional imaging may lead to suboptimal treatment decisions 1, 2
Understanding the gastrorenal shunt as the primary vascular pathway in gastrocaval shunts for gastric varices is essential for proper diagnosis, risk assessment, and selection of appropriate therapeutic interventions.