A 58-year-old man with cirrhosis presents with hematemesis. Upper endoscopy reveals bleeding esophageal varices. Which is the most common site of portosystemic anastomosis responsible for variceal formation in portal hypertension?

Explanation

## Portosystemic Anastomoses in Portal Hypertension **Key Point:** The esophageal venous plexus is the most common and clinically significant site of portosystemic anastomosis, accounting for the majority of variceal hemorrhage in portal hypertension. ### Anatomical Basis The left gastric (coronary) vein drains into the portal system and communicates with the azygos venous system via esophageal tributaries. When portal pressure rises above 12 mmHg (the variceal threshold), these vessels dilate to form esophageal varices. ### Major Portosystemic Anastomoses | Site | Portal Tributary | Systemic Tributary | Clinical Significance | |------|------------------|-------------------|----------------------| | **Esophagus** | Left gastric (coronary) vein | Azygos system | Most common source of life-threatening hemorrhage | | Rectum | Superior rectal vein | Middle/inferior rectal veins | Anorectal varices (less common bleeding) | | Paraumbilical | Paraumbilical veins | Superficial epigastric veins | Caput medusae (cosmetic, rarely bleeds) | | Retroperitoneum | Colic veins | Retroperitoneal veins | Rarely clinically significant | **High-Yield:** Esophageal varices account for ~70% of variceal bleeding in cirrhosis. The left gastric vein is the primary portal tributary involved. **Clinical Pearl:** The variceal pressure gradient (HVPG >12 mmHg) determines risk of rupture. Esophageal varices are the most common cause of death in cirrhotic patients. ### Why Esophagus is Most Common 1. Direct communication between left gastric vein and azygos system via esophageal branches 2. Thin esophageal mucosa offers minimal resistance to rupture 3. High-pressure gradient across the anastomosis 4. Mechanical trauma from food bolus passage increases rupture risk