A 48-year-old woman from Mumbai with cirrhosis due to hepatitis C presents with hematemesis. Endoscopy confirms esophageal varices secondary to portal hypertension. The radiologist notes on Doppler ultrasound that portal blood flow is reversed (hepatofugal), and there is enlargement of the left gastric vein. Which anatomical relationship explains the development of varices at the gastroesophageal junction?

Explanation

## Portal Hypertension and Portosystemic Collaterals **Key Point:** Portal hypertension leads to the development of portosystemic anastomoses (collateral circulation). The gastroesophageal junction is a critical site where portal and systemic venous systems communicate, making it vulnerable to variceal formation. ### Anatomy of the Left Gastric Vein The **left gastric vein** (also called the coronary vein of the stomach) is a direct tributary of the portal vein. It drains the lesser curvature of the stomach and the lower esophagus. | Vein | Portal Tributary | Drainage Territory | Systemic Anastomosis | |------|------------------|--------------------|-----------------------| | **Left gastric** | Direct to portal vein | Lesser curvature, lower esophagus | Esophageal venous plexus (azygos system) | | Right gastric | Direct to portal vein | Pylorus, antrum | Gastroduodenal venous plexus | | Splenic | Joins SMV to form portal vein | Spleen, greater curvature | Left colic, left renal veins | | Superior mesenteric | Joins splenic to form portal vein | Small intestine, cecum, colon | Systemic veins of abdomen | ### Mechanism of Varices at Gastroesophageal Junction **High-Yield:** When portal pressure rises (>12 mmHg), blood preferentially flows backward (hepatofugal) through the left gastric vein into the esophageal venous plexus, which drains into the **azygos system** (systemic circulation). This creates a direct portosystemic shunt at the gastroesophageal junction. **Clinical Pearl:** The gastroesophageal junction is one of the **five major sites** of portosystemic collateral formation in portal hypertension: 1. **Esophageal varices** — left gastric vein ↔ esophageal plexus (azygos) 2. **Rectal varices** — superior rectal vein ↔ middle/inferior rectal veins 3. **Caput medusae** — paraumbilical veins ↔ superficial epigastric veins 4. **Hemorrhoids** — superior rectal vein ↔ middle/inferior rectal veins 5. **Retroperitoneal collaterals** — colic veins ↔ retroperitoneal veins ### Why Esophageal Varices Bleed The esophageal submucosa is thin and lacks muscular support. The dilated left gastric vein, now engorged with high-pressure portal blood, erodes through the mucosa, causing life-threatening hemorrhage. **Mnemonic: ABCDE of Portosystemic Collaterals** - **A**zygos (esophageal varices) - **B**ackflow in left gastric vein - **C**aput medusae (paraumbilical) - **D**irect portosystemic shunts - **E**xternal hemorrhoids (rectal varices) [cite:Harrison 21e Ch 297]