Portal Venous System & Collateral Circulation – Quick Reference

Normal Portal Circulation

  • Portal venous blood travels from splanchnic veins to the liver and drains into the inferior vena cava (IVC) via the hepatic veins (direct route).

Collateral Circulation in Portal Hypertension

  • When the direct portal-to-liver route is obstructed, smaller portal–systemic communications become important.
  • Collateral pathways include the lower esophagus, paraumbilical region, splenorenal/gastrorenal routes, retroperitoneal, hemorrhoidal, and intestinal veins.

Major Sites of Portosystemic Collaterals

  • Gastroesophageal junction: between coronary/short gastric veins (portal tributaries) and systemic esophageal veins; risk of life-threatening hemorrhage if ruptured.
  • Paraumbilical veins: run in the falciform ligament; connect the left portal vein to systemic epigastric veins near the umbilicus.
  • Splenorenal and gastrorenal veins.
  • Intestinal veins.
  • Hemorrhoidal veins.
  • Recanalized umbilical vein.
  • Retroperitoneal veins.

Portal Hypertension – Clinical & Sonographic Findings

  • Clinical findings: ↑ liver enzymes, gastrointestinal bleeding, jaundice, hematemesis.
  • Sonographic findings: collateral circulation with reversal of flow, ascites, hepatosplenomegaly.
  • Differential considerations: occlusion of vessels.

Doppler Evaluation (Abdominal Exam)

  • Box 9.6 summarizes Doppler technique for abdominal exams (refer to text for details).
  • Evaluate flow in the extrahepatic portal venous system and the IVC; assess common bile duct size, liver, kidneys, and spleen.
  • Inspect the pelvis, flanks, and lower quadrants for free fluid.

Color Doppler Evaluation of Collateral Circulation

  • Normal: portal venous blood traverses the liver and drains to the IVC via hepatic veins (direct route).
  • When the direct route is blocked, collateral channels form and become the dominant drainage.
  • Esophageal collaterals: lower esophagus communicates with esophageal veins draining the middle third into the azygos system.
  • Paraumbilical veins: connect left portal vein to systemic epigastric veins near the umbilicus.
  • Other collaterals: gastric/coronary veins, splenorenal, gastrorenal, retroperitoneal, hemorrhoidal, and intestinal veins.