|Discussion: Hypertension develops when hepatopedal flow (toward the liver) is impeded by thrombus or tumor invasion. The blood becomes obstructed as it passes through the liver to the hepatic veins and is diverted to collateral pathways in the upper abdomen. The most common mechanism for increased resistance to flow occurs in patients with cirrhosis. This disease process produces areas of micro and macro nodular regeneration, atrophy, and fatty infiltration, which makes it difficult for the blood to perfuse.|
Collateral circulation develops when the normal venous channels become obstructed. This diverted blood flow causes embryologic channels to reopen; blood flows hepatofugally (away from the liver) and is diverted into collateral vessels. Collateral channels may be into the gastric veins (coronary veins), esophageal veins, recanalized umbilical vein, or splenorenal, gastrorenal, retroperitoneal, hemorrhoidal, or intestinal veins.