Endoscopic, Portographic, and Hemodynamic Evaluation of Prolonged Propranolol Administration in Pigs with Experimental Portal Hypertension and Esophageal Varices

Abstract

The effect of long-term propranolol administration on esophageal varices, porto-collateral shunting, portal pressure, hepatosplanchnic hemodynamics, and liver function was studied in a pig model with experimentally induced prehepatic portal hypertension and esophageal varices. Five pigs were treated with 160 mg propranolol daily from week 5 to week 24 after portal-vein banding, and five pigs served as non-treated controls. Administration of propranolol caused an initial, significant reduction (20%) of portal venous pressure, followed by a gradual increase to levels not different from control pressures. In contrast, a marked reduction of the caliber of the coronary vein and size of the esophageal varices was noticed. Twenty weeks of propranolol treatment did not change liver blood flow or liver function. We conclude that the size of the varices rather than portal venous pressure depicts the effect of propranolol treatment and suggest that the beneficial effect of propranolol on variceal bleeding can be explained by a reduction in the wall tension of the varices, initiated and maintained by a diminution of splanchnic blood flow.

Key Words:

• Esophageal varices
• liver blood flow
• liver function
• pigs
• portal angi-ography
• portal hypertension
• portal venous pressure
• propranolol