Angiographic, Hemodynamic, and Histologic Evaluation of Portal Hypertension and Periportal Fibrosis Induced in the Dog by Retrograde Biliary Injections of Sesame Oil

Periportal fibrosis and portal hypertension were induced by periodic retrograde biliary injections of sesame oil for two to three months in 12 cholecystectomized dogs equipped with Thomas cannulas. Stable portal hypertension between 18 and 24 cm of water occurred in four of 12 dogs (baseline: 10.4 +/- 0.5 cm of water); the remaining eight dogs required continuous biliary oil injections to maintain the portal pressure in that range. Portosystemic venous collaterals were first seen three weeks after the initial biliary oil injection and were extensively developed after two months. Hepatopetal portal blood flow decreased 61 +/- 5% during the first six months, with the greatest decrease of 32 +/- 4% occurring in the first month. Hepatic arterial flow did not change in the first month and then began to rise slowly to peak at nine months at 170 +/- 32% of its baseline value. The greatest increase in hepatic arterial flow was found between the sixth and ninth month when the portal flow no longer changed significantly. Hepatic fibrosis originating from the portal triads and around extravasated oil droplets appeared to progress slowly during the entire observation period. Animals with advanced hepatic fibrosis remained in satisfactory general health with liver enzymes usually remaining in the high normal to low pathologic range, allowing extensive follow-up examinations at regular intervals.