Intrahepatic portal vein occlusion. A cause of portal hypertension.

Abstract

Intrahepatic portal vein occlusion has recently been postulated as a primary cause of portal hypertension (1, 10). This was based on the presence of intimal sclerosis or organized thrombi partially obstructing the intrahepatic portal radicles of patients in whom other causes of portal hypertension were excluded. Splenoportography in some of these cases has shown obliteration of the segmental or other large branches of the intrahepatic portal vein. Although occasionally similar splenoportograms may be demonstrated in schistosomiasis or cirrhosis, this abnormal intrahepatic vascular pattern was most common in the group of patients with portal hypertension, patent extrahepatic portal vein, and liver biopsies showing normal architecture with varying degrees of portal fibrosis (1). Five patients with portal hypertension of uncertain etiology have recently been studied at the Yale-New Haven Medical Center, and their radiographic and hemodynamic findings form the basis of this report. Particular attention is directed to the radiographic appearance of the larger intrahepatic portal veins. Materials and Methods The clinical features of the 5 patients are presented in Table 1. The portal venous system was visualized by several technics: percutaneous splenoportography with serial filming in 2 patients, single-film percutaneous splenoportography in 1, direct operative portography in 1, and superior mesenteric arteriography with serial filming in 1 patient who had undergone previous splenectomy. Wedged hepatic venous pressure was obtained by the standard method in 3 patients, followed by wedged hepatic venography using 15 ml of contrast material injected by hand with serial filming. Splenic pulp or direct portal pressure was measured in all 5. Discussion In 1965 Mikkelsen et al. (10) reported a series of cases of portal hypertension in which the cause of the obstruction appeared to be intrahepatic portal phlebosclerosis. These authors termed the syndrome “hepatoportal sclerosis.” Their report was significant because it provided a reasonable explanation for the development of portal hypertension in patients without cirrhosis or extrahepatic portal vein occlusion. Previously many such cases were called idiopathic or primary portal hypertension (8, 13, 14). Subsequently, Boyer et al. (1) reported similar findings in 21 patients from India. These patients characteristically present with upper gastrointestinal bleeding or splenomegaly without a history of alcoholism, hepatitis, or other liver disease. Physical signs of cirrhosis are usually absent, and results of liver function tests are either normal or only mildly deranged. Esophageal varices are consistently demonstrated. The gross appearance of the liver is normal, or the capsule may have areas of nodulation. Liver biopsy reveals only portal fibrosis and no evidence of cirrhosis.