Portal angiographic and manometric studies were prospectively carried out in 9 cirrhotic patients with spontaneous chronic portal-systemic encephalopathy. Hepatic encephalopathy presented as coma in 8 patients, and was the first manifestation of chronic liver disease in 6 cases. Hemodynamic studies showed a) a large single spontaneous portacaval anastomosis (gastrorenal, splenorenal, gradient (mean +/- SD = 16.3 +/- 5.4 mm Hg); c) a wedge hepatic venous pressure higher than portal pressure in 8 cases (difference: 1-11 mm Hg).