To clarify the effect of splenomegaly on portal hemodynamics in patients with portal hypertension and esophageal varices, manometric studies were carried out before and after splenectomy during an operation for esophageal varices. The 118 patients evaluated retrospectively had underlying liver cirrhosis (LC) (62), idiopathic portal hypertension (IPH) (42), and extrahepatic portal occlusion (EHO) (14). The weight of the spleen did not differ significantly among the three diagnostic groups: 640 +/- 473.5 g for LC, 780 +/- 414.6 g for IPH, and 683 +/- 457.2 g for EHO. Before splenectomy, portal pressure was significantly elevated in the patients with EHO (410 +/- 85.2 mm H2O) as compared to either the LC or IPH groups (348 +/- 64.1 and 348 +/- 73.5 mm H2O). Following splenectomy the reduction of portal pressure was significantly greater in the EHO group (29 +/- 15.5%) than in either the LC (18 +/- 17.4%) or IPH (19 +/- 17.0%) groups. Each group was subdivided according to severity of splenomegaly: marked (spleen weight > or = 500 g) or slight (spleen weight < 500 g). Patients with LC and marked splenomegaly showed a reduction in liver function parameters as shown by the prolongation of indocyanine retention rate at 15 min as compared to those with slight splenomegaly. Though it is not statistically significant, the average portal pressure tended to be higher among those with marked splenomegaly.(ABSTRACT TRUNCATED AT 250 WORDS)