Idiopathic portal hypertension in renal transplant recipients: report of two cases.

We present herein the cases of two patients who developed idiopathic portal hypertension (IPH) following renal transplantation. Both patients had been treated with azathioprine and prednisolone for 6 years and 4 months and for 4 years and 7 months, respectively, and presented with splenomegaly and thrombocytopenia suggesting hypersplenism. Celiac angiography showed a dilated splenic artery and vein in both patients. When the splenic artery was obliterated with a balloon catheter in case 1, the portal venous pressure decreased from 51 cmH2O to 36 cmH2O, and the direction of the superiomesenteric venous blood flow became hepatopetal rather than hepatofugal. These results suggested that the spleen might have played an important role in the development of IPH in these two patients. A splenectomy was therefore performed, immediately following which the portal venous pressure decreased remarkably, and the esophageal varices disappeared during the postoperative follow-up period. Microscopic examination of liver biopsies taken at the operation revealed lymphoplasmacytic infiltration with bile duct hyperplasia but no evidence of periportal fibrosis, and electron microscopy demonstrated very mild perisinusoidal fibrosis. Thus, the histological changes seen in the livers of these patients seemed not to have caused the portal hypertension. In conclusion, although few patients develop IPH after renal transplantation, we should be aware of its possibility and consider splenectomy as the treatment of choice.