Study of portal vein thrombosis in patients with idiopathic portal hypertension in Japan.

: Background/Aims: The aim of this study was to elucidate the incidence and clinical manifestations of portal vein thrombosis (PVT) in patients with idiopathic portal hypertension (IPH) in Japan during long-term follow-up. Patients and Methods: Twenty-two patients with IPH were examined for PVT by sonography during a follow-up of 12±6 years. Clinical manifestations and patient outcome related to PVT were studied. Seventy patients with liver cirrhosis were examined by sonography as an incidence control of thrombosis. Results: Nine IPH patients had portal thrombosis (9/22, 41%), a higher incidence than in liver cirrhosis patients (7/70, 10%). Those with thrombosis showed ascites, marked hypersplenism, and low serum albumin. Four patients with thrombosis died. Patients without thrombosis showed less clinical problems after long-term follow-up. Plasma antithrombin III and protein C activity decreased in almost half of the patients. However, there were no differences in these parameters between patients with and without thrombosis. Conclusions: In Japan, IPH patients had a high incidence of portal thrombosis, a significant factor for poor prognosis. Whether the management of PVT contributes to an improvement of a clinical course of IPH or not should be clarified in further study.