Portal hypertension secondary to myelofibrosis: a study of three cases.

Background: In patients with idiopathic myelofibrosis (IM), portal hypertension (PHT) without thrombosis of the hepatic or splenoportal veins is infrequent.
Objective: To ascertain the mechanisms responsible for the development of PHT in IM and their therapeutic implications.
Patients and Methods: Color Doppler ultrasound with portal flow quantification, hepatic hemodynamic studies, and histological examinations of the liver biopsies were performed in three IM patients with PHT in whom hepatic and splenoportal thrombosis were ruled out.
Results: Two patients showed sinusoidal PHT (increased hepatic venous pressure gradient), normal portal flow, and massive myeloid metaplasia of the liver. Transjugular intrahepatic portosystemic shunt (TIPS) was indicated for variceal bleeding and ascites unresponsive to medical therapy, and resulted in an adequate control of these PHT complications. At the time of TIPS placement, direct portal pressure measurement showed a marked presinusoidal component in the PHT. A third patient died as a consequence of the IM before treatment of PHT could be instituted. This patient showed an extremely increased portal flow and lesser hepatic infiltration.
Conclusions: IM patients with PHT might have a marked presinusoidal component contributing to PHT that is underestimated by hepatic vein catheterization. Treatment of the complications of PHT might not differ from that of patients with cirrhosis.