6 The predominant literature on NRH is in the form of case reports or small case series and there are

only few reports of portal pressure measurements in this condition. In the current issue of the Journal, Bissonnette et al.8 reported hemodynamic measurements, including HVPG, in 21 patients and portal vein pressure gradient (PVPG, portal vein pressure – inferior vena cava pressure) in 12 patients with NRH. The causes of NRH in these patients included oxaliplatin chemotherapy, treatment with purine antagonists, liver transplantation, hematological and rheumatological conditions, and HIV infection. Wnt inhibitor Fifteen out of 21 patients with varices/ascites had HVPG less than 10 mm Hg suggesting a pre-sinusoidal portal hypertension, which was confirmed by a portal vein pressure higher than 12 mm Hg in all 12 patients. Though the majority of patients (15/21) had a pre-sinusoidal component, six patients did have higher HVPG (more

than 10 mm Hg) suggesting sinusoidal portal hypertension.8 These data by Julien et al. thus suggest that both components of portal hypertension (pre-sinusoidal and sinusoidal) occur in patients with NRH. The pre-sinusoidal portal hypertension is related to the well-described vasculopathy (obliterative portal venopathy), while the sinusoidal portal hypertension is probably attributable to sinusoidal obstruction because of compression by regenerative nodules.8 Even though data are sparse, AUY-922 datasheet other studies in patients with NRH have also suggested a mixed type of portal hypertension (pre-sinusoidal and sinusoidal).

see more In one of the case reports, a 47-year-old woman with NRH who underwent HVPG before and after splenectomy had a marked difference between WHVP and FHVP with little difference between portal venous pressure and WHVP; these findings indicated that portal hypertension in NRH was primarily sinusoidal.9 Similar data were shown by two other studies, one another single case report and the other a series of 13 cases.4,10 On the other hand, in a relatively large number of biopsy-proven cases of NRH (n = 14), Arvanitaki and Adler5 suggested that portal hypertension in patients with NRH was pre-sinusoidal. The clinical manifestations included splenomegaly, esophageal varices and variceal bleeding.5 In another recent study, 26 patients receiving 6-thioguanine for inflammatory bowel disease were evaluated with HVPG and liver biopsy.11 Six out of 24 patients (25%) with adequate liver tissue on histology had evidence of NRH. Of six patients with NRH, three had elevated (> 5 mm Hg) HVPG, two with HVPG > 10 mm Hg, whereas three others had HVPG < 5 mm Hg in spite of having clinical manifestations of portal hypertension.