Liver hemodynamic patterns in nonalcoholic steatosis: Doppler ultrasonography and histological evaluation.

BACKGROUND: The aim of this study was to evaluate hepatic Doppler ultrasound (US) indices for steatosis diagnosis and grading, having biopsy as reference. METHODS: Doppler and conventional US were performed in 49 healthy volunteers, without risk factors for nonalcoholic fatty liver disease (NAFLD), and in 49 patients with NAFLD and at least one risk factor: obesity, dyslipidemia and/or diabetes mellitus. Significant alcohol intake and hepatitis B or C were exclusion criteria. NAFLD patients were biopsied, and steatosis severity graded histologically. Portal Venous Pulsatility Index (PVI), Hepatic Artery Resistance Index (HARI) and Pulsatility Index (HAPI) were analyzed in hilum. Hepatic vein waveform pattern (HVWP) was classified as triphasic, biphasic or monophasic. Two pathologists analyzed histological samples. ROC curve defined sensitivity and specificity and multivariate analysis defined an equation for classifying patients. RESULTS: In NAFLD group, 89.79% had histologic criteria for non-alcoholic steatohepatitis (NASH). Mild steatosis was present in 44.89%, moderate steatosis in 38.77% and severe steatosis in 16.32%. In NAFLD group, 65.29% were obese and body mass index (BMI) had significant correlation with steatosis grading (r=0.77; P<0.0001). PVI correlated with presence of steatosis (r=-0.69, P<0.0001) as HVWP (r=-0.61, P< 0.0001). PVI ideal cutoff for predicting steatosis was 0.26 (sensitivity, 91%; specificity, 79.6%). The equation 16.15PVI+1.96HVWP enables to differentiate the healthy and the steatosis patients. HARI and HAPI could not differentiate the healthy from the steatosis group. None of the indices correlated with steatosis grading. CONCLUSIONS: Portal and hepatic vein indices allow non-invasive steatosis diagnosis but are limited to quantify it. Histology remains important for steatohepatitis diagnosis and for steatosis grading.

Bivariate and multivariate analyses of the influence of blood variables of patients submitted to Roux-en-Y gastric bypass on the stability of erythrocyte membrane against the chaotropic action of ethanol.

The stability of the erythrocyte membrane, which is essential for the maintenance of cell functions, occurs in a critical region of fluidity, which depends largely on its composition and the composition and characteristics of the medium. As the composition of the erythrocyte membrane is influenced by several blood variables, the stability of the erythrocyte membrane must have relations with them. The present study aimed to evaluate, by bivariate and multivariate statistical analyses, the correlations and causal relationships between hematologic and biochemical variables and the stability of the erythrocyte membrane against the chaotropic action of ethanol. The validity of this type of analysis depends on the homogeneity of the population and on the variability of the studied parameters, conditions that can be filled by patients who undergo bariatric surgery by the technique of Roux-en-Y gastric bypass since they will suffer feeding restrictions that have great impact on their blood composition. Pathway analysis revealed that an increase in hemoglobin leads to decreased stability of the cell, probably through a process mediated by an increase in mean corpuscular volume. Furthermore, an increase in the mean corpuscular hemoglobin (MCH) leads to an increase in erythrocyte membrane stability, probably because higher values of MCH are associated with smaller quantities of red blood cells and a larger contact area between the cell membrane and ethanol present in the medium.