Portal vein hemodynamics in patients with non-alcoholic fatty liver disease

The Portal Venous Pulsatility Index and Main Portal Vein Diameter as Surrogate Markers for Liver Fibrosis in Nonalcoholic Fatty Liver Disease and Metabolic-Dysfunction-Associated Steatotic Liver Disease

(1) Background: Despite numerous noninvasive methods for assessing liver fibrosis, effective ultrasound parameters remain limited. We aimed to identify easily measurable ultrasound parameters capable of predicting liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) and metabolic-dysfunction-associated steatotic liver disease (MASLD); (2) Methods: The data of 994 patients diagnosed with NAFLD via ultrasound at the Armed Forces Goyang Hospital were retrospectively collected from June 2022 to July 2023. A liver stiffness measurement (LSM) ≥ 8.2 kPa was classified as significant fibrosis. Liver steatosis with cardiometabolic risk factors was defined as MASLD. Two ultrasound variables, the portal venous pulsatility index (VPI) and main portal vein diameter (MPVD), were measured; (3) Results: Of 994 patients, 68 had significant fibrosis. Significant differences in VPI (0.27 vs. 0.34, p < 0.001) and MPVD (10.16 mm vs. 8.98 mm, p < 0.001) were observed between the fibrotic and non-fibrotic groups. A logistic analysis adjusted for age and body mass index (BMI) revealed that only VPI (OR of 0.955, p = 0.022, VPI on a 0.01 scale) and MPVD (OR of 1.501, p < 0.001) were significantly associated with significant liver fibrosis. In the MASLD cohort (n = 939), VPI and MPVD were associated with significant fibrosis. To achieve better accuracy in predicting liver fibrosis, we established a nomogram that incorporated MPVD and VPI. The established nomogram was validated in the test cohort, yielding an area under the receiver operating characteristic curve of 0.821 for detecting significant liver fibrosis; (4) Conclusions: VPI and MPVD, as possible surrogate markers, are useful in predicting significant fibrosis in patients with NAFLD and MASLD.

Variation in hepatic segmental portal venous pulsed wave Doppler flow distribution in patients with NAFLD: A pilot study

Purpose

To evaluate the segmental variations in portal venous pulsed wave colour Doppler flow velocity in patients with moderate to severe non-alcoholic fatty liver disease in comparison with healthy controls.

Materials and Methods

In this prospective, observational, case-control study, the maximum velocity of all the segmental branches of portal vein were evaluated on colour Doppler in patients with moderate to severe non-alcoholic fatty liver disease, and the values were compared between three groups (1) Healthy controls (n = 30), (2) non-alcoholic fatty liver disease group, that is moderate to severe fatty liver without features of portal hypertension (n = 32) and (3) non-alcoholic steatohepatitis-portal hypertension group, that is those non-alcoholic fatty liver disease patients with features of portal hypertension (n = 13).

Results

Compared to controls, non-alcoholic fatty liver disease group showed a lower velocity in all the eight segments of liver. The ratio of segment 2 to segment 7 peak portal vein maximum velocity was significantly higher in non-alcoholic fatty liver disease (1.03 ± 0.21) compared to controls (0.90 ± 0.17) and even higher in non-alcoholic steatohepatitis-Portal hypertension group (1.83 ± 0.40) with p value of 0.003.

Conclusion

Our study demonstrates the occurrence of flow redistribution occurring in cases of non-alcoholic fatty liver disease patients with the left lobe receiving higher portal venous flow. This flow redistribution was even more pronounced in a subset of non-alcoholic fatty liver disease patients who developed features of portal hypertension.

Venous Doppler to Assess Congestion: A Comprehensive Review of Current Evidence and Nomenclature

Organ congestion from venous hypertension is an important pathophysiological mechanism mediating organ injury in several clinical contexts including critical illness, congestive heart failure and end-stage chronic kidney disease. However, the practical evaluation of venous congestion is often challenging at the bedside because of the limitations of traditional methods. Point-of-care ultrasound (POCUS) enables the clinician to assess venous velocity profiles during the cardiac cycle using Doppler modalities. Venous Doppler profile abnormalities at multiple sites are detected when elevated venous pressure results in hemodynamic changes within the systemic venous circulation. The detection of these abnormal Doppler profiles may identify patients with clinically significant systemic venous congestion. These patients have been reported to be at increased risk of medical complications. Improving the evaluation of venous congestion may lead to individualized treatment and improved patient outcomes. In this review, we describe the physiologic principles necessary to understand venous Doppler assessment. We also propose a nomenclature for the description of venous Doppler profiles. Finally, we provide a narrative review of the current clinical evidence related to use of venous Doppler assessment in various clinical contexts.

Portal Hypertension in Nonalcoholic Fatty Liver Disease: From Pathogenesis to Clinical Practice

Portal hypertension in nonalcoholic fatty liver disease (NAFLD) mostly occur in cirrhotic stage. However, several experimental and clinical studies showed evidence of portal hypertension in NAFLD without significant or advance fibrosis. This early development of portal hypertension in NAFLD is associated with liver sinusoidal contraction by hepatocellular lipid accumulation and ballooning, which is also accompanied by capillarization and dysfunction of liver sinusoidal endothelial cells. Both of these impaired mechanical and molecular components can cause an increase in intrahepatic vascular resistance which lead to the increase of portal pressure in the absence of significant liver fibrosis. Extrahepatic factors such as insulin resistance and gut dysbiosis may also contribute to liver sinusoidal endothelial dysfunction and early portal hypertension in NAFLD. The clinical impact of early portal hypertension in NAFLD is still unclear. However, clinical tools for diagnosis and monitoring of portal hypertension in NAFLD are being investigated to predict high-risk patients and to guide therapy.

Superb Microvascular Imaging-Based Vascular Index to Assess Adult Hepatic Steatosis: A Feasibility Study

The aim of the study was to assess the feasibility of using a superb microvascular imaging-based vascular index (SMI-VI) for evaluating adult hepatic steatosis. We prospectively compared liver parenchyma SMI-VI (color pixels/total pixels in the region of interest), portal vein velocity, hepatic artery Doppler parameters (peak systolic velocity, end diastolic velocity, resistive index) and serum lipid and alanine aminotransferase (ALT) levels between 16 normal livers and 34 steatotic livers using magnetic resonance imaging-proton density fat fraction (MRI-PDFF) as the reference. On the basis of a two-tailed t-test, differences in SMI-VI, portal vein velocity, MRI-PDFF and ALT between normal (MRI-PDFF <5%) and steatotic (MRI-PDFF ≥5%) livers were statistically significant (p < 0.02), whereas hepatic artery Doppler parameters and triglyceride levels were not (p > 0.05). We observed an inverse correlation of SMI-VI with MRI-PDFF (r = -0.88). With 0.19 as the best cutoff value, the area under the receiver operating characteristic curve, sensitivity and specificity of SMI-VI for determining ≥mild (MRI-PDFF ≥5%) non-alcoholic fatty liver disease (NAFLD) were 0.95, 96% and 94%, respectively. Our results indicate the feasibility of using SMI-VI to assess adult hepatic steatosis. SMI-VI is a potential surrogate marker in the screening for NAFLD.

PBPK modeling of impact of nonalcoholic fatty liver disease on toxicokinetics of perchloroethylene in mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD), a major cause of chronic liver disease in the Western countries with increasing prevalence worldwide, may substantially affect chemical toxicokinetics and thereby modulate chemical toxicity.

OBJECTIVES

This study aims to use physiologically-based pharmacokinetic (PBPK) modeling to characterize the impact of NAFLD on toxicokinetics of perchloroethylene (perc).

METHODS

Quantitative measures of physiological and biochemical changes associated with the presence of NAFLD induced by high-fat or methionine/choline-deficient diets in C57B1/6 J mice are incorporated into a previously developed PBPK model for perc and its oxidative and conjugative metabolites. Impacts on liver fat and volume, as well as blood:air and liver:air partition coefficients, are incorporated into the model. Hierarchical Bayesian population analysis using Markov chain Monte Carlo simulation is conducted to characterize uncertainty, as well as disease-induced variability in toxicokinetics.

RESULTS

NAFLD has a major effect on toxicokinetics of perc, with greater oxidative and lower conjugative metabolism as compared to healthy mice. The NAFLD-updated PBPK model accurately predicts in vivo metabolism of perc through oxidative and conjugative pathways in all tissues across disease states and strains, but underestimated parent compound concentrations in blood and liver of NAFLD mice.

CONCLUSIONS

We demonstrate the application of PBPK modeling to predict the effects of pre-existing disease conditions as a variability factor in perc metabolism. These results suggest that non-genetic factors such as diet and pre-existing disease can be as influential as genetic factors in altering toxicokinetics of perc, and thus are likely contribute substantially to population variation in its adverse effects.

Clinical Outcome of Residual Liver Volume and Hepatic Steatosis After Right-Lobe Living-Donor Hepatectomy

Background

We examine how residual liver volume (RLV) and hepatic steatosis (HS) of living liver donors affect the regeneration process and clinical outcomes.

Material/Methods

We longitudinally studied 58 donors who underwent right-lobe hepatectomy during the period February 2014 to February 2015 at a single medical institution. The patients were classified based on RLV (30–35%, 35–40%, 40–50%) subgroups and HS (<10%, 10–30%, 30–50%) subgroups. Clinical parameters such as clinical outcome, liver volumetric recovery (LVR,%) rate and remnant left-liver (RLL,%) growth rate were collected for analysis.

Results

The clinical features of postoperative peak total bilirubin (p=.024) were significant in the 3 RLV subgroups. Body mass index (p=.017), preoperative alanine transaminase (p<.001), and pleural effusion (p=.038) were significant in the 3 HS subgroups. The LVR rate and RLL growth rate equations showed significant variation in regeneration among the 3 RLV subgroups. The LVR rate and RLL growth rate equations did not show significant variation in regeneration among the 3 HS subgroups.

Conclusions

Hyperbilirubinemia was a risk factor in the small-RLV group, and a large amount of pleural effusion was a risk factor in the steatosis 30–50% group. Hepatic steatosis subgroups did not show significantly different degrees of regeneration. The safety of living donors was a major concern while we compiled the extended living-donor criteria presented in this paper.

Portal Venous Pulsatility Index: A Novel Biomarker for Diagnosis of High-Risk Nonalcoholic Fatty Liver Disease

OBJECTIVE. The purpose of this study was to assess the accuracy of portal vein pulsatility for noninvasive diagnosis of high-risk nonalcoholic fatty liver disease (NAFLD). MATERIALS AND METHODS. This retrospective study included patients with biopsy-proven diagnosis of NAFLD who underwent duplex Doppler ultrasound assessment of the main portal vein within 1 year of liver biopsy (January 2014 to February 2018). Doppler ultrasound images were reviewed. The spectral waveform was used to measure the maximum (V_max) and minimum (V_min) velocity of blood in the portal veins. Venous pulsatility index (VPI) defined as (V_max - V_min) / V_max was calculated. ROC curve analysis was used to calculate AUC as a measure of accuracy to determine the value of this index for diagnosis of high-risk NAFLD and compared with that of the following four clinical decision aids: NAFLD fibrosis score (FS), fibrosis-4 index (FIB-4), BARD score (body mass index, aspartate aminotransferase [AST]-to-alanine aminotransferase ratio, diabetes mellitus), and AST-to-platelet ratio index (APRI). The value of adding VPI to these indexes was also investigated. RESULTS. Of 123 study subjects, 33 (26.8%) had high-risk NAFLD and were found to have a lower VPI than the other 90 subjects (0.19 vs 0.32; p < 0.001). VPI, NAFLD FS, FIB-4, and APRI had statistically significant diagnostic values for high-risk NAFLD. VPI had the highest optimism-corrected AUC (VPI, 0.84 [95% CI, 0.77-0.91]; NAFLD FS, 0.74 [95% CI, 0.63-0.83]; FIB-4, 0.81 [95% CI, 0.72-0.89]; APRI, 0.73 [95% CI, 0.61-0.82]). Addition of VPI to any of the four scoring systems significantly improved the diagnostic value of the score for high-risk NAFLD. CONCLUSION. VPI may be an accurate noninvasive biomarker for diagnosis of high-risk NAFLD.

Characterization of the Normal Portal and Hepatic Blood Flow of Adult Holstein-Friesian Cows

Simple summary

Knowledge of physiological portal and hepatic blood flow in cattle is essential for the use of Doppler ultrasound for diagnostic purposes. In this paper, we describe a protocol for the systematic ultrasonography evaluation of the portal and hepatic system in cattle and report the reference values for healthy cows.

Abstract

In the past, hepatic blood flow in cows was invasively characterized to investigate different pathologies and physiological conditions. However, hepatic blood flow can be easily evaluated with transabdominal Doppler ultrasound. Sixteen healthy adult non-lactating, non-pregnant Holstein-Friesian cows were examined using B-mode and Doppler ultrasound between the right flank and 9^th intercostal space to establish the best approach to the different parts of the portal and hepatic vein systems, and determine normal blood flow characteristics. The main portal vein was characterized by a turbulent, high-velocity flow due to the opposing confluence of the splenic and cranial mesenteric veins, while hepatic and caudal vena cava veins have laminar blood flow, in which the phasicity is considered mainly respiratory in origin. Reference values were determined in relation to the anatomical point of observation. In conclusion, transabdominal Doppler ultrasound of the portal system is a simple technique that allows non-invasive characterization of portal and hepatic blood haemodynamics in cows.

Portal venous velocity affects liver regeneration after right lobe living donor hepatectomy

OBJECTIVES

We investigated whether chronological changes in portal flow and clinical factors play a role in the liver regeneration (LR) process after right donor-hepatectomy.

MATERIALS AND METHODS

Participants in this prospective study comprised 58 donors who underwent right donor-hepatectomy during the period February 2014 to February 2015 at a single medical institution. LR was estimated using two equations: remnant left liver (RLL) growth (%) and liver volumetric recovery (LVR) (%). Donors were classified into an excellent regeneration (ER) group or a moderate regeneration (MR) group based on how their LR on postoperative day 7 compared to the median value.

RESULTS

Multivariate analysis revealed that low residual liver volume (OR = .569, 95% CI: .367- .882) and high portal venous velocity in the immediate postoperative period (OR = 1.220, 95% CI: 1.001-1.488) were significant predictors of LR using the RLL growth equation; high portal venous velocity in the immediate postoperative period (OR = 1.325, 95% CI: 1.081-1.622) was a significant predictor of LR using the LVR equation. Based on the two equations, long-term LR was significantly greater in the ER group than in the MR group (p < .001).

CONCLUSION

Portal venous velocity in the immediate postoperative period was an important factor in LR. The critical time for short-term LR is postoperative day 7; it is associated with long-term LR in donor-hepatectomy.

Diabetes Mellitus and Liver Surgery: The Effect of Diabetes on Oxidative Stress and Inflammation

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycaemia and high morbidity worldwide. The detrimental effects of hyperglycaemia include an increase in the oxidative stress (OS) response and an enhanced inflammatory response. DM compromises the ability of the liver to regenerate and is particularly associated with poor prognosis after ischaemia-reperfusion (I/R) injury. Considering the growing need for knowledge of the impact of DM on the liver following a surgical procedure, this review aims to present recent publications addressing the effects of DM (hyperglycaemia) on OS and the inflammatory process, which play an essential role in I/R injury and impaired hepatic regeneration after liver surgery.

Laboratory Tests, Liver Vessels Color Doppler Sonography, and FibroScan Findings in Patients with Nonalcoholic Fatty Liver Disease: An Observation Study

Objective

Determination of the amount of parenchymal damage in nonalcoholic fatty liver disease (NAFLD) is crucial to choose the best treatment and management.

Aim

Here, the associations between laboratory data and severity of steatosis and fibrosis plus hepatic vessel Doppler indices in NAFLD patients were investigated.

Patients and Methods

Fifty patients (20 males and 30 females) with NAFLD criteria were enrolled. Fatty liver was graded by sonography (SGFL) and FibroScan (FGFL). In addition, liver fibrosis was graded through FGLF. Damages to the portal, hepatic, and splenic veins were evaluated by color Doppler/dopplex. Serum liver enzymes and C-reactive protein (CRP) were also measured.

Results

Significant association existed between SGFL and FGFL (P = 0.006). Portal vein pulsatility index (PI) and phasicity plus the triphasic and monophasic pattern of hepatic veins significantly associated with fatty liver grade evaluated by sonography. Splenic vein Peak systolic velocity and PI showed significant association with FGFL. Eventually, elevated liver enzymes and CRP significantly correlated with FGLF.

Conclusion

We found that the severity of fatty liver is correlated with hepatic and portal veins damages; however, the degree of parenchymal fibrosis was independent to these indices and can be directly evaluated by FGFL. In addition, elevated liver enzymes and CRP correlated with the degree of fibrosis.

Risk and Prognosis of Acute Liver Injury Among Hospitalized Patients with Hemodynamic Instability: A Nationwide Analysis

Risk and Prognosis of Acute Liver Injury Among Hospitalized Patients with Hemodynamic Instability: A Nationwide Analysis Introduction and aim. Critically ill patients in states of circulatory failure are at risk of acute liver injury, from mild elevations in aminotransferases to substantial rises consistent with hypoxic hepatitis or "shock liver". The present study aims to quantify the national prevalence of acute liver injury in patients with hemodynamic instability, identify risk factors for its development, and determine predictors of mortality.

MATERIAL AND METHODS

The 2009-2010 Nationwide Inpatient Sample was interrogated using ICD-9-CM codes for hospital admissions involving states of hemodynamic lability. Multivariable logistic regression was used to evaluate the risks of acute liver injury and death in patients with baseline liver disease, congestive heart failure, malnutrition, and HIV.

RESULTS

Of the 2,865,446 patients identified in shock, 4.60% were found to have acute liver injury. A significantly greater proportion of patients with underlying liver disease experienced acute liver injury (22.03%) and death (28.47%) as compared to those without liver disease (3.18% and 18.82%, respectively). The odds of developing acute liver injury were increased in all baseline liver diseases studied, including all-cause cirrhosis, hepatitis B, hepatitis C, alcoholic liver disease, and non-alcoholic fatty liver disease, as well as in congestive heart failure and malnutrition. All-cause cirrhosis and alcoholic liver disease, however, conferred the greatest risk. Similar trends were seen with mortality. HIV was not a predictor for acute liver injury.

CONCLUSION

Liver injury is a major concern among patients with protracted circulatory instability, especially those suffering from underlying liver disease, heart failure, or malnutrition.

Sonographic Evaluation of Liver Hemodynamic Indices in Overweight and Obese Dogs

Background

Hepatic circulatory disturbances have been associated with obesity and fatty liver in humans. In the veterinary literature, however, there is limited information regarding the effects of different body condition scores (BCS) on liver hemodynamic indices in dogs.

Objectives

To investigate the influence of BCS on liver hemodynamic indices.

Animals

Fifty‐three client‐owned dogs of various breeds were included.

Methods

Prospective observational study. Dogs were divided into 3 BCS groups using a 5‐point scale: G1 – 12 ideal dogs, G2 – 21 overweight dogs, G3 – 20 obese dogs. Mean portal velocity (MPV), portal blood flow volume (PBFV), portal congestion index (PCI), hepatic artery resistivity index (HARI), and hepatic vein (HV) spectral wave were obtained by pulsed Doppler sonography. Alkaline phosphatase (ALP), gamma‐glutamyl transferase (GGT), and alanine aminotransferase (ALT) activities were determined. Liver enzymes activities and liver hemodynamic indices were compared among groups.

Results

Obese dogs had lower MPV, higher percentage of abnormal hepatic vein spectral wave and higher median ALP activity than did ideal dogs (P < 0.05). Overweight and obese dogs had lower PBFV than ideal dogs (P < 0.01). Overweight dogs had higher median GGT activity than ideal dogs (P < 0.05). No difference was observed for PCI, HARI and median ALT activity among the groups.

Conclusions and Clinical Importance

Obesity was associated with changes in portal vein indices and in HV spectral wave. These changes were accompanied by significant differences in some liver enzymes activities and could be a sign of early liver disease.

Non-alcoholic fatty liver disease, to struggle with the strangle: Oxygen availability in fatty livers

Nonalcoholic fatty liver diseases (NAFLD) is one of the most common chronic liver disease in Western countries. Oxygen is a central component of the cellular microenvironment, which participate in the regulation of cell survival, differentiation, functions and energy metabolism. Accordingly, sufficient oxygen supply is an important factor for tissue durability, mainly in highly metabolic tissues, such as the liver. Accumulating evidence from the past few decades provides strong support for the existence of interruptions in oxygen availability in fatty livers. This outcome may be the consequence of both, impaired systemic microcirculation and cellular membrane modifications which occur under steatotic conditions. This review summarizes current knowledge regarding the main factors which can affect oxygen supply in fatty liver.

Metabolic syndrome and the hepatorenal reflex

Insufficient hepatic O₂ in animal and human studies has been shown to elicit a hepatorenal reflex in response to increased hepatic adenosine, resulting in the stimulation of renal as well as muscle sympathetic nerve activity and activating the renin angiotensin system. Low hepatic ATP, hyperuricemia, and hepatic lipid accumulation reported in metabolic syndrome (MetS) patients may reflect insufficient hepatic O₂ delivery, potentially accounting for the sympathetic overdrive associated with MetS. This theoretical concept is supported by experimental results in animals fed a high fructose diet to induce MetS. Hepatic fructose metabolism rapidly consumes ATP resulting in increased adenosine production and hyperuricemia as well as elevated renin release and sympathetic activity. This review makes the case for the hepatorenal reflex causing sympathetic overdrive and metabolic syndrome in response to exaggerated splanchnic oxygen consumption from excessive eating. This is strongly reinforced by the fact that MetS is cured in a matter of days in a significant percentage of patients by diet, bariatric surgery, or endoluminal sleeve, all of which would decrease splanchnic oxygen demand by limiting nutrient contact with the mucosa and reducing the nutrient load due to loss of appetite or dietary restriction.

Metabolic syndrome and the hepatorenal reflex

Insufficient hepatic O₂ in animal and human studies has been shown to elicit a hepatorenal reflex in response to increased hepatic adenosine, resulting in stimulation of renal as well as muscle sympathetic nerve activity and activating the renin angiotensin system. Low hepatic ATP, hyperuricemia, and hepatic lipid accumulation reported in metabolic syndrome (MetS) patients may reflect insufficient hepatic O₂ delivery, potentially accounting for the sympathetic overdrive associated with MetS. This theoretical concept is supported by experimental results in animals fed a high fructose diet to induce MetS. Hepatic fructose metabolism rapidly consumes ATP resulting in increased adenosine production and hyperuricemia as well as elevated renin release and sympathetic activity. This review makes the case for the hepatorenal reflex causing sympathetic overdrive and metabolic syndrome in response to exaggerated splanchnic oxygen consumption from excessive eating. This is strongly reinforced by the fact that MetS is cured in a matter of days in a significant percentage of patients by diet, bariatric surgery, or endoluminal sleeve, all of which would decrease splanchnic oxygen demand by limiting nutrient contact with the mucosa and reducing the nutrient load due to the loss of appetite or dietary restriction.

Assessment of Portal Venous and Hepatic Artery Haemodynamic Variation in Non-Alcoholic Fatty Liver Disease (NAFLD) Patients

INTRODUCTION

Non-Alcoholic Fatty Liver Disease (NAFLD) has various spectrums of liver diseases like isolated fatty liver, steatohepatitis and cirrhosis usually progressing in a linear fashion. In this process they are known to cause certain haemodynamic changes in the portal flow and hepatic artery flow.

AIM

The aim of the study was to study these haemodynamic changes in patients with NAFLD and to correlate it with the disease severity.

MATERIALS AND METHODS

Ninety patients diagnosed to have NAFLD based on ultrasound abdomen (30 each in grade1, grade2 and grade3 NAFLD) and 30 controls (Normal liver on ultrasound abdomen) were subjected to portal vein and hepatic artery Doppler study. Peak maximum velocity (Vmax), Peak minimum velocity (Vmin), Mean flow velocity (MFV), and Vein pulsality index (VPI) of the portal vein and hepatic artery resistivity index (HARI) of the hepatic artery were the doppler parameters which were assessed. Liver span was also assessed both for the fatty liver and controls.

RESULTS

The mean Vmax, Vmin, MFV and VPI of the portal vein in patients with NAFLD was 12.23±1.74cm/sec, 9.31±1.45cm/sec, 10.76±1.48cm/sec, and 0.24±0.04 as compared to 14.05±2.43cm/sec, 10.01±2.27cm/sec, 12.23±2.47cm/sec, 0.3±0.08 in controls respectively. All these differences were statistically significant except for Vmin. The Mean HARI in patients with fatty liver was 0.65±0.06 when compared to controls of 0.75±0.06 (p=0.001). HARI (r-value of -0.517) had a better negative correlation followed by VPI (r-value of -0.44) and Vmax (r-value of -0.293) with the severity of NAFLD. MFV had a very weak negative correlation (r-value of -0.182) with the severity of NAFLD.

CONCLUSION

The Vmax, MFV, VPI and HARI were significantly less when compared to controls suggesting a reduced portal flow and an increased hepatic arterial flow in patients with NAFLD. Among the parameters, HARI correlated better with the severity of NAFLD followed by VPI.

Effects of fat accumulation in the liver on hemodynamic variables assessed by Doppler ultrasonography

PURPOSE

To investigate the effect of various degrees of fatty liver infiltration on hepatic hemodynamics using Doppler ultrasonography.

METHODS

We included 40 patients with hepatic steatosis and 20 healthy volunteers. Hepatic steatosis was quantified by a chemical shift MRI. Hepatic artery peak systolic and end-diastolic velocity, resistance index (RI) and pulsatility index (PI), hepatic vein RI and PI, portal vein RI, PI, congestion index, and peak maximum velocity were evaluated by Doppler ultrasonography. The hepatic vein waveforms were classified as triphasic, biphasic, or monophasic. Kruskal-Wallis test was performed for comparing more than two groups. If significant differences were found, Mann-Whitney U test with Bonferroni correction was performed for pair-wise comparisons. Pearson &gch;(2) and Fisher's exact tests were used to compare categorical variables.

RESULTS

According to MRI, 15 patients had mild, 14 patients had moderate, and 11 patients had severe fatty infiltration. Portal vein peak maximum velocity was median: 19.8 (range 12-33.3), 21.1 (8-41.8), 16.6 (10.6-24.9), and 29.2 (14.1-40.4) cm/s. Congestion index was 0.05 (0.02-0.16), 0.07 (0.01-0.17), 0.11 (0.06-0.24), and 0.05 (0.02-0.16). Hepatic artery RI was 0.75 (0.56-1.00), 0.66 (0.52-0.87), 0.83 (0.38-1.00), and 0.76 (0.48-2.76), and PI was 1.83 (0.90-3.13), 1.38 (1.04-2.63), 1.97 (0.86-2.90), and 1.82 (0.70-2.90) (p = .046 and p = .036) in the mild, moderate, severe steatosis, and control groups, respectively. The rate of triphasic hepatic vein waveforms was higher in controls than in patients with severe steatosis.

CONCLUSIONS

Portal vein flow velocity decreases in severe hepatic steatosis when compared with controls.

The Doppler ultrasonographic evaluation of hemodynamic changes in hepatic vascular structures in patients with hepatosteatosis

Background

The hemodynamic changes in hepatic vascular structures of hepatosteatosis patients were examined using Doppler ultrasonography.

Material/Methods

Ninety hepatosteatosis patients, classified as mild, moderate or severe, and 30 healthy volunteers were included in this 120-person study. The height, weight, liver size, blood lipids and blood liver function tests of the subjects were measured. Those values were compared in the patient and control groups. In the patient and control groups, color duplex Doppler ultrasonography was used to examine portal vein peak velocity, portal vein flow volume, hepatic artery resistive index (RI), hepatic artery pulsatility index (PI) and hepatic artery flow volume.

Results

Similarly to the degree of hepatosteatosis, increases in body mass index, liver size, liver enzyme levels and blood lipid levels were statistically significant (p<0.05). While the difference in portal vein peak velocity in the hepatosteatosis and control groups was not statistically significant, there was an increasing reduction in the degree of steatosis (p>0.05). As the degree of hepatosteatosis increased, there was a reduction in hepatic artery flow volume, portal vein flow volume and total flow volume that was not statistically significant. In the mild hepatosteatosis group, hepatic artery RI and PI values were statistically significantly lower than in the other groups (p<0.05). In the severe hepatosteatosis group, although the hepatic artery RI and PI values were not statistically significant, there was a minimal increase compared to the other groups.

Conclusions

It is believed that those results were caused by a reduction in liver compliance and hepatic vascular compliance, in addition to resistance increase in vascular structures.

Comparison of portal vein doppler indices and hepatic vein doppler waveform in patients with nonalcoholic fatty liver disease with healthy control

BACKGROUND

The purpose of the present study is to investigate the association of nonalcoholic fatty liver disease (NAFLD) with the doppler waveform pattern of hepatic veins and portal vein doppler indices.

OBJECTIVES

This assay may be useful in evaluating the natural course of NAFLD and monitor treatment efficacy on follow-up.

PATIENTS AND METHODS

This case control study was performed in 31 patients with NAFLD and 31 normal healthy adults who served as the control group. The patients presented with elevated liver enzymes levels (ALT/AST) and hyperechogenic livers in the B-mode ultrasonography examination. Eleven patients had a liver biopsy. After an 8-hour fast,B-mode and duplex doppler ultrasonography were performed, and the waveform patterns of the right hepatic vein, portal vein diameter, grade of fatty liver, portal vein pulsatility index (VPI), and mean flow velocity (MFV) were measured.

RESULTS

VPI and MFV values were 0.42 ± 0.92 and 17.27 ± 5.34 cm/second, respectively, in the control group and 0.25 ± 0.50 and 12.82 ± 4.32 cm/second in patients with NAFLD (P< 0.01). The frequency of abnormal hepatic vein doppler waveform patterns (biphasic or monophasic) was significantly higher in patients with NAFLD (55.2%) versus control subjects (3.2%) (P < 0.001). There was no correlation between the degree of fat infiltration and VPI (P = 0.714), MFV (P = 0.911), or hepatic vein waveform pattern (P = 0.197). We found no correlation between liver enzyme levels and MFV or VPI. However, the rate of abnormal hepatic vein was higher in patients with enzyme levels that exceeded twice the normal value (P = 0.05).

CONCLUSIONS

Patients with NAFLD have a high rate of abnormal hepatic vein doppler waveform patterns, and decreased VPI and MFV are suggestive of reduced vascular compliance in the liver. Elevated liver enzymes levels do not influence VPI or MFV, but patients with abnormal enzymes have higher rates of abnormal hepatic vein doppler waveform patterns.

Elevated peripheral blood monocyte fraction in nonalcoholic fatty liver disease

An elevated white blood cell (WBC) count is associated with nonalcoholic fatty liver disease (NAFLD); however, a leukocyte subtype that is involved in the pathogenesis of NAFLD is not known. This study was conducted to investigate the association between NAFLD and WBC subtype fractions (%) among healthy elderly Koreans. A total of 794 subjects who underwent a health check-up were investigated. After excluding excessive alcohol intake and other liver diseases, NAFLD was diagnosed based on sonographic findings: hyperechogenecity of liver tissue, difference of echogenicity between liver and kidney, and visibility of vascular structures. The prevalence of NAFLD among entire cohort was 39.0% (310/794). The presence of NAFLD was significantly associated with higher blood WBC counts (5,485 ± 1073 vs. 5,230 ± 995 per mm(3), p = 0.001) and monocyte fraction (6.08 ± 2.40% vs. 5.12 ± 1.31%, p < 0.001). The multiple logistic regression analysis, after controlling confounders, including age, gender, body mass index, systolic and diastolic blood pressure, fasting blood glucose, alanine aminotransferase, triglyceride, and high-density lipoprotein cholesterol, showed that the prevalence risk of NAFLD was increased significantly according to the monocyte fraction quartiles: odds ratios (ORs) and 95% confidence intervals (CIs) for NAFLD were 1.00, 2.75 (1.63-4.62), 2.84 (1.67-4.84) and 5.17 (3.03-8.83), respectively. There were no significant associations between NAFLD and the total WBC count quartiles in this model. These results indicate that the elevated peripheral blood monocyte fraction is associated with NAFLD. The monocyte fraction might be a useful marker for NAFLD.

Liver fat content in type 2 diabetes: relationship with hepatic perfusion and substrate metabolism

OBJECTIVE

Hepatic steatosis is common in type 2 diabetes. It is causally linked to the features of the metabolic syndrome, liver cirrhosis, and cardiovascular disease. Experimental data have indicated that increased liver fat may impair hepatic perfusion and metabolism. The aim of the current study was to assess hepatic parenchymal perfusion, together with glucose and fatty acid metabolism, in relation to hepatic triglyceride content.

RESEARCH DESIGN AND METHODS

Fifty-nine men with well controlled type 2 diabetes and 18 age-matched healthy normoglycemic men were studied using positron emission tomography to assess hepatic tissue perfusion, insulin-stimulated glucose, and fasting fatty acid metabolism, respectively, in relation to hepatic triglyceride content, quantified by proton magnetic resonance spectroscopy. Patients were divided into two groups with hepatic triglyceride content below (type 2 diabetes-low) or above (type 2 diabetes-high) the median of 8.6%.

RESULTS

Type 2 diabetes-high patients had the highest BMI and A1C and lowest whole-body insulin sensitivity (ANOVA, all P < 0.001). Compared with control subjects and type 2 diabetes-low patients, type 2 diabetes-high patients had the lowest hepatic parenchymal perfusion (P = 0.004) and insulin-stimulated hepatic glucose uptake (P = 0.013). The observed decrease in hepatic fatty acid influx rate constant, however, only reached borderline significance (P = 0.088). In type 2 diabetic patients, hepatic parenchymal perfusion (r = -0.360, P = 0.007) and hepatic fatty acid influx rate constant (r = -0.407, P = 0.007) correlated inversely with hepatic triglyceride content. In a pooled analysis, hepatic fat correlated with hepatic glucose uptake (r = -0.329, P = 0.004).

CONCLUSIONS

In conclusion, type 2 diabetic patients with increased hepatic triglyceride content showed decreased hepatic parenchymal perfusion and hepatic insulin mediated glucose uptake, suggesting a potential modulating effect of hepatic fat on hepatic physiology.

Prevalence of ultrasound-diagnosed non-alcoholic fatty liver disease in a hospital cohort and its association with anthropometric, biochemical and sonographic characteristics

Non-alcoholic fatty liver disease (NAFLD) is considered as the most common liver disease in Western countries with still rising prevalence due to a lifestyle favoring the development of the metabolic syndrome.

AIM

To investigate the prevalence of ultrasound-diagnosed NAFLD in patients with referral for sonographic examination of the abdomen, and to determine risk factors.

METHODS

After exclusion of patients with known liver disease or risk factors for secondary NAFLD, a total of 155 arbitrarily selected patients (mean age 53.6±17.4 years; 52.6% male) from the interdisciplinary ultrasound department of a German University Hospital were included in this prospective study. Each patient underwent a standardized ultrasound, anthropometric and biochemical examination.

RESULTS

The prevalence of ultrasound-diagnosed NAFLD was 40.0%. NAFLD-patients had significantly higher body mass index (BMI) and waist-to-hip ratio, higher rates of reported hypertension and diabetes mellitus, and lower HDL cholesterol serum levels. Furthermore, NAFLD-patients revealed significantly higher serum ALT levels (23.2±22.1 U/l vs. 15.0±8.2 U/l; p=0.001), lower AST/ALT ratio (1.76±0.79 vs. 2.11±0.94; p=0.019), and notably, decreased flow in the portal vein (22.9±6.3 cm/s vs. 26.7±10.5 cm/s; p=0.011). Multivariate analysis revealed BMI (odds ratio (OR): 14.05; 95% Confidence interval (CI): 3.3-59.8), AST/ALT ratio (OR: 0.39; CI: 0.18-0.82), and HDL-C (OR: 4.33; CI: 1.6-11.9) as independent risk factors.

CONCLUSIONS

Ultrasound-diagnosed NAFLD is frequent in patients with referral for ultrasound examination of the abdomen, and our findings further support that NAFLD is the hepatic manifestation of the metabolic syndrome with obesity being the most important risk factor.

New imaging techniques for non-alcoholic steatohepatitis

No imaging modality has yet been proven to reliably differentiate simple hepatic steatosis from steatohepatitis. This review focuses on the predominant non-nuclear imaging modalities available to clinicians at the present time. The key feature of the techniques outlined in this review that demonstrate the most interesting results have one thing in common: imaging is not performed in a passive manner but is undertaken as a method to investigate functional differences between simple hepatic steatosis and steatohepatitis based upon the current working model for pathogenesis and progression. The purpose of this article is to review the strengths and weakness of current clinical and experimental imaging modalities for noninvasive detection of NAFLD, with an emphasis on NASH.