Elevated resistive index in the hepatic artery as a predictor of fulminant hepatic failure in patients with acute viral hepatitis: a prospective study using Doppler ultrasound

Doppler ultrasonography blood flow changes of the hepatic artery in liver transplants complicated with cholangitis

PURPOSE

Cholangitis after liver transplantation may lead to bile duct necrosis. Early diagnosis is essential to prevent graft loss. We aimed to investigate cholangitis related hepatic arterial Doppler ultrasonography findings in liver transplants.

METHODS

Patients complicated with biopsy proven cholangitis in grafts were prospectively evaluated. Vascular complications were excluded. Doppler ultrasonography parameters including hepatic arterial diameter, resistive index, volume flow, and portal vein maximum velocity were measured twice: first during cholangitis and after full recovery. Data of two groups were compared using paired samples t test and Mann-Whitney U test.

RESULTS

The mean hepatic arterial volume flow, resistive index, and diameter of 33 patients complicated with cholangitis was observed to decrease after recovery from 0.356 to 0.273 L/min (p = 0.007), from 0.64 to 0.60 (p < 0.001) and from 4.9 to 4.4 mm (p < 0.001), respectively. Portal vein maximum velocity alteration was not statistically significant (p = 0.6).

CONCLUSION

Ultrasound follow-ups after liver transplantation can give us the clue of cholangitis initiation through some altering hepatic arterial Doppler parameters. Even though these are nonspecific findings that can also be observed in vascular complications, baseline Doppler data should be saved for future comparison and considered to prevent biliary associated graft loss.

Nonalcoholic fatty liver disease and portal hypertension

Nonalcoholic fatty liver disease (NAFLD) is a substantial and growing problem worldwide and has become the second most common indication for liver transplantation as it may progress to cirrhosis and develop complications from portal hypertension primarily caused by advanced fibrosis and erratic tissue remodeling. However, elevated portal venous pressure has also been detected in experimental models of fatty liver and in human NAFLD when fibrosis is far less advanced and cirrhosis is absent. Early increases in intrahepatic vascular resistance may contribute to the progression of liver disease. Specific pathophenotypes linked to the development of portal hypertension in NAFLD include hepatocellular lipid accumulation and ballooning injury, capillarization of liver sinusoidal endothelial cells, enhanced contractility of hepatic stellate cells, activation of Kupffer cells and pro-inflammatory pathways, adhesion and entrapment of recruited leukocytes, microthrombosis, angiogenesis and perisinusoidal fibrosis. These pathological events are amplified in NAFLD by concomitant visceral obesity, insulin resistance, type 2 diabetes and dysbiosis, promoting aberrant interactions with adipose tissue, skeletal muscle and gut microbiota. Measurement of the hepatic venous pressure gradient by retrograde insertion of a balloon-tipped central vein catheter is the current reference method for predicting outcomes of cirrhosis associated with clinically significant portal hypertension and guiding interventions. This invasive technique is rarely considered in the absence of cirrhosis where currently available clinical, imaging and laboratory correlates of portal hypertension may not reflect early changes in liver hemodynamics. Availability of less invasive but sufficiently sensitive methods for the assessment of portal venous pressure in NAFLD remains therefore an unmet need. Recent efforts to develop new biomarkers and endoscopy-based approaches such as endoscopic ultrasound-guided measurement of portal pressure gradient may help achieve this goal. In addition, cellular and molecular targets are being identified to guide emerging therapies in the prevention and management of portal hypertension.

Comparison of Doppler ultrasound and transient elastography in the diagnosis of significant fibrosis in patients with nonalcoholic steatohepatitis

BACKGROUND

Liver fibrosis is an important prognostic determinant in patients with nonalcoholic steatohepatitis (NASH). Hepatic artery resistivity index (HARI) is a doppler ultrasonography (US) parameter that is used to follow up microcirculatory resistance in fatty liver. We aimed to asses whether it is possible to demonstrate significant fibrosis by means of doppler US in comparison with transient elastography (TE) and liver biopsy in NASH patients.

PATIENTS AND METHODS

A total of 63 (mean age 47.1 ± 8.4 years, 39 male, 24 female) biopsy-proven NASH patients were enrolled in this prospective study. The study population was classified into two groups: significant and no-significant fibrosis patients. Doppler US and TE were performed in two groups.

RESULTS

HARI and TE values were significantly higher in significant fibrosis group (0.81 ± 0.05 vs. 0.63 ± 0.14, p < 0.0005; 15.9 ± 4.8 vs. 6.2 ± 2.6 kilopascals, p < 0.0005; respectively). Based on the ROC curve, the optimal cut-off value of HARI for a significant fibrosis was >0.75, which yielded a sensitivity of 78% and a specificity of 75%, with the area under the curve at 0.90. The optimal cut-off value of TE for a significant fibrosis was >9.8 kilopascals, which yielded a sensitivity of 90% and a specificity of 91%, with the area under the curve at 0.95. HARI values were moderately correlated with TE values (r = 0.53, p < 0.001).

CONCLUSION

Doppler US has moderate % sensitivity and % specificity, which is lower compared with TE for the diagnosis significant fibrosis. However, it may be used as an alternative method for the assessment of fibrosis in patients with NASH who are not good candidates for TE evaluation.

Duplex Doppler Ultrasound of the Hepatic Artery: A Window to Diagnosis of Diffuse Liver Pathology

The use of Doppler sonography for evaluation of the liver is well established, and evaluation of the portal and hepatic veins in native livers, as well as the hepatic artery in transplant livers, is a standard part of the examination. Less well known, however, is that assessment hepatic of artery blood flow velocities and waveforms can permit inferences to be made about liver and system pathophysiology even in native livers. This review will illustrate that hepatic parenchymal abnormalities, as well as primary vascular abnormalities both upstream and downstream of the proper hepatic artery, can be inferred from careful interrogation of its Doppler signature during routine abdominal sonography.

Regenerative liver surgeries: the alphabet soup of emerging techniques

New surgical procedures taking advantage of the regenerative abilities of the liver are being introduced as potential curative therapies to these patients either to provide auxiliary support while the native liver recovers or undergoes hypertrophy. For patients with hepatocellular carcinoma outside of the Milan criteria or bilobar colorectal metastases liver transplantation is not an option. Fulminant hepatic failure can be treated but requires life-long immunosuppression. These complex surgical procedures require high quality and directed imaging.

Usefulness of B-mode and doppler sonography for the diagnosis of severe acute viral hepatitis A

BACKGROUND

To investigate B-mode and Doppler ultrasonography (US) features correlating with laboratory findings for the diagnosis of severe acute hepatitis (SAH) in patients with hepatitis A virus infection.

METHODS

Thirty-nine consecutive serologically proven patients were enrolled. Decreased parenchymal echotexture, periportal tracking, gallbladder wall change, and splenomegaly were assessed on B-mode images. Blood flow velocities were measured in the main portal (V(PORTAL)) and in the hepatic veins, and the hepatic venous pulsatility index was calculated. SAH was defined as high model for end-stage liver disease (MELD) score ≥ 15 with or without coagulopathy. The relationship between US features and laboratory findings was assessed, and SAH diagnosis was evaluated.

RESULTS

Serum alanine transaminase and prothrombin time were significantly different depending on the presence of gallbladder wall change and splenomegaly (p < 0.05). V(PORTAL) was inversely correlated with MELD score (r = -0.485) and several laboratory markers. The hepatic venous waveform and hepatic venous pulsatility index were significantly correlated with MELD score. For the diagnosis of SAH, the area under the receiver operating characteristic curve of V(PORTAL) was 0.798. It reached 0.869 in the patients with typical GB change.

CONCLUSIONS

Both B-mode and Doppler US correlated well with several laboratory variables and may be helpful to diagnose SAH in patients with hepatitis A virus infection.

Altered Doppler flow patterns in cirrhosis patients: an overview

Doppler ultrasonography of the hepatic vasculature is an integral part of evaluating precirrhotic and cirrhotic patients. While the reversal of the portal venous flow is a well-recognized phenomenon, other flow patterns, although not as easily understood, may play an important role in assessing the disease status. This article discusses the different characteristic flow patterns observed from the portal vein, hepatic artery, and hepatic vein in patients with liver cirrhosis or related complications and procedures. Knowledge of these different flow patterns provides additional information that may reinforce the diagnosis of cirrhosis, help in staging, and offer prognostic information for determining the direction of therapy. Doppler ultrasonography is invaluable when liver transplantation is being considered and aids in the diagnosis of cirrhosis and portal hypertension.

Hepatic artery resistance in children with obesity and fatty liver

OBJECTIVE

The present study assessed whether there is a correlation between hepatic artery resistive index (HARI) and increase of body mass index and hepatosteatosis grading in children with non-alcoholic fatty liver disease (NAFLD) reflecting hemodynamic effects of hepatosteatosis.

METHODS

Thirty three healthy children [body mass index(BMI): mean+/- standart deviation(SD), min-max: 20.1+/-1.14(18.5-23.7), 33 overweight [BMI:25.1+/-2.2 (18.5-23.7)] and 66 obese [BMI:31.1+/-2(25.6-40)] adolescents were enrolled into the study. To search the relation of HARI with fatty liver degree, study subjects subdivided into groups according to their degree of fatty liver at ultrasonography(US).

RESULTS

Increase of HARI was correlated with increase in BMI (p<0.0001, r=0.533). Increase of HARI was well correlated with increase in degree of fatty liver (p<0.0001, r=0.630).

CONCLUSION

The present study results suggest that there are positive correlations of HARI with BMI and hepatosteatosis grade in obese children with NAFLD. HARI may be a candidate parameter to determine early alarming hemodynamic changes in hepatic tissue of obese children with fatty liver before development of severe stages NAFLD.