Hepatic Steatosis And Necro-Inflammato ry Activity Overestimate Liver Stiffness by Transient Elastography in Staging Liver Fibrosis in Chronic Hepatitis C

Research Article

J Hepat Res. 2014;1(3): 1012.

Hepatic Steatosis And Necro-Inflammato ry Activity Overestimate Liver Stiffness by Transient Elastography in Staging Liver Fibrosis in Chronic Hepatitis C

Luca Rinaldi1, Luciano Restivo1, Barbara Guerrera1, Rosa Zampino1, Aldo Marrone1, Giuseppe Pasquale2, Rosario Zappalá3, Riccardo Nevola1 and Luigi Elio Adinolfi1*

1Department of Medical, Surgical, Neurological, Metabolic, and Geriatric Sciences, Second University of Naples, Italy

2Department of Infectious Diseases, Second University of Naples, Italy

3Evangelic Hospital "Villa Betania", Ponticelli, Naples, Italy

*Corresponding author: ToshLuigi E Adinolfi, Department of Internal Medicine, Clinical Hospital of Marcianise, Second University of Naples, 80125 Marcianise (CE), Italy

Received: August 07, 2014; Accepted: September 10, 2014; Published: September 11, 2014

Abstract

Introduction: Transient Elastography (TE) is a non-invasive method to evaluate liver fibrosis by measuring Liver Stiffness (LS). However, its role in the full management of chronic hepatitis C patients is not completely appraised as well as its limitations are scantly explored. In particular the impact of liver steatosis and necro-inflammatory activity require being more investigated. Thus, this study was aimed to further assess the reliability of TE in evaluating liver fibrosis and the impact of hepatic necro-inflammatory activity and steatosis on the performance of TE.

Patients and Methods: Enrolled were 258 consecutive patients with chronic hepatitis C who underwent to liver biopsy. Hepatic fibrosis was scored according to METAVIR, steatosis and necro-inflammatory activity were also scored. LS ranges were defined according to Castéra. Concordance between liver biopsy and TE was evaluated by Kappa index test. The performance of TE was assessed by ROC curves and by calculating AUROC. Factors independently associated with LS were weight up by logistic regression analysis.

Results: The data showed a high diagnostic accuracy of TE for severe fibrosis (≥F3) with an AUROC of 0.80 and 0.95 for F3 and F4, respectively, with a high specificity and sensitivity; but a lower efficiency in discriminate F1 from F2. At univariate analysis TE showed a relationship with liver fibrosis (p<0.0001),liver inflammation (p<0.0001) and steatosis (p<0.006).Overall, multivariate analysis showed that factors independently associate with LS were liver fibrosis (p<0.0001) and inflammation (p<0.005), whereas, steatosis (p<0.005) was independently associated with LS in patients with fibrosis lower then F3.

Conclusion: Our study confirms that TE is a reliable tool to individuate chronic hepatitis C patients with advanced liver fibrosis or cirrhosis, but it has lesser accuracy for earlier stages of liver fibrosis. Furthermore, high levels of liver necro-inflammatory activity overestimate LS and steatosis induces misevaluation of LS by TE in non-cirrhotic patients.

Keywords: Transient elastography; Chronic hepatitis C; Steatosis; Necro-inflammatory activity; Fibrosis stages; Liver stiffness

Introduction

Hepatic fibrosis is defined as the excessive accumulation of extracellular matrix proteins, resulting from chronic liver inflammatory insults [1]. Hepatic fibrosis is a key determinant of morbidity and mortality in the natural history of chronic hepatitis C in which liver cirrhosis and its complications are the final stage of the disease. Fibrosis assessment is useful to determine the prognosis of the disease, to establish the optimal timing for therapy, screening and surveillance strategies and to predict the response to treatment [2-4]. In particular, identification of patients with cirrhosis is crucial for both to start screening and treatment. Guidelines have defined two stages of liver fibrosis that notably modify the management of HCV patients in clinical practice [5] defining a significant fibrosis a stage greater than F2 according to METAVIR [6].Thus, an accurate evaluation of liver fibrosis in chronic hepatitis C has a pivotal role in its overall management. Liver biopsy is considered the best available approach to evaluate the global burden of the hepatic disease. In fact, liver biopsy is not only the gold standard in assessing liver fibrosis in chronic hepatitis C, but it is able to confirm the aetiology and to assess other significant hepatic alterations (i.e. hepatic steatosis, hepatocellular iron overload and necro-inflammatory activity). However, liver biopsy is often limited by its invasiveness and rare, but serious, complications, including bleeding, pneumothorax, and procedure-related death [6,7]. In addition, it has been reported a percentage of diagnostic inaccuracy due to sampling variability [8,9] and thus, the necessity to have an adequate sampling, which has been set up at least to 20 mm in length and 11 portal spaces [10].

In the last few years, transient elastography (TE; Fibro Scan®, EchoSens, Paris, France) has emerged as a useful, rapid and reproducible tool to measure Liver Stiffness (LS) as an accurate marker to predict liver fibrosis degree [11-13]. Overall, many studies confirmed that TE has good accuracy to diagnose advanced fibrosis and cirrhosis [14,15], although, debate remain on its full diagnostic potential in staging liver fibrosis as well as its reproducibility using the proposed cut off. In addition, TE has a number of limitations, in fact LS may be influenced by acute liver injury (as reflected by ALT flares) with a risk of overestimating LS [16,17], and also by extra hepatic cholestasis [18], irrespective of fibrosis; moreover, TE is difficult to perform in patients who are obese or who have narrow intercostals spaces [19]. It has also been reported that liver necro-inflammatory may be a factor that influence LS [20]. Additionally, it is not clear if steatosis affect the correlation between LS and fibrosis stage. Recent studies on the matter showed that steatosis induces misevaluation of LS [21,22]. However, the real impact of steatosis on LS remains debateable, because in some other studies, steatosis did not have a significant influence on LS [12]. Therefore, considering the high prevalence of steatosis and its preeminent role in both progression and management of chronic hepatitis C infection [23], additional studies are necessary to clarify whether steatosis can influence LS. For all the above considerations, it is obvious that further studies are necessary to pinpoint the full diagnostic potential as well as the limitations of TE in the diagnostic management of chronic hepatitis C patients.

Accordingly, our study was aimed to further assess the reliability of TE in evaluating liver fibrosis as well as its limitations and, in particular, the impact of liver necro-inflammatory activity and steatosis on the diagnostic performance of TE in a large series of chronic hepatitis C patients who underwent a liver biopsy.

Patients and Methods

Treatment naïve Italian consecutive patients admitted to our clinic from 2008 to 2012 for chronic hepatitis C diagnostic work-up and underwent to liver biopsy were enrolled. The inclusion criteria were: presence of HCV RNA in serum, increased ALT levels, and no previous antiviral treatment. Moreover, a patient was enrolled if liver biopsy specimen was at least 20 mm length and there were at least 11 portal spaces evaluable. Patients with decompensate cirrhosis, those who refused or had contraindication for liver biopsy, other associated causes of liver diseases, such as HBV and/or HIV positive, alcohol use ≥30g/die, autoimmune, genetic, and drug abusers were excluded.

Serum HCV-RNA positivity was evaluated by PCR HCV (Amplicor, Roche Diagnostics); viral load was evaluated by real time PCR (Monitor HCV-Amplicor; Roche Diagnostics).

At the time of liver biopsy, enrolled patients underwent to routinely blood tests for a complete liver, haematological and renal function; transientelastography was done during a period of 0-2 days prior the liver biopsy.

Local ethics committees approved the study and all patients provided consent prior to be enrolled in the study.

Histological assessment

Percutaneous echography-assisted liver biopsy was performed using the Menghini technique with an 18 G diameter needle. Biopsy samples were fixed in formalin, paraffin embedded, and stained with haematoxylin-eosin and Masson's trichrome. Biopsy specimens were analysed by an expert Pathologist (GP) in a blinded manner of the results of TE. Liver fibrosis was scored according to METAVIR [6] (F0 = no fibrosis; F1, portal fibrosis without septa; F2, portal fibrosis and a few septa; F3, numerous septa without cirrhosis; and F4, cirrhosis), and necro-Inflammatory Activity (HAI) was scored according to Knodell [24]. Steatosis was scored according to percentage of fat hepatocytes, as follows: 0, < 5%; 1, steatosis in >5-30% of hepatocytes; 2, steatosis in 31-60% of hepatocytes; 3, steatosis >60% of hepatocytes.

Transient elastography

An expert physician (RZ), in the field of echography and elastography, blinded to patient's clinical and biological data, assessed liver stiffness. The measurements were performed on the right lobe of the liver through the intercostals spaces, with the patient lying in the decubitus dorsal position, with the right hand under the head and the head turned toward the left. The tip of the probe was covered with coupling gel and placed on the skin between the ribs at the level of the right lobe of the liver. According to manufacturer, measurements were considered valid if the following three criteria were satisfactory: (1) if there was at least 10 valid shots; (2) the success rate was at least 60%; and (3) interquartile range was less than 30% of the median LSM value (IQR/LSM -30%) [25]. Ranges of stiffness related to fibrosis stages were defined according to Castera et al [11] as follow: F1: 2.5- 7.0 kPa; F2: 7.1-9.5 kPa; F3: 9.6-12.5 kPa; F4: >12.5 kPa.

Statistical analysis

Data are expressed as means ± standard deviation or median and range according with data distribution. The overall concordances as well as the concordance for each previous and subsequent score of fibrosis (e.g.F2 vs F1 and F3) between staging of liver fibrosis by liver biopsy and TE were evaluated by Kappa index test. Spearman's correlation coefficient was used to individuate variable associated with LS. All variables that were significant associated with LS were evaluated in a model of univariate analysis of variance. Logistic regression analysis was used to individuate the independent variables associated with LS. In particular, the influence of liver necro-inflammatory activity and steatosis on the performance of TE was evaluated. The diagnostic performance of TE for each score of liver fibrosis was evaluated by using Receiver-Operating Characteristic (ROC) curves and by calculating the area under the ROC curve (AUROC). A p<0.05 was assumed to denote significance. All statistical analyses were performed using SPSS software, version 13.5.

Results

Enrolled in the study were 258 out the 265 consecutive liver biopsy proven chronic hepatitis C patients, who fulfil the inclusion criteria. Table 1 shows the characteristics of the patients enrolled. The main data showed that the median age was 50 years old and male was 51%. Obesity (BMI > 30) was present in a small proportion of patients (6.2%). A large proportion of patients (65%) showed to be infected by HCV-genotype 1. Steatosis was observed in 57% of patients. HAI median was 5.0 and liver cirrhosis was observed in 14% of patients.