Normal controlled attenuation parameter values: a prospective study of healthy subjects undergoing health checkups and liver donors in Korea

Evaluation of Controlled Attenuation Parameter as a Tool for Assessment of Hepatic Steatosis in Living Liver Donors

Background

Currently, there is an absence of a standardised protocol for the preoperative detection of hepatic steatosis (HS) in living liver donors. A steatotic liver graft jeopardises the outcome of the recipient with multiple potential complications. Vibration-controlled transient elastography (Fibroscan®) provides a controlled attenuation parameter (CAP), which we have utilised in our assessment of HS in living liver donors. This approach offers a promising avenue for the advancement of preoperative evaluation protocols.

Methods

In the period spanning from October 2022 to July 2024, a cohort of 67 liver donors were subjected to preoperative vibration-controlled transient elastography (Fibroscan®) and either preoperative or intraoperative liver biopsy. HS was defined as a fat content exceeding 10%. CAP readings were juxtaposed with liver biopsy results for the diagnosis of HS. Donors were categorised into three categories with HS <5%, 5-10% and those with HS >10% were rejected as per our institutional protocol. This facilitated a comprehensive evaluation of HS in the context of living donor liver transplantation.

Results

CAP was very accurate in detecting HS, with an area under the receiver operating characteristic curve of 0.99 (P < 0.05). Statistical analysis determined that a CAP cutoff value of 266 dB/m provides a sensitivity of 100% and a specificity of 98.4% for predicting HS >10%. Corresponding positive predictive value (PPV) is 85.71%, while the negative predictive value is 100%. Univariate analysis determined body mass index (BMI), age and serum triglyceride levels were associated with CAP; however, multivariate linear regression revealed an association with only BMI (P < 0.001) and age (P < 0.002). When a lower fat threshold of 5% was considered to define HS with the same cut off of CAP, the sensitivity reduced to 66.7% and specificity was 98.3% The recipients of donors with HS of 5%-10% did not show any negative outcomes.

Conclusion

CAP demonstrates significant potential as a predictive tool for hepatic steatosis (HS) in living liver donors. Notably, BMI and age have been identified as independent factors associated with CAP values.

Short-term outcome of bariatric surgery on nonalcoholic fatty liver disease: a Korean perspective

Purpose

Obesity is associated with nonalcoholic fatty liver disease, one of the most common causes of chronic liver disease. We aimed to demonstrate the effectiveness of bariatric surgery for hepatic steatosis and fibrosis in Korean patients.

Methods

A total of 32 consecutive patients were enrolled in this study. Hepatic steatosis and liver fibrosis were assessed before surgery and 6 months after surgery using transient elastography and serologic panels.

Results

Thirteen patients (40.6%) were male and 19 (59.4%) were female, with a mean age of 39.3 ± 11.3 years. The body mass index was significant at the 6th month: 39.1 ± 6.7 and 30.3 ± 4.7 kg/m² (P < 0.001), respectively. The mean preoperative controlled attenuation parameter and liver stiffness measurement values were 325.4 ± 55.9 dB/m and 7.4 ± 4.8 kPa, respectively, before surgery, and they decreased to 267.1 ± 45.1 dB/m and 5.3 ± 2.3 kPa, respectively, 6 months postoperatively (P < 0.001, respectively).

Conclusion

These results suggest that bariatric surgery is associated with a significant improvement in liver steatosis and fibrosis. Bariatric surgery has a beneficial effect on nonalcoholic fatty liver disease in patients with morbid obesity in Korea.

Increased Hepatic Fat Content in Patients with Resistance to Thyroid Hormone Beta

Background: Thyroid hormone (TH) has important functions in controlling hepatic lipid metabolism. Individuals with resistance to thyroid hormone beta (RTHβ) who harbor mutations in the THRB gene experience loss-of-function of thyroid hormone receptor beta (TRβ), which is the predominant TR isoform expressed in the liver. We hypothesized that individuals with RTHβ may have increased hepatic steatosis. Methods: Controlled attenuation parameter (CAP) was assessed in individuals harboring the R243Q mutation of the THRB gene (n = 21) and in their wild-type (WT) first-degree relatives (n = 22) using the ultrasound-based transient elastography (TE) device (FibroScan). All participants belonged to the same family, lived on the same small island, and were therefore exposed to similar environmental conditions. CAP measurements and blood samples were obtained after an overnight fast. The observers were blinded to the status of the patients. Results: The hepatic fat content was increased in RTHβ individuals compared with their WT relatives (CAP values of 263 ± 21 and 218.7 ± 43 dB/m, respectively, p = 0.007). The CAP values correlated with age and body mass index (BMI) (age: r = 0.55, p = 0.011; BMI: r = 0.51, p = 0.022) in the WT first-degree relatives but not in RTHβ individuals, suggesting that the defect in TRβ signaling was predominant over the effects of age and obesity. Circulating free fatty acid levels were significantly higher in RTHβ individuals (0.29 ± 0.033 vs. 0.17 ± 0.025 mmol/L, p = 0.02). There was no evidence of insulin resistance evaluated by the homeostatic model assessment of insulin resistance in both groups studied. Conclusions: Our findings provide evidence that impairments in intrahepatic TRβ signaling due to mutations of the THRB gene can lead to hepatic steatosis, which emphasizes the influence of TH in the liver metabolism of lipids and provides a rationale for the development TRβ-selective thyromimetics. Consequently, new molecules with a very high TRβ affinity and hepatic selectivity have been developed for the treatment of lipid-associated hepatic disorders, particularly nonalcoholic fatty liver disease.

Noninvasive Assessment of Hepatitis C Virus Infected Patients Using Vibration-Controlled Transient Elastography

Chronic infection with hepatitis C virus (HCV) is one of the leading causes of cirrhosis and hepatocellular carcinoma (HCC). Surveillance of these patients is an essential strategy in the prevention chain, including in the pre/post-antiviral treatment states. Ultrasound elastography techniques are emerging as key methods in the assessment of liver diseases, with a number of advantages such as their rapid, noninvasive, and cost-effective characters. The present paper critically reviews the performance of vibration-controlled transient elastography (VCTE) in the assessment of HCV patients. VCTE measures liver stiffness (LS) and the ultrasonic attenuation through the embedded controlled attenuation parameter (CAP), providing the clinician with a tool for assessing fibrosis, cirrhosis, and steatosis in a noninvasive manner. Moreover, standardized LS values enable proper staging of the underlying fibrosis, leading to an accurate identification of a subset of HCV patients that present a high risk for complications. In addition, VCTE is a valuable technique in evaluating liver fibrosis prior to HCV therapy. However, its applicability in monitoring fibrosis regression after HCV eradication is currently limited and further studies should focus on extending the boundaries of VCTE in this context. From a different perspective, VCTE may be effective in identifying clinically significant portal hypertension (CSPH). An emerging prospect of clinical significance that warrants further study is the identification of esophageal varices. Our opinion is that the advantages of VCTE currently outweigh those of other surveillance methods.

Validating controlled attenuation parameter in the assessment of hepatic steatosis in living liver donors

INTRODUCTION

Hepatic steatosis (HS) negatively impacts transplant outcomes in living liver donors. To date, liver biopsy is preferred for HS evaluation. This study aims to evaluate the measurement of controlled attenuation parameter (CAP) as a diagnostic tool of HS in living liver donors.

METHODS

Candidates recruited to this study, conducted from April 2016 to February 2020, were potential donors who had undergone transient elastography using Fibroscan® and CAP measurements at liver segments VI and VII, followed by liver biopsy. The HS grades from liver biopsy were classified as S0 (<5%), S1 (5-33%), S2 (33-66%), and S3 (>66%). For CAP, they were S0 (≤218dB/m), S1 (218-249dB/m)), S2 (250-305dB/m)), and S3 (>305dB/m)). The CAP measurements were compared with the liver biopsy results.

RESULTS

Of the 150 potential donors [male, 73.3%; mean age, 30.0±7.0 years; body mass index (BMI), 24.7±3.5kg/m2], 92 (61.3%) had no or mild HS, while 58 (38.7%) and 10% had moderate to severe HS based on CAP and liver biopsy, respectively. Subjects with moderate to severe HS per CAP were mostly males (0.014), and had higher BMI (p = .006), alanine aminotransferase (ALT) (.001), gamma-glutamyl transferase (.026), and high-density lipoprotein (.008). On multivariate analysis, high ALT (OR, 1.051; 95% CI, 1.016-1.087; p = .004) was a predictor of significant HS. The sensitivity, specificity, positive and negative predictive values of CAP to detect significant HS were 93.3%, 67.4, 24.1%, and 98.9%, respectively.

CONCLUSION

The high sensitivity and negative predictive values of CAP make it a good screening test to exclude significant HS in potential living liver donors which, in turn, can help avoid unnecessary liver biopsies.

Correlation of the grade of hepatic steatosis between controlled attenuation parameter and ultrasound in patients with fatty liver: a multi-center retrospective cohort study

BACKGROUND/AIMS

The controlled attenuation parameter (CAP), based on transient elastography, is widely used for noninvasive assessment of the degree of hepatic steatosis (HS). We investigated the correlation of the degree HS between CAP and ultrasound (US) in patients with HS.

METHODS

In total, 986 patients with US-based HS who underwent transient elastography within 1 month were evaluated. The US-based grade of HS was categorized as mild (grade 1), moderate (grade 2), or severe (grade 3).

RESULTS

The CAP was significantly correlated with the US-based grade of HS (r = 0.458, p < 0.001). The median CAP value of each US-based HS grade showed a positive correlation with grade (271.1, 303.7, and 326.7 dB/m for grades 1, 2, and 3). In a multivariate analysis, the US-based HS grade, body mass index, serum albumin, alanine aminotransferase, and total cholesterol, and liver stiffness were all significantly correlated with the CAP value (all p < 0.05). The areas under the receiver operating characteristic curves for grade 2 to 3 and grade 3 HS were 0.749 (95% confidence interval [CI], 0.714 to 0.784) and 0.738 (95% CI, 0.704 to 0.772). The optimal cut-off CAP values to maximize the sum of the sensitivity and specificity for grade 2 to 3 and grade 3 HS were 284.5 dB/m (sensitivity 78.6%, specificity 61.7%) and 298.5 dB/m (sensitivity 84.6%, specificity 55.6%).

CONCLUSION

The correlation of the degree of HS between CAP and US was significantly high in patients with HS, and the optimal cut-off CAP values for grade 2 to 3 and grade 3 HS were 284.5 and 298.5 dB/m.

Discrimination of Nonalcoholic Steatohepatitis Using Transient Elastography in Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND/AIMS

The accuracy of noninvasive markers to discriminate nonalcoholic steatohepatitis (NASH) is unsatisfactory. We investigated whether transient elastography (TE) could discriminate patients with NASH from those with nonalcoholic fatty liver disease (NAFLD).

METHODS

The patients suspected of NAFLD who underwent liver biopsy and concomitant TE were recruited from five tertiary centers between November 2011 and December 2013.

RESULTS

The study population (n = 183) exhibited a mean age of 40.6 years and male predominance (n = 111, 60.7%). Of the study participants, 89 (48.6%) had non-NASH and 94 (51.4%) had NASH. The controlled attenuation parameter (CAP) and liver stiffness (LS) were significantly correlated with the degrees of steatosis (r = 0.656, P<0.001) and fibrosis (r = 0.714, P<0.001), respectively. The optimal cut-off values for steatosis were 247 dB/m for S1, 280 dB/m for S2, and 300 dB/m for S3. Based on the independent predictors derived from multivariate analysis [P = 0.044, odds ratio (OR) 4.133, 95% confidence interval (CI) 1.037-16.470 for CAP>250 dB/m; P = 0.013, OR 3.399, 95% CI 1.295-8.291 for LS>7.0 kPa; and P<0.001, OR 7.557, 95% CI 2.997-19.059 for Alanine aminotransferase>60 IU/L], we developed a novel CLA model for discriminating patients with NASH. The CLA model showed good discriminatory capability, with an area under the receiver operating characteristic curve (AUROC) of 0.812 (95% CI 0.724-0.880). To assess discriminatory power, the AUROCs, as determined by the bootstrap method, remained largely unchanged between iterations, with an average value of 0.833 (95% CI 0.740-0.893).

CONCLUSION

This novel TE-based CLA model showed acceptable accuracy in discriminating NASH from simple steatosis. However, further studies are required for external validation.

Comparison of Controlled Attenuation Parameter and Liver Biopsy to Assess Hepatic Steatosis in Pediatric Patients

OBJECTIVE

To assess whether the degree of steatosis as determined by controlled attenuation parameter (CAP) measurements correlates with that observed on liver biopsies in a single-center pediatric and young adult cohort.

STUDY DESIGN

This cross-sectional study included patients undergoing liver biopsy as part of standard clinical care between January 25, 2012, and April 1, 2015, at Boston Children's Hospital. Eligible patients, with a variety of liver diseases, had CAP measurements within 1 year of biopsy. CAP values were compared across histologic steatosis grades using ANOVA.

RESULTS

Sixty-nine patients (mean age, 16.0 ± 2.9 years; 62% male) were studied. CAP measurements were obtained at a median of 1.3 months (IQR, 0.5-3.2) after biopsy. Of the 69 subjects, 23 had steatosis on biopsy. Mean CAP value (dB/m) for subjects with no steatosis was 198 ± 37 vs 290 ± 47 for subjects with steatosis (P < .0001). There were statistically significant differences between CAP values in individuals with no steatosis vs mild/moderate steatosis (P < .0001), no steatosis vs marked steatosis (P < .0001), and mild/moderate vs marked steatosis (P = .004).

CONCLUSION

This study demonstrated a difference in CAP between no steatosis and steatosis, and between grades of steatosis. CAP may be a useful noninvasive tool to detect hepatic steatosis in children.

Noninvasive Prediction of Erosive Esophagitis Using a Controlled Attenuation Parameter (CAP)-Based Risk Estimation Model

BACKGROUND

Erosive esophagitis and fatty liver share obesity and visceral fat as common critical pathogenesis. However, the relationship between the amount of hepatic fat and the severity of erosive esophagitis was not well investigated, and there is no risk estimation model for erosive esophagitis.

AIM

To evaluate the relationship between the amount of hepatic fat and the severity of erosive esophagitis and then develop a risk estimation model for erosive esophagitis.

METHODS

We enrolled 1045 consecutive participants (training cohort, n = 705; validation cohort, n = 340) who underwent esophagogastroduodenoscopy and CAP. The relationship between severity of fatty liver and erosive esophagitis was investigated, and independent predictors for erosive esophagitis that have been investigated through logistic regression analyses were used as components for establishing a risk estimation model.

RESULTS

The prevalence of erosive gastritis was 10.7 %, and the severity of erosive esophagitis was positively correlated with the degree of hepatic fatty accumulation (P < 0.05). A CAP-based risk estimation model for erosive esophagitis using CAP, Body mass index, and significant alcohol Drinking as constituent variables was established and was dubbed the CBD score (AUROC = 0.819, range 0-11). The high-risk group (CBD score ≥3) showed significantly higher risk of having erosive esophagitis than the low-risk group (CBD score <3) (24.1 vs. 2.7 %, respectively; P < 0.001). The diagnostic accuracy of CBD score was maintained in the validation cohort (AUROC = 0.848).

CONCLUSION

The severity of erosive esophagitis was positively correlated with the degree of hepatic fatty accumulation, and the CBD score might be a simple CAP-based risk model for predicting erosive esophagitis.