[Transient elastography for diagnosing liver cirrhosis]

Transient Elastography for the Detection of Liver Damage in Patients with HIV

Introduction

Highly active antiretroviral therapy (HAART) is effective and well tolerated, but hepatotoxicity is relatively common. Different non-invasive methods are available for detecting liver fibrosis in patients with chronic liver disease.

Methods

Patients who were HIV positive and who had given their informed consent were included in this cross-sectional study. Transient elastography [FibroScan^® (FS); Echosens], serum hyaluronic acid (HA), Hepascore (HS), Fibrosis-4 (FIB-4), and aspartate aminotransferase to platelet ratio index (APRI) were used to detect liver fibrosis in the patients. The agreement between FS and the other methods was evaluated. To observe the hepatotoxicity of HAART, patients with chronic viral hepatitis B or C were excluded by detection of hepatitis B surface antigens and hepatitis C virus antibodies. Patients with chronic alcohol intake were excluded by measuring carbohydrate-deficient transferrin (CDT). FS correlation with the duration of therapy with protease inhibitors (PI), nucleoside reverse transcriptase inhibitors (NRTI), and non-nucleoside reverse transcriptase inhibitors (NNRTI) was evaluated.

Results

Overall, 203 patients were included in the study. The agreement between the different tests ranged from 64% to 77%: FS vs. HA, 72%; FS vs. APRI, 74%; FS vs. HS, 77%; and FS vs. FIB-4, 64%. After excluding patients with chronic hepatitis B or C and elevated CDT, 153 patients remained for studying the hepatotoxicity of HAART. A significant correlation of FS with the duration of medication intake was observed for PIs (P = 0.026; r = 0.18). NRTI and NNRTI therapy duration did not correlate with FS.

Conclusions

The agreement between FS and other tests ranged from 64% to 77%. A significant correlation was found between liver stiffness and the duration of therapy with PIs, which underlines the known hepatotoxicity of this substance group.

Funding

Heinz-Ansmann Foundation.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-015-0073-y) contains supplementary material, which is available to authorized users.

Evaluation of Acoustic Radiation Force Impulse Imaging (ARFI) for the Determination of Liver Stiffness Using Transient Elastography as a Reference in Children

PURPOSE

Transient elastography (Fibroscan(©); (FS)) and acoustic radiation force impulse imaging (ARFI) represent noninvasive, user-friendly and quick methods providing an objective and reproducible measure of liver stiffness. The aim of the study was to evaluate cut-off values and performance of ARFI measurements in children using transient elastography as a reference.

METHODS/PATIENTS

A total of 198 children were enrolled in this study. All patients underwent liver stiffness measurements with FS (FS-LS) as well as ARFI (with shear wave velocity quantification; ARFI-SWV) and the performance of ARFI in comparison to FS was studied.

RESULTS

Significantly higher rates of successful measurements were found for ARFI compared to FS (198/198 (100%) vs. 160/198 (80.8%); p<0.001). ARFI-SWV correlated significantly with FS-LS (r=0.751, p=0.001). ARFI-SWV increased significantly with the stage of fibrosis (1.19+0.15 m/s for patients with FS-LS<7.6 kPa); 1.34+0.22 m/s for patients with 7.613.0 kPa). ARFI-SWV cut-off values were identified for no significant fibrosis (1.31 m/s; sensitivity 61.8% and specificity 79.5%) and for liver cirrhosis (1.63 m/s; sensitivity 70.0% and specificity 97.4%). The median values of liver stiffness measured by FS were age-dependent in 90 children without liver diseases with 4.8, 5.6, and 5.7 kPa in children 0-5, 6-11, and 12-18 years, respectively.

Transient elastography improves detection of liver cirrhosis compared to routine screening tests

AIM: To investigate the diagnostic significance of transient elastography (TE) in a daily routine clinical setting in comparison to clinical signs, laboratory parameters and ultrasound.

METHODS: TE, ultrasound, laboratory parameters and cutaneous liver signs were assessed in 291 consecutive patients with chronic liver disease of various aetiologies who underwent liver biopsy in daily routine.

RESULTS: Sensitivity of TE for the detection of liver cirrhosis was 90.4%, compared to 80.1% for ultrasound, 58.0% for platelet count and 45.1% for cutaneous liver signs (P < 0.0001 for comparisons with histology). AUROC for TE was 0.760 (95%CI: 0.694-0.825). Combination of TE with ultrasound increased sensitivity to 96.1% and AUROC to 0.825 (95%CI: 0.768-0.882). TE correlated with laboratory parameters of cirrhosis progression like albumin (r = -0.43), prothrombin time (r = -0.44), and bilirubin (r = 0.34; P < 0.001 for each). Particularly, in patients with Child Pugh score A or normal platelet count TE improved sensitivity for the detection of liver cirrhosis compared to ultrasound by 14.1% (P < 0.04) and 16.3% (P < 0.02), respectively.

CONCLUSION: Transient elastography is superior to routine diagnostic tests allowing detection of liver cirrhosis in additional 10%-16% of patients with chronic liver disease that would have been missed by clinical examinations.

A novel mutation within a transmembrane helix of the bile salt export pump (BSEP, ABCB11) with delayed development of cirrhosis

BACKGROUND & AIMS

The bile salt export pump (BSEP, ABCB11) is essential for bile salt secretion at the canalicular membrane of liver cells. Clinical phenotypes associated with BSEP mutations are commonly categorized as benign recurrent intrahepatic cholestasis (BRIC-2) or progressive familial intrahepatic cholestasis (PFIC-2).

METHODS

The molecular basis of BSEP-associated liver disease in a sibling pair was characterized by immunostaining, gene sequencing, bile salt analysis and recombinant expression in mammalian cells and yeast for localization and in vitro activity studies respectively.

RESULTS

Benign recurrent intrahepatic cholestasis was considered in a brother and sister who both suffered from intermittent cholestasis since childhood. Gene sequencing of ABCB11 identified the novel missense mutation p.G374S, which is localized in the putative sixth transmembrane helix of BSEP. Liver fibrosis was present in the brother at the age of 18 with progression to cirrhosis within 3 years. Immunofluorescence of liver tissue showed clear canalicular BSEP expression; however, biliary concentration of bile salts was drastically reduced. In line with these in vivo findings, HEK293 cells showed regular membrane targeting of human BSEP(G374S), whereas in vitro transport measurements revealed a strongly reduced transport activity.

CONCLUSIONS

The novel mutation p.G374S impairs transport function without disabling membrane localization of BSEP. While all other known BSEP mutations within transmembrane helices are associated with PFIC-2, the new p.G374S mutation causes a transitional phenotype between BRIC-2 and PFIC-2.

Role of fibroscan and APRI in detection of liver fibrosis: a systematic review and meta-analysis

BACKGROUND AND STUDY AIMS

Fibroscan and APRI are promising noninvasive alternatives to liver biopsy for detecting hepatic fibrosis. However, their overall test performance in various settings remains questionable. The aim of our study was to perform a systematic review and meta-analysis of diagnostic accuracy studies comparing fibroscan and APRI with liver biopsy for hepatic fibrosis.

PATIENTS AND METHODS

Electronic and manual bibliographic searches to identify potential studies were performed. Selection of studies was based on reported accuracy of fibroscan and APRI compared with liver biopsy. Data extraction was performed independently by two reviewers. Meta-analysis combined the sensitivities, specificities, and likelihood ratios of individual studies. Extent and reasons for heterogeneity were assessed.

RESULTS

23 studies for fibroscan and 20 studies for APRI in full publication were identified. For patients with stage IV fibrosis (cirrhosis), the pooled estimates for sensitivity of fibroscan were 83.4% (95% confidence interval [CI], 71.7-95.0%) and specificity 92.4% (95% CI, 85.6-99.2%). For patients with stage IV fibrosis (cirrhosis), the pooled estimates for sensitivity of APRI at cutoff point of 1.5 were 66.5% (95% CI, 25.0-100%) and specificity 71.7% (95% CI, 35.0-100%). Diagnostic threshold bias was identified as an important cause of heterogeneity for pooled results in both patient groups.

CONCLUSIONS

Fibroscan and APRI appear to be clinically useful tests for detecting cirrhosis however not useful tools in early stages of fibrosis.

The effect of hemodialysis on liver stiffness measurement: a single-center series

BACKGROUND/AIMS

The noninvasive measurement of liver stiffness using transient elastography (TE) is increasingly being used alongside liver biopsy. However, several conditions may lead to higher liver stiffness values without reflecting more fibrosis. Such conditions (e.g. hepatitis, cholestasis, heart failure, mechanical ventilation) limit the interpretation of liver stiffness measurements. The influence of hemodialysis on the measurement of liver stiffness has not been investigated to date. Here, we analyzed liver stiffness assessed by fibroscan in 17 patients directly before and after a hemodialysis session.

PATIENTS AND METHODS

Measurement of hepatic stiffness by TE was carried out using the Fibroscan device with the 'M probe' directly before and directly after one session of hemodialysis. Each measurement consisted of at least 10 individual and valid measurements, with a success rate of at least 60%, and an interquartile range of less than 25%. All measurements were carried out by one investigator not involved in patient management.

RESULTS

Before dialysis, the median TE was 5.1 kPa (2.8-17 kPa). Ten patients had values below the threshold of 7.1 kPa and seven patients had TE>7.1 kPa. The median net fluid withdrawal by hemodialysis was 2.5 l (0.4-3.1 l) and did not differ between patients. After dialysis, the TE median was 7.4 kPa (3.5-12.5 kPa) and had changed in all patients except one. Liver stiffness increased significantly when the initial TE was lower than 7.1 kPa (P=0.05), but not when the initial TE was higher than 7.1 kPa. Furthermore, the magnitude of the change in TE after hemodialysis correlated inversely with the liver stiffness before hemodialysis (P=0.03) and with spleen length measured by ultrasound (P=0.03).

CONCLUSION

This study is the first to report on the influence of hemodialysis on liver stiffness measurement. In contrast to previous reports, liver stiffness might increase after fluid withdrawal if patients do not show significant fibrosis. We conclude that before dialysis, TE possibly better differentiates between patients with or without significant fibrosis.

Non-invasive assessment of hepatic fibrosis in a series of patients with Wilson's Disease

BACKGROUND/AIMS

Liver biopsy has always represented the standard of reference in hepatic fibrosis assessment. Recently, blood markers and instrumental methods have been proposed for non-invasive assessment. The aim of this study was to validate transient elastography and other non-invasive tests compared to liver histology in Wilson's Disease.

METHODS

Liver stiffness in 35 Wilson's Disease patients was evaluated by Fibroscan, serum fibrosis markers (AST-to-platelet-ratio index and FIB-4) and biopsy.

RESULTS

Compared to liver histology, the FibroScan values increased proportionally with progression of the histological fibrosis stage. Significant fibrosis could be predicted with a Fibroscan cut-off value of 6.6 kPa. Advanced fibrosis could be predicted with a FibroScan cut-off value of 8.4 kPa. Serum fibrosis marker values gave good correlation with hepatic stage.

CONCLUSIONS

A FibroScan value of 6.6 kPa was found to be a significant separation limit for differentiating significant fibrosis stages from milder stages and a fibroscan value of 8.4 kPa was found to be a significant separation limit for differentiating advanced fibrosis stages from milder stages. FibroScan values are clinically useful for predicting fibrosis stages and helpful in managing chronic therapy in Wilson's Disease patients.

Evaluation of acoustic radiation force impulse imaging for determination of liver stiffness using transient elastography as a reference

AIM: To evaluate cut-off values and performance of acoustic radiation force impulse imaging (ARFI) using transient elastography [FibroScan^© (FS)] as a reference.

METHODS: Six hundred and six patients were enrolled in this study. All patients underwent liver stiffness measurement with FS (FS-LS) and ARFI (with shear wave velocity quantification; ARFI-SWV) and the performance of ARFI in comparison to FS was determined. Sixty-eight patients underwent liver biopsy.

RESULTS: Significantly higher success rates for the determination of liver stiffness were found using ARFI as compared to FS [604/606 (99.7%) vs 482/606 (79.5%), P < 0.001]. ARFI-SWV correlated significantly with FS-LS (r = 0.920, P < 0.001). ARFI-SWV increased significantly with the stage of fibrosis (1.09 ± 0.13 m/s for patients with no significant fibrosis (FS-LS < 7.6 kPa); 1.46 ± 0.27 m/s for patients with significant liver fibrosis (7.6 < FS-LS ≤ 13.0 kPa); and 2.55 ± 0.77 m/s for patients with liver cirrhosis (FS-LS > 13.0 kPa)). ARFI-SWV cut-off values were identified for no significant fibrosis (1.29 m/s; sensitivity 91.4% and specificity 92.6%) and for liver cirrhosis (1.60 m/s; sensitivity 92.3% and specificity 96.5%). The optimal cut-off value for predicting liver fibrosis (F ≥ 2) was 1.32 m/s (sensitivity 87.0% and specificity 80.0%) and for liver cirrhosis (F4) 1.62 m/s (sensitivity 100% and specificity 85.7%), for patients who underwent liver biopsy. An excellent inter-and intraobserver reproducibility was observed for ARFI-SWV determinations.

CONCLUSION: An ARFI-SWV cut-off value of 1.29 m/s seems to be optimal for patients with no significant liver fibrosis and 1.60 m/s for patients with liver cirrhosis.

Liver fibrosis in recessive multicystic kidney diseases: transient elastography for early detection

Cystic renal diseases are characterized by intrarenal cysts of different size and number. Further important diagnostic criteria include, e.g., liver fibrosis. The latter represents a significant cause of morbidity and mortality in autosomal-recessive polycystic kidney disease (ARPKD), whereas patients with autosomal-dominant polycystic kidney disease (ADPKD) can develop hepatic cysts without fibrosis. We report the use of transient elastography [FibroScan®, (FS)] for early and noninvasive detection of increased liver stiffness as marker of liver fibrosis. Compared with matched healthy controls, ADPKD patients (n = 7) showed no significant difference in liver stiffness (5.3 kPa vs. 4.5 kPa; ns). ARPKD patients (n = 7) had significantly increased median liver stiffness compared with controls (12.0 kPa vs. 4.5 kPa, p = 0.002) and ADPKD patients (12.0 kPa vs. 5.3 kPa, p = 0.002). Conventional ultrasound revealed evidence of liver fibrosis in only four of seven ARPKD patients (57%) compared with 100% detection by FS. Additional laboratory examinations showed no pathologic liver parameters. In conclusion, our data found FS to be a valuable, sensitive, and noninvasive new tool for early evaluation of liver fibrosis in cystic kidney diseases. This could facilitate diagnosis, monitoring, and management of liver involvement in ARPKD or any other cystic kidney disease.

Transient micro-elastography: A novel non-invasive approach to measure liver stiffness in mice

AIM: To develop and validate a transient micro-elastography device to measure liver stiffness (LS) in mice.

METHODS: A novel transient micro-elastography (TME) device, dedicated to LS measurements in mice with a range of measurement from 1-170 kPa, was developed using an optimized vibration frequency of 300 Hz and a 2 mm piston. The novel probe was validated in a classical fibrosis model (CCl₄) and in a transgenic murine model of systemic amyloidosis.

RESULTS: TME could be successfully performed in control mice below the xiphoid cartilage, with a mean LS of 4.4 ± 1.3 kPa, a mean success rate of 88%, and an excellent intra-observer agreement (0.98). Treatment with CCl₄ over seven weeks drastically increased LS as compared to controls (18.2 ± 3.7 kPa vs 3.6 ± 1.2 kPa). Moreover, fibrosis stage was highly correlated with LS (Spearman coefficient = 0.88, P < 0.01). In the amyloidosis model, much higher LS values were obtained, reaching maximum values of > 150 kPa. LS significantly correlated with the amyloidosis index (0.93, P < 0.0001) and the plasma concentration of mutant hapoA-II (0.62, P < 0.005).

CONCLUSION: Here, we have established the first non-invasive approach to measure LS in mice, and have successfully validated it in two murine models of high LS.

Liver stiffness: a novel parameter for the diagnosis of liver disease

The noninvasive quantitation of liver stiffness (LS) by ultrasound based transient elastography using FibroScan® has revolutionized the diagnosis of liver diseases, namely liver cirrhosis. Alternative techniques such as acoustic radiation impulse frequency imaging or magnetic resonance elastography are currently under investigation. LS is an excellent surrogate marker of advanced fibrosis (F3) and cirrhosis (F4) outscoring all previous noninvasive approaches to detect cirrhosis. LS values below 6 kPa are considered as normal and exclude ongoing liver disease. LS of 8 and 12.5 kPa represent generally accepted cut-off values for F3 and F4 fibrosis. LS highly correlates with portal pressure, and esophageal varices are likely at values >20 kPa. Many other factors may also increase LS such as hepatic infiltration with tumor cells, mast cells (mastocytosis), inflammatory cells (all forms of hepatitis) or amyloidosis. In addition, LS is directly correlated with the venous pressure (eg, during liver congestion) and is increased during mechanic cholestasis. Thus, LS should always be interpreted in the context of clinical, imaging and laboratory findings. Finally, LS has helped to better understand the molecular mechanisms underlying liver fibrosis. The novel pressure-stiffness-fibrosis sequence hypothesis is introduced.

Increased liver stiffness in alcoholic liver disease: differentiating fibrosis from steatohepatitis

AIM

To test if inflammation also interferes with liver stiffness (LS) assessment in alcoholic liver disease (ALD) and to provide a clinical algorithm for reliable fibrosis assessment in ALD by FibroScan (FS).

METHODS

We first performed sequential LS analysis before and after normalization of serum transaminases in a learning cohort of 50 patients with ALD admitted for alcohol detoxification. LS decreased in almost all patients within a mean observation interval of 5.3 d. Six patients (12%) would have been misdiagnosed with F3 and F4 fibrosis but LS decreased below critical cut-off values of 8 and 12.5 kPa after normalization of transaminases.

RESULTS

Of the serum transaminases, the decrease in LS correlated best with the decrease in glutamic oxaloacetic transaminase (GOT). No significant changes in LS were observed below GOT levels of 100 U/L. After establishing the association between LS and GOT levels, we applied the rule of GOT < 100 U/L for reliable LS assessment in a second validation cohort of 101 patients with histologically confirmed ALD. By excluding those patients with GOT > 100 U/L at the time of LS assessment from this cohort, the area under the receiver operating characteristic (AUROC) for cirrhosis detection by FS improved from 0.921 to 0.945 while specificity increased from 80% to 90% at a sensitivity of 96%. A similar AUROC could be obtained for lower F3 fibrosis stage if LS measurements were restricted to patients with GOT < 50 U/L. Histological grading of inflammation did not further improve the diagnostic accuracy of LS.

CONCLUSION

Coexisting steatohepatitis markedly increases LS in patients with ALD independent of fibrosis stage. Postponing cirrhosis assessment by FS during alcohol withdrawal until GOT decreases to < 100 U/mL significantly improves the diagnostic accuracy.

Increased liver stiffness in alcoholic liver disease: Differentiating fibrosis from steatohepatitis

AIM: To test if inflammation also interferes with liver stiffness (LS) assessment in alcoholic liver disease (ALD) and to provide a clinical algorithm for reliable fibrosis assessment in ALD by FibroScan^® (FS).

METHODS: We first performed sequential LS analysis before and after normalization of serum transaminases in a learning cohort of 50 patients with ALD admitted for alcohol detoxification. LS decreased in almost all patients within a mean observation interval of 5.3 d. Six patients (12%) would have been misdiagnosed with F3 and F4 fibrosis but LS decreased below critical cut-off values of 8 and 12.5 kPa after normalization of transaminases.

RESULTS: Of the serum transaminases, the decrease in LS correlated best with the decrease in glutamic oxaloacetic transaminase (GOT). No significant changes in LS were observed below GOT levels of 100 U/L. After establishing the association between LS and GOT levels, we applied the rule of GOT < 100 U/L for reliable LS assessment in a second validation cohort of 101 patients with histologically confirmed ALD. By excluding those patients with GOT > 100 U/L at the time of LS assessment from this cohort, the area under the receiver operating characteristic (AUROC) for cirrhosis detection by FS improved from 0.921 to 0.945 while specificity increased from 80% to 90% at a sensitivity of 96%. A similar AUROC could be obtained for lower F3 fibrosis stage if LS measurements were restricted to patients with GOT < 50 U/L. Histological grading of inflammation did not further improve the diagnostic accuracy of LS.

CONCLUSION: Coexisting steatohepatitis markedly increases LS in patients with ALD independent of fibrosis stage. Postponing cirrhosis assessment by FS during alcohol withdrawal until GOT decreases to < 100 U/mL significantly improves the diagnostic accuracy.

Liver stiffness is directly influenced by central venous pressure

BACKGROUND & AIMS

Liver stiffness (LS) as measured by transient elastography [Fibroscan] offers a novel non-invasive approach to assess liver cirrhosis. Since Fibroscan seems to be unreliable in patients with congestive heart failure, it remains to be determined whether hemodynamic changes affect LS irrespective of fibrosis.

METHODS & RESULTS

Using landrace pigs, we studied the direct relationship between the central venous pressure and LS measured by Fibroscan. Clamping of the inferior caval vein increased LS from 3.1 to 27.8kPa while reopening reversed LS within 5min to almost normal values of 5.1kPa. We then studied LS as a function of venous pressure in the isolated pig liver by clamping the upper and lower caval, portal vein and hepatic artery. The stepwise increase of intravenous pressure to 36cm of water column (3.5kPa) linearly and reversibly increased LS to the upper detection limit of 75kPa. We finally measured LS in 10 patients with decompensated congestive heart failure before and after recompensation. Initial LS was elevated in all patients, in 8 of them to a degree that suggested liver cirrhosis (median 40.7kPa). Upon recompensation with a median weight loss of 3.0kg, LS decreased in all 10 patients down to a median LS of 17.8kPa. Inflammation could not account for increased LS since initial liver enzyme counts were only slightly elevated and did not change significantly.

CONCLUSION

LS is a direct function of central venous pressure which should be considered when assessing the degree of fibrosis.

Assessment of liver fibrosis: noninvasive means

Liver biopsy, owing to its limitations and risks, is an imperfect gold standard for assessing the severity of the most frequent chronic liver diseases chronic hepatitis C (HCV), B (HBV) non alcoholic (NAFLD) and alcoholic (ALD) fatty liver diseases. This review summarizes the advantages and the limits of the available biomarkers of liver fibrosis. Among a total of 2,237 references, a total of 14 validated serum biomarkers have been identified between 1991 and 2008. Nine were not patented and five were patented. Two alternatives to liver biopsy were the most evaluated FibroTest and Fibroscan. For FibroTest, there was a total of 38 different populations including 7,985 subjects with both FibroTest and biopsy (4,600 HCV, 1,580 HBV, 267 NAFLD, 524 ALD, and 1014 mixed). For Fibroscan, there was a total of 11 published studies including 2,260 subjects (1,466 HCV, 95 cholestatic liver disease, and 699 mixed). For FibroTest, the mean diagnostic value for the diagnosis of advanced fibrosis assessed using standardized area under the ROC curves was 0.84 (95% confidence interval 0.83-0.86), without a significant difference between the causes of liver disease, hepatitis C, hepatitis B, and alcoholic or non alcoholic fatty liver disease. High-risk profiles of false negative/false positive of FibroTest, mainly Gilbert syndrome, hemolysis and acute inflammation, are present in 3% of the populations. In case of discordance between biopsy and FibroTest, half of the failures can be due to biopsy; the prognostic value of FibroTest is at least similar to that of biopsy in HCV, HBV and ALD. In conclusion this overview of evidence-based data suggests that biomarkers could be used as an alternative to liver biopsy for the first line assessment of fibrosis stage in the four most common chronic liver diseases, namely HCV, HBV, NAFLD and ALD. Neither biomarkers nor biopsy alone is sufficient for taking a definite decision in a given patient; all the clinical and biological data must be taken into account. There is no evidence based data justifying biopsy as a first line estimate of liver fibrosis. Health authorities in some countries have already approved validated biomarkers as the first line procedure for the staging of liver fibrosis.

Extrahepatic cholestasis increases liver stiffness (FibroScan) irrespective of fibrosis

Transient elastography (FibroScan [FS]) is a novel non-invasive tool to assess liver fibrosis/cirrhosis. However, it remains to be determined if other liver diseases such as extrahepatic cholestasis interfere with fibrosis assessment because liver stiffness is indirectly measured by the propagation velocity of an ultrasound wave within the liver. In this study, we measured liver stiffness immediately before endoscopic retrograde cholangiopancreatography and 3 to 12 days after successful biliary drainage in patients with extrahepatic cholestasis mostly due to neoplastic invasion of the biliary tree. Initially elevated liver stiffness decreased in 13 of 15 patients after intervention, in 10 of them markedly. In three patients, liver stiffness was elevated to a degree that suggested advanced liver cirrhosis (mean, 15.2 kPa). Successful drainage led to a drop of bilirubin by 2.8 to 9.8 mg/dL whereas liver stiffness almost normalized (mean, 7.1 kPa). In all patients with successful biliary drainage, the decrease of liver stiffness highly correlated with decreasing bilirubin (Spearman's rho = 0.67, P < 0.05) with a mean decrease of liver stiffness of 1.2 +/- 0.56 kPa per 1 g/dL bilirubin. Two patients, in whom liver stiffness did not decrease despite successful biliary drainage, had advanced liver cirrhosis and multiple liver metastases, respectively. The relationship between extrahepatic cholestasis and liver stiffness was reproduced in an animal model of bile duct ligation in landrace pigs where liver stiffness increased from 4.6 kPa to 8.8 kPa during 120 minutes of bile duct ligation and decreased to 6.1 kPa within 30 minutes after decompression.

CONCLUSION

Extrahepatic cholestasis increases liver stiffness irrespective of fibrosis. Once extrahepatic cholestasis is excluded (e.g., by liver imaging and laboratory parameters) transient elastography is a valuable tool to assess liver fibrosis in chronic liver diseases.

Assessment of liver fibrosis: noninvasive means

Liver biopsy, owing to its limitations and risks, is an imperfect gold standard for assessing the severity of the most frequent chronic liver diseases chronic hepatitis C (HCV), B (HBV) non alcoholic (NAFLD) and alcoholic (ALD) fatty liver diseases. This review summarizes the advantages and the limits of the available biomarkers of liver fibrosis. Among a total of 2,237 references, a total of 14 validated serum biomarkers have been identified between 1991 and 2008. Nine were not patented and five were patented. Two alternatives to liver biopsy were the most evaluated FibroTest and Fibroscan. For FibroTest, there was a total of 38 different populations including 7,985 subjects with both FibroTest and biopsy (4,600 HCV, 1,580 HBV, 267 NAFLD, 524 ALD, and 1014 mixed). For Fibroscan, there was a total of 11 published studies including 2,260 subjects (1,466 HCV, 95 cholestatic liver disease, and 699 mixed). For FibroTest, the mean diagnostic value for the diagnosis of advanced fibrosis assessed using standardized area under the ROC curves was 0.84 (95% confidence interval 0.83-0.86), without a significant difference between the causes of liver disease, hepatitis C, hepatitis B, and alcoholic or non alcoholic fatty liver disease. High-risk profiles of false negative/false positive of FibroTest, mainly Gilbert syndrome, hemolysis and acute inflammation, are present in 3% of the populations. In case of discordance between biopsy and FibroTest, half of the failures can be due to biopsy; the prognostic value of FibroTest is at least similar to that of biopsy in HCV, HBV and ALD. In conclusion this overview of evidence-based data suggests that biomarkers could be used as an alternative to liver biopsy for the first line assessment of fibrosis stage in the four most common chronic liver diseases, namely HCV, HBV, NAFLD and ALD. Neither biomarkers nor biopsy alone is sufficient for taking a definite decision in a given patient; all the clinical and biological data must be taken into account. There is no evidence based data justifying biopsy as a first line estimate of liver fibrosis. Health authorities in some countries have already approved validated biomarkers as the first line procedure for the staging of liver fibrosis.

Performance of transient elastography for the staging of liver fibrosis: a meta-analysis

BACKGROUND & AIMS

Transient elastography has been studied in a multitude of liver diseases for the staging of liver fibrosis with variable results. A meta-analysis was performed to assess the overall performance of transient elastography for the diagnosis of liver fibrosis and to analyze factors influencing the diagnostic accuracy.

METHODS

Literature databases and international conference abstracts were searched. Inclusion criteria were as follows: evaluation of transient elastography, liver biopsy as reference, and assessment of the area under the receiver operating characteristic curve (AUROC). The meta-analysis was performed using the random-effects model for the AUROC, summary receiver operating curve techniques, as well as meta-regression approaches.

RESULTS

Fifty studies were included in the analysis. The mean AUROC for the diagnosis of significant fibrosis, severe fibrosis, and cirrhosis were 0.84 (95% confidence interval [CI], 0.82-0.86), 0.89 (95% CI, 0.88-0.91), and 0.94 (95% CI, 0.93-0.95), respectively. For the diagnosis of significant fibrosis a significant reduction of heterogeneity of the AUROC was found when differentiating between the underlying liver diseases (P < .001). Other factors influencing the AUROC were the scoring system used and the country in which the study was performed. Age, body mass index, and biopsy quality did not have a significant effect on the AUROC.

CONCLUSIONS

Transient elastography can be performed with excellent diagnostic accuracy and independent of the underlying liver disease for the diagnosis of cirrhosis. However, for the diagnosis of significant fibrosis, a high variation of the AUROC was found that is dependent on the underlying liver disease.

Transient elastography is unreliable for detection of cirrhosis in patients with acute liver damage

Transient elastography [FibroScan (FS)] is a rapid, noninvasive, and reproducible method for measuring liver stiffness, which correlates with the degree of liver fibrosis in patients with chronic hepatitis. Whether FS is useful in the detection of preexisting liver fibrosis/cirrhosis in patients presenting with acute liver damage is unclear. Patients with acute liver damage of different etiologies were analyzed. Liver stiffness was measured during the acute phase of the liver damage and followed up to the end of the acute phase. A total of 20 patients were included in the study. In 15 of the 20 patients, initial liver stiffness values measured by FS during the acute phase of the liver damage were suggestive of liver cirrhosis. However, none of these 15 patients showed any signs of liver cirrhosis in the physical examination, ultrasound examination, or liver histology [performed in 11 of 15 (73%) patients]. A significant difference was observed in the initial bilirubin levels (5.8 +/- 6.5 mg/dL versus 15.7 +/- 11.8 mg/dL; P = 0.042) and age (32.4 +/- 17.5 years versus 49.7 +/- 15.8 years; P = 0.042) between patients with liver stiffness below or above 12.5 kPa. Six patients with initially high liver stiffness were followed up to abatement of the acute hepatitic phase; in all of them, liver stiffness values decreased to values below the cutoff value for liver cirrhosis.

CONCLUSION

Transient elastography frequently yields pathologically high values in patients with acute liver damage and is unsuitable for detecting cirrhosis/fibrosis in these patients.

Ultrasound-based transient elastography for the detection of hepatic fibrosis: systematic review and meta-analysis

BACKGROUND & AIMS

Ultrasound-based transient elastography is a promising noninvasive alternative to liver biopsy for detecting hepatic fibrosis. However, its overall test performance in various settings remains unknown. The aims of this study were to perform a systematic review and meta-analysis of diagnostic accuracy studies comparing ultrasound-based transient elastography with liver biopsy for hepatic fibrosis.

METHODS

Electronic and manual bibliographic searches to identify potential studies were performed. Selection of studies was based on reported accuracy of ultrasound-based transient elastography compared with liver biopsy. Data extraction was performed independently by 2 reviewers. Meta-analysis combined the sensitivities, specificities, and likelihood ratios of individual studies. Extent and reasons for heterogeneity were assessed.

RESULTS

Nine studies in full publication were identified. For patients with stage IV fibrosis (cirrhosis), the pooled estimates for sensitivity were 87% (95% confidence interval [CI], 84%-90%), specificity 91% (95% CI, 89%-92%), positive likelihood ratio 11.7 (95% CI, 7.9-17.1), and negative likelihood ratio 0.14 (95% CI, 0.10-0.20). Among 7 investigations reporting patients with stages II-IV fibrosis, the pooled estimates for sensitivity were 70% (95% CI, 67%-73%), specificity 84% (95% CI, 80%-88%), positive likelihood ratio 4.2 (95% CI, 2.4-7.2), and negative likelihood ratio 0.31 (95% CI, 0.23-0.43). Diagnostic threshold (or cut-off value) bias was identified as an important cause of heterogeneity for pooled results in both patient groups.

CONCLUSIONS

Ultrasound-based transient elastography appears to be a clinically useful test for detecting cirrhosis.