Controversies in liver biopsy: who, where, when, how, why?

A clinical and histopathologic perspective on evolving noninvasive and invasive alternatives for liver biopsy

Noninvasive or minimally invasive alternatives are proposed as substitutes for liver biopsy and include clinical indices, cross-sectional imaging, serum biomarkers, liver stiffness measurement, and portal pressure measurement. Most alternatives to liver biopsy assess one aspect of liver disease and translate this into a numeric score. Overlap between categories may limit applications. Liver biopsy provides information about numerous variables: tissue architectural changes; necroinflammatory injury; fibrotic stage; alterations of parenchyma and bile duct epithelium; accumulation of fat, copper, and iron; and molecular and genetic changes. Liver biopsy may identify multiple disease etiologies. A single numeric score cannot be a substitute for complete histologic assessment. However, within defined clinical contexts, noninvasive assessment is an attractive alternative for many patients given the ease, avoidance of risk from invasive procedures, and validated contribution to clinical management. Serum biomarkers and liver stiffness assessment may become indispensable in longitudinal studies and to document outcome of treatments. The accuracy of the more reliable techniques is typically around 80%. Neither liver biopsy nor any single alternative option represents an absolute assessment of liver disease. Biopsy and alternatives are not mutually exclusive options. Liver biopsy and the noninvasive alternatives require a clear understanding of significance and limitations of each investigation. This places a responsibility on the clinician to consider fully the results of any of the investigative options used within the diagnostic and prognostic context of each individual patient, and to choose critically the most appropriate investigations for the patient's needs.

FibroTest and FibroScan for the prediction of hepatitis C-related fibrosis: a systematic review of diagnostic test accuracy

BACKGROUND

The accurate diagnosis of hepatitis C virus (HCV)-related fibrosis is crucial for prognostication and treatment decisions. Due to the limitations of biopsy, noninvasive alternatives including FibroTest and FibroScan have been developed. Our objective was to systematically review studies describing the accuracy of these tests for predicting HCV-related fibrosis.

METHODS

Studies comparing FibroTest or FibroScan versus biopsy in HCV patients were identified via an electronic search. Random effects meta-analyses and areas under summary receiver operating characteristics curves (AUC) were examined to characterize test accuracy for significant fibrosis (F2-4) and cirrhosis. Heterogeneity was explored using meta-regression.

RESULTS

Twelve studies were identified, 9 for FibroTest (N = 1,679) and 4 for FibroScan (N = 546). In heterogeneous analyses for significant fibrosis, the AUCs for FibroTest and FibroScan were 0.81 (95% CI 0.78-84) and 0.83 (0.03-1.00), respectively. At a threshold of approximately 0.60, the sensitivity and specificity of the FibroTest were 47% (35-59%) and 90% (87-92%). For FibroScan (threshold approximately 8 kPa), corresponding values were 64% (50-76%) and 87% (80-91%), respectively. Methodological quality, the length of liver biopsy specimens, and inclusion of special populations did not explain the observed heterogeneity. However, the diagnostic accuracy of both measures was associated with the prevalence of significant fibrosis and cirrhosis in the study populations. For cirrhosis, the summary AUCs for FibroTest and FibroScan were 0.90 (95% CI not calculable) and 0.95 (0.87-0.99), respectively.

CONCLUSIONS

FibroTest and FibroScan have excellent utility for the identification of HCV-related cirrhosis, but lesser accuracy for earlier stages. Refinements are necessary before these tests can replace liver biopsy.

Review article: a pharmacoeconomic analysis of thrombocytopenia in chronic liver disease

BACKGROUND

Patients with chronic liver disease commonly experience thrombocytopenia resulting from disease or treatment. Such patients often require multiple platelet transfusions, and consequently can experience associated complications including systemic infection, iron overload, and platelet refractoriness.

AIM

To discuss the limited data available on the impact of thrombocytopenia on the medical procedures and their associated costs.

RESULTS

Thrombocytopenia and its treatment can have a negative impact on outcomes and cost of therapy; costs associated with platelet transfusion can constitute a significant portion of the hospital budget. Inability to initiate or complete antiviral therapy for chronic hepatitis C infection due to low platelet counts can lead to dose reduction or discontinuation, lower efficacy, increased risks, and increased overall costs. Routine medical procedures can be complicated, prolonged, or precluded as a result of severe thrombocytopenia.

CONCLUSION

Novel therapies can safely and effectively prevent or treat thrombocytopenia in this patient population with chronic liver disease resulting in improved quality of care and significant cost savings in addition to improving treatment outcomes and quality of life (QOL) measures.

Review article: thrombocytopenia in chronic liver disease

BACKGROUND

Thrombocytopenia is a common finding in advanced liver disease. It is predominantly a result of portal hypertension and platelet sequestration in the enlarged spleen, but other mechanisms may contribute. The liver is the site of thrombopoietin (TPO) synthesis, a hormone that leads to proliferation and differentiation of megakaryocytes and platelet formation. Reduced TPO production further reduces measurable serum platelet counts.

AIM

This paper describes the scope of thrombocytopenia in chronic liver disease and assesses the clinical impact in this patient population.

METHODS

A medline review of the literature was performed pertaining to thrombocytopenia and advanced liver disease. This data is compiled into a review of the impact of low platelets in liver disease.

RESULTS

The incidence of thrombocytopenia, its impact on clinical decision making and the use of platelet transfusions are addressed. Emerging novel therapeutics for thrombocytopenia is also discussed.

CONCLUSIONS

Thrombocytopenia is a common and challenging clinical disorder in patients with chronic liver disease. New therapeutic options are needed to safely increase platelet counts prior to invasive medical procedures as well as to counteract therapies that further exacerbate low platelets, such as interferon. An ideal compound would be orally available and safe, with rapid onset of action.

[Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis]

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are the hepatic manifestations of the metabolic syndrome. Since the prevalence of obesity and consequently of the metabolic syndrome is steadily increasing, the different types of NAFLD are nowadays the most common cause of liver injury in North America. The development of NASH and fatty liver cirrhosis occurs after a "two-hit-theory", in which hepatic steatosis is followed by lipid peroxidation, the production of cytokines and the induction of Fas ligand. A standardized drug based therapy does not exist so far, but glitazones have emerged as a promising treatment option. However, since the disease is related to Western lifestyle, treatment should be based on prevention and changes in lifestyle.

Diagnostic accuracy of the aspartate aminotransferase-to-platelet ratio index for the prediction of hepatitis C-related fibrosis: a systematic review

The development of noninvasive markers of liver fibrosis is a clinical and research priority. The aspartate aminotransferase-to-platelet ratio index (APRI) is a promising tool with limited expense and widespread availability. Our objective was to systematically review the performance of the APRI in hepatitis C virus (HCV)-infected patients. Random effects meta-analyses and areas under summary receiver operating characteristic curves (AUC) were examined to characterize APRI accuracy for significant fibrosis (stages 2-4) and cirrhosis. In 22 studies (n = 4,266), the summary AUCs of the APRI for significant fibrosis and cirrhosis were 0.76 [95% confidence interval (CI), 0.74-0.79] and 0.82 (95%CI, 0.79-0.86), respectively. For significant fibrosis, an APRI threshold of 0.5 was 81% sensitive and 50% specific. At a 40% prevalence of significant fibrosis, this threshold had a negative predictive value (NPV) of 80%, but could reduce the necessity of liver biopsy by only 35%. For cirrhosis, a threshold of 1.0 was 76% sensitive and 71% specific. At a 15% cirrhosis prevalence, the NPV of this threshold was 91%. Higher APRI thresholds had suboptimal positive predictive values except in settings with a high prevalence of cirrhosis. APRI accuracy was not affected by the prevalence of advanced fibrosis, or study and biopsy quality. However, the accuracy for cirrhosis was greater in studies including human immunodeficiency virus (HIV)/HCV-co-infected patients.

CONCLUSION

The major strength of the APRI is the exclusion of significant HCV-related fibrosis. Future studies of novel markers should demonstrate improved accuracy and cost-effectiveness compared with this economical and widely available index.

Psoriasis patients with diabetes type 2 are at high risk of developing liver fibrosis during methotrexate treatment

BACKGROUND/AIMS

We investigated the impact of diabetes mellitus type 2, overweight, alcohol over-consumption, and chronic hepatitis B or C as risk factors, for liver fibrosis in psoriasis patients treated with methotrexate.

METHODS

One hundred and sixty-nine liver biopsies from 71 patients who underwent liver biopsies as part of the monitoring of methotrexate treatment for psoriasis were reviewed. Fibrosis, steatosis and inflammation were staged according to the NAFLD activity score.

RESULTS

Twenty-six patients had one or more of the risk factors and 25 (96%) of these (median cumulative dose methotrexate 1500 mg) developed liver fibrosis. Of those without risk factor, 26 (58%) (p=0.012) developed fibrosis (median cumulative dose methotrexate 2100 mg). Ten (38%) of the patients with risk factor(s) had severe fibrosis (stage 3-4) (mean cumulative dose methotrexate 1600 mg), while four (9%) (p=0.0012) of those without risk factors had severe fibrosis (median cumulative dose methotrexate 1900 mg).

CONCLUSIONS

Patients with methotrexate treated psoriasis and risk factors for liver disease, especially diabetes type 2 or overweight, are at higher risk of developing severe liver fibrosis compared to those without such risk factors, even when lower cumulative methotrexate doses are given.

Non-alcoholic fatty liver disease in the Asia-Pacific region: definitions and overview of proposed guidelines

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western industrialized countries, affecting 20-40% of the general population. Large population-based surveys in China, Japan, and Korea indicate that the prevalence of NAFLD is now 12% to 24% in population subgroups, depending on age, gender, ethnicity, and location (urban versus rural). There is strong evidence that the prevalence of NAFLD has increased recently in parallel with regional trends in obesity, type 2 diabetes, and metabolic syndrome; and that further increases are likely. The relationship between NAFLD, central obesity, diabetes, and metabolic syndrome is clearly evident in retrospective and prospective Asian studies, but the strength of association with these metabolic risk factors is only appreciated when regional definitions of anthropometry are used. Pathological definition of NAFLD, particularly its activity and the extent of liver fibrosis, requires histological examination, but liver biopsy is often not appropriate in this disorder for logistic reasons. An alternative set of operational definitions is proposed here. Clinicians need guidelines as how best to diagnose and manage NAFLD and its associated metabolic disorders in countries with scant healthcare resources. The Asia-Pacific Working Party (APWP) for NAFLD was convened to collate evidence and deliberate these issues. Draft proposals were presented and discussed at Asia-Pacific Digestive Week at Cebu, Philippines, in late November 2006, and are published separately in this issue of the Journal as an Executive Summary. The present document reviews the reasoning and evidence behind the APWP-NAFLD proposals for definition, assessment, and management of NAFLD in the Asia-Pacific region.

Incidence of arterial injuries detected by arteriography following percutaneous right-lobe ultrasound-guided core liver biopsies in human subjects

PURPOSE

To determine the incidence and significance of arterial injuries detected by angiography subsequent to ultrasound-guided random core liver biopsies in normal healthy adults.

MATERIALS AND METHODS

Retrospective analysis of 55 potential living related liver donors who underwent an ultrasound-guided random liver biopsy and a visceral angiogram was performed (January, 1999 to May, 2002). All liver biopsy samples (obtained by 2-3 18-gauge needle passes) were re-evaluated prospectively by a transplant pathologist for adequacy (defined: >or=5 complete portal triads). Subjects who underwent angiograms before the biopsy or >7 days after the biopsy were excluded from the arterial injury evaluation. Angiograms were reviewed by two angiographers. Arterial injuries were identified and classified by consensus into contusions, active bleeding, arterial-venous fistulae, and pseudoaneurysms.

RESULTS

Mean needle pass was 2.1. No major complications were encountered. All samples were deemed pathologically adequate. Forty-eight potential donors were included for the arterial injury evaluation. Three arterial injuries (two arterioportal fistulae, 4.2%) were found in 48 angiograms (6.3%). None of the three injuries required intervention.

CONCLUSION

The incidence of arterioportal fistulae following core liver biopsies has not changed over the past three decades despite improvement in biopsy needle technology, reduction of needle caliber, and the use of image guidance.

Intraoperative detection of cell injury and cell death with an 800 nm near-infrared fluorescent annexin V derivative

The intraoperative detection of cell injury and cell death is fundamental to human surgeries such as organ transplantation and resection. Because of low autofluorescence background and relatively high tissue penetration, invisible light in the 800 nm region provides sensitive detection of disease pathology without changing the appearance of the surgical field. In order to provide surgeons with real-time intraoperative detection of cell injury and death after ischemia/reperfusion (I/R), we have developed a bioactive derivative of human annexin V (annexin800), which fluoresces at 800 nm. Total fluorescence yield, as a function of bioactivity, was optimized in vitro, and final performance was assessed in vivo. In liver, intestine and heart animal models of I/R, an optimal signal to background ratio was obtained 30 min after intravenous injection of annexin800, and histology confirmed concordance between planar reflectance images and actual deep tissue injury. In summary, annexin800 permits sensitive, real-time detection of cell injury and cell death after I/R in the intraoperative setting, and can be used during a variety of surgeries for rapid assessment of tissue and organ status.

Safety and Efficacy of Fluoroscopic versus Ultrasound Guidance for Core Liver Biopsies in Potential Living Related Liver Transplant Donors: Preliminary Results

PURPOSE

To describe and evaluate the safety and efficacy of fluoroscopically guided percutaneous liver biopsies in comparison with ultrasound (US)-guided percutaneous liver biopsies in potential living related liver donors.

MATERIALS AND METHODS

Retrospective analysis of 133 consecutive preoperative workups of potential living related liver donors was performed. The subjects were treated from January 1999 through May 2002. Subjects were divided into those who underwent US-guided subcostal 18-gauge core liver biopsies (group I) and those who underwent fluoroscopically guided intercostal 18-gauge core liver biopsies (group II). Group II biopsies were performed in a manner similar to percutaneous transhepatic cholangiography. All samples obtained during the study period were reevaluated prospectively by a transplant pathologist blinded to guidance modality for sample adequacy (defined as >or=5 complete portal triads). Subjects were followed for 4 hours before discharge and afterward in the transplant clinic until donation. Subjects who did not donate organs were followed for at least 1 month.

RESULTS

One hundred thirty-three potential donors were evaluated (55 for group I, 78 for group II). Mean follow-up was 1.7 months, and 77% of subjects donated. The mean numbers of needle passes were 2.1 and 2.3 for groups I and II, respectively. No major complications were encountered, and all subjects were discharged in 4 hours. Incidences of minor complications were 3.6% (vasovagal reactions) and zero for groups I and II, respectively. Sample adequacy rates were 100% and 99% for groups I and II, respectively. One case (1.8%) in group I, although pathologically adequate, had additional renal tissue.

CONCLUSION

Fluoroscopically guided liver biopsy shows encouraging initial safety results and is as effective as US-guided liver biopsy in normal subjects.

Nonalcoholic fatty liver disease: from steatosis to cirrhosis

Nonalcoholic steatohepatitis (NASH), the lynchpin between steatosis and cirrhosis in the spectrum of nonalcoholic fatty liver disorders (NAFLD), was barely recognized in 1981. NAFLD is now present in 17% to 33% of Americans, has a worldwide distribution, and parallels the frequency of central adiposity, obesity, insulin resistance, metabolic syndrome and type 2 diabetes. NASH could be present in one third of NAFLD cases. Age, activity of steatohepatitis, and established fibrosis predispose to cirrhosis, which has a 7- to 10-year liver-related mortality of 12% to 25%. Many cases of cryptogenic cirrhosis are likely endstage NASH. While endstage NAFLD currently accounts for 4% to 10% of liver transplants, this may soon rise. Pathogenic concepts for NAFLD/NASH must account for the strong links with overnutrition and underactivity, insulin resistance, and genetic factors. Lipotoxicity, oxidative stress, cytokines, and other proinflammatory mediators may each play a role in transition of steatosis to NASH. The present "gold standard" management of NASH is modest weight reduction, particularly correction of central obesity achieved by combining dietary measures with increased physical activity. Whether achieved by "lifestyle adjustment" or anti-obesity surgery, this improves insulin resistance and reverses steatosis, hepatocellular injury, inflammation, and fibrosis. The same potential for "unwinding" fibrotic NASH is indicated by studies of the peroxisome proliferation activator receptor (PPAR)-gamma agonist "glitazones," but these agents may improve liver disease at the expense of worsening obesity. Future challenges are to approach NAFLD as a preventive public health initiative and to motivate affected persons to adopt a healthier lifestyle.