Predictors of nonalcoholic steatohepatitis in patients undergoing bariatric surgery: when is liver biopsy indicated? Surg Obes Relat Dis. 2008;4:612-617. [PMID: 18226970 DOI: 10.1016/j.soard.2007.11.007]

American society for metabolic and bariatric surgery: intra-operative care pathway for minimally invasive Roux-en-Y gastric bypass

BACKGROUND

Clinical care pathways help guide and provide structure to clinicians and providers to improve healthcare delivery and quality. The Quality Improvement and Patient Safety Committee (QIPS) of the American Society for Metabolic and Bariatric Surgery (ASMBS) has previously published care pathways for the performance of laparoscopic sleeve gastrectomy (LSG) and pre-operative care of patients undergoing Roux-en-Y gastric bypass (RYGB).

OBJECTIVE

This current RYGB care pathway was created to address intraoperative care, defined as care occurring on the day of surgery from the preoperative holding area, through the operating room, and into the postanesthesia care unit (PACU).

METHODS

PubMed queries were performed from January 2001 to December 2019 and reviewed according to Level of Evidence regarding specific key questions developed by the committee.

RESULTS

Evidence-based recommendations are made for care of patients undergoing RYGB including the pre-operative holding area, intra-operative management and performance of RYGB, and concurrent procedures.

CONCLUSIONS

This document may provide guidance based on recent evidence to bariatric surgeons and providers for the intra-operative care for minimally invasive RYGB.

Apprising the choice of bariatric surgery in patients with compensated cirrhosis with morbid obesity: results of a national analysis

Bariatric surgery (BS) was proved safe in carefully selected patients with compensated cirrhosis (CC). However, limited data exist on differential impact of bariatric surgery type on clinical outcomes and health care utilization. This retrospective study utilizes the 2010-2014 Nationwide Readmissions Database. We included obese adults with CC who underwent the two most commonly used BS, Roux-en-Y (RYGB) and laparoscopic sleeve gastrectomy (LSG). Those with decompensation within 6 months of BS were excluded. Rates of hepatic decompensation (new-onset ascites, variceal bleed, encephalopathy, spontaneous bacterial peritonitis, and/or hepatorenal syndrome), surgical complications, health care utilization, and mortality were compared between RYGB and LSG. Multivariable analysis was performed to fit various models. A total of 3032 patients with CC underwent BS, including 1864 (61.5%) RYGB and 1168 (38.5%) LSG. The majority (56%) of BS were performed at large, metropolitan teaching hospitals. There were no significant differences in various decompensations and surgical complications comparing RYGB to LSG. Healthcare utilization including index length of stay (RYGB: 3.4 days vs LSG: 3.0 days), 30-day readmission rate (RYGB: 9.5% vs LSG: 3.7%), and cost of admission (RYGB: $14,006 vs LSG: $12,523) were higher in RYGB (p values < 0.001). Index admission and calendar year mortality could not be analyzed due to the few number of events. Two types of bariatric surgeries in obese patients with compensated cirrhosis have similar rates of decompensated cirrhosis events and surgical complications. However, RYGB procedure incurred increased healthcare utilization. Therefore, LSG may be the preferred BS for patients with CC. Prospective, randomized studies comparing the types of BS are needed to confirm our observations.

Differential Outcomes and Clinical Challenges of NAFLD With Extreme Obesity

Nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity. The prevalence of extreme obesity, defined as body mass index (BMI) of 50 kg/m² or higher, is rising more rapidly than overall obesity. We aimed to compare the clinical outcomes and performance of noninvasive fibrosis assessment tools in NAFLD with or without extreme obesity. A retrospective analysis was performed in 304 patients with NAFLD with extreme obesity and compared them to patients with NAFLD with BMI of 40 kg/m² or less, matched for age, gender, race, and liver fibrosis stage. The mean age of the NAFLD with extreme obesity cohort was 55.9 years, BMI 55 kg/m², and 49.7% had cirrhosis at initial evaluation. Baseline cirrhosis and coronary artery disease were associated with increased risk of death, and dyslipidemia with decreased risk of mortality. Age, insulin use, hypertension, albumin and platelet count were associated with cirrhosis. Fifteen percent of patients had weight‐loss surgery, but this was not associated with survival or risk of cirrhosis. Of the 850 abdominal ultrasound scans performed in 255 patients, 24.1% were deemed suboptimal for hepatocellular carcinoma screening. The mean NAFLD fibrosis score (NFS) in the extreme obesity cohort, versus a propensity‐matched cohort with BMI of 40 kg/m² or less, was significantly different for both low fibrosis (F0‐F2) (0.222 vs. −1.682, P < 0.0001) and high fibrosis (F3‐F4) (2.216 vs. 0.557, P < 0.001). Conclusion: NAFLD with extreme obesity is associated with increased risk of liver‐related and overall mortality. Accurate noninvasive assessment of liver fibrosis, low rates of weight loss surgery, and high failure rate of ultrasound were identified as clinical challenges in this population.

Safety and Utility of Liver Biopsy During Bariatric Surgery in the New Zealand Setting

BACKGROUND

Asymptomatic liver disease is common in bariatric patients and can be diagnosed with intraoperative biopsy. This study aimed to establish the risk-benefit profile of routine liver biopsy, prevalence of clinically significant liver disease, relationship between liver pathology and body mass index, and compare outcomes between ethnic groups.

METHODS

This retrospective cohort study included all patients who had index bariatric surgery at Auckland City Hospital between 2009 and 2016. Diagnosis of liver disease was based on intraoperative biopsy histology. Outcomes included safety (biopsy-related complication) and utility (liver pathology meeting criteria for referral). Liver pathology and referral rates were compared between ethnic groups.

RESULTS

Of 335 bariatric surgery patients, 234 (70%) underwent intraoperative liver biopsy. There were no biopsy-related complications. Histological findings were as follows: normal 25/234 (11%), non-alcoholic fatty liver disease (NAFLD) 207/234 (88%), and other pathological findings in 35/234 (15%). Histological finding meeting referral criteria was present in 22/234 (9%). Of these, 12/22 (55%) were referred. Number needed to biopsy to identify histology meeting referral criteria: n = 11. Māori had a similar NAFLD rate to non-Māori [51/56 versus 156/178, p = 0.48]. Pasifika patients had a higher rate than non-Pasifika [39/40 versus 168/194, p = 0.049]. Māori and Pasifika patients had similar referral rates to non-Māori and non-Pasifika [2/3 versus 5/9, p = 0.73; 2/2 versus 5/10, p = 0.19].

CONCLUSIONS

Intraoperative liver biopsy during bariatric surgery is safe and identified liver disease in 89%, with 9% meeting referral criteria. Pasifika patients have a higher rate of NAFLD than non-Pasifika.

Influence of Liver Disease on Perioperative Outcome After Bariatric Surgery in a Northern German Cohort

OBJECTIVES

The aim of this study was to assess the prevalence of non-alcoholic fatty liver disease (NAFLD) in morbidly obese patients and evaluate the influence on perioperative complications.

BACKGROUND

Patients undergoing bariatric surgery have a high incidence of non-alcoholic steatohepatitis (NASH). Upcoming data indicates that liver disease has a significant effect on perioperative complications. However, the influence of NAFLD/NASH on perioperative outcome in bariatric patients is still controversial.

METHODS

We identified a total of 302 patients with concomitant liver biopsies, while performing either laparoscopic Roux-Y gastric bypass or sleeve gastrectomy. Liver biopsy was performed in case of abnormal liver appearance at time of bariatric surgery. Histological results were compared to perioperative complication rate.

RESULTS

NAFLD is common in our patient cohort. Abnormal findings in liver histology were found in 82.3 % of our patients. Liver cirrhosis was newly diagnosed in 12 patients (4 %). There were no complications due to liver biopsy. The mortality rate was 0.3 %, leakage rate was 1 %, and postoperative bleeding occurred in 3.3 %. Pulmonary complications were observed in 1.7 % and cardiovascular complications in 1.3 %. One patient developed portal vein thrombosis and one patient acute pancreatitis; both were treated conservatively. No patient had postoperative liver failure. We found no association between histological findings and perioperative outcomes.

CONCLUSIONS

The prevalence of NAFLD among morbidly obese surgical patients was high, although this condition was not associated with increased risk for postoperative complications. Because of unexpected findings in intraoperative liver biopsies, the routine indication of liver biopsies in patients at high risk for liver disease should be discussed.

Utility of Ultrasound, Transaminases, and Visual Inspection to Assess Nonalcoholic Fatty Liver Disease in Bariatric Surgery Patients

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is common in adults with extreme obesity and can impact long-term health and survival. Liver biopsy is the only accurate test for diagnosis and staging, but is invasive and costly. Non-invasive testing offers an attractive alternate, but the overall accuracy remains a significant issue. This study was conducted to determine the accuracy and clinical utility of pre-operative ultrasound and liver transaminase levels, as well as intra-operative hepatic visual inspection, for assessing presence of NAFLD as confirmed by hepatic histology.

METHODS

Data was collected prospectively from 580 morbidly obese adult patients who underwent Roux-en-Y gastric bypass surgery with intraoperative wedge biopsy between January 2004 and February 2009. Complete data for ultrasound, ALT and AST levels, and documented visual inspection was available for 513 patients.

RESULTS

The prevalence of NAFLD was 69 % and that of NASH was 32 %. The individual non-invasive clinical assessments demonstrated low sensitivity, specificity, and accuracy for detecting the presence of steatosis, steatohepatitis, or fibrosis. The combination of normal or abnormal results for all tests improved predictive utility. Abnormal tests with all three assessments had a sensitivity of 95-98 % and a specificity of 28-48 % for major histologic findings in NAFLD/NASH. Normal tests with all three assessments had a sensitivity of 12-22 % and a specificity of 89-97 % for major histologic findings in NAFLD/NASH.

CONCLUSIONS

Although individual clinical tests for NAFLD have limited accuracy, the use of combined clinical tests may prove useful.

Challenges and Management of Liver Cirrhosis: Practical Issues in the Therapy of Patients with Cirrhosis due to NAFLD and NASH

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and comprises a liver disease spectrum ranging from steatosis to nonalcoholic steatohepatitis (NASH) with risk of progression to liver cirrhosis and hepatocellular carcinoma (HCC). Associated metabolic conditions and comorbidities such as obesity, diabetes and cardiovascular diseases are common and require concerted management. Adiponutrin (PNPLA3) variants may help to identify NAFLD patients at higher risk for liver disease progression towards advanced fibrosis and HCC. The therapeutic options in NAFLD/NASH include lifestyle modification, pharmacological treatment, bariatric surgery for patients with morbid obesity and treatment of complications of liver cirrhosis and HCC, including liver transplantation. Insulin sensitizers and antioxidative treatment strategies with vitamin E are among the best-established pharmacological approaches, but both drugs have long-term safety issues and there is limited evidence in cirrhotic patients. Treatment of concomitant/underlying metabolic conditions with statins or metformin may also have beneficial effects on portal hypertension, complications of liver cirrhosis and HCC prevention. The bile acid receptor FXR may be a promising novel therapeutic target for the treatment of NAFLD/NASH, fibrosis and portal hypertension, but the prognostic implications of associated changes in low- and high-density lipoprotein cholesterol require further studies. Morbidly obese NASH patients can benefit from bariatric surgery which may reduce liver fibrosis but carries a risk of decompensation in patients with advanced liver cirrhosis. When carefully selected, patients with NASH cirrhosis undergoing liver transplantation have a good outcome. This review summarizes recent progress in the management of patients with liver cirrhosis due to NASH.

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the Western world. It is closely associated with metabolic syndrome. The alarming epidemics of diabetes and obesity have fueled an increasing prevalence of NAFLD, particularly among these high-risk groups. Histologically, NAFLD encompasses a disease spectrum ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), which is characterized by hepatocyte injury, inflammation, and variable degrees of fibrosis on liver biopsy. Non-alcoholic steatohepatitis can progress to cirrhosis in a fraction of patients. There is currently little understanding of risk factors for disease progression and the disease pathogenesis has not been fully defined. Liver biopsy remains the gold standard for diagnosis. Weight loss, dietary modification, and the treatment of underlying metabolic syndrome remain the mainstays of therapy once the diagnosis is established. There are no well-established pharmacological agents for treatment of NASH, although this is a subject of ongoing research.

Increased perioperative mortality following bariatric surgery among patients with cirrhosis

BACKGROUND & AIMS

The prevalence of nonalcoholic fatty liver disease and ensuing cirrhosis is expected to increase as a result of the obesity epidemic. These trends might increase the number of bariatric surgeries among patients with cirrhosis. We sought to assess the impact of cirrhosis on perioperative mortality after bariatric procedures.

METHODS

Data on patients who underwent bariatric surgery in the United States between 1998 and 2007 were extracted from the Nationwide Inpatient Sample. In-hospital mortality and length of stay were compared for patients with no cirrhosis, compensated cirrhosis, and decompensated cirrhosis.

RESULTS

Patients without cirrhosis had lower mortality rates than those with compensated and decompensated cirrhosis (0.3% vs 0.9% and 16.3%, respectively, P = .0002). After adjusting for covariates, the adjusted odds ratio of mortality among compensated and decompensated cirrhotic patients compared with noncirrhotic patients was 2.17 (95% confidence interval, 1.03-4.55) and 21.2 (95% confidence interval, 5.39-82.9), respectively. Mortality increased with volume of surgery among centers; those with more than 100 surgeries per year had the lowest mortality rates, compared with those with 50 to 100 surgeries per year and fewer than 50 surgeries per year (0.2% vs 0.4% and 0.7%, respectively; P < .0001). The average length of stay was longer for patients with decompensated and compensated cirrhosis, compared with patients without liver disease (6.7 and 4.4 d vs 3.2 d, respectively; P = .0001 and P = .03).

CONCLUSIONS

Bariatric surgery in patients with cirrhosis should be performed while liver disease is well compensated. Patients with cirrhosis should undergo surgery at centers that perform large numbers of these procedures.

Noninvasive predictors for liver fibrosis in patients with nonalcoholic steatohepatitis

AIM

To evaluate certain anthropometric, clinical and laboratory features indicating liver fibrosis in nonalcoholic steatohepatitis and to establish the noninvasive markers for liver fibrosis.

METHODS

Eighty-one patients (40 male, 41 female) who were diagnosed with fatty liver by ultrasonographic examination and fulfilled the inclusion criteria participated in the study. Anamnesis, anthropometric, clinical and laboratory features of all cases were recorded and then liver biopsy was performed after obtaining patient consent. Steatosis, necroinflammation and liver fibrosis were examined according to age ≥ 45, gender, body mass index, central obesity, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) > 1, γ-glutamyltransferase (GGT)/ALT > 1, platelet count, insulin, c-peptide levels and the presence of hypertension, diabetes, hypertriglyceridemia and insulin resistance.

RESULTS

Eighty-one patients with non-alcoholic steatohepatitis (NASH) enrolled in the study. 69 of 81 patients were diagnosed with NASH, 11 were diagnosed with simple fatty liver and 1 was diagnosed with cirrhosis. AST/ALT > 1, GGT/ALT > 11, high serum ferritin and fasting insulin levels, the presence of diabetes, hypertension, hypertriglyceridemia and insulin resistance seemed to enhance the severity of steatosis, necroinflammation and fibrosis but these results were not statistically significant.

CONCLUSION

Liver steatosis and fibrosis can occur in individuals with normal weight. There was no significant concordance between severity of liver histology and the presence of predictors for liver fibrosis including metabolic risk factors.

Serum proteomic analysis of diet-induced steatohepatitis and metabolic syndrome in the Ossabaw miniature swine

We recently developed a nutritional model of steatohepatitis and metabolic syndrome in Ossabaw pigs. Here we describe changes in the serum proteome of pigs fed standard chow (control group; n = 7), atherogenic diet (n = 5), or modified atherogenic diet (M-ath diet group; n = 6). Pigs fed atherogenic diet developed metabolic syndrome and mildly abnormal liver histology, whereas pigs fed M-ath diet exhibited severe metabolic syndrome and liver injury closely resembling human nonalcoholic steatohepatitis (NASH). Using a label-free mass spectrometry-based proteomics approach, we identified 1,096 serum proteins, 162 of which changed significantly between any two diet groups (false discovery rate <5%). Biological classification of proteins with significant changes revealed functions previously implicated in development of NASH in humans, including immune system regulation and inflammation (orosomucoid 1, serum amyloid P component, paraoxonase 1, protein similar to alpha-2-macroglobulin precursor, beta-2-microglobulin, p101 protein, and complement components 2 and C8G), lipid metabolism (apolipoproteins C-III, E, E precursor, B, and N), structural and extracellular matrix proteins (transthyretin and endopeptidase 24.16 type M2), and coagulation [carboxypeptidase B2 (plasma)]. Several proteins with significant differential expression in pigs were also identified in our recent human proteomics study as changing significantly in serum from patients across the spectrum of nonalcoholic fatty liver disease, including apolipoproteins C-III and B, orosomucoid 1, serum amyloid P component, transthyretin, paraoxonase 1, and a protein similar to alpha-2-macroglobulin precursor. This serum proteomic analysis provides additional information about the pathogenesis of NASH and further characterizes our large animal model of diet-induced steatohepatitis and metabolic syndrome in Ossabaw pigs.

The incapacity of the surgeon to identify NASH in bariatric surgery makes biopsy mandatory

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a morbid condition highly related to obesity. It is unclear if the macroscopic liver appearance correlates with the histopathologic findings. The goal of this prospective study was to determine the relationship between the intraoperative liver appearance and the histopathologic diagnosis of NASH in morbidly obese subjects undergoing bariatric surgery. We also aimed to determine variables that could predict NASH preoperatively.

METHODS

Consecutive 51 subjects undergoing bariatric surgery without evidence of other liver disease underwent intraoperative liver biopsy. An intraoperative liver visual (macroscopic and tactile examination) was recorded. The liver aspect was compared with the liver histologic findings. Histological assessment was categorized into two groups: NASH and non-NASH (including normal histology and simple steatosis). Clinical and biochemical parameters were obtained from the patient databases and were compared between groups to identify preoperatively predictive factors of NASH.

RESULTS

From 51 patients, only one presented totally normal histology. Forty-three (86.2%) presented simple steatosis, and seven (13.7%) were classified as NASH. Clinical parameters were not different between groups. At biochemical analysis, only VLDL cholesterol level was significantly higher in the NASH group (p=0.037) but yet within the normal range. Association between macroscopic liver appearance and the presence of histological NASH is poor (sensitivity of 14%, specificity of 56%, positive predictive value of 5%, and negative predictive value of 80%).

CONCLUSIONS

No predictor of NASH was found. Surgeons' evaluation could not identify NASH individuals. Routine liver biopsy during bariatric operations is mandatory to differentiate NASH and nonalcoholic fatty liver disease.

Methods for assessing intrahepatic fat content and steatosis

PURPOSE OF REVIEW

Intrahepatic fat content is increasingly being recognized as an integral part of metabolic dysfunction. This article reviews available methods for the assessment of hepatic steatosis.

RECENT FINDINGS

Apart from liver biopsy, there are several noninvasive radiologic modalities for evaluating nonalcoholic fatty liver disease. Ultrasonography, computed tomography, and traditional MRI remain largely qualitative methods for detecting mild to severe degrees of steatosis rather than quantitative methods for measuring liver fat content, even though novel attempts to collect objective quantitative information have recently been developed. Still, their sensitivity at mild degrees of steatosis is poor. Undoubtedly, most methodological advances have occurred in the field of MRI and magnetic resonance spectroscopy, which currently enable the accurate quantification of intrahepatic fat even at normal or near normal levels. Xenon computed tomography was also recently shown to offer another objective tool for the quantitative assessment of steatosis, although more validation studies are required.

SUMMARY

Several modalities can be used for measuring intrahepatic fat and assessing steatosis; the choice will ultimately depend on the intended use and available resources.