Functional Liver Recovery After Bariatric Surgery--a Prospective Cohort Study with the LiMAx Test

A hypocaloric protein-rich diet before metabolic surgery improves liver function in patients with obesity and diabetes : A secondary analysis of a randomized clinical trial

PURPOSE

Obesity and type 2 diabetes (T2DM) are major risk factors for hepatic steatosis. Diet or bariatric surgery can reduce liver volume, fat content, and inflammation. However, little is known about their effects on liver function, as evaluated here using the LiMAx test.

METHODS

In the MetaSurg study (RCT on the effects of different Roux-en-Y gastric bypass (RYGB) limb lengths on diabetes remission in patients with BMI ≥ 27 to ≤ 60 kg/m2 and T2DM; trial registration: DRKS00007810, German Clinical Trials Register Freiburg), 24 consecutive patients underwent liver function (LiMAx) and imaging assessments (MRI, transient elastography; TE) before and after diet and surgery. Two weeks before surgery, the patients received a hypocaloric protein-rich diet.

RESULTS

Nine of 18 patients had a pathologic LiMAx value (≤ 315 µg/kg/h) at baseline. After two weeks of diet, LiMAx values improved (p = 0.01, paired t test, n = 15). LiMAx values further recovered six months after RYGB (p = 0.01, paired t test, n = 15), which was accompanied by decreased liver volumes (p = 0.005, paired t test, n = 10), proton density fat fraction (p = 0.003, paired t test, n = 12), and TE measurements (p = 0.032, paired t test, n = 14). The need for medical diabetes treatment decreased from 100 to 35%.

CONCLUSION

Liver function improved after a two-week hypocaloric protein-rich diet and metabolic surgery in patients with obesity and T2DM. These data suggest that a two-week diet for this group of patients prior to abdominal surgery could improve a presumably impaired liver function.

Comparison of different liver fibrosis scores following sleeve gastrectomy

PURPOSE

The prevalence of obesity, along with that of its associated health conditions, including cardiovascular diseases, diabetes mellitus, and liver diseases, such as non-alcoholic fatty liver disease (NAFLD), is increasing annually. Bariatric surgery is indicated for the treatment of obesity if conservative treatment fails. While various liver fibrosis scores have been proposed for assessing liver function, they are typically used prior to bariatric surgery. This study aimed to determine whether fibrosis scores calculated from non-invasive parameters are effective in monitoring liver function after bariatric surgery.

METHODS

This study analyzed data from 151 patients who underwent sleeve gastrectomy (SG) and were followed up at 3, 6, 9, 12, 24, and 36 months postoperatively. From the routinely collected parameters, liver fibrosis scores (APRI, Fib-4, BARD, Forns index [FORNS], Lok score [LOK], and NAFLD scores) were calculated retrospectively and compared to diabetes status % excess weight loss (%EWL) and % total weight loss (%TWL) over a 3-year follow-up period.

RESULTS

After SG, APRI, FORNS, and NAFLD scores showed significant improvements, whereas Fib-4, BARD, and LOK scores did not improve. Similarly, body mass index, %EWL, %TWL, and diabetes status also improved significantly. Throughout the 3-year follow-up period, only the APRI and NAFLD scores showed significant improvement.

CONCLUSION

Only APRI and NAFLD scores changed significantly after SG. Thus, these two scores may be used to reflect and monitor liver function in patients who have undergone SG.

Sleeve-gastrectomy results in improved metabolism and a massive stress response of the liver proteome in a mouse model of metabolic dysfunction-associated steatohepatitis

Background

Bariatric surgery has been shown to improve the histopathological findings in patients with obesity and metabolic dysfunction-associated steatohepatitis, but there are also reports about non-responders or progressive disease after bariatric interventions. Therefore, it is of utmost importance to understand the pathophysiological processes in the liver after bariatric surgery.

Materials and methods

In the present study, 4 weeks old male C57/Bl6 mice were fed a Western Diet to induce metabolic dysfunction-associated steatohepatitis and sleeve-gastrectomy (SG), or sham operation in the pair-fed and ad libitum control group were performed. Mice were observed for two or eight weeks after surgery and metabolic assessment was performed throughout the experiment. Histopathology, flow cytometry and proteomic analyses were conducted to evaluate hepatic inflammation, liver metabolism and affected signaling pathways.

Results

Weight loss was higher, and metabolism significantly improved after SG. Two weeks after SG major inflammatory and regulatory disturbances in the liver were observed. The proportion of hepatic CD3+NK1.1+ cells were decreased, and proteins involved in apoptosis like Fas, Casp1 and Casp9 or in the acute phase response were upregulated in SG mice. These disturbances decreased in the long-term and we observed an increase of many proteins involved in lipid metabolism eight weeks following SG.

Conclusions

The rapid weight loss and decrease of hepatic fat after SG lead to a proinflammatory response in the liver in the early phase after surgery, which changes to a more moderate immune response in the long-term. We suggest a preoperative risk stratification and postoperative surveillance depending on the histopathological findings.

Lithium toxicity following Roux-en-Y gastric bypass: Mini review and illustrative case

Lithium is among the mainstays of treatment for bipolar disorder. Bariatric surgery can considerably change the oral bioavailability of drugs, particularly lithium. In this review, a 36-year-old male patient is described, who presented with lithium toxicity, including neurologic and gastric symptoms after undergoing Roux-en-Y gastric bypass. The mechanism of lithium toxicity is discussed; recommendations for clinicians regarding lithium use in postsurgical patients are provided; and previous case reports of lithium toxicity post-gastric bypass surgery are analyzed. Awareness and education of lithium absorption changes postbariatric surgery is essential for optimal patient care. Close clinical and drug concentration level monitoring is warranted.

The LiMAx Test as Selection Criteria in Minimally Invasive Liver Surgery

BACKGROUND

Liver failure is a crucial predictor for relevant morbidity and mortality after hepatic surgery. Hence, a good patient selection is mandatory. We use the LiMAx test for patient selection for major or minor liver resections in robotic and laparoscopic liver surgery and share our experience here.

PATIENTS AND METHODS

We identified patients in the Magdeburg registry of minimally invasive liver surgery (MD-MILS) who underwent robotic or laparoscopic minor or major liver surgery and received a LiMAx test for preoperative evaluation of the liver function. This cohort was divided in two groups: patients with normal (LiMAx normal) and decreased (LiMAx decreased) liver function measured by the LiMAx test.

RESULTS

Forty patients were selected from the MD-MILS regarding the selection criteria (LiMAx normal, n = 22 and LiMAx decreased, n = 18). Significantly more major liver resections were performed in the LiMAx normal vs. the LiMAx decreased group (13 vs. 2; p = 0.003). Hence, the mean operation time was significantly longer in the LiMAx normal vs. the LiMAx decreased group (356.6 vs. 228.1 min; p = 0.003) and the intraoperative blood transfusion significantly higher in the LiMAx normal vs. the LiMAx decreased group (8 vs. 1; p = 0.027). There was no significant difference between the LiMAx groups regarding the length of hospital stay, intraoperative blood loss, liver surgery related morbidity or mortality, and resection margin status.

CONCLUSION

The LiMAx test is a helpful and reliable tool to precisely determine the liver function capacity. It aids in accurate patient selection for major or minor liver resections in minimally invasive liver surgery, which consequently serves to improve patients' safety. In this way, liver resections can be performed safely, even in patients with reduced liver function, without negatively affecting morbidity, mortality and the resection margin status, which is an important predictive oncological factor.

CT-Based Prediction of Liver Function and Post-PVE Hypertrophy Using an Artificial Neural Network

Background: This study aimed to evaluate whether hypertrophy after portal vein embolization (PVE) and maximum liver function capacity (LiMAx) are predictable by an artificial neural network (ANN) model based on computed tomography (CT) texture features. Methods: We report a retrospective analysis on 118 patients undergoing preoperative assessment by CT before and after PVE for subsequent extended liver resection due to a malignant tumor at RWTH Aachen University Hospital. The LiMAx test was carried out in a subgroup of 55 patients prior to PVE. Associations between CT texture features and hypertrophy as well as liver function were assessed by a multilayer perceptron ANN model. Results: Liver volumetry showed a median hypertrophy degree of 33.9% (16.5–60.4%) after PVE. Non-response, defined as a hypertrophy grade lower than 25%, was found in 36.5% (43/118) of the cases. The ANN prediction of the hypertrophy response showed a sensitivity of 95.8%, specificity of 44.4% and overall prediction accuracy of 74.6% (p < 0.001). The observed median LiMAx was 327 (248–433) μg/kg/h and was strongly correlated with the predicted LiMAx (R² = 0.89). Conclusion: Our study shows that an ANN model based on CT texture features is able to predict the maximum liver function capacity and may be useful to assess potential hypertrophy after performing PVE.

Comparison of Liver Recovery After Sleeve Gastrectomy and Roux-en-Y-Gastric Bypass

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a common condition in patients with obesity. Bariatric surgery has often been proposed as a viable treatment option, but the ideal surgical procedure remains unclear. Inconsistently, reports on postoperative deterioration of liver function put further doubt on which technique to apply. Aim of this study was to assess the impact of Roux-en-Y-gastric bypass (RYGB) and sleeve gastrectomy (SG) on the postoperative recovery of liver function.

METHODS

A total of 175 patients with obesity that underwent bariatric surgery in our institution were included in this prospective cohort study. BMI, laboratory values, and liver function capacity (using LiMAx) were assessed preoperatively and at 6 and 12 months postoperatively. Generalized linear model (GLM) was performed to determine variables influencing liver function capacity after the operation.

RESULTS

Prior to operations, 64% of patients presented with a diminished liver function capacity, as measured by LiMAx test. Liver function capacity significantly recovered after 12 months in the SG group (300 μg/kg/h preop vs. 367 μg/kg/h postop) but not in the RYGB group (306 μg/kg/h preop vs. 349 μg/kg/h). Preoperative factors impeding liver function recovery included type 2 diabetes mellitus (T2DM), weight, male sex, AST/thrombocyte ratio (APRI), and gamma-glutamyltransferase (GGT).

CONCLUSION

Bariatric surgery, especially sleeve gastrectomy, leads to an improvement of liver function. However, in some patients with T2DM, higher preoperative weight and male sex postoperative deterioration of liver function capacity may occur.

RYGB increases postprandial gastric nesfatin-1 and rapid relieves NAFLD via gastric nerve detachment

Background

Roux-en-Y gastric bypass (RYGB) could reduce nonalcoholic fatty liver disease (NAFLD) ahead of the weight-loss effects. But the detailed mechanisms remain unclear.

Material and methods

A high-fat diet (HFD) was fed to induce obesity. RYGB was then performed. Gastric nesfatin-1 was measured by enzyme-linked immunosorbent assay (ELISA) in portal vein and polymerase chain reaction (PCR) in gastric tissues. Modified surgeries including vagus-preserved bypass and vagectomy were performed and postprandial gastric nesfatin-1 were analyzed. The effects of nesfatin-1 on hepatocytes were studied by PCR and immunohistochemistry. Both intraperitoneal and intracerebroventricular injection (ICV) were performed to analyze the in vivo effects on liver lipid metabolism.

Results

Increased postprandial portal vein nesfatin-1 was observed in RYGB but not in control groups. This increase is mainly due to induction of gastric nesfatin-1. A modified RYGB in which the gastric vagus is preserved is conducted and, in this case, this nesfatin-1 induction effect is diminished. Mere vagectomy could also induce a similar nesfatin-1 increase pattern. The infusion of nesfatin-1 in the brain could inhibit the expression of gastric nesfatin-1, and the effects are diminished after gastric vagectomy. In vivo and in vitro nesfatin-1 stimulation in the liver resulted in improvements in lipid metabolism.

Conclusions

Severing the gastric vagus during RYGB could cut off the negative control from the central nervous system (CNS) and result in increased postprandial gastric nesfatin-1 post surgery, which in turn, improves NAFLD.

Baseline Presence of NAFLD Predicts Weight Loss after Gastric Bypass Surgery for Morbid Obesity

Background. Bariatric surgery is a widely used treatment for morbid obesity. Prediction of postoperative weight loss currently relies on prediction models, which mostly overestimate patients’ weight loss. Data about the influence of Non-alcoholic fatty liver disease (NAFLD) on early postoperative weight loss are scarce. Methods. This prospective, single-center cohort study included 143 patients receiving laparoscopic gastric bypass surgery (One Anastomosis-Mini Gastric Bypass (OAGB-MGB) or Roux-en-Y Gastric Bypass (RYGB)). Liver biopsies were acquired at surgery. NAFLD activity score (NAS) assigned patients to “No NAFLD”, “NAFL” or “NASH”. Follow up data were collected at 3, 6 and 12 months. Results. In total, 49.7% of patients had NASH, while 41.3% had NAFL. Compared with the No NAFLD group, NAFL and NASH showed higher body-mass-index (BMI) at follow-up (6 months: 31.0 kg/m² vs. 36.8 kg/m² and 36.1 kg/m², 12 months: 27.0 kg/m² vs. 34.4 and 32.8 kg/m²) and lower percentage of total body weight loss (%TBWL): (6 months: 27.1% vs. 23.3% and 24.4%; 12 months: 38.5% vs. 30.1 and 32.6%). Linear regression of NAS points significantly predicts percentage of excessive weight loss (%EWL) after 6 months (Cologne-weight-loss-prediction-score). Conclusions. Histopathological presence of NAFLD might lead to inferior postoperative weight reduction after gastric bypass surgery. The mechanisms underlying this observation should be further studied.

Evaluation of NAFLD and fibrosis in obese patients - a comparison of histological and clinical scoring systems

Background

Non-alcoholic fatty liver disease (NAFLD) is a frequent condition in obese patients and regularly progresses to non-alcoholic steatohepatitis (NASH) and subsequent cirrhosis. Histologic evaluation is the gold standard for grading and staging, but invasive biopsies are associated with obvious risks. The aim of this study was to evaluate different non-invasive tools for screening of NAFLD and fibrosis in obese patients.

Methods

In a prospective cohort study liver specimens of 141 patients were taken during bariatric surgery. Serological parameters and clinical data were collected and the following scores calculated: NASH clinical scoring system (NCS), aspartate aminotransferase to platelet ratio index (APRI), FIB-4 as well as NAFLD fibrosis score (NFS). Liver function capacity was measured preoperatively by LiMAx test (enzymatic capacity of cytochrome P450 1A2). Intraoperative liver biopsies were classified using NAFLD activity score (NAS) and steatosis, activity and fibrosis (SAF) score.

Results

APRI was able to differentiate between not NASH and definite NASH with a sensitivity of 74% and specificity of 67% (AUROC 0.76). LiMAx and NCS also showed significant differences between not NASH and definite NASH. No significant differences were found for NFS and Fib-4. APRI had a high sensitivity (83%) and specificity (76%) in distinguishing fibrosis from no fibrosis (AUROC = 0.81). NCS and Fib-4 also revealed high AUROCs (0.85 and 0.67), whereas LiMAx and NFS did not show statistically significant differences between fibrosis stages. Out of the patients with borderline NASH in the histologic NAS score, 48% were classified as NASH by SAF score.

Conclusions

APRI allows screening of NAFLD as well as fibrosis in obese patients. This score is easy to calculate and affordable, while conveniently only using routine clinical parameters. Using the NAS histologic scoring system bears the risk of underdiagnosing NASH in comparison to SAF score.

Assessing Non-Invasive Liver Function in Patients with Intestinal Failure Receiving Total Parenteral Nutrition-Results from the Prospective PNLiver Trial

Liver abnormalities in intestinal failure (IF) patients receiving parenteral nutrition (PN) can progress undetected by standard laboratory tests to intestinal failure associated liver disease (IFALD). The aim of this longitudinal study is to evaluate the ability of non-invasive liver function tests to assess liver function following the initiation of PN. Twenty adult patients with IF were prospectively included at PN initiation and received scheduled follow-up assessments after 6, 12, and 24 months between 2014 and 2019. Each visit included liver assessment (LiMAx [Liver Maximum Capacity] test, ICG [indocyanine green] test, FibroScan), laboratory tests (standard laboratory test, NAFLD [non-alcoholic fatty liver disease] score, FIB–4 [fibrosis-4] score), nutritional status (bioelectrical impedance analysis, indirect calorimetry), and quality of life assessment. The patients were categorized post-hoc based on their continuous need for PN into a reduced parenteral nutrition (RPN) group and a stable parenteral nutrition (SPN) group. While the SPN group (n = 9) had significantly shorter small bowel length and poorer nutritional status at baseline compared to the RPN group (n = 11), no difference in liver function was observed between the distinct groups. Over time, liver function determined by LiMAx did continuously decrease from baseline to 24 months in the SPN group but remained stable in the RPN group. This decrease in liver function assessed with LiMAx in the SPN group preceded deterioration of all other investigated liver function tests during the study period. Our results suggest that the liver function over time is primarily determined by the degree of intestinal failure. Furthermore, the LiMAx test appeared more sensitive in detecting early changes in liver function in comparison to other liver function tests.

Longitudinal Comparison of the Effect of Gastric Bypass to Sleeve Gastrectomy on Liver Function in a Bariatric Cohort: Tehran Obesity Treatment Study (TOTS)

BACKGROUND

Patients with morbid obesity commonly have fatty liver disease and elevated liver enzymes. While surgery effectively induces weight loss, bariatric techniques may differ regarding liver function improvement.

OBJECTIVES

To evaluate and compare the trends of liver function recovery after gastric bypass surgery (GB) with sleeve gastrectomy (SG).

SETTING

University hospitals, Iran.

METHODS

Adult bariatric candidates without a history of alcohol consumption or other etiologies of liver disease who underwent SG (n = 682) or GB (n = 355) were included. Trends of weight loss parameters and alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) at 0, 6 (in 90.4%), 12 (in 83.5%), and 24 months (in 67.1%) were compared using generalized estimating equations method.

RESULTS

Overall, 1037 patients with mean age of 38.4 ± 11.2 and mean body mass index of 44.9 ± 6.2 kg/m² were analyzed. Seventy-eight percent of patients had fatty liver by ultrasound. Both GB and SG patients lost significant weight, with GB patients having a higher percentage of excess weight loss at 24 months (80.1% vs. 75.9%, P_{between-group} = .008). SG patients showed more favorable trends in liver chemistries with significantly lower ALT at 12 months and AST and ALP levels at 6 and 12 months. However, the two groups were comparable at 24 months. Significantly more GB patients developed high ALT at 6 and high AST at 6 and 12 months. Undergoing GB was associated with smaller 0-12-month changes in ALT, AST, and ALP.

CONCLUSIONS

Bariatric surgery resulted in improvement in liver function parameters, with SG showing advantages over GB in the first postoperative year.

Short- and medium-term impact of bariatric surgery on the activities of CYP2D6, CYP3A4, CYP2C9, and CYP1A2 in morbid obesity

Morbid obesity and bariatric surgery induce anatomical, physiological and metabolic alterations that may alter the body’s disposition of drugs. Current literature on this topic is limited and sometimes inconsistent. Cytochrome P450 (CYP) is a superfamily of enzymes that metabolize around 75% of all marketed drugs. The purpose of this study was to evaluate the impact of body mass index and bariatric surgery on CYP activities. Firstly, we evaluated the in vivo activity of 4 major CYP isoenzymes (CYP2D6, CYP3A4, CYP2C9, and CYP1A2) in normal weight, overweight, and morbidly obese individuals. Secondly, we assessed the short- (1 month) and medium-term (6 month) effects of the most commonly employed bariatric surgery techniques (laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass) on the activity of these enzymes. CYP3A4 activity was lower in morbidly obese individuals, compared to normal-weight controls. Interestingly, bariatric surgery normalized CYP3A4 activity. In comparison with normal-weight controls, morbidly obese individuals had higher CYP2D6 activity, which was only observed in individuals with two functional alleles for this isoenzyme. Neither body mass index nor surgery had significant effects on CYP2C9 and CYP1A2 activities. Overall, no relevant differences in CYP activities were found between surgical techniques. In conclusion, further studies should evaluate whether the observed alterations in CYP3A4 activity will require dose adjustments for CYP3A4 substrates especially in morbidly obese individuals before and after bariatric surgery.

A retrospective case control study identifies peripheral blood mononuclear cell albumin RNA expression as a biomarker for non-alcoholic fatty liver disease

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) improves after bariatric surgery. The aim of this study was to determine whether peripheral blood mononuclear cell albumin gene expression was related to NAFLD and whether albumin (ALB) and alpha fetoprotein (AFP) expression could be detected in whole blood and visceral adipose tissue.

METHODS

Using a retrospective case control study design, RNA isolated from peripheral blood mononuclear cells from patients prior to undergoing bariatric surgery was used for pooled microarray analysis. Quantitative polymerase chain reaction (QPCR) was used to analyze whole blood and visceral adipose tissue. Liver histology was obtained via intra-operative biopsy and clinical data extracted from the electronic health record.

RESULTS

The albumin (ALB) gene was the second most up-regulated found in microarray analysis of peripheral blood mononuclear cell RNA from patients with hepatic lobular inflammation versus normal liver histology. Transcript levels of ALB were significantly different across those with normal (n = 50), steatosis (n = 50), lobular inflammation (n = 50), and peri-sinusoidal fibrosis (n = 50) liver histologies, with lobular inflammation 3.9 times higher than those with normal histology (p < 0.017). Albumin expression levels decreased in 11/13 patients in paired samples obtained prior to and at 1 year after Roux-en-Y gastric bypass surgery. ALB expression could be detected in 23 visceral adipose tissue samples obtained intra-operatively and in 18/19 available paired whole blood samples. No significant correlation was found between ALB expression in visceral adipose tissue and whole blood RNA samples. Alpha fetoprotein expression as a marker of early hepatocytic differentiation was detected in 17/17 available VAT RNA samples, but in only 2/17 whole blood RNA samples.

CONCLUSION

Albumin RNA expression from blood cells may serve as a biomarker of NAFLD. Albumin and alpha fetoprotein appear to be ubiquitously expressed in visceral adipose tissue in patients with extreme obesity.

Bariatric surgery in patients with non-alcoholic fatty liver disease - from pathophysiology to clinical effects

Non-alcoholic fatty liver disease (NAFLD) is increasingly recognized as a significant liver disease, and it covers the disease spectrum from simple steatosis with a risk of development of non-alcoholic steatohepatitis (NASH) to fibrosis, subsequent cirrhosis, end-stage liver failure, and liver cancer with a potential need for liver transplantation. NAFLD and NASH are closely related to obesity, metabolic syndrome, and type 2 diabetes (T2D). The role of gut hormones, especially glucagon-like peptide 1 (GLP-1), is important in NAFLD. Bariatric surgery has the potential for inducing great weight loss and may improve the symptoms of metabolic syndrome and T2D. Recent data demonstrated significant effects of bariatric surgery on GLP-1 and other gut hormones and important lipid metabolic and inflammatory abnormalities in the pathophysiology of NAFLD. Therefore, bariatric surgery may reverse the pathological liver changes in NAFLD and NASH patients. In the present review, we describe NAFLD and NASH pathophysiology and the primary effects of bariatric surgery on metabolic pathways. We performed a systematic review of the beneficial and harmful effects and focused on changes in liver disease severity in NAFLD and NASH patients. The specific focus was liver histopathology as assessed by the invasive liver biopsy. Additionally, we reviewed several non-invasive methods used for the assessment of liver disease severity following bariatric surgery.

Noninvasive Evaluation of Liver Function in Morbidly Obese Patients

Background

More than half of the obese patients develop nonalcoholic fatty liver disease (NAFLD), which may further progress to nonalcoholic steatohepatitis (NASH) and cirrhosis. The aim of this study was to assess alterations in liver function in obese patients with a noninvasive liver function test.

Methods

In a prospective cohort study 102 morbidly obese patients undergoing bariatric surgery were evaluated for their liver function. Liver function capacity was determined by the LiMAx® test (enzymatic capacity of cytochrome P450 1A2). Liver biopsy specimens were obtained intraoperatively and classified according to the NAFLD Activity Score (NAS). NASH clinical score was additionally calculated from laboratory and clinical parameters.

Results

Median liver function capacity was 286 (IQR = 141) μg/kg/h. 27% of patients were histologically categorized as definite NASH, 39% as borderline, and 34% as not NASH. A significant correlation was observed between liver function capacity and NAS (r = −0.492; p < 0.001). The sensitivity and specificity of the LiMAx® test to distinguish between definite NASH and not NASH were 85.2% and 82.9% (AUROC 0.859), respectively. According to the NASH clinical scoring system, 14% were classified as low risk, 31% as intermediate, 26% as high, and 29% as very high risk. Liver function capacity is also significantly correlated with the NASH clinical scoring system (r = −0.411; p < 0.001).

Conclusions

Obese patients show a diminished liver function capacity, especially those suffering from type 2 diabetes. The liver function capacity correlates with histological and clinical scoring systems. The LiMAx® test may be a valuable tool for noninvasive screening for NASH in obese patients.

Prospective Assessment of Liver Function by an Enzymatic Liver Function Test to Estimate Short-Term Survival in Patients with Liver Cirrhosis

BACKGROUND

MELD attempts to objectively predict the risk of mortality of patients with liver cirrhosis and is commonly used to prioritize organ allocation. Despite the usefulness of the MELD, updated metrics could further improve the accuracy of estimates of survival.

AIMS

To assess and compare the prognostic ability of an enzymatic ¹³C-based liver function test (LiMAx) and distinct markers of liver function to predict 3-month mortality of patients with chronic liver failure.

METHODS

We prospectively investigated liver function of 268 chronic liver failure patients without hepatocellular carcinoma. Primary study endpoint was liver-related death within 3 months of follow-up. Prognostic values were calculated using Cox proportional hazards and logistic regression analysis.

RESULTS

The Cox proportional hazard model indicated that LiMAx (p < 0.001) and serum creatinine values (p < 0.001) were the significant parameters independently associated with the risk of liver failure-related death. Logistic regression analysis revealed LiMAx and serum creatinine to be independent predictors of mortality. Areas under the receiver-operating characteristic curves for MELD (0.86 [0.80-0.92]) and for a combined score of LiMAx and serum creatinine (0.83 [0.76-0.90]) were comparable.

CONCLUSIONS

Apart from serum creatinine levels, enzymatic liver function measured by LiMAx was found to be an independent predictor of short-term mortality risk in patients with liver cirrhosis. A risk score combining both determinants allows reliable prediction of short-term prognosis considering actual organ function. Trial Registration Number (German Clinical Trials Register) # DRKS00000614.

Non-invasive Evaluation of NAFLD with Indocyanine Green Clearance Test: a Preliminary Study in Morbidly Obese Patients Undergoing Bariatric Surgery

BACKGROUND

Overweight and obesity dramatically increased in the last years. Hepatic complication of obesity, integrated in the term of non-alcoholic fatty liver disease (NAFLD), is a spectrum of abnormality ranging from steatosis to non-alcoholic steatohepatitis (NASH), potentially leading to cirrhosis. Liver biopsy remains the gold standard to evaluate the stage of NAFLD; however, the procedure is invasive. The indocyanine green (ICG) clearance test is performed since years to assess hepatic function before partial hepatectomy, or after liver transplantation. This study was designed to detect liver complications with the ICG clearance test in a population of obese patients scheduled for bariatric surgery.

METHODS

In a prospective cohort study, morbidly obese individuals receiving bariatric surgery with scheduled hepatic biopsies were investigated. Liver function was determined by the ICG test preoperatively, and blood samples were collected. Liver biopsy specimens were obtained for each patient and classified according to the NAFLD activity score (NAS) by a single pathologist that was blinded to the results of the ICG test.

RESULTS

Twenty-six patients were included (7 male and 19 female). The mean age of participants was 45.8 years; the mean body mass index was 41.4 kg/m². According to the NAS, 6 (23.1%) patients revealed manifest NASH, and 5 patients were considered borderline (19.2%). A closed correlation was observed between the ICG clearance test and hepatic steatosis (r = 0.43, p = 0.03), NAS (r = 0.44, p = 0.025), and fibrosis (r = 0.49, p = 0.01).

CONCLUSIONS

In obese patients, non-invasive evaluation of liver function with the indocyanine green clearance test correlated with histological features of NAFLD. This may detect non-invasively hepatopathy in obese population and could motive biopsy.

Long-Term Follow-Up Study of Liver-Related Outcome After Bilio-Pancreatic Diversion in Patients with Initial, Significant Liver Damage

BACKGROUND

Obesity is associated with NAFLD, and bariatric surgery has significant impact on this liver disease, with reported improvement in hepatic fibrosis.

AIMS

To investigate the effects of bariatric surgery on long-term liver disease-related outcome in obese patients with nonalcoholic fatty liver disease (NAFLD) and significant liver damage.

METHODS

This study included 56 NAFLD patients who underwent bilio-pancreatic diversion for morbid obesity and who had significant fibrosis at intraoperative liver biopsy. Data were analyzed at 1, 3, and 5 years of follow-up, and at the latest available visit in patients who had longer follow-up. We assessed the incidence of clinically relevant liver events (ascites, hepatic encephalopathy, portal hypertension-related bleeding, and jaundice) as well as modifications of a validated biochemical index such as the NAFLD score.

RESULTS

During a median follow-up of 78 months, median weight decreased from 119 to 78 kg (P < 0.0001), and median body mass index decreased from 45.2 to 29.0 kg/m² (P < 0.0001). None of the patients developed clinical complications of liver disease, and none died due to liver-related causes. Median NAFLD score significantly decreased (P = 0.0005) during follow-up from - 0.929 (- 1.543 to - 0.561) to - 1.609 (- 2.056 to - 1.102). The NAFLD score category was unchanged in 32 patients (57%), improved in 18 (32%), and worsened in 6 (11%).

CONCLUSIONS

Patients with NAFLD and proven histological liver damage at surgery do not develop complications of liver disease in long term after bilio-pancreatic diversion. Moreover, noninvasive parameters of liver damage improve. Thus, preexisting liver damage does not seem to be a contraindication to bilio-pancreatic diversion.

Impact of liver volume and liver function on posthepatectomy liver failure after portal vein embolization- A multivariable cohort analysis

BACKGROUND

Liver failure remains a life-threatening complication after liver resection, and is difficult to predict preoperatively. This retrospective cohort study evaluated different preoperative factors in regard to their impact on posthepatectomy liver failure (PHLF) after extended liver resection and previous portal vein embolization (PVE).

METHODS

Patient characteristics, liver function and liver volumes of patients undergoing PVE and subsequent liver resection were analyzed. Liver function was determined by the LiMAx test (enzymatic capacity of cytochrome P450 1A2). Factors associated with the primary end point PHLF (according to ISGLS definition) were identified through multivariable analysis. Secondary end points were 30-day mortality and morbidity.

RESULTS

95 patients received PVE, of which 64 patients underwent major liver resection. PHLF occurred in 7 patients (11%). Calculated postoperative liver function was significantly lower in patients with PHLF than in patients without PHLF (67 vs. 109 μg/kg/h; p = 0.01). Other factors associated with PHLF by univariable analysis were age, future liver remnant, MELD score, ASA score, renal insufficiency and heart insufficiency. By multivariable analysis, future liver remnant was the only factor significantly associated with PHLF (p = 0.03). Mortality and morbidity rates were 4.7% and 29.7% respectively.

CONCLUSION

Future liver remnant is the only preoperative factor with a significant impact on PHLF. Assessment of preoperative liver function may additionally help identify patients at risk for PHLF.

Effect of Weight Loss, Diet, Exercise, and Bariatric Surgery on Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. NAFLD is the most common liver disease in developed countries. Weight reduction of 3% to 5% is associated with improved steatosis; reductions of 5% to 7% are necessary for decreased inflammation; with 7% to 10%, individuals may experience NAFLD/NASH remission and regression of fibrosis. No specific dietary intervention has proven beneficial beyond calorie restriction. Physical activity without weight loss seems to decrease hepatic steatosis. Bariatric surgery is associated with decreased cardiovascular risk and improved overall mortality in addition to reduction in hepatic steatosis, inflammation, and fibrosis.

The importance of the Edmonton Obesity Staging System in predicting postoperative outcome and 30-day mortality after metabolic surgery

BACKGROUND

The Edmonton Obesity Staging System (EOSS) is a more comprehensive measure of obesity-related diseases and predictor of mortality than body mass index (BMI) or waist circumference. Its application for the selection of obese patients for obesity surgery has been suggested.

OBJECTIVES

The aim of this study was to determine whether the EOSS can also be used in predicting postoperative outcome and 30-day mortality after metabolic surgery.

SETTING

Center of maximum care in Germany METHODS: We collected data prospectively for patients undergoing laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-en-Y gastric bypass (LRYGB), or laparoscopic omega-loop gastric bypass (LOLGB). The data collected included preoperative EOSS score, gender, age, BMI, waist circumference, waist-to-hip ratio, co-morbidities, early postoperative complications, and 30-day mortality.

RESULTS

A total of 534 patients were included. The mean BMI was 45.57 kg/m² (range 35-64.5) for LRYGB patients (n = 168), 53.27 kg/m² (range 35.1-82.1) for LSG patients (n = 282), and 49.42 kg/m² (range 36-73.1) for LOLGB patients (n = 84). The total postoperative complication rate was 8.99%. The most common EOSS stage was 2 (70.6% of patients), followed by stages 3 (12.55%), 1 (11.61%), and 0 (5.06%). The postoperative complication rates after LRYGB, LSG, and LOLGB were 0% for EOSS 0 and 1.61% for EOSS 1. The postoperative complication rates were 8.22% for EOSS 2 and 22.39% for EOSS 3.

CONCLUSION

Patients with EOSS≥3 have a higher risk of postoperative complications. Our data confirm that the EOSS is useful as a scoring system for the selection of obese patients before surgery and suggest that it may also be useful for presurgical stratification and risk assessment in clinical practice. Patients should be recommended for obesity surgery when their EOSS stage is 2 to prevent impairments associated with metabolic disease and to reduce the risk of postoperative complications.

The Effect of Bariatric Surgery on the Spectrum of Fatty Liver Disease

Nonalcoholic fatty liver disease is becoming one of the most common causes of liver disease in the western world. The most significant risk factors are obesity and the metabolic syndrome for which bariatric surgery has been shown to be an effective treatment. However, the effects of bariatric surgery on nonalcoholic fatty liver disease, specifically liver fibrosis and cirrhosis, are not well established. We review published bariatric surgery outcomes with respect to nonalcoholic liver disease. On the basis of this review we suggest that bariatric surgery may provide a viable treatment option for the treatment of nonalcoholic fatty liver disease, including patients with fibrosis and compensated cirrhosis, and that this topic should be a target of future investigation.