Hepatic protection by perioperative metabolic support?

Impact of body mass index on postoperative outcomes in patients undergoing radical resection for hilar cholangiocarcinoma

BACKGROUND

Body mass index (BMI) has been widely used as a prognostic indicator. The association between preoperative BMI and postoperative morbidity in patients with hilar cholangiocarcinoma (HCCA) has not been proved. This study aimed to identify the association between preoperative BMI and postoperative morbidity following radical resection of HCCA.

METHODS

Patients were divided into three groups according to preoperative BMI: low BMI (≤18.4 kg/m² ), normal BMI (18.4-24.9 kg/m² ), and high BMI (≥24.9 kg/m² ). Baseline characteristics, operative variables, postoperative 30-day mortality, and morbidity were compared. Risk factors associated with postoperative morbidity were assessed using univariable and multivariable logistic analyses.

RESULTS

Among 260 patients, 183 (70.4%) had normal BMI, 32 (12.3%) had low BMI, and 45 (17.3%) had high BMI. Compared to the patients with normal-BMI, both low and high BMI patients exhibited a significantly higher postoperative morbidity (87.5% and 82.2% vs 63.9%, P = .019 and P = .025, respectively). Additionally, the multivariable analysis revealed that both low and high BMI patients remained independently associated with an increased risk of postoperative morbidity. (OR: 3.707, 95% CI: 1.080-12.725, P = .037; and OR: 2.858, 95% CI: 1.167-7.002, P = .022, respectively).

CONCLUSION

BMI is an independent risk factor for higher postoperative morbidity in patients who undergo surgical treatment of hilar cholangiocarcinoma.

Nutrition and metabolism in hepatocellular carcinoma

Hepatocellular carcinoma is the fifth most common human cancer worldwide, with an overall 5-year survival in the range of 10%. In addition to the very substantial role of chronic viral hepatitis in causing hepatocellular carcinoma, nutritional status and specific nutritional factors appear to influence disease risk. This is apparent in the increased risk associated with non-alcoholic hepatic cirrhosis occurring in the context of obesity, the metabolic syndrome, and type 2 diabetes. Specific nutrients and ingested toxins, including ethanol, aflatoxin, microcystins, iron, and possibly components of red meat, also are associated with increased hepatocellular carcinoma risk. Other dietary components, including omega-3 fatty acids and branched chain amino acids, may have protective effects. Recent data further suggest that several metabolic regulatory drugs, including metformin, pioglitazone, and statins, may have the potential to decrease the risk of hepatocellular carcinoma. The available data on these nutritional and metabolic factors in causing hepatocellular carcinoma are reviewed with the goal of identifying the strength of current knowledge and directions for future investigation.

Randomized clinical trial of the impact of insulin therapy on liver function in patients undergoing major liver resection

BACKGROUND

Postoperative liver dysfunction is the major source of morbidity and mortality in patients undergoing partial hepatectomy. This study tested the benefits of a metabolic support protocol based on insulin infusion, for reducing liver dysfunction following hepatic resection.

METHODS

Consecutive consenting patients scheduled for liver resection were randomized to receive preoperative dextrose infusion followed by insulin therapy using the hyperinsulinaemic normoglycaemic clamp protocol (n = 29) or standard therapy (control group, n = 27). Patients in the insulin therapy group followed a strict dietary regimen for 24 h before surgery. Intravenous dextrose was started at 2 mg per kg per min the night before and continued until surgery. Hyperinsulinaemic therapy for a total of 24 h was initiated at 2 munits per kg per min at induction of anaesthesia, and continued at 1 munit per kg per min after surgery. Normoglycaemia was maintained (3.5-6.0 mmol/l). Control subjects received no additional dietary supplement and a conventional insulin sliding scale during fasting. All patients were tested serially to evaluate liver function using the Schindl score. Liver tissue samples were collected at two time points during surgery to measure glycogen levels.

RESULTS

Demographics were similar in the two groups. More liver dysfunction occurred in the control cohort (liver dysfunction score range 0-8 versus 0-4 with insulin therapy; P = 0.031). Median (interquartile range) liver glycogen content was 278 (153-312) and 431 (334-459) µmol/g respectively (P = 0.011). The number of complications rose with increasing severity of postoperative liver dysfunction (P = 0.032) CONCLUSION: The glucose-insulin protocol reduced postoperative liver dysfunction and improved liver glycogen content.

REGISTRATION NUMBER

NCT00774098 (http://www.clinicaltrials.gov).

Parenteral nutrition in liver resection

Albeit a very large number of experiments have assessed the impact of various substrates on liver regeneration after partial hepatectomy, a limited number of clinical studies have evaluated artificial nutrition in liver resection patients. This is a peculiar topic because many patients do not need artificial nutrition, while several patients need it because of malnutrition and/or prolonged inability to feeding caused by complications. The optimal nutritional regimen to support liver regeneration, within other postoperative problems or complications, is not yet exactly defined. This short review addresses relevant aspects and potential developments in the issue of postoperative parenteral nutrition after liver resection.

Nutritional aspects in patient undergoing liver resection

In the past two decades, hepatic surgery has achieved important technical breakthroughs resulting in a drastic reduction of the onset of complications and in an improved post-resective survival. Pre-operative nutritional status is one of the key points for the success of a liver resection. Modern surgical achievement such as the development of living-related liver donation, and the possibility to perform more laparoscopic liver resection gave us the opportunity to extend post-operative protocol focused on early intestinal feeding to tumor patients. The aims of this review were to report the current status of the knowledge regarding nutritional aspects in liver resection patients.

Systematic review of randomized controlled trials of pharmacological interventions to reduce ischaemia-reperfusion injury in elective liver resection with vascular occlusion

BACKGROUND

Vascular occlusion during liver resection results in ischaemia-reperfusion (IR) injury, which can lead to liver dysfunction. We performed a systematic review and meta-analysis to assess the benefits and harms of using various pharmacological agents to decrease IR injury during liver resection with vascular occlusion.

METHODS

Randomized clinical trials (RCTs) evaluating pharmacological agents in liver resections conducted under vascular occlusion were identified. Two independent reviewers extracted data on population characteristics and risk of bias in the trials, and on outcomes such as postoperative morbidity, hospital stay and liver function.

RESULTS

A total of 18 RCTs evaluating 17 different pharmacological interventions were identified. There was no significant difference in perioperative mortality, liver failure or postoperative morbidity between the intervention and control groups in any of the comparisons. A significant improvement in liver function was seen with methylprednisolone use. Hospital and intensive therapy unit stay were significantly shortened with trimetazidine and vitamin E use, respectively. Markers of liver parenchymal injury were significantly lower in the methylprednisolone, trimetazidine, dextrose and ulinastatin groups compared with their respective controls (placebo or no intervention).

DISCUSSION

Methylprednisolone, trimetazidine, dextrose and ulinastatin may have protective roles against IR injury in liver resection. However, based on the current evidence, they cannot be recommended for routine use and their application should be restricted to RCTs.

Three targets of branched-chain amino acid supplementation in the treatment of liver disease

The article explains the pathogenesis of disturbances in branched-chain amino acid (BCAA; valine, leucine, and isoleucine) and protein metabolism in various forms of hepatic injury and it is suggested that the main cause of decrease in plasma BCAA concentration in liver cirrhosis is hyperammonemia. Three possible targets of BCAA supplementation in hepatic disease are suggested: (1) hepatic encephalopathy, (2) liver regeneration, and (3) hepatic cachexia. The BCAA may ameliorate hepatic encephalopathy by promoting ammonia detoxification, correction of the plasma amino acid imbalance, and by reduced brain influx of aromatic amino acids. The influence of BCAA supplementation on hepatic encephalopathy could be more effective in chronic hepatic injury with hyperammonemia and low concentrations of BCAA in blood than in acute hepatic illness, where hyperaminoacidemia frequently develops. The favorable effect of BCAA on liver regeneration and nutritional state of the body is related to their stimulatory effect on protein synthesis, secretion of hepatocyte growth factor, glutamine production and inhibitory effect on proteolysis. Presumably the beneficial effect of BCAA on hepatic cachexia is significant in compensated liver disease with decreased plasma BCAA concentrations, whereas it is less pronounced in hepatic diseases with inflammatory complications and enhanced protein turnover. It is concluded that specific benefits associated with BCAA supplementation depend significantly on the type of liver disease and on the presence of inflammatory reaction. An important task for clinical research is to identify groups of patients for whom BCAA treatment can significantly improve the health-related quality of life and the prognosis of hepatic disease.

Hyperglycemia during hepatic resection: continuous monitoring of blood glucose concentration

BACKGROUND AND AIMS

This study assessed glucose metabolism via continuous intraoperative monitoring of blood glucose in patients undergoing hepatic resection.

METHODS

Thirty patients who underwent hepatic resection were enrolled. During hepatic resection, blood glucose concentration was continuously measured by an artificial pancreas.

RESULTS

Glucose concentrations followed a similar up-and-down pattern in all patients during the Pringle maneuver series. The concentration decreased marginally during the first clamping of the hepatoduodenal ligament but showed a rapid increase after unclamping. However, this increase declined with the number of Pringle cycles (P < .01). Patients with liver cirrhosis showed smaller elevations in glucose concentration after the first unclamping compared with patients without liver cirrhosis (P < .05).

CONCLUSIONS

The present study showed a rapid and profound transition in glucose concentration during hepatic resection. The mechanism underlying the transition of blood glucose concentration may involve glycogen break down within hepatocytes because of hypoxia.

Pharmacological interventions versus no pharmacological intervention for ischaemia reperfusion injury in liver resection surgery performed under vascular control

BACKGROUND

Vascular occlusion to reduce blood loss is used during elective liver resection but results in significant ischaemia reperfusion injury. This, in turn, might lead to significant postoperative liver dysfunction and morbidity. Various pharmacological drugs have been used with an intention to ameliorate the ischaemia reperfusion injury in liver resections.

OBJECTIVES

To assess the benefits and harms of different pharmacological agents versus no pharmacological interventions to decrease ischaemia reperfusion injury during liver resections where vascular occlusion was performed during the surgery.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2009.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of language or publication status, comparing any pharmacological agent versus placebo or no pharmacological agent during elective liver resections with vascular occlusion.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted the data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. We calculated the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis.

MAIN RESULTS

We identified a total of 15 randomised trials evaluating 11 different pharmacological interventions (methylprednisolone, multivitamin antioxidant infusion, vitamin E infusion, amrinone, prostaglandin E1, pentoxifylline, mannitol, trimetazidine, dextrose, allopurinol, and OKY 046 (a thromboxane A2 synthetase inhibitor)). All trials had high risk of bias. There were no significant differences between the groups in mortality, liver failure, or perioperative morbidity. The trimetazidine group had a significantly shorter hospital stay than control (MD -3.00 days; 95% CI -3.57 to -2.43). There were no significant differences in any of the clinically relevant outcomes in the remaining comparisons. Methylprednisolone improved the enzyme markers of liver function and trimetazidine, methylprednisolone, and dextrose reduced the enzyme markers of liver injury compared with controls. However, there is a high risk of type I and type II errors because of the few trials included, the small sample size in each trial, and the risk of bias.

AUTHORS' CONCLUSIONS

Trimetazidine, methylprednisolone, and dextrose may protect against ischaemia reperfusion injury in elective liver resections performed under vascular occlusion, but this is shown in trials with small sample sizes and high risk of bias. The use of these drugs should be restricted to well-designed randomised clinical trials before implementing them in clinical practice.

Pharmacological interventions for ischaemia reperfusion injury in liver resection surgery performed under vascular control

BACKGROUND

Vascular occlusion used during elective liver resection to reduce blood loss results in significant ischaemia reperfusion (IR) injury. This in turn leads to significant postoperative liver dysfunction and morbidity. Various pharmacological drugs have been used in experimental settings to ameliorate the ischaemia reperfusion injury in liver resections.

OBJECTIVES

To assess the relative benefits and harms of using one pharmacological intervention versus another pharmacological intervention to decrease ischaemia reperfusion injury during liver resections where vascular occlusion was performed during the surgery.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2009.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of language or publication status, comparing one pharmacological agent versus another pharmacological agent during elective liver resections with vascular occlusion.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. We planned to calculate the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis. However, all outcomes were only reported on by single trials, and meta-analysis could not be performed. Therefore, we performed Fisher's exact test on dichotomous outcomes.

MAIN RESULTS

We identified a total of five randomised trials evaluating nine different pharmacological interventions (amrinone, prostaglandin E1, pentoxifylline, dopexamine, dopamine, ulinastatin, gantaile, sevoflurane, and propofol). All trials had high risk of bias. There was no significant difference between the groups in mortality, liver failure, or perioperative morbidity. The ulinastatin group had significantly lower postoperative enzyme markers of liver injury compared with the gantaile group. None of the other comparisons showed any difference in any of the other outcomes. However, there is a high risk of type I and type II errors because of the few trials included, the small sample size in each trial, and the risk of bias.

AUTHORS' CONCLUSIONS

Ulinastatin may have a protective effect against ischaemia reperfusion injury relative to gantaile in elective liver resections performed under vascular occlusion. The absolute benefit of this drug agent remains unknown. None of the drugs can be recommended for routine clinical practice. Considering that none of the drugs have proven to be useful to decrease ischaemia reperfusion injury, such trials should include a group of patients who do not receive any active intervention whenever possible to determine the pharmacological drug's absolute effects on ischaemia reperfusion injury in liver resections.

Discipline-specific insulin sensitivity in athletes

OBJECTIVE

Weight status and abnormal liver function are the two factors that influence whole-body insulin sensitivity. The main goal of the study was to compare insulin sensitivity in athletes (n=757) and physically active controls (n=670) in relation to the two factors.

METHODS

Homeostatic metabolic assessment for insulin resistance (HOMA-IR), weight status, and abnormal liver function (alanine aminotransferase and aspartate aminotransferase) were determined from 33 sports disciplines under morning fasted condition. This study was initiated in autumn 2006 and repeated in autumn 2007 (n=1508) to ensure consistency of all observations.

RESULTS

In general, HOMA-IR and blood pressure levels in athletes were significantly greater than those in physically active controls but varied widely with sport disciplines. Rowing and short-distance track athletes had significantly lower HOMA-IR values and archery and field-throwing athletes had significantly higher values than the control group. Intriguingly, athletes from 22 sports disciplines displayed significantly greater body mass index values above control values. Multiple regression analysis showed that, for non-athlete controls, body mass index was the only factor that contributed to the variations in HOMA-IR. For athletes, body mass index and alanine aminotransferase independently contributed to the variation of HOMA-IR.

CONCLUSION

This is the first report documenting HOMA-IR values in athletes from a broad range of sport disciplines. Weight status and abnormal liver function levels appear to be the major contributors predicting insulin sensitivity for the physically active population.