Meta-analysis of randomized controlled trials on the effectiveness of somatostatin analogues for pancreatic surgery: a Cochrane review

BACKGROUND

The use of synthetic analogues of somatostatin following pancreatic surgery is controversial. The aim of this meta-analysis is to determine whether prophylactic somatostatin analogues (SAs) should be used routinely in pancreatic surgery.

METHODS

Randomized controlled trials were identified from the Cochrane Library Trials Register, MEDLINE, EMBASE, Science Citation Index Expanded and reference lists. Data were extracted from these trials by two independent reviewers. The risk ratio (RR), mean difference (MD) and standardized mean difference (SMD) were calculated with 95% confidence intervals (95% CIs) based on intention-to-treat or available case analysis.

RESULTS

Seventeen trials involving 2143 patients were identified. The overall number of patients with postoperative complications was lower in the SA group (RR 0.71, 95% CI 0.62-0.82), but there was no difference between the groups in perioperative mortality (RR 1.04, 95% CI 0.68-1.59), re-operation rate (RR 1.15, 95% CI 0.56-2.36) or hospital stay (MD -1.04 days, 95% CI -2.54 to 0.46). The incidence of pancreatic fistula was lower in the SA group (RR 0.64, 95% CI 0.53-0.78). The proportion of these fistulas that were clinically significant is not clear. Analysis of results of trials that clearly distinguished clinically significant fistulas revealed no difference between the two groups (RR 0.69, 95% CI 0.34-1.41). Subgroup analysis revealed a shorter hospital stay in the SA group than among controls for patients with malignant aetiology (MD -7.57 days, 95% CI -11.29 to -3.84).

CONCLUSIONS

Somatostatin analogues reduce perioperative complications but do not reduce perioperative mortality. However, they do shorten hospital stay in patients undergoing pancreatic surgery for malignancy. Further adequately powered trials of low risk of bias are necessary.

Miniport versus standard ports for laparoscopic cholecystectomy

BACKGROUND

In conventional (standard) laparoscopic cholecystectomy, four abdominal ports (two of 10 mm diameter and two of 5 mm diameter) are used. Recently, use of smaller ports have been reported.

OBJECTIVES

To assess the benefits and harms of miniport (defined as ports smaller than conventional ports) laparoscopic cholecystectomy versus standard laparoscopic cholecystectomy.

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 September 2009 for identifying the randomised trials.

SELECTION CRITERIA

Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing miniport versus standard ports laparoscopic cholecystectomy were considered for the review.

DATA COLLECTION AND ANALYSIS

Two authors collected the data independently. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI).

MAIN RESULTS

We included thirteen trials with 803 patients randomised to miniport (n = 416) versus standard ports laparoscopic cholecystectomy (n = 387). In twelve trials, four ports were used. In one trial, three ports were used. The bias risk of all trials was high. Miniport laparoscopic cholecystectomy could be completed successfully in 87% of patients. The remaining patients were mostly converted to standard laparoscopic cholecystectomy but some were also converted to open cholecystectomy. Further information about these patients who underwent conversion to open cholecystectomy was not available in most trials. In the patients on whom information was available, there was no mortality reported; and there was no significant difference in the surgery-related morbidity or conversion to open cholecystectomy. Most trials excluded the patients who were converted to standard laparoscopic cholecystectomy. In patients who underwent successful miniport laparoscopic cholecystectomy, the pain was significantly lower in the miniport group than in the standard port at various time points.

AUTHORS' CONCLUSIONS

Miniport laparoscopic cholecystectomy can be completed successfully in more than 85% of patients. Patients, in whom elective miniport laparoscopic cholecystectomy was completed successfully, had lower pain than those who underwent standard laparoscopic cholecystectomy. However, because of the lack of information on its safety, miniport laparoscopic cholecystectomy cannot be recommended outside well-designed, randomised clinical trials.

Meta-analysis of randomized controlled trials on the safety and effectiveness of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

The original article to which this Erratum refers was published in British Journal of Surgery 2010; 97: 141–150.

In vivo factors influencing tumour M2-pyruvate kinase level in human pancreatic cancer cell lines

In tumour cells, the tetramer/dimer ratio of the pyruvate kinase isoenzyme type M2 (M2-PK) determines whether glucose carbons are degraded to lactate with production of energy (tetrameric form) or are channelled into synthetic processes (dimeric form). The influence of different tumour microenvironment conditions on the tetramer/dimer ratio of M2-PK and cell doublings were investigated in a non-metastatic and metastatic pancreatic cancer cell line. The metastatic Colo357 cells contained about fourfold more M2-PK protein and about 3.5-fold more dimeric M2-PK than the non-metastatic Panc-1 cells. In Colo357 cells hypoxia, glucose starvation as well as acidification induced an increase of the dimeric form of M2-PK, whereas in Panc-1 cells no effect on M2-PK was observed. Under hypoxia in Colo357 cells, the dimerization and inactivation of M2-PK results in an inhibition of cell proliferation, whereas under glucose starvation and acidification the dimerization of M2-PK allowed further cell doublings. M2-PK expression and the quaternary structure of M2-PK are influenced by the tumour metastatic potential. The quaternary structure of M2-PK may be differently affected by hypoxia, glucose starvation and acidification with severe consequences on cell doublings.

Meta-analysis of randomized controlled trials on the safety and effectiveness of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

BACKGROUND

: In many countries laparoscopic cholecystectomy for acute cholecystitis is mainly performed after the acute episode has settled because of the anticipated increased risk of morbidity and higher conversion rate from laparoscopic to open cholecystectomy.

METHODS

: A systematic review was performed with meta-analysis of randomized clinical trials of early laparoscopic cholecystectomy (ELC; performed within 1 week of onset of symptoms) versus delayed laparoscopic cholecystectomy (performed at least 6 weeks after symptoms settled) for acute cholecystitis. Trials were identified from The Cochrane Library trials register, Medline, Embase, Science Citation Index Expanded and reference lists. Risk ratio (RR) or mean difference was calculated with 95 per cent confidence intervals (c.i.) based on intention-to-treat analysis.

RESULTS

: Five trials with 451 patients were included. There was no significant difference between the two groups in terms of bile duct injury (RR 0.64 (95 per cent c.i. 0.15 to 2.65)) or conversion to open cholecystectomy (RR 0.88 (95 per cent c.i. 0.62 to 1.25)). The total hospital stay was shorter by 4 days for ELC (mean difference -4.12 (95 per cent c.i. -5.22 to -3.03) days).

CONCLUSION

: ELC during acute cholecystitis appears safe and shortens the total hospital stay.

Cost-utility and value-of-information analysis of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

BACKGROUND

: A recent systematic review found early laparoscopic cholecystectomy (ELC) to be safe and to shorten total hospital stay compared with delayed laparoscopic cholecystectomy (DLC) for acute cholecystitis. The cost-effectiveness of ELC versus DLC for acute cholecystitis is unknown.

METHODS

: A decision tree model estimating and comparing costs to the UK National Health Service (NHS) and quality-adjusted life years (QALYs) gained following a policy of either ELC or DLC was developed with a time horizon of 1 year. Uncertainty was investigated with probabilistic sensitivity analysis, and value-of-information analysis estimated the likely return from further investment in research in this area.

RESULTS

: ELC is less costly (approximately - pound820 per patient) and results in better quality of life (+0.05 QALYs per patient) than DLC. Given a willingness-to-pay threshold of pound20 000 per QALY gained, there is a 70.9 per cent probability that ELC is cost effective compared with DLC. Full implementation of ELC could save the NHS pound8.5 million per annum.

CONCLUSION

: The results of this decision analytic modelling study suggest that on average ELC is less expensive and results in better quality of life than DLC. Future research should focus on quality-of-life measures alone.

Somatostatin analogues for pancreatic surgery

BACKGROUND

Pancreatic resections are associated with high morbidity (30% to 60%) and mortality (5%). Synthetic analogues of somatostatin are advocated by some surgeons to reduce complications following pancreatic surgery, however their use is controversial.

OBJECTIVES

To determine whether prophylactic somatostatin analogues should be used routinely in pancreatic surgery.

SEARCH STRATEGY

We searched the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 4), MEDLINE, EMBASE and Science Citation Index Expanded to November 2009.

SELECTION CRITERIA

We included randomised controlled trials comparing prophylactic somatostatin or one of its analogues versus no drug or placebo during pancreatic surgery (irrespective of language or publication status).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for inclusion and independently extracted data. We analysed data with both the fixed-effect and the random-effects models using Review Manager (RevMan). We calculated the risk ratio (RR), mean difference (MD) or standardised mean difference (SMD) with 95% confidence intervals (CI) based on an intention-to-treat or available case analysis. When it was not possible to perform either of the above, we performed per protocol analysis.

MAIN RESULTS

We identified 17 trials (of high risk of bias) involving 2143 patients. The overall number of patients with postoperative complications was lower in the somatostatin analogue group (RR 0.71; 95% CI 0.62 to 0.82) but there was no difference in the perioperative mortality, re-operation rate or hospital stay between the groups. The incidence of pancreatic fistula was lower in the somatostatin analogue group (RR 0.64; 95% CI 0.53 to 0.78). The proportion of these fistulas that were clinically significant was not mentioned in most trials. On inclusion of trials that clearly distinguished clinically significant fistulas, there was no difference between the two groups (RR 0.69; 95% CI 0.34 to 1.41). Subgroup analysis revealed a shorter hospital stay in the somatostatin analogue group than the controls for patients with malignant aetiology (MD -7.57; 95% CI -11.29 to -3.84).

AUTHORS' CONCLUSIONS

Somatostatin analogues reduce perioperative complications but do not reduce perioperative mortality. In those undergoing pancreatic surgery for malignancy, they shorten hospital stay. Further adequately powered trials with low risk of bias are necessary. Based on the current available evidence, somatostatin and its analogues are recommended for routine use in patients undergoing pancreatic resection for malignancy. There is currently no evidence to support their routine use in pancreatic surgeries performed for other indications.

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.

Antiviral therapy for recurrent liver graft infection with hepatitis C virus

BACKGROUND

Antiviral therapy to treat recurrent hepatitis C infection after liver transplantation is controversial due to unresolved balance between benefits and harms.

OBJECTIVES

To compare the therapeutic benefits and harms of different antiviral regimens in patients with hepatitis C re-infected grafts after liver transplantation.

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 March 2009.

SELECTION CRITERIA

Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing various antiviral therapies (alone or in combination) in the treatment of hepatitis C virus recurrence in liver transplantation were considered for the review.

DATA COLLECTION AND ANALYSIS

Two authors collected the data independently. We calculated the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) using the fixed-effect and the random-effects models based on available case-analysis. In the presence of only trial for a dichotomous outcome, we performed the Fisher's exact test.

MAIN RESULTS

A total of 425 liver transplant recipients with proven hepatitis C recurrence were randomised in twelve trials to various interventions and controls. The mean proportion of genotype I was 79.9% in the nine trials that reported the genotype. All the trials were of high risk of bias. One to two trials were included under each comparison including single drug or multidrug regimens of interferon, ribavirin, and amantadine. There was no significant difference in the mortality, graft rejection, or in re-transplantation between intervention and control in any of the comparisons that reported these outcomes. None of the trials reported liver decompensation or quality of life. Life-threatening adverse effects were not reported in either group in any of the comparisons. Up to 87.5% of patients required reduction in dose and up to 42.9% of patients required cessation of treatment in the various comparisons because of adverse effects or because of patient's choice to stop treatment.

AUTHORS' CONCLUSIONS

Considering the lack of clinical benefit and the frequent adverse effects, there is currently no evidence to recommend antiviral treatment for recurrent liver graft infection with HCV. Further randomised clinical trials with adequate trial methodology and adequate duration of follow-up are necessary.

Surgical resection versus non-surgical treatment for hepatic node positive patients with colorectal liver metastases

BACKGROUND

Involvement of hepatic lymph node in patients with colorectal liver metastases is associated with poor prognosis.

OBJECTIVES

To determine the benefits and harms of curative liver resection with lymphadenectomy versus other treatments for colorectal liver metastases with hepatic node involvement.

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, Science Citation Index Expanded, and LILACS until September 2009 for identifying the randomised trials.

SELECTION CRITERIA

We considered only randomised clinical trials (irrespective of language, blinding, or publication status) comparing liver resection (alone or in combination with radiofrequency ablation or cryoablation) versus other treatments (neo-adjuvant chemotherapy, chemotherapy, or radiofrequency ablation) in patients with colorectal liver metastases with hepatic node involvement.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion.

MAIN RESULTS

We were unable to identify any randomised clinical trial fulfilling the inclusion criteria of this review. We were also unable to identify any quasi-randomised or cohort studies, which could meaningfully answer this important issue.

AUTHORS' CONCLUSIONS

There is no evidence in the literature to assess the role of surgery versus other treatments for patients with colorectal liver metastases with hepatic node involvement. High quality randomised clinical trials are feasible and are necessary to determine the optimal management of patients with colorectal liver metastases with hepatic node involvement.

Design of surgical randomized controlled trials involving multiple interventions

BACKGROUND

Surgical trials evaluating multiple interventions can be carried out by using parallel or factorial trial design. The optimal trial method has not been established.

METHODS

Trials involving interventions to facilitate day-case laparoscopic cholecystectomy have been chosen to illustrate the strengths and weaknesses of these two trials designs.

RESULTS AND CONCLUSIONS

The parallel trial design is simple to design and interpret, but requires multiple randomized controlled trials to assess multiple interventions. It does not detect interactions between the interventions. Factorial trial design allows reduction in overall sample size and allows for exploration of interactions. However, it is not suitable when interventions are mutually exclusive, and it is associated with a higher risk of type I and type II statistical errors. Increased sample size is required in trials in which there are group interactions, which are present in a small proportion of the interventions. Both parallel trial design and factorial trial design have their advantages and disadvantages in the assessment of multiple interventions that can be applied in conjunction. Modifications to the factorial trial design appear to overcome many of the shortcomings of factorial trial design but require further increase in sample size to decrease type I and type II errors. In practice, the choice of trial design for multiple surgical interventions depends on the potential costs of type I and type II errors and the risk of missing important antagonistic and negative interactions.

Cardiopulmonary interventions to decrease blood loss and blood transfusion requirements for liver resection

BACKGROUND

Blood loss during liver resection is one of the most important factors affecting the peri-operative outcomes of patients undergoing liver resection.

OBJECTIVES

To determine the benefits and harms of cardiopulmonary interventions to decrease blood loss and to decrease allogeneic blood transfusion requirements in patients undergoing liver resections.

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 November 2008 for identifying the randomised trials.

SELECTION CRITERIA

We included all randomised clinical trials comparing various cardiopulmonary interventions aimed at decreasing blood loss and allogeneic blood transfusion requirements in liver resection. Trials were included irrespective of whether they included major or minor liver resections, normal or cirrhotic livers, vascular occlusion was used or not, and irrespective of the reason for liver resection.

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. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case-analysis. For dichotomous outcomes with only one trial included under the outcome, we performed the Fisher's exact test.

MAIN RESULTS

Nine trials involving 587 patients satisfied the inclusion criteria. The interventions included low central venous pressure (CVP), autologous blood donation, haemodilution, haemodilution with controlled hypotension, and hypoventilation. Only one or two trials were included under most comparisons. All trials had a high risk of bias. There was no significant difference in the peri-operative mortality or other peri-operative morbidity. None of the trials reported long-term survival or liver failure.The risk ratio of requiring allogeneic blood transfusion was significantly lower in the haemodilution and haemodilution with controlled hypotension groups than the respective control groups. Other interventions did not show significant decreases of allogeneic transfusion requirements.

AUTHORS' CONCLUSIONS

None of the interventions seem to decrease peri-operative morbidity or offer any long-term survival benefit. Haemodilution shows promise in the reduction of blood transfusion requirements in liver resection surgery. However, there is a high risk of type I (erroneously concluding that an intervention is beneficial when it is actually not beneficial) and type II errors (erroneously concluding that an intervention is not beneficial when it is actually beneficial) because of the few trials included, the small sample size in each trial, and the high risk of bias. Further randomised clinical trials with low risk of bias and random errors assessing clinically important outcomes such as peri-operative mortality are necessary to assess any cardiopulmonary interventions aimed at decreasing blood loss and blood transfusion requirements in liver resections. Trials need to be designed to assess the effect of a combination of different interventions in liver resections.

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 to decrease blood loss and blood transfusion requirements for liver resection

BACKGROUND

Blood loss during liver resection is one of the most important factors affecting the peri-operative outcomes of patients undergoing liver resection.

OBJECTIVES

To determine the benefits and harms of pharmacological interventions to decrease blood loss and to decrease allogeneic blood transfusion requirements in patients undergoing liver resections.

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 November 2008 for identifying the randomised trials.

SELECTION CRITERIA

We included all randomised clinical trials comparing various pharmacological interventions aimed at decreasing blood loss and allogeneic blood transfusion requirements in liver resection. Trials were included irrespective of whether they included major or minor liver resections, normal or cirrhotic livers, vascular occlusion was used or not, and irrespective of the reason for liver resection.

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. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference with 95% confidence intervals (CI) based on intention-to-treat analysis or available case-analysis. For dichotomous outcomes with only one trial included under the outcome, we performed the Fisher's exact test.

MAIN RESULTS

Six trials involving 849 patients satisfied the inclusion criteria. Pharmacological interventions included aprotinin, desmopressin, recombinant factor VIIa, antithrombin III, and tranexamic acid. One or two trials could be included under most comparisons. All trials had a high risk of bias. There was no significant difference in the peri-operative mortality, survival at maximal follow-up, liver failure, or other peri-operative morbidity. The risk ratio of requiring allogeneic blood transfusion was significantly lower in the aprotinin and tranexamic acid groups than the respective control groups. Other interventions did not show significant decreases of allogeneic transfusion requirements.

AUTHORS' CONCLUSIONS

None of the interventions seem to decrease peri-operative morbidity or offer any long-term survival benefit. Aprotinin and tranexamic acid show promise in the reduction of blood transfusion requirements in liver resection surgery. However, there is a high risk of type I (erroneously concluding that an intervention is beneficial when it is actually not beneficial) and type II errors (erroneously concluding that an intervention is not beneficial when it is actually beneficial) because of the few trials included, the small sample size in each trial, and the high risk of bias. Further randomised clinical trials with low risk of bias and random errors assessing clinically important outcomes such as peri-operative mortality are necessary to assess any pharmacological interventions aimed at decreasing blood loss and blood transfusion requirements in liver resections. Trials need to be designed to assess the effect of a combination of different interventions in liver resections.

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.

Multiple-approaches to the identification and quantification of cytochromes P450 in human liver tissue by mass spectrometry

Here we report the identification and approximate quantification of cytochrome P450 (CYP) proteins in human liver microsomes as determined by nano-LC-MS/MS with application of the exponentially modified protein abundance index (emPAI) algorithm during database searching. Protocols based on 1D-gel protein separation and 2D-LC peptide separation gave comparable results. In total, 18 CYP isoforms were unambiguously identified based on unique peptide matches. Further, we have determined the absolute quantity of two CYP enzymes (2E1 and 1A2) in human liver microsomes using stable-isotope dilution mass spectrometry, where microsomal proteins were separated by 1D-gel electrophoresis, digested with trypsin in the presence of either a CYP2E1- or 1A2-specific stable-isotope labeled tryptic peptide and analyzed by LC-MS/MS. Using multiple reaction monitoring (MRM) for the isotope-labeled tryptic peptides and their natural unlabeled analogues quantification could be performed over the range of 0.1-1.5 pmol on column. Liver microsomes from four individuals were analyzed for CYP2E1 giving values of 88-200 pmol/mg microsomal protein. The CYP1A2 content of microsomes from a further three individuals ranged from 165 to 263 pmol/mg microsomal protein. Although, in this proof-of-concept study for CYP quantification, the two CYP isoforms were quantified from different samples, there are no practical reasons to prevent multiplexing the method to allow the quantification of multiple CYP isoforms in a single sample.

Acute Limb Ischemia Caused by Femoral Arterial Line Induces Remote Liver Injury in a Rabbit Model of Liver Ischemia/Reperfusion Injury

Femoral arterial lines are used for continuous monitoring of arterial blood pressure in experimental studies. However, placement of a catheter in the femoral artery could produce acute limb ischemia with associated systemic effects. The aim of this study was to investigate the effect of femoral arterial line insertion on liver function, in a rabbit liver lobar ischemia-reperfusion (I/R) model. Four groups of animals (n = 6 each) were studied: groups 1 and 2 (sham) underwent laparotomy but no liver ischemia. In groups 3 and 4 (I/R), liver lobar ischemia was induced for 60 minutes followed by 7 hours of reperfusion. In groups 1 and 3, the arterial line was placed in the femoral artery whereas in groups 2 and 4 in the ear artery. Liver function was assessed by serum alanine aminotransferase (ALT) activity, bile flow, plasma lactate levels, and histology. Results are expressed as mean ± SEM. Alanine aminotransferase activity and lactate levels were significantly higher in the I/R femoral line group compared with the I/R ear line group at 7 hours postreperfusion. Bile production was significantly lower (75 ± 9.6 vs 112 ± 10 μL/min per 100 g liver weight). Histopathology showed more extensive hepatocellular necrosis and neutrophil accumulation in the I/R femoral line group compared with I/R ear line group. The sham femoral group showed liver injury, which was more marked than the ear line group (all P < .05). In conclusion, femoral artery cannulation induces remote liver injury. The use of femoral arterial lines should be avoided in experimental studies concerning liver function.

Techniques for liver parenchymal transection: a meta-analysis of randomized controlled trials

BACKGROUND

Different techniques of liver parenchymal transection have been described, including the finger fracture, sharp dissection, clamp-crush methods and, more recently, the Cavitron ultrasonic surgical aspirator (CUSA), the hydrojet and the radiofrequency dissection sealer (RFDS). This review assesses the benefits and risks associated with the various techniques.

METHODS

Randomized clinical trials were identified from the Cochrane Library Trials Register, MEDLINE, EMBASE, Science Citation Index Expanded and reference lists. Odds ratio (ORs), mean difference (MDs) and standardized mean differences (SMDs) were calculated with 95% confidence intervals based on intention-to-treat analysis or available-case analysis.

RESULTS

We identified seven trials including a total of 556 patients. Blood transfusion requirements were lower with the clamp-crush technique than with the CUSA or hydrojet. The clamp-crush technique was quicker than the CUSA, hydrojet or RFDS. Infective complications and transection blood loss were greater with the RFDS than with the clamp-crush method. There was no significant difference between techniques in mortality, morbidity, liver dysfunction or intensive therapy unit and hospital stay.

CONCLUSIONS

The clamp-crush technique is more rapid and is associated with lower rates of blood loss and otherwise similar outcomes when compared with other methods of parenchymal transection. It represents the reference standard against which new methods may be compared.

Bucillamine improves hepatic microcirculation and reduces hepatocellular injury after liver warm ischaemia-reperfusion injury

BACKGROUND

Liver transplantation and resection surgery involve a period of ischaemia and reperfusion to the liver which initiates an inflammatory cascade resulting in liver and remote organ injury. Bucillamine is a low-molecular-weight thiol antioxidant that is capable of rapidly entering cells.

METHODS

The effect of bucillamine was studied in a rat model of liver ischaemia-reperfusion injury with 45 min of partial (70%) liver ischaemia and at 3 and 24 h of reperfusion. Controls included ischaemia-reperfusion (I/R) only, sham and bucillamine alone (without ischaemia reperfusion). Liver injury was assessed by serum transaminases (AST and ALT). Sinusoidal blood flow and hepatocyte apoptosis were measured using intravital microscopy (IVM).

RESULTS

The hepatocellular injury of I/R produced a markedly elevated serum AST which was reduced with bucillamine (2072.5 +/- 511.79 vs. 932 +/- 200.8, P < 0.05) at 3 h reperfusion. Bucillamine treatment with I/R also increased parenchymal blood flow [red blood cell (RBC) velocity 242.66 +/- 16.86 vs. 181.11 +/- 17.59, at the end of 3 h of reperfusion) and reduced hepatocyte necrosis/apoptosis at 3 h as well as 24 h (P > 0.001).

CONCLUSION

Bucillamine reduces the hepatocellular injury of liver ischaemia reperfusion and improves parenchymal perfusion.

Liver resection versus other treatments for neuroendocrine tumours in patients with resectable liver metastases

BACKGROUND

Neuroendocrine tumours are tumours of cells, which possess secretory granules and originate from the neuroectoderm. While liver resection is generally advocated in patients with resectable liver metastases, recent studies have shown good survival in patients with disseminated neuroendocrine tumours who underwent thermal ablation using radiofrequency.

OBJECTIVES

To determine the benefits and harms of liver resection versus other treatments in patients with resectable liver metastases from gastro-entero-pancreatic neuroendocrine tumours.

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, Science Citation Index Expanded and LILACS until July 2008 for identifying the randomised trials.

SELECTION CRITERIA

We considered only randomised clinical trials (irrespective of language, blinding, or publication status) comparing liver resection (alone or in combination with radiofrequency ablation or cryoablation) versus other interventions (chemotherapy, hormonotherapy, or immunotherapy) and those comparing liver resection and thermal ablation (radiofrequency ablation or cryoablation) in patients with resectable liver metastases from neuroendocrine tumours for the review.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion.

MAIN RESULTS

We were unable to identify any randomised clinical trial suitable for inclusion in this review. We were also unable to identify any quasi-randomised studies, cohort studies, or case-control studies that could inform meaningfully.

AUTHORS' CONCLUSIONS

There is no evidence from randomised clinical trials comparing liver resection versus other treatments in patients with resectable liver metastases from gastro-entero-pancreatic neuroendocrine tumours. Liver resection appears to be the main stay curative treatment for neuroendocrine liver metastases based on non-randomised studies. Further randomised clinical trials comparing liver resection alone or in combination with chemoembolisation or radionuclide therapy are needed. Further randomised clinical trials comparing surgical resection and radiofrequency ablation in selected patients may also be appropriate.

Low pressure versus standard pressure pneumoperitoneum in laparoscopic cholecystectomy

BACKGROUND

A pneumoperitoneum of 12 to 16 mmHg is used for laparoscopic cholecystectomy. Lower pressures are claimed to be safe and effective in decreasing cardiopulmonary complications and pain.

OBJECTIVES

To assess the benefits and harms of low pressure pneumoperitoneum compared with standard pressure pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

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 November 2008 for identifying randomised trials using search strategies.

SELECTION CRITERIA

Only randomised clinical trials, irrespective of language, blinding, or publication status were considered for the review.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials and independently extracted data on mortality, morbidity, conversion to open cholecystectomy, pain, analgesic requirement, operating time, hospital stay, patient satisfaction, additional measures to increase vision, and cardiopulmonary parameters. We calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) using both the fixed-effect and the random-effects models with RevMan 5 based on available case-analysis.

MAIN RESULTS

Fifteen trials randomised 690 patients to low pressure (n = 336) and standard pressure (n = 354). All the trials were of high risk of bias. There was no difference in the mortality, morbidity, or conversion to open cholecystectomy between the groups. The intensity of pain was lower in the low pressure group at various time points. The incidence of shoulder pain was lower in the low pressure group (RR 0.53; 95% CI 0.31 to 0.90). The analgesic consumption was also lower. The operating time was similar between the groups (MD 2.30 minutes; 95% CI 0.42 to 4.18). Because of the high risk of bias due to incomplete outcome data in seven trials, it was not possible to conclude about the safety of low pressure pneumoperitoneum.

AUTHORS' CONCLUSIONS

Low pressure pneumoperitoneum appears effective in decreasing pain after laparoscopic cholecystectomy. The safety of low pressure pneumoperitoneum has to be established.