Modulation of microcirculatory changes in the late phase of hepatic ischaemia-reperfusion injury by remote ischaemic preconditioning

BACKGROUND

  Remote ischaemic preconditioning (RIPC) is a novel method of protecting the liver from ischaemia-reperfusion (I-R) injury. Protective effects in the early phase (4-6 h) have been demonstrated, but no studies have focused on the late phase (24 h) of hepatic I-R. This study analysed events in the late phase of I-R following RIPC and focused on the microcirculation, inflammatory cascade and the role of cytokine-induced neutrophil chemoattractant-1 (CINC-1).

METHODS

  A standard animal model was used. Remote preconditioning prior to I-R was induced by intermittent limb ischaemia. Ischaemia was induced in the left and median lobes of the liver (70%). The animals were recovered after 45 min of liver ischaemia. At 24 h, the animals were re-evaluated under anaesthesia. Hepatic microcirculation, sinusoidal leukocyte adherence and hepatocellular death were assessed by intravital microscopy, hepatocellular injury by standard biochemistry and serum CINC-1 by enzyme-linked immunosorbent assay (ELISA).

RESULTS

  At 24 h post I-R, RIPC was found to have improved sinusoidal flow by increasing the sinusoidal diameter. There was no effect of preconditioning on the velocity of red blood cells, by contrast with the early phase of hepatic I-R. Remote ischaemic preconditioning significantly reduced hepatocellular injury, neutrophil-induced endothelial injury and serum CINC-1 levels.

CONCLUSIONS

  Remote ischaemic preconditioning is amenable to translation into clinical practice and may improve outcomes in liver resection surgery and transplantation.

Intra-operative vs pre-operative endoscopic sphincterotomy in patients with gallbladder and common bile duct stones: cost-utility and value-of-information analysis

BACKGROUND

Patients with gallbladder and common bile duct stones are generally treated by pre-operative endoscopic sphincterotomy (ES) followed by laparoscopic cholecystectomy (POES). Recently, a meta-analysis has shown that intra-operative ES during laparoscopic cholecystectomy (IOES) results in fewer complications than POES, with similar efficacy. The cost effectiveness of IOES versus POES is unknown.

OBJECTIVE

The objective of this study was to compare the cost effectiveness of IOES versus POES from the UK NHS perspective.

METHODS

A decision-tree model estimating and comparing costs to the UK NHS and QALYs gained following a policy of either IOES or POES was developed with a time horizon of 3 years. Uncertainty was investigated with probabilistic sensitivity analysis, and the expected value of perfect information (EVPI) and partial information (EVPPI) were also calculated.

RESULTS

IOES was less costly than POES (approximately -£623 per patient [year 2008 values]) and resulted in similar quality of life (+0.008 QALYs per patient) as POES. Given a willingness-to-pay threshold of £20 000 per QALY gained, there was a 92.9% probability that IOES is cost effective compared with POES. Full implementation of IOES could save the NHS £2.8 million per annum. At a willingness to pay of £20 000 per QALY gained, the 10-year population EVPI was estimated at £0.6 million.

CONCLUSIONS

IOES appears to be cost effective compared with POES.

Methods to decrease blood loss and transfusion requirements for liver transplantation

BACKGROUND

Excessive blood loss and increased blood transfusion requirements may have significant impact on the short-term and long-term outcomes after liver transplantation.

OBJECTIVES

To compare the potential benefits and harms of different methods of decreasing blood loss and blood transfusion requirements during liver transplantation.

SEARCH METHODS

We searched The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and metaRegister of Controlled Trials until September 2011.

SELECTION CRITERIA

We included all randomised clinical trials that were performed to compare various methods of decreasing blood loss and blood transfusion requirements during liver transplantation.

DATA COLLECTION AND ANALYSIS

Two authors independently identified the trials and extracted the data. We analysed the data with both the fixed-effect and the random-effects model 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 available data analysis. We also conducted network meta-analysis.

MAIN RESULTS

We included 33 trials involving 1913 patients. The sample size in the trials varied from 8 to 209 participants. The interventions included pharmacological interventions (aprotinin, tranexamic acid, epsilon amino caproic acid, antithrombin 3, recombinant factor (rFvIIa), oestrogen, prostaglandin, epinephrine), blood substitutes (blood components rather than whole blood, hydroxy-ethyl starch, thromboelastography), and cardiovascular interventions (low central venous pressure). All the trials were of high risk of bias. Primary outcomes were reported in at least two trials for the following comparisons: aprotinin versus control, tranexamic acid versus control, recombinant factor VIIa (rFVIIa) versus control, and tranexamic acid versus aprotinin. There were no significant differences in the 60-day mortality (3 trials; 6/161 (3.7%) in the aprotinin group versus 8/119 (6.7%) in the control group; RR 0.52; 95% CI 0.18 to 1.45), primary graft non-function (2 trials; 0/128 (0.0%) in the aprotinin group versus 4/89 (4.5%) in the control group; RR 0.15; 95% CI 0.02 to 1.25), retransplantation (3 trials; 2/256 (0.8%) in the aprotinin group versus 12/178 (6.7%) in the control group; RR 0.21; 95% CI 0.02 to 1.79), or thromboembolic episodes (3 trials; 4/161 (2.5%) in the aprotinin group versus 5/119 (4.2%) in the control group; RR 0.59; 95% CI 0.19 to 1.84) between the aprotinin and control groups. There were no significant differences in the 60-day mortality (3 trials; 4/83 (4.8%) in the tranexamic acid group versus 5/56 (8.9%) in the control group; RR 0.55; 95% CI 0.17 to 1.76), retransplantation (2 trials; 3/41 (7.3%) in the tranexamic acid group versus 3/36 (8.3%) in the control group; RR 0.79; 95% CI 0.18 to 3.48), or thromboembolic episodes (5 trials; 5/103 (4.9%) in the tranexamic acid group versus 1/76 (1.3%) in the control group; RR 2.20; 95% CI 0.38 to 12.64) between the tranexamic acid and control groups. There were no significant differences in the 60-day mortality (3 trials; 8/195 (4.1%) in the recombinant factor VIIa (rFVIIa) group versus 2/91 (2.2%) in the control group; RR 1.51; 95% CI 0.33 to 6.95), thromboembolic episodes (2 trials; 24/185 (13.0%) in the rFVIIa group versus 8/81 (9.9%) in the control group; RR 1.38; 95% CI 0.65 to 2.91), or serious adverse events (2 trials; 90/185 (48.6%) in the rFVIIa group versus 30/81 (37.0%) in the control group; RR 1.30; 95% CI 0.94 to 1.78) between the rFVIIa and control groups. There were no significant differences in the 60-day mortality (2 trials; 6/91 (6.6%) in the tranexamic acid group versus 1/87 (1.1%) in the aprotinin group; RR 4.12; 95% CI 0.71 to 23.76) or thromboembolic episodes (2 trials; 4/91 (4.4%) in the tranexamic acid group versus 2/87 (2.3%) in the aprotinin group; RR 1.97; 95% CI 0.37 to 10.37) between the tranexamic acid and aprotinin groups. The remaining outcomes in the above comparisons and the remaining comparisons included only only trial under the primary outcome or the outcome was not reported at all in the trials. There were no significant differences in the mortality, primary graft non-function, graft failure, retransplantation, thromboembolic episodes, or serious adverse events in any of these comparisons. However, the confidence intervals were wide, and it is not possible to reach any conclusion on the safety of the interventions. None of the trials reported the quality of life in patients.Secondary outcomes were reported in at least two trials for the following comparisons - aprotinin versus control, tranexamic acid versus control, rFVIIa versus control, thromboelastography versus control, and tranexamic acid versus aprotinin. There was significantly lower allogeneic blood transfusion requirements in the aprotinin group than the control group (8 trials; 185 patients in aprotinin group and 190 patients in control group; SMD -0.61; 95% CI -0.82 to -0.40). There were no significant differences in the allogeneic blood transfusion requirements between the tranexamic acid and control groups (4 trials; 93 patients in tranexamic acid group and 66 patients in control group; SMD -0.27; 95% CI -0.59 to 0.06); rFVIIa and control groups (2 trials; 141 patients in rFVIIa group and 80 patients in control group; SMD -0.05; 95% CI -0.32 to 0.23); thromboelastography and control groups (2 trials; 31 patients in thromboelastography group and 31 patients in control group; SMD -0.73; 95% CI -1.69 to 0.24); or between the tranexamic acid and aprotinin groups (3 trials; 101 patients in tranexamic acid group and 97 patients in aprotinin group; SMD -0.09; 95% CI -0.36 to 0.19). The remaining outcomes in the above comparisons and the remaining comparisons included only only trial under the primary outcome or the outcome was not reported at all in the trials. There were no significant differences in the blood loss, transfusion requirements, hospital stay, or intensive care unit stay in most of the comparisons.

AUTHORS' CONCLUSIONS

Aprotinin, recombinant factor VIIa, and thromboelastography groups may potentially reduce blood loss and transfusion requirements. However, risks of systematic errors (bias) and risks of random errors (play of chance) hamper the confidence in this conclusion. We need further well-designed randomised trials with low risk of systematic error and low risk of random errors before these interventions can be supported or refuted.

Methods of decreasing infection to improve outcomes after liver resections

BACKGROUND

Infections cause both morbidity and mortality in patients undergoing liver resection. Various methods have been advocated to decrease the infectious complications after liver resection. We do not know if they are of any benefit to the patient or the health-care funder.

OBJECTIVES

To determine the benefits and harms of different interventions in decreasing the infectious complications and improving the outcomes after liver resection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until August 2011.

SELECTION CRITERIA

We included all randomised clinical trials that were performed to compare interventions aimed at decreasing the infectious complications after liver resection.

DATA COLLECTION AND ANALYSIS

Two authors independently identified the trials and extracted the data. We analysed the data with both the fixed-effect and the random-effects model using RevMan Analysis. For each outcome we calculated the risk ratio (RR), rate ratio, or mean difference (MD) with 95% confidence intervals (CI) based on available patient data analysis.

MAIN RESULTS

We included seven trials including 521 patients for this review. The sample size in the trials varied from 12 to 180 patients. All the trials were of high risks of systematic errors and of random errors. Four trials included patients who underwent liver resection only. In the remaining three trials, patients underwent combined liver resection with extrahepatic biliary resection resulting in a biliary enteric anastomosis. Four trials included only major liver resection. The remaining three trials included a mixture of major and minor liver resections. It appears that the proportion of cirrhotic patients in the trials was very low. The comparisons performed included whether antibiotics are necessary routinely during the peri-operative period of liver resection, the duration of antibiotics, the use of prebiotics and probiotics in the perioperative period, use of recombinant bactericidal-permeability increasing protein 21 (rBPI21), and the use of topical povidone iodine gel at the time of wound closure. Only one or two trials were included under each comparison. There was no significant differences in mortality or severe morbidity in any of the comparisons. Quality of life was not reported in any of the trials.

AUTHORS' CONCLUSIONS

There is currently no evidence to support or refute the use of any treatment to reduce infectious complications after liver resections. Further well designed trials with low risk of systematic error and low risk of random errors are necessary.

31-Phosphorus magnetic resonance spectroscopy for dynamic assessment of adenosine triphosphate levels in pancreas preserved by the two-layer method

Cold preservation injury influences islet graft function. Reliable tools for real-time assessment of pancreas viability before islet isolation are lacking. Phosphorus magnetic resonance spectroscopy ((31)P-MRS) was used immediately after organ harvest to study rat pancreases at 4 °C to 6 °C in five randomized preservation groups: Marshall's solution, static two-layer method (TLM), continuous TLM with oxygen perfused at 0.5 L/min, and static TLM or continuous TLM both the latter following 30 minutes of warm ischemia (WI). (31)P spectra were analyzed for phosphomonoesters, inorganic phosphate (Pi) and α-, β-and γ-nucleotide triphosphate. Intergroup rates of change of [γ-adenosine triphosphate (ATP)]/[Pi] and [β-ATP]/[Pi] throughout preservation period were significantly different. For continuous TLM there was an increase relative to baseline (0.043 (SD0.033) h(-1) and 0.029 (0.029) h(-1), respectively) but a decrease for both static TLM (-0.023 (0.016) h(-1) and 0.015 (0.026), P < .001 and < .05, respectively) and Marshall's (-0.049 (0.025) h(-1) and -0.036 (0.019) h(-1), respectively, both P < .001) with respect to continuous TLM. Rate of decrease was similar for the Marshall's and static TLM groups. [γ-ATP]/[Pi] and [β-ATP]/[Pi] increased with WI continuous TLM (0.008 [0.009] h(-1) and 0.007 [0.008] hr(-1), respectively) but decreased for WI static TLM (-0.018 (0.008) h(-1) and -0.014 (0.004) hr(-1), respectively, P < .001). (31)P-MRS is an effective tool for noninvasive assessment of pancreas bioenergetics. Continuous TLM preserves cellular bioenergetics and is superior to current non-perfluorocar bone based solutions for pancreas preservation.

Routine drainage for orthotopic liver transplantation

BACKGROUND

Routine use of abdominal drainage in patients undergoing liver transplantation is controversial.

OBJECTIVES

To assess the benefits and harms of routine abdominal drainage after orthotopic liver transplantation versus no drainage and to address different drain types.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and the MetaRegister of Controlled Trials until March 2011 to identify the randomised trials.

SELECTION CRITERIA

We planned to include only randomised clinical trials (irrespective of language, blinding, or publication status) addressing this issue.

DATA COLLECTION AND ANALYSIS

Two authors identified the trials for inclusion independently. Two authors planned to collect the data independently. We planned to analyse the data with both the fixed-effect and the random-effects model using RevMan Analysis. For each outcome we planned to calculate the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis whenever possible.

MAIN RESULTS

We did not identify any randomised clinical trials addressing this issue.

AUTHORS' CONCLUSIONS

There is currently no evidence to conclude whether routine abdominal drainage is useful or harmful in patients undergoing orthotopic liver transplantation. Evidence from non-randomised studies of high risk of bias showed conflicting results on the impact of routine drainage in orthotopic liver transplantation on serious adverse events, showing that this question is an important clinical research question. Well-designed randomised clinical trials with adequate sample size to decrease systematic errors and to decrease random errors are necessary.

Systematic review and meta-analysis of intraoperative versus preoperative endoscopic sphincterotomy in patients with gallbladder and suspected common bile duct stones

BACKGROUND

Most patients with gallbladder and common bile duct stones are treated by preoperative endoscopic sphincterotomy (POES) followed by laparoscopic cholecystectomy. Recently, intraoperative endoscopic sphincterotomy (IOES) during laparoscopic cholecystectomy has been suggested as an alternative treatment.

METHODS

Data from randomized clinical trials related to safety and effectiveness of IOES versus POES were extracted by two independent reviewers. Risk ratios (RRs) or mean differences were calculated with 95 per cent confidence intervals based on intention-to-treat analysis whenever possible.

RESULTS

Four trials with 532 patients comparing IOES with POES were included. There were no deaths. There was no significant difference in rates of ampullary cannulation (RR 1·01, 0·97 to 1·04; P = 0·70) or stone clearance by ES (RR 0·99, 0·96 to 1·02; P = 0·58) between the groups. The proportion of patients with at least one post-ES complication, including pancreatitis, bleeding, perforation, cholangitis, cholecystitis or gastric ulcer, was significantly lower in the IOES group (RR 0·37, 0·18 to 0·78; P = 0·009). There was no significant difference in morbidity after laparoscopic cholecystectomy or requirement for open operation between the groups. Mean hospital stay was 3 days shorter in the IOES group: mean difference - 2·83 (-3·66 to - 2·00) days (P < 0·001).

CONCLUSION

In patients with gallbladder and common bile duct stones, IOES is as effective and safe as POES and results in a significantly shorter hospital stay.

Elastography for the diagnosis of severity of fibrosis in chronic liver disease: a meta-analysis of diagnostic accuracy

BACKGROUND & AIMS

Transient elastography is a non-invasive method, for the assessment of hepatic fibrosis, developed as an alternative to liver biopsy. We studied the performance of elastography for diagnosis of fibrosis using meta-analysis.

METHODS

MEDLINE, EMBASE, SCI, Cochrane Library, conference abstracts books, and article references were searched. We included studies using biopsy as a reference standard, with the data necessary to calculate the true and false positive, true and false negative diagnostic results of elastography for a fibrosis stage, and with a 3-month maximum interval between tests. The quality of the studies was rated with the QUADAS tool.

RESULTS

We identified 40 eligible studies. Summary sensitivity and specificity was 0.79 (95% CI 0.74-0.82) and 0.78 (95% CI 0.72-0.83) for F2 stage and 0.83 (95% CI 0.79-0.86) and 0.89 (95% CI 0.87-0.91) for cirrhosis. After an elastography result at/over the threshold value for F2 or cirrhosis ("positive" result), the corresponding post-test probability for their presence (if pre-test probability was 50%) was 78%, and 88% respectively, while, if values were below these thresholds ("negative" result), the post-test probability was 21% and 16%, respectively. No optimal stiffness cut-offs for individual fibrosis stages were validated in independent cohorts and cut-offs had a wide range and overlap within and between stages.

CONCLUSIONS

Elastography theoretically has good sensitivity and specificity for cirrhosis (and less for lesser degrees of fibrosis); however, it should be cautiously applied to everyday clinical practice because there is no validation of the stiffness cut-offs for the various stages. Such validation is required before elastography is considered sufficiently accurate for non-invasive staging of fibrosis.

Veno-venous bypass versus none for liver transplantation

BACKGROUND

Veno-venous bypass is used to overcome the effects of clamping of the inferior vena cava and portal vein during liver transplanation. The routine use of veno-venous bypass is, however, controversial.

OBJECTIVES

To compare the benefits and harms of veno-venous bypass (irrespective of open or percutaneous technique; heparin-coated or no heparin-coating) versus no veno-venous bypass during liver transplantation. To compare the benefits and harms of the different techniques of veno-venous bypass during 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 December 2010.

SELECTION CRITERIA

We included randomised clinical trials comparing veno-venous bypass during liver transplantation (irrespective of language or publication status).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed 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 continuous outcomes, we calculated the mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat or available case analysis. For binary outcomes, we used the Fisher's exact test since none of the comparisons of binary outcomes included more than one trial.

MAIN RESULTS

We identified three trials with high risk of bias which compared veno-venous bypass (n = 65) versus no veno-venous bypass (n = 66). None of the trials reported patient or graft survival. There were no significant differences regarding renal failure or blood transfusion requirements between the two groups. None of the trials reported on the morbidity related to veno-venous bypass or the requirement of veno-venous bypass in the control group.We identified one trial with high risk of bias which compared percutaneous (n = 20) versus open technique (n =19) of veno-venous bypass. The patient or graft survival was not reported. There was no difference in veno-venous bypass related morbidity between the two groups. The operating time was significantly shorter in the percutaneous technique group (MD -59 minutes; 95% CI -102 to -16).

AUTHORS' CONCLUSIONS

There is no evidence to support or refute the use of veno-venous bypass in liver transplantation. There is no evidence to prefer any particular technique of veno-venous bypass in liver transplantation.

Three dimensional versus two dimensional imaging for laparoscopic cholecystectomy

BACKGROUND

The benefits and harms of three dimensional imaging versus traditional two dimensional imaging for laparoscopic cholecystectomy are not known.

OBJECTIVES

To assess the benefits and harms of use of three dimensional systems versus two dimensional systems during 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 October 2010 for randomised clinical trials.

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. We intended to calculate 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 intention-to-treat analysis.

MAIN RESULTS

One trial randomised 60 patients to three dimensional laparoscopic cholecystectomy (n = 30) versus standard two dimensional laparoscopic cholecystectomy (n = 30). This trial was of high risk of bias. There were no post-operative complications or conversion to open cholecystectomy in either group. There was no significant difference in the operating time (MD -1.00 minute; 95% CI -17.77 to 15.77) or number of errors between the two groups.

AUTHORS' CONCLUSIONS

Currently, there is no evidence that three dimensional image is superior to two dimensional image in laparoscopic cholecystectomy.

Piggy-back graft for liver transplantation

BACKGROUND

Piggy-back method of transplantation, which involves preservation of the recipient retrohepatic inferior vena cava, has been suggested as an alternative to the conventional method of liver transplantation, where the recipient retrohepatic inferior vena cava is resected.

OBJECTIVES

To compare the benefits and harms of piggy-back technique versus conventional liver transplantation as well as of the different modifications of piggy-back technique during 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 June 2010 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 (KSG and VP) independently identified trials and independently extracted data. We calculated the 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 intention-to-treat analysis for continuous outcomes. For binary outcomes, we used the Fisher's exact test since none of the comparisons of binary outcomes included more than one trial.

MAIN RESULTS

Two trials randomised in total 106 patients to piggy-back method (n = 53) versus conventional method with veno-venous bypass (n = 53). Both trials were at high risk of bias. There was no significant difference in post-operative mortality, primary graft non-function, vascular complications, renal failure, transfusion requirements, intensive therapy unit (ITU) stay, or hospital stay between the two groups. The warm ischaemic time was significantly shorter in the piggy-back method than the conventional method (MD -11.50 minutes; 95% CI -19.35 to -3.65; P < 0.01). The proportion of patients who developed chest complications were significantly higher in the the piggy-back method than the conventional method (75.8% versus 44.1%; P = 0.01).One trial randomised 80 patients to piggy-back with porto-caval bypass (n = 40) versus piggy-back without porto-caval bypass (n = 40). This trial was at high risk of bias. There was no significant difference in post-operative mortality, re-transplantation due to primary graft non-function, vascular complications, renal failure, or hospital stay between the two groups. Fewer patients required blood transfusion in the piggy-back with porto-caval bypass group (55%) than the piggy-back without porto-caval bypass group (75%) (P = 0.02). There was no significant difference in the mean amount of blood transfused between the groups (MD -1.00 unit; 95% CI -2.19 to 0.19; P = 0.10). The ITU stay was significantly shorter in the piggy-back with porto-caval bypass group (2.9 days) than the piggy-back without porto-caval bypass group (4.9 days; MD -2.00 days; 95% CI -3.82 to -0.18; P = 0.03).There were no trials comparing piggy-back method with conventional method without veno-venous bypass or different techniques of piggy-back method.

AUTHORS' CONCLUSIONS

There is currently no evidence to recommend or refute the use of piggy-back method of liver transplantation.

Risk factors associated with early hepatic artery thrombosis after orthotopic liver transplantation - univariable and multivariable analysis

Hepatic artery thrombosis (HAT) is a serious complication in patients undergoing orthotopic liver transplantation (OLT). It is associated with a high graft loss and mortality rate. In this study, possible risk factors associated with early HAT (occurring within the first postoperative month) were evaluated using univariable and multivariable analyses. Nine-hundred-and-fourteen consecutive OLTs in our institution were examined by univariable and multivariable analyses. Early HAT occurred in 43 patients (4.7%). Graft number, abnormal donor arterial anatomy, bench arterial reconstruction, aortic conduit use, multiple anastomoses, reperfusion time (interval between portal vein reperfusion and restoration of arterial flow) and the number of units of blood received intraoperatively were significantly associated with early HAT in the univariable analysis(P<0.1). These variables were included in a multivariable regression model which showed that bench arterial reconstruction was associated with a fourfold risk of early HAT(P<0.0001), whereas each additional 10min delay in reperfusion was associated with a 27% increase in the risk of early HAT (P<0.04). The main risk factors associated with early HAT are abnormal arterial anatomy in the graft requiring bench reconstruction and a delay in arterial reperfusion. Early recognition of these factors, strict surveillance protocols with arterial Doppler and selective anticoagulation for patients at risk need to be evaluated prospectively.

R0 but not R1/R2 resection is associated with better survival than palliative photodynamic therapy in biliary tract cancer

BACKGROUND

There is a need for better management strategies to improve the survival and quality of life in patients with biliary tract cancer (BTC).

AIM

To assess prognostic factors for survival in a large, non-selective cohort of patients with BTC.

METHOD

We compared outcomes in 321 patients with a final diagnosis of BTC (cholangiocarcinoma n = 237, gallbladder cancer n = 84) seen in a tertiary referral cancer centre between 1998 and 2007. Survival according to disease stage and treatment category was compared using log-rank testing. Cox's regression analysis was used to determine independent prognostic factors.

RESULTS

Eighty-nine (28%) patients underwent a surgical intervention with curative intent, of whom 38% had R0 resections. Among the 321 patients, 34% were given chemo- and/or radiotherapy, 14% were palliated with photodynamic therapy (PDT) and 37% with biliary drainage procedures alone. The overall median survival was 9 months (3-year survival, 14%). R0-resective surgery conferred the most favourable outcome (3-year survival, 57%). Although patients palliated with PDT had more advanced clinical T-stages, their survival was similar to those treated with attempted curative surgery but who had positive resection margins. On multivariable analysis, treatment modality, serum carbohydrate-associated antigen 19-9, distant metastases and vascular involvement were independent prognostic indicators of survival.

CONCLUSION

In this large UK series of BTC, palliative PDT resulted in survival similar to those with curatively intended R1/R2 resections. Surgery conferred a survival advantage only in patients with R0 resection margins, emphasising the need for accurate pre-operative staging.

Glycine maintains mitochondrial activity and bile composition following warm liver ischemia-reperfusion injury

BACKGROUND AND AIM

Experimental studies have shown protective effect by the non-essential amino acid glycine to liver ischemia-reperfusion (I/R) injury but the mechanism of action is unknown.

METHODS

A rabbit model of hepatic lobar I/R was used. Three groups of animals (n=6) were studied: Sham group (laparotomy alone), ischemia reperfusion (I/R) group (1 h of liver lobar ischemia and 6 h of reperfusion), and a glycine I/R group (intravenous glycine 5 mg/kg prior to the I/R protocol). Systemic and hepatic hemodynamics, degree of liver injury (bile flow, transaminases), hepatic microcirculation, mitochondrial activity (redox state of cytochrome oxidase), bile composition and cytokines (tumor necrosis factor-α and interleukin-8) were measured during the experiment.

RESULTS

Glycine administration increased portal blood flow, bile production, hepatic microcirculation and maintained cytochrome oxidase activity as compared with the I/R group during reperfusion. Glycine also reduced bile lactate surge and stimulated acetoacetate release in bile during reperfusion versus the I/R group. Cytokine levels (tumor necrosis factor-α, interleukin-8) and hepatocellular injury (aspartate aminotransferase and alanine aminotransferase) were significantly reduced by glycine administration.

CONCLUSION

Intravenous glycine administration reduces liver warm I/R injury by reducing the systemic inflammatory response, and maintaining cellular energy production.

Effect of remote ischemic preconditioning on liver ischemia/reperfusion injury using a new mouse model

Ischemic preconditioning of remote organs (RIPC) reduces liver ischemia/reperfusion (IR) injury in the rabbit and rat. Mice are the only species available with a large number of transgenic strains. This study describes development and validation of a mouse model of hindlimb RIPC that attenuates liver IR injury. Mice were allocated to 4 groups: (1) Sham surgery; (2) RIPC: 6 cycles of 4 × 4 minutes ischemia/reperfusion of hindlimb; (3) IR: 40 minutes lobar (70%) hepatic ischemia and 2 hours reperfusion; (4) RIPC+IR: RIPC followed by IR group procedures. Plasma liver aminotransferases and hepatic histopathological and transmission electron microscopy studies were performed at the end of the experiment. Hepatic microcirculatory blood flow was measured throughout the experiment. Postoperative complications and animal survival were evaluated. Hindlimb RIPC using a tourniquet resulted in limb paralysis. Hindlimb RIPC using direct clamping of the femoral vessels showed no side effects. Compared to liver IR alone, RIPC+IR reduced plasma aminotransferases (P < 0.05) and histopathological and ultrastructural features of injury. Hepatic microcirculatory blood flow was preserved in the RIPC+IR compared to IR group (P < 0.05). There was no mortality in any of the groups. By demonstrating a consistent improvement in these features of liver IR injury with antecedent hindlimb RIPC and by minimizing experimental confounding variables, we validated this mouse model. In conclusion, we describe a validated mouse model of hindlimb RIPC that reduces liver IR injury. With the availability of transgenic mice strains, this model should prove useful in unraveling the mechanisms of protection of hindlimb RIPC.

Current protective strategies in liver surgery

During liver resection surgery for cancer or liver transplantation, the liver is subject to ischaemia (reduction in blood flow) followed by reperfusion (restoration of blood flow), which results in liver injury [ischemia-reperfusion (IR) or IR injury]. Modulation of IR injury can be achieved in various ways. These include hypothermia, ischaemic preconditioning (IPC) (brief cycles of ischaemia followed by reperfusion of the organ before the prolonged period of ischaemia i.e. a conditioning response), ischaemic postconditioning (conditioning after the prolonged period of ischaemia but before the reperfusion), pharmacological agents to decrease IR injury, genetic modulation of IR injury, and machine perfusion (pulsatile perfusion). Hypothermia decreases the metabolic functions and the oxygen consumption of organs. Static cold storage in University of Wisconsin solution reduces IR injury and has prolonged organ storage and improved the function of transplanted grafts. There is currently no evidence for any clinical advantage in the use of alternate solutions for static cold storage. Although experimental data from animal models suggest that IPC, ischaemic postconditioning, various pharmacological agents, gene therapy, and machine perfusion decrease IR injury, none of these interventions can be recommended in clinical practice. This is because of the lack of randomized controlled trials assessing the safety and efficacy of ischaemic postconditioning, gene therapy, and machine perfusion. Randomized controlled trials and systematic reviews of randomized controlled trials assessing the safety and efficacy of IPC and various pharmacological agents have demonstrated biochemical or histological improvements but this has not translated to clinical benefit. Further well designed randomized controlled trials are necessary to assess the various new protective strategies in liver resection.

Antiviral prophylactic intervention for chronic hepatitis C virus in patients undergoing liver transplantation

BACKGROUND

It is not clear whether prophylactic antiviral therapy is indicated in patients undergoing liver transplantation for chronic decompensated hepatitis C virus (HCV) infection.

OBJECTIVES

To compare the benefits and harms of different prophylactic anti-viral therapies for patients undergoing liver transplantation for chronic HCV infection.

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 August 2010.

SELECTION CRITERIA

Only randomised clinical trials irrespective of language, blinding, or publication status and comparing various prophylactic antiviral therapies (alone or in combination) in the prophylactic treatment of patients undergoing liver transplantation for chronic HCV infection.

DATA COLLECTION AND ANALYSIS

Two authors collected the data independently. We calculated the risk ratio (RR) or mean difference (MD) or hazard ratio (HR) with 95% confidence intervals (CI) using the fixed-effect and the random-effects models based on available case analysis.

MAIN RESULTS

A total of 477 liver transplant recipients undergoing liver transplantation for chronic HCV infection were randomised in eleven trials to various interventions and controls. The proportion of genotype I varied between 49% to 88% in the five trials that reported the genotype. Only one or two trials were included under each comparison. All the trials were of high risk of bias. There was no significant differences in the patient survival, graft rejection, re-transplantation, or HCV recurrence between intervention and control groups in any of the comparisons that reported these outcomes. None of the trials reported liver decompensation, primary graft non-function, intensive therapy unit stay, hospital stay, or quality of life. Life-threatening adverse events were not reported in either group in any of the comparisons. Up to 91% of patients required reduction in dose and up to 36% of patients required cessation of treatment in the various comparisons because of adverse events or because of patient's choice to stop treatment.

AUTHORS' CONCLUSIONS

There is currently no evidence to recommend prophylactic antiviral treatment to prevent recurrence of HCV infection either in primary liver transplantation or re-transplantation. Further randomised clinical trials with adequate trial methodology and adequate duration of follow-up are necessary.

Attenuation of warm ischemia-reperfusion injury in the liver by bucillamine through decreased neutrophil activation and Bax/Bcl-2 modulation

BACKGROUND AND AIM

Liver transplantation and resection surgery involve a period of ischemia 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. We hypothesized that bucillamine acts by replenishing glutathione levels, thus reducing neutrophil activation, modulating Bax/Bcl-2 expression, and subsequently, attenuating the effects of warm ischemia-reperfusion injury (IRI) in the liver.

METHODS

The effect of bucillamine was studied in a rat model of liver IRI with 45 min of partial (70%) liver ischemia and 3 h of reperfusion. Liver injury was assessed by measuring serum transaminases (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) and liver histology. Oxidative stress was quantified by measuring F(2) isoprostane and glutathione levels. Leukocyte adhesion was assessed by intravital microscopy, and inflammatory cytokine response was assessed by measuring serum cytokine-induced neutrophil chemoattractant-1 (CINC-1) levels. Bax and Bcl-2 expression was measured by reverse transcription-polymerase chain reaction.

RESULTS

The model produced significant liver injury with elevated transaminases and an acute inflammatory response. Bucillamine reduced the liver injury, as indicated by reduced AST (932 ± 200.8 vs 2072.5 ± 511.79, P < 0.05). Bucillamine reduced Bax expression, serum CINC-1 levels, and neutrophil adhesion, and upregulated Bcl-2. However, bucillamine did not affect tissue glutathione levels nor the levels of oxidative stress, as measured by plasma and hepatic F(2) isoprostane levels.

CONCLUSIONS

Bucillamine reduces warm ischemia-reperfusion in the liver by inhibiting neutrophil activation and modulating Bax/Bcl-2 expression.

Methods of cystic duct occlusion during laparoscopic cholecystectomy

BACKGROUND

During laparoscopic cholecystectomy, it is necessary to occlude the cystic duct permanently. Traditionally, this has been performed through the application of non-absorbable metal clips. Use of absorbable materials to occlude the cystic duct has been suggested as an alternative for metal clips for various reasons.

OBJECTIVES

To assess the benefits and harms of the different methods of occlusion of cystic duct in patients undergoing laparoscopic cholecystectomy.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until August 2010.

SELECTION CRITERIA

We included all randomised clinical trials comparing different methods of occlusion of cystic duct.

DATA COLLECTION AND ANALYSIS

We collected the data on the characteristics, methodological quality, bile duct injury, bile leaks, operating time, and incidence of recurrent common bile duct stone from each trial. We analysed the data with both the fixed-effect and the random-effects model using RevMan Analysis. For each outcome we calculated the risk ratio (RR) in the presence of more than one trial for the outcome or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis. In the presence of only one trial under a dichotomous outcome, we performed the Fisher's exact test.

MAIN RESULTS

Three trials including 255 patients qualified for this review. In two of the trial, a total of 150 patients were randomised to absorbable clips (n = 75) and non-absorbable clips (n = 75). In the third trial, a total of 105 patients were randomised to absorbable ligatures (n = 53) and non-absorbable clips (n = 52). All three trials were of high risk of bias. There was no difference in the morbidity between the groups. There was statistically significant longer operating time (MD 12.00 minutes, 95% CI 1.59 to 22.41) in the absorbable ligature group than non-absorbable clips. The duration and method of follow-up were not adequate to determine the incidence of long-term complications.

AUTHORS' CONCLUSIONS

We are unable to determine the benefits and harms of different methods of cystic duct occlusion because of the small sample size, short period of follow-up, and lack of reporting of important outcomes in the included trials. Adequately powered randomised trials with low risk of bias and with long periods of follow-up and assessing all of the important outcomes for patients and professionals are necessary.

Prophylactic gastrojejunostomy for unresectable periampullary carcinoma

BACKGROUND

The role of prophylactic gastrojejunostomy in patients with unresectable periampullary cancer is controversial.

OBJECTIVES

To determine whether prophylactic gastrojejunostomy should be performed routinely in patients with unresectable periampullary cancer.

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 2010, issue 3), MEDLINE, EMBASE and Science Citation Index Expanded until April 2010.

SELECTION CRITERIA

We included randomised controlled trials comparing prophylactic gastrojejunostomy versus no gastrojejunostomy in patients with unresectable periampullary cancer (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 hazard ratio (HR), risk ratio (RR), or mean difference (MD) with 95% confidence intervals (CI) based on an intention-to-treat or available case analysis.

MAIN RESULTS

We identified two trials (of high risk of bias) involving 152 patients randomised to gastrojejunostomy (80 patients) and no gastrojejunostomy (72 patients). In both trials, patients were found to be unresectable during exploratory laparotomy. Most of the patients also underwent biliary-enteric drainage. There was no evidence of difference in the overall survival (HR 1.02; 95% CI 0.84 to 1.25), peri-operative mortality or morbidity, quality of life, or hospital stay (MD 0.97 days; 95%CI -0.18 to 2.12) between the two groups. The proportion of patients who developed long term gastric outlet obstruction was significantly lower in the prophylactic gastrojejunostomy group (2/80; 2.5%) compared with no gastrojejunostomy group (20/72; 27.8%) (RR 0.10; 95%CI 0.03 to 0.37). The operating time was significantly longer in the gastrojejunostomy group compared with no gastrojejunostomy group (MD 45.00 minutes; 95%CI 21.39 to 68.61).

AUTHORS' CONCLUSIONS

Routine prophylactic gastrojejunostomy is indicated in patients with unresectable periampullary cancer undergoing exploratory laparotomy (with or without hepaticojejunostomy).