Effects of hepatovenous back flow on ischemic- reperfusion injuries in liver resections with the pringle maneuver

A randomized porcine study of the hemodynamic and metabolic effects of combined endovascular occlusion of the vena cava and the aorta in normovolemia and in hemorrhagic shock

BACKGROUND

Mortality from traumatic retrohepatic venous injuries is high and methods for temporary circulatory stabilization are needed. We investigated survival and hemodynamic and metabolic effects of resuscitative endovascular balloon occlusion of the aorta (REBOA) and vena cava inferior (REBOVC) in anesthetized pigs.

METHODS

Twenty-five anesthetized pigs in normovolemia or severe hemorrhagic shock (controlled arterial bleeding in blood bags targeting systolic arterial pressure of 50 mm Hg, corresponding to 40-50% of the blood volume) were randomized to REBOA zone 1 or REBOA+REBOVC zone 1 (n = 6-7/group) for 45 minutes occlusion, followed by 3-hour resuscitation and reperfusion. Hemodynamic and metabolic variables and markers of end-organ damage were measured regularly.

RESULTS

During occlusion, both the REBOA groups had higher systemic mean arterial pressure (MAP) and cardiac output (p < 0.05) compared with the two REBOA+REBOVC groups. After 60 minutes reperfusion, there were no statistically significant differences between the two REBOA groups and the two REBOA+REBOVC groups in MAP and cardiac output. The two REBOA+REBOVC groups had higher arterial lactate and potassium concentrations during reperfusion, compared with the two REBOA groups (p < 0.05). There was no major difference in end-organ damage markers between REBOA and REBOA+REBOVC. Survival after 1-hour reperfusion was 86% and 100%, respectively, in the normovolemic REBOA and REBOA+REBOVC groups, and 67% and 83%, respectively, in the corresponding hemorrhagic shock REBOA and REBOA+REBOVC groups.

CONCLUSION

Acceptable hemodynamic stability during occlusion and short-term survival can be achieved by REBOA+REBOVC with adequate resuscitation; however, the more severe hemodynamic and metabolic impacts of REBOA+REBOVC compared with REBOA must be considered.

LEVEL OF EVIDENCE

Prospective, randomized, experimental animal study. Basic science study, therapeutic.

Blood flow of the venous system during resuscitative endovascular balloon occlusion of the aorta: Noninvasive evaluation using phase contrast magnetic resonance imaging

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a viable resuscitation approach for a subdiaphragmatic injury that can regulate arterial blood flow. On the other hand, the evaluation of venous or portal venous blood flow during REBOA remains insufficient because invasive cannulation or exposure of the vessel may affect the blood flow, and Doppler echography is highly operator-dependent. However, phase contrast magnetic resonance imaging has enabled accurate evaluation and noninvasive measurement. This study aimed to investigate the change of venous and portal venous blood flow during REBOA in a porcine model.

METHODS

Seven pigs were anesthetized, and a REBOA catheter was placed. The blood flows of the inferior vena cava (IVC), hepatic vein (HV), portal vein (PV), and superior vena cava (SVC) were measured using phase contrast magnetic resonance imaging, in both the balloon deflated (no-REBOA) and fully balloon inflated (REBOA) states. Mean arterial pressure (MAP), central venous pressure, cardiac index, and systemic vascular resistance index were measured.

RESULTS

The blood flows of the suprahepatic, infrahepatic, and distal IVC, HV, and PV in the no-REBOA state were 1.40 ± 0.36 L·min, 0.94 ± 0.16 L·min, 0.50 ± 0.19 L·min, 0.060 ± 0.018 L·min, and 0.32 ± 0.091 L·min, respectively. The blood flow of each section in the REBOA condition was significantly decreased at 0.41 ± 0.078 (33% of baseline), 0.15 ± 0.13 (15%), 0.043 ± 0.034 (9%), 0.029 ± 0.017 (37%), and 0.070 ± 0.034 L·min (21%), respectively. The blood flow of the SVC increased significantly in the REBOA condition (1.4 ± 0.63 L·min vs. 0.53 ± 0.14 L·min [257%]). Mean arterial pressure, central venous pressure, cardiac index, and systemic vascular resistance index were significantly increased after REBOA inflation.

CONCLUSION

Resuscitative endovascular balloon occlusion of the aorta decreased blood flows of the IVC, HV, and PV and increased blood flow of the SVC. This result could be explained by the collateral flow from the lower body to the SVC. A better understanding of the effect of REBOA on the venous and portal venous systems may help control liver injury.

Effect of the intermittent Pringle maneuver on liver damage after hepatectomy: a retrospective cohort study

Background

The Pringle maneuver (PM) interrupts the blood flow through the hepatic artery and portal vein to help control bleeding. This study analyzes the effects of the intermittent Pringle maneuver (IPM) on the surgical process and postoperative liver injury.

Methods

This study retrospectively evaluated 182 hepatocellular carcinoma patients who underwent hepatectomy. In the IPM group, hepatic blood flow was intermittently interrupted via clamping, with cycles of 10 minutes of inflow occlusion followed by 5 minutes of reperfusion that were repeated until the end of the surgery. In the non-IPM group, liver resection was performed without hepatic vascular blockage.

Results

For postoperative complications, the incidence rates of ascites and pleural effusion in the IPM group were significantly lower than those in the non-IPM group. The postoperative hospitalization time in the IPM group was significantly lower than that in the non-IPM group (p=0.0008). On the first day after the operation, the platelet count was significantly lower (p=0.0381) but the prothrombin time (PT) (p=0.0195) and activated partial thromboplastin time (APTT) (p=0.0071) were significantly higher in the non-IPM group than those in the IPM group. At discharge, only albumin was significantly higher in the non-IPM group than that in the IPM group (p=0.0303). Regression analysis showed that a prolonged interruption time was related to increased ALT and AST levels on the first day after surgery, but not on the seventh day or at discharge.

Conclusion

The IPM does not cause additional liver damage during hepatectomy, and use of the IPM results in shorter hospital stays compared to surgery without using the IPM. The results of this study require further confirmation because of the retrospective design.

Electronic supplementary material

The online version of this article (10.1186/s12957-019-1680-y) contains supplementary material, which is available to authorized users.

Laparoscopic liver hanging maneuver through the retrohepatic tunnel on the right side of the inferior vena cava combined with a simple vascular occlusion technique for laparoscopic right hemihepatectomy

Background

Laparoscopic hepatectomy has been performed in many hospitals, with the development of the laparoscopic operation technique. However, performing complex laparoscopic hepatectomy, such as right hemihepatectomy, is still a challenge. The aim of this study was to describe the application of a simple vascular occlusion technique and new liver hanging maneuver (LHM) in complex laparoscopic hepatectomy, which are both advocated by Chen Xiaoping for open hepatectomy.

Methods

The clinical data of 29 consecutive patients who underwent laparoscopic right hemihepatectomy (LRH) from October 2014 to October 2016 were retrospectively analyzed. During operation, the vascular occlusion technique without hilus dissection and LHM through the retrohepatic avascular tunnel on the right side of the inferior vena cava were used.

Result

All 29 operations were successfully performed laparoscopically, while adopting Chen’s methods. The study consisted of 23 patients with hepatocellular carcinoma, four patients with intrahepatic cholangiocarcinoma, and two patients with hepatic metastasis of colonic carcinoma. The tumor size was 12.4 ± 1.9 cm. The operation time of LRH was 190.3 ± 49.9 min. The intraoperative blood loss of LRH was 281.7 ± 117.8 mL; five patients required blood transfusion, and the amount of blood transfusion was 300.0 ± 89.4 mL. No case was converted to open surgery, and no death occurred. All resulted in R0 resections. The median free margin was 20.1 ± 10.8 mm. The time of postoperative oral diet intake was 2.10 ± 0.96 days. The complication rate was 17.2%. The average hospital stay after operation was 10.0 ± 2.9 days.

Conclusion

Complex hepatectomy is a bloodless procedure that can be performed under a laparoscope safely using Chen’s methods of vascular occlusion technique and LHM.

Personalized stepwise vascular control during complex hepatectomy involving hepatocaval confluence

BACKGROUND

This study introduces an innovative stepwise vascular control technique to address the high risk of massive bleeding from main hepatic veins and the retro-hepatic inferior vena cava during hepatectomy involving hepatocaval confluence.

METHODS

From January 2010 to July 2016, 80 patients underwent stepwise vascular occlusion during complex liver resection involving hepatocaval confluence. Relevant clinical data were collected and compared with those obtained in parallel studies. The protocol has been registered in the Protocol Registration and Results System as protocol NCT02996006.

RESULTS

All 80 patients underwent portal triad (PT), infra-hepatic inferior vena cava (IIVC) and supra-hepatic inferior vena cava (SIVC) preparation for occlusion in that order; PT, PT + SIVC and PT + IIVC + SIVC occlusions were performed during liver resection for six, 42 and 32 patients, respectively. The PT, IIVC and SIVC clamping times were 12.9 ± 2.5, 9.1 ± 2.1 and 5.1 ± 1.4 min, respectively. The mean blood loss was 504.1 ± 234.5 mL. Sixteen patients received blood transfusions. Haemodynamic parameters remained stable. No patients had life-threatening complications or died (Clavien-Dindo grade IV or V). Compared with other techniques used in parallel studies, this technique has the advantage of decreased blood loss in less warm ischaemia time.

CONCLUSION

For complex hepatectomy involving hepatocaval confluence, this newly described stepwise vascular control technique was efficacious and feasible for controlling intraoperative bleeding.

Cost-Effective Surgical Management of Liver Disease Amidst a Financial Crisis

BACKGROUND

Intraoperative use of specialized equipment and disposables contributes to the increasing cost of modern liver surgery. As a response to the recent severe financial crisis in our country we have employed a highly standardized protocol of liver resection that minimizes intraoperative and postoperative costs. Our goal is to evaluate cost-effectiveness of this protocol.

STUDY DESIGN

We evaluated retrospectively all patients who underwent open hepatic resections for 4 years. All resections were performed by the same surgical team under selective hepatic vascular exclusion, i.e., occlusion of the hepatoduodenal ligament and the major hepatic veins, occasionally combined with extrahepatic ligation of the ipsilateral portal vein. Sharp parenchymal transection was performed with a scalpel and hemostasis was achieved with sutures without the use of energy devices. In each case we performed a detailed analysis of costs and surgical outcomes.

RESULTS

Our cohort included 146 patients (median age 63 years). 113 patients were operated for primary or metastatic malignancies and 33 for benign lesions. Operating time was 121 ± 21 min (mean ± SD), estimated blood loss was 310 ± 159 ml (mean ± SD), and hospital stay was 7 ± 5 days (mean ± SD). Six patients required admission in the ICU postoperatively. 90-day mortality was 2.74 %, and 8.9 % of patients developed grade III/IV postoperative complications (Clavien-Dindo classification). Total in-hospital cost excluding physician fees was 6987.63 ± 3838.51 USD (mean ± SD).

CONCLUSIONS

Our analysis suggests that, under pressing economic conditions, the proposed surgical protocol can significantly lessen the financial burden of liver surgery without compromising patient outcomes.

Methods to decrease blood loss during liver resection: a network meta-analysis

BACKGROUND

Liver resection is a major surgery with significant mortality and morbidity. Specialists have tested various methods in attempts to limit blood loss, transfusion requirements, and morbidity during elective liver resection. These methods include different approaches (anterior versus conventional approach), use of autologous blood donation, cardiopulmonary interventions such as hypoventilation, low central venous pressure, different methods of parenchymal transection, different methods of management of the raw surface of the liver, different methods of vascular occlusion, and different pharmacological interventions. A surgeon typically uses only one of the methods from each of these seven categories. The optimal method to decrease blood loss and transfusion requirements in people undergoing liver resection is unknown.

OBJECTIVES

To assess the effects of different interventions for decreasing blood loss and blood transfusion requirements during elective liver resection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and Science Citation Index Expanded to September 2015 to identify randomised clinical trials. We also searched trial registers and handsearched the references lists of identified trials.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) comparing different methods of decreasing blood loss and blood transfusion requirements in people undergoing liver resection.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials and collected data. We assessed the risk of bias using Cochrane domains. We conducted a Bayesian network meta-analysis using the Markov chain Monte Carlo method in WinBUGS 1.4, following the guidelines of the National Institute for Health and Care Excellence Decision Support Unit guidance documents. We calculated the odds ratios (OR) with 95% credible intervals (CrI) for the binary outcomes, mean differences (MD) with 95% CrI for continuous outcomes, and rate ratios with 95% CrI for count outcomes, using a fixed-effect model or random-effects model according to model-fit. We assessed the evidence with GRADE.

MAIN RESULTS

We identified 67 randomised clinical trials involving a total of 6197 participants. All the trials were at high risk of bias. A total of 5771 participants from 64 trials provided data for one or more outcomes included in this review. There was no evidence of differences in most of the comparisons, and where there was, these differences were in single trials, mostly of small sample size. We summarise only the evidence that was available in more than one trial below. Of the primary outcomes, the only one with evidence of a difference from more than one trial under the pair-wise comparison was in the number of adverse events (complications), which was higher with radiofrequency dissecting sealer than with the clamp-crush method (rate ratio 1.85, 95% CrI 1.07 to 3.26; 250 participants; 3 studies; very low-quality evidence). Among the secondary outcomes, the only differences we found from more than one trial under the pair-wise comparison were the following: blood transfusion (proportion) was higher in the low central venous pressure group than in the acute normovolemic haemodilution plus low central venous pressure group (OR 3.19, 95% CrI 1.56 to 6.95; 208 participants; 2 studies; low-quality evidence); blood transfusion quantity (red blood cells) was lower in the fibrin sealant group than in the control (MD -0.53 units, 95% CrI -1.00 to -0.07; 122 participants; 2; very low-quality evidence); blood transfusion quantity (fresh frozen plasma) was higher in the oxidised cellulose group than in the fibrin sealant group (MD 0.53 units, 95% CrI 0.36 to 0.71; 80 participants; 2 studies; very low-quality evidence); blood loss (MD -0.34 L, 95% CrI -0.46 to -0.22; 237 participants; 4 studies; very low-quality evidence), total hospital stay (MD -2.42 days, 95% CrI -3.91 to -0.94; 197 participants; 3 studies; very low-quality evidence), and operating time (MD -15.32 minutes, 95% CrI -29.03 to -1.69; 192 participants; 4 studies; very low-quality evidence) were lower with low central venous pressure than with control. For the other comparisons, the evidence for difference was either based on single small trials or there was no evidence of differences. None of the trials reported health-related quality of life or time needed to return to work.

AUTHORS' CONCLUSIONS

Paucity of data meant that we could not assess transitivity assumptions and inconsistency for most analyses. When direct and indirect comparisons were available, network meta-analysis provided additional effect estimates for comparisons where there were no direct comparisons. However, the paucity of data decreases the confidence in the results of the network meta-analysis. Low-quality evidence suggests that liver resection using a radiofrequency dissecting sealer may be associated with more adverse events than with the clamp-crush method. Low-quality evidence also suggests that the proportion of people requiring a blood transfusion is higher with low central venous pressure than with acute normovolemic haemodilution plus low central venous pressure; very low-quality evidence suggests that blood transfusion quantity (red blood cells) was lower with fibrin sealant than control; blood transfusion quantity (fresh frozen plasma) was higher with oxidised cellulose than with fibrin sealant; and blood loss, total hospital stay, and operating time were lower with low central venous pressure than with control. There is no evidence to suggest that using special equipment for liver resection is of any benefit in decreasing the mortality, morbidity, or blood transfusion requirements (very low-quality evidence). Radiofrequency dissecting sealer should not be used outside the clinical trial setting since there is low-quality evidence for increased harm without any evidence of benefits. In addition, it should be noted that the sample size was small and the credible intervals were wide, and we cannot rule out considerable benefit or harm with a specific method of liver resection.

Reducing inflow occlusion, occlusion duration and blood loss during hepatic resections

BACKGROUND

To assess the changes in blood loss during hepatic resection with improved haemostatic devices such as a bipolar sealing device and a topical haemostatic agent.

METHODS

This retrospective clinical study of prospectively collected data will assess hepatic resections performed by a single surgeon between 2005 and 2013, with the introduction of the two haemostatic techniques in 2009.

RESULTS

A total of 371 hepatic resections (214 from 2005 to 2008 and 157 from 2009 to 2013) were included in this study. Compared with the conventional hepatic resection (2005-2008), the use of haemostatic techniques (2009-2013) significantly reduced the need for inflow occlusion (OR: 0.37, 95% CI: 0.24-0.57, P < 0.001), overall occlusion time (20.8 min versus 25.9 min, P = 0.04) and transfusion requirement (4.6% versus 12%, OR: 0.35, 95% CI: 0.14-0.90, P = 0.02). Mean overall blood loss was reduced post-2009; however, the decrease was not statistically different (401.3 mL versus 470.8 mL, P = 0.27). Subgroup analysis revealed that blood loss was more than halved post-2009 compared with pre-2009 for patients who received pre-operative chemotherapy (324.6 mL versus 738.5 mL, P = 0.005).

CONCLUSION

The use of a bipolar sealing device and a topical haemostatic agent reduces the need for inflow occlusion, overall occlusion time and transfusions in all patients compared with conventional hepatic resections.

Vascular Reconstruction in Hepatic Malignancy

With surgery for hepatic malignancy, there are poor options for chemotherapy; many patients are deemed unresectable because of vascular involvement or location of tumors. Over the past few decades, advances in surgical technique have allowed resection of these tumors with vascular reconstruction to achieve negative margins and improve chances for survival. This article reviews those reconstruction techniques and outcomes in detail, including in situ perfusion and ex vivo liver surgery, and provides a discussion of implications and operative planning for patients with hepatic malignancy in order to provide surgeons with better understanding of these complicated operations.

Retrograde laparoscopic resection of left side of the liver: a safe and effective way

OBJECTIVE

The safety and feasibility of retrograde laparoscopic resection of the left side of the liver.

METHODS

Ninety-three laparoscopic left hepatic lobe cases were selected between August 2010 and August 2014 from our institution. A retrospective cohort study was performed between the antegrade partial hepatectomy group (47 cases; dissection from the first porta hepatis to the second) and the retrograde partial hepatectomy group (46 cases; dissection from the second porta hepatis to the first), to compare the length of time needed for resection, the amount of bleeding, post-operative time in the hospital, and the incidence of major complications, such as bile leakage, abdominal abscess, and post-hepatectomy hemorrhage.

RESULTS

All of the cases had a successful laparoscopic partial hepatectomy without the need for an intraoperative blood transfusion. Patients were able to ambulate on post-operative day 1 and tolerated a liquid diet on post-operative day 1 or 2. There were no statistical differences of post-operative hospital length of stay or incidence of major complications between the two groups. Both duration of resection and the amount of bleeding were less in the retrograde group than of those in the antegrade group, due to the lower incidence of hepatic vein injury in the retrograde group.

CONCLUSION

Occlusion of both the inflow and outflow hepatic vessels combined with retrograde hepatectomy from the second porta hepatis to the first, demonstrated less hemorrhage and lower incidence of hepatic veins injury during laparoscopic partial hepatectomy.

Comparative Effects of Ischemic Preconditioning and Iron Chelation in Hepatectomy

PURPOSE/AIM

Major hepatectomies can result in severe ischemia/reperfusion (I/R) injury of the liver. The aim of this survey is to comparatively evaluate the effects of a surgical and a pharmacological hepatoprotective modality on the liver remnant in a porcine model of hepatectomy.

MATERIAL AND METHODS

Twenty-one Landrace pigs were randomly divided into three groups: a control group (CON) (n = 7), an Ischemic Preconditioning (PRE) group (n = 7) and a Desferoxamine (DFX) treated one (n = 7). Animals were subjected to 120 min of liver ischemia with subsequent 75% hepatectomy followed by 24-hr reperfusion. In all animals, continuous intracranial pressure (ICP) monitoring was employed. Blood samples were collected at t0, t6, t12, and t24 hrs after reperfusion. Liver remnant specimens were excised for histological examination.

RESULTS

In the PRE group, ICP was statistically lower at t6 time point compared to CON group and in comparison with t0. In addition, ICP was significantly lower at all-time points after reperfusion in the DFX group. Finally, with regard to DFX and PRE group correlation, ICP was significantly lower at t0, t12, and t24 time points after reperfusion in the DFX group. In the PRE group, NH3 levels were significantly lower at t12 after reperfusion compared to CON and DFX groups. Histological evaluation elucidated significantly less hepatocellular necrosis, apoptosis, and degeneration in the PRE and DFX groups correlated to CON group.

CONCLUSIONS

Both hepatoprotective modalities including PRE and DFX administration are associated with lower ICP levels and correlated with attenuated liver remnant injury.

Macrosteatotic and nonmacrosteatotic grafts respond differently to intermittent hepatic inflow occlusion: Comparison of recipient survival

Intermittent hepatic inflow occlusion (IHIO) during liver graft procurement is known to confer protection against graft ischemia/reperfusion injury and thus may benefit the recipient's outcome. We evaluated whether the protective effect of IHIO differs with the presence of macrosteatosis (MaS) and with an increase or decrease in the cumulative occlusion time. The subgroup of 188 recipients who received grafts with MaS was divided into 3 groups according to the number of total IHIO rounds during graft procurement: no IHIO, n = 70; 1 to 2 rounds of IHIO, n = 50; and ≥3 rounds of IHIO, n = 68. Likewise, the subgroup of 200 recipients who received grafts without MaS was divided into 3 groups: no IHIO, n = 108; 1 to 2 rounds of IHIO, n = 40; and ≥3 rounds of IHIO, n = 52. The Cox model was applied to evaluate the association between the number of total IHIO rounds and recipient survival separately in the subgroup of MaS recipients and the subgroup of non-MaS recipients. Analyzed covariables included the etiology, Milan criteria, transfusion, immunosuppression, and others. In the subgroup of MaS recipients, 1 to 2 rounds of IHIO were favorably associated with recipient survival [hazard ratio (HR), 0.29; 95% confidence interval (CI), 0.10-0.80; P = 0.03 after Bonferroni correction], whereas ≥3 rounds of IHIO were not associated with recipient survival (HR, 0.56; 95% CI, 0.25-1.23). In the subgroup of non-MaS recipients, neither 1 to 2 rounds of IHIO (HR, 0.69; 95% CI, 0.30-1.61) nor ≥3 rounds of IHIO (HR, 0.91; 95% CI, 0.42-1.96) were associated with recipient survival. In conclusion, 1 to 2 rounds of IHIO may be used for the procurement of MaS grafts with potential benefit for recipient survival, whereas IHIO has a limited impact on recipient survival regardless of the cumulative occlusion time when it is used for non-MaS grafts.

Epidural analgesia and perioperative kidney function after major liver resection

BACKGROUND

Epidural analgesia (EDA) is a common analgesia regimen in liver resection, and is accompanied by sympathicolysis, peripheral vasodilatation and hypotension in the context of deliberate intraoperative low central venous pressure. This associated fall in mean arterial pressure may compromise renal blood pressure autoregulation and lead to acute kidney injury (AKI). This study investigated whether EDA is a risk factor for postoperative AKI after liver surgery.

METHODS

The incidence of AKI was investigated retrospectively in patients who underwent liver resection with or without EDA between 2002 and 2012. Univariable and multivariable analyses were performed including recognized preoperative and intraoperative predictors of posthepatectomy renal failure.

RESULTS

A series of 1153 patients was investigated. AKI occurred in 8·2 per cent of patients and was associated with increased morbidity (71 versus 47·3 per cent; P = 0·003) and mortality (21 versus 0·3 per cent; P <  0·001) rates. The incidence of AKI was significantly higher in the EDA group (10·1 versus 3·7 per cent; P = 0·003). Although there was no significant difference in the incidence of AKI between patients undergoing minor hepatectomy with or without EDA (5·2 versus 2·7 per cent; P = 0·421), a substantial difference in AKI rates occurred in patients undergoing major hepatectomy (13·8 versus 5·0 per cent; P = 0·025). In multivariable analysis, EDA remained an independent risk factor for AKI after hepatectomy (P = 0·040).

CONCLUSION

EDA may be a risk factor for postoperative AKI after major hepatectomy.

Bleeding control during laparoscopic liver resection: a review of literature

Despite the established advantages of laparoscopy, bleeding control during laparoscopic liver resection (LLR) is a liver-specific improvement. The 2nd International Consensus Conference on Laparoscopic Liver Resection was held in October 2014 at Morioka, Japan. One of the most capital questions was: What is essential in bleeding control during LLR? In order to correctly address this question, we conducted a comprehensive review of the literature. Essential points based on personal experience of the expert panel are also discussed. A total of 54 publications were identified. Based on this analysis, the working group built these recommendations: (1) a pneumoperitoneum of 10-14 mmHg should be used as it allows a good control of the bleeding without significant modifications of hemodynamics; (2) a low central venous pressure (<5 mmHg) should be used; (3) laparoscopy facilitates inflow and outflow control; and (4) surgeons should be experienced with the use of all surgical devices for liver transection and should master laparoscopic suture before starting LLR. Precoagulation with radiofrequency can be useful, particularly in cases of atypical resection. These recommendations are mostly based on experts' opinions and on B or C quality of evidence grade studies. More prospective data are required to confirm these results.

Systematic review of pathophysiological changes following hepatic resection

OBJECTIVES

Major hepatic resection is now performed frequently and with relative safety, but is accompanied by significant pathophysiological changes. The aim of this review is to describe these changes along with interventions that may help reduce the risk for adverse outcomes after major hepatic resection.

METHODS

The MEDLINE, EMBASE and CENTRAL databases were searched for relevant literature published from January 2000 to December 2011. Broad subject headings were 'hepatectomy/', 'liver function/', 'liver failure/' and 'physiology/'.

RESULTS

Predictable changes in blood biochemistry and coagulation occur following major hepatic resection and alterations from the expected path indicate a complicated course. Susceptibility to sepsis, functional renal impairment, and altered energy metabolism are important sequelae of post-resection liver failure.

CONCLUSIONS

The pathophysiology of post-resection liver failure is difficult to reverse and thus strategies aimed at prevention are key to reducing morbidity and mortality after liver surgery.

Surrogate endpoints in liver surgery related trials: a systematic review of the literature

BACKGROUND

Although the safety of liver surgery has improved enormously, hepatic surgery continues to face challenging complications. Therefore, improvements supported by evidence-based guidelines are still required. The conduct of randomized controlled trials in liver surgery using dichotomous outcomes requires a large sample size. The use of surrogate endpoints (SEPs) reduces sample size but SEPs should be validated before use.

AIM

The aim of this review was to summarize the SEPs used in hepatic surgery related trials, their definitions and recapitulating the evidence validating their use.

METHOD

A systematic computerized literature search in the biomedical database PubMed using the MeSH terms 'hepatectomy' or 'liver resection' or 'liver transection' was conducted. Search was limited to papers written in the English language and published between 1 January 2000 and 1 January 2010.

RESULTS

A total of 593 articles met the search terms and 49 articles were included in the final selection. Standard biochemical liver functions tests were the most frequently used SEP (32 of 49 the studies). The used definitions of SEPs varied greatly among the studies. Most studies referred to earlier published material to justify their choice of SEP. However, no validating studies were found.

CONCLUSION

Many SEPs are used in liver surgery trials however there is little evidence validating them.

Laparoscopic liver resection with selective prior vascular control

BACKGROUND

Selective control of vascular inflow can reduce blood loss and transfusion rates and may be particularly efficient in laparoscopic liver resection (LLR). The aim of this study was to evaluate the efficacy of selective prior vascular control (PVC) in patients undergoing laparoscopic or open liver resections (OLR).

METHODS

Between 1999 and 2008, 52 patients underwent LLR with PVC with prospective data collection and were compared with patients undergoing OLR with PVC.

RESULTS

There was no difference in the operative time between the 2 groups. Blood loss and transfusion rates were lower in patients who underwent LLR (367 vs 589 mL, P = .001; 3.8% vs 17.3%, P = .05, respectively). Morbidity did not differ significantly between the 2 groups. Hospital stay was longer in the OLR group (11.0 vs 7.4 days, P = .001).

CONCLUSIONS

PVC during LLR was feasible and improved intraoperative and postoperative results. Selective PVC should be obtained in LLR whenever possible.

Laser speckle contrast imaging for assessment of liver microcirculation

OBJECTIVE

Laser speckle contrast imaging (LSCI) is a novel technique for microcirculation imaging not previously used in the liver. The aim of the present experimental study was to evaluate the use of LSCI for assessing liver microcirculation.

MATERIALS AND METHODS

In six male Wistar rats, the median liver lobe was exposed through a midline laparotomy. Liver blood perfusion was measured simultaneously with LSCI and sidestream dark-field (SDF) imaging at baseline and during sequential temporary occlusions of the portal vein, hepatic artery, and total blood inflow occlusion. Both the inter-individual variability associated with perfusion sampling area and comparisons in perfusion measurements between both imaging techniques were investigated and validated for the application of LSCI in the liver.

RESULTS

Occlusion of the hepatic artery, portal vein, and total inflow occlusion resulted in a significant decrease in LSCI signal to 74.7±6.4%, 15.0±2.3%, and 10.4±0.5% respectively (p<0.005 vs. baseline). The LSCI perfusion units correlated with sinusoidal blood flow velocity as measured with SDF imaging (Pearson's r=0.94, p<0.001). In a 10 mm diameter region of interest, as measured with LSCI, baseline inter-individual variability measured by the coefficient of variability was 13%.

CONCLUSION

Alterations in LSCI signal during sequential inflow occlusions were in accordance with previously published results on hepatic hemodynamics in the rat and correlated well with our SDF imaging-derived sinusoidal blood flow velocity measurements. We found that LSCI was able to produce reproducible real-time blood perfusion measurements of hepatic microcirculation. Compared to established techniques for liver blood perfusion measurements LSCI holds the advantages of non-contact measurements over large surfaces with a high speed of data acquisition.

Portal triad clamping versus other methods of vascular control in liver resection: a systematic review and meta-analysis

BACKGROUND

Portal triad clamping (PTC) is the most commonly used method of achieving vascular control during liver resection. However, the efficacy and safety of PTC, compared with those of other methods of vascular control, are uncertain.

METHODS

A systematic review was conducted to identify randomized controlled trials (RCTs) comparing PTC with other methods of vascular control during liver resection. Endpoints included in-hospital mortality, need for transfusion, number of complications and length of hospital stay. Meta-analyses were performed using a random-effects model.

RESULTS

Ten RCTs were identified; these included a total of 820 patients. No statistically significant differences between PTC and other forms of vascular control in liver resection were demonstrated.

CONCLUSIONS

There is no evidence, on the basis of this meta-analysis of RCTs, of any difference between PTC and other forms of vascular control in liver resection.

Alternative management of anatomical right hemihepatectomy using ligation of inflow and outflow vessels without hilus dissection

BACKGROUND AND AIM

The conventional method of anatomical right hemihepatectomy (ARHH) requires hilus dissection. We report a method without hilus dissection to minimize intraoperative bleeding.

METHODS

We retrospectively evaluated data of 107 patients who received ARHH involving ligation of corresponding inflow and outflow vessels (LCIOV) without hilus dissection between January 2000 and October 2008. Results were compared to those of patients who underwent non-anatomical right hemihepatectomies (NARHH).

RESULTS

The two groups had similar gender and age (both, P>0.05). The LCIOV group had a higher percentage of patients without intrahepatic metastases (94.6% vs 80.3%, P=0.003). Hepatocellular carcinoma (HCC) lesion size (9.3 vs 10.2, P=0.023), durations of inferior vena cava occlusion (4 vs 4.7, P<0.001) and portal triad occlusion (7 vs 11, P<0.001), blood loss (430 vs 580 mL, P=0.001), transfusion volume (300 vs 520 mL, P<0.001), and measures of postoperative liver function (e.g. maximum aspartate aminotransferase [AST]) of the LCIOV group were also significantly less than the NARHH group. Larger hepatic cavernous hemangiomas (HCH) lesion size (16.2 vs 13.0, P<0.001), longer operative time (168 vs 154 min, P=0.017), and a lower percentage of patients with inferior vena cava occlusion (17.8% vs 35.2%, P=0.001), pleural effusions (19.3% vs 30.9%, P=0.042), and blood transfusions (10.3% vs 75.0%, P<0.001) were found in the LCIOV group.

CONCLUSION

The reported method is a safe and bloodless technique for right hemihepatectomy in select patients.

The role of serum interleukin-8 in hepatic resections

PURPOSE

Interleukin-8 (IL-8) is a neutrophil chemotactic factor, which is associated with some inflammatory diseases and various types of surgical stress. The aim of this study was to investigate whether the early postoperative serum IL-8 level may potentially be a new indicator of a surgical stress in patients undergoing a hepatic resection.

METHODS

The serum IL-8 levels were measured in 37 patients who underwent a hepatectomy. The serum IL-8 levels were serially measured using an enzyme-linked immunosorbent assay both before and after a hepatic resection. In addition, the correlation between the postoperative IL-8 value and several clinical variables were examined.

RESULTS

The mean level of IL-8 significantly increased immediately after the operation (P < 0.01 vs before the operation) and decreased on the first postoperative day (POD 1, P < 0.05 vs after the operation). The early postoperative IL-8 levels positively correlated with the length of the procedure (r = 0.383; P < 0.05), the estimated blood loss (r = 0.483; P < 0.01) and the serum bilirubin level on POD 1 (r = 0.390; P < 0.05), and inversely correlated with the white blood cell counts (r = -0.388; P < 0.05) and lymphocyte counts on POD 1 (r = -0.424; P < 0.05). In a comparison of the postoperative IL-8 levels with the surgical factors, there was a significant difference in the extension of the resection (P < 0.05) and in blood transfusion. The patients with a fever of more than 38 degrees C showed higher levels of IL-8 immediately after the operation than those without fever (P < 0.01).

CONCLUSIONS

The early postoperative serum IL-8 level was found to correlate with the degree of the severity of surgery in patients undergoing a hepatic resection, and it is also considered to be a new indicator of surgical stress and liver injury.

Ischemic preconditioning confers antiapoptotic protection during major hepatectomies performed under combined inflow and outflow exclusion of the liver. A randomized clinical trial

BACKGROUND

Extensive experimental studies and a few clinical series have shown that ischemic preconditioning (IPC) attenuates oxidative ischemia/reperfusion (I/R) injuries in liver resections performed under inflow vascular control. Selective hepatic vascular exclusion (SHVE) employed during hepatectomies completely deprives the liver of blood flow, as it entails simultaneous clamping of the portal triad and the main hepatic veins. The aim of the present study was to identify whether IPC can also protect hepatocytes during liver resections performed under SHVE.

METHODS

Patients undergoing major liver resection were randomly assigned to have either only SHVE (control group, n = 43) or SHVE combined with IPC--10 min of ischemia followed by 15 min of reperfusion before SHVE was applied (IPC group, n = 41).

RESULTS

The two groups were comparable with regard to age, liver resection volume, blood loss and transfusions, warm ischemic time, and total operative time. In liver remnant biopsies obtained 60 min post-reperfusion, IPC patients had significantly fewer cells stained positive by TUNEL compared to controls (19% +/- 8% versus 45% +/- 12%; p < 0.05). Also IPC patients had attenuated hepatocyte necrosis, systemic inflammatory response, and oxidative stress as manifested by lower postoperative peak values of aspartate transaminase, interleukin-6, interleukin-8, and malondialdehyde compared to controls. Morbidity was similar for the two groups, as were duration of intensive care unit stay and extent of total hospital stay.

CONCLUSIONS

In major hepatectomies performed under SHVE, ischemic preconditioning appears to attenuate apoptotic response of the liver remnant, possibly through alteration of inflammatory and oxidative pathways.

Portal triad clamping versus vascular exclusion for vascular control during hepatic resection: a systematic review and meta-analysis

OBJECTIVE

To compare the clinical outcome of patients undergoing liver resection under portal triad clamping (PTC) versus hepatic vascular exclusion (HVE).

METHODS

A systematic literature search was performed following the guidelines of the Cochrane collaboration. Randomized controlled trials (RCT) comparing PTC to any technique of HVE were eligible for inclusion. Two authors independently assessed methodological quality of included trials and extracted data on overall morbidity, mortality, cardiopulmonary and hepatic morbidity, intraoperative blood loss, transfusion rates, postoperative transaminase and bilirubin levels, prothrombin time, and hospital stay. Meta-analyses were performed using a random-effects model.

RESULTS

Of the 1,383 identified references, four RCTs were finally included. These trials compared PTC to selective hepatic vascular exclusion (SHVE), total hepatic vascular exclusion (THVE), and a modified technique of HVE (MTHVE), respectively. Meta-analyses revealed no significant difference in morbidity and mortality between PTC and techniques of HVE. Further analyses showed significantly reduced overall morbidity for the PTC compared to the THVE group. There was a significantly lower transfusion rate for HVE compared to PTC.

CONCLUSION

Hepatic vascular exclusion does not offer any benefit regarding outcome of patients undergoing hepatic resection compared to PTC alone. Further, well-designed RCTs evaluating adequate vascular control in major hepatectomy and in patients with underlying liver disease appear justified.

Methods of vascular occlusion for elective liver resections

BACKGROUND

Vascular occlusion is used to reduce blood loss during liver resection surgery. Various methods of vascular occlusion have been suggested.

OBJECTIVES

To compare the benefits and harms of different methods of vascular occlusion during elective liver resection.

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 2008.

SELECTION CRITERIA

We included randomised clinical trials comparing different methods of vascular occlusion during elective liver resections (irrespective of language or publication status).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for inclusion and independently extracted the data. We calculated the risk ratio or mean difference with 95% confidence intervals using fixed-effect and random-effects models based on intention-to-treat or available data analysis.

MAIN RESULTS

Ten trials including 657 patients compared different methods of vascular occlusion. All trials were of high risk of bias. Only one or two trials were included under each comparison. There was no statistically significant differences in mortality, liver failure, or other morbidity between any of the comparisons.Hepatic vascular occlusion does not decrease the blood transfusion requirements. It decreases the cardiac output and increases the systemic vascular resistance. In the comparison between continuous portal triad clamping and intermittent portal triad clamping, four of the five liver failures occurred in patients with chronic liver diseases undergoing the liver resections using continuous portal triad clamping. In the comparison between selective inflow occlusion and portal triad clamping, all four patients with liver failure occurred in the selective inflow occlusion group. There was no difference in any of the other important outcomes in any of the comparisons.

AUTHORS' CONCLUSIONS

In elective liver resection, hepatic vascular occlusion cannot be recommended over portal triad clamping. Intermittent portal triad clamping seems to be better than continuous portal triad clamping at least in patients with chronic liver disease. There is no evidence to support selective inflow occlusion over portal triad clamping. The optimal method of intermittent portal triad clamping is not clear. There is no evidence for any difference between the ischaemic preconditioning followed by vascular occlusion and intermittent vascular occlusion for liver resection in patients with non-cirrhotic livers. Further randomised trials of low risk of bias are needed to determine the optimal technique of vascular occlusion.

WITHDRAWN: Methods of vascular occlusion for elective liver resections

BACKGROUND

Vascular occlusion is used to reduce blood loss during liver resection surgery. There is considerable controversy regarding whether vascular occlusion should be used or not during elective liver resections. The method of vascular occlusion employed is also controversial. There is also considerable debate on the role of ischaemic preconditioning before vascular occlusion.

OBJECTIVES

To assess the advantages (decreased blood loss and peri-operative morbidity) and disadvantages (liver dysfunction from ischaemia) of vascular occlusion during liver resections. To compare the advantages (in decreasing blood loss or decreasing ischaemia-reperfusion injury) and disadvantages of different types of vascular occlusion versus total, continuous portal triad clamping.

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 2007.

SELECTION CRITERIA

We included randomised clinical trials comparing vascular occlusion versus no vascular occlusion during elective liver resections (irrespective of language or publication status). We also included randomised clinical trials comparing the different methods of vascular occlusion and those investigating the role of ischaemic preconditioning in liver resection.

DATA COLLECTION AND ANALYSIS

We collected the data on the characteristics of the trial, methodological quality of the trials, mortality, morbidity, blood loss, blood transfusion requirements, liver function tests, markers of neutrophil activation, operating time, and hospital stay. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each binary outcome we calculated the odds ratio (OR) with 95% confidence intervals (CI) based on intention-to-treat analysis. For continuous outcomes, we calculated the weighted mean difference (WMD) with 95% confidence intervals.

MAIN RESULTS

We identified a total of 16 randomised trials. Five trials including 331 patients compared vascular occlusion (n = 166) versus no vascular occlusion (n = 165). Six trials including 521 patients compared different methods of vascular occlusion. Three trials including 210 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 105) versus no ischaemic preconditioning (n = 105). Two trials including 127 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 63) versus intermittent portal triad clamping (n = 64).The blood loss was significantly lower in vascular occlusion compared with no vascular occlusion. The liver enzymes were significantly elevated in the vascular occlusion group compared with no vascular occlusion. There was no difference in the mortality, liver failure, or other morbidities. Four of the five trials comparing vascular occlusion and no vascular occlusion used intermittent vascular occlusion. Trials comparing complete inflow and outflow occlusion to the liver, ie, hepatic vascular exclusion and portal triad clamping demonstrate significant detrimental haemodynamic changes in hepatic vascular exclusion compared to portal triad clamping. There was no significant difference in the number of units transfused and the number of patients needing transfusion. There was no difference in mortality, liver failure, or morbidity between total and selective methods of portal triad clamping. All four cases of mortality and liver failure in the comparison between the intermittent and continuous portal triad clamping occurred in the continuous portal triad clamping (statistically not significant). Intermittent portal triad clamping does not increase the total blood loss or operating time compared to continuous portal triad clamping.There was no statistically significant difference in the mortality, liver failure, morbidity, blood loss, or haemodynamic changes between ischaemic preconditioning versus no ischaemic preconditioning before continuous portal triad clamping. Liver enzymes used as markers of liver injury were significantly lower in the early post-operative period in the ischaemic preconditioning group. The intensive therapy unit stay and hospital stay were statistically significantly lower in the ischaemic preconditioning group than in the no ischaemic preconditioning group.There was no statistically significant difference in the mortality, liver failure, morbidity, intensive therapy unit stay, or hospital stay between ischaemic preconditioning before continuous portal triad clamping and intermittent portal triad clamping. The blood loss and transfusion requirements were lower in the ischaemic preconditioning group. Aspartate aminotransferase level was lower in the intermittent portal triad clamping group than the ischaemic preconditioning group on the third post-operative day. There was no difference in the peak aspartate aminotransferase levels or in the aspartate aminotransferase levels on first or sixth post-operative days of aspartate aminotransferase .

AUTHORS' CONCLUSIONS

Intermittent vascular occlusion seems safe in liver resection. However, it does not seem to decrease morbidity. Among the different methods of vascular occlusion, intermittent portal triad clamping has most evidence to support the clinical application. Hepatic vascular exclusion cannot be recommended routinely. Ischaemic preconditioning before continuous portal triad clamping may be of clinical benefit in reducing intensive therapy unit and hospital stay.

Decreased hepatosplanchnic antioxidant uptake during hepatic ischaemia/reperfusion in patients undergoing liver resection

Oxidative stress mediates cell injury during ischaemia/reperfusion. On the other hand, experimental findings suggest that ROS (reactive oxygen species) induce processes leading to ischaemic preconditioning. The extent and source of oxidative stress and its effect on antioxidant status in the human liver during intermittent ischaemia and reperfusion remains ill-defined. Therefore the aim of the present study was to investigate the occurrence of oxidative stress in humans undergoing liver resection. Liver biopsies, and arterial and hepatic venous blood samples were taken from ten patients undergoing hepatectomy with an intermittent Pringle manoeuvre. Plasma MDA (malondialdehyde) and hepatic GSSG levels were measured as markers of oxidative stress and plasma uric acid as a marker of xanthine oxidase activity. In addition, changes in hepatosplanchnic consumption of plasma antioxidants and hepatic levels of carotenoids and glutathione (GSH) were measured. After ischaemia, hepatosplanchnic release of MDA and increased hepatic GSSG levels were found. This was accompanied by the release of uric acid, reflecting xanthine oxidase activity. During reperfusion, ongoing oxidative stress was observed by further increases in hepatic GSSG content and hepatosplanchnic MDA release. Uric acid release was minimal during reperfusion. A gradual decrease in plasma antioxidant capacity and net hepatosplanchnic antioxidant uptake was observed upon prolonged cumulative ischaemia. Oxidative stress occurs during hepatic ischaemia in man mainly due to xanthine oxidase activity. Interestingly, the gradual decline in plasma antioxidant capacity and net hepatosplanchnic antioxidant uptake during prolonged cumulative ischaemia, preserved both hydrophilic and lipophilic hepatic antioxidant levels. Decreasing plasma levels and net hepatosplanchnic uptake of plasma antioxidants may warrant antioxidant supplementation, although it should be clarified to what extent limitation of oxidative stress compromises ROS-dependent pathways of ischaemic preconditioning.

JunD protects the liver from ischemia/reperfusion injury by dampening AP-1 transcriptional activation

The AP-1 transcription factor modulates a wide range of cellular processes, including cellular proliferation, programmed cell death, and survival. JunD is a major component of the AP-1 complex following liver ischemia/reperfusion (I/R) injury; however, its precise function in this setting remains unclear. We investigated the functional significance of JunD in regulating AP-1 transcription following partial lobar I/R injury to the liver, as well as the downstream consequences for hepatocellular remodeling. Our findings demonstrate that JunD plays a protective role, reducing I/R injury to the liver by suppressing acute transcriptional activation of AP-1. In the absence of JunD, c-Jun phosphorylation and AP-1 activation in response to I/R injury were elevated, and this correlated with increased caspase activation, injury, and alterations in hepatocyte proliferation. The expression of dominant negative JNK1 inhibited c-Jun phosphorylation, AP-1 activation, and hepatic injury following I/R in JunD-/- mice but, paradoxically, led to an enhancement of AP-1 activation and liver injury in JunD+/- littermates. Enhanced JunD/JNK1-dependent liver injury correlated with the acute induction of diphenylene iodonium-sensitive NADPH-dependent superoxide production by the liver following I/R. In this context, dominant negative JNK1 expression elevated both Nox2 and Nox4 mRNA levels in the liver in a JunD-dependent manner. These findings suggest that JunD counterbalances JNK1 activation and the downstream redox-dependent hepatic injury that results from I/R, and may do so by regulating NADPH oxidases.

A simple technique ligating the corresponding inflow and outflow vessels during anatomical left hepatectomy

BACKGROUND

Massive bleeding remains one of main factors of morbidity and death in liver resections. For this reason, the Pringle maneuver or total vascular exclusion is commonly used during liver resection. However, ischemic damage is still a major problem. Some surgeons used the "glissonean" approach for bleeding control, but the technique is tedious and also time consuming, with high incidence of bile leaks in the postoperative period. The aim of this paper is to describe a new bleeding control technique, rapid ligation of the corresponding inflow and outflow vessels without hilus dissection before the parenchyma transection during anatomical left liver resection and to analyze the feasibility, blood loss, transfusion requirements, and postoperative complications.

MATERIALS AND METHODS

During the past 18 years, we used the new hemorrhage control technique in left liver resection in 630 patients with malignant or benign tumors.

RESULTS

The median blood loss in all 630 patients was 110 +/- 250 ml (range 50-750), and no patient required blood transfusion. The median total operative time was 77 +/- 35 min (range 25-155). No bile leaks and liver failure of the patients occurred postoperatively. There was no death within 30 postoperative days.

CONCLUSION

The rapid ligation of the corresponding inflow and outflow vessels without hilus dissection before the parenchyma transection is a feasible, safe, and bloodless technique during the left liver resection.

Methods of vascular occlusion for elective liver resections

BACKGROUND

Vascular occlusion is used to reduce blood loss during liver resection surgery. There is considerable controversy regarding whether vascular occlusion should be used or not during elective liver resections. The method of vascular occlusion employed is also controversial. There is also considerable debate on the role of ischaemic preconditioning before vascular occlusion.

OBJECTIVES

To assess the advantages (decreased blood loss and peri-operative morbidity) and disadvantages (liver dysfunction from ischaemia) of vascular occlusion during liver resections. To compare the advantages (in decreasing blood loss or decreasing ischaemia-reperfusion injury) and disadvantages of different types of vascular occlusion versus total, continuous portal triad clamping.

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 2007.

SELECTION CRITERIA

We included randomised clinical trials comparing vascular occlusion versus no vascular occlusion during elective liver resections (irrespective of language or publication status). We also included randomised clinical trials comparing the different methods of vascular occlusion and those investigating the role of ischaemic preconditioning in liver resection.

DATA COLLECTION AND ANALYSIS

We collected the data on the characteristics of the trial, methodological quality of the trials, mortality, morbidity, blood loss, blood transfusion requirements, liver function tests, markers of neutrophil activation, operating time, and hospital stay. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each binary outcome we calculated the odds ratio (OR) with 95% confidence intervals (CI) based on intention-to-treat analysis. For continuous outcomes, we calculated the weighted mean difference (WMD) with 95% confidence intervals.

MAIN RESULTS

We identified a total of 16 randomised trials. Five trials including 331 patients compared vascular occlusion (n = 166) versus no vascular occlusion (n = 165). Six trials including 521 patients compared different methods of vascular occlusion. Three trials including 210 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 105) versus no ischaemic preconditioning (n = 105). Two trials including 127 patients compared ischaemic preconditioning before continuous portal triad clamping (n = 63) versus intermittent portal triad clamping (n = 64). The blood loss was significantly lower in vascular occlusion compared with no vascular occlusion. The liver enzymes were significantly elevated in the vascular occlusion group compared with no vascular occlusion. There was no difference in the mortality, liver failure, or other morbidities. Four of the five trials comparing vascular occlusion and no vascular occlusion used intermittent vascular occlusion. Trials comparing complete inflow and outflow occlusion to the liver, ie, hepatic vascular exclusion and portal triad clamping demonstrate significant detrimental haemodynamic changes in hepatic vascular exclusion compared to portal triad clamping. There was no significant difference in the number of units transfused and the number of patients needing transfusion. There was no difference in mortality, liver failure, or morbidity between total and selective methods of portal triad clamping. All four cases of mortality and liver failure in the comparison between the intermittent and continuous portal triad clamping occurred in the continuous portal triad clamping (statistically not significant). Intermittent portal triad clamping does not increase the total blood loss or operating time compared to continuous portal triad clamping. There was no statistically significant difference in the mortality, liver failure, morbidity, blood loss, or haemodynamic changes between ischaemic preconditioning versus no ischaemic preconditioning before continuous portal triad clamping. Liver enzymes used as markers of liver injury were significantly lower in the early post-operative period in the ischaemic preconditioning group. The intensive therapy unit stay and hospital stay were statistically significantly lower in the ischaemic preconditioning group than in the no ischaemic preconditioning group. There was no statistically significant difference in the mortality, liver failure, morbidity, intensive therapy unit stay, or hospital stay between ischaemic preconditioning before continuous portal triad clamping and intermittent portal triad clamping. The blood loss and transfusion requirements were lower in the ischaemic preconditioning group. Aspartate aminotransferase level was lower in the intermittent portal triad clamping group than the ischaemic preconditioning group on the third post-operative day. There was no difference in the peak aspartate aminotransferase levels or in the aspartate aminotransferase levels on first or sixth post-operative days of aspartate aminotransferase.

AUTHORS' CONCLUSIONS

Intermittent vascular occlusion seems safe in liver resection. However, it does not seem to decrease morbidity. Among the different methods of vascular occlusion, intermittent portal triad clamping has most evidence to support the clinical application. Hepatic vascular exclusion cannot be recommended routinely. Ischaemic preconditioning before continuous portal triad clamping may be of clinical benefit in reducing intensive therapy unit and hospital stay.

Ischemic preconditioning for major liver resection under vascular exclusion of the liver preserving the caval flow: a randomized prospective study

BACKGROUND

Two randomized prospective studies suggested that ischemic preconditioning (IP) protects the human liver against ischemia-reperfusion injury after hepatectomy performed under continuous clamping of the portal triad. The primary goal of this study was to determine whether IP protects the human liver against ischemia-reperfusion injury after hepatectomy under continuous vascular exclusion with preservation of the caval flow.

STUDY DESIGN

Sixty patients were randomly divided into two groups: with (n=30; preconditioning group) and without (n=30; control group) IP (10 minutes of portal triad clamping and 10 minutes of reperfusion) before major hepatectomy under vascular exclusion of the liver preserving the caval flow. Serum concentrations of aspartate transferase, alanine transferase, glutathione-S-transferase, and bilirubin and prothrombin time were regularly determined until discharge and at 1 month. Morbidity and mortality were determined in both groups.

RESULTS

Peak postoperative concentrations of aspartate transferase were similar in the groups with and without IP (851 +/- 1,733 IU/L and 427 +/- 166 IU/L respectively, p=0.2). A similar trend toward a higher peak concentration of alanine transferase and glutathione-S-transferase was indeed observed in the preconditioning group compared with the control group. Morbidity and mortality rates and lengths of ICU and hospitalization stays were similar in both groups.

CONCLUSIONS

IP does not improve liver tolerance to ischemia-reperfusion after hepatectomy under vascular exclusion of the liver with preservation of the caval flow. This maneuver does not improve postoperative liver function and does not affect morbidity or mortality rates. The clinical use of IP through 10 minutes of warm ischemia in this technique of hepatectomy is not currently recommended.

Vascular control during hepatectomy: review of methods and results

The various techniques of hepatic vascular control are presented, focusing on the indications and drawbacks of each. Retrospective and prospective clinical studies highlight aspects of the pathophysiology, indications, and morbidity of the various techniques of hepatic vascular control. Newer perspectives on the field emerge from the introduction of ischemic preconditioning and laparoscopic hepatectomy. A literature review based on computer searches in Index Medicus and PubMed focuses mainly on prospective studies comparing techniques and large retrospective ones. All methods of hepatic vascular control can be applied with minimal mortality by experienced surgeons and are effective for controlling bleeding. The Pringle maneuver is the oldest and simplest of these methods and is still favored by many surgeons. Intermittent application of the Pringle maneuver and hemihepatic occlusion or inflow occlusion with extraparenchymal control of major hepatic veins is particularly indicated for patients with abnormal parenchyma. Total hepatic vascular exclusion is associated with considerable morbidity and hemodynamic intolerance in 10% to 20% of patients. It is absolutely indicated only when extensive reconstruction of the inferior vena cava (IVC) is warranted. Major hepatic veins/ and limited IVC reconstruction has been also achieved under inflow occlusion with extraparenchymal control of major hepatic veins or even using the intermittent Pringle maneuver. Ischemic preconditioning is strongly recommended for patients younger than 60 years and those with steatotic livers. Each hepatic vascular control technique has its place in liver surgery, depending on tumor location, underlying liver disease, patient cardiovascular status, and, most important, the experience of the surgical and anesthesia team.