Liver resection with normothermic ischaemia exceeding 1 h

Complex Hepatectomy Under Total Vascular Exclusion of the Liver Preserving the Caval Flow with Portal Hypothermic Perfusion and Temporary Portacaval Shunt: A Proof of Concept

BACKGROUND

Hypothermic liver perfusion decreases ischemia/reperfusion injury during hepatectomy under standard total vascular exclusion (TVE) of the liver. This surgery needs venovenous bypass and is hampered by high morbi-mortality. TVE preserving the inferior vena cava (IVC) flow is hemodynamically well tolerated but remains limited in duration when performed under liver normothermia. The objective of this study was to report the results of TVE preserving the caval flow, modified to allow hypothermic liver perfusion and obviate splanchnic congestion.

PATIENTS AND METHODS

The technique, indicated for tumors abutting large tributaries of the hepatic veins but sparing their roots in IVC and the latter, was applied when TVE was anticipated to last for ≥ 60 min. It combines continuous TVE preserving the IVC flow with hypothermic liver perfusion and temporary portacaval shunt (PCS). Results are given as median (range).

RESULTS

Vascular control was achieved in 13 patients with excellent hemodynamical tolerance. PCS was direct or via an interposed synthetic graft (five and eight cases, respectively). Liver temperature dropped to 16.5 (6-24) °C under perfusion of 2 (2-4) L of cold perfusate. TVE lasted 67 (54-125) min and 4.5 (0-8) blood units were transfused. Resection was major in nine cases and was complete in all cases. Five complications occurred in four patients, and the 90-day mortality rate was zero.

CONCLUSIONS

This technique maintains stable hemodynamics and combines the advantages of in situ or ex situ standard TVE with hypothermic liver perfusion, without their inherent prolongation of ischemia time and need for venovenous bypass.

Prognostic Impact of Pedicle Clamping during Liver Resection for Colorectal Metastases

Pedicle clamping (PC) during liver resection for colorectal metastases (CRLM) is used to reduce blood loss and allogeneic blood transfusion (ABT). The effect on long-term oncologic outcomes is still under debate. A retrospective analysis of the impact of PC on ABT-demand regarding overall (OS) and recurrence-free survival (RFS) in 336 patients undergoing curative resection for CRLM was carried out. Survival analysis was performed by both univariate and multivariate methods and propensity-score (PS) matching. PC was employed in 75 patients (22%). No increased postoperative morbidity was monitored. While the overall ABT-rate was comparable (35% vs. 37%, p = 0.786), a reduced demand for more than two ABT-units was observed (p = 0.046). PC-patients had better median OS (78 vs. 47 months, p = 0.005) and RFS (36 vs. 23 months, p = 0.006). Multivariate analysis revealed PC as an independent prognostic factor for OS (HR = 0.60; p = 0.009) and RFS (HR = 0.67; p = 0.017). For PC-patients, 1:2 PS-matching (N = 174) showed no differences in the overall ABT-rate compared to no-PC-patients (35% vs. 40%, p = 0.619), but a trend towards reduced transfusion requirement (>2 ABT-units: 9% vs. 21%, p = 0.052; >4 ABT-units: 2% vs. 11%, p = 0.037) and better survival (OS: 78 vs. 44 months, p = 0.088; RFS: 36 vs. 24 months; p = 0.029). Favorable long-term outcomes and lower rates of increased transfusion demand were observed in patients with PC undergoing resection for CRLM. Further prospective evaluation of potential oncologic benefits of PC in these patients may be meaningful.

Complex liver resection under hepatic vascular exclusion and hypothermic perfusion with versus without veno-venous bypass: a comparative study

BACKGROUND

While hypothermic liver perfusion has been shown to improve parenchymal tolerance to complex resections in patients requiring prolonged hepatic vascular exclusion (HVE), the benefit of associated veno-venous bypass (VVB) in this setting remains poorly evaluated.

METHODS

All patients undergoing liver resection requiring HVE and hypothermic liver perfusion for at least 55 min between 2006 and 2017 were retrospectively reviewed. Perioperative outcomes were compared between patients with (VVB+) or without VVB (VVB-).

RESULTS

Twenty-seven patients were analyzed, including 13 VVB+ and 14 VVB-. Median HVE duration was similar in VVB+ and VVB- patients (96 vs. 75 min, respectively). VVB+patients had longer operative time (460 vs. 375 min, p = 0.023) but less blood loss (p = 0.010). Five (19%) patients died postoperatively from liver failure or sepsis, without difference between groups. Postoperative major morbidity rate was similar between VVB+ and VVB- patients (30% vs. 50%, respectively) such as rates of liver failure, haemorrhage, renal insufficiency and sepsis, but VVB- patients experienced more respiratory complications (64% vs. 15%, p = 0.012).

CONCLUSION

During liver resection under HVE and hypothermic liver perfusion, use of VVB allows for reducing blood loss and postoperative respiratory complications. VVB should be recommended in case of liver resection with prolonged HVE.

Progress of liver resection for hepatocellular carcinoma in Taiwan

Taiwan is a well-known endemic area of hepatitis B. Hepatocellular carcinoma (HCC) has consistently been the first or second highest cause of cancer death over the past 20 years. This review article describes the progress of liver resection for HCC in Taiwan in the past half century. The mortality rate for HCC resection was 15-30% in Taiwan in the 1970s. The rate decreased to 8-12% in the early 1990s, and it declined to <1-3% recently. The development of new operative instruments, and surgical techniques, increased knowledge of liver anatomy and pathophysiology after hepatectomy, and more precise patient selection have contributed to this improvement. The use of intermittent hepatic inflow blood occlusion, a restrictive blood transfusion policy and intraoperative ultrasonography, have also led to substantial improvements in resectability and safety for HCC resection in Taiwan. Advances in non-operative modalities for HCC treatment have also helped to improve long-term outcomes of HCC resection. Technical innovations have allowed the application of complex procedures such as mesohepatectomy, unroofing hepatectomy, major portal vein thrombectomy, hepatic vein reconstruction in resection of the cranial part with preservation of the caudal part of the liver, and inferior vena cava and right atrium tumor thrombectomy under cardiopulmonary bypass. In selected patients, including patients with end-stage renal failure, renal graft recipients, patients with portal hypertension, hypersplenic thrombocytopenia and/or associated gastroesophageal varices, octogenarian, ruptured HCC, recurrent HCC and metastatic HCC can also be resected with satisfactory survival benefits. We conclude that the results of liver resection for HCC in Taiwan are improving. The indications for HCC resection continue extending with lower the surgical risks and increasing the long-term survival rate.

In Situ Hypothermic Perfusion of the Liver for Complex Hepatic Resection: Surgical Refinements

INTRODUCTION

While total vascular exclusion (TVE) with veno-venous bypass and hypothermia may be undertaken to increase liver tolerance for complex liver resection, these procedures are still associated with elevated rates of postoperative complications and mortality. In particular, one of the main issues of this strategy is the management of bleeding after declamping, which is enhanced by both hypothermic state and acidosis. To overcome this high risk of morbidity, several technical refinements might be undertaken and here described (with video).

METHODS

All patients, requiring TVE >60 min and liver cooling during hepatectomy, were retrospectively included in this study. Technical key points as (a) patient selection, (b) anesthetic management, (c) two-surgeon's technique, (d) preparation for clamping, (e) veno-venous bypass, (f) cooling of the liver, and (g) parenchymal transection, rewarming, and declamping are described and detailed.

RESULTS

From 2011 to 2013, we included 8 cases of liver resection with TVE, veno-venous bypass, and hypothermia for malignant disease. Due to the technical refinements, median observed overall blood loss of 550 ml (300-900) including 200 ml (50-300) at declamping and transfusion of packed red blood cell (PRBC) units was required in 5 patients with a mean of 1.25 PRBC/patient.

CONCLUSION

The association of TVE, veno-venous bypass, and liver cooling can reduce the time of transection, and blue dye injection and liver rewarming before declamping can reduce blood loss and coagulopathy. Altogether, limited blood loss can be achieved for these complex procedures and may allow to decreasing morbidity.

A New Chemical Compound, NecroX-7, Acts as a Necrosis Modulator by Inhibiting High-Mobility Group Box 1 Protein Release During Massive Ischemia-Reperfusion Injury

BACKGROUND

Necrotic cell death is common in a wide variety of pathologic conditions, including ischemia-reperfusion (IR) injury. The aim of this study was to develop an IR injury-induced hepatic necrosis model in dogs by means of selective left hepatic inflow occlusion and to test the efficacy of a new chemical compound, NecroX-7, against the IR injury-induced hepatic damage.

METHODS

A group of male Beagle dogs received intravenous infusions of either vehicle or different doses of NecroX-7 (1.5, 4.5, or 13 mg/kg) for a 20-minute period before a 90-minute left hepatic inflow occlusion followed by reperfusion.

RESULTS

The gross morphology in the NecroX-7-treated groups after occlusion appeared to be less congested and less swollen than that in vehicle-treated control group. Circulating alanine transaminase and aspartate transaminase levels in the control group were elevated during the course of IR, and were effectively blocked in the 4.5 and 13 mg/kg NecroX-7-treated groups. The serum levels of high-mobility group box 1 protein showed a peak at 8 hours after occlusion in control group, and this elevation was significantly blunted by 4.5 mg/kg NecroX-7 treatment. Histologic analysis showed a marked ischemia or IR injury-induced hepatocytic degenerations, sinusoidal and portal vein congestions, and inflammatory cell infiltrations in the control group, whereas the treatment groups showed significantly diminished histopathology in a dose-dependent manner.

CONCLUSIONS

These results demonstrated that NecroX-7 attenuated the hepatocyte lethality caused by hepatic IR injury in a large animal setting. We conclude that NecroX-7 may provide a wide variety of therapeutic options for IR injury in human patients.

Acute renal injury after partial hepatectomy

Currently, partial hepatectomy is the treatment of choice for a wide variety of liver and biliary conditions. Among the possible complications of partial hepatectomy, acute kidney injury (AKI) should be considered as an important cause of increased morbidity and postoperative mortality. Difficulties in the data analysis related to postoperative AKI after liver resections are mainly due to the multiplicity of factors to be considered in the surgical patients, moreover, there is no consensus of the exact definition of AKI after liver resection in the literature, which hampers comparison and analysis of the scarce data published on the subject. Despite this multiplicity of risk factors for postoperative AKI after partial hepatectomy, there are main factors that clearly contribute to its occurrence. First factor relates to large blood losses with renal hypoperfusion during the operation, second factor relates to the occurrence of post-hepatectomy liver failure with consequent distributive circulatory changes and hepatorenal syndrome. Eventually, patients can have more than one factor contributing to post-operative AKI, and frequently these combinations of acute insults can be aggravated by sepsis or exposure to nephrotoxic drugs.

How much ischemia can the liver tolerate during resection?

The use of vascular inflow occlusion (VIO, also known as the Pringle maneuver) during liver surgery prevents severe blood loss and the need for blood transfusion. The most commonly used technique for VIO entails clamping of the portal triad, which simultaneously occludes the proper hepatic artery and portal vein. Although VIO is an effective technique to reduce intraoperative blood loss, it also inevitably inflicts hepatic ischemia/reperfusion (I/R) injury as a side effect. I/R injury induces formation of reactive oxygen species that cause oxidative stress and cell death, ultimately leading to a sterile inflammatory response that causes hepatocellular damage and liver dysfunction that can result in acute liver failure in most severe cases. Since the duration of ischemia correlates positively with the severity of liver injury, there is a need to find the balance between preventing severe blood loss and inducing liver damage through the use of VIO. Although research on the maximum duration of hepatic ischemia has intensified since the beginning of the 1980s, there still is no consensus on the tolerable upper limit. Based on the available literature, it is concluded that intermittent and continuous VIO can both be used safely when ischemia times do not exceed 120 min. However, intermittent VIO should be the preferred technique in cases that require >120 min duration of ischemia.

The impact of intraoperative vascular occlusion during liver surgery on postoperative peak ALT levels: A systematic review and meta-analysis

BACKGROUND AND AIMS

Intraoperative vascular occlusion techniques during liver surgeries have been performed and refined for decades. However, the impact of these techniques on postoperative peak ALT levels remains uncertain. Thus, we performed a literature review and meta-analysis to determine the impact of intraoperative vascular occlusion during liver surgery on postoperative peak ALT levels.

METHODS

A systematic literature search of the PubMed database was conducted to discover relevant controlled clinical trials. Studies that reported postoperative peak ALT values for both an observation group and a control group were included. The Q statistic and the I(2) index statistic were used to assess heterogeneity. Publication bias was evaluated using Egger's test and Orwin's fail-safe N test.

RESULTS

Of the 281 retrieved articles, 10 articles fulfilled the inclusion criteria. These 10 articles involved 12 randomized controlled trials with a total of 1443 records. The pooled estimation results indicated that intraoperative vascular occlusion significantly elevated postoperative peak ALT levels (test for SMD: Z = 4.09, P < 0.001; 95% CI: 0.59-1.68), with high heterogeneity (I(2) = 93.8%). Subgroup analysis revealed that intermittent inflow occlusion and Pringle's maneuver vascular occlusions may be the potential crucial factors. No obvious publication bias was detected by Egger's test (P = 0.541) or Orwin's fail-safe N test (Nfs0.05 = 2059.19).

CONCLUSIONS

Intraoperative vascular occlusion, especially intermittent inflow occlusion and Pringle's maneuver vascular occlusions, may be a potential risk factor that could lead higher postoperative peak ALT values than non-occlusion procedures for liver surgeries.

Pringle's Maneuver With a Releasable Insulok Band

BACKGROUND

Currently, there are many conventional instruments being applied to perform hepatic inflow control, the Pringle's maneuver, distal to the hepatic hilum during hepatic resections. We wondered if a commonly used Insulok band can be added.

MATERIALS AND METHODS

Insulok band is a plastic tying device molded in one piece with an excellent cam-lock mechanism. We have applied releasable Insulok band to the Pringle's maneuver in 10 partial hepatectomy cases, which are not suitable for application of Chang's needle. After opening the lesser omentum, the band was passed through the Winslow foramen to the lesser sac, and the portal triad was occluded by locking the band. During the intermittent reperfusion period, this Insulok band allowed easy and fast control of hepatic inflow with its simple releasable locking device.

RESULTS

Single inflow block was used on 6 cases while repeated block on 4 cases for partial hepatectomy. The average ischemic time was 15.2 ± 8.2 minutes with an interval of 5 minutes. There was neither procedure-related morbidity nor mortality. No patient had developed postoperative hepatic failure or prolonged liver dysfunction. The efficacy of bleeding control was excellent and the average blood loss during Pringle's maneuver was 6 ± 12.6 mL. Furthermore, locking and unlocking of the Insulok band each took only 5 seconds.

CONCLUSION

Releasable Insulok band is a simpler, faster, cheaper, and safe alternative to the conventional methods for blocking hepatic inflow in Pringle's maneuver, especially in those cases not suitable for using the Chang's needle.

Efficacy and safety of hepatectomy performed with intermittent portal triad clamping with low central venous pressure

Background. This retrospective study was designed to investigate the efficacy and safety of intermittent portal triad clamping (PTC) with low central venous pressure (CVP) in liver resections. Methods. Between January 2007 and August 2013, 115 patients underwent liver resection with intermittent PTC. The patients' data were retrospectively analyzed. Results. There were 58 males and 57 females with a mean age of 55 years (±13.7). Cirrhosis was found in 23 patients. Resections were performed for malignant disease in 62.6% (n = 72) and for benign disease in 37.4% (n = 43). Major hepatectomy was performed in 26 patients (22.4%). Mean liver ischemia period was 27.1 min (±13.9). The mortality rate was 1.7% and the morbidity rate was 22.6%. Cumulative clamping time (t = 3.61, P < 0.001) and operation time (t = 2.38, P < 0.019) were significantly correlated with AST alterations (D-AST). Cumulative clamping time (t = 5.16, P < 0.001) was significantly correlated with D-ALT. Operation time (t = 5.81, P < 0.001) was significantly correlated with D-LDH. Conclusions. Intermittent PTC under low CVP was performed with low morbidity and mortality. Intermittent PTC can be safely applied up to 60 minutes in both normal and impaired livers.

Hepatic pedicle clamping during hepatic resection for colorectal liver metastases: no impact on survival or hepatic recurrence

BACKGROUND

Hepatic pedicle clamping is often used during liver resection. While its use reduces blood loss and transfusion requirements, the long-term effect on survival and recurrence has been debated. This study evaluates the effect of hepatic pedicle clamping [i.e., Pringle maneuver (PM)] on survival and recurrence following hepatic resection for colorectal liver metastasis (CRLM).

METHODS

Patients who underwent R0 resection for CRLM from 1991 to 2004 were identified from a prospectively maintained database. Operative, perioperative, and clinicopathological variables were analyzed. The primary outcomes were disease-free survival (DFS) and liver recurrence (LR). Disease extent was categorized using a well-defined clinical risk score (CRS). Subgroup analysis was performed for patients given preoperative systemic chemotherapy and postoperative pump chemotherapy.

RESULTS

This study included 928 consecutive patients with median follow-up of 8.9 years. PM was utilized in 874 (94%) patients, with median time of 35 min (range 1-181 min). On univariate analysis, only resection type (p<0.001) and tumor number (p=0.002) were associated with use of PM. Younger age (p=0.006), longer operative time (p<0.001), and multiple tumors (p=0.006) were associated with prolonged PM (>60 min). There was no association between DFS, overall survival (OS) or LR and Pringle time. Neither the CRS nor use of neoadjuvant therapy stratified disease-related outcome with respect to use of PM.

CONCLUSIONS

PM was used in most patients undergoing resection for CRLM and did not adversely influence intrahepatic recurrence, DFS, or OS.

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.

Effects of ischemic pre- and postconditioning on HIF-1α, VEGF and TGF-β expression after warm ischemia and reperfusion in the rat liver

Background

Ischemic pre- and postconditioning protects the liver against ischemia/reperfusion injuries. The aim of the present study was to examine how ischemic pre- and postconditioning affects gene expression of hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor A (VEGF-A) and transforming growth factor β (TGF-β) in liver tissue.

Methods

28 rats were randomized into five groups: control; ischemia/reperfusion; ischemic preconditioning (IPC); ischemic postconditioning (IPO); combined IPC and IPO. IPC consisted of 10 min of ischemia and 10 min of reperfusion. IPO consisted of three cycles of 30 sec. reperfusion and 30 sec. of ischemia.

Results

HIF-1α mRNA expression was significantly increased after liver ischemia compared to controls (p = 0.010). HIF-1α mRNA expression was significantly lower in groups subjected to IPC or combined IPC and IPO when compared to the ischemia/reperfusion group (p = 0.002). VEGF-A mRNA expression increased in the ischemia/reperfusion or combined IPC and IPO groups when compared to the control group (p < 0.05).

Conclusion

Ischemic conditioning seems to prevent HIF-1α mRNA induction in the rat liver after ischemia and reperfusion. This suggests that the protective effects of ischemic conditioning do not involve the HIF-1 system. On the other hand, the magnitude of the HIF-1α response might be a marker for the degree of I/R injuries after liver ischemia. Further studies are needed to clarify this issue.

Comparison of major hepatectomy performed under intermittent Pringle maneuver versus continuous Pringle maneuver coupled with in situ hypothermic perfusion

BACKGROUND

The Pringle maneuver (hepatic inflow occlusion), applied intermittently or continuously, carries the risk of inducing ischemic and reperfusion injury. The risk of damage is higher in the latter procedure. Studies have shown that continuous Pringle maneuver coupled with in situ hypothermic perfusion (CPM-HP) circumvents such adversity. However, reports comparing this technique with the intermittent Pringle maneuver (IPM) are lacking. We therefore report our experience with the use of CPM-HP and compare its outcome with that of IPM.

METHODS

We evaluated the outcome of similar sets of patients who had major hepatic resections performed under IPM and CPM-HP. Variables including short-term survival rate (>90 days), complications, operative time, transection time, intraoperative blood loss, postoperative liver functions, and postoperative hospital stay were used to compare the two groups.

RESULTS

Eighteen major hepatectomies were performed with CPM-HP and 16 with IPM. CPM-HP was safely performed in patients with chronic liver disease. Lowering the liver's temperature extends the clamping period to 140 min. Perioperative outcomes including operative time (383.9 ± 89.4 vs. 351.9 ± 70.3 min, p = 0.252), blood loss (225.6 ± 48.4 vs. 351.9 ± 70.3 ml, p = 0.057), postoperative hospital stay, morbidity rate, and the rate of liver functions following resections were comparable for the CPM-HP and IPM groups. There was no mortality. Parenchymal transection time was significantly longer in the CPM-HP group (104.1 ± 20.2 vs. 85.0 ± 15.4 min, p = 0.004)

CONCLUSION

Our findings did not show there to be a significant advantage of CPM-HP over IPM.

Development of a porcine model of post-hepatectomy liver failure

BACKGROUND

The aim of this study was to develop a porcine model of post-operative liver failure (POLF) that could accurately reproduce all the neurological and metabolic parameters of the corresponding clinical syndrome that may develop after extensive liver resections.

METHODS

In our model, we induced POLF by combining extended left hepatectomy and ischemia of the small liver remnant of 150 min duration. Subsequently, the remnant liver parenchyma was reperfused and the animals were closely monitored for 24 h.

MATERIALS

Twelve Landrace pigs (weight 25-30 kg) were randomly assigned in two groups; eight of them constituted the experimental group, in which POLF was induced (POLF group, n = 8), whereas the rest of them (n = 4) were included in the control group (sham laparotomy without establishment of POLF). RESULTS (MEANS ± SD): All POLF animals gradually developed neurological and biochemical signs of liver failure including, among many other parameters, elevated intracranial pressure (24.00 ± 4.69 versus 10.17 ± 0.75, P = 0.004) and ammonia levels (633.00 ± 252.21 versus 51.50 ± 9.49, P = 0.004) compared with controls. Histopathologic evaluation of the liver at the end of the experiment demonstrated diffuse coagulative necrosis and severe architectural distortion of the hepatic parenchyma in all POLF animals.

CONCLUSION

Our surgical technique creates a reproducible porcine model of POLF which can be used to study the pathophysiology and possible therapeutic interventions in this serious complication of extensive hepatectomies.

The safety and efficacy of ablative techniques adjacent to the hepatic vasculature and biliary system

Ablative techniques may provide an alternative to resection in treating awkwardly placed hepatic malignancy adjacent to major vascular and biliary structures. The heat-sink effect may reduce efficacy adjacent to major vascular structures. Vascular occlusion improves efficacy but is associated with increased vascular and biliary complications. The safety and efficacy of ablation in these situations remain to be defined. Further studies comparing both safety and efficacy are needed.

Ischemic preconditioning-induced hyperperfusion correlates with hepatoprotection after liver resection

AIM: To characterize the impact of the Pringle maneuver (PM) and ischemic preconditioning (IP) on total blood supply to the liver following hepatectomies.

METHODS: Sixty one consecutive patients who underwent hepatic resection under inflow occlusion were randomized either to receive PM alone (n = 31) or IP (10 min of ischemia followed by 10 min of reperfusion) prior to PM (n = 30). Quantification of liver perfusion was measured by Doppler probes at the hepatic artery and portal vein at various time points after reperfusion of remnant livers.

RESULTS: Occlusion times of 33 ± 12 min (mean ± SD) and 34 ± 14 min and the extent of resected liver tissue (2.7 segments) were similar in both groups. In controls (PM), on reperfusion of liver remnants for 15 min, portal perfusion markedly decreased by 29% while there was a slight increase of 8% in the arterial blood flow. In contrast, following IP + PM the portal vein flow remained unchanged during reperfusion and a significantly increased arterial blood flow (+56% vs baseline) was observed. In accordance with a better postischemic blood supply of the liver, hepatocellular injury, as measured by alanine aminotransferase (ALT) levels on day 1 was considerably lower in group B compared to group A (247 ± 210 U/I vs 550 ± 650 U/I, P < 0.05). Additionally, ALT levels were significantly correlated to the hepatic artery inflow.

CONCLUSION: IP prevents postischemic flow reduction of the portal vein and simultaneously increases arterial perfusion, suggesting that improved hepatic macrocirculation is a protective mechanism following hepatectomy.

Bioelectrical impedance may predict cell viability during ischemia and reperfusion in rat liver

Ischemia and reperfusion (I/R) injury is a major cause of hepatic failure after liver surgery, but no method could monitor or predict it real-time during surgery. We measured bioelectrical impedance (BEI) and cell viability to assess the usefulness of BEI during I/R in rat liver. A 70% partial liver ischemia model was used. BEI was measured at various frequencies. Adenosine triphosphate (ATP) content, and palmitic acid oxidation rate were measured, and histological changes were observed in order to quantify liver cell viability. BEI changed significantly during ischemia at low frequency. In the ischemia group, BEI increased gradually during 60 min of ischemia and had a tendency to plateau thereafter. The ATP content decreased below 20% of the baseline level. In the I/R group, BEI recovered to near baseline level. After 24 hr of reperfusion, the ATP contents decreased to below 50% in 30, 60 and 120 min of ischemia and the palmitic acid metabolic rates decreased to 91%, 78%, and 74%, respectively, compared with normal liver. BEI may be a good tool for monitoring I/R during liver surgery. The liver is relatively tolerant to ischemia, however after reperfusion, liver cells may be damaged depending upon the duration of ischemia.

Topic liver hypothermia and ischemic preconditioning: a new model of ischemia and reperfusion in rats

PURPOSE: Evaluation of the Mean Arterial Pressure (MAP) and body temperature changes in a new model of liver ischemia-reperfusion applying topical Hypothermia and Ischemic Preconditioning (IPC). METHODS: Rats (n= 32) were divided in 5 groups: Control (C), Normothermic Ischemia (NI), Ischemic Preconditioning (IPC), Hypothermia 26°C plus IPC (H+IPC) and Hypothermia 26°C (H). MAP and body temperature were recorded at 30 minutes intervals throughout the entire experiment. The study groups underwent 90 minutes partial hepatic ischemia followed by 120 minutes of reperfusion. The median and lateral left lobes were isolated and topical 26°C hypothermia was induced by superfusion of cooled saline solution in H+IPC and H groups. A 10 minutes protocol of ischemia and reperfusion was applied in the IPC and H+IPC groups before the major ischemic insult. RESULTS: There was no significant difference in MAP and body temperature means between the groups throughout the experiments. CONCLUSION: The present model allows the induction of topical hepatic hypothermia associated or not to IPC. New studies to evaluate the possible synergistic effects of these tools can be reproduced without significant changes in macrohemodynamics and body temperature, or in other words, under stable conditions.

F2-isoprostanes and 2-arachidonylglycerol as biomarkers of lipid peroxidation in pigs with hepatic ischemia/reperfusion injury

BACKGROUND

In the present study, we examined the changes of F(2)-isoprostanes (non-cyclooxygenase-derived prostanoids), endocannabinoids (2-arachidonylglycerol; 2-AG, arachidoylethanolamide; AEA), and malondialdehyde (MDA: a conventional index of lipid peroxidation) in a porcine warm hepatic ischemia/reperfusion (I/R) model to evaluate the usefulness of each parameter as a marker of lipid peroxidation.

METHODS

Five female pigs weighing 20 to 22 kg were used in this experiment. Total liver ischemia was achieved by clamping the hepatic pedicle. To prevent splanchnic congestion during occlusion of the portal vein, a portocaval shunt was created with a Dacron graft. After 90 min of ischemia, the liver was reperfused for 120 min. We measured the plasma levels of four markers (F(2)-isoprostanes, 2-AG, AEA, and MDA) from a viewpoint of whether it is useful as a sensitive marker of lipid peroxidation.

RESULTS

Based on statistical analysis using repeated-measures ANOVA, F(2)-isoprostanes demonstrated the most significant changes and were considered to be a highly sensitive marker (P = 0.0001). 2-AG showed less prominent but significant changes (P = 0.0286), followed by MDA (P = 0.0310). However, AEA did not show statistically significant changes over time. The pattern of change in the serum transaminase levels, a classic marker of liver damage, as well as the histologic changes, resembled the profile of F(2)-isoprostanes, 2-AG, and MDA.

CONCLUSIONS

F(2)-isoprostanes and 2-AG may be useful as markers of oxidative stress in hepatic I/R injury.

Impact of pedicle clamping in pediatric liver resection

BACKGROUND

Vascular clamping techniques are commonly used but so far the impact on pediatric liver surgery has not been investigated. The purpose of this study was to analyze pedicle clamping during pediatric liver resection in terms of hepato-cellular injury and blood loss.

METHODS

Sixty-seven children undergoing liver resection were analyzed retrospectively. Vascular clamping was used in 28 cases (PC group), in 39 the resection was performed without clamping (NPC group). Major hepatectomies (resection of more than three segments) were carried out in 88%, minor hepatectomies (resection of three and less segments) in 12% of patients. Twenty-six children underwent extended liver resection. Patient data, liver function tests (LFTs) and blood loss were analyzed statistically.

RESULTS

There were no significant differences in patient preoperative and postoperative data and LFTs between the groups. Within the NPC group the amount of administered fresh frozen plasma (FFP) in total and per kilogram (FFP/kg) was significantly higher (p=0.023 and 0.028) than in the PC group. For patients with extended liver resection, operation times were significantly longer (p=0.016) in the group without vascular clamping (NPCext). In the NPCext group significantly more children required packed red cells, FFP and FFP/kg. LFTs showed no significant differences in all children regardless of vascular clamping.

CONCLUSIONS

For children undergoing liver resection, vascular clamping offers a blood saving surgical technique. Postoperative LFTs were not statistically different, regardless of vascular clamping. Pedicle clamping proved to be a safe method, not associated with an increase in perioperative complications.

Techniques for liver resection: a review

Improvement in surgical outcomes of liver resection has been achieved in the past decade. Among other factors, a gradual change of technology platforms and refinement of surgical techniques have played significant roles. In this review, the various surgical approaches, operative techniques, operative instruments, and adjunctive measures as applied in liver resection are described, along with discussion of the pros and cons of each of these attributes. A brief description of laparoscopic liver resection is also included to address this important and emerging area in liver surgery.

Extended right trisegmentectomy using in situ hypothermic perfusion with modified HTK solution for a large intrahepatic cholangiocarcinoma

The technique of right hepatic trisegmentectomy has been standardized for large tumors that involve the right lobe and extend into the medial segment of the left lobe. However, these tumors are deemed unresectable if they encroach across the falciform ligament into the left lateral segment. We report the technique of extended right trisegmentectomy in a patient with a large intrahepatic cholangiocarcinoma that involved the right lobe of the liver and extended into the medial and lateral segments of the left lobe. The resection was performed by using total hepatic vascular isolation and in situ hypothermic perfusion with modified histidine-tryptophan-ketoglutarate (HTK) solution into the left lateral segment. The biliary enteric anastomosis was constructed using a double hepaticojejunostomy to Segments II and III bile ducts. The procedure allowed safe parenchymal dissection with preservation of the blood supply to Segments II and III. Furthermore, in situ hypothermic perfusion protected the remnant liver from the deleterious effects of warm ischemia during parenchymal dissection and facilitated postoperative recovery. To the best of our knowledge, this is the first report of extended right trisegmentectomy for the treatment of intrahepatic cholangiocarcinoma in the Western literature.

Surgical treatment of liver metastases from colorectal cancer in elderly patients

INTRODUCTION

The liver is the most frequent site of liver metastases (LM) from colorectal cancer. Because of short life expectancies and improved nonoperative modalities, the role of liver resection in elderly patients with LM is unclear.

METHODS

During a 15-year period, 197 patients underwent liver resection for colorectal metastases. This study was designed to compare morbidity, mortality, and long-term outcome after hepatic resection in patients aged 70 years and older and in patients younger than 70. According to the age at the time of operation, patients were divided into two groups. Group A included patients aged 70 years or older and group B included younger patients.

RESULTS

The clinical and pathologic parameters of the two groups were compared and tested as factors affecting early and long-term outcomes after resection. A modified oncologic clinical risk score (CRS) was tested on this series of patients. Overall morbidity was 16.3% (group A 20.7% vs group B 14.6%; P=0.18). Hospital mortality was 3% (5.7% in group A and 2.1% in group B; P=0.19). Actuarial 5 years survival were 30% in group A and 38% in group B (P=ns).

DISCUSSION

The presence of more than three Fong's CRS parameters and microscopic involvement of resectional margin directly affected survival. Under meticulous preoperative assessment and postoperative care, liver resection for LM is justified in patients over 70 years of age; age by itself may not be a controindication to surgery.

Portal Triad Occlusion Induces Endotoxin Tolerance: Role of Portal Congestion

BACKGROUND

Portal triad occlusion (PTO) causes portal congestion and damages the intestinal mucosa, which is associated with portal endotoxemia. However, administration of a sublethal dose of endotoxin results in resistance to its toxic activities. We tested the hypothesis that portal congestion due to PTO induces endotoxin tolerance.

MATERIALS AND METHODS

Rats were subjected to PTO for 15 min. In Group 1, male rats underwent laparotomy and, 48 h after the surgery, a lethal dose of Escherichia coli lipopolysaccharide was administered. In Group 2, rats were subjected to PTO for 15 min. Then a lethal dose of LPS was administered 48 h after surgery. Group 3 was treated the same as Group 2, except that PTO was performed with portosystemic shunt. Group 4 was also treated same as Group 2, except that rats received polymixin B and neomycin by gavage to eliminate intestinal luminal bacteria before PTO. Survival was examined after the administration of a lethal dose of LPS. Changes in plasma levels of cytokine are also measured after the administration of LPS. The portal endotoxin level in each group after PTO was measured.

RESULTS

On survival test, only rats in Group 2 and Group 4 showed significantly higher survival rates. The portal endotoxin level was significantly elevated only in Group 2. The elevation of plasma cytokine levels (IL-6, TNF-alpha) and NO production (NO(2)(-)/NO(3)(-)) in Groups 2 and 4 were inhibited compare to those in Groups 1 and 3.

CONCLUSIONS

PTO induced LPS tolerance possibly due to portal congestion and subsequent visceral congestion.

Portal triad clamping (TC) or hepatic vascular exclusion (VE) for major liver resection after prolonged neoadjuvant chemotherapy? A case-matched study in 60 patients

BACKGROUND

Prolonged systemic preoperative chemotherapy induces pathologic changes in liver parenchyma. The consequences of vascular occlusion on liver submitted to prolonged preoperative systemic chemotherapy are not known. The aim of this case-matched study was to assess which method of vascular occlusion is most appropriate for major liver resection in patients who have undergone prolonged preoperative systemic chemotherapy.

METHODS

Among 305 patients who had liver resection for colorectal metastases from 1998 to 2003, 28 underwent major liver resections under portal triad clamping after more than 6 cycles of preoperative chemotherapy (TC group). These 28 patients were compared with 32 patients matched for age, sex, ASA status, number of liver metastases, type of liver resection, and type of preoperative chemotherapy, but who had major liver resection under hepatic vascular exclusion after more than 6 cycles of preoperative chemotherapy (VE group).

RESULTS

There was no postoperative mortality. The morbidity rate was 18% after TC and 43% after VE (P = 0.044). Pulmonary complication rate was greater after VE (31% vs 3%, P = 0.017). The transfusion rate was 50% in the TC group and 40% in the VE group (P = 0.482). Postoperative changes of liver function tests were comparable in the two groups except for the prothrombin time, which was more prolonged from day 1 (P = 0.003) to day 5 (P = 0.04) after VE.

CONCLUSION

Vascular occlusion can be used with no mortality and acceptable morbidity for major liver resection after prolonged preoperative chemotherapy. TC should be preferred to VE, permitted by the location of the neoplasm.

Advantage of ischemic preconditioning for hepatic resection in pigs

BACKGROUND

Ischemic preconditioning (IP) and intermittent inflow occlusion (IO) have provided beneficial outcomes in hepatic resection. However, comparison of these two procedures against warm hepatic ischemia-reperfusion injury has not been studied enough.

MATERIALS AND METHODS

Pigs that had undergone 65% hepatectomy were subjected to Control (120 min continuous ischemia, n = 6), IP (10 min ischemia and 10 min reperfusion, followed by 120 min continuous ischemia, n = 6), and IO (120 min ischemia in the form of eight successive periods of 15 min ischemia and 5 min reperfusion, n = 6). We evaluated hepatocyte injury by aspartate aminotransferase, lactate dehydrogenase and hepaplastin test, hepatic microcirculation by hepatic tissue blood flow (HTBF) and endothelin (ET)-1, inflammatory response by tumor necrosis factor-alpha (TNF-alpha), and histopathology after reperfusion.

RESULTS

IP prevented hepatocyte injury, HTBF disturbance, and hepatocyte necrosis in histopathology as well as IO. These two groups showed significantly better outcomes than Control. IP produced significantly less ET-1 and TNF-alpha than IO.

CONCLUSIONS

IP ameliorated hepatic warm ischemia-reperfusion injury. Furthermore, IP gained more advantages in preventing chemokine production such as ET-1 and inflammatory response over IO. IP could take the place of IO for hepatectomy.

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.

Liver resection for hepatocellular carcinoma on cirrhosis: analysis of mortality, morbidity and survival—a European single center experience

AIMS

To evaluate short- and long-term results of liver resections and prognostic factors in cirrhotic patients with hepatocellular carcinoma.

STUDY DESIGN

A single-unit, retrospective study analyzing 216 patients with histologically confirmed cirrhosis who underwent hepatic resection for hepatocellular carcinoma. All clinico-pathologic and follow-up data were collected prospectively.

RESULTS

Child A patients had a significantly lower in-hospital mortality rate compared to Child B-C: 4.7 vs 21.3% (p=0.0003). Overall morbidity rate was 38.4%; multiple logistic regression analysis identified liver function, hepatic pedicle clamping time, number of nodes and transfusion rate as independent predictors for post-operative complications. Overall and disease-free 5-year survival rates were 34.1 and 25.2%. Multivariate analysis showed that Child A, radical resection, tumour size < or =5 cm and, absence of vascular invasion were independent prognostic factors for long-term survival. No significant differences in overall and disease-free survival were found according to the type of resection (anatomic vs non-anatomic).

CONCLUSIONS

Patients with preserved liver function and small-size, single-node hepatocellular carcinomas are the best candidates for hepatic resection.

Avaliação da lesão isquêmica normotérmica do fígado: papel da oclusão do ducto biliar principal e da N-acetilcisteína

OBJETIVO: Estudar o efeito da N-acetilcisteína (NAC) na isquemia hepática. MÉTODO: Trinta e oito ratos machos EPM-1 Wistar foram distribuídos em quatro grupos. Nos Grupos 1 e 2 foi realizado 30 min de clampeamento do hilo hepático, e nos Grupos 3 e 4 os animais foram submetidos a 30 minutos de isquemia sem clampleamento do ducto biliar. Os animais dos Grupos 2 e 4 receberam 150mg.Kg-1 de NAC, endovenoso, 15 minutos antes do procedimento. Colheu-se sangue antes do procedimento e após o clampeamento do pedículo para a dosagem enzimática. Amostras de fígado foram coletadas para dosagem de glutationa, microscopia óptica e eletrônica. No estudo estatístico aplicaram-se testes não paramétricos, p < 0,05. RESULTADOS: O aumento das enzimas foi menor quando se administrou NAC, sendo semelhante na ausência do clampeamento da via biliar. À microscopia óptica houve diferença significante dos grupos S/NAC X C/NAC, mostrando que o grupo C/NAC manteve a arquitetura do parênquima durante a isquemia, independente do clampeamento do ducto biliar. Na microscopia eletrônica os grupos C/NAC e os sem clampeamento do ducto biliar apresentaram arquitetura celular preservada. A NAC não alterou a relação de glutationa reduzida/ glutationa oxidada (GSH/GSSG). CONCLUSÕES: A NAC é capaz de proteger o parênquima hepático durante a isquemia normotérmica e propõe-se que o mecanismo seja por reação direta da NAC com o óxido nítrico (NO).

In situ hypothermic perfusion of the liver versus standard total vascular exclusion for complex liver resection

SUMMARY BACKGROUND DATA

We compare the results of liver resection performed under in situ hypothermic perfusion versus standard total vascular exclusion (TVE) of the liver <60 minutes and > or =60 minutes in terms of liver tolerance, liver and renal functions, postoperative morbidity, and mortality. The safe duration of TVE is still debated. Promising results have been reported following TVE associated with hypothermic perfusion of the liver with durations of up to several hours. The 2 techniques have not been compared so far.

METHODS

The study population includes 69 consecutive liver resections under TVE <60 minutes (group TVE<60', 33 patients), > or =60 minutes (group TVE> or =60', 16 patients), and in situ hypothermic perfusion (group TVEHYOPOTH, 20 patients). Liver tolerance (peaks of transaminases), liver and kidney function (peak of bilirubin, minimum prothrombin time, and peak of creatinine), morbidity, and in-hospital mortality were compared within the 3 groups.

RESULTS

The postoperative peaks of aspartate aminotransferase (IU/L) and alanine aminotransferase (IU/L) were significantly lower (P[r] < 0.05) in group TVE HYPOTH (450 +/- 298 IU/L and 390 +/- 391 IU/L) compared with the groups TVE<60' (1000 +/- 808; 853 +/- 743) and TVE> or =60' (1519 +/- 962; 1033 +/- 861). In the group TVEHYPOTH, the peaks of bilirubin (micromol/L) (84 +/- 31), creatinine (micromol/L) (75 +/- 22), and the number of complications per patient (1.2 +/- 0.9) were comparable to those of the group TVE<60' (80 +/- 111; 109 +/- 77; and 0.8 +/- 1.1 respectively) and significantly lower to those of the group TVE> or =60' (196 +/- 173; 176 +/- 176, and 2.6 +/- 1.8). In-hospital mortality rates were 1 in 33, 2 in 16, and 0 in 20 for the groups TVE<60', TVE> or =60', and TVEHYOPOTH, respectively, and were comparable. On multivariate analysis, the size of the tumor, portal vein embolization, and a planned vascular reconstruction were significantly predictive of TVE > or =60 minutes.

CONCLUSIONS

Compared with standard TVE of any duration, hypothermic perfusion of the liver is associated with a better tolerance to ischemia. In addition, compared with TVE > or =60 minutes, it is associated with better postoperative liver and renal functions and a lower morbidity. Predictive factors for TVE > or =60 minutes may help to indicate hypothermic perfusion of the liver.

Glutathione protects the rat liver against reperfusion injury after prolonged warm ischemia

OBJECTIVE

To evaluate the potential of postischemic intravenous infusion of the endogenous antioxidant glutathione (GSH) to protect the liver from reperfusion injury following prolonged warm ischemia.

BACKGROUND DATA

The release of reactive oxygen species (ROS) by activated Kupffer cells (KC) and leukocytes causes reperfusion injury of the liver after warm ischemia. Therefore, safe and cost-effective antioxidant strategies would appear a promising approach to prevent hepatic reperfusion injury during liver resection, but need to be developed.

METHODS

Livers of male Lewis rats were subjected to 60, 90, or 120 minutes of normothermic ischemia. During a 120 minutes reperfusion period either GSH (50, 100 or 200 micromol/h/kg; n= 6-8) or saline (n= 8) was continuously administered via the jugular vein.

RESULTS

Postischemic GSH treatment significantly prevented necrotic injury to hepatocytes as indicated by a 50-60% reduction of serum ALT and AST. After 1 hour of ischemia and 2 hours of reperfusion apoptotic hepatocytes were rare (0.50 +/- 0.10%; mean +/- SD) and not different in GSH-treated animals (0.65 +/- 0.20%). GSH (200 micromol GSH/h/kg) improved survival following 2 hours of ischemia (6 of 9 versus 3 of 9 rats; P < 0.05). Intravital fluorescence microscopy revealed a nearly complete restoration of sinusoidal blood flow. This was paralleled by a reduction of leukocyte adherence to sinusoids and postsinusoidal venules. Intravenous GSH administration resulted in a 10- to 40-fold increase of plasma GSH levels, whereas intracellular GSH contents were unaffected. Plasma concentrations of oxidized glutathione (GSSG) increased up to 5-fold in GSH-treated animals suggesting counteraction of the vascular oxidant stress produced by activated KC.

CONCLUSIONS

Intravenous GSH administration during reperfusion of ischemic livers prevents reperfusion injury in rats. Because GSH is well tolerable also in man, this novel approach could be introduced to human liver surgery.

Bacterial translocation, endotoxaemia and apoptosis following Pringle manoeuvre in rats

BACKGROUND

Intraoperative occlusion of the hepatoduodenal ligament (Pringle manoeuvre (Pm)) is often employed for the reduction of blood loss during liver surgery. No data exist to date on the effects of Pm on mucosal barrier dysfunction, systemic bacterial translocation (BT), endotoxaemia and apoptosis.

MATERIALS AND METHODS

Sixty-five male Wistar rats in three groups: I (n=25) controls, II (n=20) sham operation, III (n=20) occlusion of the hepatoduodenal ligament (Pm). Tissue samples from mesenteric lymph nodes (MLNs), liver, lungs and spleen were analysed after 30 min and at 24 h. Endotoxin was measured in portal and aortic blood and routine haematological and biochemical parameters were measured before and after Pm.

RESULTS

No differences were found in the blood parameters before and after Pm, but a significant increase in contaminated MLNs and liver was noted. All cultured bacteria were enteric in origin. Portal and aortic endotoxin were significantly increased. Overall the ileal architecture remained intact in all specimens studied and no significant pathology was observed. The ABC increased after Pm significantly (P<0.01).

CONCLUSION

Normothermic Pm of 30 min duration results in immediate and delayed gut barrier failure by significantly increasing BT and endotoxaemia which might be attributed to portal stasis leading to intestinal congestion as well as temporary liver ischaemia. Apoptosis increased significantly 30 min after performing the Pm.

Hemostasis in liver resection surgery

Although patients with liver tumors are considered as challenging by hepatic surgeons, advances in liver resection procedures mean that virtually no liver tumor should be considered as unresectable. Newer techniques, such as in situ hypothermic perfusion, the "ante situm technique," and ex vivo liver resection have been recently introduced. The aim of these techniques is to provide a bloodless field and a prolonged and more precise dissection. The use of recombinant factor VIIa (rFVIIa), a hemostatic agent previously developed for bleed management in patients with hemophilia and inhibitors, has recently been investigated as a means of reducing red blood cell transfusion requirements during major liver surgery. This paper reviews details of this clinical trial, as well as current and future methods to manage hemostasis during liver resection surgery.

Selective hepatic vascular exclusion versus Pringle maneuver in major liver resections: prospective study

Selective hepatic vascular exclusion (SHVE) and the Pringle maneuver are two methods used to control bleeding during hepatectomy. They are compared in a prospective randomized study, where 110 patients undergoing major liver resection were randomly allocated to the SHVE group or the Pringle group. Data regarding the intraoperative and postoperative courses of the patients are analyzed. Intraoperative blood loss and transfusion requirements were significantly decreased in the SHVE group, and postoperative liver function was better in that group. Although there was no difference between the two groups regarding the postoperative complications rate, patients offered the Pringle maneuver had a significantly longer hospital stay. The application of SHVE did not prolong the warm ischemia time or the total operating time. It is evident from the present study that SHVE performed by experienced surgeons is as safe as the Pringle maneuver and is well tolerated by the patients. It is much more effective than the Pringle maneuver for controlling intraoperative bleeding, and it is associated with better postoperative liver function and shorter hospital stay.

Total vascular exclusion technique for resection of hepatocellular carcinoma

AIM: To improve the low resection rate, poor prognosis and to control the massive hemorrhage during operation, total vascular exclusion (TVE) technique was used in hepatectomies of advanced and complicated hepatocellular carcinomas (HCCs).

METHODS: Five hundred and thirty patients with HCCs were admitted in our hospital. They were divided into TVE technique group (group A: n = 78), Pringle maneuver method group (group B: n = 176) and unresectable group (group C: n = 276). The clinical, operative, pathological parameters and outcome of the patients were statistically evaluated.

RESULTS: Group A had a significantly higher resection rate than group B (accounting for 47.92% and 33.21% respectively). There was no significant difference in blood loss, blood transfusion and perioperative mortality between groups A and B. Both groups had the similar median disease free survival time (14.6 vs 16.3 months) and 1 year survival rate (92.9% vs 95.5%). The TVE group had a medial survival time of 40.5 months and its 5-year survival rate was 34.6%.

CONCLUSION: As compared with Pringle maneuver method, the total vascular exclusion is a safe and effective technique to increase the total resection rate of advanced and complicated HCCs.

The main indications and techniques for vascular exclusion of the liver

BACKGROUND: The purpose of vascular clamping during the course of liver resection is to reduce bleeding and subsequent complications. AIM: To show both step-by-step surgical techniques for vascular exclusion of the liver and their indications. METHODS: It is described the following techniques: clamping of the hepatic pedicle, ''Pringle'' maneuver; intermittent clamping of the hepatic pedicle; intermittent vascular exclusion of the liver, without vena cava clamping, and hepatic vascular exclusion with vena cava clamping. Also metabolic and homodynamic consequences as well as the technical failure of the application of each of them are discussed. CONCLUSIONS: The choice of technique to use for clamping during hepatectomy depends on the surgeon's judgment. Dogmatic or systematic attitude, is prejudiciable for the patient and liver surgeon must be able to use all kinds of clamping.

Lesion progression with time and the effect of vascular occlusion following radiofrequency ablation of the liver

BACKGROUND

The effectiveness of radiofrequency ablation (RFA) under selective vascular occlusion and its effects on architecture and viability of normal liver parenchyma was studied in a porcine model.

METHODS

RFA was applied in the liver under general anaesthesia in 18 pigs. Six animals were killed immediately after the procedure and 12 at 24 h. RFA was performed sequentially under four conditions: (1) without vascular occlusion, (2) during occlusion of the hepatic artery, (3) during occlusion of the portal vein and (4) during occlusion of the hepatic artery and portal vein. Liver biopsies from the treated area were stained for conventional histological examination, reduced nicotinamide adenine dinucleotide diaphorase and 5'-nucleotidase activity.

RESULTS

Vascular occlusion significantly increased the size of the coagulation centre after RFA. Combined portal venous and arterial occlusion had no additional effect on lesion size compared with venous or arterial occlusion alone. After 24 h, deterioration of viability was observed in the parenchyma up to 3 cm from the coagulated area.

CONCLUSION

The efficacy of RFA in liver increases with occlusion of the portal vein or hepatic artery. The extent of secondary heat-induced necrosis in liver parenchyma should be considered for determination of the final size of the ablated area.

Prospective randomized study of steroids in the prevention of ischaemic injury during hepatic resection with pedicle clamping

BACKGROUND

The major drawback of hepatic pedicle clamping is ischaemia-reperfusion injury with impairment of liver function. Perioperative steroid administration has been advocated to reduce liver damage. The aim of this prospective, randomized study was to determine whether steroid administration can reduce liver injury and improve short-term outcome.

METHODS

Fifty-three patients undergoing liver resection were randomized to a steroid group (group 1) or to a control group (group 2); patients in group 1 received methylprednisolone 30 mg/kg 30 min before liver resection whereas those in group 2 did not. Serum levels of interleukin (IL) 6, total bilirubin, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and prothrombin time (PT) were measured. Length of stay, and type and number of complications were recorded.

RESULTS

Serum IL-6 levels were significantly lower in the steroid group than in the control group 24 h after surgery. Steroid administration significantly modified AST, ALT and PT levels only in patients with chronic liver disease. Overall and lung-related morbidity were not significantly different between the two groups.

CONCLUSIONS

Steroid administration suppresses serum IL-6 levels, but has no effect on short-term outcome.

Hemodynamic and hormonal responses to the sudden interruption of caval flow: insights from a prospective study of hepatic vascular exclusion during major liver resections

Hepatic vascular exclusion (HVE) combines portal triad clamping and occlusion of the inferior vena cava. Although HVE has been performed for major liver resections during the last 2 decades, little is known about the mechanisms that explain its satisfactory hemodynamic tolerance. Consequently, we performed a comprehensive study of both hemodynamic and hormone responses to HVE. Twenty-two patients who underwent liver resection for secondary tumors developed in noncirrhotic livers were prospectively studied. Heart rate, arterial blood pressure, pulmonary artery pressure, mixed venous saturation, cardiac output, and left ventricular dimensions determined by transesophageal echocardiography were monitored in HVE patients. Blood concentrations of arginine vasopressin (AVP), epinephrine, norepinephrine, dopamine, and atrial natriuretic peptide and plasma renin activity (PRA) were measured before clamping; 5, 15, and 30 min after clamping; and 15 min after unclamping. Hemodynamic response to HVE was characterized by a significant (P < 0.05) decrease in left ventricular dimensions, fractional area change, and pulmonary artery pressure. We also observed a marked decrease in cardiac output (50%) and an increase in heart rate and systemic vascular resistance. After unclamping, there was peripheral vasodilation, assessed by a significant decrease in systemic vascular resistance from the preclamping value to unclamping. An acute and sustained increase in AVP and norepinephrine that returned to baseline after unclamping and the absence of modification in PRA concentrations were noted. The marked decrease in venous return that characterizes HVE is compensated for by an increase in vascular resistance secondary to an important activation of the AVP and sympathetic systems. The PRA system does not play an important role in maintaining arterial blood pressure during HVE.

IMPLICATIONS

Hemodynamic and hormonal responses to the acute interruption of caval venous return to the heart were investigated in patients undergoing liver resection with hepatic vascular exclusion. A compensatory role for arginine vasopressin and sympathetic systems that provoked increased vascular resistance was demonstrated.

Continuing Experience with Liver Resection and Vena Cava Reconstruction using Cardiopulmonary Bypass and Hypothermic Circulatory Arrest

When the suprahepatic vena cava or the hepatic vein confluence with the inferior vena cava (IVC) is obscured by tumor or a clot in the IVC extends above the liver, cross-clamping the IVC during liver or retroperitoneal resection is hazardous. This report describes a 10-year experience with ten patients who had liver (seven) or retroperitoneal (three) resections with vena cava reconstruction using cardiopulmonary bypass and hypothermic circulatory arrest. There were no perioperative deaths. Morbidity consisted of prolonged bile leak (one), pulmonary embolism (one), and stroke (one). Control of the liver was secured in six of seven patients who had a liver resection. There were three significant advantages to this technique. First, the median sternotomy provided superior exposure to the suprahepatic IVC. Second, the bypass technique avoided the risks of hemodynamic instability and prevented air embolism and sudden uncontrolled hemorrhage incurred by resection or IVC cross-clamping. Third, hypothermia provided a method of protection for residual liver function especially in the face of chronic liver disease induced by infection or chemotherapy.

Liver resections with or without pedicle clamping

BACKGROUND

Decreasing operative bleeding during liver resection, and thus extent of transfusions, has become a main criterion to evaluate operative results of hepatectomies. Hepatic pedicle clamping (HPC) is widely used for this purpose. The aim of the study was to evaluate safety, efficacy, technique, and contraindications of HPC during liver resections, comparing results of resections performed with or without HPC.

METHODS

Data from 245 liver resections were analyzed. In all, 125 resections were performed with HPC (group A), continuous in 100 cases and intermittent in 25 cases. The average duration of ischemia in group A was 39 +/- 20 minutes (range 7 to 107). In 20 cases (16%) ischemia was prolonged for 60 minutes or more. A total of 120 resections were performed without HPC (group B). Major resections were 53.6% in group A (67 cases) and 38.3% in group B (46 cases). Cirrhosis was present in 36 cases, 19 in group A and 17 in group B.

RESULTS

Operative mortality was nil. Postoperative mortality was 2.9%, morbidity 22.4%. Percentage of transfused cases (34.4% versus 60.0%; P <0.001) and number of blood units per transfused case (2 +/- 1 versus 4 +/- 3; P <0.001) were lower in group A versus group B. Similar figures were found by considering only major resections. Postoperative blood chemistries did not show important differences between the two groups, and postoperative alterations were related more to extent and complexity of the operation than to length of HPC.

CONCLUSIONS

HPC during liver resection is a safe and effective technique. This is demonstrated in a context where HPC is used continuously in most cases, intermittently in cases with impaired liver function and for more prolonged ischemia, and avoided in cases with limited bleeding, jaundice, and simultaneous bowel anastomoses.

Utilização das hepatectomias centrais nas cirurgias hepatobiliares

O tratamento das doenças hepatobiliares através de hepatectomias centrais tem sido um dos desafios técnicos mais importantes para a cirurgia neste final de século. Embora diversas técnicas tenham sido utilizadas nas últimas décadas, só recentemente estas têm sido executadas com segurança, diminuindo drasticamente as taxas de morbi-mortalidade, e com isso propiciando resultados favoráveis no tratamento das diferentes afecções hepáticas. Quer o figado apresente-se ou não com hepatopatia crônica, a integração de equipes multidisciplinares afeitas a este tipo de cirurgia e de patologia, permitiu que ressecções complexas fossem realizadas. Com o princípio de manter massa e função hepatocitária remanescente viáveis, o estudo morfológico e funcional do fígado no pré-operatório impõe que técnicas de transplante de segmentos hepáticos sejam freqüentemente utilizadas, seja na reconstrução vascular, seja na redução e conservação de massa hepática. Desta maneira, a ressecção de qualquer parte do fígado com o mínimo de utilização de derivados sangüíneos tem se mostrado factível através do conhecimento apurado da anatomia hepática e da utilização de ecografia transoperatória. Deste trabalho de revisão de diferentes técnicas de hepatectomias centrais são apresentadas, discutidas as indicações e detalhes cirúrgicos de cada uma delas.

Recent advances in hepatic resection

Hepatic surgery has emerged over the last three decades and has proven to be a safe and effective treatment for primary and secondary malignancies, as well as for benign diseases of the liver. During the past 10 years, several major advances have been made in 1) surgical technique with the advent of portal pedicle ligation maneuvers and the implementation of mechanical staplers, 2) intraoperative management with the development of low central venous pressure anesthesia, and 3) surgical technology with the innovation of laparoscopy for staging of patients with cancer and performing minimally invasive liver resection. We present a summary of our experience with these advances.

[Selective use of vascular clamps in major hepatectomy]

OBJECTIVE

To report the results of a selective use of vascular occlusions in major hepatectomies according to the size and location of the hepatic lesion.

BACKGROUND

Total vascular exclusion (TVE) and portal triad clamping (PTC) ensure efficient hemostatic effect but lead to warm ischemia of the liver. Lobar vascular occlusion (LVO) avoids warm ischemia of the remnant liver but could result in increased blood loss.

PATIENTS AND METHODS

Sixty consecutive major hepatectomies were studied. TVE was applied in 22 patients with large lesions (= 10 cm) or lesions with connections to the major hepatic veins or inferior vena cava. PTC (n = 15) and LVO (n = 23) were applied in remaining cases.

RESULTS

Clamping method was efficient in 87%, 93% and 100% for LVO, PTC and TVE, respectively. Median blood transfusions were 0.3 and 2 units for LVO, PTC and TVE, respectively. Postoperative aminotransferase peak value was significantly lower after LVO than after PTC or TVE, while those peaks were not statistically different with these latter two methods. Postoperative prothrombin time fall value was identical in the three groups. Mortality was 3.3% (2/60) and was not influenced by the type of clamping, but both deaths and most complications occurred in patients with abnormal underlying liver parenchyma.

CONCLUSION

Provided that adequate techniques are used, the need for blood transfusions is more dependent on the characteristics of the resected tumor than on the type of clamping used. Total vascular exclusion does not create more ischemic injury to the liver than portal triad clamping and it should be recommended for the resection of large or strategically located tumors. Other tumors can be resected in more than 80% of the cases with LVO, thus avoiding ischemia to the remnant liver. With the control of hemorrhage, pathology of underlying liver parenchyma has emerged as the main prognostic factor in major liver resections.