Effect of prior portosystemic shunt on early hepatic hemodynamics and sinusoids following 84% hepatectomy in dogs

Portocaval shunt can optimize transhepatic flow following extended hepatectomy: a short-term study in a porcine model

The aim of this study was to evaluate whether the portocaval shunt (PCS) corrects these unwanted changes in transhepatic flow after extended hepatectomy (EH). Forty female Landrace pigs were divided into two main groups: (A) EH (75%) and (B) no EH. Group A was divided into 3 subgroups: (A1) EH without PCS; (A2) EH with side-to-side PCS; and (A3) EH with end-to-side PCS. Group B was divided into 2 subgroups: (B1) side-to-side PCS and (B2) end-to-side PCS. HAF, PVF, and PVP were measured in each animal before and after the surgical procedure. EH increased the PVF/100 g (173%, p < 0.001) and PVP (68%, p < 0.001) but reduced the HAF/100 g (22%, p = 0.819). Following EH, side-to-side PCS reduced the increased PVF (78%, p < 0.001) and PVP (38%, p = 0.001). Without EH, side-to-side PCS reduced the PVF/100 g (68%, p < 0.001) and PVP (12%, p = 0.237). PVP was reduced by end-to-side PCS following EH by 48% (p < 0.001) and without EH by 21% (p = 0.075). PCS can decrease and correct the elevated PVP and PVF/100 g after EH to close to the normal values prior to resection. The decreased HAF/100 g in the remnant liver following EH is increased and corrected through PCS.

Simulating Transplant Small-for-size Grafts Using Human Liver Monosegments: The Impact of Portal Perfusion Pressure

Small-for-size-liver grafts (SFSG) in adult transplant recipients have elevated risk of graft failure, limiting its application in clinical liver transplantation. Relevant preclinical model of SFSG is lacking. Relevant to deceased-donor split liver transplant and living-donor liver transplant in adult recipients, in this study, we present our initial characterization of SFSG model using monosegments of a discarded human donor liver.

Challenges to liver transplantation and strategies to improve outcomes

Liver transplantation (LT) is a highly successful treatment for many patients with nonmalignant and malignant liver diseases. However, there is a worldwide shortage of available organs; many patients deteriorate or die while on waiting lists. We review the important clinical challenges to LT and the best use of the scarce organs. We focus on changes in indications for LT and discuss scoring systems to best match donors with recipients and optimize outcomes, particularly for the sickest patients. We also cover controversial guidelines for the use of LT in patients with hepatocellular carcinoma and cholangiocarcinoma. Strategies to increase the number of functional donor organs involve techniques to perfuse the organs before implantation. Partial LT (living donor and split liver transplantation) techniques might help to overcome organ shortages, and we discuss small-for-size syndrome. Many new developments could increase the success of this procedure, which is already one of the major achievements in medicine during the second part of the 20th century.

Liver resection and metabolic disorders: An undescribed mechanism leading to postoperative mortality

AIM: To investigate the mechanism leading to perioperative mortality in patients undergoing major liver resection and presenting with metabolic disorders.

METHODS: The link between Metabolic Syndrome and non-alcoholic fatty liver disease is currently demonstrated. Various metabolic disorders and the Metabolic Syndrome (the association of ≥ 3 metabolic disorders) have been recently described as a risk factor of perioperative mortality in major liver resection. Patients who passed away during perioperative course of major liver resection and presenting with the association of ≥ 2 metabolic disorders without any other known cause of liver disorders were reviewed.

RESULTS: From January 2001 to May 2010 in a tertiary centre, ten patients presenting with ≥ 2 metabolic disorders without any other known cause of liver disorders died during perioperative course of major liver resection. The same four-consecutive-steps sequence of events occurred, including jaundice. The analysis of this series suggested a rapidly deteriorating congestive liver resulting in an increased portal hypertension leading to hepatorenal syndrome and lately to multiorgan failure (mimicking septic collapse) as the mechanism leading to exitus. The acute portal hypertension is mainly related to the surgical procedure. The chronic portal hypertension is indeterminate. Patients with ≥ 2 metabolic disorders should be considered as potentially presenting with portal hypertension possibly evolving towards hepatorenal syndrome; thus, they should be considered as having a high perioperative risk and should be carefully evaluated before undergoing major liver resection.

CONCLUSION: As fibrosis was not present or marginal in liver specimens, the real cause of portal hypertension in patients with multiple metabolic disorders should be investigated with further studies.

Portal inflow preservation during portal diversion in small-for-size syndrome

AIM: To investigate the impact of portal inflow on liver remnants in a stable pig model of small-for-size syndrome.

METHODS: Twenty pigs underwent mesocaval shunt (MCS) surgery followed by 85%-90% hepatectomy. The control group had no shunt placement; the S₁ group had portal flow maintained at an average of 2.0 times the baseline values; and the S₂ group had portal flow maintained at an average of 3.2 times the baseline flow. The effect of portal functional competition on the liver remnant was investigated for 48 h postoperatively. Data were presented as mean ± SD. Statistical significance was determined using Student’s t test (SPSS, Chicago, IL, United States). Values of P < 0.05 were considered statistically significant.

RESULTS: At 24 h after hepatectomy, biochemical and histological changes were not significantly different between the S₁ and S₂ groups, but changes in both sets of variables were significantly less than in the control group. At 48 h, biochemical and histological changes were significantly less in the S₂ group than in the S₁ or control group. The regeneration index was significantly higher in the S₂ group than in the S₁ group, and was similar to that in the control group. Apoptosis index, serum lipopolysaccharide, and bacterial DNA levels were significantly lower in the S₂ group than in the other two groups.

CONCLUSION: Diversion of portal inflow using MCS reduces portal overflow injury. Excessive diversion of portal inflow inhibits liver regeneration following major hepatectomy. Maintaining portal inflow at an average of 3.2 times above baseline helps promote hypertrophy of the liver remnant and reduce apoptosis.

Hypothermia predicts hepatic failure after extensive hepatectomy in mice

AIM

To investigate the effect of hypothermia on the function of the liver remnant (LR) after extended hepatectomy.

METHODS

We performed a 75% partial hepatectomy (PH) in male C57BL/6J mice. Body temperature was measured with a rectal probe. The study mice were prospectively grouped as hypothermic (HT) or normothermic (NT) if their body temperature was < 34 °C vs ≥ 34 °C, respectively. Blood and liver samples were obtained at 24 and 48 h after 75% PH. Various factors during and after 75% PH were compared at each time point and the most important factor for a good outcome after 75% PH was determined.

RESULTS

At 24 and 48 h after 75% PH, LR weight was decreased in HT mice compared with that in NT mice and the assay results in the HT mice were consistent with liver failure. NT mice had normal liver regeneration. Each intra- and post-operative factor which showed statistical significance in univariate analysis was evaluated by multivariate analysis. The most important factor for a good outcome after 75% PH was body temperature at both 24 and 48 h after surgery.

CONCLUSION

Hypothermia after an extensive hepatectomy predicts impending liver failure and may be a useful clinical marker for early detection of liver failure after extended hepatectomy.

Matrix metalloproteinase-9 contributes to parenchymal hemorrhage and necrosis in the remnant liver after extended hepatectomy in mice

AIM: To investigate the effect of matrix metalloproteinase-9 (MMP-9) on the remnant liver after massive hepatectomy in the mouse.

METHODS: Age-matched, C57BL/6 wild-type (WT), MMP-9(-/-), and tissue inhibitors of metalloproteinases (TIMP)-1(-/-) mice were used. The mice received 80%-partial hepatectomy (PH). Samples were obtained at 6 h after 80%-PH, and we used histology, immunohistochemical staining, western blotting analysis and zymography to investigate the effect of PH on MMP-9. The role of MMP-9 after PH was investigated using a monoclonal antibody and MMP inhibitor.

RESULTS: We examined the remnant liver 6 h after 80%-PH and found that MMP-9 deficiency attenuated the formation of hemorrhage and necrosis. There were significantly fewer and smaller hemorrhagic and necrotic lesions in MMP-9(-/-) remnant livers compared with WT and TIMP-1(-/-) livers (P < 0.01), with no difference between WT and TIMP-1(-/-) mice. Serum alanine aminotransaminase levels were significantly lower in MMP-9(-/-) mice compared with those in TIMP-1(-/-) mice (WT: 476 ± 83 IU/L, MMP-9(-/-): 392 ± 30 IU/L, TIMP-1(-/-): 673 ± 73 IU/L, P < 0.01). Western blotting and gelatin zymography demonstrated a lack of MMP-9 expression and activity in MMP-9(-/-) mice, which was in contrast to WT and TIMP-1(-/-) mice. No change in MMP-2 expression was observed in any of the study groups. Similar to MMP-9(-/-) mice, when WT mice were treated with MMP-9 monoclonal antibody or the synthetic inhibitor GM6001, hemorrhagic and necrotic lesions were significantly smaller and fewer than in control mice (P < 0.05). These results suggest that MMP-9 plays an important role in the development of parenchymal hemorrhage and necrosis in the small remnant liver.

CONCLUSION: Successful MMP-9 inhibition attenuates the formation of hemorrhage and necrosis and might be a potential therapy to ameliorate liver injury after massive hepatectomy.

Effect of a prostaglandin I(2) analog on the expression of thrombomodulin in liver and spleen endothelial cells after an extensive hepatectomy

PURPOSE

Dysfunction of the remnant liver after a hepatectomy is caused by microthrombus formation due to endothelial cell (EC) damage. This study evaluated the effect of prostaglandin I(2) (PGI(2)) on the expression of thrombomodulin (TM), a marker for the anticoagulant properties of ECs, using cultured human umbilical vein endothelial cells (HUVECs), and using a canine extensive hepatectomy model.

METHODS

The presence of PGI(2) receptors was confirmed on HUVECs by reverse transcription-polymerase chain reaction, and the effect of the PGI(2) analog on TM expression on HUVECs was determined by an enzyme-linked immunosorbent assay. Twenty mongrel dogs were divided into four groups comprising a sham operation, 70% hepatectomy, 84% hepatectomy, and 84% hepatectomy, with the administration of the PGI(2) analog, respectively, and TM expression in the liver, spleen, pancreas, kidney, lung, portal vein, and intestine was determined immunohistochemically.

RESULTS

The TM expression on HUVECs was upregulated by the PGI(2) analog. The TM expression on ECs in the hepatic sinusoids and splenic sinus were markedly decreased after the 84% hepatectomy, but such damage was markedly mitigated following an 84% hepatectomy with administration of the PGI(2) analog.

CONCLUSIONS

An extensive hepatectomy induced severe EC damage not only in the hepatic sinusoids but in the splenic sinuses as well. Prostaglandin I(2) prevented damage to these ECs, suggesting that PGI(2) improves the microcirculation in the remnant liver.

Influence of portosystemic shunt on liver regeneration after hepatic resection in pigs

Objective. The minimal amount of liver mass necessary for regeneration is still a matter of debate. The aim of the study was to analyze liver regeneration factors after extended resection with or without portosystemic shunt. Methods. An extended left hemihepatectomy was performed in 25 domestic pigs, in 15 cases after a portosystemic H-shunt. The expression of Ki-67, VEGF, TGF-α, FGF, and CK-7 was analyzed in paraffin-embedded tissue sections. Results. The volume of the remnant liver increased about 2.5-fold at the end of the first week after resection. With 19 cells/10 Glisson fields versus 4/10, Ki-67-expression was significantly higher in the H-shunt group. VEGF- and CK-7-expressions were significantly higher in the control group. No significant change was found in FGF-expression. The expression of TGF-α was higher, but not significantly, in the control group. Conclusions. The expression of Ki-67, and therefore hepatocyte regeneration, was increased in the shunt group. The expression of CK-7 on biliary epithelium and the expression of VEGF, however, were stronger in the control group.

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine

BACKGROUND

When residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.

METHODS

Fourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.

RESULTS

In the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 +/- 3.8 mmHg in the group without a shunt and 10.5 +/- 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.

CONCLUSIONS

These results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine

BACKGROUND

When residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.

METHODS

Fourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.

RESULTS

In the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 +/- 3.8 mmHg in the group without a shunt and 10.5 +/- 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.

CONCLUSIONS

These results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine

BACKGROUND

When residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.

METHODS

Fourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.

RESULTS

In the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 +/- 3.8 mmHg in the group without a shunt and 10.5 +/- 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.

CONCLUSIONS

These results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Hyperperfusion syndrome in small-for-size livers

BACKGROUND

Portal hyperperfusion in small-for-size livers might seriously impair postoperative liver regeneration. Using an experimental model, we investigated splenectomy as a measure to reduce portal blood flow and its impact on postoperative recovery following extended liver resection.

METHOD

Wistar rats underwent partial (90%) hepatectomy with or without splenectomy under temporary inflow occlusion (30 min). In addition to 10-day survival rate, laser Doppler flowmetry of hepatic blood flow and fluorescence microscopic analysis of hepatic microcirculation were performed to assess the effect of splenectomy on initial microvascular reperfusion of liver remnants.

RESULTS

While postischemic perfusion failure was comparable between both groups, portal blood flow was significantly reduced after simultaneous splenectomy (3.5+/-0.4 vs. 5.4+/-0.4 ml/min). Moreover, red blood cell velocity and volumetric blood flow were reduced in splenectomized animals. These animals experienced lower AST levels (421+/-36 vs. 574+/-73 U/l) and a significantly increased survival rate, reaching 6.6+/-1.3 vs 2.6+/-0.8 days.

CONCLUSION

Simultaneous splenectomy significantly reduced the risk for postoperative hyperperfusion syndrome in small-for-size livers. Shear-stress-induced liver injury was diminished due to a significant reduction of portal venous blood flow, which positively influenced postoperative regeneration resulting in significantly higher survival.

Small-for-size syndrome after partial liver transplantation: definition, mechanisms of disease and clinical implications

Widespread application of cadaveric split or living donor liver transplantation bears considerable potential to increase the pool of available organs and thus alleviate the problem of organ shortage. Although splitting of a cadaveric liver into two grafts for adult recipients can be performed successfully, sufficient function of undersized grafts is a major concern. To minimize the risk for living donors, transplant surgeons aim at procuring the least necessary liver volume, also leading to potentially small grafts. When small partial grafts are unable to meet the functional demands, the recipients can develop a so-called small-for-size syndrome (SFSS). There is currently limited data on the pathogenesis of SFSS, with clinical studies mainly focusing on portal hyperperfusion. Additional aspects include graft-related factors such as functional and regenerative capacity, as well as recipient-related factors, such as overall health status and severity of cirrhosis. However, there is currently no consensus on the definition of SFSS. We propose a novel definition, based on simple clinical criteria, which divides the syndrome into either nonfunction or dysfunction of a small graft after the exclusion of other causes. This definition should ease comparability of future clinical trials, and thus improve understanding of the pathogenesis of SFSS.

Jejunectomy can reduce excessively elevated portal pressure after major hepatectomy in beagle dogs

A number of factors can lead to the life-threatening liver dysfunction in the aftermath of an extended hepatectomy. Prominent among them is the high portal pressure induced by the concentrated flow of the entire stream of portal blood toward the small remnant liver. Twelve beagle dogs were randomly divided into group A (n=6, 70% hepatectomy) and group B (n=6, 70% hepatectomy after jejunectomy). Three dogs in each group were euthanized at 1 or 4 weeks after the operation and examined to evaluate hemodynamic changes, liver functions, and liver histology. One hour after the hepatectomy, the animals in group B exhibited a significantly lower portal pressure (P=0.002) and significantly higher hepatic arterial flow (P=0.004) than the animals in group A. As more time passed, the total hepatic flow and hepatic tissue flow both rose up to levels significantly higher than those in group A (P=0.037 and P=0.025, respectively). The alkaline phosphatase, total protein, albumin, and anti-thrombin III were all significantly better in group B than in group A on the 1st post-operative day. Liver specimens biopsied at 1 h after the hepatectomy showed significantly more swelling of the hepatocytes in group A than in group B. In addition, an immunohistochemical study using the TUNEL method for liver biopsy on the seventh post-operative day revealed numerous positive cells in group A but few in group B. Our results suggest that the portal pressure control by the enterectomy can forestall dysfunction of the remnant liver after extended hepatectomy, especially during the early post-operative period.

The interrelationship between portal and arterial blood flow after adult to adult living donor liver transplantation

BACKGROUND

When adults are transplanted with segmental grafts, disparity between the size of the graft and the native organ is almost universal. These grafts presumably still receive all of the native portal inflow despite a reduced vascular bed and dramatically elevated blood flow may result. The hemodynamic changes after segmental transplantation in adults have not yet been studied and their clinical significance is unknown.

METHODS

Portal venous and hepatic arterial blood flow were measured intraoperatively in right lobe liver donors and recipients with electromagnetic flow probes. Postoperative evolution was monitored in recipients with ultrasonography.

RESULTS

Portal flow to the right lobe ranged from 601 to 1,102 ml/min before resection and from 1,257 to 2,362 ml/min after transplantation. There was a statistically significant linear correlation between the change in portal flow and graft to recipient body weight ratio. Arterial blood flow ranged from 213 to 460 ml/min before resection and from 60 to 300 ml/min after transplantation. Preoperative portal peak systolic velocity was uniformly around 10 cm/sec. Values on postoperative day 1 were increased to 30 cm/sec in recipients of cadaveric organs, to 50 cm/sec in recipients of organs with graft to recipient body weight ratios of more than 1.2%, and to 115 cm/sec in recipients of organs with ratios less than 0.9%. A decreasing tendency was universally observed. Arterial systolic velocity was inversely related to portal systolic velocity. Neither graft dysfunction nor vascular complications occurred.

CONCLUSIONS

The hemodynamic pattern after right lobe transplantation is predictable and intraoperative measurements and ultrasonography are useful for monitoring. The size of the graft influences the magnitude of the hemodynamic changes.

Emergency portacaval shunt for control of hemorrhage from a parenchymal fracture after adult-to-adult living donor liver transplantation

As more adults undergo transplantation with partial liver grafts, the unique features of these segments and their clinical significance will become apparent. A patient presented with life-threatening hemorrhage from an iatrogenic laceration to a right lobe graft 11 days after transplantation. The creation of a portacaval shunt effectively controlled the bleeding, allowing more elective replacement of the organ with another right lobe graft. The regeneration process combined with increased portal blood flow and relative outflow limitation may have set the stage for this complication. Any disruption of the liver parenchyma during transplantation should be securely repaired and followed cautiously. Portacaval shunting is an option for controlling hemorrhage from the liver in transplant recipients. The timely availability of a second organ was likely the ultimate determinant of survival for this patient.

Right lobe living donor liver transplantation: a review

The continuing shortage of organs for adult transplant recipients has generated enthusiasm for adult-to-adult living donor liver transplantation (LDLT). The major concern has been the ability to resect a graft of adequate size without subjecting the donor to undue risk. The right hepatic lobe is generally large enough for adult recipients, but because of the real and perceived risks of right lobe (RL) resection, surgeons have been hesitant to offer this option to their patients. The first series of RL resections that included a significant number of patients was reported in 1999, and the results were encouraging. Only minor complications occurred in donors, and the recipients fared quite well. Enthusiasm for these donor resections is growing, and more centers are beginning to perform them. There is a good deal of global experience with pediatric LDLT but little with adults, and there are unique considerations in this population. This review examines donor selection criteria for adult recipients, highlights technical points critical for good outcome, and examines the early results and complications in both donors and recipients. If the preliminary results continue to be reproduced, RL LDLT could have significant impact on the worsening organ shortage.

Treatment for accidental occlusion of the hepatic artery after hepatic resection: report of two cases

Two patients in whom accidental hepatic artery occlusion (HAO) occurred after hepatic resection (Hx) were reported. A 59-year-old female who underwent Hx for hepatocellular carcinoma with underlying liver cirrhosis developed HAO on postoperative day (POD) 14 and died of hepatic failure on POD 23. The autopsy findings showed multiple necrosis in the remnant liver and an extraluminal hematoma of the hepatic artery, suggesting an injury caused by Pringle's maneuver. The second case was a 53-year-old male who underwent Hx for cholangiocarcinoma without any underlying liver disease. He developed HAO on POD 6, and radiological studies indicated a pseudoaneurysma formation and severe stenosis of the hepatic artery. It was speculated that the cause of the HAO was intraluminal injury of the hepatic artery during an angiographic study conducted prior to Hx. Partial arterialization of the portal vein was performed, following which his liver function test results improved. In both cases, measuring the serum hepatocyte growth factor level and the hepatic vein oxygen saturation proved useful, not only for determining the degree of liver injury, but also for predicting the outcome after treatments for HAO. Furthermore, the partial arterialization of the portal vein for HAO after Hx may rescue the normal remnant liver.