Hypothermic Liver Perfusion Research Articles

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.

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. 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). 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. 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.

Highly complex liver resections: Exploring the boundaries of feasibility and safety.

In select clinical scenarios, advanced techniques for volume manipulation and vascular reconstruction are needed for complete hepatic tumor removal. These highly complex liver resections (HCLRs) entail a heightened risk of severe complications. Here, we describe the results of HCLR performed in a 3-year time period. We conducted a retrospective analysis encompassing patients who underwent hepatic resections between June 15, 2020, and June 15, 2023. HCLR was defined according to previously established criteria, and included associating liver partition and portal vein ligation for staged hepatectomy.The outcomes of HCLR were compared to all non-HCLR performed within the same time frame. Among 167 hepatic resections, 26 were considered HCLR, and all were major resections. Five utilized total vascular exclusion, with venovenous bypassin three, and hypothermic liver perfusion in three. Five resections included vascular reconstructions, and one included hypothermic circulatory arrest for extraction of a tumor extending to the right atrium. Of the non-HCLR, 38 (26.9%) were major, and 49 (34.7%) were performed laparoscopically. The rates of overall major postoperative complications were comparable between those who underwent HCLR versus non-HCLR. HCLR was associated with increased rates of biliary complications, readmissions, and reoperation. However, no postoperative 90-day mortality was documented within patients that underwent HCLR compared to two in the non-HCLR group. In expert hands, HCLR can be performed with acceptable complication profile, akin to that of major non-HCLR. Those with questionable resectability should be referred to tertiary hepato-pancreato-biliary centers.

313.16: Glycocalyx Damage Marker Syndecan-1 Correlates With Early Allograft Dysfunction During Hypothermic Liver Machine Perfusion

Introduction: The endothelial glycocalyx is mainly consisting of Syndecan-1 (Sdc-1) which is released into human serum upon glycocalyx degradation. Glycocalyx alterations are connected to different aspects of organ damage and have been recently investigated in the context of liver transplantation. Due to shortage of donor organs, new preservation methods as hypothermic oxygenated machine perfusion (HOPE) have been introduced to enable transplantation of organs with a higher risk profile. For safe expansion of the donor pool, reliable organ assessment markers for evaluation during machine perfusion are missing. We aimed to measure glycocalyx damage during hypothermic liver perfusion. Methods: HOPE was performed with the Organ Assist® perfusion system on 40 livers, prior to organ transplantation. Samples were collected during (perfusate at 0 and 60 min) and after HOPE (effluent). Sdc-1 concentration in samples was measured by ELISA as indicator for glycocalyx destruction. We compared clinical parameters with Sdc-1 levels in patients regarding the development of early allograft dysfunction (EAD) using Mann-Whitney U test, Pearson correlation and receiver operating characteristics (ROC). Results: The 13 patients which developed EAD, showed an elevation in Sdc-1 concentration compared to non-EAD patients during HOPE at 0 min: [598 (±526) vs. 276 (±150) ng/ml; p=0.076] and 60 min: [1099 (±739) vs. 521 (±382) ng/ml; p=0.016], as well as afterwards in the effluent: [2074 (±1273) vs. 443 (±226) ng/ml; p=0.001 (n=15, 4 with EAD)]. Concentration of Sdc-1 during HOPE correlated with EAD at 0 min: (R=0.433, p=0.006), at 60 min: (R=0.471, p=0.003) and in the effluent: (R=0.769, p<0.001, n=15, 4 with EAD). Furthermore, an association between EAD and Sdc-1 concentrations was indicated by ROCs: during HOPE at 60 minutes: (AUC=0.704 and p=0.018) and in the effluent: (AUC=1 and p=0.004 (n=15, 4 with EAD)). No association of graft survival with Sdc-1 (p=0.339) was detected in cox regression analysis however, reduced graft survival (log-rank=0.009) of EAD patients compared to those without EAD could be shown. Conclusion: We found that measuring glycocalyx degradation during HOPE could indicate transplantation outcome regarding EAD. Consequently, we argue that Sdc-1 could be a useful biomarker for organ assessment during HOPE.

Left renal vein graft and in situ hepatic perfusion in hepatectomy for complete tumor invasion of hepatic veins: hemodynamic optimization and surgical technique

PurposeAssessing hepatic vein reconstruction using a left renal vein graft and in situ hypothermic liver perfusion in an extended liver resection.MethodsPatients included in this study were those with liver tumors undergoing curative surgery with resection and reconstruction of hepatic veins. Hepatic vein was reconstructed using a left renal vein graft. We describe the technical aspects of liver resection and vascular reconstruction, the key aspects of hemodynamic management, and the use of in situ hypothermic liver preservations during liver transection (prior to and during vascular clamping).ResultsThe right hepatic vein was reconstructed with a median left renal venal graft length of 4.5 cm (IQR, 3.1–5.2). Creatinine levels remained within normal limits in the immediate postoperative phase and during follow-up. Median blood loss was 500 ml (IQR, 300–1500) and in situ perfusion with cold ischemia was 67 min (IQR, 60.5–77.5). The grafts remained patent during the follow-up with no signs of thrombosis. No major postoperative complications were observed.ConclusionLeft renal vein graft for the reconstruction of a hepatic vein and in situ hypothermic liver perfusion are feasible during extended liver resection.

Flavin Mononucleotide as a Biomarker of Organ Quality-A Pilot Study.

Background.Flavin mononucleotide (FMN), released from damaged mitochondrial complex I during hypothermic liver perfusion, has been shown to be predictive of 90-day graft loss. Normothermic machine perfusion (NMP) and normothermic regional perfusion (NRP) are used for organ reconditioning and quality assessment before transplantation. This pilot study aimed to investigate the changes of FMN levels during normothermic reperfusion of kidneys, livers, and lungs and examine whether FMN could serve as a biomarker to predict posttransplant allograft quality.Methods.FMN concentrations, in perfusates collected during NMP of kidneys, abdominal NRP, and ex vivo lung perfusion, were measured using fluorescence spectrometry and correlated to the available perfusion parameters and clinical outcomes.Results.Among 7 transplanted kidneys out of the 11 kidneys that underwent NMP, FMN levels at 60 minutes of NMP were significantly higher in the allografts that developed delayed graft function and primary nonfunction (P = 0.02). Fifteen livers from 23 circulatory death donors that underwent NRP were deemed suitable for transplantation. Their FMN levels at 30 minutes of NRP were significantly lower than those not procured for transplantation (P = 0.004). In contrast, little FMN was released during the 8 lung perfusions.Conclusions.This proof of concept study suggested that FMN in the perfusates of kidney NMP has the potential to predict posttransplant renal function, whereas FMN at 30 minutes of NRP predicts whether a liver would be accepted for transplantation. More work is required to validate the role of FMN as a putative biomarker to facilitate safe and reliable decision-making before embarking on transplantation.

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

BackgroundWhile 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. MethodsAll 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−). ResultsTwenty-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). ConclusionDuring 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.

Hypothermic Perfusion Hepatectomy for Unresectable Liver Cancer: A Single-Center Experience

Introduction: Despite technical advancements in liver surgery, resection of liver tumors that involve the hepatic veins adjacent to the vena cava or hepatic hilum remains technically challenging. We present our surgical techniques and the long-term outcome of 5 patients with conventionally unresectable tumors. Method: Between September 1999 and March 2016, we encountered 5 patients with conventionally unresectable tumors that were successfully treated by “ex-situ liver resection” and “in-situ & ante -situm hypothermic liver perfusion” under total vascular exclusion and venovenous bypass. Result: These approaches allowed complete tumor removal with vascular reconstruction under a bloodless operation field, while minimizing hepatic ischemic injury and preserving liver function. No perioperative mortalities occurred and postoperative complications were minimal. The postoperative survival periods were limited due to the advanced malignancies in our patients, but the survival benefit was encouraging. The median postoperative survival time was 29.1 months, with the longest survival period being nearly 10 years. Furthermore, these approaches improved the quality of life and provided our patients with an opportunity for additional treatment. Conclusion: Hypothermic perfusion hepatectomy is a realistic option for achieving surgical cure or significantly improved survival and quality of life in patients with tumors deemed unresectable using conventional normothermic hepatectomy. These approaches can overcome the limitations of the liver’s restricted normothermic ischemia tolerance or inaccessible tumor locations.

Hypothermic liver perfusion.

The review describes recent developments in hypothermic machine liver perfusion with a special focus on underlying protective mechanisms, and the role of this perfusion technique in high-risk donor-recipient combinations. To maximize the number of transplantable donor livers, several centres are exploring new machine preservation techniques. In this context, hypothermic machine perfusion has been recently introduced into the clinical setting of human liver transplantation, and the effect of endischemic cold liver perfusion on posttransplant complications is currently under investigation in two multicentre, randomized controlled trials. In addition, current case series demonstrated promising results regarding the protection from intrahepatic biliary complications, particularly when livers from extended criteria donors including donation after circulatory death grafts were used. Hypothermic machine perfusion may, therefore, help to push the boundaries of acceptance criteria for high-risk donor livers. In this review, we, first, describe the concept of hypothermic machine liver perfusion and present results from current clinical studies. Next, we provide details of our perfusion approach step-by-step and highlight novel pathways of reperfusion injury and protection. Third, we discuss the impact of this perfusion approach in different clinical scenarios. Finally, we report on recent clinical implementations and future aspects.

Hypothermic liver perfusion.

Hypothermic liver perfusion.

Hydroxyethyl starch-based preservation solutions enhance gene therapy vector delivery under hypothermic conditions

Isolated liver perfusion offers a unique prospect for safe, effective targeting of gene therapies that can be directed against allograft rejection or recurrent diseases such as reinfection by hepatitis C virus (HCV). We aimed to examine the effect of organ preservation solutions on vector-based gene therapy delivery under hypothermic conditions. University of Wisconsin (UW) solution, histidine tryptophan ketoglutarate (HTK), EloHaes, sodium-poly(ethylene glycol)-UW solution [Institut Georges Lopez 1 solution (IGL-1)], and Dulbecco's modified Eagle's medium (DMEM) culture medium (control) were tested at 2 degrees C or 37 degrees C for lentiviral vector transduction efficiencies to the hepatoma cell line Huh-7 and primary human or mouse hepatocytes. Lentiviral vectors expressing short hairpin RNA were used to target HCV replication. With a potent short hairpin RNA vector, transductions were directly correlated to the therapeutic effect, with low transduction yielding low knockdown and vice versa. Green fluorescent protein (GFP) reporter gene expression was observed with vector incubation times as short as 10 minutes. The highest transductions were seen, after 2-hour 37 degrees C incubation, in UW (62% +/- 6 SEM); they were significantly higher than those in HTK (21% +/- 7 SEM). Neither adenosine nor glutathione, present in UW, provided any increase in transduction when supplemented to HTK, although the addition of hydroxyethyl starch (HES) significantly improved transductions. To rule out size exclusion as a mechanism of HES, IGL-1 was tested but did not result in better transductions than HTK or DMEM. When supplemented to UW, anionic compounds reduced transduction, and this indicated a charge interaction mechanism of HES. In conclusion, this study demonstrates that effective vector delivery can be achieved under conditions of hypothermic liver perfusion. UW provides superior transduction to hepatocytes over nonstarch solutions.

Numerical simulation of the hepatic circulation.

Availability of donor livers and the relatively short preservation time limit the success of liver transplantation. The use of hypothermic machine perfusion could pave the way for expansion of the donor pool. To better define optimal settings of such a device, the feasibility of using a numerical simulation model of the hepatic circulation is determined. Hemodynamics in the hepatic arterial, portal venous and hepatic venous compartments of the hepatic vascular tree was modelled using an electrical analogue. Calculated pressure and flow profiles throughout the liver were in accordance with physiologic profiles in the total circulatory system. Comparison of calculated flow values with normal control values showed a discrepancy that was explained by inaccurate diameter input data. Until more precise methods for determining vascular dimensions become available, redefining vessel diameter makes the simulation model perfectly suitable for predicting influences of temperature and/or viscosity on hepatic hemodynamics and is thereby an excellent tool in defining optimal settings for our hypothermic liver perfusion system.

Decrease in core liver temperature with 10°C by in situ hypothermic perfusion under total hepatic vascular exclusion reduces liver ischemia and reperfusion injury during partial hepatectomy in pigs

Objective We attempted to assess liver ischemia/reperfusion injury under a mild decrease in core liver temperature of 10° C by in situ hypothermic perfusion during ischemia. Methods Liver ischemia was induced in pigs by total hepatic vascular exclusion with concomitant in situ perfusion with hypothermic (4°C) Ringer-glucose (cold perfused group, core liver temperature maintained at 28°C), with normothermic (38°C) Ringer-glucose (warm perfused group) or without in situ perfusion (control group). Results In the cold perfused, warm perfused, and control groups, 24-hour survival was 5/5, 0/5, and 3/5, respectively. Hemodynamic parameters in the cold perfused group remained stable, whereas pigs in both other groups required circulatory support. Plasma AST and interleukin-6 levels were lower in the cold perfused group than in both other groups. Hepatocellular function was best preserved in the cold perfused group as indicated by complete recovery of bile production during reperfusion and no loss of indocyanine green clearance capacity. In both other groups, bile production and indocyanine green clearance capacity were reduced significantly. The hyaluronic acid uptake capacity of pigs in the cold perfused group or control group did not differ, indicating preserved sinusoidal endothelial cell function. Histopathologic injury scores during reperfusion were significantly lower in the cold perfused group when compared to both other groups. Conclusions A mild decrease in core liver temperature of 10°C by in situ hypothermic liver perfusion during ischemia protects the liver from ischemia/reperfusion injury. This protection appears to be related to cooling of the liver rather than to the washout of blood during perfusion.

Ex-vivo resection techniques in tissue-preserving surgery for liver malignancies

Some primary and secondary liver tumours are not absolutely irresectable, but cannot be resected using a conventional approach because of the limited warm ischaemia tolerance of the liver or poor accessibility of the tumour region. In such situations, the techniques of ex vivo liver surgery, pioneered by Rudolf Pichlmayr some 10 years ago, offer new chances for R0 resection. All the three different approaches, namely "in situ"-, "ante situm"-, and "ex situ" resection, require the use of measures originally developed for transplantation, such as hypothermic liver perfusion and veno-venous bypass. They differ mainly in the extent to which major vessels are divided in order to achieve optimal mobility of the organ. The results show that radical resection can be achieved accomplished in many cases. If necessary, complex vascular reconstructions can be performed. Although perioperative morbidity and mortality are high, there are a number of long-term survivors. Tumour recurrence, however, remains the main problem over the long term. In conclusion, ex vivo liver surgery is an important extension of surgical treatment possibilities. However, the procedure is suitable only for a small number of carefully selected patients and should be reserved for use in specialised centres. Furthermore, in view of the fact that the results are not yet optimal, additive and adjuvant treatment modalities are needed.

The effects of increasing the oncotic and osmotic pressure of the perfusate on bloodless hypothermic perfusion of liver in the rat

The effects of increasing the oncotic and osmotic pressure of the perfusate on bloodless hypothermic perfusion of liver in the rat

Experimental studies on continuous hypothermic liver perfusion with a synthetic solution containing gelatin polypeptides (Haemaccel)

A rat liver model has been developed for studying preservation by continuous hypothermic perfusion. Perfusion for 5 and 24 hr with a defined solution containing Haemaccel as colloid at a temperature of 5–7 °C was found to result in good preservation of the metabolic activity of the livers as assessed by the ability of the tissue to synthesize urea and take up galactose. In common with other continuous perfusion methods, there was increasing evidence of cell damage as perfusion progressed, and there was an associated depletion of cellular K + and an increase in tissue water content. There was a considerable increase in vascular resistance, as indicated by a fall in flow rate at a constant pressure in the later stages of perfusion, similar to that which has been reported in other liver preservation experiments using plasma derivatives or Dextran. Further studies are envisaged to attempt to analyze, in a controlled fashion, the nature of the damage incurred by the liver during storage and the requirements for maintenance of a viable graft at hypothermia.

A System for Automatic Control of Perfusate pH during Hyperbaric and Normobaric Hypothermic Perfusion of Liver

A system is described for automatic adjustment of pH in an isolated organ preservation circuit. The system incorporates a pH monitor and gasometric titrating device which has been shown to be superior to manual pH control under hyperbaric and ambient pressure conditions for periods of 12 h.

Asanguinous hypothermic liver perfusion in dogs

An original, simplified, and consistently reproducible technique for isolation and perfusion of the canine liver in vivo was developed after experimentation upon over 60 dogs. The hepatic outflow was isolated by use of an intracaval shunt and creation of a chamber containing pure hepatic effluent surrounding the shunt. This is accomplished through an abdominal approach. The need for heparinization and extracorporeal circulation has been eliminated. The procedure is free from systemic admixture as assessed by BSP determination. Regional hepatic hypothermia is maintained at 14°C. to 16°C. without systemic hypothermia. Contamination with blood is reduced to less than 1 cc. per minute (hematocrit of the effluent is consistently less than 1%) after the washout. Hepatic outflow block was not observed either during or after perfusion. Hypotension did not follow revascularization in perfusions lasting up to 90 minutes. Mild hypotension followed perfusions up to 180 minutes but was spontaneously reversed without the need for vasopressors. Eleven of 15 dogs survived after being perfused between 60 and 90 minutes. Three of 6 dogs survived after being perfused 120 minutes. Death could be attributed to hepatic failure in the dogs perfused for longer periods of time.