Introduction of the Concept of Diagnostic Sensitivity and Specificity of Normothermic Perfusion Protocols to Assess High-Risk Donor Livers.

Normothermic machine perfusion (NMP) allows objective assessment of donor liver transplantability. Several viability evaluation protocols have been established, consisting of parameters such as perfusate lactate clearance, pH, transaminase levels, and the production and composition of bile. The aims of this study were to assess 3 such protocols, namely, those introduced by the teams from Birmingham (BP), Cambridge (CP), and Groningen (GP), using a cohort of high-risk marginal livers that had initially been deemed unsuitable for transplantation and to introduce the concept of the viability assessment sensitivity and specificity. To demonstrate and quantify the diagnostic accuracy of these protocols, we used a composite outcome of organ use and 24-month graft survival as a surrogate endpoint. The effects of assessment modifications, including the removal of the most stringent components of the protocols, were also assessed. Of the 31 organs, 22 were transplanted after a period of NMP, of which 18 achieved the outcome of 24-month graft survival. The BP yielded 94% sensitivity and 50% specificity when predicting this outcome. The GP and CP both seemed overly conservative, with 1 and 0 organs, respectively, meeting these protocols. Modification of the GP and CP to exclude their most stringent components increased this to 11 and 8 organs, respectively, and resulted in moderate sensitivity (56% and 44%) but high specificity (92% and 100%, respectively) with respect to the composite outcome. This study shows that the normothermic assessment protocols can be useful in identifying potentially viable organs but that the balance of risk of underuse and overuse varies by protocol.

Short-term outcomes after pancreatoduodenectomy in octogenarians: multicentre case-control study.

BACKGROUND: Pancreatoduodenectomy (PD) is frequently the surgical treatment indicated for a number of pathologies. Elderly patients may be denied surgery because of concerns over poor perioperative outcomes. The aim of this study was to evaluate postoperative clinical outcomes and provide evidence on current UK practice in the elderly population after PD. METHODS: This was a multicentre retrospective case-control study of octogenarians undergoing PD between January 2008 and December 2017, matched with younger controls from seven specialist centres in the UK. The primary endpoint was 90-day mortality. Secondary endpoints were index admission mortality, postoperative complications, and 30-day readmission rates. RESULTS: In total, 235 octogenarians (median age 81 (range 80-90) years) and 235 controls (age 67 (31-79) years) were included in the study. Eastern Cooperative Oncology Group performance status (median 0 (range 0-3) versus 0 (0-2); P = 0.010) and Charlson Co-morbidity Index score (7 (6-11) versus 5 (2-9); P = 0.001) were higher for octogenarians than controls. Postoperative complication and 30-day readmission rates were comparable. The 90-day mortality rate was higher among octogenarians (9 versus 3 per cent; P = 0.030). Index admission mortality rates were comparable (4 versus 2 per cent; P = 0.160), indicating that the difference in mortality was related to deaths after hospital discharge. Despite the higher 90-day mortality rate in the octogenarian population, multivariable Cox regression analysis did not identify age as an independent predictor of postoperative mortality. CONCLUSION: Despite careful patient selection and comparable index admission mortality, 90-day and, particularly, out-of-hospital mortality rates were higher in octogenarians.

Rates of Bile Acid Diarrhoea After Cholecystectomy: A Multicentre Audit.

INTRODUCTION: Bile acid diarrhoea (BAD) can occur due to disruption to the enterohepatic circulation, e.g. following cholecystectomy. Post-cholecystectomy diarrhoea has been reported in 2.1-57.2% of patients; however, this is not necessarily due to BAD. The aim of this study was to determine the rates of bile acid diarrhoea diagnosis after cholecystectomy and to consider investigation practices. METHODS: A retrospective analysis of electronic databases from five large centres detailing patients who underwent laparoscopic cholecystectomy between 2013 and 2017 was cross-referenced with a list of patients who underwent 75SeHCAT testing. A 7-day retention time of <15% was deemed to be positive. Patient demographics and time from surgery to investigation were collected and compared for significance (p < 0.05). RESULTS: A total of 9439 patients underwent a laparoscopic cholecystectomy between 1 January 2013 and 31 December 2017 in the five centres. In total, 202 patients (2.1%) underwent investigation for diarrhoea via 75SeHCAT, of which 64 patients (31.6%) had a 75SeHCAT test result of >15%, while 62.8% of those investigated were diagnosed with bile acid diarrhoea (BAD). In total, 133 (65.8%) patients also underwent endoscopy and 74 (36.6%) patients had a CT scan. Median time from surgery to 75SeHCAT test was 672 days (SD ± 482 days). DISCUSSION/CONCLUSION: Only a small proportion of patients, post-cholecystectomy, were investigated for diarrhoea with significant time delay to diagnosis. The true prevalence of BAD after cholecystectomy may be much higher, and clinicians need to have an increased awareness of this condition due to its amenability to treatment. 75SeHCAT is a useful tool for diagnosis of bile acid diarrhoea.

Manipulation of Lipid Metabolism During Normothermic Machine Perfusion: Effect of Defatting Therapies on Donor Liver Functional Recovery.

Strategies to increase the use of steatotic donor livers are required to tackle the mortality on the transplant waiting list. We aimed to test the efficacy of pharmacological enhancement of the lipid metabolism of human livers during ex situ normothermic machine perfusion to promote defatting and improve the functional recovery of the organs. Because of steatosis, 10 livers were discarded and were allocated either to a defatting group that had the perfusate supplemented with a combination of drugs to enhance lipid metabolism or to a control group that received perfusion fluid with vehicle only. Steatosis was assessed using tissue homogenate and histological analyses. Markers for lipid oxidation and solubilization, oxidative injury, inflammation, and biliary function were evaluated by enzyme-linked immunosorbent assay, immunohistochemistry, and in-gel protein detection. Treatment reduced tissue triglycerides by 38% and macrovesicular steatosis by 40% over 6 hours. This effect was driven by increased solubility of the triglycerides (P = 0.04), and mitochondrial oxidation as assessed by increased ketogenesis (P = 0.008) and adenosine triphosphate synthesis (P = 0.01) were associated with increased levels of the enzymes acyl-coenzyme A oxidase 1, carnitine palmitoyltransferase 1A, and acetyl-coenzyme A synthetase. Concomitantly, defatted livers exhibited enhanced metabolic functional parameters such as urea production (P = 0.03), lower vascular resistance, lower release of alanine aminotransferase (P = 0.049), and higher bile production (P = 0.008) with a higher bile pH (P = 0.03). The treatment down-regulated the expression of markers for oxidative injury as well as activation of immune cells (CD14; CD11b) and reduced the release of inflammatory cytokines in the perfusate (tumor necrosis factor α; interleukin 1ß). In conclusion, pharmacological enhancement of intracellular lipid metabolism during normothermic machine perfusion decreased the lipid content of human livers within 6 hours. It also improved the intracellular metabolic support to the organs, leading to successful functional recovery and decreased expression of markers of reperfusion injury.

Ex situ machine perfusion as a tool to recondition steatotic donor livers: Troublesome features of fatty livers and the role of defatting therapies. A systematic review.

Long-standing research has shown that increased lipid content in donor livers is associated with inferior graft outcomes posttransplant. The global epidemic that is obesity has increased the prevalence of steatosis in organ donors, to the extent that it has become one of the main reasons for declining livers for transplantation. Consequently, it is one of the major culprits behind the discrepancy between the number of donor livers offered for transplantation and those that go on to be transplanted. Steatotic livers are characterized by poor microcirculation, depleted energy stores because of an impaired capacity for mitochondrial recovery, and a propensity for an exaggerated inflammatory response following reperfusion injury culminating in poorer graft function postoperatively. Ex situ machine perfusion, currently a novel method in graft preservation, is showing great promise in providing a tool for the recovery and reconditioning of marginal livers. Hence, reconditioning these steatotic livers using machine perfusion has the potential to increase the number of liver transplants performed. In this review, we consider the problematic issues associated with fatty livers in the realm of transplantation and discuss pharmacological and nonpharmacological options that are being developed to enhance recovery of these organs using machine perfusion and defatting strategies.

Combined Hypothermic and Normothermic Machine Perfusion Improves Functional Recovery of Extended Criteria Donor Livers.

Hypothermic oxygenated perfusion (HOPE) and normothermic perfusion are seen as distinct techniques of ex situ machine perfusion of the liver. We aimed to demonstrate the feasibility of combining both techniques and whether it would improve functional parameters of donor livers into transplant standards. Ten discarded human donor livers had either 6 hours of normothermic perfusion (n = 5) or 2 hours of HOPE followed by 4 hours of normothermic perfusion (n = 5). Liver function was assessed according to our viability criteria; markers of tissue injury and hepatic metabolic activity were compared between groups. Donor characteristics were comparable. During the hypothermic perfusion phase, livers down-regulated mitochondrial respiration (oxygen uptake, P = 0.04; partial pressure of carbon dioxide perfusate, P = 0.04) and increased adenosine triphosphate levels 1.8-fold. Following normothermic perfusion, those organs achieved lower tissue expression of markers of oxidative injury (4-hydroxynonenal, P = 0.008; CD14 expression, P = 0.008) and inflammation (CD11b, P = 0.02; vascular cell adhesion molecule 1, P = 0.05) compared with livers that had normothermic perfusion alone. All livers in the combined group achieved viability criteria, whereas 40% (2/5) in the normothermic group failed (P = 0.22). In conclusion, this study suggests that a combined protocol of hypothermic oxygenated and normothermic perfusions might attenuate oxidative stress, tissue inflammation, and improve metabolic recovery of the highest-risk donor livers compared with normothermic perfusion alone.

Oncological outcomes after pancreatoduodenectomy for pancreatic ductal adenocarcinoma in octogenarians: case-control study.

BACKGROUND: By the end of this decade, 70 per cent of all diagnosed pancreatic ductal adenocarcinomas will be in the elderly. Surgical resection is the only curative option. In the elderly perioperative mortality is higher, while controversy still exists as to whether aggressive treatment offers any survival benefit. This study aimed to assess the oncological benefit of pancreatoduodenectomy in octogenarians with pancreatic ductal adenocarcinoma. METHOD: Retrospective multicentre case-control study of octogenarians and younger controls who underwent pancreatoduodenectomy for pancreatic ductal adenocarcinoma between 2008 and 2017. The primary endpoint was overall survival and the secondary endpoint was disease-free survival. RESULTS: Overall, 220 patients were included. Although the Charlson co-morbidity index was higher in octogenerians, Eastern Cooperative Oncology Group performance status, ASA and pathological parameters were comparable. Adjuvant therapy was more frequently delivered in the younger group (n = 80, 73 per cent versus n = 58, 53 per cent, P = 0.006). There was no significant difference between octogenarians and controls in overall survival (20 versus 29 months, P = 0.095) or disease-free survival (19 versus 22 months, P = 0.742). On multivariable analysis, age was not an independent predictor of either oncological outcome measured. CONCLUSION: Octogenarians with pancreatic ductal adenocarcinoma of the head and uncinate process may benefit from comparable oncological outcomes to younger patients with surgical treatment. Due to the age- and disease-related frailty and co-morbidities, careful preoperative assessment and patient selection is of paramount importance.

Postcholecystectomy diarrhoea rate and predictive factors: a systematic review of the literature.

OBJECTIVES: Cholecystectomy is one of the most common surgical procedures performed worldwide to treat gallstone-related disease. Postcholecystectomy diarrhoea (PCD) is a well-reported phenomenon, however, the actual rate, predictive factors and mechanism of action have not been well determined. A systematic review was undertaken to determine the rate and predictive factors associated with diarrhoea in the postcholecystectomy setting. METHODS: The review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocol. Databases searched included Medline, Embase, Pubmed, Cochrane and Google Scholar up to 29 September 2020. The inclusion criteria consisted of cohort studies or randomised trials which investigated the rate of PCD and predictive factors. Case reports, case series, conference abstracts and expert opinion pieces were excluded as were other systematic reviews as all the original articles from those reviews were included in this review. Papers that did not include PCD as a separate entity were excluded. Bias assessment was performed using the Newcastle-Ottawa Scale for cohort studies and the Cochrane risk of bias tool for randomised controlled trials as appropriate. Data were extracted by two authors (AF and JAA) and an overall rate of PCD was calculated. Predictive factors were also extracted and compared between studies. RESULTS: 1204 papers were obtained and 21 were found to contain relevant information about PCD, including the number of patients developing diarrhoea, method of symptom assessment and time of onset postcholecystectomy. A pooled total of 3476 patients were included across the identified studies with 462 (13.3%) patients developing PCD. Possible predictive factors varied across all studies, with characteristics such as gender, age and weight of patients postulated as being predictive of PCD, with no agreement across studies. DISCUSSION: PCD is therefore relatively common (13.3%). This has important implications for patient consent. Patients ought to be investigated early for bile acid diarrhoea in suspected PCD. More studies are required to determine the possible predictive factors for PCD. Limitations of the study included that most studies were not powered for calculation of PCD, and assessment methods between studies varied. PROSPERO REGISTRATION NUMBER: CRD42019140444.

Ex situ Normothermic Split Liver Machine Perfusion: Protocol for Robust Comparative Controls in Liver Function Assessment Suitable for Evaluation of Novel Therapeutic Interventions in the Pre-clinical Setting.

Background: Ex situ donor liver machine perfusion is a promising tool to assess organ viability prior to transplantation and platform to investigate novel therapeutic interventions. However, the wide variability in donor and graft characteristics between individual donor livers limits the comparability of results. We investigated the hypothesis that the development of a split liver ex situ machine perfusion protocol provides the ideal comparative controls in the investigation of machine perfusion techniques and therapeutic interventions, thus leading to more comparable results. Methods: Four discarded human donor livers were surgically split following identification and separation of right and left inflow and outflow vessels. Each lobe, on separate perfusion machines, was subjected to normothermic perfusion using an artificial hemoglobin-based oxygen carrier solution for 6 h. Metabolic parameters as well as hepatic artery and portal vein perfusion parameters monitored. Results: Trends in hepatic artery and portal vein flows showed a general increase in both lobes throughout each perfusion experiment, even when normalized for tissue weight. Progressive decreases in perfusate lactate and glucose levels exhibited comparable trends in between lobes. Conclusion: Our results demonstrate comparability between right and left lobes when simultaneously subjected to normothermic machine perfusion. In the pre-clinical setting, this model provides the ideal comparative controls in the investigation of therapeutic interventions.

Treatment Strategies for the Optimal Management of Locally Advanced Pancreatic Adenocarcinoma With Curative Intent: A Systematic Review.

Historically, locally advanced pancreatic adenocarcinoma (LAPDAC) was considered a palliative condition. Advances in treatment have resulted in studies reporting survival after neoadjuvant treatment and surgery similar to earlier disease stages. However, there is no consensus on optimal LAPDAC management. Our aim was a systematic review of published evidence on LAPDAC treatment strategies with curative intent. Twenty-eight studies defining LAPDAC as per established criteria and reporting outcomes after neoadjuvant treatment with a view to resection were included. Primary outcomes were resection rate and proportion of curative resections. Secondary outcomes were postoperative mortality, progression-free survival, and overall survival. Neoadjuvant treatment varied significantly, most common being the combination of folinic acid, fluorouracil, irontecan, and oxaliplatin. Median percentage of patients proceeding to surgery after completion of neoadjuvant pathway was 33.5%. Median resection rate was 25%. Median R0 resection was 80% of resected patients. These outcomes ranged 0% to 100% across studies. Ninety-day postoperative mortality ranged from 0% to 5%. Median progression-free and overall survival for resected patients were 12.9 and 30 months, respectively, versus 13.2 months overall survival for unresected patients. In conclusion, although there is wide variability in reported LAPDAC resection rates post-neoadjuvant chemotherapy, retrospective data suggest that neoadjuvant treatment followed by surgery results in improved survival.

Pancreatic exocrine insufficiency after pancreaticoduodenectomy: Current evidence and management.

Pancreaticoduodenectomy (PD) is the commonest procedure performed for pancreatic cancer. Pancreatic exocrine insufficiency (PEI) may be caused or exacerbated by surgery and remains underdiagnosed and undertreated. The aim of this review was to ascertain the incidence of PEI, its consequences and management in the setting of PD for indications other than chronic pancreatitis. A literature search of databases (MEDLINE, EMBASE, Cochrane and Scopus) was carried out with the MeSH terms "pancreatic exocrine insufficiency" and "Pancreaticoduodenectomy". Studies that analysed PEI and its complications in the setting of PD for malignant and benign disease were included. Studies reporting PEI in the setting of PD for chronic pancreatitis, conference abstracts and reviews were excluded. The incidence of PEI approached 100% following PD in some series. The pre-operative incidence varied depending on the characteristics of the patient cohort and it was higher (46%-93%) in series where pancreatic cancer was the predominant indication for surgery. Variability was also recorded with regards to the method used for the diagnosis and evaluation of pancreatic function and malabsorption. Pancreatic enzyme replacement therapy is the mainstay of the management. PEI is common and remains undertreated after PD. Future studies are required for the identification of a well-tolerated, reliable and reproducible diagnostic test in this setting.

Correction: The impact on the bioenergetic status and oxidative-mediated tissue injury of a combined protocol of hypothermic and normothermic machine perfusion using an acellular haemoglobin-based oxygen carrier: The cold-to-warm machine perfusion of the liver.

[This corrects the article DOI: 10.1371/journal.pone.0224066.].

Transplantation of discarded livers following viability testing with normothermic machine perfusion.

There is a limited access to liver transplantation, however, many organs are discarded based on subjective assessment only. Here we report the VITTAL clinical trial (ClinicalTrials.gov number NCT02740608) outcomes, using normothermic machine perfusion (NMP) to objectively assess livers discarded by all UK centres meeting specific high-risk criteria. Thirty-one livers were enroled and assessed by viability criteria based on the lactate clearance to levels ≤2.5 mmol/L within 4 h. The viability was achieved by 22 (71%) organs, that were transplanted after a median preservation time of 18 h, with 100% 90-day survival. During the median follow up of 542 days, 4 (18%) patients developed biliary strictures requiring re-transplantation. This trial demonstrates that viability testing with NMP is feasible and in this study enabled successful transplantation of 71% of discarded livers, with 100% 90-day patient and graft survival; it does not seem to prevent non-anastomotic biliary strictures in livers donated after circulatory death with prolonged warm ischaemia.

Systematic Review: Clinical Metabolomics to Forecast Outcomes in Liver Transplantation Surgery.

Liver transplantation is an effective intervention for end-stage liver disease, fulminant hepatic failure, and early hepatocellular carcinoma. Yet, there is marked patient-to-patient variation in liver transplantation outcomes. This calls for novel diagnostics to enable rational deployment of donor livers. Metabolomics is a postgenomic high-throughput systems biology approach to diagnostic innovation in clinical medicine. We report here an original systematic review of the metabolomic studies that have identified putative biomarkers in the context of liver transplantation. Eighteen studies met the inclusion criteria that involved sampling of blood (n = 4), dialysate fluid (n = 4), bile (n = 5), and liver tissue (n = 5). Metabolites of amino acid and nitrogen metabolism, anaerobic glycolysis, lipid breakdown products, and bile acid metabolism were significantly different in transplanted livers with and without graft dysfunction. However, criteria for defining the graft dysfunction varied across studies. This systematic review demonstrates that metabolomics can be deployed in identification of metabolic indicators of graft dysfunction with a view to implicated molecular mechanisms. We conclude the article with a horizon scanning of metabolomics technology in liver transplantation and its future prospects and challenges in research and clinical practice.

The impact on the bioenergetic status and oxidative-mediated tissue injury of a combined protocol of hypothermic and normothermic machine perfusion using an acellular haemoglobin-based oxygen carrier: The cold-to-warm machine perfusion of the liver.

INTRODUCTION: The combination of hypothermic and normothermic machine perfusion (HMP+NMP) of the liver provides individual benefits of both techniques, improving the rescue of marginal organs. The aim of this study was to investigate the effect on the bioenergetic status and the oxidative-mediated tissue injury of an uninterrupted combined protocol of HMP+NMP using a single haemoglobin-based oxygen carrier (HBOC)-based perfusate. METHODS: Ten discarded human donor livers had either 2 hours of dual hypothermic oxygenated perfusion (D-HOPE) with sequential controlled rewarming (COR) and then NMP using the HBOC-based perfusate uninterruptedly (cold-to-warm group); or 2 hours of hypothermic oxygenated perfusion (HOPE) with an oxygen carrier-free perfusate, followed by perfusate exchange and then NMP with an HBOC-based perfusate. Markers of liver function, tissue adenosine triphosphate (ATP) levels and tissue injury were systematically assessed. RESULTS: The hypothermic phase downregulated mitochondrial respiration and increased ATP levels in both groups. The cold-to-warm group presented higher arterial vascular resistance during rewarming/NMP (p = 0.03) with a trend of lower arterial flow (p = 0.09). At the end of NMP tissue expression of markers of reactive oxygen species production, oxidative injury and inflammation were comparable between the groups. CONCLUSION: The uninterrupted combined protocol of HMP+NMP using an HBOC-based perfusate-cold-to-warm MP-mitigated the oxidative-mediated tissue injury and enhanced hepatic energy stores, similarly to an interrupted combined protocol; however, it simplified the logistics of this combination and may favour its clinical applicability.

Impact of machine perfusion of the liver on post-transplant biliary complications: A systematic review.

AIM: To review the clinical impact of machine perfusion (MP) of the liver on biliary complications post-transplantation, particularly ischaemic-type biliary lesions (ITBL). METHODS: This systematic review was performed in accordance with the Preferred Reporting Systematic Reviews and Meta-Analysis (PRISMA) protocol. The following databases were searched: PubMed, MEDLINE and Scopus. The keyword "liver transplantation" was used in combination with the free term "machine perfusion". Clinical studies reporting results of transplantation of donor human livers following ex situ or in situ MP were analysed. Details relating to donor characteristics, recipients, technique of MP performed and post-operative biliary complications (ITBL, bile leak and anastomotic strictures) were critically analysed. RESULTS: Fifteen articles were considered to fit the criteria for this review. Ex situ normothermic MP was used in 6 studies, ex situ hypothermic MP in 5 studies and the other 4 studies investigated in situ normothermic regional perfusion (NRP) and controlled oxygenated rewarming. MP techniques which have per se the potential to alleviate ischaemia-reperfusion injury: Such as hypothermic MP and NRP, have also reported lower rates of ITBL. Other biliary complications, such as biliary leak and anastomotic biliary strictures, are reported with similar incidences with all MP techniques. There is currently less clinical evidence available to support normothermic MP as a mitigator of biliary complications following liver transplantation. On the other hand, restoration of organ to full metabolism during normothermic MP allows assessment of hepatobiliary function before transplantation, although universally accepted criteria have yet to be validated. CONCLUSION: MP of the liver has the potential to have a positive impact on post-transplant biliary complications, specifically ITBL, and expand extended criteria donor livers utilisation.

Laparoscopic Right Hemicolectomy in an Automated Peritoneal Dialysis Patient without Removal of the PD Catheter: A Case Report.

Introduction. Laparotomy in patients on peritoneal dialysis (PD) is associated with an increased risk of morbidity. Furthermore, standard protocol recommends removal of the PD catheter when surgery on the intestine is required. As far as we are aware, this is the first case report of laparoscopic right hemicolectomy in a patient on automated PD where the PD catheter was left in situ. Case Report. A 61-year-old man man on APD who presented with a caecal carcinoma was stabilised on temporary haemodialysis (HD) prior to undergoing a laparoscopic right hemicolectomy without removal of the PD catheter. He made an uneventful recovery and APD was resumed successfully 2 weeks after surgery. Discussion. PD patients undergoing intra-abdominal surgery are at increased risk of complications. While the benefits of laparoscopic surgery in the standard surgical population are well established, there is limited experience of the technique in PD patients. Possible advantages could theoretically be early resumption of PD as well as less PD failure due to the formation of adhesions. Conclusion. Our experience with this case indicates that laparoscopic right hemicolectomy in a background of PD can be undertaken without removal of the PD catheter and is associated with early resumption of PD.