Abdominal Normothermic Regional Perfusion in Donation After Circulatory Death: A Systematic Review and Critical Appraisal

Background: Abdominal normothermic regional perfusion (aNRP) for donation after circulatory death is an emerging organ preservation technique that might lead to increased organ utilization per donor by facilitating viability testing, improving transplant outcome by early reversal of ischemia, and decreasing the risk of unintentional surgical damage. The aim of the current review is to evaluate the recent literature on the added value of aNRP when compared to local standard perfusion technique.Methods: The Preferred Reporting Items for Systematic reviews and Meta-Analyses guideline for systematic reviews was used, and relevant literature databases were searched. Primary outcomes were organ utilization rate and patient and graft survival after 1 year. Secondary outcomes included delayed graft function, primary nonfunction, serum creatinine, and biliary complications.Results: A total of 24 articles were included in this review. The technique is unanimously reported to be feasible and safe, but the available studies are characterized by considerable heterogeneity and bias.Conclusions: Uniform reported outcome measures are needed to draw more definitive conclusions on transplant outcomes and organ utilization. A randomized controlled trial comparing aNRP with standard procurement technique in donation after circulatory death donors would be needed to show the added value of the procedure and determine its place among modern preservation techniques.Transplant surger

The challenge of quality assessment and regional perfusion to increase donor organ utilisation

This thesis has studied several modalities how to increase the organ utilisation rate. The results in this thesis indicate that the acceptance of kidneys with acute kidney injury stage 1 or 2 will significantly contribute to the donor pool as AKI kidneys have comparable outcomes and should therefore not be discarded. Clinically relevant biomarkers such as cell-free unmethylated-INS DNA, FMN, GSN, IGFBP3 and IGF2R were identified or explored in the first part of this thesis and may, if analysed and/or validated thoroughly, contribute to a better assessment of organ viability supporting the justified decision whether to accept or decline the donor organ.The second part of this thesis describes different aspects of the organ preservation technique of abdominal normothermic regional perfusion (aNRP). This relatively new machine perfusion technique has been shown to be feasible and safe, however, consensus regarding assessment parameters during perfusion, protocols and outcome measurements is still lacking. Despite of an inspiring surgical enthusiasm and keeninterest to accept this modality as a new standard, a randomised clinical trial is still required and entirely ethically justifiable in order to scientifically demonstrate superiority of this method for each individual abdominal organ comparing it to other successful (ex-situ) preservation and perfusion strategies. If aNRP can be shown to obtain better post transplantation outcomes whilst increasing organ utilisation, it may be the least complex and most cost-effective strategy in organ preservation. On the other hand, aNRP will only be used in DCD donors. As such, uncertainty regarding the quality of higher risk organs from DBD donors will still be evaluated ex-situ during cold and/or warm machine perfusion with the potential to repair or even regenerate injured organs and making them ‘transplantable’ again.LUMC / Geneeskund

Donor eligibility criteria and liver graft acceptance criteria during normothermic regional perfusion: A systematic review

Acceptance of liver grafts from donations after circulatory death (DCD) largely remains a "black box," particularly due to the unpredictability of the agonal phase. Abdominal normothermic regional perfusion (aNRP) can reverse ischemic injury early during the procurement procedure, and it simultaneously enables graft viability testing to unravel this black box. This review evaluates current protocols for liver viability assessment to decide upon acceptance or decline during aNRP. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was used, and relevant literature databases were searched. The primary outcome consisted of criteria for liver graft viability assessment. Secondary outcomes included survival, primary nonfunction (PNF), early dysfunction, and biliary complications. A total of 14 articles were included in the analysis. In all protocols, a combination of criteria was used to assess suitability of the liver for transplantation. As many as 12 studies (86%) used macroscopic assessment, 12 studies (86%) used alanine transaminase (ALT) levels in perfusate, 9 studies (64%) used microscopic assessment, and 7 studies (50%) used lactate levels as assessment criteria. The organ utilization rate (OUR) was 16% for uncontrolled donation after circulatory death (uDCD) and 64% for controlled donation after circulatory death (cDCD). The most used acceptation criterion in uDCD is ALT level (31%), while in cDCD macroscopic aspect (48%) is most used. Regarding postoperative complications, PNF occurred in 13% (6%-25%) of uDCD livers and 3% (2%-4%) of cDCD livers. In uDCD, the 1-year graft and patient survival rates were 75% (66%-82%) and 82% (75%-88%). In cDCD, the 1-year graft and patient survival rates were 91% (89%-93%) and 93% (91%-94%), respectively. In conclusion, the currently used assessment criteria consist of macroscopic aspect and transaminase levels. The acceptance criteria should be tailored according to donor type to prevent an unacceptable PNF rate in uDCD and to increase the relatively modest OUR in cDCD

Quantification of Unmethylated Insulin DNA Using Methylation Sensitive Restriction Enzyme Digital Polymerase Chain Reaction

Assessment of specific beta-cell death can be used to determine the quality and viability of pancreatic islets prior to transplantation and hence predict the suitability of the pancreas for isolation. Recently, several groups have demonstrated that unmethylated insulin (INS)-DNA is correlated to beta-cell death in type 1 diabetes patients and during clinical islet isolation and subsequent transplantation. Here, we present a step-by-step protocol of our novel developed method for quantification of the relative amount of unmethylated INS-DNA using methylation sensitive restriction enzyme digital polymerase chain reaction This method provides a novel and sensitive way to quantify the relative amount of beta-cell derived unmethylated INS-DNA in cellular lysate. We therefore suggest that this technique can be of value to reliably determine the purity of an islet preparation and may also serve as a measure of the quality of islets prior to transplantation measuring unmethylated INS-DNA as a reflection of the relative amount of lysed beta-cells.Nephrolog

Quantification of Unmethylated Insulin DNA Using Methylation Sensitive Restriction Enzyme Digital Polymerase Chain Reaction

Assessment of specific beta-cell death can be used to determine the quality and viability of pancreatic islets prior to transplantation and hence predict the suitability of the pancreas for isolation. Recently, several groups have demonstrated that unmethylated insulin (INS)-DNA is correlated to beta-cell death in type 1 diabetes patients and during clinical islet isolation and subsequent transplantation. Here, we present a step-by-step protocol of our novel developed method for quantification of the relative amount of unmethylated INS-DNA using methylation sensitive restriction enzyme digital polymerase chain reaction This method provides a novel and sensitive way to quantify the relative amount of beta-cell derived unmethylated INS-DNA in cellular lysate. We therefore suggest that this technique can be of value to reliably determine the purity of an islet preparation and may also serve as a measure of the quality of islets prior to transplantation measuring unmethylated INS-DNA as a reflection of the relative amount of lysed beta-cells

Salvage of Declined Extended-criteria DCD Livers Using In Situ Normothermic Regional Perfusion

Objective: This study investigates whether liver grafts donated after circulatory death (DCD) that are declined by the entire Eurotransplant region can be salvaged with abdominal normothermic regional perfusion (aNRP). Background: aNRP is increasingly used for DCD liver grafts because it prevents typical complications. However, it is unclear whether aNRP is capable to rescue pretransplant declined liver grafts by providing the opportunity to test function during donation. Methods: Donor livers from DCD donors, declined by all centers in the Eurotransplant region, were included for this study. The comparator cohort included standard DCD livers and livers donated after brain death, transplanted in the same time period. Results: After the withdrawal of life-sustaining treatment, 28 from the 43 donors had a circulatory death within 2 hours, in which case aNRP was initiated. Of these 28 cases, in 3 cases perfusion problems occurred, 5 grafts were declined based on liver assessment, and 20 liver grafts were transplanted. The main differences during aNRP between the transplanted grafts and the assessed nontransplanted grafts were alanine transaminase levels of 53 U/L (34-68 U/L) versus 367 U/L (318-488 U/L) (P=0.001) and bile production in 100% versus 50% of the grafts (P=0.024). The 12-month graft and patient survival were both 95%, similar to the comparator cohort. The incidence of ischemic cholangiopathy was 11%, which was lower than in the standard DCD cohort (18%). Conclusion: aNRP can safely select and thus is able to rescue DCD liver grafts that were deemed unsuitable for transplantation, while preventing primary nonfunction and minimizing ischemic cholangiopathy

The role of flavin mononucleotide (FMN) as a potentially clinically relevant biomarker to predict the quality of kidney grafts during hypothermic (oxygenated) machine perfusion

Hypothermic machine perfusion (HMP) provides preservation superior to cold storage and may allow for organ assessment prior to transplantation. Since flavin mononucleotide (FMN) in perfusate has been proposed as a biomarker of organ quality during HMP of donor livers, the aim of this study was to validate FMN as a biomarker for organ quality in the context of HMP preserved kidneys. Perfusate samples (n = 422) from the paired randomised controlled COPE-COMPARE-trial, comparing HMP with oxygenation (HMPO2) versus standard HMP in kidneys, were used. Fluorescence intensity (FI) was assessed using fluorescence spectroscopy (excitation 450nm; emission 500-600nm) and validated by fluorospectrophotometer and targeted liquid chromatography mass spectrometry (LC-MS/MS). Fluorescence intensity (FI)((ex450;em500-600)) increased over time during machine perfusion in both groups (p<0.0001). This increase was similar for both groups (p = 0.83). No correlation, however, was found between FI(ex450;em500-600) and post-transplant outcomes, including day 5 or 7 serum creatinine (p = 0.11; p = 0.16), immediate graft function (p = 0.91), creatinine clearance and biopsy-proven rejection at one year (p = 0.14; p = 0.59). LC-MS/MS validation experiments of samples detected FMN in only one perfusate sample, whilst the majority of samples with the highest fluorescence (n = 37/38, 97.4%) remained negative. In the context of clinical kidney HMP, fluorescence spectroscopy unfortunately appears to be not specific and probably unsuitable for FMN. This study shows that FMN does not classify as a clinically relevant predictive biomarker of kidney graft function after transplantation.Transplant surger