The use of extracorporeal membranous oxygenation in donors after cardiac death:

Current practice and novel approaches in organ preservation

Organ transplantation remains the only treatment option for patients with end-stage organ failure. The last decade has seen a flurry of activity in improving organ preservation technologies, which promise to increase utilization in a dramatic fashion. They also bring the promise of extending the preservation duration significantly, which opens the doors to sharing organs across local and international boundaries and transforms the field. In this work, we review the recent literature on machine perfusion of livers across various protocols in development and clinical use, in the context of extending the preservation duration. We then review the next generation of technologies that have the potential to further extend the limits and open the door to banking organs, including supercooling, partial freezing, and nanowarming, and outline the opportunities arising in the field for researchers in the short and long term.

Deceased donor kidney procurement: Systematic review of the surgical technique

INTRODUCTION

Kidney procurement procedure must be carried out following a standardized technique in order to optimize kidney grafts for their subsequent implantation.

OBJECTIVES

Review of the available literature on kidney procurement procedure.

MATERIAL AND METHODS

Narrative review of the available evidence on deceased donor kidney procurement technique after a search of relevant manuscripts indexed in PubMed, EMBASE and Scielo written in English and Spanish.

RESULTS

Deceased donor kidney procurement can be divided into two groups, donation after brain death (DBD) and donation after circulatory death (DCD). Kidney procurement in DBD frequently includes other chest and/or abdominal organs, requiring multidisciplinary surgical coordination. During the harvesting procedure, the renal vascular pedicle must remain intact for subsequent implantation and reduced ischemia time.

CONCLUSIONS

Adequate execution and perfect knowledge of the technique for surgical removal and anatomy reduces the rate of graft losses associated to inadequate harvesting techniques.

Normothermic regional perfusion in liver transplantation from donation after cardiocirculatory death: Technical, biochemical, and regulatory aspects and review of literature

BACKGROUND

Organs from donation after circulatory death (DCD) are increasingly used for liver transplantation, due to the persisting organ shortage and waiting list mortality. However, the use of DCD grafts is still limited by the inferior graft survival rate and the increased risk of primary non-function and biliary complications when compared to brain death donors' grafts.

METHODS

Abdominal normothermic regional perfusion with extracorporeal membrane oxygenation (ECMO) is an in situ preservation strategy. which may mitigate ischemia-reperfusion injuries. and has been proposed to restore blood perfusion after the determination of death thus optimizing liver function before implantation.

RESULTS

In this systematic review, we highlighted the clinical evidence supporting the use of normothermic regional perfusion in DCD liver underlying the pathophysiological mechanisms, and technical, logistic, and regulatory aspects.

CONCLUSIONS

Despite the lack of properly designed, prospective, randomized trials, the current available data suggest beneficial effects of normothermic regional perfusion on clinical outcomes after liver transplantation.

Comparison of in situ preservation techniques for kidneys from donors after circulatory death: a systematic review and meta-analysis

Background

Several techniques have been developed to reduce the warm ischaemic injury of donation after circulatory death (DCD) organs before procurement. There are scarce data about the in situ preservation techniques for kidney graft outcomes. The aim of this systematic review was to evaluate the best in situ preservation method for kidney graft outcomes from organs obtained from controlled and uncontrolled DCD.

Methods

A systematic review of the PubMed (MEDLINE), Embase, LILACS and Cochrane databases was conducted. Studies that compare two or more in situ preservation techniques were identified and included. Only studies which provided enough data to calculate odds ratio were eligible for meta-analysis. PROSPERO registration: CRD42020179598.

Results

The search strategy yielded 7,121 studies. Ultimately, 14 retrospective studies were included. Because of heterogeneity, the included studies provided weak evidence that normothermic regional perfusion (NRP) is the best in situ preservation technique in terms of delayed graft function (DGF) rates. Regarding primary nonfunction (PNF), we carried out a meta-analysis of 10 studies with a pooled OR of 0.83 (95% CI: 0.40-1.71), for the NRP. In regard to DGF, pooled OR for NRP was 0.36 (95% CI: 0.25-0.54).

Conclusions

NRP in the DCD donor could improve kidney graft function and be considered the in situ preservation technique of choice for abdominal organs.

Kidney Transplants in Controlled Donation Following Circulatory Death, or Maastricht Type III Donors, With Abdominal Normothermic Regional Perfusion, Optimizing Functional Outcomes

Supplemental Digital Content is available in the text.

Background.

Warm ischemia time and ischemia-reperfusion damage result in higher rates of delayed graft function and primary nonfunction in kidney transplants (KTs) from controlled donation after circulatory death (cDCD). This study aimed to assess early and late kidney function and patient and graft survival of KT from cDCD preserved with normothermic regional perfusion (NRP) and to compare with KT from brain death donors (DBDs) and cDCD preserved with rapid recovery (RR).

Methods.

Patients who received a KT at our institution from 2012 to 2018 were included, with a minimum follow-up period of 1 y. They were categorized by donor type and conditioning methods: DBD, cDCD with NRP, and cDCD with RR. Early and late graft function, along with patient and graft survival were analyzed in all groups.

Results.

A total of 182 KT recipients were included in the study (98 DBD and 84 cDCD). Out of the cDCDs, 24 kidneys were recovered with the use of NRP and 62 with RR; 22 of the 24 kidneys were ultimately transplanted. The cDCD using NRP group showed lower rates of delayed graft function compared with the cDCD with RR group (36.3% versus 46.7%, P = 0.01). Also, primary nonfunction rates were lower in the cDCD using NRP group (4.5% versus 6.4% cDCD-RR and 10.2% DBD). Patient survival rates were >90% in all groups. No differences were found in graft survival rates at 1 y.

Conclusions.

The use of abdominal NRP improves early function recovery of KT from cDCD, making their outcomes comparable with those of DBD.

Targeting oxidative stress, a crucial challenge in renal transplantation outcome

Disorders characterized by ischemia/reperfusion (I/R) are the most common causes of debilitating diseases and death in stroke, cardiovascular ischemia, acute kidney injury or organ transplantation. In the latter example the I/R step defines both the amplitude of the damages to the graft and the functional recovery outcome. During transplantation the kidney is subjected to blood flow arrest followed by a sudden increase in oxygen supply at the time of reperfusion. This essential clinical protocol causes massive oxidative stress which is at the basis of cell death and tissue damage. The involvement of both reactive oxygen species (ROS) and nitric oxides (NO) has been shown to be a major cause of these cellular damages. In fact, in non-physiological situations, these species escape endogenous antioxidant control and dangerously accumulate in cells. In recent years, the objective has been to find clinical and pharmacological treatments to reduce or prevent the appearance of oxidative stress in ischemic pathologies. This is very relevant because, due to the increasing success of organ transplantation, clinicians are required to use limit organs, the preservation of which against oxidative stress is crucial for a better outcome. This review highlights the key actors in oxidative stress which could represent new pharmacological targets.

Evaluation of Liver Quality after Circulatory Death Versus Brain Death: A Comparative Preclinical Pig Model Study

The current organ shortage in hepatic transplantation leads to increased use of marginal livers. New organ sources are needed, and deceased after circulatory death (DCD) donors present an interesting possibility. However, many unknown remains on these donors and their pathophysiology regarding ischemia reperfusion injury (IRI). Our hypothesis was that DCD combined with abdominal normothermic regional recirculation (ANOR) is not inferior to deceased after brain death (DBD) donors. We performed a mechanistic comparison between livers from DBD and DCD donors in a highly reproducible pig model, closely mimicking donor conditions encountered in the clinic. DCD donors were conditioned by ANOR. We determined that from the start of storage, pro-lesion pathways such as oxidative stress and cell death were induced in both donor types, but to a higher extent in DBD organs. Furthermore, pro-survival pathways, such as resistance to hypoxia and regeneration showed activation levels closer to healthy livers in DCD-ANOR rather than in DBD organs. These data highlight critical differences between DBD and DCD-ANOR livers, with an apparent superiority of DCD in terms of quality. This confirms our hypothesis and further confirms previously demonstrated benefits of ANOR. This encourages the expended use of DCD organs, particularly with ANOR preconditioning.

Kidney Transplant From Uncontrolled Donation After Circulatory Death: Contribution of Normothermic Regional Perfusion

BACKGROUND

The French uncontrolled donors after circulatory death (DCD) protocol restricts donor age to <55 years, no-flow time to <30 minutes, and functional warm ischemia time to <150 minutes. In situ kidney perfusion can be performed at either 4°C (in situ cooling [ISC]) or 33-36°C (normothermic regional perfusion [NRP]). Hypothermic machine perfusion is systematically used. Only nonimmunized first transplant recipients were eligible. To improve the management of uncontrolled DCD, we tried to identify factors predictive of outcome.

METHODS

We identified all kidney transplants from uncontrolled DCD between 2007 and 2014 from the French Transplant Registry. Risk factors for primary nonfunction (PNF; n = 37) and poor renal function (estimated glomerular filtration rate < 30 mL/min or graft loss at 1 y, n = 66) were analyzed by using a multivariate logistic model.

RESULTS

This study analyzed 499 kidney transplantations, 50% of which were performed with NRP. Mean functional warm ischemia time was 135 minutes. Mean cold ischemia time was 14 hours. The principal PNF risk factor was young donor age (odds ratio [OR] = 0.95; P = 0.002). A sensitivity analysis showed a higher risk of PNF with ISC than with NRP (OR = 4.5; P = 0.015). Risk factors for poor renal function were donor body mass index (OR = 1.2; P < 0.001) and ISC versus NRP. Univariate analysis of uncontrolled DCD-specific risk factors showed no-flow time, functional warm time, and cold ischemia time did not affect the risk of PNF or poor renal function.

CONCLUSIONS

Uncontrolled DCD kidneys are an additional source of valuable transplants. NRP appears to decrease graft failure by restoring oxygenated blood as the first step of preconditioning.

Delayed graft function and perfusion parameters of kidneys from uncontrolled donors after circulatory death

Better preservation and evaluation of kidneys from donors after circulatory death serve to increase the number of kidneys available for transplantation and hypothermic machine perfusion has been shown to decrease ischemia reperfusion injury and delayed graft function. Data on relation between hemodynamic parameters during hypothermic machine perfusion and delayed graft function in kidneys from donors after circulatory death are so far scarce and not univocal. We aimed at assessing whether hemodynamic parameters measured during hypothermic machine perfusion (flow, mean perfusion pressure, and renal resistance) are associated with delayed graft function in 26 kidneys retrieved from uncontrolled donors after circulatory death. In our series, the incidence of delayed graft function was 57.7% (15/26). Recipients who developed delayed graft function had a longer warm ischemic time (p = 0.04). All hemodynamic parameters measured during hypothermic machine perfusion were comparable between recipients with delayed graft function and those without. According to our data, in kidneys from uncontrolled donors after circulatory death, a longer warm ischemic time (that is the overall time of no flow, as the sum of the no-flow and the no-touch period) is associated with delayed graft function. This finding underscores the pivotal role of ischemic injury in terms of absence of flow in affecting graft function. No association was detectable between hemodynamic parameters during hypothermic machine perfusion and the development of delayed graft function in our series.

[Ischemia-reperfusion injury after kidney transplantation]

Ischemia-reperfusion injury is an inescapable phenomenon in kidney transplantation. It combines lesional processes of biochemical origin associated with oxydative stress and of immunological origin in connection with the recruitment and activation of innate immunity cells. Histological lesions associate acute tubular necrosis and interstitial œdema, which can progress to interstitial fibrosis. The extent of these lesions depends on donor characteristics (age, expanded criteria donor, etc.) and cold ischemia time. In the short term, ischemia-reperfusion results in delayed recovery of graft function. Cold ischemia time also impacts long-term graft survival. Preclinical models, such as murine and porcine models, have furthered understanding of the pathophysiological mechanisms of ischemia-reperfusion injury. Due to its renal anatomical proximity to humans, the porcine model is relevant to assessment of the molecules administered to a donor or recipient, and also of additives to preservation solutions. Different donor resuscitation and graft perfusion strategies can be studied. In humans, prevention of ischemia-reperfusion injury is a research subject as concerns donor conditioning, additive molecules in preservation solutions, graft reperfusion modalities and choice of the molecules administered to the recipient. Pending significant advances in research, the goal is to achieve the shortest possible cold ischemia time.

Normothermic extracorporeal membrane oxygenation support: Improving the function of intestinal grafts obtained from cardiac death donors

Extracorporeal membrane oxygenation (ECMO) could ameliorate the energy status and viability of bowel grafts from cardiac death donors. However, the function of these grafts after transplantation is not clear. The purpose of the study was to evaluate the early function of intestinal grafts after transplantation from expected cardiac death donors supported with normothermic extracorporeal support using a porcine allogeneic orthotopic segmental small bowel transplantation model. Eighteen domestic crossbred donor pigs were assigned to living donation (LD), donation after cardiac death (DCD), and ECMO groups. In the LD group, small bowels were harvested and preserved immediately in cold storage. In the other two groups, the donor pigs received conventional rapid recovery treatment or 1-hour normothermic extracorporeal support after 10-minutes expected cardiac arrest. Subsequently, the small bowels were removed and preserved in cold storage. After 5-6 hours of preservation, small bowel grafts were transplanted into the recipient pigs that underwent enterectomy. The pathology and electron microscopy results, cell apoptosis rate, tight junction protein expression level in the intestinal mucosa, and plasma endotoxin level were evaluated after transplantation. All grafts functioned on the basis of the maltose absorption test results at day 7 after transplantation. There were no significant differences in the morphological changes in the intestinal mucosa among the three groups at day 7 after transplantation. The cell apoptosis rate and plasma endotoxin level in the ECMO group did not differ significantly than those in the LD group, but were evidently lower than those in the DCD group (P < .001). The intestinal absorptive function improved significantly in the ECMO group in contrast with that in the DCD group (P < .001). Short-term ECMO intervention can alleviate ischemia-reperfusion injuries in intestinal grafts and improve intestinal absorptive function in the early stage after transplantation. Reducing caspase-3 protein expression and cell apoptosis in the intestinal mucosa may be one of the protective mechanisms of ECMO intervention.

Combined lung and liver procurement in controlled donation after circulatory death using normothermic abdominal perfusion. Initial experience in two Spanish centers

Combining simultaneously lung and liver procurement in controlled donation after circulatory death (cDCD) using normothermic abdominal perfusion (NRP) for abdominal grafts and cooling and rapid recovery technique (RR) for the lungs increases the complexity of the procurement procedure and might injure the grafts. A total of 19 cDCDs from two centers using this combined procedure were evaluated, and 16 liver and 21 lung transplantations were performed. As controls, 34 donors after brain death (DBDs) were included (29 liver and 41 lung transplantations were performed). Two cDCD liver recipients developed primary nonfunction (12.5%). No cases of ischemic cholangiopathy were observed among cDCD recipients. The 1-year and 2-year liver recipients survival was 87.5% and 87.5% for the cDCD group, and 96% and 84.5% for the DBD group, respectively (P = .496). The 1-year and 2-year lung recipients survival was 84% and 84% for the cDCD group and 90% and 90% for the DBD group, respectively (P = .577). This is the largest experience ever reported in cDCD with the use of NRP combined with RR of the lungs. This combined method offers an outstanding recovery rate and liver and lung recipients survival comparable with those transplanted with DBDs. Further studies are needed to confirm our findings.

Preventing acute kidney injury during transplantation: the application of novel oxygen carriers

INTRODUCTION

Delayed graft function (DGF) has a significant impact on kidney transplantation outcome. One of the underlying pivotal mechanisms is organ preservation and associated hypothermia and biochemical alteration.

AREAS COVERED

This paper focuses on organ preservation and its clinical consequences and describes 1. A comprehensive presentation of the pathophysiological mechanism involved in delayed graft function development; 2. The impact on endothelial cells and microvasculature integrity and the consequences on transplanted organ outcome; 3. The reassessment of dynamic organ preservation motivated by the growing use of extended criteria donors and the interest in the potential of normothermia; 4. The role of oxygenation during dynamic preservation; and 5. Novel oxygen carriers and their proof of concept in transplantation, among which M101 (HEMO₂life®) is currently the most extensively investigated.

EXPERT OPINION

Metabolic disturbances and imbalance of oxygen supply during preservation highlight the importance of providing oxygen. Normothermia, permitted by recent advances in machine perfusion technology, appears to be the leading edge of preservation technology. Several oxygen transporters are compatible with normothermia; however, only M101 also demonstrates compatibility with standard hypothermic preservation.

In situ normothermic perfusion of livers in controlled circulatory death donation may prevent ischemic cholangiopathy and improve graft survival

Livers from controlled donation after circulatory death (DCD) donors suffer a higher incidence of nonfunction, poor function, and ischemic cholangiopathy. In situ normothermic regional perfusion (NRP) restores a blood supply to the abdominal organs after death using an extracorporeal circulation for a limited period before organ recovery. We undertook a retrospective analysis to evaluate whether NRP was associated with improved outcomes of livers from DCD donors. NRP was performed on 70 DCD donors from whom 43 livers were transplanted. These were compared with 187 non-NRP DCD donor livers transplanted at the same two UK centers in the same period. The use of NRP was associated with a reduction in early allograft dysfunction (12% for NRP vs. 32% for non-NRP livers, P = .0076), 30-day graft loss (2% NRP livers vs. 12% non-NRP livers, P = .0559), freedom from ischemic cholangiopathy (0% vs. 27% for non-NRP livers, P < .0001), and fewer anastomotic strictures (7% vs. 27% non-NRP, P = .0041). After adjusting for other factors in a multivariable analysis, NRP remained significantly associated with freedom from ischemic cholangiopathy (P < .0001). These data suggest that NRP during organ recovery from DCD donors leads to superior liver outcomes compared to conventional organ recovery.

Introducing of the First DCD Kidney Transplantation Program in Poland

In many countries, including Poland, the main problem with transplantation is the insufficiency of organ donors in relation to the demand for organs. Hence, the common aim globally is to increase the pool of donors. The prolonged survival of patients after transplantation, with respect to the survival time of patients on dialysis, makes the search much more intense. After the recourse of expanded criteria donors (ECD), the next step was obtaining kidneys from donors after irreversible cardiac death (DCD). Therefore, based on Dutch, British, and Spanish experience, it can be hypothesized that the introduction of DCD procedures in countries that have not launched these programs and the improvement of DCD procedures may shorten the waiting time for organ transplantation globally. The legal basis for the procurement of organs after irreversible cardiac arrest came into existence in Poland in 2010. Previously, such organ procurements were not in practice. Since 1984, when Poland published irreversible cardiac arrest as a criterion of brain death, it became the only way to determine death prior to the procurement of organs. The aim of this report was to evaluate the results of the first 19 transplantation cases involving harvested kidneys from donors after cardiac arrest, which was irreversible and clinically confirmed, without any doubt as per the ethical protocol of DCD. Understanding, support, and public perception are essential for this program's initiation and maintenance.

Defining the optimal duration for normothermic regional perfusion in the kidney donor: A porcine preclinical study

Kidneys from donation after circulatory death (DCD) are highly sensitive to ischemia-reperfusion injury and thus require careful reconditioning, such as normothermic regional perfusion (NRP). However, the optimal NRP protocol remains to be characterized. NRP was modeled in a DCD porcine model (30 minutes of cardiac arrest) for 2, 4, or 6 hours compared to a control group (No-NRP); kidneys were machine-preserved and allotransplanted. NRP appeared to permit recovery from warm ischemia, possibly due to an increased expression of HIF1α-dependent survival pathway. At 2 hours, blood levels of ischemic injury biomarkers increased: creatinine, lactate/pyruvate ratio, LDH, AST, NGAL, KIM-1, CD40 ligand, and soluble-tissue-factor. All these markers then decreased with time; however, AST, NGAL, and KIM-1 increased again at 6 hours. Hemoglobin and platelets decreased at 6 hours, after which the procedure became difficult to maintain. Regarding inflammation, active tissue-factor, cleaved PAR-2 and MCP-1 increased by 4-6 hours, but not TNF-α and iNOS. Compared to No-NRP, NRP kidneys showed lower resistance during hypothermic machine perfusion (HMP), likely associated with pe-NRP eNOS activation. Kidneys transplanted after 4 and 6 hours of NRP showed better function and outcome, compared to No-NRP. In conclusion, our results confirm the mechanistic benefits of NRP and highlight 4 hours as its optimal duration, after which injury markers appear.

Donation after circulatory death and its expansion in Spain

PURPOSE OF REVIEW

Donation after circulatory death (DCD) is still performed in a limited number of countries. This article summarizes the development of DCD in Spain and presents recent Spanish contributions to gain knowledge on the potential benefits and the practical use of normothermic regional perfusion (nRP).

RECENT FINDINGS

DCD now contributes to 24% of deceased donors in Spain. The development of DCD has been based on an assessment of practices in the treatment of cardiac arrest and end-of-life care to accommodate the option of DCD; the creation of an adequate regulatory framework; and institutional support, professional training and public education. Appropriate posttransplant outcomes have been obtained with organs from both uncontrolled and controlled DCD donors. nRP is increasingly used, with preliminary data supporting improved results compared with other in-situ preservation/recovery approaches. Mobile teams with portable extracorporeal membrane oxygenation devices are making nRP possible in hospitals without these resources. To avoid the possibility of reestablishing brain circulation after the determination of death, a specific methodology has been validated.

SUMMARY

DCD has been successfully developed in Spain following a streamlined process. nRP may become a standard in DCD, although further evidence on the benefits of this technology is eagerly awaited.

Barriers and Advances in Kidney Preservation

Despite the fact that a significant fraction of kidney graft dysfunctions observed after transplantation is due to ischemia-reperfusion injuries, there is still no clear consensus regarding optimal kidney preservation strategy. This stems directly from the fact that as of yet, the mechanisms underlying ischemia-reperfusion injury are poorly defined, and the role of each preservation parameter is not clearly outlined. In the meantime, as donor demography changes, organ quality is decreasing which directly increases the rate of poor outcome. This situation has an impact on clinical guidelines and impedes their possible harmonization in the transplant community, which has to move towards changing organ preservation paradigms: new concepts must emerge and the definition of a new range of adapted preservation method is of paramount importance. This review presents existing barriers in transplantation (e.g., temperature adjustment and adequate protocol, interest for oxygen addition during preservation, and clear procedure for organ perfusion during machine preservation), discusses the development of novel strategies to overcome them, and exposes the importance of identifying reliable biomarkers to monitor graft quality and predict short and long-term outcomes. Finally, perspectives in therapeutic strategies will also be presented, such as those based on stem cells and their derivatives and innovative models on which they would need to be properly tested.

An integrated program of extracorporeal membrane oxygenation (ECMO) assisted cardiopulmonary resuscitation and uncontrolled donation after circulatory determination of death in refractory cardiac arrest

AIM

To assess the feasibility of an integrated program of extracorporeal cardiopulmonary resuscitation (ECPR) and uncontrolled donation after circulatory determination of death (uDCDD) in refractory cardiac arrest (rCA).

METHODS

Single center, prospective, observational study of selected patients with in-hospital (IHCA) and out-of-hospital (OHCA) rCA occurring in an urban area of ∼1.5 million inhabitants, between October-2016 and May-2018. 65 year old or younger patients without significant bleeding or comorbidities with witnessed nonasystolic cardiac arrests were triaged to ECPR if they had a reversible cause and high quality CPR lasting < 60 min. Otherwise they were considered for uDCDD after a ten minute no touch period using normothermic regional perfusion.

RESULTS

58 patients were included, of which 41 (71%) were OHCA and 18 (31%) had ECPR initiated. Median age was 52 (IQR 45-56) years. Cannulation was successful in 49/58 (84%) cases. Compared to ECPR, patients referred for uDCDD were more frequently OHCA (90 vs. 28%), had bystander CPR (28 vs. 83%) and prolonged low-flow period (40 (35-50) vs. 60 (49-78) min). Survival to hospital discharge with full neurological recovery (cerebral performance category 1) occurred in 6/18 (33%) ECPR patients. uDCDD resulted in transplantation of 44 kidneys.

CONCLUSIONS

An integrated program for rCA consisting of a formal pathway to uDCDD referral in ECPR ineligible patients is feasible. ECPR-referred patients had a reasonable survival with full neurologic recovery. Successful kidney transplantation was achieved with uDCDD.

Principi e indicazioni dell’assistenza circolatoria e respiratoria extracorporea in chirurgia toracica

In origine, l’extracorporeal membrane oxygenation (ECMO) era una tecnica di assistenza respiratoria che utilizzava uno scambiatore gassoso a membrana. Per estensione, l’ECMO è diventata una tecnica respiratoria e cardiopolmonare utilizzata in caso di deficit respiratorio e/o cardiaco nell’attesa della restaurazione della funzione deficitaria o di un eventuale trapianto. Il supporto emodinamico può essere parziale o totale. Gli accessi vascolari possono essere periferici o centrali. Questo tipo di assistenza utilizza il concetto di circolazione extracorporea (CEC) sanguigna che in epoca moderna si è estesa con l’utilizzo di polmoni artificiali a membrana. Il circuito di base è semplice e comprende una pompa, un ossigenatore (che permette al sangue di caricarsi di O₂ e di eliminare CO₂) e delle vie d’accesso (una di drenaggio e una di reinfusione). La sua attuazione è facile, veloce e può essere avviata al letto del malato. Il miglioramento delle attrezzature, una migliore conoscenza delle tecniche e delle indicazioni, e le politiche di salute pubblica hanno reso popolare questa tecnica. Alcuni centri di chirurgia toracica la utilizzano di routine come assistenza alla realizzazione di un intervento terapeutico (soprattutto trapianto) assieme a team di rianimazione per il trattamento della sindrome da distress respiratorio acuto. Nel quadro della malattia polmonare dell’adulto, l’idea principale è quella di sviluppare il concetto di strategia minimalista con l’uso di una CEC adiuvante parziale – più che sostitutiva totale – che permetterebbe il recupero metabolico ad integrum del paziente. Nei prossimi anni, i progressi della tecnologia e dell’ingegneria così come le conoscenze approfondite permetteranno il miglioramento della prognosi dei pazienti colpiti da deficit respiratorio sotto assistenza meccanica.

Improving the Outcomes of Organs Obtained From Controlled Donation After Circulatory Death Donors Using Abdominal Normothermic Regional Perfusion

The use of donation after circulatory death (DCD) has increased significantly during the past decade. However, warm ischemia results in a greater risk for transplantation. Indeed, controlled DCD (cDCD) was associated with inferior outcomes compared with donation after brain death. The use of abdominal normothermic regional perfusion (nRP) to restore blood flow before organ recovery in cDCD has been proposed as better than rapid recovery to reverse the effect of ischemia and improve recipients' outcome. Here, the first Spanish series using abdominal nRP as an in situ conditioning method is reported. A specific methodology to avoid restoring circulation to the brain after death determination is described. Twenty-seven cDCD donors underwent abdominal nRP during at least 60 min. Thirty-seven kidneys, 11 livers, six bilateral lungs, and one pancreas were transplanted. The 1-year death-censored kidney survival was 91%, and delayed graft function rate was 27%. The 1-year liver survival rate was 90.1% with no cases of ischemic cholangiopathy. Transplanted lungs and pancreas exhibited primary function. The use of nRP may represent an advance to increase the number and quality of grafts in cDCD. Poor results in cDCD livers could be reversed with nRP. Concerns about restoring brain circulation after death are easily solved.

Principi e indicazioni dell’assistenza circolatoria e respiratoria extracorporea in chirurgia toracica

In origine, l’extracorporeal membrane oxygenation (ECMO) era una tecnica di assistenza respiratoria che utilizzava uno scambiatore gassoso a membrana. Per estensione, l’ECMO è diventata una tecnica respiratoria e cardiopolmonare utilizzata in caso di deficit respiratorio e/o cardiaco nell’attesa della restaurazione della funzione deficitaria o di un eventuale trapianto. Il supporto emodinamico può essere parziale o totale. Gli accessi vascolari possono essere periferici o centrali. Questo tipo di assistenza utilizza il concetto di circolazione extracorporea (CEC) sanguigna che in epoca moderna si è estesa con l’utilizzo di polmoni artificiali a membrana. Il circuito di base è semplice e comprende una pompa, un ossigenatore (che permette al sangue di caricarsi di O₂ e di eliminare CO₂) e delle vie d’accesso (una di drenaggio e una di reinfusione). La sua attuazione è facile, veloce e può essere avviata al letto del malato. Il miglioramento delle attrezzature, una migliore conoscenza delle tecniche e delle indicazioni, e le politiche di salute pubblica hanno reso popolare questa tecnica. Alcuni centri di chirurgia toracica la utilizzano di routine come assistenza alla realizzazione di un intervento terapeutico (soprattutto trapianto) assieme a team di rianimazione per il trattamento della sindrome da distress respiratorio acuto. Nel quadro della malattia polmonare dell’adulto, l’idea principale è quella di sviluppare il concetto di strategia minimalista con l’uso di una CEC adiuvante parziale – più che sostitutiva totale – che permetterebbe il recupero metabolico ad integrum del paziente. Nei prossimi anni, i progressi della tecnologia e dell’ingegneria così come le conoscenze approfondite permetteranno il miglioramento della prognosi dei pazienti colpiti da deficit respiratorio sotto assistenza meccanica.

Intestinal Conditioning After Cardiac Arrest: The Use of Normothermic Extracorporeal Membrane Oxygenation in the Non-Heart-Beating Animal Model

The effect of normothermic extracorporeal membrane oxygenation (NECMO) on small bowel preservation in a clinically relevant large animal model of expected donation after cardiac death (eDCD) was evaluated. Thirty domestic crossbred donor pigs were divided into five groups. The first group served as the live donation (LD) group, the second group served as the donation after cardiac death (DCD) group, and the remaining were further assigned into three subgroups: E1 group (1 h NECMO support), E3 group (3 h NECMO support), and E5 group (5 h NECMO support). Pathology, electron microscopy, energy metabolism, cell apoptosis, and tight junction (TJ) protein expression level of intestinal mucosa and the level of plasma d-lactic acid were evaluated in normal, cardiac death and at the end of extracorporeal support, respectively. The mean arterial pressure and PaO2 were maintained over 60 and 267 mm Hg during NECMO support, respectively. One hour of extracorporeal support could improve the energy status in intestines of the DCD group. Although the histologic damage and apoptosis of the E1 group had no significant difference with those of the LD and DCD groups (P > 0.05), the levels of intestinal mucosa TJ protein decreased (P < 0.05), and plasma d-lactic acid increased progressively (P < 0.05). With the extension of extracorporeal support, the degree of intestinal mucosa damage and intestinal permeability gradually increased, as well as the content of adenosine triphosphate in intestinal mucosa. The normothermic extracorporeal support for 1 h in DCD is beneficial for improving the energy status and viability of the bowel. However, the integrity of intestinal mucosa was destroyed gradually as extracorporeal support time went by. And the activation of intestinal epithelial apoptosis and hyperoxia might be the factors that lead to intestinal mucosa injury.

The Use of Extracorporeal Circulation in Suspected Brain Dead Organ Donors with Cardiopulmonary Collapse

Donor shortage is a major limitation in organ transplantation. Several studies have reported that extracorporeal membrane oxygenation (ECMO)-assisted organ donation can be successfully completed without inducing warm ischemia in patients with brain death. The present report described clinical experience of three patients (23-yr old man, 32-yr old man, and 41-yr old woman) who underwent ECMO for the evaluation of brain death and organ donation. They donated six kidneys, three livers, and one both lungs without warm ischemia by ECMO. Six kidney recipients successfully recovered normal status without hemodialysis and two liver recipients survived with normal liver functions, but one liver recipient and one lung recipient died 3 and 15 days after transplantation. Our report strongly encourages ECMO-assisted organ donation from brain death patients with refractory cardiopulmonary collapse to achieve improved organ transplantation.

Recommendations for donation after circulatory death kidney transplantation in Europe

Donation after circulatory death (DCD) donors provides an invaluable source for kidneys for transplantation. Over the last decade, we have observed a substantial increase in the number of DCD kidneys, particularly within Europe. We provide an overview of risk factors associated with DCD kidney function and survival and formulate recommendations from the sixth international conference on organ donation in Paris, for best-practice guidelines. A systematic review of the literature was performed using Ovid Medline, Embase and Cochrane databases. Topics are discussed, including donor selection, organ procurement, organ preservation, recipient selection and transplant management.

Molecular pathways in protecting the liver from ischaemia/reperfusion injury: a 2015 update

Ischaemia/reperfusion injury is an important cause of liver damage during surgical procedures such as hepatic resection and liver transplantation, and represents the main cause of graft dysfunction post-transplantation. Molecular processes occurring during hepatic ischaemia/reperfusion are diverse, and continuously include new and complex mechanisms. The present review aims to summarize the newest concepts and hypotheses regarding the pathophysiology of liver ischaemia/reperfusion, making clear distinction between situations of cold and warm ischaemia. Moreover, the most updated therapeutic strategies including pharmacological, genetic and surgical interventions, as well as some of the scientific controversies in the field are described.

Machine perfusion in liver transplantation as a tool to prevent non-anastomotic biliary strictures: Rationale, current evidence and future directions

The high incidence of non-anastomotic biliary strictures (NAS) after transplantation of livers from extended criteria donors is currently a major barrier to widespread use of these organs. This review provides an update on the most recent advances in the understanding of the etiology of NAS. These new insights give reason to believe that machine perfusion can reduce the incidence of NAS after transplantation by providing more protective effects on the biliary tree during preservation of the donor liver. An overview is presented regarding the different endpoints that have been used for assessment of biliary injury and function before and after transplantation, emphasizing on methods used during machine perfusion. The wide spectrum of different approaches to machine perfusion is discussed, including the many different combinations of techniques, temperatures and perfusates at varying time points. In addition, the current understanding of the effect of machine perfusion in relation to biliary injury is reviewed. Finally, we explore directions for future research such as the application of (pharmacological) strategies during machine perfusion to further improve preservation. We stress the great potential of machine perfusion to possibly expand the donor pool by reducing the incidence of NAS in extended criteria organs.

[Veno-arterial extracorporeal membrane oxygenation. Indications, limitations and practical implementation]

Due to the technical advances in pumps, oxygenators and cannulas, veno-arterial extracorporeal membrane oxygenation (va-ECMO) or extracorporeal life support (ECLS) has been widely used in emergency medicine and intensive care medicine for several years. An accepted indication is peri-interventional cardiac failure in cardiac surgery (postcardiotomy low cardiac output syndrome). Furthermore, especially the use of va-ECMO for other indications in critical care medicine, such as in patients with severe sepsis with septic cardiomyopathy or in cardiopulmonary resuscitation has tremendously increased. The basic indications for va-ECMO are therapy refractory cardiac or cardiopulmonary failure. The fundamental purpose of va-ECMO is bridging the function of the lungs and/or the heart. Consequently, this support system does not represent a causal therapy by itself; however, it provides enough time for the affected organ to recover (bridge to recovery) or for the decision for a long-lasting organ substitution by a ventricular assist device or by transplantation (bridge to decision). Although the outcome for bridged patients seems to be favorable, it should not be forgotten that the support system represents an invasive procedure with potentially far-reaching complications. Therefore, the initiation of these systems needs a professional and experienced (interdisciplinary) team, sufficient resources and an individual approach balancing the risks and benefits. This review gives an overview of the indications, complications and contraindications for va-ECMO. It discusses its advantages in organ transplantation and transport of critically ill patients. The reader will learn the differences between peripheral and central cannulation and how to monitor and manage va-ECMO.

First experience of liver transplantation with type 2 donation after cardiac death in France

Organ donation after unexpected cardiac death [type 2 donation after cardiac death (DCD)] is currently authorized in France and has been since 2006. Following the Spanish experience, a national protocol was established to perform liver transplantation (LT) with type 2 DCD donors. After the declaration of death, abdominal normothermic oxygenated recirculation was used to perfuse and oxygenate the abdominal organs until harvesting and cold storage. Such grafts were proposed to consenting patients < 65 years old with liver cancer and without any hepatic insufficiency. Between 2010 and 2013, 13 LTs were performed in 3 French centers. Six patients had a rapid and uneventful postoperative recovery. However, primary nonfunction occurred in 3 patients, with each requiring urgent retransplantation, and 4 early allograft dysfunctions were observed. One patient developed a nonanastomotic biliary stricture after 3 months, whereas 8 patients showed no sign of ischemic cholangiopathy at their 1-year follow-up. In comparison with a control group of patients receiving grafts from brain-dead donors (n = 41), donor age and cold ischemia time were significantly lower in the type 2 DCD group. Time spent on the national organ wait list tended to be shorter in the type 2 DCD group: 7.5 months [interquartile range (IQR), 4.0-11.0 months] versus 12.0 months (IQR, 6.8-16.7 months; P = 0.08. The 1-year patient survival rates were similar (85% in the type 2 DCD group versus 93% in the control group), but the 1-year graft survival rate was significantly lower in the type 2 DCD group (69% versus 93%; P = 0.03). In conclusion, to treat borderline hepatocellular carcinoma, LT with type 2 DCD donors is possible as long as strict donor selection is observed.

French survey of the first three-years of liver transplantation activity from uncontrolled donors deceased after cardiac death

OBJECTIVE

To assess the first three years of French activity related to liver transplantation from uncontrolled donation after cardiac death (uDCD).

STUDY DESIGN

Prospective and observational study in the three active centres authorized by the French Biomedicine Agency.

PATIENTS AND METHODS

All patients deceased between 2010 and 2012 after an uncontrolled cardiac arrest admitted to one of three centres (Pitié-Salpêtrière, Saint-Louis or Bicêtre hospitals, AP-HP, Paris, France) and potentially eligible for liver recovery were included. Abdominal normothermic oxygenated recirculation (ANOR) was used for graft preservation.

RESULTS

One hundred twenty-six potential uDCD donors were identified as eligible for liver recovery after hospital admission. The main causes of organ recovery failure were technical failure related to ANOR (29 patients, 23%), refusal of consent (39 patients, 31% of potential uDCD donors and 40% of asked relatives) and abnormal hepatic transaminases up to 200 UI.L(-1) during ANOR (24 patients, 19%). Finally, 11 livers were transplanted. Process efficiency was 9% [95% CI: 4-15%]. One-year recipient survival was 82%, [95% CI: 48-98%] and one-year graft survival was 64% [95% CI: 31-89%].

CONCLUSION

Liver transplantation from uDCD donors is achievable in France, despite low process efficiency.

Short-term result of renal transplantation using extracorporeal membrane oxygenation-supported brain-dead donors

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is now widely used to maintain hemodynamic stability after traumatic events among medical centers. It remains unclear whether renal transplantation using ECMO-supported donors carries poorer outcomes.

METHODS

From February 2010 to March 2013, we performed 9 renal transplantations (6 females and 3 males) from 5 ECMO-supported donors. Demographic data and clinical outcomes were retrospectively analyzed through medical chart review.

RESULTS

The mean follow-up period was 15 ± 9 months (range: 8-37). Eight of the 9 grafts remained functioning within the follow-up period. One (11.1%) graft loss was noted after repeated acute rejection. Acute rejection occurred in 3/9 (33%) of cases. Delayed graft function was also observed in 3/9 (33%) of cases.

CONCLUSION

Renal transplantation using ECMO-supported brain-dead donors was not associated with an unacceptably high rate of graft loss in this short-term follow-up. It might be an alternative way to expand donor pools.

Retrieval of the pancreas allograft for whole-organ transplantation

Proper pancreas retrieval during multi-organ recovery is one of the cornerstones of technically successful whole-organ pancreas transplantation. With evolving surgical approaches for organ retrieval and implantation, it has become standard to procure the pancreas in conjunction with other abdominal organs without compromising either vasculature, graft quality, or transplant outcomes. This review summarizes the major steps required for proper whole-organ retrieval of the pancreas allograft with suggestions and tips whenever alternative approaches are available.

Normothermic regional perfusion for donation after circulatory death without prior heparinization

BACKGROUND

Over 40% of deceased donors in the UK donate after circulatory death (DCD). Normothermic regional perfusion has been reported to improve outcomes in such donors in Europe and the United States. Unlike the United States, legal and professional requirements in the UK prevent cannulation and heparinization before verification of death, which must be a minimum of 5 min after circulatory arrest. We developed a novel protocol for in situ normothermic regional perfusion (NRP) which complied with these requirements.

METHODS

NRP was achieved by cannulating the aorta and vena cava after death. Donor blood was then warmed and oxygenated using a bespoke extracorporeal membrane oxygenator circuit before return to the donor. A shunt was incorporated into the extracorporeal circuit to permit heparin mixing before oxygenation and warming was commenced to prevent thrombosis of the oxygenator. Normothermic perfusion was continued for 2 hr before in situ cold perfusion with preservation fluid. All organs were subject to static cold storage after recovery.

RESULTS

Eight controlled DCD donors underwent NRP from which 3 livers, 2 pancreases, and 14 kidneys were transplanted. Four livers were not used because of biochemical evidence of hepatocellular damage and one because of cirrhosis. Two kidneys were lost from venous thrombosis before function returned and two developed delayed graft function; all transplanted livers and pancreases had primary function.

CONCLUSIONS

Cannulation and heparinization after circulatory arrest does not prevent successful normothermic regional perfusion. The technique permits evaluation of donor organs before implantation and may improve short-term outcomes.

Hypothermic or normothermic abdominal regional perfusion in high-risk donors with extended warm ischemia times: impact on outcomes?

Donation after circulatory determination of death (DCD) has the potential to increase the applicability of transplantation as a treatment for end-stage organ disease; its use is limited, however, by the warm ischemic damage suffered by potential grafts. Abdominal regional perfusion (ARP) has been employed in this setting to not only curtail the deleterious effects of cardiac arrest by re-establishing oxygenated flow but also test and even improve the viability of the kidneys and liver prior to transplantation. In the present review article, we discuss experimental and clinical studies that have been published to date on the use of ARP in DCD, differentiating between its application under hypothermic and normothermic conditions. In addition to describing results that have been achieved thus far, we describe the major obstacles limiting the broader implementation of ARP in this context as well as potential means for improving the effectiveness of this modality in the future.

Development of a preclinical model of donation after circulatory determination of death for translational application

Background

Extracorporeal membranous oxygenation is proposed for abdominal organ procurement from donation after circulatory determination of death (DCD). In France, the national Agency of Biomedicine supervises the procurement of kidneys from DCD, specifying the durations of tolerated warm and cold ischemia. However, no study has determined the optimal conditions of this technique. The aim of this work was to develop a preclinical model of DCD using abdominal normothermic oxygenated recirculation (ANOR). In short, our objectives are to characterize the mechanisms involved during ANOR and its impact on abdominal organs.

Methods

We used Large White pigs weighing between 45 and 55 kg. After 30 minutes of potassium-induced cardiac arrest, the descending thoracic aorta was clamped and ANOR set up between the inferior vena cava and the abdominal aorta for 4 hours. Hemodynamic, respiratory and biochemical parameters were collected. Blood gasometry and biochemistry analysis were performed during the ANOR procedure.

Results

Six ANOR procedures were performed. The surgical procedure is described and intraoperative parameters and biological data are presented. Pump flow rates were between 2.5 and 3 l/min. Hemodynamic, respiratory, and biochemical objectives were achieved under reproducible conditions. Interestingly, animals remained hemodynamically stable following the targeted protocol. Arterial pH was controlled, and natremia and renal function remained stable 4 hours after the procedure was started. Decreased hemoglobin and serum proteins levels, concomitant with increased lactate dehydrogenase activity, were observed as a consequence of the surgery. The serum potassium level was increased, owing to the extracorporeal circulation circuit.

Conclusions

Our ANOR model is the closest to clinical conditions reported in the literature and will allow the study of the systemic and abdominal organ impact of this technique. The translational relevance of the pig will permit the determination of new biomarkers and protocols to improve DCD donor management.

Outcome of organs procured from donors on extracorporeal membrane oxygenation support: an analysis of kidney and liver allograft data

INTRODUCTION

Extracorporeal membrane oxygenation has become rescue therapy for adults with overwhelming cardiac and/or respiratory failure. Not all patients are saved, creating a new cohort of potential organ donors. This study examines the outcomes of liver and kidney allografts procured from donors on extracorporeal membrane oxygenation (ECMO).

METHODS

A retrospective review was conducted through the local organ procurement organization. Donors on ECMO prior to notification were classified into donation after brain death (DBD) and donation after cardiac death (DCD). We compared short-term outcome data against published standards.

RESULTS

Between 1995 and 2012, 97 organs were procured from 41 donors supported on ECMO. There were 68 kidneys donated, 51 were transplanted and 17 discarded. Excluding extended criteria donors, 29 DBD and 13 DCD kidneys were transplanted from donors supported on ECMO. Delayed graft function occurred in 34% of DBD kidneys and 38% of DCD kidneys. Kidney allograft survival at one yr was 93%. Twenty-four livers were procured, nine discarded, and 15 transplanted. Ninety-three percent of liver transplant recipients were alive with graft function at one yr.

CONCLUSIONS

Donation after brain death kidneys procured from donors on ECMO perform similarly to non-ECMO organs with regard to delayed graft function (DGF), one-yr graft survival and function. Livers from ECMO donors have a higher discard rate than non-ECMO donors, but function similarly at six months and one yr.