Results of Clinical Lung Transplant From Uncontrolled Non-Heart-Beating Donors

Uncontrolled Donation after Circulatory Death Only Lung Program: An Urgent Opportunity

Uncontrolled donation after circulatory death (uDCD) represents a potential source of lungs, and since Steen's 2001 landmark case in Sweden, lungs have been recovered from uDCD donors and transplanted to patients in other European countries (France, the Netherlands, Spain and Italy) with promising results. Disparities still exist among European countries and among regions in Italy due to logistical and organizational factors. The present manuscript focuses on the clinical experiences pertaining to uDCD lungs in North America and European countries and on different lung maintenance methods. Existing experiences (and protocols) are not uniform, especially with respect to the type of lung maintenance, the definition of warm ischemic time (WIT) and, finally, the use of ex vivo perfusion (available in the last several years in most centers). In situ lung cooling may be superior to protective ventilation, but this process may be difficult to perform in the uDCD setting and is also time-consuming. On the other hand, the "protective ventilation technique" is simpler and feasible in every hospital. It may lead to a broader use of uDCD lung donors. To date, the results of lung transplants performed after protective ventilation as a preservation technique are scarce but promising. All the protocols comprise, among the inclusion criteria, a witnessed cardiac arrest. The detectable differences included preservation time (240 vs. 180 min) and donor age (<55 years in Spanish protocols and <65 years in Toronto protocols). Overall, independently of the differences in protocols, lungs from uDCD donors show promising results, and the possibility of optimizing ex vivo lung perfusion may broaden the use of these organs.

Expanding the Lung Donor Pool: Donation After Circulatory Death, Ex-Vivo Lung Perfusion and Hepatitis C Donors

"Organ shortage remains a limiting factor in lung transplantation. Traditionally, donation after brain death has been the main source of lungs used for transplantation; however, to meet the demand of patients requiring lung transplantation it is crucial to find innovative methods for organ donation. The implementation of extended donors, lung donation after cardiac death (DCD), the use of ex-vivo lung perfusion (EVLP) systems, and more recently the acceptance of hepatitis C donors have started to close the gap between organ donors and recipients in need of lung transplantation. This article focuses on the expansion of donor lungs for transplantation after DCD, the use of EVLP in evaluating extended criteria lungs, and the use of lung grafts from donors with hepatitis C."

Donation after Circulatory Death in Lung Transplantation

The shortage of donor lungs has become a serious obstacle to implementing lung transplantation (LTx). Donation after circulatory death (DCD) donors are among the several donor pools utilized to overcome the problem posed by the shortage of donation after brain death (DBD) donors. The active use of DCD donors is expected to significantly reduce mortality on the waiting list for LTx, as LTx from DCD donors has comparable outcomes to LTx from DBD donors. Further studies on efforts to shorten the warm ischemic time and use uncontrolled DCD are required.

Epigenetic Alterations and Inflammation as Emerging Use for the Advancement of Treatment in Non-Small Cell Lung Cancer

Lung cancer remains one of the most common malignancies in the world. Nowadays, the most common lung cancer is non-small cell lung cancer (NSCLC), namely, adenocarcinoma, squamous cell carcinoma, and large cell lung carcinoma. Epigenetic alterations that refer to DNA methylation, histone modifications, and noncoding RNA expression, are now suggested to drive the genesis and development of NSCLC. Additionally, inflammation-related tumorigenesis also plays a vital role in cancer research and efforts have been attempted to reverse such condition. During the occurrence and development of inflammatory diseases, the immune component of inflammation may cause epigenetic changes, but it is not always certain whether the immune component itself or the stimulated host cells cause epigenetic changes. Moreover, the links between epigenetic alterations and cancer-related inflammation and their influences on the human cancer are not clear so far. Therefore, the connection between epigenetic drivers, inflammation, and NSCLC will be summarized. Investigation on such topic is most likely to shed light on the molecular and immunological mechanisms of epigenetic and inflammatory factors and promote the application of epigenetics in the innovative diagnostic and therapeutic strategies for NSCLC.

Donation after circulatory death donors in lung transplantation

Transplantation of any organ into a recipient requires a donor. Lung transplant has a long history of an inadequate number of suitable donors to meet demand, leading to deaths on the waiting list annually since national data was collected, and strict listing criteria. Before the Uniform Determination of Death Act (UDDA), passed in 1980, legally defined brain death in the U.S., all donors for lung transplant came from sudden death victims [uncontrolled Donation after Circulatory Death donors (uDCDs)] in the recipient’s hospital emergency department. After passage of the UDDA, uDCDs were abandoned to Donation after Brain Death donors (DBDs)—perhaps prematurely. Compared to livers and kidneys, many DBDs have lungs that are unsuitable for transplant, due to aspiration pneumonia, neurogenic pulmonary edema, trauma, and the effects of brain death on lung function. Another group of donors has become available—patients with a devastating irrecoverable brain injury that do not meet criteria for brain death. If a decision is made by next-of-kin (NOK) to withdraw life support and allow death to occur by asphyxiation, with NOK consent, these individuals can have organs recovered if death occurs relatively quickly after cessation of mechanical ventilation and maintenance of their airway. These are known as controlled Donation after Circulatory Death donors (cDCDs). For a variety of reasons, in the U.S., lungs are recovered from cDCDs at a much lower rate than kidneys and livers. Ex-vivo lung perfusion (EVLP) in the last decade has had a modest impact on increasing the number of lungs for transplant from DBDs, but may have had a larger impact on lungs from cDCDs, and may be indispensable for safe transplantation of lungs from uDCDs. In the next decade, DCDs may have a substantial impact on the number of lung transplants performed in the U.S. and around the world.

New models for donor-recipient matching in lung transplantations

Objective

One of the main problems of lung transplantation is the shortage of organs as well as reduced survival rates. In the absence of an international standardized model for lung donor-recipient allocation, we set out to develop such a model based on the characteristics of past experiences with lung donors and recipients with the aim of improving the outcomes of the entire transplantation process.

Methods

This was a retrospective analysis of 404 lung transplants carried out at the Reina Sofía University Hospital (Córdoba, Spain) over 23 years. We analyzed various clinical variables obtained via our experience of clinical practice in the donation and transplantation process. These were used to create various classification models, including classical statistical methods and also incorporating newer machine-learning approaches.

Results

The proposed model represents a powerful tool for donor-recipient matching, which in this current work, exceeded the capacity of classical statistical methods. The variables that predicted an increase in the probability of survival were: higher pre-transplant and post-transplant functional vital capacity (FVC), lower pre-transplant carbon dioxide (PCO2) pressure, lower donor mechanical ventilation, and shorter ischemia time. The variables that negatively influenced transplant survival were low forced expiratory volume in the first second (FEV1) pre-transplant, lower arterial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2) ratio, bilobar transplant, elderly recipient and donor, donor-recipient graft disproportion requiring a surgical reduction (Tailor), type of combined transplant, need for cardiopulmonary bypass during the surgery, death of the donor due to head trauma, hospitalization status before surgery, and female and male recipient donor sex.

Conclusions

These results show the difficulty of the problem which required the introduction of other variables into the analysis. The combination of classical statistical methods and machine learning can support decision-making about the compatibility between donors and recipients. This helps to facilitate reliable prediction and to optimize the grafts for transplantation, thereby improving the transplanted patient survival rate.

Donation after circulatory death (DCD)-lung procurement

The number of lungs available for lung transplantation is far lower than the number of patients awaiting them. Consequently, there is a significant attrition rate while awaiting transplantation. Lung procurement rates are lower than those of other solid organs. Lungs are procured from only 15–20% of donors compared with 30% of decreased donors for hearts. The reason for this low retrieval rate is related to a number of factors. Brain death is associated with neurogenic pulmonary edema. Additionally, injury to the lung itself may occur before or after brain death. Aspiration of gastric contents, pneumonia, previous thoracic trauma, ventilator-associated injury, atelectasis, and pulmonary thrombosis/embolism may all contribute to lung injury before consideration for harvest. Donation after circulatory death (DCD) is one category of nontraditional organ donation now being performed in increasing numbers as a way to increase the number of lungs available for transplantation. In some studies, estimates show that utilization of DCD lung procurement could increase the number of lungs available by up to 50%.

Uncontrolled Donation After Circulatory Death: A Unique Opportunity

Uncontrolled donation after circulatory death (uDCD) refers to donation from persons who die following an unexpected and unsuccessfully resuscitated cardiac arrest. Despite the large potential for uDCD, programs of this kind only exist in a reduced number of countries with a limited activity. Barriers to uDCD are of a logistical and ethical-legal nature, as well as arising from the lack of confidence in the results of transplants from uDCD donors. The procedure needs to be designed to reduce and limit the impact of the prolonged warm ischemia inherent to the uDCD process, and to deal with the ethical issues that this practice poses: termination of advanced cardiopulmonary resuscitation, extension of advanced cardiopulmonary resuscitation beyond futility for organ preservation, moment to approach families to discuss donation opportunities, criteria for the determination of death, or the use of normothermic regional perfusion for the in situ preservation of organs. Although the incidence of primary nonfunction and delayed graft function is higher with organs obtained from uDCD donors, overall patient and graft survival is acceptable in kidney, liver, and lung transplantation, with a proper selection and management of both donors and recipients. Normothermic regional perfusion has shown to be critical to achieve optimal outcomes in uDCD kidney and liver transplantation. However, the role of ex situ preservation with machine perfusion is still to be elucidated. uDCD is a unique opportunity to improve patient access to transplantation therapies and to offer more patients the chance to donate organs after death, if this is consistent with their wishes and values.

HSP90 Inhibitor Improves Lung Protection in Porcine Model of Donation After Circulatory Arrest

BACKGROUND

Ischemia-reperfusion associated with prolonged warm ischemia during donation after circulatory death (DCD) induces acute lung injury. The objective of this study was to combine ex vivo lung perfusion (EVLP) and a heat shock protein-90 inhibitor (HSP90i) to recondition DCD organs and prevent primary graft dysfunction.

METHODS

Pigs (55 to 65 kg) were anesthetized, ventilated, and hemodynamically monitored. Cardiac arrest was induced with potassium chloride, and animals were left nonventilated for 2 hours. Lungs were procured and perfused in an EVLP platform for 4 hours by using a cellular perfusate. In the study group, the perfusate contained HSP90i and its transport vehicle (n = 4). In the control group, the perfusate contained only the transport vehicle (n = 4). Gas exchange, airway pressures, and compliance were measured. Pulmonary edema was assessed by bronchoscopy and weight measurement. Lung biopsy samples were obtained for histologic analyses and protein expression measurements.

RESULTS

The use of HSP90i reduced lung weight gain to 8.4 ± 3.4% vs 26.6 ± 6.2% in the control group (P < .05). There was reduced edema formation. The ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen at the end of EVLP was 423 ± 65 in the study group vs 339 ± 25 mm Hg in the control group, but this difference was not statistically significant. Lactate metabolism, pulmonary vascular resistance, and pulmonary arterial pressure improved during EVLP with the use of the HSP90i.

CONCLUSIONS

The use of HSP90i with EVLP improves the lung reconditioning process. Further research is required to confirm whether these findings translate to benefit once transplanted and observed in vivo. Successful pharmacologic inhibitors may expand the donor pool in the context of DCD donors.

Progress of Clinical Application for Ex Vivo Lung Perfusion (EVLP) in Lung Transplantation

In recent years, medical advances make lung transplantation become a standard treatment for terminal lung diseases (such as emphysema, pulmonary fibrosis, pulmonary cystic fibrosis, and pulmonary arterial hypertension) that cannot be cured by drugs or surgery (Lund et al., J Heart Lung Transplant 34:1244, 2015). However, the current number of donor lungs that meet the transplant criteria is no longer sufficient for transplanting, causing some patients to die while waiting for a suitable lung. Current methods for improving the situation of shortage of lung transplant donors include the use of donation after cardiac death (DCD) donors, smoker donors, and Ex Vivo Lung Perfusion (EVLP). Among them, EVLP is a technique for extending lung preservation time and repairing lung injury in the field of lung transplantation. By continuously assessing and improving the function of marginal donor lungs, EVLP increases the number of lungs that meet the transplant criteria and, to some extent, alleviates the current situation of shortage of donor lungs. This chapter reviews the clinical application and research progress of EVLP in the field of lung transplantation.

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.

The Future of Lung Transplantation

The field of lung transplant has made significant advances over the last several decades. Despite these advances, morbidity and mortality remain high when compared with other solid organ transplants. As the field moves forward, the speed by which progress can be made will in part be determined by our ability to overcome several stumbling blocks, including donor shortage, proper selection of candidates, primary graft dysfunction, and chronic lung allograft dysfunction. The advances and developments surrounding these factors will have a significant impact on shaping the field within the coming years. In this review, we look at the current climate (ripe for expanding the donor pool), new technology (ex vivo lung perfusion and bioengineered lungs), cutting-edge innovation (novel biomarkers and new ways to treat infected donors), and evidence-based medicine to discuss current trends and predict future developments for what we hope is a bright future for the field of lung transplantation.

A new way of monitoring mechanical ventilation by measurement of particle flow from the airways using Pexa method in vivo and during ex vivo lung perfusion in DCD lung transplantation

BACKGROUND

Different mechanical ventilation settings are known to affect lung preservation for lung transplantation. Measurement of particle flow in exhaled air may allow online assessment of the impact of ventilation before changes in the tissue can be observed. We hypothesized that by analyzing the particle flow, we could understand the impact of different ventilation parameters.

METHODS

Particle flow was monitored in vivo, post mortem, and in ex vivo lung perfusion (EVLP) in six porcines with the Pexa (particles in exhaled air) instrument. Volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) were used to compare small versus large tidal volumes. The surfactant lipids dipalmitoylphosphatidylcholine (DPPC) and phosphatidylcholine (PC) were quantified by mass spectrometry.

RESULTS

In vivo the particle mass in VCV¹ was significantly lower than in VCV² (p = 0.0186), and the particle mass was significantly higher in PCV¹ than in VCV¹ (p = 0.0322). In EVLP, the particle mass in VCV¹ was significantly higher than in PCV¹ (p = 0.0371), and the particle mass was significantly higher in PCV² than in PCV¹ (p = 0.0127). DPPC was significantly higher in EVLP than in vivo.

CONCLUSIONS

Here, we introduce a new method for measuring particle flow during mechanical ventilation and confirm that these particles can be collected and analyzed. VCV resulted in a lower particle flow in vivo but not in EVLP. In all settings, large tidal volumes resulted in increased particle flow. We found that DPPC was significantly increased comparing in vivo with EVLP. This technology may be useful for developing strategies to preserve the lung and has a high potential to detect biomarkers.

The impact of alteplase on pulmonary graft function in donation after circulatory death - An experimental study

Objective

Lung transplantation is hampered by the lack of organs resulting in deaths on the waiting list. The usage of donation after circulatory death (DCD) lungs would dramatically increase donor availability. The most optimal organ preservation method, and the need for antithrombotic and fibrinolytic treatment to prevent thrombosis in the donor lungs is currently on debate. The present study investigated, in a simulated clinical DCD situation, whether the addition of alteplase in the flush-perfusion solution at the time of pulmonary graft harvesting could prevent thrombosis in the donor lung and thereby improve pulmonary graft function.

Methods

Twelve Swedish domestic pigs were randomized into two groups. All animals underwent ventricular fibrillation and were then left untouched for 1 h after declaration of death. None of the animals received heparin. The lungs were then harvested and flush-perfused with Perfadex^® solution and the organs were then stored at 8 °C for 4 h. In one group alteplase was added to the Perfadex^® solution (donation after cardiac death with alteplase (DCD-A)) and in the other, it was not (DCD). Lung function was evaluated, using ex vivo lung perfusion (EVLP), with blood gases at different oxygen levels, pulmonary vascular resistance (PVR), lung weight, and macroscopic appearance.

Results

During EVLP, there were no significant differences between groups in PaO₂ at any investigated FiO₂ level (1.0, 0.5, or 0.21). At FiO₂ 1.0, the PaO₂ in the DCD and DCD-A was 51.7 ± 2.05 kPa and 60.3 ± 3.67 kPa, respectively (p = 0.1320). There were no significant differences between groups PVR levels, in the DCD (372 ± 31 dyne x s/cm⁵) and in the DCD-A (297 ± 37 dyne x s/cm⁵) groups (p = 0.1720). There was no significant difference between groups in macroscopic appearance.

Conclusions

All the lungs showed excellent blood gases after EVLP, and they all meet the criteria's for clinical lung transplantation. The use of alteplase did not seem to have any obvious benefit to the donor lungs in a DCD situation. The donor lungs treated with alteplas showed slightly better blood gases and slightly lower PVR compared to the group without alteplas, however the difference was not significant. DCD appears to be a safe and effective method to expand the donor pool.

Donors after cardiocirculatory death and lung transplantation

The number of patients actively awaiting lung transplantation (LTx) is more than the number of suitable donor lungs. The percentage of lung retrieval rate is lower when compared to other solid organs. The use of lungs from donation after cardiocirculatory death (DCD) donors is one of the options to avoid organ shortage in LTx. After extensive experimental research, clinical application of DCD donation is becoming wider. The results from most of the centers show at least equal survival rate compared to donors from brain death. This review paper will summarize experimental background and clinical experience from DCD donors.

Lung Donation After Controlled Circulatory Determination of Death: A Review of Current Practices and Outcomes

BACKGROUND

Since the first reported series in 1995, transplantation of lungs recovered through donation after circulatory determination of death (DCDD) has steadily increased. In some European and Australian centers, controlled DCDD accounts for 15% to 30% of all transplanted lungs. Several transplant centers have reported early and midterm outcomes similar to those associated with the use of donors after brain death. Despite these encouraging reports, less than 2% of all lung transplants in the United States are performed using donors after circulatory determination of death.

METHODS

An electronic search from January 1990 to January 2014 was performed to identify series reporting lung transplant outcomes using controlled DCDD. Data from these publications were analyzed in terms of donor characteristics, donation after circulatory determination of death protocols, recipients' characteristics, and early and midterm outcomes.

RESULTS

Two hundred twenty-two DCDDs were transplanted into 225 recipients. The rate of primary graft dysfunction grade 3 ranged from 3% to 36%. The need for extracorporeal membrane oxygenation support after transplantation ranged from 0% to 18%. The average intensive care unit stay ranged from 4 to 8.5 days and the average hospital stay ranged from 14 to 35 days. Thirty-day mortality ranged from 0% to 11% and 1-year survival from 88% to 100%.

CONCLUSION

Under clinical protocols developed and strictly applied by several experienced lung transplant programs, lungs from controlled DCDD have produced outcomes very similar to those observed with brain death donors.

Ex Vivo Perfusion With Adenosine A2A Receptor Agonist Enhances Rehabilitation of Murine Donor Lungs After Circulatory Death

BACKGROUND

Ex vivo lung perfusion (EVLP) enables assessment and rehabilitation of marginal donor lungs before transplantation. We previously demonstrated that adenosine A2A receptor (A2AR) agonism attenuates lung ischemia-reperfusion injury. The current study utilizes a novel murine EVLP model to test the hypothesis that A2AR agonist enhances EVLP-mediated rehabilitation of donation after circulatory death (DCD) lungs.

METHODS

Mice underwent euthanasia and 60 minutes warm ischemia, and lungs were flushed with Perfadex and underwent cold static preservation (CSP, 60 minutes). Three groups were studied: no EVLP (CSP), EVLP with Steen solution for 60 minutes (EVLP), and EVLP with Steen solution supplemented with ATL1223, a selective A2AR agonist (EVLP + ATL1223). Lung function, wet/dry weight, cytokines and neutrophil numbers were measured. Microarrays were performed using the Affymetrix GeneChip Mouse Genome 430A 2.0 Array.

RESULTS

Ex vivo lung perfusion significantly improved lung function versus CSP, which was further, significantly improved by EVLP + ATL1223. Lung edema, cytokines, and neutrophil counts were reduced after EVLP and further, significantly reduced after EVLP + ATL1223. Gene array analysis revealed differential expression of 1594 genes after EVLP, which comprise canonical pathways involved in inflammation and innate immunity including IL-1, IL-8, IL-6, and IL-17 signaling. Several pathways were uniquely regulated by EVLP + ATL1223 including the downregulation of genes involved in IL-1 signaling, such as ADCY9, ECSIT, IRAK1, MAPK12, and TOLLIP.

CONCLUSIONS

Ex vivo lung perfusion modulates proinflammatory genes and reduces pulmonary dysfunction, edema, and inflammation in DCD lungs, which are further reduced by A2AR agonism. This murine EVLP model provides a novel platform to study rehabilitative mechanisms of DCD lungs.

Uncontrolled donation after circulatory death: European practices and recommendations for the development and optimization of an effective programme

The shortage of organs remains one of the biggest challenges in transplantation. To address this, we are increasingly turning to donation after circulatory death (DCD) donors and now in some countries to uncontrolled DCD donors. We consolidate the knowledge on uncontrolled DCD in Europe and provide recommendations and guidance for the development and optimization of effective uncontrolled DCD programmes.

Expanding the lung donor pool: advancements and emerging pathways. Curr Opin Organ Transplant. 2015;20:498-505. [PMID: 26262464 DOI: 10.1097/mot.0000000000000233]

PURPOSE OF REVIEW

The number of patients listed for lung transplantation largely exceeds the number of available transplantable organs because of a shortage of organ donors and a low utilization rate of lungs from those donors who are available. In recent years, novel strategies have been developed to increase the donor lung pool: improved donor management, the use of lungs from donations after cardiac death (DCD), the use of lobar lung living-donors (LLLD) and the use of ex-vivo lung perfusion (EVLP) to assess and repair injured donor lungs.

RECENT FINDINGS

An adapted donor management strategy could expand the donor pool up to 20%. DCD lung transplant is an increasing part of the donor pool expansion. Outcomes after controlled DCD seem to be similar to donation after brain death. LLLD transplantation has excellent results for small and critically ill patients. EVLP treatment allows for a significant increase in the rate of suitable lungs and represents an optimal platform for lung reconditioning and specific lung therapies.

SUMMARY

A significant increase in the number of available lungs for transplantation is expected in the future because of the wider use of lungs from controlled or uncontrolled DCD and LLLD lungs, and with organ-specific EVLP treatment strategies.

Ex vivo lung perfusion

Lung transplantation is an established life-saving therapy for patients with end-stage lung disease. Unfortunately, greater success in lung transplantation is hindered by a shortage of lung donors and the relatively poor early-, mid-, and long-term outcomes associated with severe primary graft dysfunction. Ex vivo lung perfusion has emerged as a modern preservation technique that allows for a more accurate lung assessment and improvement in lung quality. This review outlines the: (i) rationale behind the method; (ii) techniques and protocols; (iii) Toronto ex vivo lung perfusion method; (iv) devices available; and (v) clinical experience worldwide. We also highlight the potential of ex vivo lung perfusion in leading a new era of lung preservation.

Lungs exposed to 1 hour warm ischemia without heparin before harvesting might be suitable candidates for transplantation

Background

The limiting factor for lung transplantation is the lack of donor organs. The usage of lungs from donation after cardiac death (DCD) would dramatically increase donor availability. In the present paper we wanted to investigate lungs exposed to 1 h of warm ischemia without heparin followed by flush-perfusion and cold storage compared to lungs harvested from heart beating donors (HBD) using standard harvesting technique.

Methods

Twelve Swedish domestic pigs were randomized into two groups. Six pigs (DCD group) underwent ventricular fibrillation and were then left untouched for 1 h after declaration of death. They did not receive heparin. The lungs were then harvested and flush-perfused with Perfadex® solution and the organs were stored at 8 °C for 4 h. Six pigs (HBD group) received heparin and the lungs were harvested and flush-perfused with Perfadex® solution and the organs were stored at 8 °C for 4 h. Lung function was evaluated, using ex vivo lung perfusion (EVLP), with blood gases at different oxygen levels, pulmonary vascular resistance (PVR), lung weight, and macroscopic appearance.

Results

At FiO₂ 1.0, the PaO₂ in the DCD group was 51.7 ± 2.0 kPa and in the HBD group 68.6 ± 2.4 kPa (p < 0.01). Significantly lower PVR levels were measured in the DCD group (372 ± 31 dyne x s/cm⁵) compared to the HBD group (655 ± 45 dyne x s/cm⁵) (p < 0.001). There was no significant difference between groups in weight, compliance or signs of pulmonary thrombosis or embolization.

Conclusions

It seems as if DCD lungs exposed to 1 h of warm ischemia before 4 h of cold storage has satisfying oxygenation capacity, low PVR, normal weight and no signs of thrombosis or embolization. According to our study it seems as lungs exposed to 1 h warm ischemia without heparin might be good candidates for transplantation.

Strategies for safe donor expansion: donor management, donations after cardiac death, ex-vivo lung perfusion

PURPOSE OF REVIEW

The number of patients listed for lung transplantation largely exceeds the number of available transplantable organs because of both a shortage of organ donors and a low utilization rate of lungs from those donors. Two major innovations in recent years include the use of lungs from donations after cardiac death (DCD) and the use of ex-vivo lung perfusion (EVLP) to assess and improve injured donor lungs.

RECENT FINDINGS

DCD lung transplants now account for about 20% of lung transplants in many centres and outcomes after transplantation have been excellent with this source of donation. Clinical experience using EVLP has shown the method to be well tolerated and allow for reassessment and improvement in function from high-risk donor lungs. When these lungs were transplanted, low rates of primary graft dysfunction were achieved and long-term survival was comparable with standard transplantation. Preclinical studies have shown a great potential of EVLP as a platform for the delivery of novel therapies to repair injured donor lungs.

SUMMARY

A significant increase on the number of available lungs for transplantation is expected in the coming years with the wider use of DCD lungs and with organ-specific ex-vivo treatment strategies.

Management of the Potential Organ Donor in the ICU: Society of Critical Care Medicine/American College of Chest Physicians/Association of Organ Procurement Organizations Consensus Statement. Crit Care Med. 2015;43:1291-1325. [PMID: 25978154 DOI: 10.1097/ccm.0000000000000958]

This document was developed through the collaborative efforts of the Society of Critical Care Medicine, the American College of Chest Physicians, and the Association of Organ Procurement Organizations. Under the auspices of these societies, a multidisciplinary, multi-institutional task force was convened, incorporating expertise in critical care medicine, organ donor management, and transplantation. Members of the task force were divided into 13 subcommittees, each focused on one of the following general or organ-specific areas: death determination using neurologic criteria, donation after circulatory death determination, authorization process, general contraindications to donation, hemodynamic management, endocrine dysfunction and hormone replacement therapy, pediatric donor management, cardiac donation, lung donation, liver donation, kidney donation, small bowel donation, and pancreas donation. Subcommittees were charged with generating a series of management-related questions related to their topic. For each question, subcommittees provided a summary of relevant literature and specific recommendations. The specific recommendations were approved by all members of the task force and then assembled into a complete document. Because the available literature was overwhelmingly comprised of observational studies and case series, representing low-quality evidence, a decision was made that the document would assume the form of a consensus statement rather than a formally graded guideline. The goal of this document is to provide critical care practitioners with essential information and practical recommendations related to management of the potential organ donor, based on the available literature and expert consensus.

Expanding the donor pool: donation after cardiac death

Lung transplantation (LTx) is the definitive treatment of patients with end-stage lung disease. Availability of donor lungs remains the primary limitation and leads to substantial wait-list mortality. Efforts to expand the donor pool have included a resurgence of interest in the use of donation after cardiac death (DCD) lungs. Unique in its physiology, lung viability seems more tolerant to the variable durations of ischemia that occur in DCD donors. Initial experience with DCD LTx is promising and, in combination with ex vivo lung perfusion systems, seems a valuable opportunity to expand the lung donor pool.

Emergency medical services knowledge and attitudes about non-heart-beating donors: effect of an educational intervention

BACKGROUND

More than 750,000 people die of sudden death each year, and many are potential non-heart-beating donors (NHBDs) for lung transplant. Although critical, the role of emergency medical services (EMS) personnel in assisting with recovery of NHBD lungs has not been studied. The purpose of this study was to assess knowledge of and attitudes about NHBDs among EMS personnel, evaluate the extent to which knowledge and personal experience with organ donation is associated with attitude, and ascertain the effectiveness of an intervention designed to teach EMS professionals about NHBDs.

METHODS

EMS professionals (n = 361) completed measures of knowledge of and attitudes about NHBDs and then watched a presentation by a transplant doctor about traditional organ donation, NHBDs, and transplantation. Participants were able to ask questions during and after the presentation. Participants completed the measures again 3 months later.

RESULTS

EMS professionals had a high rate of personal experience with organ donation and positive attitudes toward traditional organ donation. However, they showed lack of knowledge about NHBDs and felt less skilled in being part of the NHBD process, consistent with knowledge scores. The educational intervention was somewhat effective in improving knowledge about NHBDs. Scores improved significantly on 5 of 13 items.

CONCLUSIONS

Lung recovery from NHBDs offers the potential of a very large supply for transplantation. This research suggests that with additional training, EMS professionals may be willing to be part of a NHBD recovery team.

Novel thermographic detection of regional malperfusion caused by a thrombosis during ex vivo lung perfusion

OBJECTIVES

Although ex vivo lung perfusion (EVLP) has been clinically applied as a novel rig to evaluate marginal donor lungs, no parameters have been reported to objectively detect regional lung damage during EVLP. The aim of this study was to investigate whether regional donor lung malperfusion-related damage caused by a thrombus could be detected by thermography during EVLP.

METHODS

Lewis rats were divided into two groups: the Thrombosis group and the Control group (n = 6 in each group). All rats were heparinized and the lungs were flushed with 20 ml of Steen solution. In the Thrombosis group, a 30-mg artificial thrombus was inserted into the left main pulmonary artery. All the lungs were perfused and ventilated using the EVLP system. Perfusion flow was increased every 2 min up to 10 ml/min. The lungs were evaluated by collecting thermographical and physiological data during EVLP.

RESULTS

Pulmonary artery pressure was higher and lung compliance was lower in the Thrombosis group compared with those in the Control group (P = 0.0005 and <0.0001, respectively). Macroscopically, no differences were seen between the perfused area and the malperfused area, whereas significant differences were detected between them by thermography. The surface temperature of both lungs in the Control group and the right lungs in the Thrombosis group rose with increasing perfusion flow, whereas the surface temperature of the left lungs in the Thrombosis group did not rise (P < 0.0001).

CONCLUSIONS

Although physiological data could possibly imply the existence of thrombi in the Thrombosis group, it could not reveal which area was obstructed by thrombi; however, thermography could detect a malperfused region. Thermographical evaluation may become a promising strategy to detect regional damage in donor lungs.

Ex vivo lung perfusion

Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. Its application in high-risk donor lungs has been successful and resulted in safe expansion of the donor pool. This article will: (I) review the technical details of EVLP; (II) the rationale behind the method; (III) report the worldwide clinical experience with the EVLP, including the Toronto technique and others; (IV) finally, discuss the growing literature on EVLP application for donation after cardiac death (DCD) lungs.

Effects of exogenous surfactant on the non-heart-beating donor lung graft in experimental lung transplantation - a stereological study

The use of non-heart-beating donor (NHBD) lungs may help to overcome the shortage of lung grafts in clinical lung transplantation, but warm ischaemia and ischaemia/reperfusion injury (I/R injury) resulting in primary graft dysfunction represent a considerable threat. Thus, better strategies for optimized preservation of lung grafts are urgently needed. Surfactant dysfunction has been shown to contribute to I/R injury, and surfactant replacement therapy is effective in enhancing lung function and structural integrity in related rat models. In the present study we hypothesize that surfactant replacement therapy reduces oedema formation in a pig model of NHBD lung transplantation. Oedema formation was quantified with (SF) and without (non-SF) surfactant replacement therapy in interstitial and alveolar compartments by means of design-based stereology in NHBD lungs 7 h after cardiac arrest, reperfusion and transplantation. A sham-operated group served as control. In both NHBD groups, nearly all animals died within the first hours after transplantation due to right heart failure. Both SF and non-SF developed an interstitial oedema of similar degree, as shown by an increase in septal wall volume and arithmetic mean thickness as well as an increase in the volume of peribron-chovascular connective tissue. Regarding intra-alveolar oedema, no statistically significant difference could be found between SF and non-SF. In conclusion, surfactant replacement therapy cannot prevent poor outcome after prolonged warm ischaemia of 7 h in this model. While the beneficial effects of surfactant replacement therapy have been observed in several experimental and clinical studies related to heart-beating donor lungs and cold ischaemia, it is unlikely that surfactant replacement therapy will overcome the shortage of organs in the context of prolonged warm ischaemia, for example, 7 h. Moreover, our data demonstrate that right heart function and dysfunctions of the pulmonary vascular bed are limiting factors that need to be addressed in NHBD.

Advances in lung preservation

After a brief review of conventional lung preservation, this article discusses the rationale behind ex vivo lung perfusion and how it has shifted the paradigm of organ preservation from conventional static cold ischemia to the utilization of functional normothermia, restoring the lung's own metabolism and its reparative processes. Technical aspects and previous clinical experience as well as opportunities to address specific donor organ injuries in a personalized medicine approach are also reviewed.

Reconditioning lungs donated after cardiac death using short-term hypothermic machine perfusion

BACKGROUND

Hypothermic machine perfusion (HMP) is widely used to preserve kidneys and livers for transplantation. This study investigated whether short-term HMP could improve the quality of lungs donated after cardiac death (DCD).

METHODS

In a clinically relevant uncontrolled DCD model, beagles were divided into two groups (n=5 each): 4 hr warm ischemia + 14 hr static cold storage (SCS group) or 4 hr warm ischemia + 12 hr SCS followed by 2 hr HMP (HMP group). HMP was performed using centrifugal perfusion with STEEN solution at approximately 10°C. In both groups, the left lungs were then transplanted and reperfused for 4 hr to evaluate the posttransplantation lung functions.

RESULTS

HMP was performed safely, not inducing any oxidative damage. The dynamic pulmonary compliance was stable during HMP, whereas the pulmonary vascular resistance significantly decreased. HMP microscopically eliminated residual microthrombi in the donor lungs just before transplantation. The lung tissue adenosine triphosphate levels 4 hr after reperfusion were significantly higher in the HMP group compared with the SCS group. The serum malondialdehyde levels and proinflammatory cytokine levels in the bronchoalveolar lavage fluid 4 hr after reperfusion were significantly lower in the HMP group than in the SCS group. The physiologic lung functions during reperfusion were significantly better in the HMP group compared with the SCS group. HMP also significantly reduced ischemia-reperfusion injury in the microscopic findings.

CONCLUSIONS

Short-term HMP could resuscitate ischemically damaged DCD lungs and ameliorate ischemia-reperfusion injury.

Protective effect of plasmin in marginal donor lungs in an ex vivo lung perfusion model

BACKGROUND

Donor lung thrombi are considered an important etiology for primary graft dysfunction in lung transplantation. We hypothesized that thrombolysis before lung transplantation could alleviate ischemia-reperfusion injury. This study was designed to evaluate the effect of the fibrinolytic agent plasmin on lungs damaged by thrombi in an ex vivo lung perfusion (EVLP) system.

METHODS

Rats were divided into control, non-plasmin, and plasmin groups (n = 7 each). In the control and plasmin groups, cardiac arrest was induced by withdrawal of mechanical ventilation without heparinization. Ventilation was restarted 150 minutes after cardiac arrest. The lungs were flushed, and the heart and lungs were excised en bloc. The lungs were perfused in the EVLP system for 60 minutes, and plasmin or placebo was administered upon EVLP initiation.

RESULTS

Fibrin/fibrinogen degradation products in the perfusate were significantly higher in the plasmin group than in the control and non-control groups (p < 0.001 for both). Plasmin administration significantly decreased pulmonary vascular resistance (plasmin vs non-plasmin, p = 0.011) and inhibited the exacerbation of dynamic compliance (plasmin vs non-plasmin, p = 0.003). Lung weight gain was less in the plasmin group than in the non-plasmin group (p = 0.04).

CONCLUSIONS

Our results confirmed that plasmin administration in an EVLP model dissolved thrombi in the lungs, resulting in reconditioning of the lungs as assessed by various physiologic parameters.

Excellent clinical outcomes from a national donation-after-determination-of-cardiac-death lung transplant collaborative

Donation-after-Determination-of-Cardiac-Death (DDCD) donor lungs can potentially increase the pool of lungs available for Lung Transplantation (LTx). This paper presents the 5-year results for Maastricht category III DDCD LTx undertaken by the multicenter Australian National DDCD LTx Collaborative. The Collaborative was developed to facilitate interaction with the Australian Organ Donation Authority, standardization of definitions, guidelines, education and audit processes. Between 2006 and 2011 there were 174 actual DDCD category III donors (with an additional 37 potentially suitable donors who did not arrest in the mandated 90 min postwithdrawal window), of whom 71 donated lungs for 70 bilateral LTx and two single LTx. In 2010 this equated to an "extra" 28% of donors utilized for LTx. Withdrawal to pulmonary arterial flush was a mean of 35.2 ± 4.0 min (range 18-89). At 24 h, the incidence of grade 3 primary graft dysfunction was 8.5%[median PaO(2)/FiO(2) ratio 315 (range 50-507)]. Overall the incidence of grade 3 chronic rejections was 5%. One- and 5-year actuarial survival was 97% and 90%, versus 90% and 61%, respectively, for 503 contemporaneous brain-dead donor lung transplants. Category III DDCD LTx therefore provides a significant, practical, additional quality source of transplantable lungs.

Ex vivo rehabilitation of non-heart-beating donor lungs in preclinical porcine model: delayed perfusion results in superior lung function

OBJECTIVES

Ex vivo lung perfusion (EVLP) is a promising modality for the evaluation and treatment of marginal donor lungs. The optimal timing of EVLP initiation and the potential for rehabilitation of donor lungs with extended warm ischemic times is unknown. The present study compared the efficacy of different treatment strategies for uncontrolled non-heart-beating donor lungs.

METHODS

Mature swine underwent hypoxic arrest, followed by 60 minutes of no-touch warm ischemia. The lungs were harvested and flushed with 4°C Perfadex. Three groups (n = 5/group) were stratified according to the preservation method: cold static preservation (CSP; 4 hours of 4°C storage), immediate EVLP (I-EVLP: 4 hours EVLP at 37°C), and delayed EVLP (D-EVLP; 4 hours of CSP followed by 4 hours of EVLP). The EVLP groups were perfused with Steen solution supplemented with heparin, methylprednisolone, cefazolin, and an adenosine 2A receptor agonist. The lungs then underwent allotransplantation and 4 hours of recipient reperfusion before allograft assessment for resultant ischemia-reperfusion injury.

RESULTS

The donor blood oxygenation (partial pressure of oxygen/fraction of inspired oxygen ratio) before death was not different between the groups. The oxygenation after transplantation was significantly greater in the D-EVLP group than in the I-EVLP or CSP groups. The mean airway pressure, pulmonary artery pressure, and expression of interleukin-8, interleukin-1β, and tumor necrosis factor-α were all significantly reduced in the D-EVLP group. Post-transplant oxygenation exceeded the acceptable clinical levels only in the D-EVLP group.

CONCLUSIONS

Uncontrolled non-heart-beating donor lungs with extended warm ischemia can be reconditioned for successful transplantation. The combination of CSP and EVLP in the D-EVLP group was necessary to obtain optimal post-transplant function. This finding, if confirmed clinically, will allow expanded use of nonheart-beating donor lungs.