Experience with the first 50 ex vivo lung perfusions in clinical transplantation

Human leukocyte antigen-DR13 and DR15 are associated with short-term lung transplant outcomes

BACKGROUND

Lung transplantation outcomes are among the least favorable, with most recipients eventually developing bronchiolitis obliterans syndrome (BOS) and subsequent graft failure. The presence of human leukocyte antigen (HLA)-DR has been implicated in the pathogenesis of BOS and may play a role in these poor outcomes.

METHODS

Lung transplant donor and recipient data were retrospectively gathered from the United Network for Organ Sharing database from January 2006 to June 2013. Donor and recipient characteristics, proportion of recipients treated for first year rejection, and 5-y rates of survival and freedom from BOS were determined according to HLA-DR1, -DR7, -DR13, and -DR15 status in both donor and recipient. Each HLA-DR allele was stratified by donor-recipient pair positivity status.

RESULTS

A total of 7402 lung transplant recipients met the inclusion and exclusion criteria. There were significant but small differences in donor and recipient characteristics for each HLA-DR group. The recipients in the D(-)R(+) pairing for HLA-DR13 and those in the D(+)R(-) pairing for HLA-DR15 had significantly higher rates of receiving treatment for rejection within the first year after transplant (P = 0.024 and P = 0.001, respectively). There were no differences in 5-y survival or freedom from BOS for any of the four HLA-DR alleles studied.

CONCLUSIONS

There are higher rates of patients treated for rejection within the first year who are either negative for the HLA-DR15 allele but received a donor-positive lung or positive for the HLA-DR13 allele but received a donor-negative lung for that allele. However, these differences do not appear to affect long-term outcomes.

Expanding the lung donor pool: advancements and emerging pathways

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.

Altered Immunogenicity of Donor Lungs via Removal of Passenger Leukocytes Using Ex Vivo Lung Perfusion

Passenger leukocyte transfer from the donor lung to the recipient is intrinsically involved in acute rejection. Direct presentation of alloantigen expressed on donor leukocytes is recognized by recipient T cells, promoting acute cellular rejection. We utilized ex vivo lung perfusion (EVLP) to study passenger leukocyte migration from donor lungs into the recipient and to evaluate the effects of donor leukocyte depletion prior to transplantation. For this purpose, female pigs received male left lungs either following 3 h of EVLP or retrieved using standard protocols. Recipients were monitored for 24 h and sequential samples were collected. EVLP-reduced donor leukocyte transfer into the recipient and migration to recipient lymph nodes was markedly reduced. Recipient T cell infiltration of the donor lung was significantly diminished via EVLP. Donor leukocyte removal during EVLP reduces direct allorecognition and T cell priming, diminishing recipient T cell infiltration, the hallmark of acute rejection.

Lung Transplantation in Cystic Fibrosis: Trends and Controversies

This article is not an overview of all facets of lung transplantation in cystic fibrosis (CF), but rather it is intended as a review of current allocation controversies, as well as of trends in diagnostics and management in lung transplant recipients and in patients with end-stage lung disease. Despite changes in donor and recipient selection, long-term survival in pediatric lung transplant has continued to be limited by chronic lung allograft dysfunction (CLAD). Due to, in part, this short survival benefit, transplant continues to be an appropriate option for only a subset of pediatric patients with CF. The feasibility of transplant as a therapeutic option is also affected by the limited pediatric organ supply, which has moreover contributed to controversy over lung allocation. Debates over the allocation of this scarce resource, however, may also help to drive innovation in the field of lung transplant. Longer pretransplant survival-as aided by new lung bypass technologies, for example-could help to alleviate organ shortages, as well as facilitate the transport of organs to suitable pediatric recipients. Improved diagnosis and treatment for CLAD and for antibody-mediated rejection have the potential to extend survival in pediatric lung transplant. Regardless, the relative rarity of transplant could pose future challenges for pediatric lung transplant programs, which require adequate numbers of patients to maintain proper expertise.

Machine perfusion enhances hepatocyte isolation yields from ischemic livers

BACKGROUND

High-quality human hepatocytes form the basis of drug safety and efficacy tests, cell-based therapies, and bridge-to-transplantation devices. Presently the only supply of cells derives from an inadequate pool of suboptimal disqualified donor livers. Here we evaluated whether machine perfusion could ameliorate ischemic injury that many of these livers experience prior to hepatocyte isolation.

METHODS

Non-heparinized female Lewis rat livers were exposed to an hour of warm ischemia (34°C) and then perfused for 3h. Five different perfusion conditions that utilized the cell isolation apparatus were investigated, namely: (1) modified Williams Medium E and (2) Lifor, both with active oxygenation (95%O(2)/5%CO(2)), as well as (3) Lifor passively oxygenated with ambient air (21%O(2)/0.04%CO(2)), all at ambient temperatures (20 ± 2°C). At hypothermic temperatures (5 ± 1°C) and under passive oxygenation were (4) University of Wisconsin solution (UW) and (5) Vasosol. Negative and positive control groups comprised livers that had ischemia (WI) and livers that did not (Fresh) prior to cell isolation, respectively.

RESULTS

Fresh livers yielded 32 ± 9 million cells/g liver while an hour of ischemia reduced the cell yield to 1.6 ± 0.6 million cells/g liver. Oxygenated Williams Medium E and Lifor recovered yields of 39 ± 11 and 31 ± 2.3 million cells/g liver, respectively. The passively oxygenated groups produced 15 ± 7 (Lifor), 13 ± 7 (Vasosol), and 10 ± 6 (UW)million cells/g liver. Oxygenated Williams Medium E was most effective at sustaining pH values, avoiding the accumulation of lactate, minimizing edematous weight gain and producing bile during perfusion.

CONCLUSIONS

Machine perfusion results in a dramatic increase in cell yields from livers that have had up to an hour of warm ischemia, but perfusate choice significantly impacts the extent of recovery. Oxygenated Williams Medium E at room temperature is superior to Lifor, UW and Vasosol, largely facilitated by its high oxygen content and low viscosity.

Assessment of donor heart viability during ex vivo heart perfusion

Ex vivo heart perfusion (EVHP) may facilitate resuscitation of discarded donor hearts and expand the donor pool; however, a reliable means of demonstrating organ viability prior to transplantation is required. Therefore, we sought to identify metabolic and functional parameters that predict myocardial performance during EVHP. To evaluate the parameters over a broad spectrum of organ function, we obtained hearts from 9 normal pigs and 37 donation after circulatory death pigs and perfused them ex vivo. Functional parameters obtained from a left ventricular conductance catheter, oxygen consumption, coronary vascular resistance, and lactate concentration were measured, and linear regression analyses were performed to identify which parameters best correlated with myocardial performance (cardiac index: mL·min–1·g–1). Functional parameters exhibited excellent correlation with myocardial performance and demonstrated high sensitivity and specificity for identifying hearts at risk of poor post-transplant function (ejection fraction: R2 = 0.80, sensitivity = 1.00, specificity = 0.85; stroke work: R2 = 0.76, sensitivity = 1.00, specificity = 0.77; minimum dP/dt: R2 = 0.74, sensitivity = 1.00, specificity = 0.54; tau: R2 = 0.51, sensitivity = 1.00, specificity = 0.92), whereas metabolic parameters were limited in their ability to predict myocardial performance (oxygen consumption: R2 = 0.28; coronary vascular resistance: R2 = 0.20; lactate concentration: R2 = 0.02). We concluded that evaluation of functional parameters provides the best assessment of myocardial performance during EVHP, which highlights the need for an EVHP device capable of assessing the donor heart in a physiologic working mode.

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.

Evaluating acellular versus cellular perfusate composition during prolonged ex vivo lung perfusion after initial cold ischaemia for 24 hours

Normothermic ex vivo lung perfusion (EVLP) has developed as a powerful technique to evaluate particularly marginal donor lungs prior to transplantation. In this study, acellular and cellular perfusate compositions were compared in an identical experimental setting as no consensus has been reached on a preferred technique yet. Porcine lungs underwent EVLP for 12 h on the basis of an acellular or a cellular perfusate composition after 24 h of cold ischaemia as defined organ stress. During perfusion, haemodynamic and respiratory parameters were monitored. After EVLP, the lung condition was assessed by light and transmission electron microscopy. Aerodynamic parameters did not show significant differences between groups and remained within the in vivo range during EVLP. Mean oxygenation indices were 491 ± 39 in the acellular group and 513 ± 53 in the cellular group. Groups only differed significantly in terms of higher pulmonary artery pressure and vascular resistance in the cellular group. Lung histology and ultrastructure were largely well preserved after prolonged EVLP and showed only minor structural alterations which were similarly present in both groups. Prolonged acellular and cellular EVLP for 12 h are both feasible with lungs prechallenged by ischaemic organ stress. Physiological and ultrastructural analysis showed no superiority of either acellular or cellular perfusate composition.

Clinical Outcome of Patients Transplanted with Marginal Donor Lungs via Ex Vivo Lung Perfusion Compared to Standard Lung Transplantation

BACKGROUND

Lung transplantation is limited by a scarcity of suitable donors resulting in high waiting list mortality. Ex vivo lung perfusion (EVLP) allows the evaluation and reconditioning of marginal donor lungs for use in transplantation. This study aimed to compare clinical outcome of patients transplanted with marginal organs by means of EVLP with a standard lung transplant cohort through a multicenter open trial.

METHODS

Group 1 (n = 9) included patients transplanted using EVLP reconditioned marginal lungs. Group 2 (n = 46) consisted of date-matched patients transplanted using standard transplantation of acceptable lungs. The primary composite endpoint included acute rejection and infection at 12 months after transplantation.

RESULTS

There was no significant difference in the overall incidence of acute rejection (P = 0.754) and the number of treated infection episodes (proven/probable pneumonia; P = 0.857/0.368 and proven/probable tracheobronchitis; P = 0.226/0.529) up to 12 months after transplantation, between group 1 and group 2. Additionally, there was no significant difference in early clinical outcome, including intensive care unit stay, hospital stay, and 1 year mortality between the two groups (P = 0.338, P = 0.112 and P = 0.372, respectively).

DISCUSSION

This multicenter study demonstrates that EVLP is associated with no adverse effect on clinical outcome, including the incidence of acute rejection and infection after lung transplantation.

Current State of Pediatric Lung Transplantation

Cardiothoracic transplantation has significantly impacted the lives of pediatric patients with advanced cardiopulmonary failure. The current state of lung transplantation in children as well as its ongoing and future challenges are discussed.

Hemofiltration in ex vivo lung perfusion-a study in experimentally induced pulmonary edema

OBJECTIVES

Ex vivo lung perfusion (EVLP) can potentially reduce pulmonary edema. In a pig model with induced pulmonary edema, we evaluated the effect of hemofiltration (HF) during EVLP on lung function, perfusate oncotic pressure, and lung weight.

METHODS

In anesthetized pigs (n = 14), pulmonary edema was induced by a balloon in the left atrium, combined with crystalloid infusion (20 mL/kg), for 2 hours. The lungs were harvested, stored cold for 2 hours, and randomized to EVLP, with or without a hemofilter (HF and noHF groups, respectively, n = 7 for each). EVLP was performed with cellular perfusate at a hematocrit of 10% to 15%. Oncotic pressure, lung performance, and weight were measured before and after 180 minutes of EVLP reconditioning with or without HF.

RESULTS

After in vivo induction of edema, arterial oxygen tension (Pao2)/inspired oxygen fraction (Fio2), and compliance decreased by 63% and 16%, respectively. Pao2/Fio2 was considerably improved at first evaluation ex vivo in both groups. HF increased oncotic pressure by 43% and decreased lung weight by 15%. The effects were negligible in the noHF group. Compliance decreased in both groups during reconditioning, although less so in the HF group (P < .05). Pao2/Fio2, shunt fraction, and oxygen saturation remained unchanged in both groups. Pulmonary flow index decreased in both groups, and was partially reversed by nitroglycerin. Dorsal atelectatic consolidations were seen in both groups.

CONCLUSIONS

In this lung-edema model, EVLP reconditioning with hyperoncotic solution did not affect the degree of lung edema. HF during EVLP increased perfusate oncotic pressure, decreased lung weight with beneficial effects on compliance, but did not improve lung oxygenation capacity.

Protein expression profiling predicts graft performance in clinical ex vivo lung perfusion

OBJECTIVES

To study the impact of ex vivo lung perfusion (EVLP) on cytokines, chemokines, and growth factors and their correlation with graft performance either during perfusion or after transplantation.

BACKGROUND

EVLP is a modern technique that preserves lungs on normothermia in a metabolically active state. The identification of biomarkers during clinical EVLP can contribute to the safe expansion of the donor pool.

METHODS

High-risk brain death donors and donors after cardiac death underwent 4 to 6 hours EVLP. Using a multiplex magnetic bead array assay, we evaluated analytes in perfusate samples collected at 1 hour and 4 hours of EVLP. Donor lungs were divided into 3 groups: (I) Control: bilateral transplantation with good early outcome [absence of primary graft dysfunction- (PGD) grade 3]; (II) PGD3: bilateral transplantation with PGD grade 3 anytime within 72 hours; (III) Declined: lungs unsuitable for transplantation after EVLP.

RESULTS

Of 50 cases included in this study, 27 were in Control group, 7 in PGD3, and 16 in Declined. From a total of 51 analytes, 34 were measurable in perfusates. The best marker to differentiate declined lungs from control lungs was stem cell growth factor -β [P < 0.001, AUC (area under the curve) = 0.86] at 1 hour. The best markers to differentiate PGD3 cases from controls were interleukin-8 (P < 0.001, AUC = 0.93) and growth-regulated oncogene-α (P = 0.001, AUC = 0.89) at 4 hours of EVLP.

CONCLUSIONS

Perfusate protein expression during EVLP can differentiate lungs with good outcome from lungs PGD3 after transplantation. These perfusate biomarkers can be potentially used for more precise donor lung selection improving the outcomes of transplantation.

Lung transplantation with donation after circulatory determination of death donors and the impact of ex vivo lung perfusion

The growing demand for suitable lungs for transplantation drives the quest for alternative strategies to expand the donor pool. The aim of this study is to evaluate the outcomes of lung transplantation (LTx) with donation after circulatory determination of death (DCDD) and the impact of selective ex vivo lung perfusion (EVLP). From 2007 to 2013, 673 LTx were performed, with 62 (9.2%) of them using DCDDs (seven bridged cases). Cases bridged with mechanical ventilation/extracorporeal life support were excluded. From 55 DCDDs, 28 (51%) underwent EVLP. Outcomes for LTx using DCDDs and donation after neurological determination of death (DNDD) donors were similar, with 1 and 5-year survivals of 85% and 54% versus 86% and 62%, respectively (p = 0.43). Although comparison of survival curves between DCDD + EVLP versus DCDD-no EVLP showed no significant difference, DCDD + EVLP cases presented shorter hospital stay (median 18 vs. 23 days, p = 0.047) and a trend toward shorter length of mechanical ventilation (2 vs. 3 days, p = 0.059). DCDDs represent a valuable source of lungs for transplantation, providing similar results to DNDDs. EVLP seems an important technique in the armamentarium to safely increase lung utilization from DCDDs; however, further studies are necessary to better define the role of EVLP in this context.

Could Ex Vivo Lung Perfusion Be a Platform to Decrease the Incidence of Chronic Lung Allograft Dysfunction?

The number of patients requiring lung transplantation is increasing, with a significant unmet demand for grafts. Ex vivo lung perfusion has been developed to increase graft recruitment. The major complications of lung transplantation include chronic allograft dysfunction (CLAD) whose cumulative incidence ranges from 43-80% within the first 5 years of transplantation. Many risk factors are listed for development of CLAD and almost all of those risk factors would involve activation of Toll-like receptors. This paper represents the author's overview regarding the development of CLAD as a complication of lung transplantation and the possible protective potential of ex vivo lung perfusion in this regard.

Ex vivo lung perfusion - state of the art in lung donor pool expansion

Lung transplantation remains the gold standard for patients with end-stage lung disease. Nevertheless, the number of suitable donor lungs for the increasing number of patients on the waiting list necessitates alternative tools to expand the lung donor pool. Modern preservation and lung assessment techniques could contribute to improved function in previously rejected lungs. Ex vivo lung perfusion (EVLP) already demonstrated its value in identification of transplantable grafts from the higher risk donor pool. Moreover, lungs from EVLP did not show significantly different postoperative results compared to standard criteria lungs. This could be explained by the reduction of the ischemia-reperfusion injury through EVLP application. The aim of this article is to review technical characteristics and the growing clinical EVLP experience with special attention to EVLP application for donation after cardiac death (DCD) lungs.

Hydrogen preconditioning during ex vivo lung perfusion improves the quality of lung grafts in rats

BACKGROUND

Although the benefits of ex vivo lung perfusion (EVLP) have been globally advocated, the potentially deleterious effects of applying EVLP, in particular activation of proinflammatory cascades and alteration of metabolic profiles, are rarely discussed. This study examined proinflammatory events and metabolic profiles in lung grafts on EVLP and tested whether preconditioning lung grafts with inhaled hydrogen, a potent, cytoprotective gaseous signaling molecule, would alter the lungs' response to EVLP.

METHODS

Rat heart-lung blocks were mounted on an acellular normothermic EVLP system for 4 hr and ventilated with air or air supplemented with 2% hydrogen. Arterial and airway pressures were monitored continuously; perfusate was sampled hourly to examine oxygenation. After EVLP, the lung grafts were transplanted orthotopically into syngeneic rats, and lung function was examined.

RESULTS

Placing lung grafts on EVLP resulted in significant upregulation of the messenger RNAs for several proinflammatory cytokines, higher glucose consumption, and increased lactate production. Hydrogen administration attenuated proinflammatory changes during EVLP through upregulation of the heme oxygenase-1. Hydrogen administration also promoted mitochondrial biogenesis and significantly decreased lactate production. Additionally, in the hydrogen-treated lungs, the expression of hypoxia-inducible factor-1 was significantly attenuated during EVLP. These effects were maintained throughout EVLP and led to better posttransplant lung graft function in the recipients of hydrogen-treated lungs.

CONCLUSIONS

Lung grafts on EVLP exhibited prominent proinflammatory changes and compromised metabolic profiles. Preconditioning lung grafts using inhaled hydrogen attenuated these proinflammatory changes, promoted mitochondrial biogenesis in the lungs throughout the procedure, and resulted in better posttransplant graft function.

Acute kidney injury after ex vivo lung perfusion (EVLP)

BACKGROUND

Ex vivo lung perfusion (EVLP) identifies viability for marginal organs but complicates and lengthens lung transplantation surgery. Preliminary evidence supports equivalency for EVLP-assisted versus traditional (non-EVLP) procedures regarding graft function, postoperative course, mortality, and survival. However, acute kidney injury (AKI), a common serious complication of lung transplantation, has not been assessed. We tested the hypothesis that EVLP-assisted and non-EVLP lung transplantations are associated with different AKI rates.

METHODS

Demographic, procedural, and renal data were gathered for 13 EVLP-viable lung transplantations and a non-EVLP group matched 4:1 for single versus double, pulmonary disease, and age. AKI was defined by AKI Network (AKIN) criteria and peak creatinine rise relative to baseline (Δ%Cr) during the 1st 10 postoperative days. Chi-square was performed for AKIN and 2-tailed t test for %ΔCr.

RESULTS

Patient and procedural characteristics were similar between the groups. One non-EVLP patient required postoperative dialysis. AKI rates were also similar, as assessed by both AKIN (EVLP 7/13 (54%) vs non-EVLP 32/52 (62%); P = .61) and %ΔCr (EVLP 91 ± 81% vs non-EVLP 72 ± 62%; P = .63).

CONCLUSIONS

We did not observe different AKI rates between EVLP-assisted and traditional lung transplant procedures. Although 1 non-EVLP patient required dialysis, AKI rates were otherwise similar. These findings further support EVLP as a strategy to expand the organ pool and reduce concerns for high-renal risk recipients. The small sample size and retrospective design are limitations. However, our sample size is similar to other reports, and it is the first to analyze AKI after EVLP-assisted lung transplantation. Larger multicenter prospective studies are needed.

Outcomes of intraoperative extracorporeal membrane oxygenation versus cardiopulmonary bypass for lung transplantation

OBJECTIVE

The study objective was to compare the outcomes of intraoperative extracorporeal membrane oxygenation versus cardiopulmonary bypass support in lung transplantation.

METHODS

We performed a retrospective cohort study from a prospective database of adult lung transplantations performed at the University of Toronto from 2007 to 2013. Among 673 lung transplantations performed in the study period, 267 (39.7%) required cardiopulmonary support. There were 39 cases of extracorporeal membrane oxygenation (2012-2013) and 228 cases of cardiopulmonary bypass (2007-2013). Patients who were bridged with extracorporeal life support, underwent a concomitant cardiac procedure, received a combined liver or heart transplant, were colonized with Burkholderia cenocepacia, or required emergency cannulation for cardiopulmonary support were excluded. Finally, 33 extracorporeal membrane oxygenation cases were matched with 66 cases of cardiopulmonary bypass according to age (±10 years), lung transplantation indication, and procedure type (bilateral vs single lung transplantation).

RESULTS

Recipient factors such as body mass index and gender were not different between extracorporeal membrane oxygenation and cardiopulmonary bypass groups. Furthermore, donor variables were similar, including age, body mass index, last PaO2/FiO2 ratio, smoking history, positive airway cultures, and donor type (brain death and donation after cardiac death). Early outcomes, such as mechanical ventilation requirement, length of intensive care unit stay, and length of hospital stay, significantly favored extracorporeal membrane oxygenation (median 3 vs 7.5 days, P = .005; 5 vs 9.5 days, P = .026; 19 vs 27 days, P = .029, respectively). Perioperative blood product transfusion requirement was lower in the extracorporeal membrane oxygenation group. The 90-day mortality for the extracorporeal membrane oxygenation group was 6% versus 15% for cardiopulmonary bypass (P = .32).

CONCLUSIONS

Extracorporeal membrane oxygenation may be considered as the first choice of intraoperative cardiorespiratory support for lung transplantation.

Advanced therapies for COPD-What's on the horizon? Progress in lung volume reduction and lung transplantation

Advanced chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity. Treatment options beyond conventional medical therapies are limited to a minority of patients. Lung volume reduction surgery (LVRS) although effective in selected subgroups of patients is not commonly undertaken. Morbidity associated with the procedure has contributed to this low utilisation. In response to this, less invasive bronchoscopic lung volume techniques are being developed to attempt to mitigate some of the risks and costs associated with surgery. Of these, endobronchial valve therapy is the most comprehensively studied although the presence of collateral ventilation in a significant proportion of patients has compromised its widespread utility. Bronchial thermal vapour ablation and lung volume reduction (LVR) coils are not dependent on collateral ventilation. These techniques have shown promise in early clinical trials; ongoing work will establish whether they have a role in the management of advanced COPD. Lung transplantation, although effective in selected patients for palliation of symptoms and improving survival, is limited by donor organ availability and economic constraint. Reconditioning marginal organs previously declined for transplantation with ex vivo lung perfusion (EVLP) is one potential strategy in improving the utilisation of donor organs. By increasing the donor pool, it is hoped lung transplantation might be more accessible for patients with advanced COPD into the future.

Combined liver and lung transplantation with extended normothermic lung preservation in a patient with end-stage emphysema complicated by drug-induced acute liver failure

Isolated lung transplantation (LuTx) and liver transplantation are established treatments for irreversible lung and liver failure. Combined liver and lung transplantation (cLiLuTx) is a less common, but approved therapy of combined organ failure, mostly applied in patients suffering from progressive cystic fibrosis and advanced liver disease. We report a patient who was listed for LuTx due to end-stage chronic obstructive pulmonary disease and who developed drug-induced acute hepatic failure. The only therapeutic option was hyper-urgent cLiLuTx. To correct the poor coagulation in order to reduce the per-operative risk of bleeding, the liver was transplanted first. In anticipation of the longer lung preservation time, cold flushed lungs were preserved on a portable lung perfusion device for ex vivo normothermic perfusion for 11 h 15 min, transplanted sequentially off-pump, and reperfused after a total ex vivo time of 13 h 32 min and 16 h for the first and second lung, respectively. Ten months later, the patient is doing well and no rejection occurred. Normothermic ex vivo lung perfusion may help to prolong preservation time, facilitating long-distance transport and combined organ transplantation.

Reoperative lung transplantation for donor-derived pulmonary mucormycosis

A 64-year-old male with end-stage lung disease underwent right orthotopic lung transplantation. After doing well initially, he developed acute hypoxemic respiratory failure with allograft pneumonia. Donor operative cultures demonstrated mold of the Mucor species, which were corroborated by donor endobronchial cultures obtained near the right mainstem bronchial anastomosis. The patient was treated with reoperative bilateral orthotopic lung transplantation in combination with antifungal agents. The operation was performed successfully, using lungs donated after cardiac death and treated with ex vivo lung perfusion. The patient has recovered well, remaining on room air with good allograft function, without evidence of fungal disease.

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.

Indications and outcomes in adult lung transplantation

Lung transplantation (LTx) is a treatment option for end-stage lung disease that would be otherwise fatal for specific patient populations. The most common indications for LTx in adults remain to be chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, alpha-1 antitrypsin deficiency, and idiopathic pulmonary arterial hypertension. Recent trends include performing re-transplantation while more patients over the age of 65 years are undergoing LTx. Even with these tendencies, slight improvements in survival have occurred. This article briefly reviews recent developments in adults undergoing LTx.

Lung transplantation from initially rejected donors after ex vivo lung reconditioning: the French experience

OBJECTIVES

Only 15% of brain death donors are considered suitable for lung transplantation (LTx). The normothermic ex vivo lung perfusion technique is used to potentially increase the availability of high-risk lung donors. We report our experience of LTx with initially rejected donors after ex vivo lung reconditioning (EVLR).

METHODS

From April 2011 to May 2013, we performed EVLR for 32 pairs of donor lungs deemed unsuitable for transplantation and rejected by the 11 French lung transplant teams. After EVLR, lungs with acceptable function were transplanted. During the same period, 81 double-lung transplantations (DLTx) were used as controls.

RESULTS

During EVLR, 31 of 32 donor lungs recovered physiological function with a median PO2/FiO2 ratio increasing from 274 (range 162-404) mmHg to 511 (378-668) mmHg at the end of EVLR (P < 0.0001). Thirty-one DLTx were performed. The incidence of primary graft dysfunction 72 h after LTx was 9.5% in the EVLR group and 8.5% in the control group (P = 1). The median time of extubation, intensive care unit and hospital lengths of stay were 1, 9 and 37 days in the EVLR group and 1 (P = 0.17), 6 (P = 0.06) and 28 days (P = 0.09) in the control group, respectively. Thirty-day mortality rates were 3.3% (n = 1) in the EVLR group and 3.7% (n = 3) in the control group (P = 0.69). One-year survival rates were 93% in the EVLR group and 91% in the control group.

CONCLUSIONS

EVLR is a reliable and repeatable technique that offers a significant increase of available donors. The results of LTx with EVLR lungs are similar to those obtained with conventional donors.

Incidence and severity of primary graft dysfunction after lung transplantation using rejected grafts reconditioned with ex vivo lung perfusion

OBJECTIVES

Ex vivo lung perfusion (EVLP) is a novel technique used to evaluate and recondition marginal or rejected grafts. Primary graft dysfunction (PGD) is a major early complication after lung transplantation (LTx). The use of marginal or initially rejected grafts may increase its incidence and severity. The aim of this study is to evaluate the incidence of PGD after LTx using rejected grafts reconditioned with EVLP.

METHODS

PGD has been evaluated immediately after LTx (t0) and after 72 h (t72) in patients receiving standard (Group A) or reconditioned (Group B) grafts. EVLP was performed using a controlled acellular perfusion according to the Toronto technique.

RESULTS

From July 2011 to February 2013, 36 LTxs have been performed: 28 patients (21 M/7 F, mean age 51.7 ± 14.7 years) in Group A and 8 (6 M/2 F, mean age 46.6 ± 9.8 years) in Group B (successful recondition rate of 73%, 8 of 11 cases). Incidence rate of PGD 3 at t0 and at t72 (Group A versus Group B) was 50 vs 37% (P = NS) and 25 vs 0% (P = NS), respectively. Post-transplant extracorporeal membrane oxygenation was required in 5 and 2 patients in Groups A and B, respectively (P = NS).

CONCLUSIONS

The use of initially rejected grafts treated with EVLP does not increase the incidence and severity of PGD after LTx. Although comparison of PGD 3 incidence in the two groups did not reach a statistical difference, all EVLP patients suffering from severe PGD early after transplant recovered normal lung function at 72 h, suggesting a protective role of EVLP against PGD occurrence and severity.

Ex vivo lung perfusion allows successful transplantation of donor lungs from hanging victims

BACKGROUND

Donor lungs acquired from victims of asphyxiation by hanging are not routinely used for lung transplantation because of the associated lung injury. Ex vivo lung perfusion (EVLP) is a technique to evaluate marginal donor lungs before transplantation. We report here our experience with the use of EVLP in donor lungs procured from victims of asphyxia by hanging.

METHODS

Lungs from 5 donors who became brain dead secondary to hanging were evaluated by EVLP. Donor organs were perfused according to trial protocol. Donor lungs were accepted for transplantation if they maintained a PaO2 greater than or equal to 350 mm Hg, had a clear roentgenogram, and had no significant worsening of physiologic metrics.

RESULTS

Perfused organs included single and double lung blocs, and all were perfused without technical incident. Three of the 5 donor organs evaluated met criteria for transplantation after 3 hours of EVLP and were transplanted. Donor organs rejected for transplantation showed either signs of worsening PaO2 or deterioration of physiologic metrics. There were no intraoperative complications in the patients who underwent transplantation, and all were alive at 30 days.

CONCLUSIONS

We report here the successful use of EVLP to assess donor lungs acquired from victims of asphyxiation by hanging. The use of EVLP in this particular group of donors has the potential to expand the available donor pool. We demonstrate that EVLP is a viable option for evaluating the function of lung allografts before transplantation and would recommend that all donor lungs obtained from hanging victims undergo EVLP to assess their suitability for transplantation.

Ex vivo lung perfusion to improve donor lung function and increase the number of organs available for transplantation

This paper describes the initial clinical experience of ex vivo lung perfusion (EVLP) at the Fondazione Ca’ Granda in Milan between January 2011 and May 2013. EVLP was considered if donor PaO₂/FiO₂ was below 300 mmHg or if lung function was doubtful. Donors with massive lung contusion, aspiration, purulent secretions, pneumonia, or sepsis were excluded. EVLP was run with a low-flow, open atrium and low hematocrit technique. Thirty-five lung transplants from brain death donors were performed, seven of which after EVLP. EVLP donors were older (54 ± 9 years vs. 40 ± 15 years, EVLP versus Standard, P < 0.05), had lower PaO₂/FiO₂ (264 ± 78 mmHg vs. 453 ± 119 mmHg, P < 0.05), and more chest X-ray abnormalities (P < 0.05). EVLP recipients were more often admitted to intensive care unit as urgent cases (57% vs. 18%, P = 0.05); lung allocation score at transplantation was higher (79 [40–84] vs. 39 [36–46], P < 0.05). After transplantation, primary graft dysfunction (PGD₇₂ grade 3, 32% vs. 28%, EVLP versus Standard, P = 1), mortality at 30 days (0% vs. 0%, P = 1), and overall survival (71% vs. 86%, EVLP versus Standard P = 0.27) were not different between groups. EVLP enabled a 20% increase in available donor organs and resulted in successful transplants with lungs that would have otherwise been rejected (ClinicalTrials.gov number: NCT01967953).

Donation after circulatory death: current practices, ongoing challenges, and potential improvements

Organ donation after circulatory death (DCD) has been endorsed by the World Health Organization and is practiced worldwide. This overview examines current DCD practices, identifies problems and challenges, and suggests clinical strategies for possible improvement. Although there is uniform agreement on DCD donor candidacy (ventilator-dependent individuals with nonrecoverable or irreversible neurologic injury not meeting brain death criteria), there are variations in all aspects of DCD practice. Utilization of DCD organs is limited by hypoxia, hypotension, reduced--then absent--organ perfusion, and ischemia/reperfusion syndrome. Nevertheless, DCD kidneys exhibit comparable function and survival to donors with brain death kidneys, although they have higher rates of primary graft nonfunction, delayed graft function, discard, and retrieval associated injury. Concern over ischemic organ injury underscores the reluctance to recover extrarenal DCD organs since lack of medical therapy to support inadequate allograft function limits their acceptability. Nevertheless, limited results with DCD pancreas, liver, and lung allografts (but not heart) are now approaching that of donors with brain death organs. Pretransplant machine perfusion of DCD kidneys (vs. static storage) may reduce delayed graft function but has no effect on long-term organ function and survival. Normothermic regional perfusion used during DCD abdominal organ retrieval may reduce ischemic organ injury and increase the number of usable organs, although critical confirmative studies have yet to be done. Minor increases in usable DCD kidneys could accrue from increased use of pediatric DCD kidneys and from selective use of DCD/ECD kidneys, whereas a modest increase could result through utilization of donors declared dead beyond 1 hr from withdrawal of life support therapy. A significant increase in transplantable kidneys could be achieved by extension of the concept of living kidney donation in relation to imminent death of potential DCD donors. Progress in research to identify, prevent, and repair DCD-associated organ retrieval injury should improve utilization of DCD organs. Recent results using ex situ pretransplant organ perfusion of DCD organs has been encouraging in this regard.

Should we reconsider lung transplantation through uncontrolled donation after circulatory death?

Lung transplantation through controlled donation after circulatory death (cDCD) has slowly gained universal acceptance with reports of equivalent outcomes to those through donation after brain death. In contrast, uncontrolled DCD (uDCD) lung use is controversial and requires ethical, legal and medical complexities to be addressed in a limited time. Consequently, uDCD lung use has not previously been reported in the United States. Despite these potential barriers, we present a case of a patient with multiple gunshot wounds to the head and the body who was unsuccessfully resuscitated and ultimately became an uDCD donor. A cytomegalovirus positive recipient who had previously consented for CDC high-risk, DCD and participation in the NOVEL trial was transplanted from this uDCD donor, following 3 h of ex vivo lung perfusion. The postoperative course was uneventful, and the recipient was discharged home on day 9. While this case represents a "best-case scenario," it illustrates a method for potential expansion of the lung allograft pool through uDCD after unsuccessful resuscitation in hospitalized patients.

Real-time measurements of endogenous carbon monoxide production in isolated pig lungs

Ischemia-reperfusion injuries are a critical determinant of lung transplantation success. The endogenous production of carbon monoxide (CO) is triggered by ischemia-reperfusion injuries. Our aim was, therefore, to assess the feasibility of exhaled CO measurements during the ex vivo evaluation of lungs submitted to ischemia-reperfusion injuries. Five pigs were euthanized and their lungs removed after pneumoplegia. After cold storage (30 min, 4°C), the lungs were connected to an extracorporeal membrane oxygenation circuit, slowly warmed-up, and ventilated. At the end of a 45-min steady state, CO measurements were performed by optical-feedback cavity-enhanced absorption spectroscopy, a specific laser-based technique for noninvasive and real-time low gas concentration measurements. Exhaled CO concentration from isolated lungs reached 0.45±0.19  ppmv and was above CO concentration in ambient air and in medical gas. CO variations peaked during the expiratory phase. Changes in CO concentration in ambient air did not alter CO concentrations in isolated lungs. Exhaled CO level was also found to be uncorrelated to heme oxygenase (HO-1) gene expression. These results confirm the feasibility of accurate and real-time CO measurement in isolated lungs. The presented technology could help establishing the exhaled CO concentration as a biomarker of ischemia-reperfusion injury in ex vivo lung perfusion.