The use of non-heart-beating lung donors category III can increase the donor pool

Lung Transplantation in Controlled Donation after Circulatory-Determination-of-Death Using Normothermic Abdominal Perfusion

The main limitation to increased rates of lung transplantation (LT) continues to be the availability of suitable donors. At present, the largest source of lung allografts is still donation after the neurologic determination of death (brain-death donors, DBD). However, only 20% of these donors provide acceptable lung allografts for transplantation. One of the proposed strategies to increase the lung donor pool is the use of donors after circulatory-determination-of-death (DCD), which has the potential to significantly alleviate the shortage of transplantable lungs. According to the Maastricht classification, there are five types of DCD donors. The first two categories are uncontrolled DCD donors (uDCD); the other three are controlled DCD donors (cDCD). Clinical experience with uncontrolled DCD donors is scarce and remains limited to small case series. Controlled DCD donation, meanwhile, is the most accepted type of DCD donation for lungs. Although the DCD donor pool has significantly increased, it is still underutilized worldwide. To achieve a high retrieval rate, experience with DCD donation, adequate management of the potential DCD donor at the intensive care unit (ICU), and expertise in combined organ procurement are critical. This review presents a concise update of lung donation after circulatory-determination-of-death and includes a step-by-step protocol of lung procurement using abdominal normothermic regional perfusion.

Lung transplantation from donation after circulatory death, evolution, and current status in the United States

BACKGROUND

The number of lung transplants from donors after circulatory death has increased over the last decade. This study aimed to describe the evolution and outcomes following lung transplantation donation after circulatory death (DCD) and report the practices and outcomes of ex vivo lung perfusion (EVLP) in this donor population.

METHODS

This was a retrospective study using a prospectively collected national registry. The United Network for Organ Sharing (UNOS) database was queried to identify adult patients who underwent lung transplantation between May 1, 2005, and December 31, 2021. Kaplan-Meier analysis and Weibull regression were used to compare survival in four cohorts (donation after brain death [DBD] with or without EVLP, and DCD with or without EVLP). The primary outcome of interest was patient survival.

RESULTS

Of the 21 356 recipients who underwent lung transplantation, 20 380 (95.4%) were from brain death donors and 976 (4.6%) from donors after circulatory death. Kaplan-Meier analysis showed no difference in the survival time between the two groups. In a multivariable analysis that controlled for baseline differences in donor and recipient characteristics, recipients who received lungs from cardiac death donors after EVLP had 28% shorter survival time relative to donor lungs after brain death without EVLP (hazard ratio [HR] 1.53, 95% confidence interval [CI] 1.10-2.15, p = .01).

CONCLUSIONS

The early survival differences observed after lung transplants from donors after circulatory death in lungs evaluated with EVLP deserves further investigation.

Donation after circulatory death and lung transplantation

Lung transplantation is the most effective modality for the treatment of patients with end-stage lung diseases. Unfortunately, many people cannot benefit from this therapy due to insufficient donor availability. In this review and update article, we discuss donation after circulatory death (DCD), which is undoubtedly essential among the strategies developed to increase the donor pool. However, there are ethical and legislative considerations in the DCD process that are different from those of donation after brain death (DBD). Among others, the critical aspects of DCD are the concept of the end of life, cessation of futile treatments, and withdrawal of life-sustaining therapy. In addition, this review describes a rationale for using lungs from DCD donors and provides some important definitions, highlighting the key differences between DCD and DBD, including physiological aspects pertinent to each category. The unique ability of lungs to maintain cell viability without circulation, assuming that oxygen is supplied to the alveoli-an essential aspect of DCD-is also discussed. Furthermore, an updated review of the clinical experience with DCD for lung transplantation across international centers, recent advances in DCD, and some ethical dilemmas that deserve attention are also reported.

Current status and further potential of lung donation after circulatory death

Chronic organ shortage remains the most limiting factor in lung transplantation. To overcome this shortage, a minority of centers have started with efforts to reintroduce donation after circulatory death (DCD). This review aims to evaluate the experimental background, the current international clinical experience, and the further potential and challenges of the different DCD categories. Successful strategies have been implemented to reduce the problems of warm ischemic time, thrombosis after circulatory arrest, and difficulties in organ assessment, which come with DCD donation. From the currently reported results, controlled-DCD lungs are an effective and safe method with good mid-term and even long-term survival outcomes comparable to donation after brain death (DBD). Primary graft dysfunction and onset of chronic allograft dysfunction seem also comparable. Thus, controlled-DCD lungs should be ceased to be treated as marginal and instead be promoted as an equivalent alternative to DBD. A wide implementation of controlled-DCD-lung donation would significantly decrease the mortality on the waiting list. Therefore, further efforts in establishment of legislation and logistics are crucial. With regard to uncontrolled DCD, more data are needed analyzing long-term outcomes. To help with the detailed assessment and improvement of uncontrolled or otherwise questionable grafts after retrieval, ex-vivo lung perfusion is promising.

Impact of donor time to cardiac arrest in lung donation after circulatory death

OBJECTIVE

Acceptance of lungs from donation after circulatory determination of death has been generally restricted to donors who have cardiac arrest within 60 minutes after withdrawal of life-sustaining therapies. We aimed to determine the effect of the interval between withdrawal of life-sustaining therapies to arrest and recipient outcomes. Second, we aimed to compare outcomes between donation after circulatory determination of death transplants and donation after neurologic determination of death transplants.

METHODS

A single-center, retrospective review was performed analyzing the clinical outcomes of transplant recipients who received donation after circulatory determination of death lungs and those who received donation after neurologic determination of death lungs. Donation after circulatory determination of death cases were then grouped on the basis of the interval between withdrawal of life-sustaining therapies and asystole: 0 to 19 minutes (rapid), 20 to 59 minutes (intermediate), and more than 60 minutes (long). Recipient outcomes from each of these groups were compared.

RESULTS

A total of 180 cases of donation after circulatory determination of death and 1088 cases of donation after neurologic determination of death were reviewed between 2007 and 2017. There were no significant differences in the 2 groups in terms of age, gender, recipient diagnosis, and type of transplant (bilateral vs single). Ex vivo lung perfusion was used in 118 of 180 (65.6%) donation after circulatory determination of death cases and 149 of 1088 (13.7%) donation after neurologic determination of death cases before transplantation. The median survivals of recipients who received donation after circulatory determination of death lungs versus donation after neurologic determination of death lungs were 8.0 and 6.9 years, respectively. Time between withdrawal of life-sustaining therapies and asystole was available for 148 of 180 donors (82.2%) from the donation after circulatory determination of death group. Mean and median time from withdrawal of life-sustaining therapies to asystole were 28.6 minutes and 16 minutes, respectively. Twenty donors required more than 60 minutes to experience cardiac arrest, with the longest duration being 154 minutes before asystole was recorded. Recipients of donation after circulatory determination of death lungs who had cardiac arrest at 0 to 19 minutes (90 donors), 20 to 59 minutes (38 donors), and more than 60 minutes (20 donors) did not demonstrate any significant differences in terms of short- and long-term survivals, primary graft dysfunction 2 and 3, intensive care unit stay, mechanical ventilation days, or total hospital stay.

CONCLUSIONS

Short- and long-term outcomes in recipients who received donation after neurologic determination of death versus donation after circulatory determination of death lungs are similar. Different withdrawals of life-sustaining therapies to arrest intervals were not associated with recipient outcomes. The maximum acceptable duration of this interval has yet to be established.

Lung transplantation from donation after controlled cardiocirculatory death. Systematic review and meta-analysis

BACKGROUND

The interest in donation after cardiocirculatory death (DCD) donors for lung transplantation (LT) has been recently rekindled due to lung allograft shortage. Clinical outcomes following DCD have proved satisfactory. The aim of this systematic review is to provide a thorough analysis of published experience regarding outcomes of LT after controlled DCD compared with donation after brain death (DBD) donors.

METHODS

We performed a literature search in Cochrane Database of Systematic Reviews, PubMed and Web of Science using the items "lung transplantation" AND "donation after circulatory death" on November 1, 2018. The full text of relevant articles was evaluated by two authors independently. Quality assessment was performed using the NIH protocol for case-control and case series studies. A pooled Odds ratio (OR) and mean differences with inverse variance weighting using DerSimonian-Laird random effect models were computed to account for between-trial variance (τ2).

RESULTS

Of the 508 articles identified with our search, 9 regarding controlled donation after cardiac death (cDCD) were included in the systematic review, including 2973 patients (403 who received graft from DCD and 2570 who had DBD). Both 1-year survival and 2 and 3-grade primary graft dysfunction (PGD) were balanced between the two cohorts (OR = 1.00 and 1.03 respectively); OR for airway complications was 2.07 against cDCD. We also report an OR = 0.57 for chronic lung allograft dysfunction (CLAD) and an OR = 0.57 for 5-year survival against cDCD.

CONCLUSIONS

Our meta-analysis shows no significant difference between recipients after cDCD or DBD regarding 1-year survival, PGD and 1-year freedom from CLAD. Airway complications and long-term survival were both related with transplantation after cDCD, but these statistical associations need further research.

Use of Lung Allografts From Donation After Cardiac Death Donors: A Single-Center Experience

BACKGROUND

Lung transplantation remains the only treatment for end-stage lung disease. Availability of suitable lungs does not parallel this growing trend. Centers using donation after cardiac death (DCD) donor lungs report comparable outcomes with those from brain-dead donors. Donor assessment protocols and consistent surgical teams have been advocated when considering using the use of DCD donors. We present our experience using lungs from Maastricht category III DCD donors.

METHODS

Starting 2007 to July 2016, 73 DCD donors were assessed, 44 provided suitable lungs that resulted in 46 transplants. A 2012 to October 2016 comparative cohort of 379 brain-dead donors were assessed. Recipient and donor characteristics and primary graft dysfunction (PGD) and survival were monitored.

RESULTS

Seventy-three DCD (40% dry run rate) donors assessed yielded 46 transplants (23 double, 6 right, and 17 left). Comparative cohort of 379 brain-dead donors yielded 237 transplants (112 double, 43 right, and 82 left). One- and 3-year recipient survival was 91% and 78% for recipients of DCD lungs and 91% and 75% for recipients of lungs from brain-dead donors, respectively. PGD 2 and 3 in DCD recipients at 72 hours was 4 of 46 (9%) and 6 of 46 (13%), respectively. Comparatively, brain-dead donor recipient cohort at 72 hours with PGD 2 and 3 was 23 of 237 (10%) and 41 of 237 (17%), respectively.

CONCLUSIONS

Our experience reaffirms the use of lungs from DCD donors as a viable source with favorable outcomes. Recipients from DCD donors showed equivalent PGD rate at 72 hours and survival compared with recipients from brain-dead donors.

A Multicenter Study on Long-Term Outcomes After Lung Transplantation Comparing Donation After Circulatory Death and Donation After Brain Death

The implementation of donation after circulatory death category 3 (DCD3) was one of the attempts to reduce the gap between supply and demand of donor lungs. In the Netherlands, the total number of potential lung donors was greatly increased by the availability of DCD3 lungs in addition to the initial standard use of donation after brain death (DBD) lungs. From the three lung transplant centers in the Netherlands, 130 DCD3 recipients were one-to-one nearest neighbor propensity score matched with 130 DBD recipients. The primary end points were primary graft dysfunction (PGD), posttransplant lung function, freedom from chronic lung allograft dysfunction (CLAD), and overall survival. PGD did not differ between the groups. Posttransplant lung function was comparable after bilateral lung transplantation, but seemed worse after DCD3 single lung transplantation. The incidence of CLAD (p = 0.17) nor the freedom from CLAD (p = 0.36) nor the overall survival (p = 0.40) were significantly different between both groups. The presented multicenter results are derived from a national context where one third of the lung transplantations are performed with DCD3 lungs. We conclude that the long-term outcome after lung transplantation with DCD3 donors is similar to that of DBD donors and that DCD3 donation can substantially enlarge 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.

Hydrogen sulfide prevents renal ischemia-reperfusion injury in CLAWN miniature swine

BACKGROUND

Hydrogen sulfide (H₂S) has recently been reported to demonstrate both antiinflammatory and cytoprotective effects; however, its efficacy has not been well documented in large animal models. In this study, we examined whether the administration of H₂S offers cytoprotective effects on renal ischemia-reperfusion injury (IRI) in a preclinical miniature swine model.

METHODS

Major histocompatibility complex-inbred, CLAWN miniature swine (n = 9) underwent a right nephrectomy, followed by induction of a 120-min period of warm ischemia via placement of clamps on the left renal artery and vein. Group 1 (n = 3) underwent renal ischemia without H₂S administration. Groups 2 (n = 3) and 3 (n = 3) received Na₂S (prodrug of H₂S) 10 min before reperfusion of the ischemic kidneys followed by a 30-min of Na₂S postreperfusion intravenously (group 2) or selective administration of Na₂S via the left renal artery (group 3). IRI was assessed by kidney biopsies, levels of inflammatory cytokines in sera and kidney tissue.

RESULTS

Animals in group 1 had significantly higher serum creatinine levels compared with animals in groups 2 and 3 (P < 0.01). Histology showed severe tubular damage with TUNEL-positive cells in group 1 on postoperative day 2 compared with mild damage in group 2 and minimal damage in group 3. Furthermore, levels of inflammatory cytokines in both serum (interleukin-6 [IL-6], tumor necrosis factor-α, and high-mobility group box 1) and renal tissue (IL-1 and IL-6) in group 3 were markedly lower than in group 2, suggesting beneficial effects of selective Na₂S administration.

CONCLUSIONS

Na₂S administration, especially via an organ selective approach, appears to potentially offer cytoprotective and antiinflammatory effects following renal IRI.

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.

Lung Quality and Utilization in Controlled Donation After Circulatory Determination of Death Within the United States

Although controlled donation after circulatory determination of death (cDCDD) could increase the supply of donor lungs within the United States, the yield of lungs from cDCDD donors remains low compared with donation after neurologic determination of death (DNDD). To explore the reason for low lung yield from cDCDD donors, Scientific Registry of Transplant Recipient data were used to assess the impact of donor lung quality on cDCDD lung utilization by fitting a logistic regression model. The relationship between center volume and cDCDD use was assessed, and the distance between center and donor hospital was calculated by cDCDD status. Recipient survival was compared using a multivariable Cox regression model. Lung utilization was 2.1% for cDCDD donors and 21.4% for DNDD donors. Being a cDCDD donor decreased lung donation (adjusted odds ratio 0.101, 95% confidence interval [CI] 0.085-0.120). A minority of centers have performed cDCDD transplant, with higher volume centers generally performing more cDCDD transplants. There was no difference in center-to-donor distance or recipient survival (adjusted hazard ratio 1.03, 95% CI 0.78-1.37) between cDCDD and DNDD transplants. cDCDD lungs are underutilized compared with DNDD lungs after adjusting for lung quality. Increasing transplant center expertise and commitment to cDCDD lung procurement is needed to improve utilization.

Controlled non-heart beating donor lung transplantation: initial experience in Spain

Although the number of lung transplants in Spain is increasing annually, more organs are required to ease waiting lists. Controlled non-heart beating donors (NHBD) (Maastricht III) are a reality at international level, and contribute significantly to increasing donor numbers. In this study, we present our NHBD protocol and the initial experience in Spain using lung grafts from this type of donor. Three bilateral lung transplants were performed between January 2012 and December 2014. Preservation was by ex-vivo lung perfusion in 2 cases and by traditional cold ischemia in the other. None of the patients developed grade 3 primary graft dysfunction, no in-hospital mortality was recorded and 1-year survival was 100%. These initial results, and international experience, should help to develop similar protocols to encourage the use of controlled non-heart beating donors.

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.

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.

Long-term results after lung transplantation using organs from circulatory death donors: a propensity score-matched analysis†

OBJECTIVES

Due to organ shortage in lung transplantation (LTx), donation after circulatory death (DCD) has been implemented in several countries, contributing to an increasing number of organs transplanted. We sought to assess long-term outcomes after LTx with organs procured following circulatory death in comparison with those obtained from donors after brain death (DBD).

METHODS

Between January 2007 and November 2013, 302 LTxs were performed in our institution, whereby 60 (19.9%) organs were retrieved from DCD donors. We performed propensity score matching (DCD:DBD = 1:2) based on preoperative donor and recipient factors that were significantly different in univariate analysis.

RESULTS

After propensity matching, there were no statistically significant differences between the groups in terms of demographics and preoperative donor and recipient characteristics. There were no significant differences regarding intraoperative variables and total ischaemic time. Patients from the DCD group had significantly higher incidence of primary graft dysfunction grade 3 at the end of the procedure (P = 0.014), and significantly lower pO2/FiO2 ratio during the first 24 h after the procedure (P = 0.018). There was a trend towards higher incidence of the need for postoperative extracorporeal life support in the DCD group. Other postoperative characteristics were comparable. While the overall cumulative survival was not significantly different, the DCD group had significantly poorer results in terms of bronchiolitis obliterans syndrome (BOS)-free survival in the long-term follow-up.

CONCLUSIONS

Long-term results after LTx with organs procured following DCD are in general comparable with those obtained after DBD LTx. However, patients transplanted using organs from DCD donors have a predisposition for development of BOS in the longer follow-up.

Lung transplantation in chronic obstructive pulmonary disease: long-term survival, freedom from bronchiolitis obliterans syndrome, and factors influencing outcome

OBJECTIVES

Lung transplantation (LTx) remains the definitive treatment for end-stage lung failure, whereas chronic obstructive pulmonary disease (COPD) represents one of the main diagnoses leading to the indication for a transplant. We sought to assess long-term outcomes after LTx in patients diagnosed with COPD and analyze factors influencing outcome in this frequent patient cohort.

METHODS

Between January 2007 and November 2013, a total of 88 LTx were performed in patients with COPD in our institution. Patients with emphysema associated with alpha1-antitrypsin deficiency were excluded from this observation. The study design was a retrospective review of the prospectively collected data. A large number of pre-, intra-, and postoperative variables were analyzed including long-term survival and freedom from bronchiolitis obliterans syndrome (BOS). Furthermore, impact of different variables on survival was analyzed.

RESULTS

Preoperative donor data indicated a large proportion of marginal donors. While the overall cumulative survival after six yr was 57.4%, the results in terms of BOS-free survival in long-term follow-up were 39.7% after six yr. Patients with COPD were also associated with a low incidence (2.3%) of the need for postoperative extracorporeal life support (ECLS).

CONCLUSIONS

Long-term results after LTx in patients with COPD are acceptable with excellent survival, freedom from BOS, and low use of ECLS postoperatively despite permanently increasing proportion of marginal organs used.

Lung transplantation from donation after cardiocirculatory death: a systematic review and meta-analysis

BACKGROUND

Lung transplantation (LTx) can extend life expectancy and enhance the quality of life for select patients with end-stage lung disease. In the setting of donor lung shortage and waiting list mortality, the interest in donation after cardiocirculatory death (DCD) is increasing. We performed a systematic review and meta-analysis to compare outcomes between DCD and conventional donation after brain death (DBD).

METHODS

PubMed, CINAHL, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and ClinicalTrials.gov were searched. We identified original research studies with 1-year post-transplant survival data involving >5 DCD transplants. We performed meta-analyses examining 1-year survival, primary graft dysfunction, and acute rejection after LTx.

RESULTS

We identified 519 citations; 11 observational cohort studies met our inclusion criteria for systematic review, and 6 met our inclusion criteria for meta-analysis. There were no differences found in 1-year mortality after LTx between DCD and DBD cohorts in individual studies or in the meta-analysis (DCD [n = 271] vs DBD [n = 2,369], relative risk [RR] 0.88, 95% confidence interval [CI] 0.59-1.31, p = 0.52, I(2) = 0%). There was also no difference between DCD and DBD in a pooled analysis of 5 studies reporting on primary graft dysfunction (RR 1.09, 95% CI 0.68-1.73, p = 0.7, I(2) = 0%) and 4 studies reporting on acute rejection (RR 0.72, 95% CI 0.49-1.05, p = 0.09, I(2) = 0%).

CONCLUSIONS

Survival after LTx from DCD is comparable to survival after LTx from DBD in observational cohort studies. DCD appears to be a safe and effective method to expand the donor pool.

Lung transplantation from donors after circulatory death using portable ex vivo lung perfusion

BACKGROUND

Donation after circulatory death is a novel method of increasing the number of donor lungs available for transplantation. Using organs from donors after circulatory death has the potential to increase the number of transplants performed.

METHODS

Three bilateral lung transplants from donors after circulatory death were performed over a six-month period. Following organ retrieval, all sets of lungs were placed on a portable ex vivo lung perfusion device for evaluation and preservation.

RESULTS

Lung function remained stable during portable ex vivo perfusion, with improvement in partial pressure of oxygen/fraction of inspired oxygen ratios. Mechanical ventilation was discontinued within 48 h for each recipient and no patient stayed in the intensive care unit longer than eight days. There was no postgraft dysfunction at 72 h in two of the three recipients. Ninety-day mortality for all recipients was 0% and all maintain excellent forced expiratory volume in 1 s and forced vital capacity values post-transplantation.

CONCLUSION

The authors report excellent results with their initial experience using donors after circulatory death after portable ex vivo lung perfusion. It is hoped this will allow for the most efficient use of available donor lungs, leading to more transplants and fewer deaths for potential recipients on wait lists.

Utilization of the Organ Care System Lung for the assessment of lungs from a donor after cardiac death (DCD) before bilateral transplantation

In this manuscript, we present the first experience of evaluating donation after circulatory death (DCD) lungs, using the normothermic preservation Organ Care System (OCS) and subsequent successful transplantation. The OCS could be a useful tool for the evaluation of marginal lungs from DCD donors as it allows a proper recruitment and bronchoscopy in such donations in addition to continuous ex-vivo perfusion and assessment and treatment during transport. The OCS could potentially be a standard of care in the evaluation of marginal lungs from DCD.

Mesenchymal stem cell pretreatment of non-heart-beating-donors in experimental lung transplantation

Background

Lung transplantation (LTx) is still limited by organ shortage. To expand the donor pool, lung retrieval from non-heart-beating donors (NHBD) was introduced into clinical practice recently. However, primary graft dysfunction with inactivation of endogenous surfactant due to ischemia/reperfusion-injury is a major cause of early mortality. Furthermore, donor-derived human mesenchymal stem cell (hMSC) expansion and fibrotic differentiation in the allograft results in bronchiolitis obliterans syndrome (BOS), a leading cause of post-LTx long-term mortality. Therefore, pretreatment of NHBD with recipient-specific bone-marrow-(BM)-derived hMSC might have the potential to both improve the postischemic allograft function and influence the long-term development of BOS by the numerous paracrine, immunomodulating and tissue-remodeling properties especially on type-II-pneumocytes of hMSC.

Methods

Asystolic pigs (n = 5/group) were ventilated for 3 h of warm ischemia (groups 2–4). 50x106 mesenchymal-stem-cells (MSC) were administered in the pulmonary artery (group 3) or nebulized endobronchially (group 4) before lung preservation. Following left-lung-transplantation, grafts were reperfused, pulmonary-vascular-resistance (PVR), oxygenation and dynamic-lung-compliance (DLC) were monitored and compared to control-lungs (group 2) and sham-controls (group 1). To prove and localize hMSC in the lung, cryosections were counter-stained. Intra-alveolar edema was determined stereologically. Statistics comprised ANOVA with repeated measurements.

Results

Oxygenation (p = 0.001) and PVR (p = 0.009) following endovascular application of hMSC were significantly inferior compared to Sham controls, whereas DLC was significantly higher in endobronchially pretreated lungs (p = 0.045) with overall sham-comparable outcome regarding oxygenation and PVR. Stereology revealed low intrapulmonary edema in all groups (p > 0.05). In cryosections of both unreperfused and reperfused grafts, hMSC were localized in vessels of alveolar septa (endovascular application) and alveolar lumen (endobronchial application), respectively.

Conclusions

Preischemic deposition of hMSC in donor lungs is feasible and effective, and endobronchial application is associated with significantly better DLC as compared to sham controls. In contrast, transvascular hMSC delivery results in inferior oxygenation and PVR. In the long term perspective, due to immunomodulatory, paracrine and tissue-remodeling effects on epithelial and endothelial restitution, an endobronchial NHBD allograft-pretreatment with autologous mesenchymal-stem-cells to attenuate limiting bronchiolitis-obliterans-syndrome in the long-term perspective might be promising in clinical lung transplantation. Subsequent work with chronic experiments is initiated to further elucidate this important field.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-014-0151-3) contains supplementary material, which is available to authorized users.

Recovery of donor hearts after circulatory death with normothermic extracorporeal machine perfusion

OBJECTIVES

A severe donor organ shortage leads to the death of a substantial number of patients who are listed for transplantation. The use of hearts from donors after circulatory death could significantly expand the donor organ pool, but due to concerns about their viability, these are currently not used for transplantation. We propose short-term ex vivo normothermic machine perfusion (MP) to improve the viability of these ischaemic donor hearts.

METHODS

Hearts from male Lewis rats were subjected to 25 min of global in situ warm ischaemia (WI) (37°C), explanted, reconditioned for 60 min with normothermic (37°C) MP with diluted autologous blood and then stored for 4 h at 0-4°C in Custodiol cold preservation solution. Fresh and ischaemic hearts stored for 4 h in Custodiol were used as controls. Graft function was assessed in a blood-perfused Langendorff circuit.

RESULTS

During reconditioning, both the electrical activity and contractility of the ischaemic hearts recovered rapidly. Throughout the Langendorff reperfusion, the reconditioned ischaemic hearts had a higher average heart rate and better contractility compared with untreated ischaemic controls. Moreover, the reconditioned ischaemic hearts had higher tissue adenosine triphosphate levels and a trend towards improved tissue redox state. Perfusate levels of troponin T, creatine kinase and lactate dehydrogenase were not significantly lower than those of untreated ischaemic controls. The micro- and macroscopic appearance of the reconditioned ischaemic hearts were improved compared with ischaemic controls, but in both groups myocardial damage and oedema were evident.

CONCLUSIONS

Our results indicate that functional recovery from global WI is possible during short-term ex vivo reperfusion, allowing subsequent cold storage without compromising organ viability. We expect that once refined and validated, this approach may enable safe transplantation of hearts obtained from donation after circulatory death.

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.

Retrograde flush is more protective than heparin in the uncontrolled donation after circulatory death lung donor

BACKGROUND

Formation of microthrombi after circulatory arrest is a concern for the development of reperfusion injury in lung recipients from donation after circulatory death (DCD) donors. In this isolated lung reperfusion study, we compared the effect of postmortem heparinization with preharvest retrograde pulmonary flush or both.

METHODS

Domestic pigs (n = 6/group) were sacrificed by ventricular fibrillation and left at room temperature for 1 h. This was followed by 2.5 h of topical cooling. In control group [C], no heparin and no pulmonary flush were administered. In group [R], lungs were flushed with Perfadex in a retrograde way before explantation. In group [H], heparin (300 IU/kg) was administered 10 min after cardiac arrest followed by closed chest massage for 2 min. In the combined group, animals were heparinized and the lungs were explanted after retrograde flush [HR]. The left lung was assessed for 60 min in an ex vivo reperfusion model.

RESULTS

Pulmonary vascular resistance at 50 and 55 min was significantly lower in [R] and [HR] groups compared with [C] and [H] groups (P < 0.01 and P < 0.001) and at 60 min in [R], [H], and [HR] groups compared with [C] group (P < 0.001). Oxygenation, compliance, and plateau airway pressure were more stable in [R] and [HR] groups. Plateau airway pressure was significantly lower in [R] group compared with the [H] group at 60 min (P < 0.05). No significant differences in wet-dry weight ratio were observed between the groups.

CONCLUSIONS

This study suggests that preharvest retrograde flush is more protective than postmortem heparinization to prevent reperfusion injury in lungs recovered from donation after circulatory death donors.

Initial topical cooling followed by backtable Celsior flush perfusion provides excellent early graft function in porcine single lung transplantation after 24 hours of cold ischemia

BACKGROUND

Topical in situ cooling of the donor lungs is a prerequisite for procurement of non-heart-beating donor lungs and may be of interest for living related lung donation.

METHODS

Twenty-four single lung transplants were performed in 4 groups of Landrace pigs (6 per group). Control LPD, control Celsior and topical cooling in situ, followed by LPD (exLPD) or Celsior (exCel) ex situ flush, were employed. All lungs were perfused antegrade with 1 liter of solution at 4°C. Lungs were stored immersed in preservation solution for 24 hours at 4°C. After transplantation of the left lung, the right recipient bronchus and pulmonary artery were clamped.

RESULTS

Four of 6 animals each in the LPD and Celsior groups and all 6 animals in both the exLPD and the exCel groups survived the 7-hour reperfusion. The mean oxygenation index was favorably preserved in the exCel group at 7 hours after reperfusion (417 ± 81) over all other groups (LPD 341 ± 133, Celsior 387 ± 86, exLPD 327 ± 76; p < 0.0001). Pulmonary vascular resistance showed significantly lower values in the Celsior and exCel groups (LPD 1,310 ± 620, Celsior 584 ± 194, exLPD 1,035 ± 361, exCel 650 ± 116 dyn/s/cm(5) at 7 hours after reperfusion; p < 0.0001). Consistently, the wet-to-dry lung weight ratio also indicated beneficial graft protection in the exCel group (LPD 8.1 ± 0.8, Celsior 8.4 ± 0.8, exLPD 7.5 ± 1.0, exCel 3.1 ± 0.9; p < 0.0001).

CONCLUSION

Initial topical cooling followed by backtable perfusion is a sufficient technique for pulmonary graft preservation providing excellent post-transplant function. Celsior subsequent to in-situ topical cooling revealed the most beneficial results in this setting. This combined technique could advance non-heart-beating, living related lung lobe donation and, potentially, regular heart-beating lung donation.

Sequential improvements in organ procurement increase the organ donation rate

PURPOSE

Organ demand exceeds availability of transplantable organs. Organ procurement continues to suffer from failures to identify potential donors, inability to obtain consent for donation, as well as failures to retrieve certain organs as donor demographics change. The purpose of this article is to propose how sequentially introduced measures can increase organ donation rates as well as improve organ procurement.

METHODS

We analysed the effect of stepwise improvements in the organ procurement process patients in a university-based surgical intensive care unit over a 20-year period. We related newly introduced measures in the organ retrieval process with changes in donation rates. We specifically targeted these three main steps in the donation process: donor identification, conversion of potential donors to actual donors, and organ protection during the procurement process. Finally, we assessed the effect of the same measures on organ procurement after introduction in other hospitals of the same organ procurement region.

RESULTS

Introduction of quality improvement steps increased all of the observed parameters. The number of organ donors was stabilised due to a better identification of potential donors, a major increase in conversion from potential to actual donors, and an increase in extended criteria donor. Improvements in organ protection led to higher rates of organs transplanted per donor and increased recovery of lungs and hearts despite increasing donor age. The same measures were introduced successfully in other hospitals in our organ procurement region.

CONCLUSION

Sequential improvements in organ procurement can increase the yield of retrieved organs. The same measures can be applied to other hospitals and lead to comparable improvements in organ donation.

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.

Lungs from donation after circulatory death donors: an alternative source to brain-dead donors? Midterm results at a single institution

OBJECTIVES

Donor organ shortage remains to be the major limitation in lung transplantation, and donation after circulatory death (DCD) might represent one way to alleviate this problem. DCD was introduced to our institution in 2007 and has been a part of our clinical routine since then. Here, we present the mid-term results of lung transplantation from DCD in a single institution and compare the outcomes with the lung recipient cohort receiving lungs from donation after brain death (DBD).

METHODS

Since initiation of the DCD programme in March 2007, of the 157 lung transplantations performed, 26 (16.5%) were retrieved from DCD donors, with 25 double- and 1 single-lung transplants being performed. Results were compared with standard DBD transplantations. Analyses included, amongst others, donor characteristics, survival, prevalence of primary graft dysfunction, acute rejection, lung function tests during follow-up, onset of bronchiolitis obliterans syndrome (BOS) as well as duration of mechanical ventilation, hospital and intensive care unit length of stay.

RESULTS

While there was no significant difference between lung function, BOS and survival between the two groups, lungs from DCD donors had a higher PaO(2) (median; interquartile range) 498.3 (451.5; 525) vs. DBD 442.5 (371.25; 502) kPa before retrieval (P = 0.009). There was also a longer total ischaemic time in the DCD vs. DBD group: 320 min (298.75; 393.25) vs. 285.5 min (240; 373) (P = 0.025). All other parameters were comparable.

CONCLUSIONS

Medium-term results after lung transplantation with organs procured after circulatory death are comparable with those obtained after standard lung transplantation. Therefore, DCD could be used to significantly increase the donor pool.

Donation after cardiac death lung transplantation outcomes

PURPOSE OF REVIEW

Lung transplantation is now a well established treatment option for several end-stage respiratory diseases. Survival after lung transplantation has significantly improved over the last decade. The primary limitation to increased utilization of lung transplantation remains donor scarcity. Suitable allografts have been procured from donors after determination of neurologic death and from donors after determination of cardiac death (DDCD or DCD). Historically, the first human lung transplantation performed, utilized an allograft procured after cardiovascular death, also referred to as nonheart-beating donor.The experience at University of Wisconsin in 1993 reintroduced DCD lung transplantation with the first successful clinical case.

RECENT FINDINGS

A potential additional lung allograft source, DCD lung transplantation has been established with very acceptable outcomes observed by several centers. We provide the relevant background for the rationale of donor allograft expansion to include DCD lungs from controlled (Maastricht category III donors).

SUMMARY

This review considers the available evidence for DCD lung transplantation and compares reported primary graft dysfunction rates and current survival data available.