Recommendations for the use of extended criteria donors in lung transplantation

Effect of hypertonic saline in the pretreatment of lung donors with hemorrhagic shock

BACKGROUND

Hemorrhagic shock-induced lung edema and inflammation are two of the main reasons for the rejection of lungs donated for transplantation. Hypertonic saline (HS) induces intravascular volume expansion and has considerable immunomodulating effects that might minimize edema. Our hypothesis is based on the use of a hypertonic solution for treatment of donors who are in shock in an attempt to increase the supply of lungs for transplantation.

METHODS

A total of 80 rats were allocated to four groups: one group was given an infusion of normal saline (NS; n = 20), one group received HS; n = 20, a sham group (n = 20), and a Shock group (n = 20). Half of the lungs from each group were evaluated in an ex vivo perfusion system, and the other half was used for measurements of cytokine levels and neutrophil counts.

RESULTS

In the ex vivo perfusion assessment, the pulmonary artery pressures of the animals in the NS and HS groups did not exhibit significant differences compared with those in the sham group (P > 0.05) but were lower than those in the Shock group (P < 0.01). Furthermore, the tumor necrosis factor-α levels and neutrophil counts were lower in the HS group than those in the Shock group (P < 0.01) and did not exhibit significant differences compared with those in either the NS and Sham groups (P > 0.05).

CONCLUSIONS

We showed that HS was equivalent to isotonic saline and contributed to the treatment of lungs subjected to hemorrhagic shock.

Engineering a microcirculation for perfusion control of ex vivo-assembled organ systems: Challenges and opportunities

Donor organ shortage remains a clear problem for many end-stage organ patients around the world. The number of available donor organs pales in comparison with the number of patients in need of these organs. The field of tissue engineering proposes a plausible solution. Using stem cells, a patient's autologous cells, or allografted cells to seed-engineered scaffolds, tissue-engineered constructs can effectively supplement the donor pool and bypass other problems that arise when using donor organs, such as who receives the organ first and whether donor organ rejection may occur. However, current research methods and technologies have been unable to successfully engineer and vascularize large volume tissue constructs. This review examines the current perfusion methods for ex vivo organ systems, defines the different types of vascularization in organs, explores various strategies to vascularize ex vivo organ systems, and discusses challenges and opportunities for the field of tissue engineering.

The association of donor age and survival is independent of ischemic time following deceased donor lung transplantation

PURPOSE

Early research suggests prolonged ischemic time in older donor lungs is associated with decreased survival following lung transplantation. The purpose of this study was to determine whether this association holds in the post-lung allocation score era.

METHODS

We analyzed the United Network for Organ Sharing database 2005-2013 for adult recipients of cadaveric lung transplants. Cox proportional hazards modeling was utilized to determine the association of donor age, ischemic time, and the interaction of donor age and ischemic time with transplant-free survival.

RESULTS

Eleven thousand eight hundred thirty-five patients met criteria. Median donor age was 32 years, and median ischemic time was 4.9 hours. Cox modeling demonstrated that donor age 50-60 (adjusted hazard ratio (HR): 1.11) and ≥60 (adjusted HR: 1.42) were associated with reduced overall survival. Neither ischemic time nor interaction of ischemic time and donor age were significantly associated with overall survival. Subanalysis demonstrated that this finding held true for patients undergoing either single or bilateral lung transplantation.

CONCLUSIONS

Prolonged ischemic time is not associated with decreased overall survival in patients undergoing lung transplantation regardless of the donor's age. However, donor age >50 is independently associated with decreased survival. The lack of an association between ischemic time and survival should encourage broader geographic allocation of pulmonary allografts.

Guidelines for the assessment and acceptance of potential brain-dead organ donors

Organ transplantation is the only alternative for many patients with terminal diseases. The increasing disproportion between the high demand for organ transplants and the low rate of transplants actually performed is worrisome. Some of the causes of this disproportion are errors in the identification of potential organ donors and in the determination of contraindications by the attending staff. Therefore, the aim of the present document is to provide guidelines for intensive care multi-professional staffs for the recognition, assessment and acceptance of potential organ donors.

Lung transplantation: overall approach regarding its major aspects

Lung transplantation is a well-established treatment for patients with advanced lung disease. The evaluation of a candidate for transplantation is a complex task and involves a multidisciplinary team that follows the patient beyond the postoperative period. Currently, the mean time on the waiting list for lung transplantation in the state of São Paulo, Brazil, is approximately 18 months. For Brazil as a whole, data from the Brazilian Organ Transplant Association show that, in 2014, there were 67 lung transplants and 204 patients on the waiting list for lung transplantation. Lung transplantation is most often indicated in cases of COPD, cystic fibrosis, interstitial lung disease, non-cystic fibrosis bronchiectasis, and pulmonary hypertension. This comprehensive review aimed to address the major aspects of lung transplantation: indications, contraindications, evaluation of transplant candidates, evaluation of donor candidates, management of transplant recipients, and major complications. To that end, we based our research on the International Society for Heart and Lung Transplantation guidelines and on the protocols used by our Lung Transplant Group in the city of São Paulo, Brazil.

Starting a lung transplant program: a roadmap for long-term excellence

Lung transplantation is an effective therapy for many patients with end-stage lung disease. Few centers across the United States offer this therapy, as a successful lung transplant program requires significant institutional resources and specialized personnel. Analysis of the United Network of Organ Sharing database reveals that the failure rate of new programs exceeds 40%. These data suggest that an accurate assessment of program viability as well as a strategy to continuously assess defined quality measures is needed. As part of strategic planning, regional availability of recipient and donors should be assessed. Additionally, analysis of institutional expertise at the physician, support staff, financial, and administrative levels is necessary. In May of 2007, we started a new lung transplant program at the University of Iowa Hospitals and Clinics and have performed 101 transplants with an average recipient 1-year survival of 91%, placing our program among the top in the country for the past 5 years. Herein, we review internal and external factors that impact the viability of a new lung transplant program. We discuss the use of four prospectively identified quality measures: volume, recipient outcomes, financial solvency, and academic contribution as one approach to achieve programmatic excellence.

Lung transplantation: a treatment option in end-stage lung disease

BACKGROUND

Lung transplantation is the final treatment option in the end stage of certain lung diseases, once all possible conservative treatments have been exhausted. Depending on the indication for which lung transplantation is performed, it can improve the patient's quality of life (e.g., in emphysema) and/ or prolong life expectancy (e.g., in cystic fibrosis, pulmonary fibrosis, and pulmonary arterial hypertension). The main selection criteria for transplant candidates, aside from the underlying pulmonary or cardiopulmonary disease, are age, degree of mobility, nutritional and muscular condition, and concurrent extrapulmonary disease. The pool of willing organ donors is shrinking, and every sixth candidate for lung transplantation now dies while on the waiting list.

METHOD

We reviewed pertinent articles (up to October 2013) retrieved by a selective search in Medline and other German and international databases, including those of the International Society for Heart and Lung Transplantation (ISHLT), Eurotransplant, the German Institute for Applied Quality Promotion and Research in Health-Care (Institut für angewandte Qualitätsförderung und Forschung im Gesundheitswesen, AQUA-Institut), and the German Foundation for Organ Transplantation (Deutsche Stiftung Organtransplantation, DSO).

RESULTS

The short- and long-term results have markedly improved in recent years: the 1-year survival rate has risen from 70.9% to 82.9%, and the 5-year survival rate from 46.9% to 59.6%. The 90-day mortality is 10.0%. The postoperative complications include acute (3.4%) and chronic (29.0%) transplant rejection, infections (38.0%), transplant failure (24.7%), airway complications (15.0%), malignant tumors (15.0%), cardiovascular events (10.9%), and other secondary extrapulmonary diseases (29.8%). Bilateral lung transplantation is superior to unilateral transplantation (5-year survival rate 57.3% versus 47.4%).

CONCLUSION

Seamless integration of the various components of treatment will be essential for further improvements in outcome. In particular, the follow-up care of transplant recipients should always be provided in close cooperation with the transplant center.

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.

Single-lung transplantation in the United States: what happens to the other lung?

BACKGROUND

This study assessed treatment patterns and examined organ utilization in the setting of single-lung transplantation (SLT).

METHODS

The United Network for Organ Sharing database was queried for all SLTs performed from 1987 to 2011. Trends in utilization of the second donor lung were assessed, both from recipient and donor perspectives. Donors were stratified into 2 groups: those donating both lungs and those donating only 1 lung. Independent predictors of using only 1 donor lung were identified using multivariable logistic regression.

RESULTS

We identified 10,361 SLTs originating from 7,232 unique donors. Of these donors, both lungs were used in only 3,129 (43.3%), resulting in more than 200 second donor lungs going unused annually since 2005, with no significant increase in use over time (p = 0.95). After adjustment, donor characteristics predicting the second donor lung going unused included B/AB blood groups (adjusted odds ratio [AOR]: 1.69 and 2.62, respectively; p < 0.001), smaller body surface area (AOR, 1.30; p = 0.02), lower donor partial pressure of arterial oxygen (AOR, 0.90 per 50 mm Hg increase; p < 0.001), pulmonary infection (AOR, 1.15; p = 0.04), extended criteria donor status (AOR, 1.66; p < 0.001), and death caused by head trauma (AOR, 1.57; p < 0.001) or anoxia (AOR, 1.53; p = 0.001).

CONCLUSIONS

Among donors for SLT, less than half of all cases led to use of the second donor lung. Although anatomic, infectious, or other pathophysiologic issues prohibit 100% utilization, more aggressive donor matching efforts may be a simple method of increasing the utilization of this scarce resource, particularly for less common blood types.

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).

Ex vivo lung reconditioning: a new era for lung transplantation

Lung transplantation has come to be viewed as the best treatment option for various end-stage lung diseases. The low number of viable donors continues to be a major obstacle to increasing the number of lung transplants, resulting in high mortality among patients on the waiting list. Unlike transplantation of other solid organs, lung transplantation is primarily limited not by the absolute number of donors but by the viability of the donor lungs, which can be damaged by brain death and by treatments given in the ICU. There are various proposals of ways to increase the number of lung donors: intensification of donation campaigns, use of non-heart-beating donors, living lobar lung transplantation, and adoption of more flexible criteria for donors. However, the proposal that has attracted the most attention from lung transplant groups is ex vivo lung perfusion, especially due to the prospect of reconditioning previously discarded lungs. This system consists of perfusion and ventilation of the isolated heart-lung block using a modified cardiopulmonary bypass circuit. Various authors have been studying this technique due to the satisfactory results obtained and the prospect of an increase in the number of organs suitable for transplantation. Researchers in Sweden, Canada, Austria, England, Spain, and Brazil have extensive experience with the method and have introduced modifications to it. The objective of this article was to review the development of, state of the art in, and future prospects for the ex vivo model of lung perfusion and reconditioning.

Histologic effects of University of Wisconsin two-layer method preservation of rat pancreas

Marginal donors represent a poorly utilized source of organs for transplantation despite their availability. The key is to reduce the ischemic damage in the effort to improve organ quality. This study investigated the histologic effects after in situ perfusion of preservation with a two-layer method compared with the classic University of Wisconsin preservation in term of tissue integrity and number of viable exocrine cells in the rat pancreas both after exsanguination and at 8 weeks of cryopreservation. Pancreata harvested from 60 rats were collected using 3 methods: two-layer method following University of Wisconsin perfusion; exsanguination; and classic University of Wisconsin perfusion/storage. In addition to histologic analysis of collected pancreata, we analyzed the number of CK19(+) cells and their viability using chi-square tests with values P < .05 considered to be significant. Rat pancreas histology showed as University of Wisconsin in situ perfusion and preservation by the two-layer method to be more effective to maintain the morphologic integrity of both exocrine and endocrine tissues. There were a larger number of CK19(+) cells with good viability. Moreover, the effects of oxygenation were visible in pancreas biopsies preserved after exsanguination. In situ University of Wisconsin perfusion and preservation for 240 minutes with the two-layer method yielded greater numbers and viability of CK19(+) cells even after 8 weeks of cryopreservation.

Guidelines for maintenance of adult patients with brain death and potential for multiple organ donations: the Task Force of the Brazilian Association of Intensive Medicine the Brazilian Association of Organs Transplantation, and the Transplantation Center of Santa Catarina

INTRODUCTION

The organ shortage for transplantation, the principal factor that increases waiting lists, has become a serious public health problem. In this scenario, the intensivist occupies a prominent position as one of the professionals that first has a chance to identify brain death and to be responsible for the maintenance of the potential deceased donor.

OBJECTIVE

This report attempts to establish guidelines for care and maintenance of adult deceased donor organs guiding and standardizing care provided to patients with brain death.

METHOD

These guidelines were composed by intensivists, transplant coordinators, professionals from various transplant teams, and used transplant center. The formulated questions were forwarded to all members and recommendations were constructed after an extensive literature review selecting articles with the highest degree of evidence.

RESULTS

Guidelines were developed in the form of questions reflecting frequent experiences in clinical intensive care practices. The main questions were: Is there an optimal interval for keeping organs of deceased donors viable? What actions are considered essential for maintaining deceased donors in this period? What are the limits of body temperature? How should the patient be warmed? Which laboratory tests should be performed? What is the collection interval? What are the limits in the laboratory and the capture scenario? What are the limits of blood pressure? When and how should one use catecholamines?

CONCLUSIONS

This pioneer project involved a multidisciplinary team working in organ transplantation seeking to provide treatment guidance to increase the number of viable organs from deceased adult donors.

Influence of anti-HBc positive organ donor in lung donor selection

INTRODUCTION

The risk of hepatitis B virus (HBV) transmission through donor organs with HBsAg(-) and anti-HBc(+) serology has not been extensively studied in lung transplantation. The objectives of this study are to ascertain the influence of the anti-HBc(+) on the acceptance of the lung for transplantation, to comment on the published literature and to suggest an algorithm for action.

METHODS

A survey conducted in the 7 Spanish lung transplantation teams. The updated search of the literature was performed using medical databases from 1994 to February 2012.

RESULTS

All of the teams vaccinate the lung recipients against HBV, although none quantify the anti-HBs titers. When given an anti-HBc(+) donor, 3 teams change their strategy: one does not accept the offer, one selects the receptor from among patients in emergency status and another adds pharmacological prophylaxis. Only 3 publications refer to the serologic evolution of the receptors. At the moment there have been no reported cases of hepatitis B or HBsAg positivity post-transplant, but 4 out of the 50 anti-HBc(-) receptors changed to anti-HBc(+) in the follow-up.

CONCLUSIONS

The presence of anti-HBc in the donor influences the decision to accept a lung donor, although there is little information on its repercussions. To date, there has been no reported case of transmission of HBV, but post-transplant anti-HBc seroconversions have been described, which suggests contact with viral particles. Although rare, an anti-HBc(+) donor can harbor a hidden HBV infection. The risk of infection can be reduced with adequate anti-HBs titers or with appropriate pharmacological measures.