OPTN/SRTR 2012 Annual Data Report: lung

Lung Transplant Outcomes for Idiopathic Pulmonary Fibrosis: Are We Improving?

BACKGROUND

After implementation of the Lung Allocation Score in 2005, idiopathic pulmonary fibrosis (IPF) emerged as the most common indication for lung transplantation (LT) in the United States. The age and comorbidity of patients undergoing LT have since increased, and the indications for LT have evolved. However, limited data have been used to analyze more recent outcomes among the IPF population.

METHODS

This study analyzed LTs for the primary indication of IPF by using the United Network for Organ Sharing database. An eras-based analysis was performed, comparing patient characteristics, survival, and related outcomes during 2005 to 2009 (era 1) and 2010 to 2014 (era 2) with χ2, Wilcoxon rank sum, and Kaplan-Meier analyses. The study compared 1-year survival from 2005 to 2020 and survival at milestones ranging from 1 month to 5 years. Two adjusted Cox proportional hazards models were conducted: 5-year survival by era and 1-year survival annually from 2010 to 2020.

RESULTS

From era 1 (n = 1818) to era 2 (n = 3227), the median age of LT recipients increased from 61 to 63 years (P < .001). The percentage of patients in the intensive care unit before LT climbed from 7.7% to 12.1% (P < .001), and the percentage of patients with diabetes grew from 17.9% to 19.4% (P = .003). Despite increased severity of illness, 5-year survival increased from 51.9% in era 1 to 55.2% in era 2 (P = .02). Adjusted modeling indicated that LT during era 2 featured a 17% hazard reduction compared with era 1 (hazard ratio, 0.83; 95% CI, 0.76-0.91).

CONCLUSIONS

Survival is improving for patients undergoing LT for IPF, despite the challenges of transplant recipients with progressively higher risk profiles.

Validation of a novel donor lung scoring system based on the updated lung Composite Allocation Score

Lung transplantation (LTx) continues to have lower rates of long-term graft survival compared with other organs. Additionally, lung utilization rates from brain-dead donors remain substantially lower compared with other solid organs, despite a growing need for LTx and the significant risk of waitlist mortality. This study aims to examine the effects of using a combination of the recently described novel lung donor (LUNDON) acceptability score and the newly adopted recipient lung Composite Allocation Score (CAS) to guide transplantation. We performed a review of nearly 18 000 adult primary lung transplants from 2015-2022 across the US with retroactive calculations of the CAS value. The medium-CAS group (29.6-34.5) had superior 1-year posttransplant survival. Importantly, the combination of high-CAS (> 34.5) recipients with low LUNDON score (≤ 40) donors had the worst survival at 1 year compared with any other combination. Additionally, we constructed a model that predicts 1-year and 3-year survival using the LUNDON acceptability score and CAS values. These results suggest that caution should be exercised when using marginally acceptable donor lungs in high-priority recipients. The use of the LUNDON score with CAS value can potentially guide clinical decision-making for optimal donor-recipient matches for LTx.

Advanced Fellowships After Training: Super or Not?

Advanced training in cardiothoracic surgery has become more prevalent in the setting of increased complexity of interventions. Minimally invasive techniques, transcatheter and endovascular interventions, and rapid growth in mechanical circulatory support and transplant have led approximately 40% of trainees to pursue additional training. Available data suggest trainees seek additional training for 3 main reasons: gain an additional skillset, improve candidacy for a job, and/or increase proficiency in basic areas. This review provides an analysis of existing literature, categorized by specialty (cardiac, thoracic, and congenital) to determine areas where additional training is of benefit.

Disturbed sleep after lung transplantation is associated with worse patient-reported outcomes and chronic lung allograft dysfunction

Many lung transplant recipients fail to derive the expected improvements in functioning, HRQL, or long-term survival. Sleep may represent an important, albeit rarely examined, factor influencing lung transplant outcomes. Within a larger cohort study, 141 lung transplant recipients completed the Medical Outcomes Study (MOS) Sleep Scale along with a broader survey of patient-reported outcome (PRO) measures and frailty assessment. MOS Sleep yields the Sleep Problems Index (SPI); we also derived an insomnia-specific subscale. Potential perioperative predictors of disturbed sleep and time to chronic lung allograft dysfunction (CLAD) and death were derived from medical records. We investigated associations between perioperative predictors on SPI and Insomnia and associations between SPI and Insomnia on PROs and frailty by linear regressions, adjusting for age, sex, and lung function. We evaluated the associations between SPI and Insomnia on time to CLAD and death using Cox models, adjusting for age, sex, and transplant indication. Post-transplant hospital length of stay >30 days was associated with worse sleep by SPI and insomnia (SPI: p=0.01; Insomnia p=0.02). Worse sleep by SPI and insomnia was associated with worse depression, cognitive function, HRQL, physical disability, health utilities, and Fried Frailty Phenotype frailty (all p<0.01). Those in the worst quartile of SPI and insomnia exhibited increased risk of CLAD (HR 2.18; 95%CI: 1.22-3.89 ; p=0.01 for SPI and HR 1.96; 95%CI 1.09-3.53; p=0.03 for insomnia). Worsening in SPI but not insomnia was also associated with mortality (HR: 1.29; 95%CI: 1.05-1.58; p=0.01). Poor sleep after lung transplant may be a novel predictor of patient reported outcomes, frailty, CLAD, and death with potentially important screening and treatment implications.

Early experience of a new national lung allocation scheme in the UK based on clinical urgency

INTRODUCTION

A new UK Lung Allocation Scheme (UKLAS) was introduced in 2017, replacing the previous geographic allocation system. Patients are prioritised according to predefined clinical criteria into a three-tier system: the super-urgent lung allocation scheme (SULAS), the urgent lung allocation scheme (ULAS) and the non-urgent lung allocation scheme (NULAS). This study assessed the early impact of this scheme on waiting-list and post-transplant outcomes.

METHODS

A cohort study of adult lung transplant registrations between March 2015 and November 2016 (era-1) and between May 2017 and January 2019 (era-2). Outcomes from registration were compared between eras and stratified by urgency tier and diagnostic group.

RESULTS

During era-1, 461 patients were registered. In era-2, 471 patients were registered (19 (4.0%) SULAS, 82 (17.4%) ULAS and 370 (78.6%) NULAS). SULAS patients were younger (median age 35 vs 50 and 55 for urgent and non-urgent, respectively, p=0.0015) and predominantly suffered from cystic fibrosis (53%) or pulmonary fibrosis (37%). Between eras 1 and 2, the odds of transplantation within 6 months of registration were increased (OR=1.41, 95% CI 1.07 to 1.85, p=0.0142) despite only a 5% increase in transplant activity. Median time-to-transplantation during era-1 was 427 days compared with waiting times in era-2 of 8 days for SULAS, 15 days for ULAS and 585 days for NULAS patients. Waiting-list mortality (15% era-1 vs 13% era-2; p=0.5441) and post-transplant survival at 1 year (81.3% era-1 vs 83.3% era-2; p=0.6065) were similar between eras.

CONCLUSION

The UKLAS scheme prioritises the critically ill and improves transplantation odds. The true impact on waiting-list mortality and post-transplant survival requires further follow-up.

Biometric Profiling to Quantify Lung Injury Through Ex Vivo Lung Perfusion Following Warm Ischemia

Standard physiologic assessment parameters of donor lung grafts may not accurately reflect lung injury or quality. A biometric profile of ischemic injury could be identified as a means to assess the quality of the donor allograft. We sought to identify a biometric profile of lung ischemic injury assessed during ex vivo lung perfusion (EVLP). A rat model of lung donation after circulatory death (DCD) warm ischemic injury with subsequent EVLP evaluation was utilized. We did not observe a significant correlation between the classical physiological assessment parameters and the duration of the ischemic. In the perfusate, solubilized lactate dehydrogenase (LDH) as well as hyaluronic acid (HA) significantly correlated with duration of ischemic injury and length of perfusion ( p < 0.05). Similarly, in perfusates, the endothelin-1 (ET-1) and Big ET-1 correlated ischemic injury ( p < 0.05) and demonstrated a measure of endothelial cell injury. In tissue protein expression, heme oxygenase-1 (HO-1), angiopoietin 1 (Ang-1), and angiopoietin 2 (Ang-2) levels were correlated with the duration of ischemic injury ( p < 0.05). Cleaved caspase-3 levels were significantly elevated at 90 and 120 minutes ( p < 0.05) demonstrating increased apoptosis. A biometric profile of solubilized and tissue protein markers correlated with cell injury is a critical tool to aid in the evaluation of lung transplantation, as accurate evaluation of lung quality is imperative and improved quality leads to better results. http://links.lww.com/ASAIO/B49.

Development and validation of the lung donor (LUNDON) acceptability score for pulmonary transplantation

There is a chronic shortage of donor lungs for pulmonary transplantation due, in part, to low lung utilization rates in the United States. We performed a retrospective cohort study using data from the Scientific Registry of Transplant Recipients database (2006-2019) and developed the lung donor (LUNDON) acceptability score. A total of 83 219 brain-dead donors were included and were randomly divided into derivation (n = 58 314, 70%) and validation (n = 24 905, 30%) cohorts. The overall lung acceptance was 27.3% (n = 22 767). Donor factors associated with the lung acceptance were age, maximum creatinine, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen, mechanism of death by asphyxiation or drowning, history of cigarette use (≥20 pack-years), history of myocardial infarction, chest x-ray appearance, bloodstream infection, and the occurrence of cardiac arrest after brain death. The prediction model had high discriminatory power (C statistic, 0.891; 95% confidence interval, 0.886-0.895) in the validation cohort. We developed a web-based, user-friendly tool (available at https://sites.wustl.edu/lundon) that provides the predicted probability of donor lung acceptance. LUNDON score was also associated with recipient survival in patients with high lung allocation scores. In conclusion, the multivariable LUNDON score uses readily available donor characteristics to reliably predict lung acceptability. Widespread adoption of this model may standardize lung donor evaluation and improve lung utilization rates.

Veno-venous extracorporeal membrane oxygenation for the treatment of respiratory compromise

Extracorporeal membrane oxygenation for the purpose of intervening upon profound cardiovascular or pulmonary compromise has proven to be a worthy intervention. Technological advancements have allowed this mode of therapy to become more effective and widespread. Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is a commonly used strategy to help manage patients with pulmonary dysfunction refractory to traditional management methods. This review intends to focus upon common indications and the clinical considerations for the institution of VV-ECMO as well as some of its known complications.

Anesthetic Management During Lung Transplantation - What's New in 2021?

As outcomes of lung transplantation (LTx) are improving transplant centers are pushing boundaries. There has been a steady increase in the medical complexity of lung transplant candidates. Many transplant centers are listing older patients with comorbidities, and there has been a steady rise in the number of candidates supported with extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation. There has been a growing appreciation of the importance intraoperative management of potentially modifiable risk factors has on postoperative outcomes. Evidence suggests that LTx even in high-risk patients requiring perioperative ECMO can offer excellent results. This article outlines the current state-of-the-art intraoperative management of LTx.

Right Ventricular Assist Device With Extracorporeal Membrane Oxygenation for Bridging Right Ventricular Heart Failure to Lung Transplantation: A Single-Center Case Series and Literature Review

OBJECTIVE

Right ventricular heart failure (RVHF) is a critical complication in patients with respiratory failure, particularly among those who transitioned to lung transplantation using venovenous (VV) extracorporeal membrane oxygenation (ECMO). In these patients, both cardiac and respiratory functions are supported using venoarterial or venoarterial-venous ECMO. However, these modalities increase the risk of device-related complications, such as thromboembolism, bleeding, and limb ischemia, and they may disturb early rehabilitation. Due to these limitations, a right ventricular assist device with an oxygenator (Oxy-RVAD) using ECMO may be considered for patients with RVHF with VV ECMO.

DESIGN

A retrospective case series and literature review.

SETTING

A single tertiary care university hospital.

PARTICIPANTS

The study comprised lung transplantation candidates on ECMO bridging who developed right-sided heart failure.

INTERVENTIONS

An RVAD with ECMO.

MEASUREMENTS AND MAIN RESULTS

Of eight patients who underwent the study protocol, seven were bridged successfully to lung transplantation (BTT), and all patients with BTT were discharged, with a 30-day survival rate of 100% (7/7 patients). The 180-day survival rate was 85% (6/7 patients).

CONCLUSIONS

The study suggested that Oxy-RVAD using ECMO may be a viable option for bridging patients with RVHF to lung transplantation.

TRIAL REGISTRATION

Retrospectively registered.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplant

Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary technology capable of supporting cardiac and respiratory function in the presence of end-stage lung disease. Initial experiences using ECMO as a bridge to lung transplant (ECMO-BTLT) were characterized by high rates of ECMO-associated complications and poor posttransplant outcomes. More recently, ECMO-BTLT has garnered success in preserving patients' physiologic condition and candidacy prior to lung transplant due to technological advances and improved management. Despite recent growth, clinical practice surrounding use of ECMO-BTLT remains variable, with little data to inform optimal patient selection and management. Although many questions remain, the use of ECMO-BTLT has shown promising outcomes suggesting that ECMO-BTLT can be an effective strategy to ensure that complex and rapidly decompensating patients with end-stage lung disease can be safely transplanted with good outcomes. Further studies are needed to refine and inform practice patterns, management, and lung allocation in this high-risk and fragile patient population.

Safe Lung Flush Technique During Recovery From Donors After Circulatory Death

Donation after circulatory death is defined as donation after cardiac arrest and circulatory cessation. The number of circulatory death donors is growing and significantly increases the organ donor pool. Shortening the warm ischemia time is pivotal in the outcomes and survival after transplant. We describe simplified and safe technique for lung flush during lung recovery from donors after circulatory death.

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.

Right ventricular assist device with an oxygenator using extracorporeal membrane oxygenation as a bridge to lung transplantation in a patient with severe respiratory failure and right heart decompensation

Right heart decompensation is a fatal complication in patients with respiratory failure, particularly in those transitioned to lung transplantation using veno-venous extracorporeal membrane oxygenation (V-V ECMO). In these patients, veno-arterial (V-A ECMO) or veno-arterialvenous extracorporeal membrane oxygenation (V-AV ECMO) is used to support both cardiac and respiratory function. However, these processes may increase the risk of device-related complications such as bleeding, thromboembolism, and limb ischemia. In the present case, a 64-year-old male patient with idiopathic pulmonary fibrosis developed respiratory failure and commenced treatment with V-V ECMO as a bridge to lung transplantation. Unfortunately, the patient developed right heart decompensation and required both cardiac and respiratory support during treatment with V-V ECMO. Instead of adding arterial cannulation, he was switched to a novel configuration, a right ventricular assist device with an oxygenator (Oxy- RVAD) using ECMO, with drainage cannulation from the femoral vein and return cannulation to the main pulmonary artery. The patient was successfully bridged to lung transplantation without serious complications after 10 days of Oxy-RVAD support. To the best of our knowledge, this is an extreme rare and challenging case of Oxy-RVAD using ECMO in a patient successfully bridged to lung transplantation.

A novel concept for evaluation of pulmonary function utilizing PaO2/FiO2 difference at the distinctive FiO2 in cellular ex vivo lung perfusion-an experimental study

For more accurate lung evaluation in ex vivo lung perfusion (EVLP), we have devised a new parameter, PaO₂ /FiO₂ ratio difference (PFD); PFD_1-0.4  = P/F ratio at FiO₂ 1.0 - P/F ratio at FiO₂ 0.4. The aim of this study is to compare PFD and transplant suitability, and physiological parameters utilized in cellular EVLP. Thirty-nine human donor lungs were perfused. At 2 h of EVLP, PFD_1-0.4 was compared with transplant suitability and physiological parameters. In a second study, 10 pig lungs were perfused in same fashion. PFD_1-0.4 was calculated by blood from upper and lower lobe pulmonary veins and compared with lobe wet/dry ratio and pathological findings. In human model, receiver operating characteristic curve analysis showed PFD_1-0.4 had the highest area under curve, 0.90, sensitivity, 0.96, to detect nonsuitable lungs, and significant negative correlation with lung weight ratio (R²  = 0.26, P < 0.001). In pig model, PFD_1-0.4 on lower and upper lobe pulmonary veins were significantly associated with corresponding lobe wet/dry ratios (R²  = 0.51, P = 0.019; R²  = 0.37, P = 0.060), respectively. PFD_1-0.4 in EVLP demonstrated a significant correlation with lung weight ratio and allowed more precise assessment of individual lobes in detecting lung edema. Moreover, it might support decision-making in evaluation with current EVLP criteria.

Venous Thromboembolism After Adult Lung Transplantation: A Frequent Event Associated With Lower Survival

BACKGROUND

The incidence of venous thromboembolism (VTE) after lung transplantation (LTX) varies significantly across studies. Two studies have suggested that these thrombotic events are associated with a lower posttransplant survival. Herein, we sought to determine the incidence, predictors, and impact of VTE on survival after LTX at a quaternary referral center.

METHODS

This was a large cohort study of LTX recipients. Key outcome parameters were time to VTE after transplant and survival. Deep vein thrombosis (DVT) diagnosis required a positive ultrasound. Pulmonary embolism diagnosis required either a positive chest computed tomography angiogram or a high-probability ventilation/perfusion scan.

RESULTS

The overall incidence of VTE among 701 LTX recipients was 43.8%, of which 97.7% were DVT episodes, of which 71.3% were in the upper extremities. Predictors of VTE were prior history of DVT (hazard ratio [HR], 2.82; 95% confidence interval [CI], 1.49-5.37), days in intensive care (HR, 1.01; 95% CI, 1.01-1.02), and the use of extracorporeal membrane oxygenation (HR, 2.22; 95% CI, 1.43-3.45). Importantly, VTE predicted a lower posttransplant survival (HR, 1.70; 95% CI, 1.28-2.26), when occurring within or after the first 30 days. The location of the DVT, either upper extremity or below the knee, also predicted a poor survival.

CONCLUSIONS

VTE was frequent in LTX recipients and predicted a poor survival even when located in the upper extremities or below the knee. These data suggest that aggressive VTE screening/treatment protocols be implemented in post-LTX population.

National Heart, Lung, and Blood Institute and American Association for Thoracic Surgery Workshop Report: Identifying collaborative clinical research priorities in lung transplantation

This report summarizes the discussion and recommendations from the June 2017 NHLBI-AATS Workshop on Identifying Collaborative Clinical Research Priorities in Lung Transplantation.

Frailty phenotypes and mortality after lung transplantation: A prospective cohort study

Frailty is associated with increased mortality among lung transplant candidates. We sought to determine the association between frailty, as measured by the Short Physical Performance Battery (SPPB), and mortality after lung transplantation. In a multicenter prospective cohort study of adults who underwent lung transplantation, preoperative frailty was assessed with the SPPB (n = 318) and, in a secondary analysis, the Fried Frailty Phenotype (FFP; n = 299). We tested the association between preoperative frailty and mortality following lung transplantation with propensity score-adjusted Cox models. We calculated postestimation marginalized standardized risks for 1-year mortality by frailty status using multivariate logistic regression. SPPB frailty was associated with an increased risk of both 1- and 4-year mortality (adjusted hazard ratio [aHR]: 7.5; 95% confidence interval [CI]: 1.6-36.0 and aHR 3.8; 95%CI: 1.8-8.0, respectively). Each 1-point worsening in SPPB was associated with a 20% increased risk of death (aHR: 1.20; 95%CI: 1.08-1.33). Frail subjects had an absolute increased risk of death within the first year after transplantation of 12.2% (95%CI: 3.1%-21%). In secondary analyses, FFP frailty was associated with increased risk of death within the first postoperative year (aHR: 3.8; 95%CI: 1.1-13.2) but not over longer follow-up. Preoperative frailty is associated with an increased risk of death after lung transplantation.

Lung Transplantation with Controlled Donation after Circulatory Death Donors

Purpose: Utilization of donation after circulatory death (DCD) donors has the potential to decrease donor shortage in lung transplantation (LTx). This study reviews the long-term outcome of LTx from DCD donors.

Methods: We included all consecutive DCD (Maastricht Category III) and all donations after brain death (DBD) donor lung transplants at our Center performed between January 2012 and February 2017. Data were analyzed comparing the two groups in regard of survival after LTx as primary outcome.

Results: Median withdrawal to cardiac arrest time was 17 min (interquartile range [IQR]: 11.5–20.5). Median cardiac arrest to cold perfusion was 32 min (IQR: 24.5–36.5). Primary graft dysfunction (PGD) grade 3 at T72 occurred in three recipients. Chronic lung allograft dysfunction (CLAD) led to death in two cases. In DCD group, there was no 90-day mortality. In DCD, group 1- and 3-year survival rates were 100% and 80%. In DBD group, 1- and 3-year survival rates were 85% and 69% (p = 0.4).

Conclusions: Our report confirmed the comparable outcome from DCD donors compared with DBD donors. Utility of DCD donors is a safe option to overcome donor shortage.

Avian lungs: A novel scaffold for lung bioengineering

Allogeneic lung transplant is limited both by the shortage of available donor lungs and by the lack of suitable long-term lung assist devices to bridge patients to lung transplantation. Avian lungs have different structure and mechanics resulting in more efficient gas exchange than mammalian lungs. Decellularized avian lungs, recellularized with human lung cells, could therefore provide a powerful novel gas exchange unit for potential use in pulmonary therapeutics. To initially assess this in both small and large avian lung models, chicken (Gallus gallus domesticus) and emu (Dromaius novaehollandiae) lungs were decellularized using modifications of a detergent-based protocol, previously utilized with mammalian lungs. Light and electron microscopy, vascular and airway resistance, quantitation and gel analyses of residual DNA, and immunohistochemical and mass spectrometric analyses of remaining extracellular matrix (ECM) proteins demonstrated maintenance of lung structure, minimal residual DNA, and retention of major ECM proteins in the decellularized scaffolds. Seeding with human bronchial epithelial cells, human pulmonary vascular endothelial cells, human mesenchymal stromal cells, and human lung fibroblasts demonstrated initial cell attachment on decellularized avian lungs and growth over a 7-day period. These initial studies demonstrate that decellularized avian lungs may be a feasible approach for generating functional lung tissue for clinical therapeutics.

Frailty and clinical benefits with lung transplantation

BACKGROUND

The Fried frailty phenotype is associated with morbidity and mortality in lung transplant (LTx) candidates, but its clinical application and association with post-transplant outcomes are not well defined. We assessed 2 alternate frailty indices in LTx candidates and evaluated associations of frailty with early post-transplant outcomes and 1-year mortality.

METHODS

Frailty was prospectively evaluated in 50 LTx candidates using the Fried and 2 alternate phenotypic indices, one using variables readily available to clinicians and one using variables from an existing data set. Agreement between indices and associations with related measures were assessed to establish validity. The data set index was then applied retrospectively to 221 LTx patients. Post-transplant outcomes were compared between frail and non-frail patients using t-tests and multivariable regression analysis.

RESULTS

Frailty prevalence among the 3 indices was 26% to 30%, and the κ agreement was 0.38 to 0.41. All indices had moderate correlations with London Chest Activity of Daily Living (r = 0.48-0.62) and Short-Physical Performance Battery (r = -0.43 to -0.52). In the retrospective cohort, frail LTx candidates had a worse St. George's Respiratory Questionnaire total score (73 ± 12vs 62 ± 12, p < 0.001). Frail candidates had a larger improvement with transplant in the St. George's Respiratory Questionnaire (-52 ± 19vs -43 ± 18, p = 0.002) and 6-minute walk distance (191 ± 119vs 129 ± 94m, p = 0.001). Frailty was not associated with hospital length of stay or 1-year mortality.

CONCLUSIONS

There was good construct validity and acceptable agreement among the frailty indices. Despite significant disability pre-transplant, frail LTx candidates derived significant benefit with transplantation.

Lung xenotransplantation

PURPOSE OF REVIEW

This review describes the most recent progress in xeno lung transplantation (XLTx) to date. It describes the potential mechanisms of early xeno lung graft loss, as well as the latest therapeutic strategies to overcome them.

RECENT FINDINGS

Using ex-vivo perfusion models of porcine lungs with human blood, the use of genetically modified pig lungs along with novel pharmaceutical approaches has recently been studied. Strategies that have demonstrated improved lung survival include the knockout of known xenoantigens (GalTKO and N-glycolylneuraminic acid-KO), genes that regulate complement activation (hCD46 and hCD55), as well as the inflammation/coagulation cascade (human leukocyte antigen-E, human thrombomodulin, human endothelial protein C receptor, hCD47, hCD39, hCD73 and heme oxygenase-1). Furthermore, pharmacologic interventions including the depletion of pulmonary intravascular macrophages or von Willebrand factor, inhibition of thromboxane synthase and blockade of histamine receptors have also demonstrated protective effects on xeno lung grafts. Using in-vivo pig to nonhuman primate lung transplant models, these approaches have been shown to extend pulmonary xenograft survival to 5 days.

SUMMARY

The development of new multitransgenic GalTKO pigs has demonstrated prolongation of porcine xenograft survival; however, advancement in XLTx has remained frustratingly limited. Further intensive and innovative strategies including genetic manipulation of donors, as well as inflammation/coagulation dysregulation, are required to make XLTx a clinical possibility.

Anellovirus loads are associated with outcomes in pediatric lung transplantation

Anelloviruses are DNA viruses ubiquitously present in human blood. Due to their elevated levels in immunosuppressed patients, anellovirus levels have been proposed as a marker of immune status. We hypothesized that low anellovirus levels, reflecting relative immunocompetence, would be associated with adverse outcomes in pediatric lung transplantation. We assayed blood samples from 57 patients in a multicenter study for alpha- and betatorquevirus, two anellovirus genera. The primary short-term outcome of interest was acute rejection, and longer-term outcomes were analyzed individually and as "composite" (death, chronic rejection, or retransplant within 2 years). Patients with low alphatorquevirus levels at 2 weeks post-transplantation were more likely to develop acute rejection within 3 months after transplant (P = .013). Low betatorquevirus levels at 6 weeks and 6 months after transplant were associated with death (P = .047) and the composite outcome (P = .017), respectively. There was an association between low anellovirus levels and adverse outcomes in pediatric lung transplantation. Alphatorquevirus levels were associated with short-term outcomes (ie, acute rejection), while betatorquevirus levels were associated with longer-term outcomes (ie, death, or composite outcome within 2 years). These observations suggest that anelloviruses may serve as useful biomarkers of immune status and predictors of adverse outcomes.

Recent advances in extracorporeal life support as a bridge to lung transplantation

INTRODUCTION

Invasive mechanical respiratory support in candidate bridging to transplant (BTT) has become common practice in recent years. This usually consists of mechanical ventilation, extracorporeal life support (ECLS) or a combination of both techniques. Areas covered: This review covers epidemiology, technical considerations, indications and outcome of ELCS as BTT. Published literature was identified by searching the MEDLINE bibliographic database (1946-present) and appropriate papers were reviewed. In a retrospective analysis of the period 2010-2016 (n = 92 cases of ECLS bridging, 62% ECLS only) at our institution, bridging success was 73%, with 1-year survival among patients surviving to transplant 78%, surpassing our previously published results between 2005-2009 (bridging success 58%, 1-year survival 58%, p = 0.002 and p = 0.02, respectively). Expert commentary: While ECLS success has influenced lung transplant selection criteria, bridging remains technically and ethically challenging. Candidate selection and organ allocation are crucial to achieving acceptable results.

Optimizing the Use of Available Lungs

BACKGROUND

Organ transplantation, the treatment of choice in organ failure, is penalized by the lack of organs. Because the increase in the number of donors is not proportional throughout the different age groups, there is no increase in lung transplantations. The aim of this work was to analyze the use of available lungs and evaluate strategies that may help increase transplantations.

METHODS

We analyzed the activity of lung transplantation in 2015, divided into various allocation programs. We also examined the surplus organs, in particular, their origin, their destination, their offer's outcome, the characteristics of the donor and the proposed organ, and the reasons for rejection.

RESULTS

In 2015, 112 lung transplantations were performed: 66 (68.9%) with regional organs, 46 (41.1%) with extraregional organs; 21 (45.6%) of these were allocated as emergencies/return, and 25 (54.4%) as surplus (19 in the North macroarea, 6 in the South macroarea). The number of surplus lungs was 148: 67 from the North macroarea, 71 from the South macroarea, and 10 from abroad. No organ procured in the North macroarea was transplanted in the South macroarea, whereas 6 lungs coming from the South macroarea were transplanted in the North.

CONCLUSIONS

The acceptance criteria are not the same in different transplant centers and they include not only clinical parameters, but also ischemia time and composition of the waiting list at the time of the offer, quality and accessibility of the intensive care units where the donor is located, and organizational reasons. Offering organs which can not be transplanted within the region to other centers, without clinical foreclosures is a system that increases transplant activities by maximizing the available resources.

Extracorporeal life support as a bridge to lung transplantation-experience of a high-volume transplant center

OBJECTIVES

Extracorporeal life support (ECLS) is increasingly used to bridge deteriorating patients awaiting lung transplantation (LTx), however, few systematic descriptions of this practice exist. We therefore aimed to review our institutional experience over the past 10 years.

METHODS

In this case series, we included all adults who received ECLS with the intent to bridge to LTx. Data were retrieved from patient charts and our institutional ECLS and transplant databases.

RESULTS

Between January 2006 and September 2016, 1111 LTx were performed in our institution. ECLS was used in 71 adults with the intention to bridge to LTx; of these, 11 (16%) were bridged to retransplantation. The median duration of ECLS before LTx was 10 days (range, 0-95). We used a single dual-lumen venous cannula in 23 patients (32%). Nine of 13 patients (69%) with pulmonary hypertension were bridged by central pulmonary artery to left atrium Novalung. Twenty-five patients (35%) were extubated while on ECLS and 26 patients (37%) were mobilized. Sixty-three patients (89%) survived to LTx. Survival by intention to treat was 66% (1 year), 58% (3 years) and 48% (5 years). Survival was significantly shorter in patients undergoing ECLS bridge to retransplantation compared with first LTx (median survival, 15 months (95% CI, 0-31) versus 60 months (95% CI, 37-83); P = .041).

CONCLUSIONS

In our center experience, ECLS bridge to first lung transplant leads to good short-term and long-term outcomes in carefully selected patients. In contrast, our data suggest that ECLS as a bridge to retransplantation should be used with caution.

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.

Racial and ethnic disparities in lung transplant listing and waitlist outcomes

BACKGROUND

The United States lung transplant registry data demonstrate differences in adult waitlist mortality by race/ethnicity. It is unknown whether these differences persist after risk adjustment or occur secondary to disparities in disease severity at the time of listing.

METHODS

Adult lung transplant waitlist candidates between May 4, 2005 and March 5, 2015 were identified and compared by non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic and Asian race/ethnicity. A competing risk proportional hazards model was used to assess the association of race/ethnicity with the unadjusted and adjusted risk of waitlist death or removal for too sick, transplant, or removal for other reason. Disease illness severity at transplant listing was compared by race/ethnicity.

RESULTS

There were 20,684 lung transplant candidates identified (82% NHW, 9% NHB, 6% Hispanic, 2% Asian and 1% other). Non-white candidates had higher unadjusted waitlist mortality, which was fully mitigated by adjusting for other risk factors (NHB: hazard ratio [HR] 1.05, 95% confidence interval [CI] 0.93 to 1.18; Hispanic: HR 1.02, 95% CI 0.99 to 1.18; Asian: HR 0.90, 95% CI 0.70 to 1.16). Adjusted waitlist access to transplant was lower in non-white candidates (NHB: HR 0.88, 95% CI 0.83 to 0.94; Hispanic: HR 0.87, 95% CI 0.81 to 0.94; Asian: HR 0.83, 95% CI 0.73 to 0.96). NHW candidates with obstructive lung disease and pulmonary fibrosis were older with less illness severity at listing than non-white candidates.

CONCLUSIONS

Within the current lung allocation system, there is no difference in risk-adjusted waitlist mortality by race/ethnicity, but non-white waitlist candidates have lower risk-adjusted access to lung transplant. Non-white candidates are generally younger with greater disease-specific illness severity at the time of lung transplant listing.

Mechanical Circulatory Support as a Bridge to Lung Transplantation: A Single Canadian Institution Review

BACKGROUND

Lung transplant (LTx) waitlists continue to grow internationally. Consequently, more patients are progressing to require mechanical circulatory support (MCS) as a bridge to transplantation (BTT). MCS strategies include interventional lung assist (iLA) and venovenous (VV) and venoarterial (VA) extracorporeal membrane oxygenation (ECMO). We review our series of patients bridged with MCS while listed for LTx.

METHODS

All consecutive patients, listed for LTx requiring MCS as a BTT at the University of Alberta from 2004 to 2015, were included. Patient demographics and outcomes were compared for the 3 groups (iLA, VV-ECMO, and VA-ECMO).

RESULTS

Of the 24 patients supported with MCS devices, 17 were successfully transplanted and 7 died waiting. In total, 25% (n = 6) were bridged with VA-ECMO, 54% (n = 13) with VV-ECMO, and 21% (n = 5) with iLA. Overall, 71% of patients were bridged successfully to LTx. The 1-year survival posttransplantation was 88%.

CONCLUSION

We have demonstrated the feasibility of utilizing the MCS modalities of VA-ECMO, VV-ECMO, and most recently iLA, as a BTT. MCS is a viable strategy for BTT, offering improved survival outcomes for decompensating adult patients awaiting LTx, resulting in excellent survival posttransplantation.

In-vitro evaluation of limitations and possibilities for the future use of intracorporeal gas exchangers placed in the upper lobe position

The lack of donor organs has led to the development of alternative "destination therapies", such as a bio-artificial lung (BA) for end-stage lung disease. Ultimately aiming at a fully implantable BA, general capabilities and limitations of different oxygenators were tested based on the model of BA positioning at the right upper lobe. Three different-sized oxygenators (neonatal, paediatric, and adult) were tested in a mock circulation loop regarding oxygenation and decarboxylation capacities for three respiratory pathologies. Blood flows were imitated by a roller pump, and respiration was imitated by a mechanical ventilator with different FiO₂ applications. Pressure drops across the oxygenators and the integrity of the gas-exchange hollow fibers were analyzed. The neonatal oxygenator proved to be insufficient regarding oxygenation and decarboxylation. Despite elevated pCO₂ levels, the paediatric and adult oxygenators delivered comparable sufficient oxygen levels, but sufficient decarboxylation across the oxygenators was ensured only at flow rates of 0.5 L min. Only the adult oxygenator indicated no significant pressure drops. For all tested conditions, gas-exchange hollow fibers remained intact. This is the first study showing the general feasibility of delivering sufficient levels of gas exchange to an intracorporeal BA via patient's breathing, without damaging gas-exchange hollow fiber membranes.

Outcomes after lung transplantation

With more than 50,000 procedures having been performed worldwide, lung transplantation (LT) has become the standard of care for patients with end-stage chronic respiratory failure. LT leads to dramatic improvements in both pulmonary function and health related quality of life. Survival after LTs has steadily improved, but still lags far behind that observed after other solid organ transplantations, as evidenced by a median survival rate that currently stands at 5.8 years. Because of these disappointing results, the ability of LT to expand survival has been questioned. However, the most recent studies, based on sophisticated statistical modeling suggest that LT confers a survival benefit to the vast majority of lung transplant recipients. Chronic lung allograft dysfunction (CLAD) that develops in about 50% of recipients 5 years after LT is a major impediment to lung transplant survival. A better understanding of the mechanisms underlying CLAD could allow for better post-transplant survival.

Improved metabolism and redox state with a novel preservation solution: implications for donor lungs after cardiac death (DCD)

Lungs donated after cardiac death (DCD) are an underutilized resource for a dwindling donor lung transplant pool. Our study investigates the potential of a novel preservation solution, Somah, to better preserve statically stored DCD lungs, for an extended time period, when compared to low-potassium dextran solution (LPD). We hypothesize that Somah is a metabolically superior organ preservation solution for hypothermic statically stored porcine DCD lungs, possibly improving lung transplant outcomes. Porcine DCD lungs (n = 3 per group) were flushed with and submerged in cold preservation solution. The lungs were stored up to 12 h, and samples were taken from lung tissue and the preservation medium throughout. Metabolomic and redox potential were analyzed using high performance liquid chromatography, mass spectrometry, and RedoxSYS®, comparing substrate and pathway utilization in both preservation solutions. Glutathione reduction was seen in Somah but not in LPD during preservation. Carnitine, carnosine, and n-acetylcarnosine levels were elevated in the Somah medium compared with LPD throughout. Biopsies of Somah exposed lungs demonstrated similar trends after 2 h, up to 12 h. Adenosine gradually decreased in Somah medium over 12 h, but not in LPD. An inversely proportional increase in inosine was found in Somah. Higher oxidative stress levels were measured in LPD. Our study suggests suboptimal metabolic preservation in lungs stored in LPD. LPD had poor antioxidant potential, cytoprotection, and an insufficient redox potential. These findings may have immediate clinical implications for human organs; however, further investigation is needed to evaluate DCD lung preservation in Somah as a viable option for transplant.

Thoracic muscle cross-sectional area is associated with hospital length of stay post lung transplantation: a retrospective cohort study

Low muscle mass is common in lung transplant (LTx) candidates; however, the clinical implications have not been well described. The study aims were to compare skeletal muscle mass in LTx candidates with controls using thoracic muscle cross-sectional area (CSA) from computed tomography and assess the association with pre- and post-transplant clinical outcomes. This was a retrospective, single-center cohort study of 527 LTx candidates [median age: 55 IQR (42-62) years; 54% male]. Thoracic muscle CSA was compared to an age- and sex-matched control group. Associations between muscle CSA and pre-transplant six-minute walk distance (6MWD), health-related quality of life (HRQL), delisting/mortality, and post-transplant hospital outcomes and one-year mortality were evaluated using multivariable regression analysis. Muscle CSA for LTx candidates was about 10% lower than controls (n = 38). Muscle CSA was associated with pre-transplant 6MWD, but not HRQL, delisting or pre- or post-transplant mortality. Muscle CSA (per 10 cm² difference) was associated with shorter hospital stay [0.7 median days 95% CI (0.2-1.3)], independent of 6MWD. In conclusion, thoracic muscle CSA is a simple, readily available estimate of skeletal muscle mass predictive of hospital length of stay, but further study is needed to evaluate the relative contribution of muscle mass versus functional deficits in LTx candidates.

Pattern and Predictors of Hospital Readmission During the First Year After Lung Transplantation

Hospital readmission after lung transplantation negatively affects quality of life and resource utilization. A secondary analysis of data collected prospectively was conducted to identify the pattern of (incidence, count, cumulative duration), reasons for and predictors of readmission for 201 lung transplant recipients (LTRs) assessed at 2, 6, and 12 mo after discharge. The majority of LTRs (83.6%) were readmitted, and 64.2% had multiple readmissions. The median cumulative readmission duration was 19 days. The main reasons for readmission were other than infection or rejection (55.5%), infection only (25.4%), rejection only (9.9%), and infection and rejection (0.7%). LTRs who required reintubation (odds ratio [OR] 1.92; p = 0.008) or were discharged to care facilities (OR 2.78; p = 0.008) were at higher risk for readmission, with a 95.7% cumulative incidence of readmission at 12 mo. Thirty-day readmission (40.8%) was not significantly predicted by baseline characteristics. Predictors of higher readmission count were lower capacity to engage in self-care (incidence rate ratio [IRR] 0.99; p = 0.03) and discharge to care facilities (IRR 1.45; p = 0.01). Predictors of longer cumulative readmission duration were older age (arithmetic mean ratio [AMR] 1.02; p = 0.009), return to the intensive care unit (AMR 2.00; p = 0.01) and lower capacity to engage in self-care (AMR 0.99; p = 0.03). Identifying LTRs at risk may assist in optimizing predischarge care, discharge planning and long-term follow-up.

Lung regeneration: steps toward clinical implementation and use

PURPOSE OF REVIEW

Whole lung tissue engineering is a relatively new area of investigation. In a short time, however, the field has advanced quickly beyond proof of concept studies in rodents and now stands on the cusp of wide-spread scale up to large animal studies. Therefore, this technology is ever closer to being directly clinically relevant.

RECENT FINDINGS

The main themes in the literature include refinement of the fundamental components of whole lung engineering and increasing effort to direct induced pluripotent stem cells and lung progenitor cells toward use in lung regeneration. There is also increasing need for and emphasis on functional evaluation in the lab and in vivo, and the use of all of these tools to construct and evaluate forthcoming clinically scaled engineered lung.

SUMMARY

Ultimately, the goal of the research described herein is to create a useful clinical product. In the intermediate time, however, the tools described here may be employed to advance our knowledge of lung biology and the organ-specific regenerative capacity of lung stem and progenitor cells.

Improving Organ Utilization to Help Overcome the Tragedies of the Opioid Epidemic

Death rates from drug overdoses have nearly doubled since 2003, with over 47 000 deaths in 2014. This is largely attributable to the opioid epidemic. If the unfortunate deaths of otherwise healthy people have yielded an increase in organ donors, then this might serve as perhaps the only comforting factor among this tragic and unnecessary loss of life. In this viewpoint, we present data from the Organ Procurement and Transplantation Network (OPTN) that show how the greatest relative increases in the mechanism of death among deceased donors from 2003 to 2014 were drug overdoses. Unfortunately, despite the absolute increase in the number of donors who died from a drug overdose, the mean organ yield was significantly lower than in other categories, in part due to concerns about disease transmission. In this paper, we present data on the changes in donation from donors with a drug overdose as a result of the opioid epidemic and discuss the need to educate transplant candidates and their physicians about the low risk of disease transmission compared to the greater risk of dying on a transplant waitlist.

Single Versus Double Lung Retransplantation Does Not Affect Survival Based on Previous Transplant Type

BACKGROUND

Survival following retransplantation with a single lung is worse than after double lung transplant. We sought to characterize survival of patients who underwent lung retransplantation based on the type of their initial transplant, single or double.

METHODS

The United Network for Organ Sharing database was queried for adult patients who underwent lung retransplantation from 2005 onward. Patients were excluded if they underwent more than one retransplantation. The patient population was divided into 4 groups based on first followed by second transplant type, respectively: single then single, double then single, double then double, and single then double. Descriptive analysis and Kaplan-Meier survival analysis were performed. A p value less than 0.05 was considered significant.

RESULTS

A total of 410 patients underwent retransplantation in the study time period. Overall mean survival for all patients who underwent retransplantation was 1,213 days. Kaplan-Meier survival analysis demonstrated no difference in graft survival between the 4 study groups (p = 0.146).

CONCLUSIONS

There was no significant difference in graft survival between recipients of retransplant with single or double lungs when stratified by previous transplant type. These results suggest that when retransplantation is performed, single lung retransplantation should be considered, regardless of previous transplant type, in an effort to maximize organ resources.

Development of a biomimetic microfluidic oxygen transfer device

Blood oxygenators provide crucial life support for patients suffering from respiratory failure, but their use is severely limited by the complex nature of the blood circuit and by complications including bleeding and clotting. We have fabricated and tested a multilayer microfluidic blood oxygenation prototype designed to have a lower blood prime volume and improved blood circulation relative to current hollow fiber cartridge oxygenators. Here we address processes for scaling the device toward clinically relevant oxygen transfer rates while maintaining a low prime volume of blood in the device, which is required for clinical applications in cardiopulmonary support and ultimately for chronic use. Approaches for scaling the device toward clinically relevant gas transfer rates, both by expanding the active surface area of the network of blood microchannels in a planar layer and by increasing the number of microfluidic layers stacked together in a three-dimensional device are addressed. In addition to reducing prime volume and enhancing gas transfer efficiency, the geometric properties of the microchannel networks are designed to increase device safety by providing a biomimetic and physiologically realistic flow path for the blood. Safety and hemocompatibility are also influenced by blood-surface interactions within the device. In order to further enhance device safety and hemocompatibility, we have demonstrated successful coating of the blood flow pathways with human endothelial cells, in order to confer the ability of the endothelium to inhibit coagulation and thrombus formation. Blood testing results provide confirmation of fibrin clot formation in non-endothelialized devices, while negligible clot formation was documented in cell-coated devices. Gas transfer testing demonstrates that the endothelial lining does not reduce the transfer efficiency relative to acellular devices. This process of scaling the microfluidic architecture and utilizing autologous cells to line the channels and mitigate coagulation represents a promising avenue for therapy for patients suffering from a range of acute and chronic lung diseases.

The Impact of Alemtuzumab and Basiliximab Induction on Patient Survival and Time to Bronchiolitis Obliterans Syndrome in Double Lung Transplantation Recipients

We examined the effect of alemtuzumab and basiliximab induction therapy on patient survival and freedom from bronchiolitis obliterans syndrome (BOS) in double lung transplantation. The United Network for Organ Sharing database was reviewed for adult double lung transplant recipients from 2006 to 2013. The primary outcome was risk-adjusted all-cause mortality. Secondary outcomes included time to BOS. There were 6117 patients were identified, of whom 738 received alemtuzumab, 2804 received basiliximab, and 2575 received no induction. Alemtuzumab recipients had higher lung allocation scores compared with basiliximab and no-induction recipients (41.4 versus 37.9 versus 40.7, p < 0.001) and were more likely to require mechanical ventilation before to transplantation (21.7% versus 6.5% versus 6.2%, p < 0.001). Median survival was longer for alemtuzumab and basiliximab recipients compared with patients who received no induction (2321 versus 2352 versus 1967 days, p = 0.001). Alemtuzumab (hazard ratio 0.80, 95% confidence interval 0.67-0.95, p = 0.009) and basiliximab induction (0.88, 0.80-0.98, p = 0.015) were independently associated with survival on multivariate analysis. At 5 years, alemtuzumab recipients had a lower incidence of BOS (22.7% versus 55.4 versus 55.9%), and its use was independently associated with lower risk of developing BOS on multivariate analysis. While both induction therapies were associated with improved survival, patients who received alemtuzumab had greater median freedom from BOS.