OPTN/SRTR 2013 Annual Data Report: lung

The Organ Transplant Imperative

More than 120,000 US patients were listed for solid organ transplants in 2016. Although data are scarce, we suspect that many of these patients will die while awaiting transplant and without engaging in goals-of-care discussions with their physicians. The challenges of addressing goals of care in patients with malignancy, end-stage renal disease, and heart failure have been studied. However, there is sparse literature on addressing goals of care throughout the dynamic process of transplant assessment and listing. We propose the concept of an organ transplant imperative, which is the perceived obligation by patients and health care providers to proceed with organ transplant and to avoid advance care planning and triggered goals-of-care discussions, even in situations in which patients' clinical trajectories have worsened, resulting in poor quality of life and low likelihood of meaningful survival. We situate this concept within the paradigms of clinical inertia and the treatment and technological imperatives. We illustrate this concept by describing a patient with end-stage liver disease (ESLD) who was hoping for a liver transplant, who was caught between the conflicting perspectives of specialist and primary care physicians, and who died of complications of ESLD without experiencing the benefits of advance care planning. Greater awareness of the transplant imperative should generate a shared understanding among specialists, generalists, and patients and will provide opportunities for more formalized involvement of palliative medicine experts in the care of transplant patients.

Cytokine filtration modulates pulmonary metabolism and edema formation during ex vivo lung perfusion

BACKGROUND

Ex vivo lung perfusion (EVLP) has improved the process of donor lung management. Cytokine accumulation during EVLP has been shown to correlate with worse outcome after lung transplantation. Our objective in this study was to test the safety and efficacy of cytokine filtration during EVLP in a large animal model.

METHODS

Pig donor lungs were preserved for 24 hours at 4°C, followed by 12 hours of EVLP, according to the Toronto protocol. The perfusate was continuously run through an absorbent device (CytoSorb) via a veno-venous shunt from the reservoir in the filter group. EVLP was performed according to the standard protocol in the control group (n = 5 each). EVLP physiology, lung X-ray, perfusate biochemistry, inflammatory response and microscopic injury were assessed.

RESULTS

Cytokine filtration significantly improved airway pressure and dynamic compliance during the 12-hour perfusion period. Lung X-rays acquired at the end of perfusion showed increased consolidation in the control group. Electrolyte imbalance, determined by increased hydrogen, potassium and calcium ion concentrations in the perfusate, was markedly worsened in the control group. Glucose consumption and lactate production were markedly reduced, along with the lactate/pyruvate ratio in the filter group. Cytokine expression profile, tissue myeloperoxidase activity and microscopic lung injury were significantly reduced in the filter group.

CONCLUSIONS

Continuous perfusate filtration through sorbent beads is effective and safe during prolonged EVLP. Cytokine removal decreased the development of pulmonary edema and electrolyte imbalance through the suppression of anaerobic glycolysis and neutrophil activation in this setting. Further studies are needed to test the beneficial effect of cytokine filtration on post-transplant lung function.

Hospital cost and length of stay in idiopathic pulmonary fibrosis

OBJECTIVE

To provide a detailed picture of the economic impact of hospitalization in idiopathic pulmonary fibrosis (IPF) and to identify factors associated with cost and length of stay (LOS).

METHODS

In this retrospective cross-sectional study using the Nationwide Inpatient Sample (NIS), this study included hospitalizations for IPF (ICD-9-CM 516.3) with a principal diagnosis of respiratory disease (ICD-9-CM 460-519) from 2009-2011; lung transplant admissions were excluded. Total inpatient cost, LOS, in-hospital death, and discharge disposition were reported. Linear regression models were used to determine variables predictive of LOS and cost.

RESULTS

From 2009-2011, 22,350 non-transplant IPF patients with a principal diagnosis of respiratory disease were admitted: mean (±SE) age was 70.0 (0.32), and 49.1% were female. While in hospital, 11.4% of patients received mechanical ventilation and 8.9% received non-invasive ventilation. Mean (±SE) LOS was 7.4 (0.15) days overall (p < .001). The mean (±SD) admission cost was $16,042 (±631). Of hospitalized patients, 14.1% died, 20.6% transferred facilities, and 46.4% were routinely discharged. The adjusted LOS (95% CI) for patients with and without mechanical ventilation was 16.1 days (15-17.5) vs. 6.3 (6-6.5); adjusted costs were $48,772 (43,979-53,565) vs. $11,861 (11,292-12,431).

LIMITATIONS

The positive predictive value of the algorithm used to identify IPF is not optimal. The NIS database does not follow patients longitudinally, and claims after admission are not available. Claims do not indicate whether listed diagnoses were present on admission or developed during hospitalization. The exclusion of transplant-related expenditures lead to under-estimation of cost.

CONCLUSION

Using a nationally-representative database, we found IPF respiratory-related hospitalizations represent a significant economic burden with ∼7,000 non-transplant IPF admissions per year, at a mean cost of $16,000 per admission. Mechanical ventilation is associated with statistically significant increases in LOS and cost. Therapeutic advances that reduce rates and costs of IPF hospitalizations are needed.

Lungs donated after circulatory death and prolonged warm ischemia are transplanted successfully after enhanced ex vivo lung perfusion using adenosine A2B receptor antagonism

OBJECTIVE

The current supply of acceptable donor lungs is not sufficient for the number of patients awaiting transplantation. We hypothesized that ex vivo lung perfusion (EVLP) with targeted drug therapy would allow successful rehabilitation and transplantation of donation after circulatory death lungs exposed to 2 hours of warm ischemia.

METHODS

Donor porcine lungs were procured after 2 hours of warm ischemia postcardiac arrest and subjected to 4 hours of cold preservation or EVLP. ATL802, an adenosine A_2B receptor antagonist, was administered to select groups. Four groups (n = 4/group) were randomized: cold preservation (Cold), cold preservation with ATL802 during reperfusion (Cold + ATL802), EVLP (EVLP), and EVLP with ATL802 during ex vivo perfusion (EVLP + ATL802). Lungs subsequently were transplanted, reperfused, and assessed by measuring dynamic lung compliance and oxygenation capacity.

RESULTS

EVLP + ATL802 significantly improved dynamic lung compliance compared with EVLP (25.0 ± 1.8 vs 17.0 ± 2.4 mL/cmH₂O, P = .04), and compared with cold preservation (Cold: 12.2 ± 1.3, P = .004; Cold + ATL802: 10.6 ± 2.0 mL/cmH₂O, P = .002). Oxygenation capacity was highest in EVLP (440.4 ± 37.0 vs Cold: 174.0 ± 61.3 mm Hg, P = .037). No differences in oxygenation or pulmonary edema were observed between EVLP and EVLP + ATL802. A significant decrease in interleukin-12 expression in tissue and bronchoalveolar lavage was identified between groups EVLP and EVLP + ATL802, along with less neutrophil infiltration.

CONCLUSIONS

Severely injured donation after circulatory death lungs subjected to 2 hours of warm ischemia are transplanted successfully after enhanced EVLP with targeted drug therapy. Increased use of lungs after uncontrolled donor cardiac death and prolonged warm ischemia may be possible and may improve transplant wait list times and mortality.

Successful Lung Transplantation From Hepatitis C Positive Donor to Seronegative Recipient

Lung transplantation using RNA+ hepatitis C (HCV+) donors to seronegative recipients is not currently performed due to the very high risk of transmission. Previous reports have shown poor survival when this practice was applied. The emergence of new direct-acting antiviral drugs (DAA) suggests a high chance of sustained virologic response in immunocompetent patients. We report here successful transplantation of lungs from HCV+ donor to HCV- recipient. The recipient was an HCV- patient with chronic lung allograft dysfunction. Viral transmission occurred early posttransplant but excellent clinical outcomes were observed including elimination of HCV after 12 weeks of treatment using DAAs.

Incidence, Predictors, and Outcomes of Early Atrial Arrhythmias After Lung Transplant: A Systematic Review and Meta-Analysis

OBJECTIVES

This study sought to determine the incidence, predictors, and prognostic implications of early post-lung transplant atrial arrhythmias (AAs).

BACKGROUND

Although frequently encountered, the prognostic implications of early AAs after lung transplant remain uncertain.

METHODS

A systematic review of MEDLINE and the Cochrane Library was conducted for all studies that reported early post-lung transplant AAs. Random-effects DerSimonian-Laird risk ratios (RRs) were calculated for categorical variables and standardized mean difference (SMD) for continuous variables.

RESULTS

A total of 12 studies with 3,203 patients (mean age 57 ± 3 years; 52% males) were included. The incidence of early post-lung transplant AAs during hospitalization was 26.6% at mean follow-up duration of 6.7 days. Predictors of post-lung transplant AAs included advanced age (SMD: 0.50; 95% confidence interval [CI]: 0.35 to 0.64), male gender (RR: 1.37; 95% CI: 1.28 to 1.47), history of smoking (RR: 1.23; 95% CI: 1.05 to 1.46), hypertension (RR: 1.35; 95% CI: 1.13 to 1.59), hyperlipidemia (RR: 1.39; 95% CI: 1.18 to 1.63), coronary artery disease (RR: 1.40; 95% CI: 1.12 to 1.7), left atrial diameter (SMD: 0.25; 95% CI: 0.07 to 0.44), and restrictive lung disease (RR: 1.34; 95% CI: 1.13 to 1.59). Post-lung transplant AAs were associated with increased all-cause mortality (adjusted RR: 1.63; 95% CI: 1.22 to 2.19) at mean follow-up of 27.8 months and length of hospital stay (36.5 ± 16.5 days vs. 26.1 ± 14.3 days; p < 0.001).

CONCLUSIONS

Early AAs post-lung transplant are associated with increased mortality and length of hospital stay. Advanced age, male sex, smoking, hypertension, hyperlipidemia, coronary artery disease, increased left atrial diameter, and restrictive lung disease are independent predictors of early AAs in post-lung transplant patients.

Lung Transplant Mortality Is Improving in Recipients With a Lung Allocation Score in the Upper Quartile

BACKGROUND

Since the introduction of the Lung Allocation Score (LAS), the mean LAS has risen. Still, it remains uncertain whether mortality has improved in the most severely ill lung transplant recipients over this time period.

METHODS

Using the United Network for Organ Sharing database, we identified 3,548 adult lung transplant recipients from May 4, 2005, to March 31, 2014, with a match-time LAS in the upper quartile (>75th%ile). We divided this population across three eras: 1 = May 4, 2005, to December 31, 2008 (n = 1,280); 2 = January 1, 2009, to December 31, 2011 (n = 1,266); and 3 = January 1, 2012, to March 31, 2014 (n = 1,002). Cox proportional hazards models were constructed for the primary outcomes of 30-day and 1-year mortality to assess the independent impact of the era of transplantation.

RESULTS

The mean LAS at time of transplant for patients in the upper quartile in eras 1, 2, and 3 was 63, 73, and 79, respectively (p < 0.001). Later eras of transplantation benefited from a significant improvement in survival at 1 year (log-rank p = 0.001) but not at 30 days (log-rank p = 0.152). After risk adjustment, lung transplantation in more recent eras was associated with improved mortality at both 30 days (era 3 hazard ratio [HR] = 0.50, 95% confidence interval [CI] 0.32% to 0.78%, p = 0.002) and 1 year (era 2 HR = 0.77, 95% CI 0.64% to 0.94%, p = 0.008; era 3 HR = 0.54, 95% CI 0.43% to 0.68%, p < 0.001).

CONCLUSIONS

Despite a progressively rising LAS, survival is improving among recipients with the highest LAS at the time of lung transplantation. This calls into question the notion of a maximum LAS beyond which lung transplantation becomes futile, a so-called LAS ceiling.

Gender differences in long-term survival post-transplant: A single-institution analysis in the lung allocation score era

The purpose of this study was to clarify the significance of recipient gender status on lung transplant outcomes in a large single-institution experience spanning three decades, we analyzed data from all lung transplants performed in our institution since 1986. Kaplan-Meier curves and Cox proportional hazard models were used to evaluate the effect of recipient characteristics on survival and BOS score ≥1-free survival. Logistic regression analysis was used to explore the association of gender with short-term graft function. About 876 lung transplants were performed between 1986 and 2016. Kaplan-Meier survival estimates at 5 years post-transplant for females vs males in the LAS era were 71% vs 58%. In the LAS era, females showed greater unadjusted BOS≥1-free survival than males (35% vs 25%, P=.02) over 5 years. Female gender was the only factor in the LAS era significantly associated with improved adjusted 5-year survival [HR 0.56 (95% CI 0.33, 0.95) P=.03]. Conversely, in the pre-LAS era female gender was not associated with improved survival. Female recipients showed significantly improved survival over 5 years compared to males in the LAS era. A prospective analysis of biologic and immunologic differences is warranted.

Telomere length in patients with pulmonary fibrosis associated with chronic lung allograft dysfunction and post-lung transplantation survival

BACKGROUND

Prior studies have shown that patients with pulmonary fibrosis with mutations in the telomerase genes have a high rate of certain complications after lung transplantation. However, few studies have investigated clinical outcomes based on leukocyte telomere length.

METHODS

We conducted an observational cohort study of all patients with pulmonary fibrosis who underwent lung transplantation at a single center between January 1, 2007, and December 31, 2014. Leukocyte telomere length was measured from a blood sample collected before lung transplantation, and subjects were stratified into 2 groups (telomere length <10th percentile vs ≥10th percentile). Primary outcome was post-lung transplant survival. Secondary outcomes included incidence of allograft dysfunction, non-pulmonary organ dysfunction, and infection.

RESULTS

Approximately 32% of subjects had a telomere length <10th percentile. Telomere length <10th percentile was independently associated with worse survival (hazard ratio 10.9, 95% confidence interval 2.7-44.8, p = 0.001). Telomere length <10th percentile was also independently associated with a shorter time to onset of chronic lung allograft dysfunction (hazard ratio 6.3, 95% confidence interval 2.0-20.0, p = 0.002). Grade 3 primary graft dysfunction occurred more frequently in the <10th percentile group compared with the ≥10th percentile group (28% vs 7%; p = 0.034). There was no difference between the 2 groups in incidence of acute cellular rejection, cytopenias, infection, or renal dysfunction.

CONCLUSIONS

Telomere length <10th percentile was associated with worse survival and shorter time to onset of chronic lung allograft dysfunction and thus represents a biomarker that may aid in risk stratification of patients with pulmonary fibrosis before lung transplantation.

Determinants of pre-transplantation pectoralis muscle area (PMA) and post-transplantation change in PMA in lung transplant recipients

BACKGROUND

This study aimed to determine predictors of pectoralis muscle area (PMA) and assess change in PMA following lung transplantation and its relationship to outcomes.

METHODS

A retrospective review of 88 lung transplant recipients at a single center was performed. PMA was determined on a single axial slice from chest computerized tomography. Pectoralis muscle index (PMI) was calculated from the PMA divided by the height squared.

RESULTS

PMI decreased post-transplantation (8.1±2.8 cm² /m² pre-transplantation, 7.5±2.9 cm² /m² at 6 months, and 7.6±2.7 cm² /m² at 12 months, P<.05). Chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) were predictors of pre-transplant PMI (β=-2.3, P=.001 for COPD; β=2.1, P<.001 for ILD) and percent change in PMI at 12 months post-transplantation relative to baseline (β=19.2, P=.04 for COPD; β=-20.1, P=.01 for ILD). Patients in the highest quartile for PMI change at 12 months had fewer ventilator days compared with patients in the other quartiles (P=.03).

CONCLUSIONS

Underlying diagnosis was a significant predictor of both pre-transplantation PMI and change in PMI post-transplantation. Further studies of PMI are needed to determine its clinical utility in predicting outcomes following lung transplantation.

Lung Transplant Center Volume Ameliorates Adverse Influence of Prolonged Ischemic Time on Mortality

The influence of prolonged ischemic time on outcomes after lung transplant is controversial, but no research has investigated ischemic time in the context of center volume. We used data from the United Network for Organ Sharing to estimate the influence of ischemic time on patient survival conditional on center volume in the post-lung allocation score era (2005-2015). The analytic sample included 14 877 adult lung transplant recipients, of whom 12 447 were included in multivariable survival analysis. Patient survival was improved in high-volume centers compared with low-volume centers (log-rank test p = 0.001), although mean ischemic times were longer at high-volume centers (5.16 ± 1.70 h vs. 4.83 ± 1.63 h, p < 0.001). Multivariable Cox proportional hazards regression stratified by transplant center found an adverse influence of longer ischemic time at low-volume centers but not at high-volume centers. At centers performing 50 transplants in the period 2005-2015, for example, 8 versus 6 h of ischemia were associated with an 18.9% (95% confidence interval 6.5-32.7%; p < 0.001) greater mortality hazard, whereas at centers performing 350 transplants in this period, no differences in survival by ischemic time were predicted. Despite longer mean ischemic time at high-volume transplant centers, these centers had favorable patient outcomes and no adverse survival implications of prolonged ischemia.

Missing Domains of Lung Transplant Patient Selection

The goal of consistent, predictable, and improved outcomes has continued to elude the scientific community in the 30 years since lung transplantation became the procedure of choice for patients with terminal, nonmalignant lung disease.

Background:

Although there is consensus regarding disease-specific indications for lung transplant, ambiguity remains regarding how patient-specific attributes should influence lung transplant candidacy. This study had 3 aims (1) to establish the missing domains of the interdisciplinary assessment of the lung transplant candidate, (2) to have these domains validated by an international panel of lung transplant experts, and (3) to recommend the next step for inclusion of these domains into the lung transplant candidate selection process.

Methods:

Three levels of evidence were reviewed. A search for standards and guidelines, a comprehensive literature review, and a validation of domains by experts were conducted.

Results:

Seven domains of patient attributes were identified as relevant to lung transplant patient selection: cognitive performance, frailty, psychological factors, self-efficacy, social support, quality of life, and sociodemographic factors. Within each domain, several elements were identified to be incorporated in the process of patient assessment.

Conclusion:

Assessment of the missing domains and elements should be incorporated into the interdisciplinary lung transplant evaluation process. Standardized recognition and reporting of the patient-specific attributes will inform the work of individual transplant programs and the international transplant community. Further study is needed to associate these patient attributes with transplant outcomes. Improved understanding is needed regarding how nurses assess lung transplant candidates and how they communicate their findings within interdisciplinary settings.

Intrapulmonary Percussive Ventilation as a Lung Recruitment Strategy in Brain-Dead Organ Donors

OBJECTIVE

To determine the strength of the evidence evaluating the effectiveness of intrapulmonary percussive ventilation (IPV) as a safe alternative or adjunctive therapy to traditional chest physiotherapy (CPT) among potential organ donors.

DATA SOURCES

Literature search conducted from February 2015 to November 2015 using PubMed, Cumulative Index of Nursing and Allied Health Literature, Scopus, and bibliographies of pertinent articles. Search Terms: Intrapulmonary percussive ventilation, chest physiotherapy, chest wall oscillation, organ donors, and ventilation.

STUDY SELECTION

Articles in English from 1994 to present directly compared IPV to CPT or conventional (no) therapy.

DATA EXTRACTION

Association of Critical-Care Nurses Levels of Evidence was used to determine the strength of evidence. Level B and level C articles were reviewed.

DATA SYNTHESIS

No studies were found using IPV in the donor population. Results from studies using IPV in other populations indicated IPV had no adverse effects, improved sputum clearance and oxygenation, and reduced atelectasis and pneumonia in patients with artificial airways.

CONCLUSION

Intrapulmonary percussive ventilation may be a safe and effective alternative or adjunctive to CPT therapy and improve the number of lungs available for transplantation. Clinical research is essential to determine the effectiveness of this therapy for lung recruitment in the donor population.

Influence of specific thoracic donor therapy on kidney donation and long-term kidney graft survival

OBJECTIVE

To analyze the impact of a specific thoracic donor-treatment protocol (including restrictive fluid balance) on kidney donation and on kidney graft survival.

METHODS

A cohort study. Lung Donors and kidney recipients from 2003 to 2008 were the pre-protocol cohort, and those from 2009 to 2013 were the protocol cohort. The main outcome variables were graft survival and rate of kidney donation.

RESULTS

Kidney donation rates were similar in both periods (86.2 vs. 86.2 %; p > 0.05). Both donors and kidney recipients were older and with more comorbidities in the protocol group and this is the reason there were more cases of delayed graft function (differences not statistically significant) and with higher sequential creatinine levels of kidney recipients during the protocol period. However, graft survival was similar in both groups. The probability of graft survival 5 years after transplantation was 0.75 (95 % confidence interval 0.65-0.85) in the pre-protocol cohort and 0.81 (0.70-0.92) in the protocol cohort.

CONCLUSIONS

Specific treatment for multi-organ donors including restrictive fluid balance does not affect kidney donation or kidney graft loss, and has no impact on long-term viability. Hemodynamics must be closely monitored by medical personnel with specific training.

Interferon Gamma and Contact-dependent Cytotoxicity Are Each Rate Limiting for Natural Killer Cell-Mediated Antibody-dependent Chronic Rejection

Natural killer (NK) cells are key components of the innate immune system. In murine cardiac transplant models, donor-specific antibodies (DSA), in concert with NK cells, are sufficient to inflict chronic allograft vasculopathy independently of T and B cells. In this study, we aimed to determine the effector mechanism(s) required by NK cells to trigger chronic allograft vasculopathy during antibody-mediated rejection. Specifically, we tested the relative contribution of the proinflammatory cytokine interferon gamma (IFN-γ) versus the contact-dependent cytotoxic mediators of perforin and the CD95/CD95L (Fas/Fas ligand [FasL]) pathway for triggering these lesions. C3H/HeJ cardiac allografts were transplanted into immune-deficient C57BL/6 rag-/- γc-/- recipients, who also received monoclonal anti-major histocompatibility complex (MHC) class I DSA. The combination of DSA and wild-type NK cell transfer triggered aggressive chronic allograft vasculopathy. However, transfer of IFN-γ-deficient NK cells or host IFN-γ neutralization led to amelioration of these lesions. Use of either perforin-deficient NK cells or CD95 (Fas)-deficient donors alone did not alter development of vasculopathy, but simultaneous disruption of NK cell-derived perforin and allograft Fas expression resulted in prevention of these abnormalities. Therefore, both NK cell IFN-γ production and contact-dependent cytotoxic activity are rate-limiting effector pathways that contribute to this form of antibody-induced chronic allograft vasculopathy.

Improved waitlist and transplant outcomes for pediatric lung transplantation after implementation of the lung allocation score

BACKGROUND

Although the lung allocation score (LAS) has not been considered valid for lung allocation to children, several additional policy changes for pediatric lung allocation have been adopted since its implementation. We compared changes in waitlist and transplant outcomes for pediatric and adult lung transplant candidates since LAS implementation.

METHODS

The United Network for Organ Sharing database was reviewed for all lung transplant listings during the period 1995 to June 2014. Outcomes were analyzed based on date of listing (pre-LAS vs post-LAS) and candidate age at listing (adults >18 years, adolescents 12 to 17 years, children 0 to 11 years).

RESULTS

Of the 39,962 total listings, 2,096 (5%) were for pediatric candidates. Median waiting time decreased after LAS implementation for all age groups (adults: 379 vs 83 days; adolescents: 414 vs 104 days; children: 211 vs 109 days; p < 0.001). The proportion of candidates reaching transplant increased after LAS (adults: 52.6% vs 71.6%, p < 0.001; adolescents: 40.3% vs 61.6%, p < 0.001; children: 42.4% vs 50.9%, p = 0.014), whereas deaths on the waitlist decreased (adults: 28.0% vs 14.4%, p < 0.001; adolescents: 33.1% vs 20.9%, p < 0.001; children: 32.2% vs 25.0%; p = 0.025), despite more critically ill candidates in all groups. Median recipient survival increased after LAS for adults and children (adults: 5.1 vs 5.5 years, p < 0.001; children: 6.5 vs 7.6 years, p = 0.047), but not for adolescents (3.6 vs 4.3 years, p = 0.295).

CONCLUSIONS

Improvements in waiting time, mortality and post-transplant survival have occurred in children after LAS implementation. Continued refinement of urgency-based allocation to children and broader sharing of pediatric donor lungs may help to maximize these benefits.

Comprehensive Care of the Lung Transplant Patient

Lung transplantation has evolved into a life-saving treatment with improved quality of life for patients with end-stage respiratory failure unresponsive to other medical or surgical interventions. With improving survival rates, the number of lung transplant recipients with preexisting and posttransplant comorbidities that require attention continues to increase. A partnership between transplant and nontransplant care providers is necessary to deliver comprehensive and optimal care for transplant candidates and recipients. The goals of this partnership include timely referral and assistance with transplant evaluation, optimization of comorbidities and preparation for transplantation, management of common posttransplant medical comorbidities, immunization, screening for malignancy, and counseling for a healthy lifestyle to maximize the likelihood of a good outcome. We aim to provide an outline of the main aspects of the care of candidates for and recipients of lung transplants for nontransplant physicians and other care providers.

How can we improve the quality of transplantable lungs?

INTRODUCTION

Optimization of lungs for organ donation is becoming increasingly important as donation rates stagnate despite growing waiting lists. Improving procurement and utilization of donated lungs has the ability to reduce mortality and time on the lung transplantation (LTx) waiting list. Additionally, assessment and optimization of donor lungs can reduce both early and late post-LTx morbidity and mortality, as well as reduce overall costs and resource utility. Areas covered: Strategies that we will discuss in detail include intensive care management practices, such as targeted ventilation protocols and therapeutic bronchoscopy, as well as the ever expanding possibilities within the arena of ex vivo lung perfusion (EVLP). Expert commentary: Donor lung quality is currently optimized both in vivo prior to organ procurement, and also via EVLP circuits. Despite good evidence demonstrating the utility of both approaches, data remain elusive as to whether EVLP is beneficial for all donor lungs prior to implantation, or instead as a tool by which we can evaluate and recondition sub-optimal donor lungs.

Donation After Circulatory Death Lungs Transplantable Up to Six Hours After Ex Vivo Lung Perfusion

BACKGROUND

Despite the critical need for donor lungs, logistic and geographic barriers hinder lung utilization. We hypothesized that lungs donated after circulatory death subjected to 6 hours of cold preservation after ex vivo lung perfusion (EVLP) would have similar outcomes after transplantation as lungs transplanted immediately after EVLP, and that both would perform superiorly compared with lungs transplanted immediately after procurement.

METHODS

Donor porcine lungs were procured after circulatory death and 15 minutes of warm ischemia. Three groups (n = 5 per group) were randomized: immediate left lung transplantation (Immediate group), EVLP for 4 hours followed by transplantation (EVLP group), or EVLP for 4 hours followed by 6 hours of cold preservation followed by transplantation (EVLP+Cold group). Lungs were reperfused for 2 hours before obtaining pulmonary vein samples for partial pressure of oxygen/fraction of inspired oxygen ratio calculations, airway pressures for compliance measurements, and wet/dry weight ratios.

RESULTS

The partial pressure of oxygen/fraction of inspired oxygen ratios in the EVLP and EVLP+Cold groups were significantly improved compared with those in the Immediate group (429.7 ± 51.8 and 436.7 ± 48.2 versus 117.4 ± 22.9 mm Hg, respectively). In addition, dynamic compliance was significantly improved in the EVLP and EVLP+Cold groups compared with immediate group (26.2 ± 4.2 and 27.9 ± 3.5 versus 11.1 ± 2.4 mL/cmH₂O, respectively). There were no differences in oxygenation capacity or dynamic compliance between the EVLP and EVLP+Cold groups. Inflammatory cytokine levels were significantly lower in the EVLP and EVLP+Cold groups.

CONCLUSIONS

Lungs donated after circulatory death can be successfully transplanted as much as 6 hours after EVLP. Cold preservation of lungs after ex vivo assessment and rehabilitation may improve organ allocation, even to distant recipients, without compromising allograft function.

A qualitative systematic review of the efficacy of sun protection education in organ transplant recipients

BACKGROUND

Transplant recipients are at increased risk of developing skin cancer as a result of chronic immunosuppression. Educating patients on sun protection has been routine posttransplantation, but to our knowledge, no systematic review has yet analyzed the efficacy of such education measures in this high-risk population.

OBJECTIVE

We sought to examine the efficacy of educating transplant recipients on skin cancer and sun protection.

METHODS

A literature search of interventional patient education studies published between January 1995 and March 2016 was performed in PubMed, CINAHL, Cochrane, and EMBASE databases.

RESULTS

Data from 7 studies meeting inclusion criteria were analyzed. No study attempted to examine the direct effect of sun protection education on skin cancer incidence in transplant recipients. Two randomized controlled trials showed that educational intervention can improve sun-protective behavior and decrease skin pigmentation or skin damage in sun-exposed areas. Three other randomized controlled trials compared the efficacy of 2 different forms of patient education at changing sun-protective behavior, but did not examine patient-oriented outcomes.

LIMITATIONS

A lack of high-quality randomized controlled trials with patient-oriented evidence and a dependence on self-reported data are limitations.

CONCLUSION

Sun protection education can be effective at altering patient behavior in transplant recipients, but its effect on posttransplantation skin cancer incidence remains to be elucidated.

Liver Allocation to Non-U.S. Citizen Non-U.S. Residents: An Ethical Framework for a Last-in-Line Approach

The incidence of non-U.S. citizen non-U.S. resident patients coming to the United States specifically for deceased donor liver transplantation raises compelling ethical questions that require careful consideration. The inclusion of these often financially and/or socially privileged patients in the pool of potential candidates for an absolutely scarce and life-saving liver transplant may exacerbate disparities already existing in deceased donor liver allocation. In addition, their inclusion on organ transplant waiting lists conflicts with recognized ethical principles of justice and reciprocity. Moreover, preliminary data suggest that public awareness of this practice could discourage organ donation, thereby worsening an already profound supply-demand gulf. Finally, U.S. organ allocation policies and statutes are out of step with recently promulgated international transplant guidelines, which prioritize self-sufficiency of organ programs. This article analyzes each of these ethical conflicts within the context of deceased donor liver transplantation and recommends policy changes that align the United States with international practices that discourage this scenario.

Short Stature and Access to Lung Transplantation in the United States. A Cohort Study

RATIONALE

Anecdotally, short lung transplant candidates suffer from long waiting times and higher rates of death on the waiting list compared with taller candidates.

OBJECTIVES

To examine the relationship between lung transplant candidate height and waiting list outcomes.

METHODS

We conducted a retrospective cohort study of 13,346 adults placed on the lung transplant waiting list in the United States between 2005 and 2011. Multivariable-adjusted competing risk survival models were used to examine associations between candidate height and outcomes of interest. The primary outcome was the time until lung transplantation censored at 1 year.

MEASUREMENTS AND MAIN RESULTS

The unadjusted rate of lung transplantation was 94.5 per 100 person-years among candidates of short stature (<162 cm) and 202.0 per 100 person-years among candidates of average stature (170-176.5 cm). After controlling for potential confounders, short stature was associated with a 34% (95% confidence interval [CI], 29-39%) lower rate of transplantation compared with average stature. Short stature was also associated with a 62% (95% CI, 24-96%) higher rate of death or removal because of clinical deterioration and a 42% (95% CI, 10-85%) higher rate of respiratory failure while awaiting lung transplantation.

CONCLUSIONS

Short stature is associated with a lower rate of lung transplantation and higher rates of death and respiratory failure while awaiting transplantation. Efforts to ameliorate this disparity could include earlier referral and listing of shorter candidates, surgical downsizing of substantially oversized allografts for shorter candidates, and/or changes to allocation policy that account for candidate height.

Broader Geographic Sharing of Pediatric Donor Lungs Improves Pediatric Access to Transplant

US pediatric transplant candidates have limited access to lung transplant due to the small number of donors within current geographic boundaries, leading to assertions that the current lung allocation system does not adequately serve pediatric patients. We hypothesized that broader geographic sharing of pediatric (adolescent, 12-17 years; child, <12 years) donor lungs would increase pediatric candidate access to transplant. We used the thoracic simulated allocation model to simulate broader geographic sharing. Simulation 1 used current allocation rules. Simulation 2 offered adolescent donor lungs across a wider geographic area to adolescents. Simulation 3 offered child donor lungs across a wider geographic area to adolescents. Simulation 4 combined simulations 2 and 3. Simulation 5 prioritized adolescent donor lungs to children across a wider geographic area. Simulation 4 resulted in 461 adolescent transplants per 100 patient-years on the waiting list (range 417-542), compared with 206 (range 180-228) under current rules. Simulation 5 resulted in 388 adolescent transplants per 100 patient-years on the waiting list (range 348-418) and likely increased transplant rates for children. Adult transplant rates, waitlist mortality, and 1-year posttransplant mortality were not adversely affected. Broader geographic sharing of pediatric donor lungs may increase pediatric candidate access to lung transplant.

Current state of clinical end-points assessment in transplant: Key points

Solid organ transplantation is the treatment of choice for patients with end-stage organ disease. However, organ transplantation can stress the cardiovascular system and decrease immune surveillance, leading to early mortality and graft loss due to multiple underlying comorbidities. Clinical end-points in transplant include death and graft failure. Thus, generating accurate predictive models through regression models is crucial to test for definitive clinical post-transplantation end-points. Survival predictive models should assemble efficient surrogate markers or prognostic factors to generate a minimal set of variables derived from a proper modeling strategy through regression models. However, a few critical points should be considered when reporting survival analyses and regression models to achieve proper discrimination and calibration of the predictive models. Additionally, population-based risk scores may underestimate risk prediction in transplant. The application of predictive models in these patients should therefore incorporate both classical and non-classical risk factors, as well as community-based health indicators and transplant-specific factors to quantify the outcomes in terms of survival properly. This review focuses on assessment of clinical end-points in transplant through regression models by combining predictive and surrogate variables, and considering key points in these analyses to accurately predict definitive end-points, which could aid clinicians in decision making.

Chronic lung allograft dysfunction: evolving practice

PURPOSE OF REVIEW

Chronic lung allograft dysfunction (CLAD) was recently introduced as an overarching term covering different phenotypes of chronic allograft dysfunction, including obstructive CLAD (bronchiolitis obliterans syndrome), restrictive CLAD (restrictive allograft syndrome) and graft dysfunction due to causes not related to chronic rejection. In the present review, we will highlight the latest insights and current controversies regarding the new CLAD terminology, underlying pathophysiologic mechanisms, diagnostic approach and possible treatment options.

RECENT FINDINGS

Different pathophysiological mechanisms are clearly involved in clinically distinct phenotypes of chronic rejection, as is reflected by differences in histology, allograft function and imaging. Therefore, not all CLAD patients may equally benefit from specific therapies.

SUMMARY

The recent introduction of CLAD importantly changed the clinical practice in lung transplant recipients. Given the relative low accuracy of the current diagnostic tools, future research should focus on specific biomarkers, more sensitive pulmonary function parameters and imaging techniques for timely CLAD diagnosis and phenotyping. Personalized or targeted therapeutic options for adequate prevention and treatment of CLAD are required.

Uterus transplantation: current progress and future prospects

Even if reproductive medicine has been remarkably successful during the past few decades, with the introduction of in vitro fertilization in the late 1970s and intracytoplasmic sperm injection in the early 1990s, it has been repeatedly mocked by infertility due to an absolute uterine factor. No treatment has been available for the women suffering from an absent or dysfunctional uterus, in terms of carrying a pregnancy. Approximately one in 500 women suffer from absolute uterine infertility, and the option so far to become a mother has been to either adopt or utilize gestational surrogacy. As of today, a total of eleven cases of human uterus transplantations have been reported worldwide, conducted in three different countries. The results of these initial experimental cases far exceed what might be expected of a novel surgical method. Many more uterus transplantations are to be expected in the near future, as other research teams' preparations are being ready to be put into clinical practice. In this review, we summarize the current worldwide experience of uterus transplantation as a treatment of absolute uterine factor infertility and the future prospects of human uterus transplantation.

The evolving potential for pediatric ex vivo lung perfusion

Despite the rise in the number of adult lung transplantations performed, rates of pediatric lung transplantation remain low. Lung transplantation is an accepted therapy for pediatric end-stage lung disease; however, it is limited by a shortage of donor organs. EVLP has emerged as a platform for assessment and preservation of donor lung function. EVLP has been adopted in adult lung transplantation and has successfully led to increased adult lung transplantations and donor lung utilization. We discuss the future implications of EVLP utilization, specifically, its potential evolving role in overcoming donor shortages in smaller children and adolescents to improve the quality and outcomes of lung transplantation in pediatric patients.

Cell-Free DNA: An Upcoming Biomarker in Transplantation

After organ transplantation, donor-derived cell-free DNA (ddcfDNA) can be detected in the recipient's blood and urine. Different ddcfDNA quantification techniques have been investigated but a major breakthrough was made with the introduction of digital droplet PCR and massive parallel sequencing creating the opportunity to increase the understanding of ddcfDNA kinetics after transplantation. The observations of increased levels of ddcfDNA during acute rejection and even weeks to months before histologic features of graft rejection point to a possible role of ddcfDNA as an early, noninvasive rejection marker. In this review, we summarize published research on ddcfDNA in the transplantation field thereby elaborating on its clinical utility.

Mechanical circulatory support in lung transplantation: Cardiopulmonary bypass, extracorporeal life support, and ex-vivo lung perfusion

Lung transplant is the standard of care for patients with end-stage lung disease refractory to medical management. There is currently a critical organ shortage for lung transplantation with only 17% of offered organs being transplanted. Of those patients receiving a lung transplant, up to 25% will develop primary graft dysfunction, which is associated with an 8-fold increase in 30-d mortality. There are numerous mechanical lung assistance modalities that may be employed to help combat these challenges. We will discuss the use of mechanical lung assistance during lung transplantation, as a bridge to transplant, as a treatment for primary graft dysfunction, and finally as a means to remodel and evaluate organs deemed unsuitable for transplant, thus increasing the donor pool, improving survival to transplant, and improving overall patient survival.