Effect of Including Important Clinical Variables on Accuracy of the Lung Allocation Score for Cystic Fibrosis and Chronic Obstructive Pulmonary Disease

Association of the initial implementation of continuous distribution allocation policy with outcomes for lung transplant candidates by blood type

On March 9, 2023, allocation of donor lungs in the United States changed to continuous distribution (CD). Initial implementation of policy was flawed due to a programming error affecting priority of candidates by blood type. Although this issue has been identified and addressed, the impact of initial policy implementation on blood type-O candidates has not been rigorously evaluated. We used data from the Scientific Registry of Transplant Recipients to evaluate candidate (n = 4738) and recipient (n = 4437) outcomes following CD policy implementation. Using cumulative incidence plots accounting for competing risks and multivariable Cox models, incidence of transplantation prepolicy was similar by blood type (8-month incidence 81.0% vs 80.5% for blood types-A, B, or AB and blood type-O, respectively, P = .57). Following CD policy, blood type-O candidates had lower incidence of transplantation relative to other blood types (8-month incidences 86.3% vs 92.1%, respectively, P < .001), with a significantly lower adjusted hazard ratio for transplantation (0.67; 95% confidence interval, 0.54-0.82). Blood type-O candidates were more likely Hispanic and 'Other' race and had higher rates of waitlist removal or death following CD (6.0% vs 2.9%, P = .003). Among transplants performed prior to CD, 48% were blood type-O recipients compared to 40% post-CD, representing 138 fewer blood type-O transplants than expected. Type-O blood candidates had significant decline in prognosis relative to other blood groups following initial implementation of CD policy.

Paediatric Lung Transplantation for Childhood Interstitial Lung Disease: Indications and Outcome

BACKGROUND

Childhood interstitial lung disease (chILD) is heterogeneous, associated with significant morbidity and can cause organ failure. In these cases, lung transplantation (LuTx) is a treatment option. Data on indications and outcome after LuTx for chILD is limited. We compared characteristics of LuTx for chILD to the indications cystic fibrosis (CF) and pulmonary hypertension (PH).

METHODS

chILD-patients <18 years who underwent LuTx at our center between Jan 1st, 2011 and Sep 30th, 2023, were retrospectively analysed and divided into two groups depending on their age at disease manifestation: Children in the chILD A group predominantly became ill during the first two years of life, chILD B patients thereafter. Outcomes were compared to patients with CF and PH.

RESULTS

101 children were included (chILD A 12; chILD B 19; CF 49; PH 21). Patients in the chILD A group were younger (mean age 1.5 vs., 12.9, 15.2, 10.9 years) and frequently required mechanical ventilation before LuTx (41.7%, vs. 10.5%, 2%, 9.5%, respectively). Their median ICU stay (23 vs. 4, 2, 13 days) and median hospital stay (48 vs. 27, 30, 42 days) after LuTx was longer. Patients with chILD B had the lowest pre-transplant ICU requirement (21.1% vs. 66.7% for chILD A, 30.6% for CF and 47.6% for PH) and short median hospital stay. Five year survival was comparable in all groups (80.2%, 86.5%, 80.4%, and 81.2%).

CONCLUSION

LuTx for patients with chILD shows favourable outcome, although younger chILD A patients had a higher pre-transplant morbidity and longer ICU and hospital stay surrounding the transplantation.

Process and validity of linking cystic fibrosis patient registry with national Medicaid databases

BACKGROUND

The Cystic Fibrosis Foundation Patient Registry (CFFPR) provides valuable clinical and demographic data but includes limited information on health services and medications provided outside of CF Care Centers. Linking CFFPR to claims databases such as national Medicaid data could address these data gaps.

METHODS

Linkage algorithms based on state of residence, gender, and date of birth were utilized to match individuals with CF diagnostic codes in national Medicaid databases (2016) to individuals in the CFFPR (2015-2016). Subsets of individuals with partial social security numbers or residing in the state of North Carolina were utilized to validate the accuracy of linkages and perform exploratory analyses on care utilization and costs.

RESULTS

Of the 32,152 individuals in CFFPR, 10,616 were uniquely linked to national Medicaid databases. The 372 linked individuals within the NC extract had 8.0 ± 7.6 visits to outpatient providers, substantially higher than the 4.2 ± 2.4 CF Care Center outpatient visits documented within CFFPR. Similarly, linked individuals had 2.1 ± 1.7 oral antibiotic prescriptions within CMS pharmacy databases versus 0.5 ± 1.9 oral antibiotic prescriptions in CFFPR. Total pharmacy costs for the linked individuals in NC were $16.4 million, with pancrealipase (19 %), dornase alfa (24 %), and CFTR modulators (29 %) the largest expenditures. Total non-pharmacy costs were $7.5 million, with inpatient hospitalization representing 53 % of costs.

CONCLUSION

Linkage of data from Medicaid and CFFPR can produce valid comprehensive data on low-income people with CF and provide opportunities to examine utilization/adherence or comparative effectiveness and safety of medications as well as conduct economic analyses in the low-income CF population.

Linkage of the CF Foundation Patient Registry with the Scientific Registry of Transplant Recipients database

BACKGROUND

The Cystic Fibrosis Foundation Patient Registry (CFFPR) maintains clinical data, including history of solid organ transplant, on people with cystic fibrosis (CF) who obtain care at CF Foundation-accredited care centers. The Scientific Registry of Transplant Recipients (SRTR) database is a collection of national data related to organ transplantation that supports research to evaluate solid organ transplant candidate and recipient outcomes.

METHODS

Individuals in the CFFPR were matched to SRTR records using an algorithm that compared names, last four digits of social security numbers, date of birth and date of death. We evaluated match quality by summarizing the extent to which transplant status agreed between the two data sources by organ and year of listing or transplant. We summarized CFFPR-reported characteristics for lung and liver transplants in the year prior to transplant.

RESULTS

A total of 7,594 individuals who participated in the CFFPR matched SRTR records with approximately 75% having at least one transplant record in SRTR. Over 97% of the matched population had a CF diagnosis reported to SRTR. In total, 5,253 people were identified as lung transplant recipients and 499 as liver transplant recipients in SRTR. Clinical characteristics for lung and liver transplants were consistent with the epidemiology of transplantation for people with CF.

CONCLUSIONS

Linkage of the two data sources was successful, with high agreement between them supporting the use of the matched population as a valid resource to study transplantation in CF, particularly leveraging pre-transplant characteristics (collected in CFFPR) with detailed transplant data (collected in SRTR).

Cell-Free DNA Maps Tissue Injury and Correlates with Disease Severity in Lung Transplant Candidates

Rationale: Plasma cell-free DNA levels correlate with disease severity in many conditions. Pretransplant cell-free DNA may risk stratify lung transplant candidates for post-transplant complications. Objectives: To evaluate if pretransplant cell-free DNA levels and tissue sources identify patients at high risk of primary graft dysfunction and other pre- and post-transplant outcomes. Methods: This multicenter, prospective cohort study recruited 186 lung transplant candidates. Pretransplant plasma samples were collected to measure cell-free DNA. Bisulfite sequencing was performed to identify the tissue sources of cell-free DNA. Multivariable regression models determined the association between cell-free DNA levels and the primary outcome of primary graft dysfunction and other transplant outcomes, including Lung Allocation Score, chronic lung allograft dysfunction, and death. Measurements and Main Results: Transplant candidates had twofold greater cell-free DNA levels than healthy control patients (median [interquartile range], 23.7 ng/ml [15.1-35.6] vs. 12.9 ng/ml [9.9-18.4]; P < 0.0001), primarily originating from inflammatory innate immune cells. Cell-free DNA levels and tissue sources differed by native lung disease category and correlated with the Lung Allocation Score (P < 0.001). High pretransplant cell-free DNA increased the risk of primary graft dysfunction (odds ratio, 1.60; 95% confidence interval [CI], 1.09-2.46; P = 0.0220), and death (hazard ratio, 1.43; 95% CI, 1.07-1.92; P = 0.0171) but not chronic lung allograft dysfunction (hazard ratio, 1.37; 95% CI, 0.97-1.94; P = 0.0767). Conclusions: Lung transplant candidates demonstrate a heightened degree of tissue injury with elevated cell-free DNA, primarily originating from innate immune cells. Pretransplant plasma cell-free DNA levels predict post-transplant complications.

Standards for the care of people with cystic fibrosis (CF); recognising and addressing CF health issues

This is the third in a series of four papers updating the European Cystic Fibrosis Society (ECFS) standards for the care of people with CF. This paper focuses on recognising and addressing CF health issues. The guidance was produced with wide stakeholder engagement, including people from the CF community, using an evidence-based framework. Authors contributed sections, and summary statements which were reviewed by a Delphi consultation. Monitoring and treating airway infection, inflammation and pulmonary exacerbations remains important, despite the widespread availability of CFTR modulators and their accompanying health improvements. Extrapulmonary CF-specific health issues persist, such as diabetes, liver disease, bone disease, stones and other renal issues, and intestinal obstruction. These health issues require multidisciplinary care with input from the relevant specialists. Cancer is more common in people with CF compared to the general population, and requires regular screening. The CF life journey requires mental and emotional adaptation to psychosocial and physical challenges, with support from the CF team and the CF psychologist. This is particularly important when life gets challenging, with disease progression requiring increased treatments, breathing support and potentially transplantation. Planning for end of life remains a necessary aspect of care and should be discussed openly, honestly, with sensitivity and compassion for the person with CF and their family. CF teams should proactively recognise and address CF-specific health issues, and support mental and emotional wellbeing while accompanying people with CF and their families on their life journey.

ESPEN-ESPGHAN-ECFS guideline on nutrition care for cystic fibrosis

BACKGROUND

Nutritional status is paramount in Cystic Fibrosis (CF) and is directly correlated with morbidity and mortality. The first ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with CF were published in 2016. An update to these guidelines is presented.

METHODS

The study was developed by an international multidisciplinary working group in accordance with officially accepted standards. Literature since 2016 was reviewed, PICO questions were discussed and the GRADE system was utilized. Statements were discussed and submitted for on-line voting by the Working Group and by all ESPEN members.

RESULTS

The Working Group updated the nutritional guidelines including assessment and management at all ages. Supplementation of vitamins and pancreatic enzymes remains largely the same. There are expanded chapters on pregnancy, CF-related liver disease, and CF-related diabetes, bone disease, nutritional and mineral supplements, and probiotics. There are new chapters on nutrition with highly effective modulator therapies and nutrition after organ transplantation.

Lung Allocation Score Exceptions in Persons with Cystic Fibrosis Undergoing Lung Transplant

Rationale: Lung transplantation can extend the lives of individuals with advanced cystic fibrosis (CF). Until March 2023, the Lung Allocation Score (LAS) was used in the United States to determine transplant priority. Certain clinical events or attributes ("risk events") that are not included in the LAS (e.g., massive hemoptysis) are relatively common and prognostically important in CF and may prompt an exception request to increase priority for donor lungs. The new Lung Composite Allocation Score (CAS) also allows for exceptions based on the same principles. Objectives: To evaluate the frequency of LAS exceptions in persons with CF (PwCFs) listed for lung transplantation and assess whether LAS exceptions are associated with improved waitlist outcomes for PwCFs compared with similarly "at-risk" individuals without LAS exceptions. Methods: A merged dataset combining data from the CF Foundation Patient Registry and the Organ Procurement and Transplantation Network (2005-2019) was used to identify PwCFs listed for lung transplantation. We compared waitlist outcomes between PwCFs with a LAS exception versus those without an exception despite having a risk event. Risk events were defined as an episode of massive hemoptysis, pneumothorax, at least three moderate/severe pulmonary exacerbations, and/or a decrease in forced expiratory volume in 1 second by ⩾30% predicted (absolute) in the prior 12 months. Analyses were performed using competing risk regression with time to transplantation as the primary outcome and death without a transplant as a competing risk. Results: Of 3,538 listings from 3,309 candidates, 2% of listings (n = 81) had at least one exception. Candidates with an exception and those with a risk event but no exception received lung transplants more slowly than people without an exception or risk event (subdistribution hazard ratio [95% confidence interval]: LAS exception cohort, 0.66 [0.52-0.85]; risk event cohort without exceptions, 0.79 [0.72-0.86]). There was no difference between those with LAS exceptions and those at risk without LAS exceptions: subdistribution hazard ratio, 0.84 (0.66-1.08). Conclusions: LAS exceptions are rare in PwCFs listed for lung transplantation. LAS exceptions resulted in a similar time to transplantation for PwCFs compared with similarly at-risk individuals. As we enter the CAS era, these LAS-based results are pertinent to improve risk stratification among PwCFs being considered for lung transplantation.

Lung Transplantation in a New Era in the Field of Cystic Fibrosis

Lung transplantation for people with cystic fibrosis (PwCF) is a critical therapeutic option, in a disease without a cure to this day, and its overall success in this population is evident. The medical advancements in knowledge, treatment, and clinical care in the field of cystic fibrosis (CF) rapidly expanded and improved over the last several decades, starting from early pathology reports of CF organ involvement in 1938, to the identification of the CF gene in 1989. Lung transplantation for CF has been performed since 1983, and CF now accounts for about 17% of pre-transplantation diagnoses in lung transplantation recipients. Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have been the latest new therapeutic modality addressing the underlying CF protein defect with the first modulator, ivacaftor, approved in 2012. Fast forward to today, and we now have a growing CF population. More than half of PwCF are now adults, and younger patients face a better life expectancy than they ever did before. Unfortunately, CFTR modulator therapy is not effective in all patients, and efficacy varies among patients; it is not a cure, and CF remains a progressive disease that leads predominantly to respiratory failure. Lung transplantation remains a lifesaving treatment for this disease. Here, we reviewed the current knowledge of lung transplantation in PwCF, the challenges associated with its implementation, and the ongoing changes to the field as we enter a new era in the care of PwCF. Improved life expectancy in PwCF will surely influence the role of transplantation in patient care and may even lead to a change in the demographics of which people benefit most from transplantation.

The intersection of race and ethnicity, gender, and primary diagnosis on lung transplantation outcomes

BACKGROUND

Reducing racial disparities in lung transplant outcomes is a current priority of providers, policymakers, and lung transplant centers. It is unknown how the combined effect of race and ethnicity, gender, and diagnosis group is associated with differences in 1-year mortality and 5-year survival.

METHODS

This is a longitudinal cohort study using Standard Transplant Analysis Research files from the United Network for organ sharing. A total of 25,444 patients undergoing first time lung transplantation between 2006 and 2019 in the United States. The primary exposures were lung transplant recipient race and ethnicity, gender, and primary diagnosis group at listing. Multivariable regression models and cox-proportional hazards models were used to determine adjusted 1-year mortality and 5-year survival.

RESULTS

Overall, 25,444 lung transplant patients were included in the cohort including 15,160 (59.6%) men, 21,345 (83.9%) White, 2,318 (9.1%), Black and Hispanic/Latino (7.0%). Overall, men had a significant higher 1-year mortality than women (11.87%; 95% CI 11.07-12.67 vs 12.82%; 95% CI 12.20%-13.44%). Black women had the highest mortality of all race and gender combinations (14.51%; 95% CI 12.15%-16.87%). Black patients with pulmonary vascular disease had the highest 1-year mortality (19.77%; 95% CI 12.46%-27.08%) while Hispanic/Latino patients with obstructive lung disease had the lowest (7.42%; 95% CI 2.8%-12.05%). 5-year adjusted survival was highest among Hispanic/Latino patients (62.32%) compared to Black (57.59%) and White patients (57.82%).

CONCLUSIONS

There are significant differences in 1-year and 5-year mortality between and within racial and ethnic groups depending on gender and primary diagnosis. This demonstrates the impact of social and clinical factors on lung transplant outcomes.

Diagnosis and Management of Cystic Fibrosis Exacerbations

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is acute pulmonary exacerbation (PEx). Clinical and microbial epidemiology studies of CF PEx continue to provide important insight into the disease course, prognosis, and complications. This work has now led to several large-scale clinical trials designed to clarify the treatment paradigm for CF PEx. The primary goal of this review is to provide a summary and update of the pathophysiology, clinical and microbial epidemiology, outcome and treatment of CF PEx, biomarkers for exacerbation, and the impact of highly effective modulator therapy on these events moving forward.

The Lung Transplant Candidate, Indications, Timing, and Selection Criteria

Lung transplantation can be lifesaving for patients with advanced lung disease. Demographics are evolving with recipients now sicker but determining candidacy remains predicated on one's underlying lung disease prognosis, along with the likelihood of posttransplant success. Determining optimal timing can be challenging, and most programs favor initiating the process early and proactively to allow time for patient education, informed decision-making, and preparation. A comprehensive, multidisciplinary evaluation is used to elucidate disease progrnosis and identify risk factors for poor posttransplant outcomes. Candidacy criteria vary significantly by center, and close communication between referring and transplant providers is necessary to improve access to transplant and outcomes.

The Lung Allocation Score Remains Inequitable for Patients with Pulmonary Arterial Hypertension, Even after the 2015 Revision

Rationale: The lung allocation score (LAS) was revised in 2015 to improve waiting list mortality and rate of transplant for patients with pulmonary arterial hypertension (PAH). Objectives: We sought to determine if the 2015 revision achieved its intended goals. Methods: Using the Standard Transplant Analysis and Research file, we assessed the impact of the 2015 LAS revision by comparing the pre- and postrevision eras. Registrants were divided into the LAS diagnostic categories: group A-chronic obstructive pulmonary disease; group B-pulmonary arterial hypertension; group C-cystic fibrosis; and group D-interstitial lung disease. Competing risk regressions were used to assess the two mutually exclusive competing risks of waiting list death and transplant. Cumulative incidence plots were created to visually inspect risks. Measurements and Main Results: The LAS at organ matching increased by 14.2 points for registrants with PAH after the 2015 LAS revision, the greatest increase among diagnostic categories (other LAS categories: Δ, -0.9 to +2.8 points). Before the revision, registrants with PAH had the highest risk of death and lowest likelihood of transplant. After the 2015 revision, registrants with PAH still had the highest risk of death, now similar to those with interstitial lung disease, and the lowest rate of transplant, now similar to those with chronic obstructive pulmonary disease. Conclusions: Although the 2015 LAS revision improved access to transplant and reduced the risk of waitlist death for patients with PAH, it did not go far enough. Significant differences in waitlist mortality and likelihood of transplant persist.

Hemoptysis and the Risk for Lung Transplant or Death without Transplant in Individuals with Cystic Fibrosis in the United States

Rationale: Hemoptysis is a common and important complication in persons with cystic fibrosis (PwCF). Despite this, there is limited literature on the impact of hemoptysis on contemporary cystic fibrosis (CF) outcomes. Objectives: Evaluate whether hemoptysis increases the risk of lung transplant or death without a transplant in PwCF. Methods: We reviewed a dataset of PwCF ages 12 years or older from the CFFPR (CF Foundation Patient Registry) that included 29,587 individuals. We identified hemoptysis as our predictor of interest and categorized PwCF as either no hemoptysis, any hemoptysis (submassive and/or massive), or massive hemoptysis. We subsequently evaluated whether hemoptysis, as defined above, was associated with death without transplant or receipt of lung transplant via logistic regression. We adjusted for age, sex, body mass index, forced expiratory volume in one second (FEV1), number of exacerbations, supplemental oxygen use, CF-related diabetes, and Pseudomonas aeruginosa colonization status. Subgroup analyses were performed in advanced lung disease, defined as PwCF with an FEV1 <40% predicted. Results: PwCF with any form of hemoptysis were more likely to progress to lung transplant or die without transplant than PwCF who did not have hemoptysis (odds ratio [OR], 1.3 [95% confidence interval (CI), 1.1-1.7]). The effect size of these associations was larger when hemoptysis events were classified as "massive" (massive hemoptysis OR, 2.2 [95% CI, 1.2-3.8]) or in PwCF with advanced lung disease (massive hemoptysis in advanced lung disease OR, 3.2 [95% CI 1.3-8.2]). Conclusions: Hemoptysis is associated with an increased risk of lung transplant and death without a transplant in PwCF, especially among those with massive hemoptysis or advanced lung disease. Our results suggest that hemoptysis functions as a useful predictor of serious outcomes in PwCF and may be important to incorporate into risk prediction models and/or transplant decisions in CF.

Development and Internal Validation of a Prognostic Model of the Probability of Death or Lung Transplantation Within 2 Years for Patients With Cystic Fibrosis and FEV1 ≤ 50% Predicted

BACKGROUND

Improved methods are needed to risk-stratify patients with cystic fibrosis (CF) and reduced FEV1.

RESEARCH QUESTIONS

What are the predictors of death or lung transplantation (LTx) within 2 years among patients with CF whose FEV1 ≤ 50% predicted? Do these markers similarly predict outcomes among G551D patients taking ivacaftor since 2012?

STUDY DESIGN AND METHODS

Patients with CF, age ≥ 6 years with FEV1 ≤ 50% predicted as of December 31, 2014, were identified in a data set that merged Cystic Fibrosis Foundation and United Network for Organ Sharing (UNOS) registries. The least absolute shrinkage and selection operator (LASSO) method was applied to a randomly selected training set to select important prognostic variables. Accuracy and association of the model with death or LTx with 2 years (2-year death or LTx) were validated via logistic regression on an independent test set. Sensitivity analyses explored predictors for patients with UNOS data.

RESULTS

FEV1 percent predicted (OR, 1.51 for 5% decrease; 95% CI, 1.27-1.81), number of pulmonary exacerbations treated with IV antibiotics (OR, 1.35; 95% CI, 1.11-1.65), and continuous or nocturnal oxygen (OR, 3.71; 95% CI, 1.81-7.59) were significantly associated with 2-year death or LTx. Our model predicted outcomes with greater sensitivity (ratio of sensitivity, 1.26; 95% CI, 1.02-1.54), ratio of positive predictive value (1.25; 95% CI, 1.05-1.51), and ratio of negative predictive value (1.04; 95% CI, 1.01-1.07) than FEV1 < 30% predicted. Among those taking ivacaftor in 2014, only FEV1 remained associated with 2-year death or LTx. For patients with UNOS data, LASSO identified additional covariates of interest, including noninvasive ventilation use, low hemoglobin, pulmonary arterial systolic pressure, supplemental oxygen, mechanical ventilation, FEV1 percent predicted, and cardiac index.

INTERPRETATION

Among individuals with CF and FEV1 ≤ 50% predicted, FEV1 percent predicted, oxygen therapy, and number of pulmonary exacerbations predicted 2-year death or LTx. Although limited by small sample size, only FEV1 remained predictive in patients receiving highly effective modulator therapy. Additional physiologic variables could improve prognostication in CF.

Limitations of the dichotomized 6-minute walk distance when computing lung allocation score for cystic fibrosis: a 16-year retrospective cohort study

PURPOSE

The 2010 Lung Allocation Score (LAS) version considers the estimated survival benefit offered by lung transplantation (LTx) and uses 6-minute Walk Test (6MWT) distance as a dichotomous covariate of whether an individual can walk more than 150 ft or 45.7 m in 6 min. This study aimed to provide evidence that 6MWT gives no clinically meaningful information to be used in the current LAS for candidates to LTx with cystic fibrosis (CF).

MATERIALS AND METHODS

We collected data from 6MWTs performed since 2003 at our CF centre. A joint model was fitted to describe the effect of changes in walked distance on the hazard of LTx or death.

RESULTS

Up to 2019, 552 6MWTs were performed on 163 individuals with CF. None of the individuals included walked for less than 45.7 m during the 6MWT. Based on the joint modelling, the association of walked distance with the hazard ratio (HR) of LTx or death was significant (HR 0.99, 95% Credible Interval [CI]: 0.99 to 1.00).

CONCLUSIONS

When adopted dichotomously for LAS calculation, walked distance does not add any useful information about exercise capacity. Longitudinal trajectories of walked distance may provide complementary information about prognosis in individuals with CF.Implications for rehabilitationDichotomized walked distance does not contribute to lung allocation score in candidates to lung transplantation with cystic fibrosisChanges in the longitudinal trajectory of walked distance can be clinically meaningful for prognostication.Sensitive outcomes to be incorporated in the lung allocation scoring system for individuals with CF are yet needed to catch rapid falls in functional capacity.

Cystic fibrosis: candidate selection and impact of the cystic fibrosis transmembrane conductance regulator therapy

PURPOSE OF REVIEW

Over the past decade, the development of highly effective cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators has dramatically ameliorated the manifestations of CF for most patients. Perhaps most importantly, CFTR modulators impact the development and progression of advanced lung disease (ALD) and are changing the CF population accessing lung transplant.

RECENT FINDINGS

A recent phase 3 trial of elexacaftor/tezacaftor/ivacaftor (ETI) demonstrated efficacy for individuals with at least one copy of the most common CF mutation, F508del. Studies of CFTR modulator therapy in patients with ALD have demonstrated similar improvements in lung function, nutrition, and pulmonary exacerbation frequency as seen in individuals with higher lung function. Due to improvements with ETI, rates of lung transplant for CF have declined and individuals are achieving stability in lung function. Nevertheless, the Cystic Fibrosis Foundation guidelines for lung transplant referral should be used to guide referral decisions for all individuals with CF, including those on CFTR modulator therapy, to allow remediation of modifiable barriers to transplant. ETI may be used in the posttransplant setting but for selected individuals and with close monitoring.

SUMMARY

Increasing access to highly effective CFTR modulators has changed the trajectory of lung disease in CF for many, but not all, individuals and there remain individuals who cannot access therapy or whose mutations do not respond to modulators. Lung transplant remains an important treatment option for individuals with advanced CF lung disease. Increasing attention will be required to optimize decisions of when to list for transplant.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

Waiting List Dynamics and Lung Transplantation Outcomes After Introduction of the Lung Allocation Score in The Netherlands

Supplemental Digital Content is available in the text.

The Netherlands was the third country to adopt the lung allocation score (LAS) for national allocation of donor lungs in April 2014. Evaluations of the introduction of the LAS in the United States and Germany showed mainly beneficial effects, including increased survival after transplantation.

The impact of the high emergency lung transplantation program in cystic fibrosis in France: insight from a comparison with Canada

INTRODUCTION

France implemented a high emergency lung transplantation (HELT) program nationally in 2007. A similar program does not exist in Canada. The objectives of our study were to compare health outcomes within France as well as between Canada and France before and after the HELT program in a population with Cystic Fibrosis (CF).

METHODS

This population-based cohort study utilised data from the French and Canadian CF registries. A cumulative incidence curve assessed time to transplant with death without transplant as competing risks. The Kaplan-Meier method was used to estimate post-transplant survival.

RESULTS

Between 2002 and 2016, there were 1075 (13.0%) people with CF in France and 555 (10.2%) people with CF in Canada who underwent lung transplantation. The proportion of lung transplant increased in France after the HELT program was initiated (4.5% versus 10.1%) whereas deaths pre-transplant decreased from 85.3% in the pre-HELT to 57.1% in the post-HELT period. Between 2008-2016, people in France were significantly more likely to receive a transplant (Hazard Ratio (HR) 1.56, 95% CI 1.37-1.77, p<0.001) than die (HR 0.55, 95% CI 0.46-0.66, p<0.001) compared to Canada. Post-transplant survival was similar between the countries and there was no difference in survival when comparing pre- and post-HELT period in France.

CONCLUSION

Following the implementation of the HELT program, people living with CF in France were more likely to receive a transplant than die. Post-transplant survival in the post-HELT period in France did not change compared to the pre-HELT period, despite potentially sicker patients being transplanted, and is comparable to Canada.

The Impact of Resistant Bacterial Pathogens including Pseudomonas aeruginosa and Burkholderia on Lung Transplant Outcomes

Pseudomonas and Burkholderia are gram-negative organisms that achieve colonization within the lungs of patients with cystic fibrosis, and are associated with accelerated pulmonary function decline. Multidrug resistance is a hallmark of these organisms, which makes eradication efforts difficult. Furthermore, the literature has outlined increased morbidity and mortality for lung transplant (LTx) recipients infected with these bacterial genera. Indeed, many treatment centers have considered Burkholderia cepacia infection an absolute contraindication to LTx. Ongoing research has delineated different species within the B. cepacia complex (BCC), with significantly varied morbidity and survival profiles. This review considers the current evidence for LTx outcomes between the different subspecies encompassed within these genera as well as prophylactic and management options. The availability of meta-genomic tools will make differentiation between species within these groups easier in the future, and will allow more evidence-based decisions to be made regarding suitability of candidates colonized with these resistant bacteria for LTx. This review suggests that based on the current evidence, not all species of BCC should be considered contraindications to LTx, going forward.

Bridging the survival gap in cystic fibrosis: An investigation of lung transplant outcomes in Canada and the United States

BACKGROUND

Previous literature in cystic fibrosis (CF) has shown a 10-year survival gap between Canada and the United States (US). We hypothesized that differential access to and survival after lung transplantation may contribute to the observed gap. The objectives of this study were to compare CF transplant outcomes between Canada and the US and estimate the potential contribution of transplantation to the survival gap.

METHODS

Data from the Canadian CF Registry and the US Cystic Fibrosis Foundation Patient Registry supplemented with data from United Network for Organ Sharing were used. The probability of surviving after transplantation between 2005 and 2016 was calculated using the Kaplan‒Meier method. Survival by insurance status at the time of transplantation and transplant center volume in the US were compared with those in Canada using Cox proportional hazard models. Simulations were used to estimate the contribution of transplantation to the survival gap.

RESULTS

Between 2005 and 2016, there were 2,653 patients in the US and 470 in Canada who underwent lung transplantation for CF. The 1-, 3-, and 5-year survival rates were 88.3%, 71.8%, and 60.3%, respectively, in the US compared with 90.5%, 79.9%, and 69.7%, respectively, in Canada. Patients in the US were also more likely to die on the waitlist (p < 0.01) than patients in Canada. If the proportion of who underwent transplantation and post-transplant survival in the US were to increase to those observed in Canada, we estimate that the survival gap would decrease from 10.8 years to 7.5 years.

CONCLUSIONS

Differences in waitlist mortality and post-transplant survival can explain up to a third of the survival gap observed between the US and Canada.

Lung transplantation: a review of the optimal strategies for referral and patient selection

One of the great challenges of lung transplantation is to bridge the dichotomy between supply and demand of donor organs so that the maximum number of potential recipients achieve a meaningful benefit in improvements in survival and quality of life. To achieve this laudable goal is predicated on choosing candidates who are sufficiently unwell, in fact possessing a terminal respiratory illness, but otherwise fit and able to undergo major surgery and a prolonged recuperation and rehabilitation stage combined with ongoing adherence to complex medical therapies. The choice of potential candidate and the timing of that referral is at times perhaps more art than science, but there are a number of solid guidelines for specific illnesses to assist the interested clinician. In this regard, the relationship between the referring clinician and the lung transplant unit is a critical one. It is an ongoing and dynamic process of education and two way communication, which is a marker of the professionalism of a highly performing unit. Lung transplantation is ultimately a team effort where the recipient is the key player. That principle has been enshrined in the three consensus position statements regarding selection criteria for lung and heart-lung transplantation promulgated by the International Society for Heart and Lung Transplantation over the last two decades. During this period, the number of indications for lung transplantation have broadened and the number of contraindications reduced. Risk management is paramount in the pre- and perioperative period to effect early successful outcomes. While it is not the province of this review to reiterate the detailed listing of those factors, an overview position will be developed that describes the rationale and evidence for selected criteria where that exists. Importantly, the authors will attempt to provide an historical and experiential basis for making these important and life-determining decisions.

The reviews of this paper are available via the supplementary material section.

Acute Pulmonary Exacerbations in Cystic Fibrosis

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is an acute pulmonary exacerbation. Clinical and microbial epidemiology studies of CF pulmonary exacerbations continue to provide important insight into the disease course, prognosis, and complications. This work has now led to a number of large scale clinical trials with the goal of improving the treatment paradigm for CF pulmonary exacerbation. The primary goal of this review is to provide a summary of the pathophysiology, the clinical epidemiology, microbial epidemiology, outcome and the treatment of CF pulmonary exacerbation.