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

Increased Donor Organ Size and Age is Associated with Reduced Survival in Female Lung Transplant Recipients

BACKGROUND

Organ selection in lung transplantation (LTx) is still controversial. We here analyze the impact of mismatches in size, age, and gender on early and long-term outcome after LTx.

METHODS

Retrospective analysis of donor and recipient characteristics of patients who underwent double LTx between March 2003 and December 2021. Statistical analysis was performed using SPSS and GraphPad software.

RESULTS

Two hundred three patients were included (94 women and 109 men). In the whole cohort, oversizing donor organs 10% to 20% compared to the recipients' predicted total lung capacity led to a decreased incidence of severe Primary Graft Dysfunction grades 2 and 3 (2/3; 15% vs 41%, P = .03), and further oversizing > 20% was associated with reduced long-term survival (hazard ratio, 2.33, P = .011). Analyzing donor and recipient age, we found that increased donor age correlated with reduced long-term survival (P = .013). In this cohort, female recipients received older organs (median 57 vs 46 years, P = .0003) and had a higher incidence of > 20% oversizing (13% vs 4%, P = .019) of donor lungs, which resulted in a significantly reduced long-term survival (P = .02) compared with male recipients. Median Lung Allocation Scores were similar in both groups.

CONCLUSION

Mismatch of donor age and size can be important for organ function and survival in LTx recipients. Particularly female recipients seem to have a higher risk for unfavorable long-term outcome when transplanting organs of increased size and age. Multicenter studies are warranted to further address this question.

TRIAL REGISTRATION NUMBER

(DKRS): 00033312.

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.

Sarcoidosis lung transplantation waitlist mortality, a national registry database study

Background

The Lung Allocation Score (LAS) prioritises lung transplantation candidates, balancing waitlist mortality and post-transplant survival. The score groups sarcoidosis candidates based on mean pulmonary artery pressure: those with ≤30 mmHg (sarcoidosis A) are grouped with COPD and those with >30 mmHg (sarcoidosis D) with idiopathic pulmonary fibrosis (IPF). We hypothesise that sarcoidosis candidates have a higher waitlist mortality than other candidates within their LAS grouping.

Methods

This is a retrospective cohort study of consecutive lung transplantation candidates from the Scientific Registry of Transplant Recipients database from May 2005 to May 2019. We included candidates aged ≥18 years diagnosed with sarcoidosis, COPD or IPF. Univariate, multivariate and survival estimate analyses were performed.

Results

We identified 385 sarcoidosis A, 642 sarcoidosis D, 7081 COPD and 10 639 IPF lung transplantation candidates. 17.3% of sarcoidosis D, 14.8% of IPF, 14.3% of sarcoidosis A and 9.8% of COPD candidates died awaiting transplant. Sarcoidosis A was an independent risk factor for waitlist mortality. Sarcoidosis A had a lower waitlist survival probability compared to COPD. Sarcoidosis D had the highest waitlist mortality. IPF candidates had lower waitlist survival probability than sarcoidosis D in the first 60 days after listing.

Conclusion

Based on our results, the grouping of candidates with sarcoidosis in allocation systems should be revised to mitigate waitlist mortality disparity.

Social and biologic determinants in lung transplant allocation

PURPOSE OF REVIEW

Lung transplant is a life-saving intervention for many with end-stage lung disease. As usable donor lungs are a limited resource and the risk of death on the waitlist is not uniform among candidates, organ allocation must consider many variables in order to be equitable.

RECENT FINDINGS

The lung allocation score (LAS) system, implemented in 2005, accounted for disease severity, risk of death without transplant, and 1-year survival estimates; however, recipient size, allosensitization, and blood type, biologic features that influence donor pool for a given recipient, do not impact allocation priority. Additionally, social determinants such as geography, socioeconomic status, race, and ethnicity can impact the likelihood of receiving a transplant. This has resulted in certain groups being transplanted at lower rates and at higher risk of dying on the waitlist. In order to address these disparities, lung organ allocation in the United States transitioned to a continuous distribution system using the composite allocation score (CAS) on 9 March 2023.

SUMMARY

In this article, we will review some of the data demonstrating the impact that biologic and social determinants have had on lung allocation in order to provide background as to why these have been incorporated into the CAS.

Lung transplant waitlist outcomes among ABO blood groups vary based on disease severity

BACKGROUND

Blood group O candidates have lower lung transplantation rates despite having the most common blood group. We postulated that waitlist outcomes among these candidates and those with other blood types vary with disease severity and lung allocation score (LAS).

METHODS

We performed a retrospective cohort study of 32,772 waitlist candidates using the United Network of Organ Sharing registry from May 2005 to 2020. After identifying an interaction between blood group and LAS, we evaluated the association between blood group and waitlist outcomes within LAS quartiles using unadjusted and adjusted competing risk models.

RESULTS

In the lowest LAS quartile, blood group O had a 20% reduced transplantation rate (SHR: 0.80, 95%CI: 0.75-0.85) and higher waitlist death/removal (1.33, 95%CI: 1.15-1.55) compared with group A. Blood group AB had a 52% higher transplantation rate (SHR: 1.52, 95%CI: 1.34-1.73) in the lowest LAS quartile compared with group A. In the highest LAS quartile, there was no difference in transplantation rates between groups O and A. In contrast, group B had a 19% reduced transplantation rate (SHR, 0.81 95%CI: 0.73-0.89) and AB had a 28% reduced transplantation rate (SHR: 0.72, 95%CI: 0.61-0.86) in the highest LAS quartile. Additionally, groups B and AB had increased risk of waitlist death/removal in the highest LAS quartile compared with A (SHR: 1.27, 95%CI: 1.08-1.48; SHR: 1.31, 95%CI: 1.00-1.72).

CONCLUSIONS

Waitlist outcomes among ABO blood groups vary depending on illness severity, which is represented by LAS. Blood group O has lower transplantation rates at low LAS while groups B and AB have lower transplantation rates at high LAS.

Addressing sex-based disparities in solid organ transplantation in the United States - a conference report

Solid organ transplantation provides the best treatment for end-stage organ failure, but significant sex-based disparities in transplant access exist. On June 25, 2021, a virtual multidisciplinary conference was convened to address sex-based disparities in transplantation. Common themes contributing to sex-based disparities were noted across kidney, liver, heart, and lung transplantation, specifically the existence of barriers to referral and wait listing for women, the pitfalls of using serum creatinine, the issue of donor/recipient size mismatch, approaches to frailty and a higher prevalence of allosensitization among women. In addition, actionable solutions to improve access to transplantation were identified, including alterations to the current allocation system, surgical interventions on donor organs, and the incorporation of objective frailty metrics into the evaluation process. Key knowledge gaps and high-priority areas for future investigation were also discussed.

Lung Transplantation Waitlist Mortality Among Sarcoidosis Patients by Lung Allocation Score Grouping

BACKGROUND

The Lung Allocation Score (LAS) system was designed to equalize and minimize waitlist mortality among candidiates for lung transplantation. The LAS stratifies sarcoidosis patients by mean pulmonary arterial pressure (mPAP) into group A (mPAP ≤30 mm Hg) and group D (mPAP >30 mm Hg). In this study, we aimed to analyze the effect of diagnostic grouping and patient characteristics on waitlist mortality among sarcoidosis patients.

METHODS

This was a retrospective review of sarcoidosis lung transplantation candidates since LAS implementation in May 2005 through May 2019 in the Scientific Registry of Transplant Recipients database. We compared baseline characteristics, LAS variables, and waitlist outcomes between sarcoidosis groups A and D. We performed Kaplan-Meier survival analysis and multivariable regression to determine associations with waitlist mortality.

RESULTS

We identified 1027 sarcoidosis candidates since LAS implementation. Of these, 385 had mPAP ≤30 mm Hg and 642 had mPAP >30 mm Hg. Waitlist mortality was 18% in sarcoidosis group D and 14% in sarcoidosis group A. Kaplan-Meier curve showed lower waitlist survival probability for sarcoidosis group D than group A (log-rank P = .0049). Functional status, oxygen requirement, and sarcoidosis group D were associated with increased waitlist mortality. Cardiac output ≥4 L/min was associated with decreased waitlist mortality.

CONCLUSION

Sarcoidosis group D had lower waitlist survival than group A. Decreased survival appears driven by mPAP; sarcoidosis group D, functional status, oxygen requirement, and cardiac output had significant associations with waitlist mortality. These findings suggest that the current LAS grouping does not adequately reflect the risk for waitlist mortality among sarcoidosis group D patients.

Predictors of lung transplant waitlist mortality for sarcoidosis

RATIONALE

Unlike in other chronic lung diseases, criteria for lung transplant referral in sarcoidosis is not well-established. Waitlist mortality may offer clues in identifying clinical factors that warrant early referral. We aim to identify predictors for transplant waitlist mortality to improve referral criteria for patients with sarcoidosis.

METHODS

We conducted a retrospective analysis of 1034 sarcoidosis patients listed for lung transplantation from May 2005 to May 2019 in the Scientific Registry of Transplant Recipients (SRTR) database. All patients were listed after the establishment of the Lung Allocation Score (LAS). We compared patients who died on the transplant waitlist to those who survived to transplantation. Potential predictors of waitlist mortality were assessed utilizing univariate and multivariate analysis performed via logistic regression modeling.

RESULTS

Of 1034 candidates listed after LAS implementation, 704 were transplanted and 110 died on the waitlist. Significant predictors of waitlist mortality on multivariate analysis include female gender (OR 2.445; 95% CI 1.513-3.951; p = 0.0003) and severe pulmonary hypertension (OR 1.619; 95% CI 1.067-2.457; p = 0.0236). Taller minimum donor height (OR 0.606; 95% CI 0.379-0.969; p = 0.0365) and blood type B (OR 0.524; 95% CI 0.281-0.975 p = 0.0415) were associated with decreased likelihood of death on the waitlist.

CONCLUSION

Among patients with sarcoidosis on the lung transplant waitlist, taller minimum donor height and blood type B were found to be protective factors against death on the waitlist. Female gender and severe pulmonary hypertension have a higher likelihood of death and earlier referral for transplantation in patients with these characteristics should be considered.

Analysis of sex-based differences in clinical and molecular responses to ischemia reperfusion after lung transplantation

Background

Sex and hormones influence immune responses to ischemia reperfusion (IR) and could, therefore, cause sex-related differences in lung transplantation (LTx) outcomes. We compared men’s and women’s clinical and molecular responses to post-LTx IR.

Methods

In 203 LTx patients, we used the 2016 International Society for Heart and Lung Transplantation guidelines to score primary graft dysfunction (PGD). In a subgroup of 40 patients with blood samples collected before LTx (T0) and 6, 24, 48 (T48), and 72 h (T72) after lung reperfusion, molecular response to IR was examined through serial analysis of circulating cytokine expression.

Results

After adjustment, women had less grade 3 PGD than men at T48, but not at T72. PGD grade decreased from T0 to T72 more often in women than men. The evolution of PGD (the difference in mean PGD between T72 and T0) was greater in men. However, the evolution of IL-2, IL-7, IL-17a, and basic fibroblast growth factor levels was more often sustained throughout the 72 h in women. In the full cohort, we noted no sex differences in secondary clinical outcomes, but women had significantly lower peak lactate levels than men across the 72 h.

Conclusions

Men and women differ in the evolution of PGD and cytokine secretion after LTx: Women have a more sustained proinflammatory response than men despite a greater reduction in PGD over time. This interaction between cytokine and PGD responses warrants investigation. Additionally, there may be important sex-related differences that could be used to tailor treatment during or after transplantation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01900-y.

Disparities in heart and lung transplantation

PURPOSE OF REVIEW

Cardiothoracic transplantation is the definitive therapy for end-stage heart and lung disease. In service to this population, disparities in access and care must be simultaneously understood and addressed.

RECENT FINDINGS

There are sex, race, geographic, age, and underlying disease disparities in both heart and lung transplantation. Women have reduced waitlist survival but improved posttransplant survival when compared with men for both heart and lung transplantation. Black patients have worse outcome compared with other races postheart transplant. Geographic disparities impact the likelihood of receiving heart or lung transplant and the growing number of patients with advanced age seeking transplant complicates discussions on survival benefit. Finally, underlying disease has affected outcomes for both heart and lung transplant and now are incorporated into the allocation system.

SUMMARY

Though heart and lung transplantation have several existing disparities, it remains to be seen how advancements in medical technology, changes in donor organ allocation policies, and growing experience in patient selection will impact these concerns.

Lung transplantation for interstitial lung disease

Lung transplantation (LTx) can be a life-extending treatment option for patients with advanced and/or progressive fibrotic interstitial lung disease (ILD), especially idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis, sarcoidosis and connective tissue disease-associated ILD. IPF is now the most common indication for LTx worldwide. Several unique features in patients with ILD can impact optimal timing of referral or listing for LTx, pre- or post-transplant risks, candidacy and post-transplant management. As the epidemiology of LTx and community practices have evolved, recent literature describes outcomes and approaches in higher-risk candidates. In this review, we discuss the unique and important clinical findings, course, monitoring and management of patients with IPF and other progressive fibrotic ILDs during pre-LTx evaluation and up to the day of transplantation; the need for co-management with clinical experts in ILD and LTx is emphasised. Some post-LTx complications are unique in these patient cohorts, which require prompt detection and appropriate management by experts in multiple disciplines familiar with telomere biology disorders and infectious, haematological, oncological and cardiac complications to enhance the likelihood of improved outcomes and survival of LTx recipients with IPF and other ILDs.

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.

Association between Allosensitization and Waiting List Outcomes among Adult Lung Transplant Candidates in the United States

Rationale: Allosensitization may be a barrier to lung transplant. Currently, consideration is not given to allosensitization when assigning priority on the lung transplant waiting list. Objectives: We aimed to examine the association between allosensitization and waiting list outcomes. Methods: We conducted a retrospective single-center cohort study of adults listed for lung transplant at our center between January 1, 2006, and December 31, 2016. We screened candidates for human leukocyte antigen antibodies before listing and examined the association between allosensitization and waiting list outcomes, including likelihood of transplant and death on the waiting list, using a competing risk model. Calculated panel-reactive antibody (CPRA) was used as a continuous measure of allosensitization. Results: Among 746 candidates who were listed for lung transplant during the study period, 263 (35%) were allosensitized, and 483 (65%) were not. In unadjusted analysis, allosensitized candidates had a decreased likelihood of transplant compared with nonallosensitized candidates (subhazard ratio [sHR], 0.71; 95% confidence interval [CI], 0.60-0.83; P < 0.001) and were more likely to die on the waiting list (sHR, 1.66; 95% CI, 1.08-2.58; P < 0.001). In multivariable modeling, increasing CPRA was associated with an increased risk of death and a decreased likelihood of transplant (sHR for death, 1.15 per 10% increase in CPRA; 95% CI, 1.07-1.22; P < 0.001; sHR for transplant, 0.89 per 10% increase in CPRA; 95% CI, 0.86-0.91; P < 0.001). Conclusions: Broad allosensitization was associated with longer waiting times, decreased likelihood of transplant, and increased risk of death among candidates on the waiting list for lung transplant. Consideration of allosensitization in organ allocation strategies might help mitigate this increased risk in highly allosensitized candidates.

Variability in donor organ offer acceptance and lung transplantation survival

BACKGROUND

Lung transplantation offers a survival benefit for patients with end-stage lung disease. When suitable donors are identified, centers must accept or decline the offer for a matched candidate on their waitlist. The degree to which variability in per-center offer acceptance practices impacts candidate survival is not established. The purpose of this study was to determine the degree of variability in per-center rates of lung transplantation offer acceptance and to ascertain the associated contribution to observed differences in per-center waitlist mortality.

METHODS

We performed a retrospective cohort study of candidates waitlisted for lung transplantation in the US using registry data. Logistic regression was fit to assess the relationship of offer acceptance with donor, candidate, and geographic factors. Listing center was evaluated as a fixed effect to determine the adjusted per-center acceptance rate. Competing risks analysis employing the Fine-Gray model was undertaken to establish the relationship between adjusted per-center acceptance and waitlist mortality.

RESULTS

Of 15,847 unique organ offers, 4,735 (29.9%) were accepted for first-ranked candidates. After adjustment for important covariates, transplant centers varied markedly in acceptance rate (9%-67%). Higher cumulative incidence of 1-year waitlist mortality was associated with lower acceptance rate. For every 10% increase in adjusted center acceptance rate, the risk of waitlist mortality decreased by 36.3% (sub-distribution hazard ratio 0.637; 95% confidence interval 0.592-0.685).

CONCLUSIONS

Variability in center-level behavior represents a modifiable risk factor for waitlist mortality in lung transplantation. Further intervention is needed to standardize center-level offer acceptance practices and minimize waitlist mortality.

Ethical Considerations for Mechanical Support

Extracorporeal life support can support patients with severe forms of cardiac and respiratory failure. Uncertainty remains about its optimal use owing in large part to its resource-intensive nature and the high acuity illness in supported patients. Specific issues include the identification of patients most likely to benefit, the appropriate duration of support when prognosis is uncertain, and what to do when patients become dependent on extracorporeal life support but no longer have hope for recovery or transplantation. Careful deliberation of ethical principles and potential dilemmas should be made when considering the use of extracorporeal life support in advanced cardiopulmonary failure.

Lung transplant referral for individuals with cystic fibrosis: Cystic Fibrosis Foundation consensus guidelines

OBJECTIVE

Provide recommendations to the cystic fibrosis (CF) community to facilitate timely referral for lung transplantation for individuals with CF.

METHODS

The CF Foundation organized a multidisciplinary committee to develop CF Lung Transplant Referral Consensus Guidelines. Three workgroups were formed: timing for transplant referral; modifiable barriers to transplant; and transition to transplant care. A focus group of lung transplant recipients with CF and spouses of CF recipients informed guideline development.

RESULTS

The committee formulated 21 recommendation statements based on literature review, committee member practices, focus group insights, and in response to public comment. Critical approaches to optimizing access to lung transplant include early discussion of this treatment option, assessment for modifiable barriers to transplant, and open communication between the CF and lung transplant centers.

CONCLUSIONS

These guidelines will help CF providers counsel their patients and may reduce the number of individuals with CF who die without consideration for lung transplant.

Lung transplant: the Western Australian experience

BACKGROUND

The Western Australian lung transplant programme commenced in 2004 to serve the growing demand of patients with end-stage lung disease.

AIM

This report summarises our 11-year experience in lung transplantation.

METHODS

Data on 115 consecutive patients and their respective donors transplanted between 2004 and 2015 were collected. The Kaplan-Meier method was used to estimate survival. Cox regression was used to analyse the impact of donor and recipient characteristics on survival.

RESULTS

A total of 88 bilateral, 22 single-lung and 5 heart-lung transplants were performed in Western Australia during the first 11 years of the lung transplant programme. The most common indications for transplantation were interstitial lung disease (30.4%), cystic fibrosis (27.8%) and chronic obstructive pulmonary disease (excluding alpha-1 antitrypsin deficiency) (22.6%). Median recipient age was 50 years. Overall survival rates were 96% at 3 months, 93% at 1 year, 84% at 3 years and 70% at 5 years. Older age and higher BMI negatively impacted survival. Chronic lung allograft dysfunction was the leading cause of late mortality.

CONCLUSION

Lung transplantation is a treatment option in end-stage lung disease, with annual transplant rates in Western Australia continuing to rise. Our patients enjoy survival rates that compare favourably against international standards.

Multiple listing in lung transplant candidates: A cohort study

Lung transplant candidates can be waitlisted at more than one transplant center, a practice known as multiple listing. The factors associated with multiple listing and whether multiple listing modifies waitlist mortality or likelihood of lung transplant is unknown. US lung transplant waitlist candidates were identified as either single or multiple listed using data from the Scientific Registry of Transplant Recipients. Characteristics of single and multiple listed candidates were compared and multivariable logistic regression was used to estimate associations with multiple listing. Multiple listed candidates were matched to single listed candidates using a combination of exact and propensity score matching methods. Cox proportional hazard models were used to estimate the relationship of multiple listing on waitlist mortality and receiving a transplant. Multiple listing occurred in 2.3% of lung transplant waitlist candidates. Younger age, female gender, white race, short stature, high antibody sensitization, college or postcollege education, lower lung allocation score, and a cystic fibrosis diagnosis were independently associated with multiple listing. Multiple listing was associated with an increased likelihood of lung transplant (adjusted hazard ratio [aHR] 2.74, 95% CI 2.37 to 3.16) but was not associated with waitlist mortality (aHR 0.99, 95% CI 0.68 to 1.44).

The Future of Lung Transplantation

The field of lung transplant has made significant advances over the last several decades. Despite these advances, morbidity and mortality remain high when compared with other solid organ transplants. As the field moves forward, the speed by which progress can be made will in part be determined by our ability to overcome several stumbling blocks, including donor shortage, proper selection of candidates, primary graft dysfunction, and chronic lung allograft dysfunction. The advances and developments surrounding these factors will have a significant impact on shaping the field within the coming years. In this review, we look at the current climate (ripe for expanding the donor pool), new technology (ex vivo lung perfusion and bioengineered lungs), cutting-edge innovation (novel biomarkers and new ways to treat infected donors), and evidence-based medicine to discuss current trends and predict future developments for what we hope is a bright future for the field of lung transplantation.

Geographic disparities in donor lung supply and lung transplant waitlist outcomes: A cohort study

Despite the Final Rule mandate for equitable organ allocation in the United States, geographic disparities exist in donor lung allocation, with the majority of donor lungs being allocated locally to lower-priority candidates. We conducted a retrospective cohort study of 19 622 lung transplant candidates waitlisted between 2006 and 2015. We used multivariable adjusted competing risk survival models to examine the relationship between local lung availability and waitlist outcomes. The primary outcome was a composite of death and removal from the waitlist for clinical deterioration. Waitlist candidates in the lowest quartile of local lung availability had an 84% increased risk of death or removal compared with candidates in the highest (subdistribution hazard ratio [SHR]: 1.84, 95% confidence interval [CI]: 1.51-2.24, P < .001). The transplantation rate was 57% lower in the lowest quartile compared with the highest (SHR: 0.43, 95% CI: 0.39-0.47). The adjusted death or removal rate decreased by 11% with a 50% increase in local lung availability (SHR: 0.89, 95% CI: 0.85-0.93, P < .001) and the adjusted transplantation rate increased by 19% (SHR: 1.19, 95% CI: 1.17-1.22, P < .001). There are geographically disparate waitlist outcomes in the current lung allocation system. Candidates listed in areas of low local lung availability have worse waitlist outcomes.

Pediatric lung transplantation and end of life care in cystic fibrosis: Barriers and successful strategies

Pediatric lung transplantation has advanced over the years, providing a potential life-prolonging therapy to patients with cystic fibrosis. Despite this, many challenges in lung transplantation remain and result in worse outcomes than other solid organ transplants. As CF lung disease progresses, children and their caregivers are often simultaneously preparing for lung transplantation and end of life. In this article, we will discuss the current barriers to success in pediatric CF lung transplantation as well as approaches to end of life care in this population.

Extracorporeal Life Support in Lung Transplantation

Extracorporeal life support in lung transplantation has been associated with poor posttransplant outcomes. However, recent advances have resulted in more favorable posttransplant outcomes. The increased use of this technology must be weighed against the risks inherent in its use, especially when complications arising in extracorporeal membrane oxygenation (ECMO)-dependent patients result in loss of transplant candidacy, leaving them with no viable alternative for long-term support. Existing and emerging data support the judicious use of this technology in carefully selected patients at high-volume transplant and ECMO centers that prioritize minimization of sedation, avoidance of endotracheal intubation, and early mobilization.

Contemporary Issues in Lung Transplant Allocation Practices

PURPOSE OF REVIEW

To discuss the current state of donor lung allocation in the United States, and future opportunities to increase the efficiency of donor lung allocation.

RECENT FINDINGS

The current donor lung allocation system prioritizes clinical acuity by use of the Lung Allocation Score (LAS) which has reduced waitlist mortality since its implementation in 2005. Access to donor lungs can be further improved through policy changes using broader geographic sharing, and developing new technology such as ex vivo lung perfusion to recover marginal donor lungs.

SUMMARY

The number of lung transplants in the U.S. continues to increase annually. However, the demand for donor lungs continues to be outpaced by an ever growing waitlist. Efficient allocation can be achieved through improved allocation policies and new technology.

Awake Extracorporeal Membrane Oxygenation as Bridge to Lung Transplantation: A 9-Year Experience

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is used as a bridge to lung transplantation, but characteristics that influence its success are poorly understood. This large, single-center experience evaluated the implementation and outcomes of ECMO in this setting.

METHODS

Data were collected for patients at our institution (New York-Presbyterian Hospital/Columbia University Medical Center in New York) who received ECMO as a bridge to lung transplantation from January 1, 2007 through July 10, 2016. Data were analyzed for demographics, baseline characteristics, survival, and ECMO configuration.

RESULTS

Seventy-two patients received ECMO as a bridge to lung transplantation. Of the 72 patients, 40 (55.6%) underwent the transplantation procedure, 37 (92.5%) survived to discharge, and 21 (84.0%) survived for 2 years. Inotropy or vasopressor support (70% vs 93.8%; p = 0.011), Simplified Acute Physiology Score (26.8 vs 30.5; p = 0.048), and ambulation (80% vs 56.2%; p = 0.030) were significantly different between the patients who underwent lung transplantation and those who did not. Patients with cystic fibrosis were more likely to have a bridge to transplantation than patients with other lung diseases (47.5% vs 25%; p = 0.050). Daily participation in physical therapy was achieved in 50 patients (69.4%).

CONCLUSIONS

This study demonstrated favorable survival in patients receiving ECMO as a bridge to lung transplantation and achieved high rates of physical therapy and avoidance of mechanical ventilation while ECMO was used in patients awaiting lung transplantation. With more than half of these patients successfully bridged to lung transplantation, we gained insight into the factors influencing patients' outcomes, including patient selection, timing of ECMO, and patient management.

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.

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.