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.

RACIAL AND ETHNIC DIFFERENCES IN LUNG CANCER SCREENING ELIGIBILITY AND HEALTH CARE UTILIZATION AMONG OLDER SMOKERS

The United States Preventive Task Force (USPSTF) expanded the lung cancer screening guidelines with low-dose CT scan (LDCT) to narrow racial and ethnic screening disparities. However, there is a need to examine if eligible individuals can access and use health care. The objective was to examine racial and ethnic differences in LDCT eligibility and health services access and utilization among LDCT-eligible individuals. Data comes from adults 50 to 80 years old in the 2018 Health and Retirement Study (HRS), with at least a 20 pack-year smoking history who currently smoke, or have quit < 15 years ago (n=7,624). The outcomes were LDCT eligibility, access to health care (health insurance and usual place of care), and health care use (visits to the doctor). White individuals were more likely to be LDCT eligible than Black and Hispanic individuals. Among those LDCT eligible, Hispanic individuals were less likely to have insurance (OR:0.43, [95%CI: 0.21; 0.86]) and to visit the doctor than White individuals (OR: 0.38 [0.19; 0.76]). Compared to White individuals, Black individuals were more likely to say their usual place of care was the ER or “other” place (OR: 2.65 [1.63; 3.32] and Hispanic individuals were more likely to say they do not have a usual place of care (OR: 1.94 [1.10; 3.41]). Expanding the criteria for lung cancer screening may not be enough to reduce racial and ethnic disparities. More efforts should address racial and ethnic disparities in the implementation of lung cancer screening, including access and use of health care.

Age at Diagnosis for Lung, Colon, Breast, and Prostate Cancers: An International Comparative Study

PURPOSE

Differences in the age at diagnosis for lung, colon, breast, and prostate cancers have been reported between low- and middle-income countries (LMICs) and high-income countries (HICs). However, this may be influenced by differences in the population age distributions across countries. We aimed to compare the median age at diagnosis for these cancers after adjusting for population age differences.

METHODS

We analyzed data from the Cancer Incidence in 5 Continents (CI5) Volume XI database. It includes information on cancer diagnoses during 2008 to 2012 from cancer registries in 66 countries. We calculated crude median ages at diagnosis for each cancer in each country, and then performed indirect standardization using the age-specific UN world population estimate to remove the influence of population age structure.

RESULTS

Overall, the adjustment for population age structure tended to increase the median ages at diagnosis in LMICs which have younger populations, and decrease them in HICs which have older populations. After standardization, differences between the youngest and oldest median ages of diagnosis across cancer sites were: 11 years for lung cancer (youngest median age observed was 61 in Bulgaria v 71 in Bahrain), 10 years for colon cancer (59 in Iran v 69 New Zealand), 10 years for breast (49 in Algeria v 59 Iceland), and 8 years for prostate cancer (65 in USA v 73 in the Philippines). LMICs had younger ages at diagnosis for colon cancer but older ages at diagnosis for prostate cancer as compared with HICs. Countries with higher smoking prevalence had younger ages at lung cancer diagnosis ( P value Pearson correlation = 0.0025).

CONCLUSION

For lung, colon, breast, and prostate cancers, the differences across countries in the median age at diagnosis range from 8 to 11 years after adjusting for population age distribution. These differences likely reflect population-level variation in risk factors and screening.

A state-of-the-art review of stratified medicine in cancer: towards a future precision medicine strategy in cancer

BACKGROUND

Building on the success of targeted therapy in certain well-defined cancer genotypes, three platform studies-NCI-MATCH, LUNG-MAP and The National Lung Matrix Trial (NLMT)-have attempted to discover new genotype-matched therapies for people with cancer.

PATIENTS AND METHODS

We review the outputs from these platform studies. This review led us to propose a series of recommendations and considerations that we hope will inform future precision medicine programmes in cancer.

RESULTS

The three studies collectively screened over 13 000 patients. Across 37 genotype-matched cohorts, there have been 66/875 responders, with an overall response rate of 7.5%. Targeting copy number gain yielded 5/199 responses across nine biomarker-drug matched cohorts, with a response rate of 2.5%.

CONCLUSIONS

The majority of these studies used single-agent targeted therapies. Whilst preclinical data can suggest rational combination treatment to reverse adaptive resistance or block parallel activated pathways, there is an essential need for accurate modelling of the toxicity-activity trade-off of combinations. Agent selection is often suboptimal; dose expansion should only be carried out with agents with clear clinical proof of mechanism and high target selectivity. Targeting copy number change has been disappointing; it is crucial to define the drivers on shared amplicons that include the targeted aberration. Maximising outcomes with currently available targeted therapies requires moving towards a more contextualised stratified medicine acknowledging the criticality of the genomic, transcriptional and immunological context on which the targeted aberration is inscribed. Genomic complexity and instability is likely to be a leading cause of targeted therapy failure in genomically complex cancers. Preclinical models must be developed that more accurately capture the genomic complexity of human disease. The degree of attrition of studies carried out after standard-of-care therapy suggests that serious efforts be made to develop a suite of precision medicine studies in the minimal residual disease setting.

Malakoplakia Presenting as a Lung Mass in a Lung Transplant Recipient: Case Report

Lung nodules or masses due to a variety of malignant or benign conditions such as opportunistic infections are observed after lung transplant. Malakoplakia is a rare complication in immunocompromised patients. Here we describe the clinical course and management of a lung transplant recipient with pulmonary malakoplakia and provide a review of the literature. To our knowledge, this is the first report of a case of pulmonary malakoplakia due to Escherichia coli infection in a lung allograft.

Geographic disparities in lung transplantation in the United States before and after the November 2017 allocation change

BACKGROUND

The primary lung allocation unit was expanded from the donation service area to a 250-mile radius in 2017. Prior to the change, geographic disparities in donor lung availability impacted waitlist outcomes. We sought to determine if the new allocation system improved these disparities.

METHODS

We conducted a retrospective cohort study comparing the 2-year period before and after the change. Donor lung availability was defined as the ratio of donor lungs to waitlist candidates in the primary allocation unit. Transplant centers were divided into quartiles by donor lung availability. Multivariable competing risk models were used to determine the association between lung availability and waitlist outcomes. Multivariable Cox proportional hazards models compared post-transplant survival.

RESULTS

Prior to the allocation change, the unadjusted transplant rate at centers in the lowest and highest quartiles was 132 and 607 transplants per 100 waitlist years. Candidates in the lowest quartile of donor lung availability had a 61% adjusted lower transplantation rate compared to candidates in highest quartile (sub-hazard ratio [sHR]: 0.39, 95% confidence interval [CI]: 0.34-0.44). After the allocation change, the disparity decreased resulting in an unadjusted transplant rate of 141 and 309 among centers in the lowest and highest quartiles. Candidates in the lowest quartile had a 38% adjusted lower transplantation rate compared to those in the highest (sHR: 0.62, 95% CI: 0.57-0.68). There was no significant difference in 1-year post-transplant survival.

CONCLUSIONS

Although the expansion of the primary allocation unit improved disparities in waitlist outcomes without any change in post-transplant survival, there still remain significant differences due to geography.

Fundoplication after lung transplantation in patients with systemic sclerosis-related end-stage lung disease

INTRODUCTION

Gastroesophageal reflux and aspiration are risk factors for chronic lung allograft dysfunction in lung transplant recipients. Patients with systemic sclerosis are at an increased risk of aspiration due to esophageal dysmotility and an ineffective lower esophageal sphincter. The aim of this study is to understand the effect of fundoplication on outcomes in systemic sclerosis recipients.

METHODS

Between 2001 and 2019, 168 systemic sclerosis patients were referred for lung transplantation-51 (30.3%) were listed and 36 (21.4%) were transplanted. Recipients were stratified whether they underwent a fundoplication (n = 10, 27.8%) or not (n = 26, 72.2%). Freedom from chronic lung allograft dysfunction and survival were analyzed using log-rank test. Multivariable analysis for known risk factors was performed using a Cox-proportional hazards model.

RESULTS

Median time to fundoplication after transplantation was 16.4 months (interquartile range: 9.6-25.1) and all were laparoscopic (Dor 50%, Nissen 40%, Toupet 10%). There were no differences in acute rejection ⩾ A1 (26.9% vs 30%), or primary graft dysfunction grades 2-3 at 72 h (42.3% vs 40%) between groups. Recipients with fundoplication had an increased freedom from chronic lung allograft dysfunction (p = 0.035) and overall survival (p = 0.01). Fundoplication was associated with a reduced risk of mortality adjusting for other comorbidities (hazard ratio = 0.13; 95% confidence interval = 0.02-0.65; p = 0.014). Double and single lung transplant did not have different post-transplant survival.

CONCLUSION

Fundoplication in systemic sclerosis lung transplant recipients is associated with greater freedom from chronic lung allograft dysfunction and overall survival. Screening for reflux and aspiration followed by early fundoplication may delay graft deterioration in this population.

Lung transplantation disparities based on diagnosis for patients bridging to transplant on extracorporeal membrane oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is increasingly utilized as a bridge to lung transplantation, but ECMO status is not explicitly accounted for in the Lung Allocation Score (LAS). We hypothesized that among waitlist patients on ECMO, patients with pulmonary arterial hypertension (PAH) would have lower transplantation rates.

METHODS

Using United Network for Organ Sharing data, we conducted a retrospective cohort study of patients who were ≥12 years old, active on the lung transplant waitlist, and required ECMO support from June 1, 2015 through June 12, 2020. Multivariable competing risk analysis was used to examine waitlist outcomes.

RESULTS

1064 waitlist subjects required ECMO support; 40 (3.8%) had obstructive lung disease (OLD), 97 (9.1%) had PAH,138 (13.0%) had cystic fibrosis (CF), and 789 (74.1%) had interstitial lung disease (ILD). Ultimately, 671 (63.1%) underwent transplant, while 334 (31.4%) died or were delisted. The transplant rate per person-years on the waitlist on ECMO was 15.41 for OLD, 6.05 for PAH, 15.66 for CF, and 15.62 for ILD. Compared to PAH patients, OLD, CF, and ILD patients were 78%, 69%, and 62% more likely to undergo transplant throughout the study period, respectively (adjusted SHRs 1.78 p = 0.007, 1.69 p = 0.002, and 1.62 p = 0.001). The median LAS at waitlist removal for transplantation, death, or delisting were 75.1 for OLD, 79.6 for PAH, 91.0 for CF, and 88.3 for ILD (p < 0.001).

CONCLUSIONS

Among patients bridging to transplant on ECMO, patients with PAH had a lower transplantation rate than patients with OLD, CF, and ILD.

Identification of Lung Transplant Recipients with a Survival Benefit after Fundoplication

BACKGROUND

Gastroesophageal reflux disease (GERD) and aspiration of enteric contents is associated with worse outcomes after lung transplant. The purpose of this study is to elucidate populations that benefit the most from fundoplication after lung transplant.

METHODS

Lung transplants from 2001-2019 (n=971) were retrospectively reviewed and stratified by a fundoplication before (n=128) or after (n=24) chronic lung allograft dysfunction (CLAD) development vs those who didn't. Patients with a fundoplication prior to CLAD were propensity-matched to those without a fundoplication. The primary outcome of interest was post-transplant survival. Time-to-event rates were calculated using a multivariable Cox proportional hazards model and Kaplan-Meier functions.

RESULTS

A fundoplication prior to CLAD improved post-transplant survival before and after propensity-matching, and remained a significant predictor after adjusting for baseline characteristics (HR:0.57, 95% CI:0.4-0.8, P=0.001). Recipients with a restrictive disorder (HR: 0.46, 95% CI:0.3-0.73, P=0.001), age <65 (HR:0.48, 95% CI:0.32-0.71, P<0.001), and both single (HR:0.47, 95% CI:0.28-0.79, P=0.005) or double (HR:0.55, 95% CI:0.32-0.93, P=0.027) lung transplants had a significant decrease in mortality after fundoplication. The effect was present after excluding early deaths and/or CLAD diagnoses. GERD diagnosed by pH, impedance or EGD was not associated with worse outcomes. Among patients with CLAD, a fundoplication was an independent predictor of post-CLAD survival (HR:0.27, 95% CI:0.12-0.61, P=0.002).

CONCLUSIONS

A fundoplication before or after CLAD development is an independent predictor of survival. Younger patients with restrictive disease, independent of the type of transplant, have a survival benefit. GERD diagnosed by conventional methods was not associated with worse survival.

Less bleeding associated with apixaban versus other direct acting oral anticoagulation in solid organ transplant recipients

BACKGROUND

The purpose of this study was to evaluate outcomes of bleeding and thrombosis resulting from the use of DOACs in a large cohort of SOT recipients.

METHODS

This was a single center, retrospective cohort study of adult kidney, heart, lung, and liver transplant recipients transplanted between August 2009 and May 2018. Patients were stratified into two groups: those who received apixaban (apixaban group) or those patients receiving either rivaroxaban or dabigatran (non-apixaban group). The primary endpoint was the cumulative incidence of bleeding while receiving DOAC therapy. The secondary endpoints were incidence of major bleeding and thrombosis at any time while receiving DOAC therapy.

RESULTS

A total of 106 patients were included; 70 patients received apixaban and 36 patients received non-apixaban anticoagulation. Cumulative incidence of any bleeding was lower in the apixaban group compared to the non-apixaban group at both 90 days (4.9% versus 16.1%) and 180 days (11.4% versus 24.9%, P = 0.034). Cumulative incidence of major bleeding (P = 0.686) and thrombosis (P = 0.515) were similar between groups. DOAC dosing congruent with the package insert(s) was associated with a lower risk of thrombosis.

CONCLUSION

Apixaban-based anticoagulation was associated with a lower cumulative incidence of any bleeding compared to non-apixaban DOACs. This article is protected by copyright. All rights reserved.

Geographic Differences in Lung Transplant Volume and Donor Availability During the COVID-19 Pandemic

BACKGROUND

Regional variation in lung transplantation practices due to local coronavirus disease 2019 (COVID-19) prevalence may cause geographic disparities in access to lung transplantation.

METHODS

Using the United Network for Organ Sharing registry, we conducted a descriptive analysis of lung transplant volume, donor lung volume, new waitlist activations, and waiting list deaths at high-volume lung transplant centers during the first 3 months of the pandemic (March 1. 2020, to May 30, 2020) and we compared it to the same period in the preceding 5 years.

RESULTS

Lung transplant volume decreased by 10% nationally and by a median of 50% in high COVID-19 prevalence centers (range -87% to 80%) compared with a median increase of 10% (range -87% to 80%) in low prevalence centers (P-for-trend 0.006). Donation services areas with high COVID-19 prevalence experienced a greater decrease in organ availability (-28% range, -72% to -11%) compared with low prevalence areas (+7%, range -20% to + 55%, P-for-trend 0.001). Waiting list activations decreased at 18 of 22 centers. Waiting list deaths were similar to the preceding 5 years and independent of local COVID-19 prevalence (P-for-trend 0.36).

CONCLUSIONS

Regional variation in transplantation and donor availability in the early months of the pandemic varied by local COVID-19 activity.

COVID-19 in lung transplant recipients: A single center case series from New York City

There are limited data describing COVID-19 in lung transplant recipients. We performed a single center, retrospective case series study of lung transplant patients followed by the Columbia Lung Transplant program who tested positive for SARS-CoV-2 between March 19 and May 19, 2020. Thirty-two lung transplant patients developed mild (16%), moderate (44%), or severe (41%) COVID-19. The median age of patients was 65 years, and the median time from lung transplant was 5.6 years. Symptoms included cough (66%), dyspnea (50%), fever (47%), and gastrointestinal upset (44%). Patients received hydroxychloroquine (84%), azithromycin (75%), augmented steroids (44%), tocilizumab (19%), and remdesivir (9%). Eleven patients (34%) died at a median time of 14 days from admission. Complications during admission included: acute kidney injury (63%), transaminitis (31%), shock (31%), acute respiratory distress syndrome (25%), neurological events (25%), arrhythmias (22%), and venous thromboembolism (9%). Compared to patients with moderate COVID-19, patients with severe COVID-19 had higher peak white blood cell counts (15.8 vs 7 × 10³ /uL, P = .019), C-reactive protein (198 vs. 107 mg/L, P = .010) and D-dimer (8.6 vs. 2.1 ug/mL, P = .004) levels, and lower nadir lymphocyte counts (0.09 vs. 0.4 × 10³ /uL, P = .006). COVID-19 is associated with severe illness and a high mortality rate in lung transplant recipients.

What Awaits on the Other Side: Post-Lung Transplant Morbidity and Mortality After Pre-Transplant Hospitalization

Background

Morbidity and mortality rates after lung transplantation remain high compared to other solid organ transplants. In the lung allocation score era, patients given the highest priority on the waitlist are those with the greatest severity of illness, who often require preoperative hospitalization.

Material/Methods

To determine the association of pre-transplant hospitalization with post-transplant outcomes, we retrospectively evaluated 448 lung transplant recipients at our center between January 2010 and July 2017 (114 hospitalized; 334 outpatient).

Results

Survival was similar between the groups (hazard ratio 0.93 [95% CI 0.61 to 1.42], p=0.738). However, hospitalized patients had longer hospital and intensive care unit length of stay compared to outpatients – 25 vs. 18 days, (p<0.001) and 9.5 vs. 6 days, (p<0.001), respectively. Hospitalized patients had higher rates of Grade 3 primary graft dysfunction – 29.8% vs. 9.6%, p<0.001 – and remained mechanically ventilated longer – 6 vs. 3 days, p<0.001. A greater percentage of hospitalized patients needed a tracheostomy and a re-operation within 30 days – 39.5% vs. 15.3% (p<0.001) and 22.8% vs. 12.0% (p=0.005) – respectively. After discharge, 28% of hospitalized patients required acute rehabilitation compared with 12% of outpatients (p=0.001).

Conclusions

While pre-transplant hospitalization is not associated with mortality, it is associated with significant morbidity after transplant.

Generation and persistence of human tissue-resident memory T cells in lung transplantation

Tissue-resident memory T cells (T_RM) maintain immunity in diverse sites as determined in mouse models, whereas their establishment and role in human tissues have been difficult to assess. Here, we investigated human lung T_RM generation, maintenance, and function in airway samples obtained longitudinally from human leukocyte antigen (HLA)-disparate lung transplant recipients, where donor and recipient T cells could be localized and tracked over time. Donor T cells persist specifically in the lungs (and not blood) of transplant recipients and express high levels of T_RM signature markers including CD69, CD103, and CD49a, whereas lung-infiltrating recipient T cells gradually acquire T_RM phenotypes over months in vivo. Single-cell transcriptome profiling of airway T cells reveals that donor T cells comprise two T_RM-like subsets with varying levels of expression of T_RM-associated genes, whereas recipient T cells comprised non-T_RM and similar T_RM-like subpopulations, suggesting de novo T_RM generation. Transplant recipients exhibiting higher frequencies of persisting donor T_RM experienced fewer adverse clinical events such as primary graft dysfunction and acute cellular rejection compared with recipients with low donor T_RM persistence, suggesting that monitoring T_RM dynamics could be clinically informative. Together, our results provide spatial and temporal insights into how human T_RM develop, function, persist, and affect tissue integrity within the complexities of lung transplantation.

Effect of Calculated Panel Reactive Antibody Value on Waitlist Outcomes for Lung Transplant Candidates

Background

We conducted a retrospective cohort study using United Network of Organ Sharing (UNOS) data to determine the effect of the calculated panel reactive antibody (cPRA) value on waitlist outcomes for lung transplant candidates.

Material/Methods

We divided lung transplant candidates into groups based on their cPRA value at the time of waitlist activation (0–25%, 25.1–50%, 50.1–75%, and 75.1–100%) and compared each group’s waitlist outcomes to the lowest quartile (“minimally sensitized”) group. The primary outcome was lung transplantation and the secondary outcome was waitlist mortality (a composite of death on the waitlist/delisting for clinical deterioration).

Results

Compared to the minimally sensitized group, candidates with a cPRA value of 25.1–50% did not have a significantly different likelihood of undergoing lung transplant or waitlist mortality, candidates with a cPRA value of 50.1–75% were 25% less likely to undergo lung transplant and 44% more likely to die on the waitlist, and candidates with a cPRA value of 75.1–100% were 52% less likely to undergo lung transplant and 92% more likely to die on the waitlist.

Conclusions

CPRA values of greater than 50% are associated with significantly lower rates of transplantation and higher waitlist mortality.

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

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

Use of Lung Allografts From Donation After Cardiac Death Donors: A Single-Center Experience

BACKGROUND

Lung transplantation remains the only treatment for end-stage lung disease. Availability of suitable lungs does not parallel this growing trend. Centers using donation after cardiac death (DCD) donor lungs report comparable outcomes with those from brain-dead donors. Donor assessment protocols and consistent surgical teams have been advocated when considering using the use of DCD donors. We present our experience using lungs from Maastricht category III DCD donors.

METHODS

Starting 2007 to July 2016, 73 DCD donors were assessed, 44 provided suitable lungs that resulted in 46 transplants. A 2012 to October 2016 comparative cohort of 379 brain-dead donors were assessed. Recipient and donor characteristics and primary graft dysfunction (PGD) and survival were monitored.

RESULTS

Seventy-three DCD (40% dry run rate) donors assessed yielded 46 transplants (23 double, 6 right, and 17 left). Comparative cohort of 379 brain-dead donors yielded 237 transplants (112 double, 43 right, and 82 left). One- and 3-year recipient survival was 91% and 78% for recipients of DCD lungs and 91% and 75% for recipients of lungs from brain-dead donors, respectively. PGD 2 and 3 in DCD recipients at 72 hours was 4 of 46 (9%) and 6 of 46 (13%), respectively. Comparatively, brain-dead donor recipient cohort at 72 hours with PGD 2 and 3 was 23 of 237 (10%) and 41 of 237 (17%), respectively.

CONCLUSIONS

Our experience reaffirms the use of lungs from DCD donors as a viable source with favorable outcomes. Recipients from DCD donors showed equivalent PGD rate at 72 hours and survival compared with recipients from brain-dead donors.

An extension of a lemma of Wald

We define a natural extension of the concept of expectation of a random variable y as follows: M(y) = a if there exists a constant − ∞ ≦ a ≦ ∞ such that if y1, y2, … is a sequence of independent identically distributed (i.i.d.) random variables with the common distribution of y then

Donor lung assessment using selective pulmonary vein gases

OBJECTIVES

Standard donor lung assessment relies on imaging, challenge gases and subjective interpretation of bronchoscopic findings, palpation and visual assessment. Central gases may not accurately represent true quality of the lungs. We report our experience using selective pulmonary vein gases to corroborate the subjective judgement.

METHODS

Starting, January 2012, donor lungs have been assessed by intraoperative bronchoscopy, palpation and visual judgement of lung collapse upon temporary disconnection from ventilator, central gases from the aorta and selective pulmonary vein gases. Partial pressure of oxygen (pO₂) <300 mmHg on FiO₂ of 1.0 was considered low. The results of the chest X-ray and last pO₂ in the intensive care unit were also collected. Post-transplant primary graft dysfunction and survival were monitored.

RESULTS

To date, 259 consecutive brain-dead donors have been assessed and 157 transplants performed. Last pO₂ in the intensive care unit was poorly correlated with intraoperative central pO₂ (Spearman's rank correlation r_s = 0.29). Right inferior pulmonary vein pO₂ was associated (Mann-Whitney, P < 0.001) with findings at bronchoscopy [clean: median pO₂ 443 mmHg (25th-75th percentile range 349-512) and purulent: 264 mmHg (178-408)]; palpation [good: 463 mmHg (401-517) and poor: 264 mmHg (158-434)] and visual assessment of lung collapse [good lung collapse: 429 mmHg (320-501) and poor lung collapse: 205 mmHg (118-348)]. Left inferior pulmonary pO₂ was associated (P < 0.001) with findings at bronchoscopy [clean: 419 mmHg (371-504) and purulent: 254 mmHg (206-367)]; palpation [good: 444 mmHg (400-517) and poor 282 mmHg (211-419)] and visual assessment of lung collapse [good: 420 mmHg (349-496) and poor: 246 mmHg (129-330)]. At 72 h, pulmonary graft dysfunction 2 was in 21/157 (13%) and pulmonary graft dysfunction 3 in 17/157 (11%). Ninety-day and 1-year mortalities were 6/157 (4%) and 13/157 (8%), respectively.

CONCLUSIONS

Selective pulmonary vein gases provide corroborative objective support to the findings at bronchoscopy, palpation and visual assessment. Central gases do not always reflect true function of the lungs, having high false-positive rate towards the individual lower lobe gas exchange. Objective measures of donor lung function may optimize donor surgeon assessment, allowing for low pulmonary graft dysfunction rates and low 90-day and 1-year mortality.

Donors with a prior history of cardiac surgery are a viable source of lung allografts

OBJECTIVES

End-stage lung disease continues to rise despite the lack of suitable lung donors, limiting the numbers of lung transplants performed each year. Expanded donor criteria, use of donation after cardiac death donors and the advent of ex vivo lung perfusion have resulted only in a slight increase in donor lung utilization. Organ donors with prior cardiac surgery (DPCS) present risks and technical challenges; however, they may be a potential source of suitable lung allografts with an experienced procurement surgeon. We present our experience having evaluated potential lung donors with a prior history of cardiac surgery, resulting in successful transplant outcomes.

METHODS

This is a single-institution retrospective review of brain-dead organ donors that were evaluated for lung donation in the period 2012-15. Donor and recipient characteristics were collected. Post-lung transplant survival was recorded.

RESULTS

From 2012 to 2015, 259 donors were evaluated, 12 with a prior history of cardiac surgery of which 4 had coronary artery bypass, 3 had aortic root replacement, 2 had aortic valve replacement, 1 pulmonary embolectomy, 1 two-time reoperative valve replacement and 1 paediatric congenital ventricular septal defect repair. DPCS, 6/12 (50% dry run) provided suitable allografts generating six single-lung transplants (three right and three left, 1 donor provided twin single-lung transplants) and one double-lung transplant. Interval between cardiac surgery and procurement for those rejected was median 5840 (IQR 2350-8640) days and interval for the donors that provided allografts was median 438 (IQR 336-1095) days (Mann-Whitney, P = 0.07). Recipient 1-year survival from DPCS is 100%. Recipient 1-year survival was 92% in allografts explanted from donors with no prior cardiac surgery (2012-13).

CONCLUSION

To date, this is the largest single-centre experience using lung allografts from brain-dead DPCS. Our experience shows despite predicted technical difficulties, with good communication between thoracic and abdominal teams, successful transplant outcomes are possible, when surgeons with experience in reoperative cases are sent for lung procurements.

Frailty Phenotypes, Disability, and Outcomes in Adult Candidates for Lung Transplantation

RATIONALE

Frailty is associated with morbidity and mortality in abdominal organ transplantation but has not been examined in lung transplantation.

OBJECTIVES

To examine the construct and predictive validity of frailty phenotypes in lung transplant candidates.

METHODS

In a multicenter prospective cohort, we measured frailty with the Fried Frailty Phenotype (FFP) and Short Physical Performance Battery (SPPB). We evaluated construct validity through comparisons with conceptually related factors. In a nested case-control study of frail and nonfrail subjects, we measured serum IL-6, tumor necrosis factor receptor 1, insulin-like growth factor I, and leptin. We estimated the association between frailty and disability using the Lung Transplant Valued Life Activities disability scale. We estimated the association between frailty and risk of delisting or death before transplant using multivariate logistic and Cox models, respectively.

MEASUREMENTS AND MAIN RESULTS

Of 395 subjects, 354 completed FFP assessments and 262 completed SPPB assessments; 28% were frail by FFP (95% confidence interval [CI], 24-33%) and 10% based on the SPPB (95% CI, 7-14%). By either measure, frailty correlated more strongly with exercise capacity and grip strength than with lung function. Frail subjects tended to have higher plasma IL-6 and tumor necrosis factor receptor 1 and lower insulin-like growth factor I and leptin. Frailty by either measure was associated with greater disability. After adjusting for age, sex, diagnosis, and transplant center, both FFP and SPPB were associated with increased risk of delisting or death before lung transplant. For every 1-point worsening in score, hazard ratios were 1.30 (95% CI, 1.01-1.67) for FFP and 1.53 (95% CI, 1.19-1.59) for SPPB.

CONCLUSIONS

Frailty is prevalent among lung transplant candidates and is independently associated with greater disability and an increased risk of delisting or death.

Body composition and mortality after adult lung transplantation in the United States

RATIONALE

Obesity and underweight are contraindications to lung transplantation based on their associations with mortality in studies performed before implementation of the lung allocation score (LAS)-based organ allocation system in the United States Objectives: To determine the associations of body mass index (BMI) and plasma leptin levels with survival after lung transplantation.

METHODS

We used multivariable-adjusted regression models to examine associations between BMI and 1-year mortality in 9,073 adults who underwent lung transplantation in the United States between May 2005 and June 2011, and plasma leptin and mortality in 599 Lung Transplant Outcomes Group study participants. We measured body fat and skeletal muscle mass using whole-body dual X-ray absorptiometry in 142 adult lung transplant candidates.

MEASUREMENTS AND MAIN RESULTS

Adjusted mortality rates were similar among normal weight (BMI 18.5-24.9 kg/m(2)), overweight (BMI 25.0-29.9), and class I obese (BMI 30-34.9) transplant recipients. Underweight (BMI < 18.5) was associated with a 35% increased rate of death (95% confidence interval, 10-66%). Class II-III obesity (BMI ≥ 35 kg/m(2)) was associated with a nearly twofold increase in mortality (hazard ratio, 1.9; 95% confidence interval, 1.3-2.8). Higher leptin levels were associated with increased mortality after transplant surgery performed without cardiopulmonary bypass (P for interaction = 0.03). A BMI greater than or equal to 30 kg/m(2) was 26% sensitive and 97% specific for total body fat-defined obesity.

CONCLUSIONS

A BMI of 30.0-34.9 kg/m(2) is not associated with 1-year mortality after lung transplantation in the LAS era, perhaps because of its low sensitivity for obesity. The association between leptin and mortality suggests the need to validate alternative methods to measure obesity in candidates for lung transplantation. A BMI greater than or equal to 30 kg/m(2) may no longer contraindicate lung transplantation.

Inflammatory bowel disease and exercise: results of a Crohn's and Colitis UK survey

BACKGROUND

Over 250 000 people in the UK are affected with inflammatory bowel disease (IBD) and approximately 10 000 new cases are diagnosed every year. These chronic bowel conditions have been shown to affect both work and recreational activity. In the general population, regular exercise has numerous benefits to health and well-being and there are additional benefits for those with IBD. However, people with IBD face significant challenges in trying to take regular exercise.

OBJECTIVE

With the renewed focus on sport brought about by the recent London Olympics, Crohn's and Colitis UK surveyed its members to explore their sport and fitness habits.

METHODS

918 members participated in the survey, which is the largest survey of its kind, investigating the exercise habits of people with IBD.

RESULTS

The survey showed widespread uptake of exercise in those with IBD, with a large number feeling better for it. However, it also identified a considerable number of respondents who reported a significant negative impact of IBD on their ability to take up, enjoy and derive benefit from sporting activities.

CONCLUSION

Asking questions about sporting leisure activity in clinical consultations may identify those in need of help and support and possibly identify factors to be dealt with, in order to enable them to take part in these beneficial activities.

Donor surfactant protein D (SP-D) polymorphisms are associated with lung transplant outcome

Chronic lung allograft dysfunction (CLAD) is the major factor limiting long-term success of lung transplantation. Polymorphisms of surfactant protein D (SP-D), an important molecule within lung innate immunity, have been associated with various lung diseases. We investigated the association between donor lung SP-D polymorphisms and posttransplant CLAD and survival in 191 lung transplant recipients consecutively transplanted. Recipients were prospectively followed with routine pulmonary function tests. Donor DNA was assayed by pyrosequencing for SP-D polymorphisms of two single-nucleotide variations altering amino acids in the mature protein N-terminal domain codon 11 (Met(11) Thr), and in codon 160 (Ala(160) Thr) of the C-terminal domain. CLAD was diagnosed in 88/191 patients, and 60/191 patients have died. Recipients of allografts that expressed the homozygous Met(11) Met variant of aa11 had significantly greater freedom from CLAD development and better survival compared to those with the homozygous Thr(11) Th variant of aa11. No significant association was noted for SP-D variants of aa160. Lung allografts with the SP-D polymorphic variant Thr(11) Th of aa11 are associated with development of CLAD and reduced survival. The observed genetic differences of the donor lung, potentially with their effects on innate immunity, may influence the clinical outcomes after lung transplantation.

74 GERM CELLS AND TESTICULAR SOMATIC CELLS HAVE DIFFERENT SENSITIVITY TO CRYOPRESERVATION

Spermatogonial stem cells (SSC) are the foundation of spermatogenesis. Undifferentiated spermatogonia, containing SSC, represent only 2 to 5% of cells recovered from immature mammalian testis. Cryopreservation in liquid nitrogen allows for long-term storage of cells. Preservation of germ cells can serve as a means of genetic preservation from immature males when sperm storage is not an option. Studies have investigated the effects of cryopreservation on the spermatogenic potential of SSC and the efficiency of various cryopreservation protocols. Preliminary observations indicated that germ cells may survive cryopreservation better than testicular somatic cells, resulting in a post-thaw cell population enriched in germ cells. However, this has not been critically evaluated. The objective of this study was to test the hypothesis that germ cells are less susceptible to cryo-damage than testicular somatic cells. Cells were harvested from the testes of 1-wk-old piglets by 2-step enzymatic digestion. The initial cell suspension was subjected to differential adhesion to enrich the cell population for germ cells. Cells were plated in DMEM + 5% fetal bovine serum and incubated at 37°C in 5% CO2 in air. After 18 h, cells in suspension and cells slightly attached were recovered by trypsinization (1 : 10 trypsin-ethylenediaminetetraacetic acid) for 30 s and replated. This was repeated 24 and 36 h after initial plating. The enriched population was placed into cryovials at a concentration of 30 × 106 cells in freezing media (70% DMEM + 20% fetal bovine serum + 10% dimethyl sulfoxide), kept for 24 h at –80°C in a cryogenic freezing container and transferred to liquid nitrogen for 1 week. Aliquots of cells before freezing and after thawing at 37°C followed by incubation at 37°C in 5% CO2 in air for 1 h were analyzed for viability by propidium iodide (PI) exclusion and immunofluorescence for the germ cell marker VASA to identify viable germ cells (VASA+/PI–), nonviable germ cells (VASA+/PI+), viable somatic cells (VASA–/PI–), and nonviable somatic cells (VASA–/PI+). The percentage of viable germ cells after freezing and thawing was compared to the percentage of viable somatic cells by ANOVA. After enrichment by differential plating, the cell population had 95.6 ± 0.9% viability and contained 27.1 ± 7.4% germ cells (n = 3 replicates). After cryopreservation, the overall cell viability was 77.5 ± 1.6%, and 25.8 ± 8.0% were germ cells. The overall viability after cryopreservation could potentially have benefited from the 1-h incubation prior to analysis. The viability of the germ cell population after freezing and thawing was higher (92.1 ± 3.1%) than somatic cell viability (72.3 ± 1.7%; P < 0.01). These results indicate that porcine germ cells survive cryopreservation better than do testicular somatic cells. Therefore, cryostorage of germ cells can be an efficient means for preservation of male genetic material. Supported by NIH ORIP/DCM RR17359.

Sequential medical trials

A model for sequential clinical trials is discussed. Three proposed stopping rules are studied by the Monte Carlo method for small patient horizons and mathematically for large patient horizons. They are shown to be about equally effective and asymptotically optimal from both Bayesian and frequentist points of view and are markedly superior to any fixed sample size procedure.