BACKGROUND:Accumulated knowledge on the outcomes related to size mismatch in lung transplantation derives from predicted total lung capacity equations rather than individualized measurements of donors and recipients. The increasing availability of computed tomography (CT) makes it possible to measure the lung volumes of donors and recipients before transplantation. We hypothesize that CT-derived lung volumes predict a need for surgical graft reduction and primary graft dysfunction.METHODS:Donors from the local organ procurement organization and recipients from our hospital from 2012 to 2018 were included if their CT exams were available. The CT lung volumes and plethysmography total lung capacity were measured and compared with predicted total lung capacity using Bland Altman methods. We used logistic regression to predict the need for surgical graft reduction and ordinal logistic regression to stratify the risk for primary graft dysfunction.RESULTS:A total of 315 transplant candidates with 575 CT scans and 379 donors with 379 CT scans were included. The CT lung volumes closely approximated plethysmography lung volumes and differed from the predicted total lung capacity in transplant candidates. In donors, CT lung volumes systematically underestimated predicted total lung capacity. Ninety-four donors and recipients were matched and transplanted locally. Larger donor and smaller recipient lung volumes estimated by CT predicted a need for surgical graft reduction and were associated with higher primary graft dysfunction grade.CONCLUSION:The CT lung volumes predicted the need for surgical graft reduction and primary graft dysfunction grade. Adding CT-derived lung volumes to the donor-recipient matching process may improve recipients' outcomes.

Background: Errors in measuring chest X-ray (CXR) lung heights could contribute to the occurrence of size-mismatched lung transplant procedures. Methods: We first used Bland-Altman analysis for repeated measures to evaluate contributors to measurement error of chest X-ray lung height. We then applied error propagation theory to assess the impact of measurement error on size matching for lung transplantation. Results: A total 387 chest X-rays from twenty-five donors and twenty-five recipients were measured by two raters. Individual standard deviation for lung height differences were independent of age, sex, donor vs. recipient, diagnostic group and race/ethnicity and all were pooled for analysis. Bias between raters was 0.27 cm (±0.03) and 0.22 cm (±0.06) for the right and left lung respectively. Within subject variability was the biggest contributor to error in measurement, 2.76 cm (±0.06) and 2.78 cm (±0.2) for the right and left lung height. A height difference of 4.4 cm or more (95% CI: ±4.2, ±4.6 cm) between the donor and the recipient right lung height has to be accepted to ensure matching for at least 95% of patients with the same true lung height. This difference decreases to ±1.1 cm (95% CI: ±0.9, ±1.3 cm) when the average from all available chest X-rays is used. The probability of matching a donor and a recipient decreases with increasing true lung height difference. Conclusions: Individual chest X-ray lung heights are imprecise for the purpose of size matching in lung transplantation. Averaging chest X-rays lung heights reduced uncertainty.

BACKGROUND: Mechanical ventilation immediately after lung transplantation may impact the development of primary graft dysfunction (PGD), particularly in cases of donor-recipient size mismatch as ventilation is typically based on recipient rather than donor size. METHODS: We conducted a retrospective cohort study of adult bilateral lung transplant recipients at our center between January 2010 and January 2017. We defined donor-based lung protective ventilation (dLPV) as 6 to 8 ml/kg of donor ideal body weight and plateau pressure <30 cm H2O. We calculated the donor-recipient predicted total lung capacity (pTLC) ratio and used logistic regression to examine relationships between pTLC ratio, dLPV and PGD grade 3 at 48 to 72 hours. We used Cox proportional hazards modelling to examine the relationship between pTLC ratio, dLPV and 1-year survival. RESULTS: The cohort included 373 recipients; 24 (6.4%) developed PGD grade 3 at 48 to 72 hours, and 213 (57.3%) received dLPV. Mean pTLC ratio was 1.04 +/- 0.18. dLPV was associated with significantly lower risks of PGD grade 3 (OR = 0.44; 95% CI: 0.29-0.68, p < 0.001) and 1-year mortality (HR = 0.49; 95% CI: 0.29-0.8, p = 0.018). There was a significant association between pTLC ratio and the risk of PGD grade 3, but this was attenuated by the use of dLPV. CONCLUSIONS: dLPV is associated with decreased risk of PGD grade 3 at 48 to 72 hours and decreased 1-year mortality. Additionally, dLPV attenuates the association between pTLC and both PGD grade 3 and 1-year mortality. Donor-based ventilation strategies may help to mitigate the risk of PGD and other adverse outcomes associated with size mismatch after lung transplantation. (C) 2021 International Society for Heart and Lung Transplantation. All rights reserved.

Higher tidal volumes and not receiving lung protective ventilation were associated with an increased risk of PGD 3 between 24 and 72 hours. This suggests that adjusting ventilator settings based on donor size and lung protective ventilation after transplantation may mitigate the risk of PGD.

BACKGROUND:Over the last decade two alternative models of donor care have emerged in the United States: the conventional model, whereby donors are managed at the hospital where brain death occurs, and the specialized donor care facility (SDCF), in which brain dead donors are transferred to a SDCF for medical optimization and organ procurement. Despite increasing use of the SDCF model, its cost-effectiveness in comparison to the conventional model remains unknown.METHODS:We performed an economic evaluation of the SDCF and conventional model of donor care from the perspective of U.S. transplant centers over a 2-year study period. In this analysis, we utilized nationwide data from the Scientific Registry of Transplant Recipients and controlled for donor characteristics and patterns of organ sharing across the nation's organ procurement organizations (OPOs). Subgroup analysis was performed to determine the impact of the SDCF model on thoracic organ transplants.RESULTS:A total of 38,944 organ transplants were performed in the U.S. during the study period from 13,539 donors with an observed total organ cost of $1.36 billion. If every OPO assumed the cost and effectiveness of the SDCF model, a predicted 39,155 organ transplants (+211) would have been performed with a predicted total organ cost of $1.26 billion (-$100 million). Subgroup analysis of thoracic organs revealed that the SDCF model would lead to a predicted 156 additional transplants with a cost saving of $24.6 million.CONCLUSIONS:The U.S. SDCF model may be a less costly and more effective means of multi-organ donor management, particularly for thoracic organ donors, compared to the conventional hospital-based model.

Objective: Chest computed tomography (CT) imaging is being increasingly used for potential lung donor assessment. However, the efficacy of CT imaging in this setting remains unknown. We hypothesize that chest CT imaging independently affects the decision-making process in donor lung utilization. Methods: We conducted a retrospective cohort study of all adult donation after brain death donors managed through our local organ procurement organization from June 2011 to November 2016. An experienced thoracic radiologist independently reviewed donor chest CTand chest x-ray images in a blinded, standardized manner to determine the presence of structural lung disease (eg, emphysema, interstitial lung disease [ILD]) and acute abnormalities (eg, traumatic lung injury [TLI]). Distinct models of lung utilization were fit to groups with initial partial pressure of oxygen (iPaO(2)) <= 300 mm Hg (suboptimal) and iPaO(2) > 300 mm Hg (optimal). Results: The organ procurement organization managed 753 donors during the study period, with a lung utilization rate ([lung donors/all organ donors] x 100) of 36.5% (275 of 753). Four hundred forty-five (59.1%) donors received chest CT imaging, revealing emphysema (13.7%), ILD (2.5%), and TLI (7.2%). In univariate analysis, findings of TLI (odds ratio [OR], 2.23; 95% confidence interval [CI], 1.08-4.61) were positively associated with lung utilization, whereas findings of emphysema (OR, 0.18; CI, 0.08-0.40) were negatively associated with utilization. In multivariate analysis, CT findings of emphysema (OR, 0.21; CI 0.08-0.54) remained negatively associated with utilization. No potential donors with CT findings of ILD became lung donors. After controlling for chest x-ray findings, chest CT imaging findings of structural lung disease remained negatively associated with utilization (P = .0001). Lung utilization rate in the suboptimal and optimal iPaO(2) populations was 35.1% and 41.4%, respectively, and CT findings of emphysema had a significant association with nonutilization in both groups. Conclusions: In the evaluation of potential lung donors, chest CT imaging findings of structural lung disease, such as emphysema and ILD, have a significant negative association with lung utilization. Our findings suggest that chest CT imaging might be an important adjunct to conventional lung donor assessment criteria.

BACKGROUND:Improved understanding of lung transplant disease states is essential because failure rates are high, often due to chronic lung allograft dysfunction. However, histologic assessment of lung transplant transbronchial biopsies (TBBs) is difficult and often uninterpretable even with 10 pieces. METHODS:We prospectively studied whether microarray assessment of single TBB pieces could identify disease states and reduce the amount of tissue required for diagnosis. By following strategies successful for heart transplants, we used expression of rejection-associated transcripts (annotated in kidney transplant biopsies) in unsupervised machine learning to identify disease states. RESULTS:All 242 single-piece TBBs produced reliable transcript measurements. Paired TBB pieces available from 12 patients showed significant similarity but also showed some sampling variance. Alveolar content, as estimated by surfactant transcript expression, was a source of sampling variance. To offset sampling variation, for analysis, we selected 152 single-piece TBBs with high surfactant transcripts. Unsupervised archetypal analysis identified 4 idealized phenotypes (archetypes) and scored biopsies for their similarity to each: normal; T-cell‒mediated rejection (TCMR; T-cell transcripts); antibody-mediated rejection (ABMR)-like (endothelial transcripts); and injury (macrophage transcripts). Molecular TCMR correlated with histologic TCMR. The relationship of molecular scores to histologic ABMR could not be assessed because of the paucity of ABMR in this population. CONCLUSIONS:Molecular assessment of single-piece TBBs can be used to classify lung transplant biopsies and correlated with rejection histology. Two or 3 pieces for each TBB will probably be needed to offset sampling variance.

Purpose This study aimed to classify and grade airway complications after lung transplant and to evaluate the risk of airway complications associated with antifibrotic use at a single lung transplant center. Methods All cases of lung transplantation at Barnes-Jewish Hospital between 1/1/2015 and 5/31/2018 were reviewed. Airway complications were graded using the 2018 ISHLT Consensus Statement on Adult Anastomotic Airway Complications. Antifibrotic use within 2 weeks of transplant was evaluated for association with airway complications by logistic regression. Results Based on the ISHLT Consensus definition, 159/261 patients (60.9%) had an airway complication; among these, only 20 (7.6%) were considered severe. There was no association between diagnosis for transplant and the development of an airway complication. AF use was associated with severe ischemic airway complication; among 58 who were on an AF agent pre-transplant, 8 (13.8%) developed an airway complication after transplant (odds ratio [OR] 2.547; 95% confidence interval [CI], 0.988 to 6.567; p = 0.053). This association was significant for nintedanib (OR 3.767; 95% CI, 1.119 to 12.681; p = 0.032) but not pirfenidone (OR 1.471; 95% CI, 0.465 to 4.660; p = 0.511). AF use was also associated with development of anastomotic stenosis; 14/58 (24.1%) developed anastomotic stenosis (OR 2.074; 95% CI, 1.004 to 4.283; p = 0.049). This association was not significant for nintedanib (OR 2.044; 95% CI, 0.693 to 6.022; p = 0.195) or pirfenidone (OR 1.781; 95% CI, 0.774 to 4.100; p = 0.175). AF use was not associated with anastomotic dehiscence; 8/58 (13.8%) developed a dehiscence (OR 1.139; 95% CI, 0.484 to 2.681; p = 0.765). Conclusion The grading system proposed by the 2018 ISHLT Consensus Statement led to identification of airway complication in >60% of lung transplants in this cohort, but most were considered mild and did not require intervention. Antifibrotic use was associated with increased risk of severe ischemic airway complications and anastomotic stenosis. This study aimed to classify and grade airway complications after lung transplant and to evaluate the risk of airway complications associated with antifibrotic use at a single lung transplant center. All cases of lung transplantation at Barnes-Jewish Hospital between 1/1/2015 and 5/31/2018 were reviewed. Airway complications were graded using the 2018 ISHLT Consensus Statement on Adult Anastomotic Airway Complications. Antifibrotic use within 2 weeks of transplant was evaluated for association with airway complications by logistic regression. Based on the ISHLT Consensus definition, 159/261 patients (60.9%) had an airway complication; among these, only 20 (7.6%) were considered severe. There was no association between diagnosis for transplant and the development of an airway complication. AF use was associated with severe ischemic airway complication; among 58 who were on an AF agent pre-transplant, 8 (13.8%) developed an airway complication after transplant (odds ratio [OR] 2.547; 95% confidence interval [CI], 0.988 to 6.567; p = 0.053). This association was significant for nintedanib (OR 3.767; 95% CI, 1.119 to 12.681; p = 0.032) but not pirfenidone (OR 1.471; 95% CI, 0.465 to 4.660; p = 0.511). AF use was also associated with development of anastomotic stenosis; 14/58 (24.1%) developed anastomotic stenosis (OR 2.074; 95% CI, 1.004 to 4.283; p = 0.049). This association was not significant for nintedanib (OR 2.044; 95% CI, 0.693 to 6.022; p = 0.195) or pirfenidone (OR 1.781; 95% CI, 0.774 to 4.100; p = 0.175). AF use was not associated with anastomotic dehiscence; 8/58 (13.8%) developed a dehiscence (OR 1.139; 95% CI, 0.484 to 2.681; p = 0.765). The grading system proposed by the 2018 ISHLT Consensus Statement led to identification of airway complication in >60% of lung transplants in this cohort, but most were considered mild and did not require intervention. Antifibrotic use was associated with increased risk of severe ischemic airway complications and anastomotic stenosis.

Purpose We aimed to identify clinical predictors of a favorable response to treatment with extracorporeal photopheresis (ECP) in lung transplant (Tx) recipients with CLAD. Methods Lung Tx recipients followed at Barnes-Jewish Hospital treated with ECP for CLAD were retrospectively identified. Patient characteristics, forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were recorded for the 6 month(mo)s prior to and 12 mos after initiation of ECP. FEV1 was plotted vs. time, and a linear regression line was drawn through the data points. The slope (ml/mo) of the linear regression line was compared pre- and post- ECP using the Wilcoxon signed rank test. FEV1 and FVC were recorded as 0 at the time of re-Tx or death. A favorable response was defined as post-ECP FEV1 slope (ml/mo) > 0. Univariate and multivariable logistic regression models were created to identify covariates associated with a favorable response. Results 208 lung Tx recipients treated with ECP for CLAD between 11/1991-4/2017 were identified. During the study period, 16 patients were treated with 2 separate courses of ECP, totaling 223 ECP treatment courses. Recipient, donor and transplant characteristics are listed in Table 1. The median time to initiation of ECP from date of Tx was 1286.0 days (IQR: 646.8-2839.5). The median rate of change in FEV1 was -94.78 ml/mo (-195.88 ∼ -48.24) pre-ECP, and -13.74 ml/mo (-43.04 ∼ 0.98) post-ECP (p<0.001). 58/223 (26.0%) treatment courses met criteria for a favorable response. Complications developed in 15 (6.7%) patients and were mostly catheter related. In univariate and multivariable logistic regression, none of the covariates (age, gender, primary diagnosis, rate of FEV1 decline pre-ECP, time from Tx, time from BOS diagnosis, RAS, early BOS) were significantly associated with response. Conclusion Over 25% of patients with CLAD had a favorable response with an improvement in FEV1 in the 12 mos after ECP initiation. However, we could not identify clinical predictors of a favorable response.

Kartagener's syndrome is a rare genetic disorder of ciliated epithelial cells associated with recurrent respiratory tract infections, bronchiectasis, and situs inversus. In some patients, the accumulation of airway secretions and recurrent infections lead to end-stage lung disease, for which lung transplantation is the only effective treatment. Anatomical variations, such as dextrocardia and pulmonary situs inversus, make the procedure challenging, yet feasible with certain technical modifications and careful preparation of donor lungs. We report a case of bilateral lung transplantation without the use of cardiopulmonary bypass in a patient with Kartagener's syndrome while describing important technical details of the operation. (C) 2019 by The Society of Thoracic Surgeons

Purpose Chronic lung allograft dysfunction (CLAD) is a clinical/functional diagnosis that cannot be defined by histology in transbronchial biopsies (TBBs). Moreover, understanding the biology of CLAD is crucial for prevention and potential treatment. We studied gene expression associated with CLAD in TBBs, but also studied mucosal biopsies from the third bronchial bifurcation (3BMBs). Methods 223 highly alveolated TBBs (54 CLAD, 169 no CLAD) and 182 3BMBs (43 CLAD, 139 no CLAD) were collected from 7 centers and processed on microarrays. The top 100 non-overlapping genes associated with a diagnosis of CLAD prior to biopsy were identified, annotated, and used for gene set analysis and gene ontology (GO) biological process analysis. Results The top genes associated with CLAD reflected de-differentiation (expression loss), injury (expression gain), and inflammation in both TBBs and 3BMBs. These associations were stronger in 3BMBs. Pathway analysis using the top genes also suggested parenchymal de-differentiation (e.g. loss of transcriptional regulation and mitochondrial function in TBBs) and inflammatory pathway activation, particularly in 3BMBs (Table 1). Gene sets previously annotated in atrophy-scarring, including immunoglobulin transcripts (plasma cells), were elevated in CLAD in TBBs and 3BMBs, but 3BMBs also showed more inflammation-related changes (e.g. interferon gamma effects). Conclusion Molecular changes associated with CLAD were apparent in TBBs and especially in 3BMBs, and indicate that CLAD is a combination of atrophy/scarring, function loss, and, particularly in 3BMBs, inflammation. Molecular assessment of 3BMBs is a particularly promising opportunity to dissect CLAD biology and potentially gain insight into the BOS variant. ClinicalTrials.gov: NCT02812290 Chronic lung allograft dysfunction (CLAD) is a clinical/functional diagnosis that cannot be defined by histology in transbronchial biopsies (TBBs). Moreover, understanding the biology of CLAD is crucial for prevention and potential treatment. We studied gene expression associated with CLAD in TBBs, but also studied mucosal biopsies from the third bronchial bifurcation (3BMBs). 223 highly alveolated TBBs (54 CLAD, 169 no CLAD) and 182 3BMBs (43 CLAD, 139 no CLAD) were collected from 7 centers and processed on microarrays. The top 100 non-overlapping genes associated with a diagnosis of CLAD prior to biopsy were identified, annotated, and used for gene set analysis and gene ontology (GO) biological process analysis. The top genes associated with CLAD reflected de-differentiation (expression loss), injury (expression gain), and inflammation in both TBBs and 3BMBs. These associations were stronger in 3BMBs. Pathway analysis using the top genes also suggested parenchymal de-differentiation (e.g. loss of transcriptional regulation and mitochondrial function in TBBs) and inflammatory pathway activation, particularly in 3BMBs (Table 1). Gene sets previously annotated in atrophy-scarring, including immunoglobulin transcripts (plasma cells), were elevated in CLAD in TBBs and 3BMBs, but 3BMBs also showed more inflammation-related changes (e.g. interferon gamma effects). Molecular changes associated with CLAD were apparent in TBBs and especially in 3BMBs, and indicate that CLAD is a combination of atrophy/scarring, function loss, and, particularly in 3BMBs, inflammation. Molecular assessment of 3BMBs is a particularly promising opportunity to dissect CLAD biology and potentially gain insight into the BOS variant. ClinicalTrials.gov: NCT02812290

Purpose CARV infections are associated with an increased risk of CLAD development and progression. Inhaled corticosteroids are used to treat airway inflammation, but there is a dearth of data regarding their use in lung transplantation. This study aimed to examine the effect of inhaled beclomethasone on the development and progression of CLAD after CARV. Methods Single-center, double blind, pilot, randomized, placebo controlled trial of inhaled beclomethasone in adult LTR diagnosed with a CARV between Jan 2017 and Dec 2017. Patients were randomized in a 1:1 ratio stratified by BOS stage (BOS 0/0p vs 1/2) within 7 days of CARV. Study drug was continued for 6 months. The primary endpoint was freedom from new or progressive CLAD (defined as a 15% decline in pre CARV FEV1). Secondary endpoints included all-cause mortality and development of new DSA post-CARV. Results 7 patients were randomized to inhaled beclomethasone and 8 to placebo. Baseline demographics were well matched between groups including gender, age at LTR, time from LTR to CARV, upper vs lower CARV, BOS stage, and DSA at the time of study enrollment (Table 1). There was no difference in freedom from CLAD or CLAD progression between the 2 groups (Figure 1). No patients died or developed new DSA during the study period. Conclusion Inhaled beclomethasone was not associated with a lower incidence of new or progressive CLAD after CARV when compared to placebo. However, this study had limited power and sample size. Additional studies are necessary to assess the potential benefit of inhaled corticosteroids in LTR after CARV.

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.

Previous data have shown reduced survival in older (≥65 years) recipients after lung transplantation (LTx). We aimed to evaluate short- and long-term outcomes and causes of death (COD) in older LTx recipients. We hypothesized that older patients are more likely to die from infection than rejection because of immune senescence.

Histologic assessment of T-cell mediated rejection (TCMR) in lung transplant (LTx) transbronchial biopsies (TBB) has unacceptable interobserver variability (intrinsic errors), and cannot assess antibody mediated rejection (ABMR). Molecular phenotyping of biopsies with microarrays has been successful in kidney and heart transplants. We sought to standardize its use in TBB.

BACKGROUND:Lung transplant (LTx) recipients have low long-term survival and a high incidence of bronchiolitis obliterans syndrome (BOS). However, few long-term, multicenter, and precise estimates of BOS-free survival (a composite outcome of death or BOS) incidence exist. METHODS:This retrospective cohort study of primary LTx recipients (1994-2011) reported to the International Society of Heart and Lung Transplantation Thoracic Transplant Registry assessed outcomes through 2012. For the composite primary outcome of BOS-free survival, we used Kaplan-Meier survival and Cox proportional hazards regression, censoring for loss to follow-up, end of study, and re-LTx. Although standard Thoracic Transplant Registry analyses censor at the last consecutive annual complete BOS status report, our analyses allowed for partially missing BOS data. RESULTS:Due to BOS reporting standards, 99.1% of the cohort received LTx in North America. During 79,896 person-years of follow-up, single LTx (6,599 of 15,268 [43%]) and bilateral LTx (8,699 of 15,268 [57%]) recipients had a median BOS-free survival of 3.16 years (95% confidence interval [CI], 2.99-3.30 years) and 3.58 years (95% CI, 3.53-3.72 years), respectively. Almost 90% of the single and bilateral LTx recipients developed the composite outcome within 10 years of transplantation. Standard Registry analyses "overestimated" median BOS-free survival by 0.42 years and "underestimated" the median survival after BOS by about a half-year for both single and bilateral LTx (p < 0.05). CONCLUSIONS:Most LTx recipients die or develop BOS within 4 years, and very few remain alive and free from BOS at 10 years post-LTx. Less inclusive Thoracic Transplant Registry analytic methods tend to overestimate BOS-free survival. The Registry would benefit from improved international reporting of BOS and other chronic lung allograft dysfunction (CLAD) events.

Lung transplantation is the final treatment option for patients with end stage lung disease. Increasingly, this therapy is being offered to patients of advanced age. In the most recent ISHLT registry report, approximately 20% of lung transplant recipients were 66 years of age or older. Previous studies investigating outcomes in older patients have included primarily patients over age 65. We sought to examine the outcomes of lung transplantation specifically in patients older than 70 years of age.

Histologic assessment of rejection in transbronchial biopsies (TBB) from lung transplant recipients (LTxR) has unacceptable interobserver variability and poses risk that excludes the sickest patients. Mucosal biopsies (MB) are safer, but cannot be interpreted by histology. Based on success in kidney and heart transplants, we evaluated a molecular system for assessing rejection-like changes in MB.