Development and validation of primary graft dysfunction predictive algorithm for lung transplant candidates

BACKGROUND

Primary graft dysfunction (PGD) is the leading cause of early morbidity and mortality after lung transplantation. Accurate prediction of PGD risk could inform donor approaches and perioperative care planning. We sought to develop a clinically useful, generalizable PGD prediction model to aid in transplant decision-making.

METHODS

We derived a predictive model in a prospective cohort study of subjects from 2012 to 2018, followed by a single-center external validation. We used regularized (lasso) logistic regression to evaluate the predictive ability of clinically available PGD predictors and developed a user interface for clinical application. Using decision curve analysis, we quantified the net benefit of the model across a range of PGD risk thresholds and assessed model calibration and discrimination.

RESULTS

The PGD predictive model included distance from donor hospital to recipient transplant center, recipient age, predicted total lung capacity, lung allocation score (LAS), body mass index, pulmonary artery mean pressure, sex, and indication for transplant; donor age, sex, mechanism of death, and donor smoking status; and interaction terms for LAS and donor distance. The interface allows for real-time assessment of PGD risk for any donor/recipient combination. The model offers decision-making net benefit in the PGD risk range of 10% to 75% in the derivation centers and 2% to 10% in the validation cohort, a range incorporating the incidence in that cohort.

CONCLUSION

We developed a clinically useful PGD predictive algorithm across a range of PGD risk thresholds to support transplant decision-making, posttransplant care, and enrich samples for PGD treatment trials.

The Association of Post-Lung Transplant Pulmonary Embolism With the Development of Chronic Lung Allograft Dysfunction

Background

Pulmonary embolism (PE) is a rare yet serious postoperative complication for lung transplant recipients (LTRs). The association between timing and severity of PE and the development of chronic allograft lung dysfunction (CLAD) has not been described.

Methods

A single-center, retrospective cohort analysis of first LTRs included bilateral or single lung transplants and excluded multiorgan transplants and retransplants. PEs were confirmed by computed tomography angiography or ventilation/perfusion (VQ) scans. Infarctions were confirmed on computed tomography angiography by a trained physician. The PE severity was defined by the Pulmonary Embolism Severity Index (PESI) score, a 30-d post-PE mortality risk calculator, and stratified by low I and II (0-85), intermediate III and IV (85-125), and high V (>125). PE and PESI were analyzed in the outcomes of overall survival, graft failure, and chronic lung allograft dysfunction (CLAD).

Results

We identified 57 of 928 patients (6.14%) who had at least 1 PE in the LTR cohort with a median follow-up of 1623 d. In the subset with PE, the median PESI score was 85 (75.8-96.5). Most of the PESI scores (32/56 available) were in the low-risk category. In the CLAD analysis, there were 49 LTRs who had a PE and 16 LTRs (33%) had infarction. When treating PE as time-dependent and adjusting for covariates, PE was significantly associated with death (hazard ratio [HR] 1.8; 95% confidence interval [CI], 1.3-2.5), as well as increased risk of graft failure, defined as retransplant, CLAD, or death (HR 1.8; 95% CI, 1.3-2.5), and CLAD (HR 1.7; 95% CI, 1.2-2.4). Infarction was not associated with CLAD or death. The PESI risk category was not a significant predictor of death or CLAD.

Conclusions

PE is associated with decreased survival and increased hazard of developing CLAD. PESI score was not a reliable predictor of CLAD or death in this lung transplant cohort.

The Impact of Donor Smoking on Primary Graft Dysfunction and Mortality after Lung Transplantation

Rationale: Primary graft dysfunction (PGD) is the leading cause of early morbidity and mortality after lung transplantation. Prior studies implicated proxy-defined donor smoking as a risk factor for PGD and mortality. Objectives: We aimed to more accurately assess the impact of donor smoke exposure on PGD and mortality using quantitative smoke exposure biomarkers. Methods: We performed a multicenter prospective cohort study of lung transplant recipients enrolled in the Lung Transplant Outcomes Group cohort between 2012 and 2018. PGD was defined as grade 3 at 48 or 72 hours after lung reperfusion. Donor smoking was defined using accepted thresholds of urinary biomarkers of nicotine exposure (cotinine) and tobacco-specific nitrosamine (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanol [NNAL]) in addition to clinical history. The donor smoking-PGD association was assessed using logistic regression, and survival analysis was performed using inverse probability of exposure weighting according to smoking category. Measurements and Main Results: Active donor smoking prevalence varied by definition, with 34-43% based on urinary cotinine, 28% by urinary NNAL, and 37% by clinical documentation. The standardized risk of PGD associated with active donor smoking was higher across all definitions, with an absolute risk increase of 11.5% (95% confidence interval [CI], 3.8% to 19.2%) by urinary cotinine, 5.7% (95% CI, -3.4% to 14.9%) by urinary NNAL, and 6.5% (95% CI, -2.8% to 15.8%) defined clinically. Donor smoking was not associated with differential post-lung transplant survival using any definition. Conclusions: Donor smoking associates with a modest increase in PGD risk but not with increased recipient mortality. Use of lungs from smokers is likely safe and may increase lung donor availability. Clinical trial registered with www.clinicaltrials.gov (NCT00552357).

With Comparable Outcomes, Should Early-Stage Lung Cancer Be a Contraindication to Lung Transplant?

BACKGROUND

Active primary lung malignancy remains a strong contraindication to lung transplantation (LTx). However, outcomes are unclear for patients with early-stage non-small cell lung cancer (NSCLC) who undergo LTx. We hypothesize that patients with early-stage NSCLC incidentally discovered in the explanted lungs have survival comparable to LTx recipients without incidental cancer identified.

METHODS

We performed a single-center retrospective analysis of all LTx recipients from May 2007 to September 2021 with incidental cancer identified in the explanted lungs by pathologist report. Survival statistics were estimated using Kaplan-Meier analysis.

RESULTS

Of the 1586 LTx performed, 23 patients (1.5%) were found to have incidental lung cancer in the explanted lungs. The most common indications for LTx were interstitial lung disease (n = 13) and chronic obstructive pulmonary disease (n = 7), and the most common histologic diagnosis was adenocarcinoma (n = 14). In the cohort with stage I disease (n = 9), the 1- and 5-year unadjusted Kaplan-Meier survival rates were 88.9% and 51.9%, respectively. The 1- and 5-year survival rates for transplant recipients without incidental cancer findings at LTx during this period were 86.7% and 59.4%, respectively, and did not differ significantly between the 2 strata (P = .96).

CONCLUSIONS

Survival rates at 1 and 5 years were comparable between LTx recipients with incidentally noted pathologic stage I NSCLC and contemporary recipients without cancer. All cancer-related deaths occurred in recipients with incidentally noted advanced NSCLC. These results suggest that patients with pathologic stage I lung cancer at the time of transplant have outcomes comparable to those without cancer findings at the time of transplant.

External Control Arms in Idiopathic Pulmonary Fibrosis Using Clinical Trial and Real-World Data Sources

Rationale: Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease for which novel therapies are needed. External controls (ECs) could enhance IPF trial efficiency, but the direct comparability of ECs versus concurrent controls is unknown. Objectives: To develop IPF ECs by fit-for-purpose data standards to historical randomized clinical trial (RCT), multicenter registry (Pulmonary Fibrosis Foundation Patient Registry), and electronic health record (EHR) data and to evaluate endpoint comparability among ECs and the phase II RCT of BMS-986020. Methods: After data curation, the rate of change in FVC from baseline to 26 weeks among participants receiving BMS-986020 600 mg twice daily was compared with the BMS-placebo arm and ECs using mixed-effects models with inverse probability weights. Measurements and Main Results: At 26 weeks, the rates of change in FVC were -32.71 ml for BMS-986020 and -130.09 ml for BMS-placebo (difference, 97.4 ml; 95% confidence interval [CI], 24.6-170.2), replicating the original BMS-986020 RCT. RCT ECs showed treatment effect point estimates within the 95% CI of the original BMS-986020 RCT. Pulmonary Fibrosis Foundation Patient Registry ECs and EHR ECs experienced a slower rate of FVC decline compared with the BMS-placebo arm, resulting in treatment-effect point estimates outside of the 95% CI of the original BMS-986020 RCT. Conclusions: IPF ECs generated from historical RCT placebo arms result in comparable primary treatment effects to that of the original clinical trial, whereas ECs from real-world data sources, including registry or EHR data, do not. RCT ECs may serve as a potentially useful supplement to future IPF RCTs.

Evaluation of host cellular responses to Epstein-Barr virus (EBV) in adult lung transplant patients with EBV-associated diseases

Epstein-Barr virus (EBV) reactivation is commonly observed in lung transplant recipients (LTRs). However, cellular immune responses to EBV in adult LTRs have not been well described. We aimed to study CD4/CD8 ratio, EBV-specific T cells polyfunctional responses and phenotypic changes in natural killer (NK) cells in adult LTRs presenting with EBV-associated diseases. The CD4/CD8 ratio was significantly decreased in LTRs with EBV DNAemia compared with LTRs without EBV DNAemia and healthy controls (HCs). Stimulation with EBV lytic antigen BZLF1 peptide pools induced significant individual and polyfunctional responses from CD8+ CD69+ T cells. Frequencies of CD8+ CD69+ T cells expressing CD107a were significantly higher in LTRs without EBV DNAemia than in LTRs with DNAemia. Frequencies of CD8+ CD69+ T cells concurrently expressing CD107a, IFN-γ, and TNF-α were significantly greater in LTRs with and without EBV DNAemia than in HCs. Finally, BZLF1 induced significantly higher frequencies of CD8+ CD69+ T cells expressing CD107a and IFN-γ in LTRs without EBV DNAemia when compared with EBNA3B. Frequency of more differentiated CD56dim CD16pos NK cells was significantly decreased in LTRs with EBV DNAemia and PTLD compared with HCs. In conclusion, we noted the presence of significant changes in circulating cellular immune responses to EBV in adult LTRs.

Effect of Antifibrotic Therapy on Survival in Patients With Idiopathic Pulmonary Fibrosis

PURPOSE

Real-world studies have reported reduced mortality in patients with idiopathic pulmonary fibrosis (IPF) treated with antifibrotic therapy; however, the initiation or discontinuation of therapy during these studies may have introduced bias. This study investigated the effect of antifibrotic therapy on mortality and other outcomes in patients with IPF using causal inference methodology.

METHODS

Data from a multicenter US registry of patients with IPF were used to assess the effect of antifibrotic therapy (nintedanib or pirfenidone) on death, death or lung transplant, respiratory-related hospitalization, and acute worsening of IPF (defined as any health care encounter deemed due to acute worsening of IPF). This study used the Gran method, which accounts for differences in patient characteristics and for treatment initiations and discontinuations during follow-up. The analysis cohort was limited to patients who started antifibrotic therapy on or after the day of enrollment or had never taken it.

FINDINGS

Among the 499 patients analyzed, 352 (70.5%) received antifibrotic therapy. Estimated event rates of death at 1 year were 6.6% (95% CI, 6.1-7.1) for treated patients and 10.2% (95% CI, 9.5-10.9) for control patients. There was a numerical reduction in the risk of death (hazard ratio [HR], 0.53; 95% CI, 0.28-1.03; P = 0.060) but numerical increases in risks of respiratory-related hospitalization (HR, 1.88; 95% CI, 0.90-3.92; P = 0.091) and acute worsening of IPF (HR, 1.71; 95% CI, 0.36-8.09; P = 0.496) in treated versus control patients.

IMPLICATIONS

Analyses based on causal inference methodology suggest that patients with IPF who receive antifibrotic therapy have improved survival.

Early posttransplant reductions in club cell secretory protein associate with future risk for chronic allograft dysfunction in lung recipients: results from a multicenter study

BACKGROUND

Chronic lung allograft dysfunction (CLAD) increases morbidity and mortality for lung transplant recipients. Club cell secretory protein (CCSP), produced by airway club cells, is reduced in the bronchoalveolar lavage fluid (BALF) of lung recipients with CLAD. We sought to understand the relationship between BALF CCSP and early posttransplant allograft injury and determine if early posttransplant BALF CCSP reductions indicate later CLAD risk.

METHODS

We quantified CCSP and total protein in 1606 BALF samples collected over the first posttransplant year from 392 adult lung recipients at 5 centers. Generalized estimating equation models were used to examine the correlation of allograft histology or infection events with protein-normalized BALF CCSP. We performed multivariable Cox regression to determine the association between a time-dependent binary indicator of normalized BALF CCSP level below the median in the first posttransplant year and development of probable CLAD.

RESULTS

Normalized BALF CCSP concentrations were 19% to 48% lower among samples corresponding to histological allograft injury as compared with healthy samples. Patients who experienced any occurrence of a normalized BALF CCSP level below the median over the first posttransplant year had a significant increase in probable CLAD risk independent of other factors previously linked to CLAD (adjusted hazard ratio 1.95; p = 0.035).

CONCLUSIONS

We discovered a threshold for reduced BALF CCSP to discriminate future CLAD risk; supporting the utility of BALF CCSP as a tool for early posttransplant risk stratification. Additionally, our finding that low CCSP associates with future CLAD underscores a role for club cell injury in CLAD pathobiology.

Evaluation of Frailty Measures and Short-term Outcomes After Lung Transplantation

BACKGROUND

Frailty, measured as a single construct, is associated variably with poor outcomes before and after lung transplantation. The usefulness of a comprehensive frailty assessment before transplantation is unknown.

RESEARCH QUESTION

How are multiple frailty constructs, including phenotypic and cumulative deficit models, muscle mass, exercise tolerance, and social vulnerabilities, measured before transplantation, associated with short-term outcomes after lung transplantation?

STUDY DESIGN AND METHODS

We conducted a retrospective cohort study of 515 lung recipients who underwent frailty assessments before transplantation, including the short physical performance battery (SPPB), transplant-specific frailty index (FI), 6-min walk distance (6MWD), thoracic sarcopenia, and social vulnerability indexes. We tested the association between frailty measures before transplantation and outcomes after transplantation using logistic regression to model 1-year survival and zero-inflated negative binomial regression to model hospital-free days (HFDs) in the first 90 days after transplantation. Adjustment covariates included age, sex, native lung disease, transplantation type, lung allocation score, BMI, and primary graft dysfunction.

RESULTS

Before transplantation, 51.3% of patients were frail by FI (FI ≥ 0.25) and no patients were frail by SPPB. In multivariate adjusted models that also included FI, SPPB, and 6MWD, greater frailty by FI, but not SPPB, was associated with fewer HFDs (-0.006 per 0.01 unit worsening; 95% CI, -0.01 to -0.002 per 0.01 unit worsening) among discharged patients. Greater SPPB deficits were associated with decreased odds of 1-year survival (OR, 0.51 per 1 unit worsening; 95% CI, 0.28-0.93 per 1 unit worsening). Correlation among frailty measurements overall was poor. No association was found between thoracic sarcopenia, 6MWD, or social vulnerability assessments and short-term outcomes after lung transplantation.

INTERPRETATION

Both phenotypic and cumulative deficit models measured before transplantation are associated with short-term outcomes after lung transplantation. Cumulative deficit measures of frailty may be more relevant in the first 90 days after transplantation, whereas phenotypic frailty may have a stronger association with 1-year survival.

Anti-fibrotic therapy and lung transplant outcomes in patients with idiopathic pulmonary fibrosis

BACKGROUND

It is unclear whether continuing anti-fibrotic therapy until the time of lung transplant increases the risk of complications in patients with idiopathic pulmonary fibrosis.

OBJECTIVES

To investigate whether the time between discontinuation of anti-fibrotic therapy and lung transplant in patients with idiopathic pulmonary fibrosis affects the risk of complications.

METHODS

We assessed intra-operative and post-transplant complications among patients with idiopathic pulmonary fibrosis who underwent lung transplant and had been treated with nintedanib or pirfenidone continuously for ⩾ 90 days at listing. Patients were grouped according to whether they had a shorter (⩽ 5 medication half-lives) or longer (> 5 medication half-lives) time between discontinuation of anti-fibrotic medication and transplant. Five half-lives corresponded to 2 days for nintedanib and 1 day for pirfenidone.

RESULTS

Among patients taking nintedanib (n = 107) or pirfenidone (n = 190), 211 (71.0%) had discontinued anti-fibrotic therapy ⩽ 5 medication half-lives before transplant. Anastomotic and sternal dehiscence occurred only in this group (anastomotic: 11 patients [5.2%], p = 0.031 vs patients with longer time between discontinuation of anti-fibrotic medication and transplant; sternal: 12 patients [5.7%], p = 0.024). No differences were observed in surgical wound dehiscence, length of hospital stay, or survival to discharge between groups with a shorter versus longer time between discontinuation of anti-fibrotic therapy and transplant.

CONCLUSION

Anastomotic and sternal dehiscence only occurred in patients with idiopathic pulmonary fibrosis who discontinued anti-fibrotic therapy < 5 medication half-lives before transplant. The frequency of other intra-operative and post-transplant complications did not appear to differ depending on when anti-fibrotic therapy was discontinued.

REGISTRATION

clinicaltrials.gov NCT04316780: https://clinicaltrials.gov/ct2/show/NCT04316780.

Prognostic implications of and clinical risk factors for acute lung injury and organizing pneumonia after lung transplantation: Data from a multicenter prospective cohort study

We determined prognostic implications of acute lung injury (ALI) and organizing pneumonia (OP), including timing relative to transplantation, in a multicenter lung recipient cohort. We sought to understand clinical risks that contribute to development of ALI/OP. We analyzed prospective, histologic diagnoses of ALI and OP in 4786 lung biopsies from 803 adult lung recipients. Univariable Cox regression was used to evaluate the impact of early (≤90 days) or late (>90 days) posttransplant ALI or OP on risk for chronic lung allograft dysfunction (CLAD) or death/retransplantation. These analyses demonstrated late ALI/OP conferred a two- to threefold increase in the hazards of CLAD or death/retransplantation; there was no association between early ALI/OP and these outcomes. To determine risk factors for late ALI/OP, we used univariable Cox models considering donor/recipient characteristics and posttransplant events as candidate risks. Grade 3 primary graft dysfunction, higher degree of donor/recipient human leukocyte antigen mismatch, bacterial or viral respiratory infection, and an early ALI/OP event were significantly associated with increased late ALI/OP risk. These data from a contemporary, multicenter cohort underscore the prognostic implications of ALI/OP on lung recipient outcomes, clarify the importance of the timing of these events, and identify clinical risks to target for ALI/OP prevention.

Plasma CXCL9 and CXCL10 at allograft injury predict chronic lung allograft dysfunction

Histopathologic lung allograft injuries are putative harbingers for chronic lung allograft dysfunction (CLAD). However, the mechanisms responsible are not well understood. CXCL9 and CXCL10 are potent chemoattractants of mononuclear cells and potential propagators of allograft injury. We hypothesized that these chemokines would be quantifiable in plasma, and would associate with subsequent CLAD development. In this prospective multicenter study, we evaluated 721 plasma samples for CXCL9/CXCL10 levels from 184 participants at the time of transbronchial biopsies during their first-year post-transplantation. We determined the association between plasma chemokines, histopathologic injury, and CLAD risk using Cox proportional hazards models. We also evaluated CXCL9/CXCL10 levels in bronchoalveolar lavage (BAL) fluid and compared plasma to BAL with respect to CLAD risk. Plasma CXCL9/CXCL10 levels were elevated during the injury patterns associated with CLAD, acute rejection, and acute lung injury, with a dose-response relationship between chemokine levels and CLAD risk. Importantly, there were strong interactions between injury and plasma CXCL9/CXCL10, where histopathologic injury associated with CLAD only in the presence of elevated plasma chemokines. We observed similar associations and interactions with BAL CXCL9/CXCL10 levels. Elevated plasma CXCL9/CXCL10 during allograft injury may contribute to CLAD pathogenesis and has potential as a minimally invasive immune monitoring biomarker.

Textbook surgical outcome in lung transplantation: Analysis of a US national registry

Textbook surgical outcome (TO) is a novel composite quality measure in lung transplantation (LTx). Compared to one-year survival metrics, TO may better differentiate center performance, and motivate improvements in care. To understand the feasibility of implementing this metric, we defined TO in LTx using US national data, and evaluated its ability to predict post-transplant outcomes and differentiate center performance. Adult patients who underwent isolated LTx between 2016-2019 were included. TO was defined as freedom from post-transplant length of stay >30 days, 90-day mortality, intubation or extracorporeal membrane oxygenation at 72 hours post-transplant, post-transplant ventilator support lasting ≥5 days, postoperative airway dehiscence, inpatient dialysis, pre-discharge acute rejection, and grade 3 primary graft dysfunction at 72 hours. Recipient and donor characteristics and post-transplant outcomes were compared between patients who achieved and failed TO. Of 8959 lung transplant recipients, 4664 (52.1%) achieved TO. Patient and graft survival were improved among patients who achieved TO (both log-rank p<0.0001). Among 62 centers, adjusted rates of TO ranged from 27.0% to 72.4% reflecting a wide variability in center-level performance. TO defined using national data may represent a novel composite metric to guide quality improvement in LTx across US transplant centers. Summary: In this study we defined textbook outcome (TO) for lung transplantation (LTx) using US national data. We found that achievement of TO was associated with improved post-transplant survival, and wide variability in center-level LTx performance. These findings suggest that TO could be readily implemented to compare quality of care among US LTx centers. This article is protected by copyright. All rights reserved.

Clinical Outcomes of Patients with Combined Idiopathic Pulmonary Fibrosis and Emphysema in the IPF-PRO Registry

Purpose

To assess the impact of concomitant emphysema on outcomes in patients with idiopathic pulmonary fibrosis (IPF).

Methods

The IPF-PRO Registry is a US registry of patients with IPF. The presence of combined pulmonary fibrosis and emphysema (CPFE) at enrollment was determined by investigators’ review of an HRCT scan. Associations between emphysema and clinical outcomes were analyzed using Cox proportional hazards models.

Results

Of 934 patients, 119 (12.7%) had CPFE. Compared with patients with IPF alone, patients with CPFE were older (median 72 vs 70 years); higher proportions were current/former smokers (88.2% vs 63.7%), used oxygen with activity (49.6% vs 31.9%) or at rest (30.8% vs 18.4%), had congestive heart failure (13.6% vs 4.8%) and had prior respiratory hospitalization (25.0% vs 16.7%); they had higher FVC (median 71.8 vs 69.4% predicted) and lower DLco (median 35.3 vs 43.6% predicted). In patients with CPFE and IPF alone, respectively, at 1 year, rates of death or lung transplant were 17.5% (95% CI: 11.7, 25.8) and 11.2% (9.2, 13.6) and rates of hospitalization were 21.6% (14.6, 29.6) and 20.6% (17.9, 23.5). There were no significant associations between emphysema and any outcome after adjustment for baseline variables. No baseline variable predicted outcomes better in IPF alone than in CPFE.

Conclusion

Approximately 13% of patients in the IPF-PRO Registry had CPFE. Physiologic characteristics and comorbidities of patients with CPFE differed from those of patients with IPF alone, but the presence of emphysema did not drive outcomes after adjustment for baseline covariates.

Trial registration

ClinicalTrials.gov, NCT01915511; registered August 5, 2013.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00408-021-00506-x.

Cytomegalovirus prevention in thoracic organ transplantation: A single-center evaluation of letermovir prophylaxis

BACKGROUND

Cytomegalovirus (CMV) infection is common following thoracic organ transplantation and causes substantial morbidity and mortality. Letermovir is a novel antiviral agent used off-label in this population for CMV prevention. Our goal was to understand patterns of letermovir use and effectiveness when applied for CMV prophylaxis after thoracic transplantation.

METHODS

We retrospectively evaluated letermovir use among thoracic transplant recipients at an academic transplant center who initiated letermovir from January 2018 to October2019 for CMV prophylaxis. We analyzed indication, timing, and duration of prophylaxis; tolerability; and occurrence of breakthrough CMV DNAemia and disease.

RESULTS

Forty-two episodes of letermovir prophylaxis occurred in 41 patients, including 37 lung and 4 heart transplant recipients. Primary prophylaxis (26/42, 61.9%) was utilized mainly due to myelosuppression (25/26, 96.2%) and was initiated a median of 315 days post-transplant (interquartile range [IQR] 125-1139 days). Sixteen episodes of secondary prophylaxis (16/42, 38.1%) were initiated a median of 695 days post-transplant (IQR 537-1156 days) due to myelosuppression (10/16, 62.5%) or prior CMV resistance (6/16, 37.5%). Median duration of letermovir prophylaxis was 282 days (IQR 131-433 days). Adverse effects required letermovir cessation in 5/42 (11.9%) episodes. Only one episode (2.4%) was complicated by clinically significant breakthrough CMV infection. Transient low-level CMV DNAemia (<450 IU/ml) occurred in 15 episodes (35.7%) but did not require letermovir cessation.

CONCLUSIONS

Letermovir was well tolerated and effective during extended prophylactic courses with only one case of breakthrough CMV infection in this cohort of thoracic transplant recipients. Further prospective trials of letermovir prophylaxis in this population are warranted.

Correlation between BAL CXCR3 chemokines and lung allograft histopathologies: A multicenter study

The histopathologic diagnosis of acute allograft injury is prognostically important in lung transplantation with evidence demonstrating a strong and consistent association between acute rejection (AR), acute lung injury (ALI), and the subsequent development of chronic lung allograft dysfunction (CLAD). The pathogenesis of these allograft injuries, however, remains poorly understood. CXCL9 and CXCL10 are CXC chemokines induced by interferon-γ and act as potent chemoattractants of mononuclear cells. We hypothesized that these chemokines are involved in the mononuclear cell recruitment associated with AR and ALI. We further hypothesized that the increased activity of these chemokines could be quantified as increased levels in the bronchoalveolar lavage fluid. In this prospective multicenter study, we evaluate the incidence of histopathologic allograft injury development during the first-year post-transplant and measure bronchoalveolar CXCL9 and CXCL10 levels at the time of the biopsy. In multivariable models, CXCL9 levels were 1.7-fold and 2.1-fold higher during AR and ALI compared with "normal" biopsies without histopathology. Similarly, CXCL10 levels were 1.6-fold and 2.2-fold higher during these histopathologies, respectively. These findings support the association of CXCL9 and CXCL10 with episodes of AR and ALI and provide potential insight into the pathogenesis of these deleterious events.

Hospitalizations in patients with idiopathic pulmonary fibrosis

Background

Hospitalizations are common among patients with idiopathic pulmonary fibrosis (IPF). We investigated the impact of hospitalizations on outcomes in patients with IPF.

Methods

The IPF-PRO Registry is an observational US registry that enrolled patients with IPF that was diagnosed or confirmed at the enrolling center in the previous 6 months. Associations between patient characteristics and hospitalization, and between hospitalization and mortality, were analyzed using Cox regression models.

Results

A total of 1002 patients with IPF were enrolled into the IPF-PRO Registry. Over a median follow-up time of 23.7 months (maximum: 67.0 months), 568 patients (56.7%) had at least one hospitalization. Of these patients, 319 (56.2%) had at least one respiratory-related hospitalization and 120 (21.1%) had at least one hospitalization with ventilatory support. Younger age (HR 0.68 [95% CI 0.55, 0.84] per 5-year increase for patients < 62 years), lower BMI (0.96 [0.93, 0.98] per 1-point increase), lower FVC % predicted (0.90 [0.83, 0.97] per 10% increase), oxygen use at rest (2.85 [2.18, 3.72]) and history of pulmonary hypertension (2.02 [1.37, 2.96]) at enrollment were associated with an increased risk of respiratory-related hospitalization during follow-up. In a multivariable model, there was an eightfold increase in the risk of mortality during hospitalization or within 90 days of discharge compared with outside of this period. The risk of mortality associated with a respiratory hospitalization or a hospitalization with ventilatory support was even greater.

Conclusions

Data from the IPF-PRO Registry demonstrate that hospitalizations are common among patients with IPF. The risk of mortality during hospitalization or within 90 days of discharge was high, particularly among patients who were hospitalized for a respiratory cause or received ventilatory support.

Trial registration ClinicalTrials.gov, NCT01915511. Registered 5 August 2013, https://clinicaltrials.gov/ct2/show/NCT01915511

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01851-4.

Sleep quality, depressive symptoms, and transplant outcomes: Follow-up analyses from the ADAPT prospective pilot study

BACKGROUND

Previous studies suggested that depressive symptoms and sleep quality may be important for long-term clinical outcomes following cardiothoracic transplant. Few studies, however, have systematically examined objective markers of these behavioral factors among ambulatory transplant recipients, or their association with clinical outcomes.

METHODS

We examined sleep quality and depressive symptoms with subsequent clinical outcomes (hospitalizations and death) in a sample of 66 lung or heart transplant recipients using a single-center, prospective cohort study. Recipients were assessed at approximately 6 months post-transplant and completed one week of actigraphy assessment to examine sleep quality and self-report measures of mood (Centers for Epidemiologic Studies of Depression [CESD]). Recipients were followed for clinical outcomes.

RESULTS

At 6-months following transplantation, recipients spent the majority of daytime activity at a sedentary level (61% of daily activity [SD = 10]) and elevated depressive symptoms were common (subclinical = 17%, mild = 12%, or moderate = 8%). Over a median follow-up of 4.5 years (IQR = 0.9, 5.1), 51 participants (77%) had at least one unplanned hospitalization and 11 (17%) participants died. In addition, sleep efficiency measurements suggested that a subset of participants exhibited suboptimal sleep (mean efficiency = 87% [SD = 7]). Poorer sleep quality, indexed by lower sleep efficiency and greater sleep fragmentation, was associated with greater depressive symptoms (r's = 0.37-0.50, P < .01). Better sleep quality at 6-months (HR = 0.75 [0.60, 0.95], P = .015), including sleep efficiency (HR = 0.74 [0.56, 0.99], P = .041) and sleep fragmentation (HR = 0.71 [0.53, 0.95], P = .020) were associated with lower risk of hospitalization or death. Compared with individuals without elevated depressive symptoms or sleep difficulties, individuals with either factor (HR = 1.72 [1.05, 2.81], P = .031) or both factors (HR = 2.37 [1.35, 4.18], P = .003) exhibited greater risk of clinical events in adjusted analyses.

CONCLUSIONS

Sleep quality is associated with depressive symptoms among cardiothoracic transplant recipients and enhances the prognostic association between biobehavioral risk factors and clinical outcomes.

ISHLT consensus document on lung transplantation in patients with connective tissue disease: Part I: Epidemiology, assessment of extrapulmonary conditions, candidate evaluation, selection criteria, and pathology statements

Patients with connective tissue disease (CTD) and advanced lung disease are often considered suboptimal candidates for lung transplantation (LTx) due to their underlying medical complexity and potential surgical risk. There is substantial variability across LTx centers regarding the evaluation and listing of these patients. The International Society for Heart and Lung Transplantation-supported consensus document on lung transplantation in patients with CTD standardization aims to clarify definitions of each disease state included under the term CTD, to describe the extrapulmonary manifestations of each disease requiring consideration before transplantation, and to outline the absolute contraindications to transplantation allowing risk stratification during the evaluation and selection of candidates for LTx.

Time to diagnosis of idiopathic pulmonary fibrosis in the IPF-PRO Registry

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with high mortality. Patient characteristics associated with diagnostic delays are not well described.

METHODS

Subjects who had not been diagnosed with IPF prior to referral and received a new diagnosis of IPF at an enrolling centre for the IPF-PRO (Idiopathic Pulmonary Fibrosis Prospective Outcomes) Registry were characterised as having a longer (>1 year) or shorter (≤1 year) time from symptom onset to diagnosis and from first imaging evidence of fibrosis to diagnosis. Patient characteristics, evaluations and time to death or lung transplant were compared between these cohorts.

RESULTS

Among 347 patients with a symptom onset date, 49% were diagnosed with IPF >1 year after symptom onset. These patients were slightly younger and had more cardiac comorbidities than patients diagnosed ≤1 year after symptom onset. Among 454 patients with a date for imaging evidence of fibrosis, 78% were diagnosed with IPF ≤1 year later. A greater proportion of patients with >1 year versus ≤1 year from imaging evidence of fibrosis to diagnosis had cardiac comorbidities and gastro-oesophageal reflux. There was no significant difference in time to death or lung transplant between groups by time to diagnosis.

CONCLUSIONS

The time from symptom onset to diagnosis remains over 1 year in approximately half of the patients with IPF, but once imaging evidence is obtained, most of the patients are diagnosed within a year. Cardiac conditions and gastro-oesophageal disorders were more commonly reported in patients with a longer time to diagnosis.

Frailty and aging-associated syndromes in lung transplant candidates and recipients

Many lung transplant candidates and recipients are older and frailer compared to previous eras. Older patients are at increased risk for pre- and posttransplant mortality, but this risk is not explained by numerical age alone. This manuscript represents the product of the American Society of Transplantation (AST) conference on frailty. Experts in the field reviewed the latest published research on assessment of elderly and frail lung transplant candidates. Physical frailty, often defined as slowness, weakness, low physical activity, shrinking, and exhaustion, and frailty evaluation is an important tool for evaluation of age-associated dysfunction. Another approach is assessment by cumulative deficits, and both types of frailty are common in lung transplant candidates. Frailty is associated with death or delisting before transplant, and may be associated with posttransplant mortality. Sarcopenia, cognitive dysfunction, depression, and nutrition are other important components for patient evaluation. Aging-associated inflammation, telomere dysfunction, and adaptive immune system senescence may also contribute to frailty. Developing tools for frailty assessment and interventions holds promise for improving patient outcomes before and after lung transplantation.

Lung Transplantation and the Era of the Sensitized Patient

Long term outcomes in lung transplant are limited by the development of chronic lung allograft dysfunction (CLAD). Within the past several decades, antibody-mediated rejection (AMR) has been recognized as a risk factor for CLAD. The presence of HLA antibodies in lung transplant candidates, "sensitized patients" may predispose patients to AMR, CLAD, and higher mortality after transplant. This review will discuss issues surrounding the sensitized patient, including mechanisms of sensitization, implications within lung transplant, and management strategies.

Effect of Antimicrobial Therapy on Respiratory Hospitalization or Death in Adults With Idiopathic Pulmonary Fibrosis: The CleanUP-IPF Randomized Clinical Trial

IMPORTANCE

Alteration in lung microbes is associated with disease progression in idiopathic pulmonary fibrosis.

OBJECTIVE

To assess the effect of antimicrobial therapy on clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS

Pragmatic, randomized, unblinded clinical trial conducted across 35 US sites. A total of 513 patients older than 40 years were randomized from August 2017 to June 2019 (final follow-up was January 2020).

INTERVENTIONS

Patients were randomized in a 1:1 allocation ratio to receive antimicrobials (n = 254) or usual care alone (n = 259). Antimicrobials included co-trimoxazole (trimethoprim 160 mg/sulfamethoxazole 800 mg twice daily plus folic acid 5 mg daily, n = 128) or doxycycline (100 mg once daily if body weight <50 kg or 100 mg twice daily if ≥50 kg, n = 126). No placebo was administered in the usual care alone group.

MAIN OUTCOMES AND MEASURES

The primary end point was time to first nonelective respiratory hospitalization or all-cause mortality.

RESULTS

Among the 513 patients who were randomized (mean age, 71 years; 23.6% women), all (100%) were included in the analysis. The study was terminated for futility on December 18, 2019. After a mean follow-up time of 13.1 months (median, 12.7 months), a total of 108 primary end point events occurred: 52 events (20.4 events per 100 patient-years [95% CI, 14.8-25.9]) in the usual care plus antimicrobial therapy group and 56 events (18.4 events per 100 patient-years [95% CI, 13.2-23.6]) in the usual care group, with no significant difference between groups (adjusted HR, 1.04 [95% CI, 0.71-1.53; P = .83]. There was no statistically significant interaction between the effect of the prespecified antimicrobial agent (co-trimoxazole vs doxycycline) on the primary end point (adjusted HR, 1.15 [95% CI 0.68-1.95] in the co-trimoxazole group vs 0.82 [95% CI, 0.46-1.47] in the doxycycline group; P = .66). Serious adverse events occurring at 5% or greater among those treated with usual care plus antimicrobials vs usual care alone included respiratory events (16.5% vs 10.0%) and infections (2.8% vs 6.6%); adverse events of special interest included diarrhea (10.2% vs 3.1%) and rash (6.7% vs 0%).

CONCLUSIONS AND RELEVANCE

Among adults with idiopathic pulmonary fibrosis, the addition of co-trimoxazole or doxycycline to usual care, compared with usual care alone, did not significantly improve time to nonelective respiratory hospitalization or death. These findings do not support treatment with these antibiotics for the underlying disease.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02759120.

Risk of primary graft dysfunction following lung transplantation in selected adults with connective tissue disease-associated interstitial lung disease

BACKGROUND

Previous studies have reported similarities in long-term outcomes following lung transplantation for connective tissue disease-associated interstitial lung disease (CTD-ILD) and idiopathic pulmonary fibrosis (IPF). However, it is unknown whether CTD-ILD patients are at increased risk of primary graft dysfunction (PGD), delays in extubation, or longer index hospitalizations following transplant compared to IPF patients.

METHODS

We performed a multicenter retrospective cohort study of CTD-ILD and IPF patients enrolled in the Lung Transplant Outcomes Group registry who underwent lung transplantation between 2012 and 2018. We utilized mixed effects logistic regression and stratified Cox proportional hazards regression to determine whether CTD-ILD was independently associated with increased risk for grade 3 PGD or delays in post-transplant extubation and hospital discharge compared to IPF.

RESULTS

A total of 32.7% (33/101) of patients with CTD-ILD and 28.9% (145/501) of patients with IPF developed grade 3 PGD 48-72 hours after transplant. There were no significant differences in odds of grade 3 PGD among patients with CTD-ILD compared to those with IPF (adjusted OR 1.12, 95% CI 0.64-1.97, p = 0.69), nor was CTD-ILD independently associated with a longer post-transplant time to extubation (adjusted HR for first extubation 0.87, 95% CI 0.66-1.13, p = 0.30). However, CTD-ILD was independently associated with a longer post-transplant hospital length of stay (median 23 days [IQR 14-35 days] vs17 days [IQR 12-28 days], adjusted HR for hospital discharge 0.68, 95% CI 0.51-0.90, p = 0.008).

CONCLUSION

Patients with CTD-ILD experienced significantly longer postoperative hospitalizations compared to IPF patients without an increased risk of grade 3 PGD.

Hyperbaric oxygen therapy to prevent central airway stenosis after lung transplantation

BACKGROUND

Central airway stenosis (CAS) is a severe airway complication after lung transplantation associated with bronchial ischemia and necrosis. We sought to determine whether hyperbaric oxygen therapy (HBOT), an established treatment for tissue ischemia, attenuates post-transplant bronchial injury.

METHODS

We performed a randomized, controlled trial comparing usual care with HBOT (2 atm absolute for 2 hours × 20 sessions) in subjects with extensive airway necrosis 4 weeks after transplantation. Endobronchial biopsies were collected at 4, 7, and 10 weeks after transplantation for a quantitative polymerase chain reaction. Coprimary outcomes were incidence of airway stenting and acute cellular rejection (ACR) at 1 year.

RESULTS

The trial was stopped after enrolling 20 subjects (n = 10 per group) after a pre-planned interim analysis showed no difference between usual care and HBOT groups in stenting (both 40%), ACR (70% and 40%, respectively), or CAS (40% and 60%, respectively). Time to first stent placement (median [interquartile range]) was significantly shorter in the HBOT group (150 [73-150] vs 186 [167-206] days, p < 0.05). HIF gene expression was significantly increased in donor tissues at 4, 7, and 10 weeks after transplantation but was not altered by HBOT. Subjects who developed CAS or required stenting had significantly higher HMOX1 and VEGFA expression at 4 weeks (both p < 0.05). Subjects who developed ACR had significant FLT1, TIE2, and KDR expression at 4 weeks (all p < 0.05).

CONCLUSIONS

Incidence of CAS is high after severe, established airway necrosis after transplantation. HBOT does not reduce CAS severity or stenting. Elevated HMOX1 and VEGFA expressions appear to associate with airway complications.

Depression, Immunosuppressant Levels, and Clinical Outcomes in Postlung Transplant Recipients

OBJECTIVE

Posttransplant depression has been linked to increased risk for adverse outcomes in lung transplant patients. Maintaining target serum immunosuppressant levels is also essential for optimal lung transplant clinical outcome and may be a crucial predictor of outcomes. Because depression could affect medication nonadherence, resulting in out-of-range immunosuppressant levels, we examined the relationship between posttransplant depression, immunosuppressant medication trough level variability, indexed by out-of-range values on clinical outcomes and coefficient of variability, and clinical outcomes.

METHOD

A consecutive series of 236 lung transplant recipients completed the Center for Epidemiological Studies-Depression two-month posttransplant. Immunosuppressant trough levels (i.e., tacrolimus or cyclosporine) within the range of individualized immunosuppressant targets were obtained at three-, six-, nine-month follow-up clinic visits. Clinical outcomes including hospitalizations and mortality were obtained from medical records.

RESULTS

Fourteen percent of patients were classified as depressed (Center for Epidemiological Studies-Depression ≥16), 144 (61%) of patients had at least 25% out-of-range immunosuppressant values, and the average coefficient of variability was 36%. Over a median of 2.6 years (interquartile range = 1.2), 32 participants died (14%) and 144 (61%) had at least one unplanned, transplant-related hospitalization. Both depression (hazard ratio = 1.45 (1.19, 1.76), p < . 01) and immunosuppressant variation (immunosuppressant out-of-range: hazard ratio = 1.41 (1.10, 1.81), p < .01) independently predicted more frequent hospitalizations and higher mortality.

CONCLUSIONS

Early posttransplant depression was associated with significantly worse clinical outcomes. While immunosuppressant level variability is also related to adverse outcomes, such variability does not account for increased risk observed with depression.

Risk Factors for Acute Rejection in the First Year after Lung Transplant. A Multicenter Study

Rationale: Acute rejection, manifesting as lymphocytic inflammation in a perivascular (acute perivascular rejection [AR]) or peribronchiolar (lymphocytic bronchiolitis [LB]) distribution, is common in lung transplant recipients and increases the risk for chronic graft dysfunction.Objectives: To evaluate clinical factors associated with biopsy-proven acute rejection during the first post-transplant year in a present-day, five-center lung transplant cohort.Methods: We analyzed prospective diagnoses of AR and LB from over 2,000 lung biopsies in 400 newly transplanted adult lung recipients. Because LB without simultaneous AR was rare, our analyses focused on risk factors for AR. Multivariable Cox proportional hazards models were used to assess donor and recipient factors associated with the time to the first AR occurrence.Measurements and Main Results: During the first post-transplant year, 53.3% of patients experienced at least one AR episode. Multivariable proportional hazards analyses accounting for enrolling center effects identified four or more HLA mismatches (hazard ratio [HR], 2.06; P ≤ 0.01) as associated with increased AR hazards, whereas bilateral transplantation (HR, 0.57; P ≤ 0.01) was associated with protection from AR. In addition, Wilcoxon rank-sum analyses demonstrated bilateral (vs. single) lung recipients, and those with fewer than four (vs. more than four) HLA mismatches demonstrated reduced AR frequency and/or severity during the first post-transplant year.Conclusions: We found a high incidence of AR in a contemporary multicenter lung transplant cohort undergoing consistent biopsy sampling. Although not previously recognized, the finding of reduced AR in bilateral lung recipients is intriguing, warranting replication and mechanistic exploration.

Incidence and outcome of post-transplant lymphoproliferative disorders in lung transplant patients: Analysis of ISHLT Registry

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a life-threatening complication following lung transplant. We studied incidence and risk factors for PTLD in adult lung transplant recipients (LTRs) using the International Society for Heart and Lung Transplantation Registry.

METHODS

The International Society for Heart and Lung Transplantation Registry was used to identify adult, first-time, single and bilateral LTRs with at least 1 year of follow-up between 2006 and 2016. Kaplan-Meier method was used to describe the timing and distribution of PTLD. Univariable and multivariable Cox proportional hazards regression models were used to examine clinical characteristics associated with PTLD.

RESULTS

Of 19,309 LTRs in the analysis cohort, we identified 454 cases of PTLD. Cumulative incidence of PTLD was 1.1% (95% CI = 1.0%-1.3%) at 1 year and 4.1% (95% CI = 3.6%-4.6%) at 10 years. Of the PTLD cases, 47.4% occurred within the first year following lung transplantation. In the multivariable model, independent risk factors for PTLD included age, Epstein-Barr virus serostatus, restrictive lung diseases, and induction. Risk of PTLD during the first year after transplant increased with increasing age in patients between 45 and 62 years at time of transplantation; the inverse was true for ages <45 years or >62 years. Finally, receiving a donor organ with human leukocyte antigen types A1 and A24 was associated with an increased risk of PTLD, whereas the recipient human leukocyte antigen type DR11 was associated with a decreased risk.

CONCLUSIONS

Our study indicates that PTLD is a relatively rare complication among adult LTRs. We identified clinical characteristics that are associated with an increased risk of PTLD.

Skeletal muscle adiposity and outcomes in candidates for lung transplantation: a lung transplant body composition cohort study

CT measurement of body composition may improve lung transplant candidate selection. We assessed whether skeletal muscle adipose deposition on abdominal and thigh CT scans was associated with 6 min walk distance (6MWD) and wait-list survival in lung transplant candidates. Each ½-SD decrease in abdominal muscle attenuation (indicating greater lipid content) was associated with 14 m decrease in 6MWD (95% CI -20 to -8) and 20% increased risk of death or delisting (95% CI 10% to 40%). Each ½-standard deviation decrease in thigh muscle attenuation was associated with 15 m decrease in 6MWD (95% CI -21 to -10). CT imaging may improve candidate risk stratification.

Highlights from the clinical trials in organ transplantation (CTOT)-20 and CTOT-22 Consortium studies in lung transplant

Long-term survival after lung transplant lags behind that of other commonly transplanted organs, reflecting the current incomplete understanding of the mechanisms involved in the development of posttransplant lung injury, rejection, infection, and chronic allograft dysfunction. To address this unmet need, 2 ongoing National Institute of Allergy and Infectious Disease funded studies through the Clinical Trials in Organ Transplant Consortium (CTOT) CTOT-20 and CTOT-22 were dedicated to understanding the clinical factors and biological mechanisms that drive chronic lung allograft dysfunction and those that maintain cytomegalovirus polyfunctional protective immunity. The CTOT-20 and CTOT-22 studies enrolled 800 lung transplant recipients at 5 North American centers over 3 years. Given the number and complexity of subjects included, CTOT-20 and CTOT-22 utilized innovative data transfers and capitalized on patient-entered data collection to minimize site manual data entry. The data were coupled with an extensive biosample collection strategy that included DNA, RNA, plasma, serum, bronchoalveolar lavage fluid, and bronchoalveolar lavage cell pellet. This Special Article describes the CTOT-20 and CTOT-22 protocols, data and biosample strategy, initial results, and lessons learned through study execution.

Bronchoalveolar bile acid and inflammatory markers to identify high-risk lung transplant recipients with reflux and microaspiration

BACKGROUND

Gastroesophageal reflux disease (GERD) is a risk factor for chronic lung allograft dysfunction. Bile acids-putative markers of gastric microaspiration-and inflammatory proteins in the bronchoalveolar lavage (BAL) have been associated with chronic lung allograft dysfunction, but their relationship with GERD remains unclear. Although GERD is thought to drive chronic microaspiration, the selection of patients for anti-reflux surgery lacks precision. This multicenter study aimed to test the association of BAL bile acids with GERD, lung inflammation, allograft function, and anti-reflux surgery.

METHODS

We analyzed BAL obtained during the first post-transplant year from a retrospective cohort of patients with and without GERD, as well as BAL obtained before and after Nissen fundoplication anti-reflux surgery from a separate cohort. Levels of taurocholic acid (TCA), glycocholic acid, and cholic acid were measured using mass spectrometry. Protein markers of inflammation and injury were measured using multiplex assay and enzyme-linked immunosorbent assay.

RESULTS

At 3 months after transplantation, TCA, IL-1β, IL-12p70, and CCL5 were higher in the BAL of patients with GERD than in that of no-GERD controls. Elevated TCA and glycocholic acid were associated with concurrent acute lung allograft dysfunction and inflammatory proteins. The BAL obtained after anti-reflux surgery contained reduced TCA and inflammatory proteins compared with that obtained before anti-reflux surgery.

CONCLUSIONS

Targeted monitoring of TCA and selected inflammatory proteins may be useful in lung transplant recipients with suspected reflux and microaspiration to support diagnosis and guide therapy. Patients with elevated biomarker levels may benefit most from anti-reflux surgery to reduce microaspiration and allograft inflammation.

Perspectives on donor lung allocation from both sides of the Atlantic: The United States

Donor lung allocation in the United States focuses on decreasing waitlist mortality and improving recipient outcomes. The implementation of allocation policy to match deceased donor lungs to waitlisted patients occurs through a unique partnership between government and private organizations, namely the Organ Procurement and Transplantation Network under the Department of Health and Human Services and the United Network for Organ Sharing. In 2005, the donor lung allocation algorithm shifted toward the prioritization of medical urgency of waitlisted patients instead of time accrued on the waitlist. This led to the Lung Allocation Score, which weighs over a dozen clinical variables to predict a 1-year estimate of survival benefit, and is used to prioritize waitlisted patients. In 2017, the use of local allocation boundaries was eliminated in favor of a 250 nautical mile radius from the donor hospital as the first unit of distance used in allocation. The next upcoming iteration of donor allocation policy is expected to use a continuous distribution algorithm where all geographic boundaries are eliminated. There are additional opportunities to improve donor lung allocation, such as for patients with high antibody titers with access to a limited number of donors.

Quantitative Evidence for Revising the Definition of Primary Graft Dysfunction after Lung Transplant

RATIONALE

Primary graft dysfunction (PGD) is a form of acute lung injury that occurs after lung transplantation. The definition of PGD was standardized in 2005. Since that time, clinical practice has evolved, and this definition is increasingly used as a primary endpoint for clinical trials; therefore, validation is warranted.

OBJECTIVES

We sought to determine whether refinements to the 2005 consensus definition could further improve construct validity.

METHODS

Data from the Lung Transplant Outcomes Group multicenter cohort were used to compare variations on the PGD definition, including alternate oxygenation thresholds, inclusion of additional severity groups, and effects of procedure type and mechanical ventilation. Convergent and divergent validity were compared for mortality prediction and concurrent lung injury biomarker discrimination.

MEASUREMENTS AND MAIN RESULTS

A total of 1,179 subjects from 10 centers were enrolled from 2007 to 2012. Median length of follow-up was 4 years (interquartile range = 2.4-5.9). No mortality differences were noted between no PGD (grade 0) and mild PGD (grade 1). Significantly better mortality discrimination was evident for all definitions using later time points (48, 72, or 48-72 hours; P < 0.001). Biomarker divergent discrimination was superior when collapsing grades 0 and 1. Additional severity grades, use of mechanical ventilation, and transplant procedure type had minimal or no effect on mortality or biomarker discrimination.

CONCLUSIONS

The PGD consensus definition can be simplified by combining lower PGD grades. Construct validity of grading was present regardless of transplant procedure type or use of mechanical ventilation. Additional severity categories had minimal impact on mortality or biomarker discrimination.

Decreased Antibiotic Utilization After Sinus Surgery in Cystic Fibrosis Patients With Lung Transplantation

Background

Patients with cystic fibrosis (CF) who have undergone lung transplantation frequently require hospitalizations and antibiotic treatments for respiratory tract infections. Although endoscopic sinus surgery (ESS) improves sinonasal quality of life in CF patients, it is unclear if ESS offers additional benefit in terms of antibiotics for pulmonary infection, hospitalization, and pulmonary function.

Objective

To determine whether ESS impacts antibiotic use or hospitalizations for pulmonary indications or pulmonary function in CF patients after lung transplantation.

Methods

This is a single-institution retrospective study of all patients who underwent lung transplantation for CF from 2005 to 2017. Patients who underwent ESS at least 1 year after transplant were included. Paired bivariate analyses were performed to determine whether there was a difference in the frequency and length of hospitalizations for pulmonary indications, number of antibiotic courses (intravenous and oral) for pulmonary exacerbations, and forced expiratory volume in 1 second (FEV1) slope in the 6 months before versus after ESS. Perioperative antibiotics and hospitalizations were not included in the analyses. Least squares regression was utilized to analyze FEV1 trends.

Results

A total of 20 patients underwent 36 ESS during the study period. There was significantly higher antibiotic utilization in the 6 months before ESS (0.89 ± 1.03) compared to the 6 months after ESS (0.33 ± 0.53) ( P = .002). The frequency and length of hospitalizations, FEV1 slope, and FEV1 trend before and after ESS were not significantly different.

Conclusion

Our results suggest that ESS is associated with a reduction in the frequency of antibiotic utilization for respiratory tract infections in lung transplant recipients with CF. A prospective study is needed to investigate these relationships further.

National Heart, Lung, and Blood Institute and American Association for Thoracic Surgery Workshop Report: Identifying collaborative clinical research priorities in lung transplantation

This report summarizes the discussion and recommendations from the June 2017 NHLBI-AATS Workshop on Identifying Collaborative Clinical Research Priorities in Lung Transplantation.

Frailty in the End-Stage Lung Disease or Heart Failure Patient: Implications for the Perioperative Transplant Clinician

The syndrome of frailty for patients undergoing heart or lung transplantation has been a recent focus for perioperative clinicians because of its association with postoperative complications and poor outcomes. Patients with end-stage cardiac or pulmonary failure may be under consideration for heart or lung transplantation along with bridging therapies such as ventricular assist device implantation or venovenous extracorporeal membrane oxygenation, respectively. Early identification of frail patients in an attempt to modify the risk of postoperative morbidity and mortality has become an important area of study over the last decade. Many quantification tools and risk prediction models for frailty have been developed but have not been evaluated extensively or standardized in the cardiothoracic transplant candidate population. Heightened awareness of frailty, coupled with a better understanding of distinct cellular mechanisms and biomarkers apart from end-stage organ disease, may play an important role in potentially reversing frailty related to organ failure. Furthermore, the clinical management of these critically ill patients may be enhanced by waitlist and postoperative physical rehabilitation and nutritional optimization.

Pre-transplant weight loss and clinical outcomes after lung transplantation

BACKGROUND

Patients with greater adiposity before lung transplantation are at an increased risk for worse post-transplant outcomes. Few studies have addressed whether pre-transplant weight loss mitigates this risk. In this study we examined the association between pre-transplant weight loss and post-transplant clinical outcomes.

METHODS

We conducted a retrospective cohort study of patients who received a lung transplant at the Duke University Hospital from May 1, 2005 to April 30, 2015. The sample included adult transplant recipients with restrictive, obstructive, and vascular diseases. Cox proportional hazards models were used to examine mortality and chronic lung allograft dysfunction (CLAD)-free survival, and negative binomial regression analyses were used to examine length of stay (LOS). Weight loss was assessed from change in body mass index (BMI).

RESULTS

The cohort consisted of 810 patients. Initially, 403 (50%) were overweight and 109 (13%) were obese by BMI criteria. Greater pre-transplant weight loss was associated with dose-response improvements in survival (hazard ratio [HR] 0.83 [0.72 to 0.97], p = 0.018), with modest (0% to 3%, HR 0.91), moderate (7% to 10%, HR 0.83), and high (>15%, HR 0.71) levels of weight loss conferring longer survival, independent of initial weight (p = 0.533 for interaction). Weight loss was also associated with improved CLAD-free survival (HR 0.84 [0.71 to 0.99], p = 0.034) and shorter LOS (b = ‒0.17, p < 0.001).

CONCLUSIONS

Weight loss before transplantation was associated with improved short- and long-term clinical outcomes, independent of initial weight. Survival improved proportionally to percentage of weight lost. The mechanisms by which weight loss improve clinical outcomes warrant further exploration.

Depression, social support, and clinical outcomes following lung transplantation: a single-center cohort study

Depressive symptoms are common among lung transplant candidates and have been associated with poorer clinical outcomes in some studies. Previous studies have been plagued by methodologic problems, including small sample sizes, few clinical events, and uncontrolled confounders, particularly perioperative complications. In addition, few studies have examined social support as a potential protective factor. We therefore examined the association between pretransplant depressive symptoms, social support, and mortality in a large sample of lung transplant recipients. As a secondary aim, we also examined the associations between psychosocial factors, perioperative outcomes [indexed by hospital length of stay (LOS)], and mortality. We hypothesized that depression would be associated with longer LOS and that the association between depression, social support, and mortality would be moderated by LOS. Participants included lung transplant recipients, transplanted at Duke University Medical Center from January 2009 to December 2014. Depressive symptoms were evaluated using the Beck Depression Inventory (BDI-II) and social support using the Perceived Social Support Scale (PSSS). Medical risk factors included forced vital capacity (FVC), partial pressure of carbon dioxide (PCO₂ ), donor age, acute rejection, and transplant type. Functional status was assessed using six-minute walk distance (6MWD). We also controlled for demographic factors, including age, gender, and native disease. Transplant hospitalization LOS was examined as a marker of perioperative clinical outcomes. Participants included 273 lung recipients (174 restrictive, 67 obstructive, 26 cystic fibrosis, and six "other"). Pretransplant depressive symptoms were common, with 56 participants (21%) exhibiting clinically elevated levels (BDI-II ≥ 14). Greater depressive symptoms were associated with longer LOS [adjusted b = 0.20 (2 days per 7-point higher BDI-II score), P < 0.01]. LOS moderated the associations between depressive symptoms (P = 0.019), social support (P < 0.001), and mortality, such that greater depressive symptoms and lower social support were associated with greater mortality only among individuals with longer LOS. For individuals with LOS ≥ 1 month, clinically elevated depressive symptoms (BDI-II ≥ 14) were associated with a threefold increased risk of mortality (HR = 2.97). Greater pretransplant depressive symptoms and lower social support may be associated with greater mortality among a subset of individuals with worse perioperative outcomes.

Correlation between sinus and lung cultures in lung transplant patients with cystic fibrosis

BACKGROUND

Lung transplantation has revolutionized the treatment of end-stage pulmonary disease due to cystic fibrosis. However, infection of the transplanted lungs can lead to serious complications, including graft failure and death. Although many of these patients have concurrent sinusitis, it is unclear whether bacteria from the sinuses can infect the allograft.

METHODS

This is a single-institution retrospective study of all patients who underwent lung transplantation for cystic fibrosis from 2005 to 2015 at Duke University Hospital. Pre- and posttransplant nasal and pulmonary cultures obtained via nasal endoscopy and bronchoalveolar lavage (BAL), respectively, were analyzed.

RESULTS

A total of 141 patients underwent 144 lung transplants. Sinus cultures were available for 76 patients (12 pretransplant, 42 posttransplant, 22 both pre- and posttransplant). Pretransplant BAL cultures were available for 139 patients, and posttransplant BAL cultures were available for all patients. Pseudomonas aeruginosa (PsA) and methicillin-resistant Staphylococcus aureus (MRSA) were the most common organisms cultured. There was a significant correlation between pretransplant sinus and posttransplant BAL cultures for PsA (p = 0.003), MRSA (p = 0.013), and Burkholderia cepacia (p = 0.001).

CONCLUSION

There was a high correlation between pretransplant sinus cultures and posttransplant BAL cultures for PsA, MRSA, and Burkholderia sp. This suggests that the paranasal sinuses may act as a reservoir for allograft colonization in patients with cystic fibrosis. Further studies are needed to determine whether treatment of sinusitis affects allograft colonization and transplant outcomes.

Survival after lung transplantation in recipients with alpha-1-antitrypsin deficiency compared to other forms of chronic obstructive pulmonary disease: a national cohort study

Alpha-1-antitrypsin deficiency (AATD) is grouped with chronic obstructive pulmonary disease (COPD); however, this may not be appropriate. This study assessed whether AATD confers a different prognosis than COPD following lung transplantation. We employed the United Network for Organ Sharing (UNOS) database, grouping patients by diagnoses of AATD or COPD. Kaplan-Meier methods and Cox modeling were performed to determine the association of diagnosis and overall survival. Of 9569 patients, 1394 (14.6%) had a diagnosis of AATD. Patients with AATD who received a single-lung transplant had reduced 1-year survival [adjusted hazard ratio (AHR): 1.68, 95% CI: 1.26, 2.23]. Among patients who received a bilateral lung transplant, there was no significant difference in survival by diagnosis (AHR for AATD as compared to COPD: 0.96, 95% CI: 0.82, 1.12). After the implementation of the lung allocation score (LAS), there was no significant difference in survival among patients who received a single (AHR: 1.15, 95% CI: 0.69, 1.95) or bilateral (AHR: 0.99, 95% CI: 0.73, 1.34) lung transplant by diagnosis. Lung transplantation is increasingly employed in the care of the patient with COPD. Although recipients undergoing LTX for AATD are at increased risk of both acute rejection and airway dehiscence post-transplant, in the post-LAS era, survival rates are similar for recipients with AATD in comparison with COPD.