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.

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 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.

Investigating the accuracy of blood oxygen saturation measurements in common consumer smartwatches.

Blood oxygen saturation (SpO2) is an important measurement for monitoring patients with acute and chronic conditions that are associated with low blood oxygen levels. While smartwatches may provide a new method for continuous and unobtrusive SpO2 monitoring, it is necessary to understand their accuracy and limitations to ensure that they are used in a fit-for-purpose manner. To determine whether the accuracy of and ability to take SpO2 measurements from consumer smartwatches is different by device type and/or by skin tone, our study recruited patients aged 18-85 years old, with and without chronic pulmonary disease, who were able to provide informed consent. The mean absolute error (MAE), mean directional error (MDE) and root mean squared error (RMSE) were used to evaluate the accuracy of the smartwatches as compared to a clinical grade pulse oximeter. The percent of data unobtainable due to inability of the smartwatch to record SpO2 (missingness) was used to evaluate the measurability of SpO2 from the smartwatches. Skin tones were quantified based on the Fitzpatrick (FP) scale and Individual Typology Angle (ITA), a continuous measure of skin tone. A total of 49 individuals (18 female) were enrolled and completed the study. Using a clinical-grade pulse oximeter as the reference standard, there were statistically significant differences in accuracy between devices, with Apple Watch Series 7 having measurements closest to the reference standard (MAE = 2.2%, MDE = -0.4%, RMSE = 2.9%) and the Garmin Venu 2s having measurements farthest from the reference standard (MAE = 5.8%, MDE = 5.5%, RMSE = 6.7%). There were also significant differences in measurability across devices, with the highest data presence from the Apple Watch Series 7 (88.9% of attempted measurements were successful) and the highest data missingness from the Withings ScanWatch (only 69.5% of attempted measurements were successful). The MAE, RMSE and missingness did not vary significantly across FP skin tone groups, however, there may be a relationship between FP skin tone and MDE (intercept = 0.04, beta coefficient = 0.47, p = 0.04). No statistically significant difference was found between skin tone as measured by ITA and MAE, MDE, RMSE or missingness.

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.

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.

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.

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.

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.

Contemporary trends in PGD incidence, outcomes, and therapies.

BACKGROUND: We sought to describe trends in extracorporeal membrane oxygenation (ECMO) use, and define the impact on PGD incidence and early mortality in lung transplantation. METHODS: Patients were enrolled from August 2011 to June 2018 at 10 transplant centers in the multi-center Lung Transplant Outcomes Group prospective cohort study. PGD was defined as Grade 3 at 48 or 72 hours, based on the 2016 PGD ISHLT guidelines. Logistic regression and survival models were used to contrast between group effects for event (i.e., PGD and Death) and time-to-event (i.e., death, extubation, discharge) outcomes respectively. Both modeling frameworks accommodate the inclusion of potential confounders. RESULTS: A total of 1,528 subjects were enrolled with a 25.7% incidence of PGD. Annual PGD incidence (14.3%-38.2%, p = .0002), median LAS (38.0-47.7 p = .009) and the use of ECMO salvage for PGD (5.7%-20.9%, p = .007) increased over the course of the study. PGD was associated with increased 1 year mortality (OR 1.7 [95% C.I. 1.2, 2.3], p = .0001). Bridging strategies were not associated with increased mortality compared to non-bridged patients (p = .66); however, salvage ECMO for PGD was significantly associated with increased mortality (OR 1.9 [1.3, 2.7], p = .0007). Restricted mean survival time comparison at 1-year demonstrated 84.1 days lost in venoarterial salvaged recipients with PGD when compared to those without PGD (ratio 1.3 [1.1, 1.5]) and 27.2 days for venovenous with PGD (ratio 1.1 [1.0, 1.4]). CONCLUSIONS: PGD incidence continues to rise in modern transplant practice paralleled by significant increases in recipient severity of illness. Bridging strategies have increased but did not affect PGD incidence or mortality. PGD remains highly associated with mortality and is increasingly treated with salvage ECMO.

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.

Survival difference between high-risk and low-risk CFTR genotypes after lung transplant.

BACKGROUND: While cystic fibrosis transmembrane conductance regulator (CFTR) genotypes are associated with clinical outcomes in cystic fibrosis patients, it is unknown if genotype impacts lung transplant outcomes. We sought to compare lung transplant survival and time to bronchiolitis obliterans syndrome (BOS) between high-risk, low-risk, and not yet classified CFTR genotypes. METHODS: We used merged data from the Organ Procurement and Transplantation Network (2005-2017) and United States Cystic Fibrosis Foundation Patient Registry (2005-2016). Cox Proportional Hazards models compared graft failure after lung transplant and time to BOS among high-risk, low-risk, and not yet classified risk CFTR genotype classes. RESULTS: Among 1,830 cystic fibrosis lung transplant recipients, median survival for those with low-risk, high-risk, and not yet classified genotype was 9.83, 6.25, and 5.75 years, respectively. Adjusted Cox models showed recipients with a low-risk genotype had 39% lower risk of death or re-transplant compared to those with high-risk genotype (adjusted HR 0.61, 95% CI = 0.40, 0.91). A subset of 1,585 lung transplant recipients were included in the BOS subgroup analysis. Adjusted analyses showed no significant difference of developing BOS among high-risk, low-risk, or not yet classified genotypes. CONCLUSIONS: Lung transplant recipients with low-risk CFTR genotype have better survival after transplant compared to recipients with high-risk or not yet classified genotypes. Given these differences, future studies evaluating the mechanism by which CFTR genotype affects post-transplant survival could identify potential targets for intervention.

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.

Pretransplant physical frailty, postoperative delirium, and short-term outcomes among older lung transplant recipients.

PURPOSE: Delirium is a common, complex medical challenge that faces surgical patients in the postoperative period. Patients undergoing lung transplantation are at especially high risk given their predisposition to physical frailty and prolonged hospitalization. We sought to investigate the relationship between physical frailty, delirium, and short-term lung transplantation outcomes. MATERIALS AND METHODS: A retrospective study of adult patients who underwent lung transplantation was conducted. Pretransplant frailty markers, including the six-minute walk distance (6MWD) and short physical performance battery (SPPB), and postoperative outcomes, including the incidence of primary graft dysfunction (PGD) and the number of hospital free days alive in the 90-day interval following lung transplantation, were evaluated for association with delirium. RESULTS: A total of 100 patients were included, 38% of whom experienced delirium. Greater pretransplant SPPB scores (indicating lower physical frailty) associated with a lower incidence of postoperative delirium. Postoperative delirium also associated with the number of hospital free days alive, independent of PGD. CONCLUSION: Pretransplant frailty is associated with greater incidence of postoperative delirium, which associated with fewer days alive outside of the hospital. Targeting frailty and postoperative delirium may be modifiable risk factors to improve short-term clinical outcomes.

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

INTRO: Textbook surgical outcome (TO) is a novel composite quality measure in lung transplantation (LTx). Compared to 1-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. METHODS: Adult patients who underwent isolated LTx between 2016 and 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 h 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 h. Recipient and donor characteristics and post-transplant outcomes were compared between patients who achieved and failed TO. RESULTS: 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 < .0001). Among 62 centers, adjusted rates of TO ranged from 27.0% to 72.4% reflecting a wide variability in center-level performance. CONCLUSION: 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.

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.

Associations between resources and practices of ILD centers and outcomes in patients with idiopathic pulmonary fibrosis: data from the IPF-PRO Registry.

BACKGROUND: Performance benchmarks for the management of idiopathic pulmonary fibrosis (IPF) have not been established. We used data from the IPF-PRO Registry, an observational registry of patients with IPF managed at sites across the US, to examine associations between the characteristics of the enrolling sites and patient outcomes. METHODS: An online survey was used to collect information on the resources, operations, and self-assessment practices of IPF-PRO Registry sites that enrolled ≥ 10 patients. Site variability in 1-year event rates of clinically relevant outcomes, including death, death or lung transplant, and hospitalization, was assessed. Models were adjusted for differences in patient case mix by adjusting for known predictors of each outcome. We assessed whether site-level heterogeneity existed for each patient-level outcome, and if so, we investigated potential drivers of the heterogeneity. RESULTS: All 27 sites that enrolled ≥ 10 patients returned the questionnaire. Most sites were actively following > 100 patients with IPF (70.4%), had a lung transplant program (66.7%), and had a dedicated ILD nurse leader (77.8%). Substantial heterogeneity was observed in the event rates of clinically relevant outcomes across the sites. After controlling for patient case mix, there were no outcomes for which the site variance component was significantly different from 0, but the p-value for hospitalization was 0.052. Starting/completing an ILD-related quality improvement project in the previous 2 years was associated with a lower risk of hospitalization (HR 0.60 [95% CI 0.44, 0.82]; p = 0.001). CONCLUSIONS: Analyses of data from patients with IPF managed at sites across the US found no site-specific characteristics or practices that were significantly associated with clinically relevant outcomes after adjusting for patient case mix. Trial registration ClinicalTrials.gov, NCT01915511. Registered 5 August 2013, https://clinicaltrials.gov/ct2/show/NCT01915511.