Survival in adult lung transplantation: where are we in 2020?

Temporal correlation between postreperfusion complement deposition and severe primary graft dysfunction in lung allografts

Growing evidence implicates complement in the pathogenesis of primary graft dysfunction (PGD). We hypothesized that early complement activation postreperfusion could predispose to severe PGD grade 3 (PGD-3) at 72 hours, which is associated with worst posttransplant outcomes. Consecutive lung transplant patients (n = 253) from January 2018 through June 2023 underwent timed open allograft biopsies at the end of cold ischemia (internal control) and 30 minutes postreperfusion. PGD-3 at 72 hours occurred in 14% (35/253) of patients; 17% (44/253) revealed positive C4d staining on postreperfusion allograft biopsy, and no biopsy-related complications were encountered. Significantly more patients with PGD-3 at 72 hours had positive C4d staining at 30 minutes postreperfusion compared with those without (51% vs 12%, P < .001). Conversely, patients with positive C4d staining were significantly more likely to develop PGD-3 at 72 hours (41% vs 8%, P < .001) and experienced worse long-term outcomes. In multivariate logistic regression, positive C4d staining remained highly predictive of PGD-3 (odds ratio 7.92, 95% confidence interval 2.97-21.1, P < .001). Hence, early complement deposition in allografts is highly predictive of PGD-3 at 72 hours. Our data support future studies to evaluate the role of complement inhibition in patients with early postreperfusion complement activation to mitigate PGD and improve transplant outcomes.

The cost of lung transplantation in the United States: How high is too high?

Objectives

To identify patient and process factors that contribute to the high cost of lung transplantation (LTx) in the perioperative period, which may allow transplant centers to evaluate situations in which transplantation is most cost-effective to inform judicious resource allocation, avoid futile care, and reduce costs.

Methods

The MarketScan Research databases were used to identify 582 privately insured patients undergoing single or bilateral LTx between 2013 and 2019. The patients were subdivided into groups by disease etiology using the United Network of Organ Sharing classification system. Multivariable generalized linear models using a gamma distribution with a log link were fit to examine the associations between the etiology of lung disease and costs during the index admission, 3 months before admission, and 3 months after discharge.

Results

Our results indicate that the index admission contributed the most to the total transplantation costs compared to the 3 months before admission and after discharge. The regression-adjusted mean index hospitalization cost was 35% higher for patients with pulmonary vascular disease compared to those with obstructive lung disease ($527,156 vs $389,055). The use of extracorporeal membrane oxygenation, mechanical ventilation, and surgical complications in the post-transplantation period were associated with higher costs during the index admission. Surprisingly, age ≥55 was associated with lower costs during the index admission.

Conclusions

This analysis identifies pivotal factors influencing the high cost of LTx, emphasizing the significant impact of the index admission, particularly for patients with pulmonary vascular disease. These insights offer transplant centers an opportunity to enhance cost-effectiveness through judicious resource allocation and service bundling, ultimately reducing overall transplantation costs.

Ventilatory capacity in CLAD is driven by dysfunctional airway structure

BACKGROUND

Chronic lung allograft dysfunction (CLAD) encompasses three main phenotypes: bronchiolitis obliterans syndrome (BOS), restrictive allograft syndrome (RAS) and a Mixed phenotype combining both pathologies. How the airway structure in its entirety is affected in these phenotypes is still poorly understood.

METHODS

A detailed analysis of airway morphometry was applied to gain insights on the effects of airway remodelling on the distribution of alveolar ventilation in end-stage CLAD. Ex vivo whole lung μCT and tissue-core μCT scanning of six control, six BOS, three RAS and three Mixed explant lung grafts (9 male, 9 female, 2014-2021, Leuven, Belgium) were used for digital airway reconstruction and calculation of airway dimensions in relation to luminal obstructions.

FINDINGS

BOS and Mixed explants demonstrated airway obstructions of proximal bronchioles (starting at generation five), while RAS explants particularly had airway obstructions in the most distal bronchioles (generation >12). In BOS and Mixed explants 76% and 84% of bronchioles were obstructed, respectively, while this was 22% in RAS. Bronchiolar obstructions were mainly caused by lymphocytic inflammation of the airway wall or fibrotic remodelling, i.e. constrictive bronchiolitis. Proximal bronchiolectasis and imbalance in distal lung ventilation were present in all CLAD phenotypes and explain poor lung function and deterioration of specific lung function parameters.

INTERPRETATION

Alterations in the structure of conducting bronchioles revealed CLAD to affect alveolar ventilatory distribution in a regional fashion. The significance of various obstructions, particularly those associated with mucus, is highlighted.

FUNDING

This research was funded with the National research fund Flanders (G060322N), received by R.V.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Trends in Survival for Adult Organ Transplantation

Objective

Intent-to-treat analysis follows patients from listing to death, regardless of their transplant status, and aims to provide a more holistic scope of the progress made in adult solid-organ transplantation.

Background

Many studies have shown progress in waitlist and post-transplant survival for adult kidney, liver, heart, and lung transplants, but there is a need to provide a more comprehensive perspective of transplant outcomes for patients and their families.

Methods

Univariable and multivariable Cox regression analyses were used to analyze factors contributing to intent-to-treat survival in 813,862 adults listed for kidney, liver, heart, and lung transplants. The Kaplan-Meier method was used to examine changes in waitlist, post-transplant, and intent-to-treat survival. Transplantation rates were compared using χ2 tests.

Results

Intent-to-treat survival has steadily increased for liver, heart, and lung transplants. The percentage of patients transplanted within 1 year significantly increased for heart (57.4% from 52.9%) and lung (73.5% from 33.2%). However, the percentage of patients transplanted within 1 year significantly decreased from 35.8% to 21.2% for kidney transplant. Notably, intent-to-treat survival has decreased for kidneys despite increases in waitlist and post-transplant survival, likely because of the decreased transplant rate.

Conclusion

Intent-to-treat survival steadily improved for liver, heart, and lung transplant over the 30-year study period. Continued advancements in allocation policy, immunosuppression, and improved care of patients on the waitlist may contribute to further progress in outcomes of all organs, but the increasing discrepancy in supply and demand of donor kidneys is alarming and has impeded the progress of kidney intent-to-treat survival.

Telecoaching as a new training method for elderly people: a systematic review

BACKGROUND

The numerous restrictive measures implemented during the recent COVID-19 pandemic have reduced the levels of physical activity (PA) carried out by elderly people and telecoaching (TC) could be a training method to maintain the recommended levels of PA. In fact, TC uses information and digital communications technologies, such as computers and mobile devices, to access training services remotely. Thus, this study aimed to systematically review the scientific literature to verify the application, efficacy, and safety of TC training programs.

METHODS

PubMed, Scopus, and Web of Sciences databases were used for this review, and randomized controlled trials analyzing TC training programs for elderly people were included. Only articles written in English and published in the last decade were considered.

RESULTS

3 articles were included in the qualitative synthesis including 194 elderly people. The sample size ranged from 12 to 117 and the TC training program from 8 to 12 weeks. The TC training programs were applied to elderly people with metabolic diseases and respiratory diseases. TC training program was effective in elderly people with metabolic diseases while the benefits for respiratory diseases have yet to be clarified.

CONCLUSION

TC seems to be a safe, effective, and injury-free training method, despite its limited application in elderly population. Future studies should better investigate this training method in elderly people in order to evaluate the effectiveness in a wider range of diseases.

Thoracic organ transplantation and pregnancy outcomes: systematic review and meta-analysis

PURPOSE

Pre-conceptual comorbidities, an inherent risk of graft loss, rejection during pregnancy, and the postpartum period in women with thoracic lung transplant may predispose them to increased risk of adverse feto-maternal outcomes. The study aimed to systematically analyze and assess the risk of adverse pregnancy outcomes in women with thoracic organ transplant.

METHODS

MEDLINE, EMBASE, and Cochrane library were searched for publication between January 1990 and June 2020. Risk of bias was assessed using Joanna Briggs critical appraisal tool for case series. The primary outcomes included maternal mortality and pregnancy loss. The secondary outcomes were maternal complications, neonatal complications, and adverse birth outcomes. The analysis was performed using the DerSimonian-Laird random effects model.

RESULTS

Eleven studies captured data from 275 parturient with thoracic organ transplant describing 400 pregnancies. The primary outcomes included maternal mortality {pooled incidence (95% confidence interval) 4.2 (2.5-7.1) at 1 year and 19.5 (15.3-24.5) during follow-up}. Pooled estimates yielded 10.1% (5.6-17.5) and 21.8% (10.9-38.8) risk of rejection and graft dysfunction during and after pregnancy, respectively. Although 67% (60.2-73.2) of pregnancies resulted in live birth, total pregnancy loss and neonatal death occurred in 33.5% (26.7-40.9) and 2.8% (1.4-5.6), respectively. Prematurity and low birth weight were reported in 45.1% (38.5-51.9) and 42.7% (32.8-53.2), respectively.

CONCLUSIONS

Despite pregnancies resulting in nearly 2/3rd of live births, high incidence of pregnancy loss, prematurity and low birth weight remain a cause of concern. Focused pre-conceptual counseling to avoid unplanned pregnancy, especially in women with transplant-related organ dysfunctions and complications, is vital to improve pregnancy outcomes.

PROSPERO NUMBER

CRD42020164020.

[The role of surveillance bronchoscopy after lung transplantation]

The role of surveillance bronchoscopy after lung transplantation. Lung transplantation is currently accepted as a potential treatment for end-stage respiratory diseases. That said, airway complications and the onset of chronic lung allograft dysfunction remain major causes of morbidity and mortality subsequent to lung transplantation and a significant obstacle to long-term survival. In this article, we discuss the advantages and limitations of bronchial endoscopy in post-lung transplant monitoring.

Improvement Gaps to Deal with the Shortage of Lungs for Transplant From a Middle Income Country's Perspective

OBJECTIVES

Our study aimed to identify the potential causes for the low lung procurement rate in Argentina and to develop strategies to the actual problems in donor management focused on lung retrieval.

MATERIALS AND METHODS

We performed a crosssectional study in which we analyzed data obtained from digital self-reported surveys conducted on professionals participating in the organ procurement process in Argentina. The surveys included questions on donor management, selection criteria, and resource availability involving increasing lung procurement.

RESULTS

Among professionals surveyed, 23.7% did not use advanced hemodynamic monitoring in their donor maintenance and limited their use to central venous pressure. Only 35.8% of participants considered maintaining central venous pressure <10 mm Hg during donor maintenance. With regard to donors with severe deterioration of the ejection fraction, 47.4% of participants would not use restrictive fluid, and only 23.2% would use an advanced monitoring of the hemodynamic status to guide fluid management. Only 27.8% of participants routinely would use steroids to improve lung function in donors. With regard to mechanical ventilation, 80.4% of participants used protective ventilation, but only 4.10% used it adequately. Recruitment maneuvers were routinely used by only 3.1% of those surveyed. With regard to expanded selection criteria (age >55 years, smoking habit of >20 packs/year, positive upper airway cultures, unspecific infiltrates in radiography, and >72 hours of mechanical ventilation), 92.8% of surveyed participants would discount patients with some of these expanded selection criteria without considering offering the lungs for donation.

CONCLUSIONS

Opportunities for improvement may involve training physicians involved in the donor maintenance process and reviewing the donor selection criteria used to increase adherence to expanded selection criteria.

Impact of air pollution on postoperative outcomes following organ transplantation: Evidence from clinical investigations

INTRODUCTION

Air pollution is a worldwide problem affecting human health via various body systems, resulting in numerous significant adverse events. Air pollutants, including particulate matter < or = 2.5 microns (PM2.5), particulate matter < or = 10 microns (PM10), ozone (O3 ), nitrogen dioxide (NO2 ), and traffic-related air pollution (TRAP), have demonstrated the negative effects on human health (e.g., increased cerebrovascular, cardiovascular, and respiratory diseases, malignancy, and mortality). Organ transplant patients, who are taking immunosuppressive agents, are especially vulnerable to the adverse effects of air pollutants. The evidence from clinical investigation has shown that exposure to air pollution after organ transplantation is associated with organ rejection, cardiovascular disease, coronary heart disease, cerebrovascular disease, infection-related mortality, and vitamin D deficiency.

OBJECTIVES AND METHOD

This review aims to summarize and discuss the association of exposure to air pollutants and serum 25-hydroxyvitamin D level and outcomes after transplantation. Controversial findings are also included and discussed.

CONCLUSION

All of the findings suggest that air pollution results in a hazardous environment, which not only impacts human health worldwide but also affects post-transplant outcomes.

Molecular monitoring of lung allograft health: is it ready for routine clinical use?

Maintenance of long-term lung allograft health in lung transplant recipients (LTRs) requires a fine balancing act between providing sufficient immunosuppression to reduce the risk of rejection whilst at the same time not over-immunosuppressing individuals and exposing them to the myriad of immunosuppressant drug side-effects that can cause morbidity and mortality. At present, lung transplant physicians only have limited and rather blunt tools available to assist them with this task. Although therapeutic drug monitoring provides clinically useful information about single time point and longitudinal exposure of LTRs to immunosuppressants, it lacks precision in determining the functional level of immunosuppression that an individual is experiencing. There is a significant gap in our ability to monitor lung allograft health and therefore tailor optimal personalised immunosuppression regimens. Molecular diagnostics performed on blood, bronchoalveolar lavage or lung tissue that can detect early signs of subclinical allograft injury, differentiate rejection from infection or distinguish cellular from humoral rejection could offer clinicians powerful tools in protecting lung allograft health. In this review, we look at the current evidence behind molecular monitoring in lung transplantation and ask if it is ready for routine clinical use. Although donor-derived cell-free DNA and tissue transcriptomics appear to be the techniques with the most immediate clinical potential, more robust data are required on their performance and additional clinical value beyond standard of care.

The Evaluation and Management of Coronary Artery Disease in the Lung Transplant Patient

Lung transplantation can greatly improve quality of life and extend survival in those with end-stage lung disease. In order to derive the maximal benefit from such a procedure, patients must be carefully selected and be otherwise healthy enough to survive a high-risk surgery and sometimes prolonged immunosuppressive therapy following surgery. Patients therefore must be critically assessed prior to being listed for transplantation with close attention paid towards assessment of cardiovascular health and operative risk. One of the biggest dictators of this is coronary artery disease. In this review article, we discuss the assessment and management of coronary artery disease in the potential lung transplant candidate.

Telocytes protect against lung tissue fibrosis through hexokinase 2-dependent pathway by secreting hepatocyte growth factor

Pulmonary fibrosis (PF) is one of the common manifestations of end-stage lung disease. Chronic lung failure after lung transplantation is mainly caused by bronchiolitis obliterans syndrome (BOS) and is mainly characterized by lung tissue fibrosis. Pulmonary epithelial-mesenchymal transformation (EMT) is crucial for pulmonary fibrosis. Telocytes (TCs), a new type of mesenchymal cells, play a protective role in various acute injuries. For exploring the anti-pulmonary fibrosis effect of TCs in the BOS model in vitro and the related mechanism, rat tracheal epithelial (RTE) cells were treated with transforming growth factor-β (TGF-β) to simulate lung tissue fibrosis in vitro. The RTE cells were then co-cultured with TCs primarily extracted from rat lung tissue. Western blot, Seahorse XF Analysers and enzyme-linked immunosorbent assay were used to detect the level of EMT and aerobic respiration of RTE cells. Furthermore, anti-hepatocyte growth factor (anti-HGF) antibody was exogenously added to the cultured cells to explore further mechanisms. Moreover, hexokinase 2 (HK2) in RTE cells was knocked down to assess whether it influences the blocking effect of the anti-HGF antibody. TGF-β could induce lung tissue fibrosis in RTE cells in vitro. Nevertheless, TCs co-culture decreased the level of EMT, glucose metabolic indicators (lactate and ATP) and oxygen levels. Furthermore, TCs released hepatocyte growth factor (HGF). Therefore, the exogenous addition of anti-HGF antibody in the co-culture system blocked the anti-lung tissue fibrosis effect. However, HK2 knockdown attenuated the blocking effect of the anti-HGF antibody. In conclusion, TCs can protect against lung tissue fibrosis by releasing HGF, a process dependent on HK2.

Thoracic retransplantation: Does time to retransplantation matter?

OBJECTIVE

For some individuals, chronic allograft failure is best treated with retransplantation. We sought to determine if time to retransplantation impacts short- and long-term outcomes for heart or lung retransplant recipients with a time to retransplantation more than 1 year.

METHODS

The United Network for Organ Sharing/Organ Procurement and Transplantation Network STAR file was queried for all adult, first-time heart (June 1, 2006, to September 30, 2020) and lung (May 1, 2005, to September 30, 2020) retransplantations with a time to retransplantation of at least 1 year. Patients were grouped according to the tertile of time to retransplantation (tertile 1: 1-7.7 years, tertile 2: 7.7-14.7 years, tertile 3: 14.7+ years; lung: tertile 1: 1-2.8 years, tertile 2: 2.8-5.6 years, tertile 3: 5.6+ years). The primary outcome was survival after retransplantation. Comparative statistics identified differences in groups, and Kaplan-Meier methods and a Cox proportional hazard model were used for survival analysis.

RESULTS

After selection, 908 heart and 871 lung retransplants were identified. Among heart retransplant recipients, tertile 1 was associated with male sex, smoking history, higher listing status, and increased mechanical support pretransplant. Tertile 3 had the highest rate of concomitant kidney transplant; however, the incidence of morbidity and in-hospital mortality was similar among the groups. Unadjusted and adjusted analyses revealed no survival difference among all groups. Regarding lung retransplant recipients, tertile 1 was associated with increased lung allocation score, pretransplant hospitalization, and mechanical support. Unadjusted and adjusted survival analyses revealed decreased survival in tertile 1.

CONCLUSIONS

Time to retransplant does not appear to affect heart recipients with a time to retransplantation of more than 1 year; however, shorter time to retransplantation for prior lung recipients is associated with decreased survival. Potential lung retransplant candidates with a time to retransplantation of less than 2.8 years should be carefully evaluated before retransplantation.

Special Considerations and Techniques of Interventions in Lung Transplant Recipients

Lung transplant remains an important treatment option for patients with end-stage lung diseases providing improvement in survival rates and quality of life. Specialized considerations should be applied with interventions of lung transplant recipients as they host specific anatomic variations and high risk towards certain complications. In this article, we highlight the role of interventional radiology for lung transplant recipients along with discussion of interventional techniques. Specific emphasis is placed on describing and explaining the techniques pertained to the points of anastomosis, diagnosis and treatment of malignancies, and management of complications in lung transplant recipients.

Extracorporeal membrane oxygenation in South Africa: Experience from a single centre in the private sector

Background

Extracorporeal membrane oxygenation (ECMO) is an advanced, resource-intensive technology used in a limited capacity in South Africa (SA). Minimal data on the use of ECMO in SA are available.

Objectives

To describe the indications, early outcome and comorbidities of patients placed on ECMO in the highest-volume ECMO centre in SA.

Methods

We performed a single-centre retrospective review of all adult patients supported with any form of ECMO from August 2016 to December 2018. Operative and clinical records were reviewed. The primary objective of this study was to review the outcome of patients placed on ECMO in the form of survival to hospital discharge. The secondary objectives were to identify population-specific comorbidities and indications for ECMO that could be associated with non-survival and to compare outcome with known risk scores in the form of the Respiratory ECMO Survival Prediction (RESP) and Survival After Venoarterial ECMO (SAVE) scores.

Results

One hundred and seven patients were identified. The primary indication for ECMO was respiratory support in 78 patients and cardiac support in 29 patients. Forty-seven patients were discharged from hospital, with a 44.0% overall survival rate. Gender (p=0.039), age (p=0.019) and hypertension (p=0.022) were associated with death in univariate logistic regression analysis. However, after adjusting for potential confounding in multivariate logistic regression analysis, the association was no longer significant. In the all respiratory support group, patients in risk class IV had better than predicted survival according to the RESP score, while risk classes I, II and III had worse than predicted survival. In the circulatory support group, all risk classes had worse than predicted survival according to the SAVE score.

Conclusion

We report ECMO outcomes in SA for the first time. We identified very high mortality rates for patients transferred on ECMO from other facilities and for patients converted from venovenous ECMO to venoarterial ECMO. Although our outcomes were comparable in some of the risk classes, further external validation of the SAVE and RESP scores will be needed to compare our outcomes with these scores.

Study synopsis

What the study adds. We report on extracorporeal membrane oxygenation (ECMO) outcomes in South Africa for the first time. We identified a high mortality rate in patients transferred on ECMO from other facilities, and in patients converted from venovenous ECMO to venoarterial ECMO.Implications of the findings. Transferred patients had a high mortality rate. The reason for this should be further investigated and may highlight the need for possible protocols to assist with appropriate timing of patient transfers and possible earlier intervention or transfer.

Observational Study of the Association between Atrial Fibrillation and In-Hospital Mortality during Hospitalization for Solid Organ Transplants in Spain from 2004 to 2021

(1) Background: We analyzed the association between atrial fibrillation or atrial flutter (AF) and in-hospital mortality (IHM) among patients who underwent solid organ transplants in Spain from 2004 to 2021. (2) Methods: We gathered information from all hospital admissions for lung, liver, kidney, and heart transplants. (3) Results: A total of 71,827 transplants were analyzed (4598 lung transplants; 18,127 liver transplants; 45,262 kidney transplants; and 4734 heart transplants). One third of these were for women. Overall, the prevalence of AF was 6.8% and increased from 5.3% in 2004-2009 to 8.6% in 2016-2021. The highest prevalence of AF was found for heart transplants (24.0%), followed by lung transplants (14.7%). The rates for kidney and liver transplants were 5.3% and 4.1%, respectively. The AF code increased over time for all of the transplants analyzed (p < 0.001). The patients' IHM decreased significantly from 2004-2009 to 2016-2021 for all types of transplants. AF was associated with a higher IHM for all of the types of transplants analyzed, except for heart transplants. (4) Conclusions: The prevalence of AF among patients admitted for solid organ transplants was highest for those who underwent heart transplants. The mortality rate during the patients' admission for lung, liver, kidney, or heart transplants decreased over time. AF was independently associated with a higher risk of dying in the hospital for those who underwent lung, liver, or kidney transplants.

Invasive Aspergillosis among Lung Transplant Recipients during Time Periods with Universal and Targeted Antifungal Prophylaxis-A Nationwide Cohort Study

The optimal prevention strategy for invasive aspergillosis (IA) in lung transplant recipients (LTXr) is unknown. In 2016, the Danish guidelines were changed from universal to targeted IA prophylaxis. Previously, we found higher rates of adverse events in the universal prophylaxis period. In a Danish nationwide study including LTXr, for 2010-2019, we compared IA rates in time periods with universal vs. targeted prophylaxis and during person-time with vs. person-time without antifungal prophylaxis. IA hazard rates were analyzed in multivariable Cox models with adjustment for time after LTX. Among 295 LTXr, antifungal prophylaxis was initiated in 183/193 and 6/102 during the universal and targeted period, respectively. During the universal period, 62% discontinued prophylaxis prematurely. The median time on prophylaxis was 37 days (IQR 11-84). IA was diagnosed in 27/193 (14%) vs. 15/102 (15%) LTXr in the universal vs. targeted period, with an adjusted hazard ratio (aHR) of 0.94 (95% CI 0.49-1.82). The aHR of IA during person-time with vs. person-time without antifungal prophylaxis was 0.36 (95% CI 0.12-1.02). No difference in IA was found during periods with universal vs. targeted prophylaxis. Prophylaxis was protective of IA when taken. Targeted prophylaxis may be preferred over universal due to comparable IA rates and lower rates of adverse events.

Mode of action, indications and recommendations on extracorporeal photopheresis (ECP)

Extracorporeal photopheresis (ECP) has gained importance in the treatment of several diseases. Initially introduced as a new therapeutic modality for the treatment of patients with cutaneous T-cell lymphoma, the indications for the use of ECP have expanded to include hematology and transplantation immunology. Extracorporeal photopheresis has found its place in the treatment plan of cutaneous T-cell lymphoma, systemic sclerosis, graft-versus-host disease, organ transplantation such as heart and lung, sometimes as first-line therapy and very often in combination with various systemic immunosuppressive therapies. The procedure basically consists of three steps: leukapheresis, photoactivation and reinfusion. The following article presents possible theories about the mechanism of action, which is not yet fully understood, and discusses the five most common indications for ECP treatment with corresponding therapy recommendations.

Postoperative Acute Kidney Injury and Long-Term Outcomes After Lung Transplantation

BACKGROUND

This study sought to characterize perioperative risk factors of acute kidney injury (AKI) and report outcomes associated with its development in the immediate postoperative setting after lung transplantation.

METHODS

Study investigator performed a retrospective analysis of all adult patients undergoing primary lung transplantation at a single institution from January 1, 2011 to December 31, 2021 AKI was defined using Kidney Disease: Improving Global Outcomes (KDIGO) criteria after lung transplantation and was stratified on the basis of whether patients required renal replacement therapy (RRT; AKI-no RRT vs AKI-RRT).

RESULTS

Of the 754 patients included, 369 (48.9%) any AKI developed in the postoperative period (252 AKI-no RRT vs 117 AKI-RRT). Risk factors for postoperative AKI included higher preoperative creatinine levels (odds ratio [OR], 5.15; P < .001), lower preoperative estimated glomerular filtration rate (OR, 0.99; P < 0.018), delayed chest closure (OR, 2.72; P < .001), and higher volumes of postoperative blood products (OR, 1.09; P < .001) in the multivariable analysis. On univariate analysis, both AKI groups were also associated with higher rates of pneumonia (P < .001), reintubation (P < .001), mortality on index admission (P < 0.001), longer ventilator duration (P < .001), longer intensive care unit length of stay (P < .001), and longer hospital length of stay (P < .001), with the highest rates in the AKI-RRT group. In a multivariable survival analysis, postoperative AKI-no RRT (hazard ratio [HR], 1.50; P = .006) and AKI-RRT (HR, 2.70; P < .001) were associated with significantly worse survival independent of severe grade 3 primary graft dysfunction at 72 hours (HR, 1.45; P = .038).

CONCLUSIONS

The development of postoperative AKI was associated with numerous preoperative and intraoperative factors. Postoperative AKI remained significantly associated with poorer posttransplantation survival. Severe cases of AKI necessitating RRT portended the worst survival after lung transplantation.

Cystic fibrosis survival outcomes following second lung transplant: The north American experience

INTRODUCTION

Re-transplant is an option for those who develop end-stage lung disease due to rejection; however, little data exist following re-transplantation in cystic fibrosis (CF).

METHODS

Data from the Canadian CF Registry and US CF Foundation Patient Registry supplemented with data from United Network for Organ Sharing were used. Individuals who underwent a 2nd lung transplant between 2005 and 2019 were included. The Kaplan-Meier method was used to estimate the probability of survival post-second transplant at 1, 3, and 5-years.

RESULTS

Of those people who were waitlisted for a second transplant (N = 818), a total of 254 (31%) died waiting, 395 (48%) were transplanted and 169 (21%) people were alive on the waitlist. Median survival time after 2nd lung transplant was 3.3 years (95% CI: 2.8-4.1). The 1-, 3- and 5-year survival rates were 77.4% (95% CI: 73.1-82%), 52% (95% CI: 46.7-58%) and 39.4% (95% CI: 34.1-45.6%).

CONCLUSIONS

Survival following second lung transplant in CF patients is lower than estimates following the first transplant. Over half of subjects who are potentially eligible for a second transplant die without receiving a second organ. This warrants further investigation.

Lymphocyte Depleting and Modulating Therapies for Chronic Lung Allograft Dysfunction

Chronic lung rejection, also called chronic lung allograft dysfunction (CLAD), remains the major hurdle limiting long-term survival after lung transplantation, and limited therapeutic options are available to slow the progressive decline in lung function. Most interventions are only temporarily effective in stabilizing the loss of or modestly improving lung function, with disease progression resuming over time in the majority of patients. Therefore, identification of effective treatments that prevent the onset or halt progression of CLAD is urgently needed. As a key effector cell in its pathophysiology, lymphocytes have been considered a therapeutic target in CLAD. The aim of this review is to evaluate the use and efficacy of lymphocyte depleting and immunomodulating therapies in progressive CLAD beyond usual maintenance immunosuppressive strategies. Modalities used include anti-thymocyte globulin, alemtuzumab, methotrexate, cyclophosphamide, total lymphoid irradiation, and extracorporeal photopheresis, and to explore possible future strategies. When considering both efficacy and risk of side effects, extracorporeal photopheresis, anti-thymocyte globulin and total lymphoid irradiation appear to offer the best treatment options currently available for progressive CLAD patients. SIGNIFICANCE STATEMENT: Effective treatments to prevent the onset and progression of chronic lung rejection after lung transplantation are still a major shortcoming. Based on existing data to date, considering both efficacy and risk of side effects, extracorporeal photopheresis, anti-thymocyte globulin, and total lymphoid irradiation are currently the most viable second-line treatment options. However, it is important to note that interpretation of most results is hampered by the lack of randomized controlled trials.

Associations between invasive aspergillosis and cytomegalovirus in lung transplant recipients: a nationwide cohort study

Cytomegalovirus (CMV) and invasive aspergillosis (IA) cause morbidity among lung transplant recipients (LTXr). Early diagnosis and treatment could improve outcomes. We examined rates of CMV after IA and vice versa to assess whether screening for one infection is warranted after detecting the other. All Danish LTXr, 2010-2019, were followed for IA and CMV for 2 years after transplantation. IA was defined using ISHLT criteria. Adjusted incidence rate ratios (aIRR) were estimated by Poisson regression adjusted for time after transplantation. We included 295 LTXr, among whom CMV and IA were diagnosed in 128 (43%) and 48 (16%). The risk of CMV was high the first 3 months after IA, IR 98/100 person-years of follow-up (95% CI 47-206). The risk of IA was significantly increased in the first 3 months after CMV, aIRR 2.91 (95% CI 1.32-6.44). Numbers needed to screen to diagnose one case of CMV after IA, and one case of IA after CMV was approximately seven and eight, respectively. Systematic screening for CMV following diagnosis of IA, and vice versa, may improve timeliness of diagnosis and outcomes for LTXr.

Wirkweise, Indikationen und Therapieempfehlungen der extrakorporalen Photopherese (ECP)

Die extrakorporale Photopherese (ECP) hat in jüngster Zeit bei der Behandlung verschiedener Krankheiten an Bedeutung gewonnen. Ursprünglich als neue Therapie zur Behandlung von Patienten mit kutanem T‐Zell‐Lymphom vorgestellt, hat sich der Indikationsbereich für die ECP auf Hämatologie und Transplantationsimmunologie erweitert. Die ECP hat ihren festen Platz im Therapieplan bei kutanen T‐Zell‐Lymphomen, systemischer Sklerose, Graft‐versus‐Host‐Erkrankung, Organtransplantationen wie Herz und Lunge, teilweise als Erstlinientherapie und sehr häufig in Kombination mit verschiedenen systemischen immunsuppressiven Therapien. Das Verfahren besteht im Wesentlichen aus drei Schritten: Leukapherese, Photoaktivierung und Reinfusion. Im folgenden Artikel werden die noch nicht vollständig verstandenen Wirkmechanismen dargestellt, die fünf häufigsten Indikationen für die Behandlung mit ECP diskutiert und Therapieempfehlungen für die jeweilige Indikation gegeben.

Regulatory T cells in lung disease and transplantation

Pulmonary disease can refer to the disease of the lung itself or the pulmonary manifestations of systemic diseases, which are often connected to the malfunction of the immune system. Regulatory T (Treg) cells have been shown to be important in maintaining immune homeostasis and preventing inflammatory damage, including lung diseases. Given the increasing amount of evidence linking Treg cells to various pulmonary conditions, Treg cells might serve as a therapeutic strategy for the treatment of lung diseases and potentially promote lung transplant tolerance. The most potent and well-defined Treg cells are Foxp3-expressing CD4+ Treg cells, which contribute to the prevention of autoimmune lung diseases and the promotion of lung transplant rejection. The protective mechanisms of Treg cells in lung disease and transplantation involve multiple immune suppression mechanisms. This review summarizes the development, phenotype and function of CD4+Foxp3+ Treg cells. Then, we focus on the therapeutic potential of Treg cells in preventing lung disease and limiting lung transplant rejection. Furthermore, we discussed the possibility of Treg cell utilization in clinical applications. This will provide an overview of current research advances in Treg cells and their relevant application in clinics.

Chronic Lung Allograft Dysfunction Is Associated with Significant Disability after Lung Transplantation-A Burden of Disease Analysis in 1025 Cases

BACKGROUND

Chronic lung allograft dysfunction (CLAD) is the leading cause of death after the first postoperative years of lung transplantation (LTx).

OBJECTIVE

To assess the number of disability-adjusted life years (DALYs) per patient with severe CLAD.

METHODS

The clinical and demographic data of patients who received their lung transplantation between 2010 and 2020 in the Hanover Medical School (Germany) were evaluated.

RESULTS

A total of 1025 lung transplant patients were followed for a median of 51 months (4.25 years); the median age at transplantation was 52.8 (interquartile range (IQR) 19) years. More than a quarter of transplant patients (271/1025 or 26.4%) developed CLAD, mostly (60%) of the bronchiolitis obliterans syndrome (BOS) phenotype. Of the CLAD patients, 99, or 36.5%, suffered from significant disability, which on average occurred after 2 years (IQR 2.55). The survival of CLAD patients with disability after transplantation was significantly lower compared to that of patients without CLAD (median 4.04 versus 5.41 years). Adjusted to the DALY estimation approach, CLAD patients lost 1.29 life years (YLL) and lived for 0.8 years with their disability (YLD), adding up to 2.09 DALYs (range 1.99-2.72) per patient.

CONCLUSIONS

CLAD after lung transplantation is a major public health problem and is associated with substantial disability and costs. Further work is needed to develop therapeutic interventions that reduce its development.

Circulating donor-derived cell-free DNA as a marker for rejection after lung transplantation

Objective

Recently, circulating donor-derive cell free DNA (dd-cfDNA) has gained growing attention in the field of solid organ transplantation. The aim of the study was to analyze circulating dd-cfDNA levels in graft rejection, ACR and AMR separately for each rejection type compared with non-rejection, and assessed the diagnostic potential of dd-cfDNA levels in predicting graft rejection after lung transplantation.

Methods

A systematic search for relevant articles was conducted on Medline, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases without restriction of languages. The search date ended on June 1, 2023. STATA software was used to analyze the difference between graft rejection, ACR, AMR and stable controls, and evaluate the diagnostic performance of circulating dd-cfDNA in detecting graft rejection.

Results

The results indicated that circulating dd-cfDNA levels in graft rejection, ACR, and AMR were significantly higher than non-rejection (graft rejection: SMD=1.78, 95% CI: 1.31-2.25, I2 = 88.6%, P< 0.001; ACR: SMD=1.03, 95% CI: 0.47-1.59, I2 = 89.0%, P < 0.001; AMR: SMD= 1.78, 95% CI: 1.20-2.35, I2 = 89.8%, P < 0.001). Circulating dd-cfDNA levels distinguished graft rejection from non-rejection with a pooled sensitivity of 0.87 (95% CI: 0.80-0.92) and a pooled specificity of 0.82 (95% CI: 0.76-0.86). The corresponding SROC yield an AUROC of 0.90 (95% CI: 0.87-0.93).

Conclusion

Circulating dd-cfDNA could be used as a non-invasive biomarker to distinguish the patients with graft rejection from normal stable controls.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023440467.

Liproxstatin-1 Alleviates Lung Transplantation-induced Cold Ischemia-Reperfusion Injury by Inhibiting Ferroptosis

BACKGROUND

Primary graft dysfunction, which is directly related to cold ischemia-reperfusion (CI/R) injury, is a major obstacle in lung transplantation (LTx). Ferroptosis, a novel mode of cell death elicited by iron-dependent lipid peroxidation, has been implicated in ischemic events. This study aimed to investigate the role of ferroptosis in LTx-CI/R injury and the effectiveness of liproxstatin-1 (Lip-1), a ferroptosis inhibitor, in alleviating LTx-CI/R injury.

METHODS

LTx-CI/R-induced signal pathway alterations, tissue injury, cell death, inflammatory responses, and ferroptotic features were examined in human lung biopsies, the human bronchial epithelial (BEAS-2B) cells, and the mouse LTx-CI/R model (24-h CI/4-h R). The therapeutic efficacy of Lip-1 was explored and validated both in vitro and in vivo.

RESULTS

In human lung tissues, LTx-CI/R activated ferroptosis-related signaling pathway, increased the tissue iron content and lipid peroxidation accumulation, and altered key protein (GPX4, COX2, Nrf2, and SLC7A11) expression and mitochondrial morphology. In BEAS-2B cells, the hallmarks of ferroptosis were significantly evidenced at the setting of both CI and CI/R compared with the control, and the effect of adding Lip-1 only during CI was much better than that of only during reperfusion by Cell Counting Kit-8. Furthermore, Lip-1 administration during CI markedly relieved LTx-CI/R injury in mice, as indicated by significant improvement in lung pathological changes, pulmonary function, inflammation, and ferroptosis.

CONCLUSIONS

This study revealed the existence of ferroptosis in the pathophysiology of LTx-CI/R injury. Using Lip-1 to inhibit ferroptosis during CI could ameliorate LTx-CI/R injury, suggesting that Lip-1 administration might be proposed as a new strategy for organ preservation.

Incidence of malignancies after lung transplantation and their effect on the outcome. 26 years' experience

Background

Malignancy is a significant, life-limiting complication after lung transplantation (LuTx) and the second common long-term cause of death. We aimed to investigate its incidence and effect on the outcome.

Methods

This is a retrospective observational study. Between 1996 and 2022, n = 627 lung transplantations (LuTx) were performed in our department. We used our institutional database to identify recipients with malignancies after LuTx and examined the malignancies' incidence and mortality.

Results

N = 59 malignancies occurred in n = 55 (8.8%) LuTx recipients. The post-LTx malignancies incidence was 9.4% (59/627). We report the following rates based on their location: n = 17/55 (28,8% of all recipients diagnosed with malignancies) skin, n = 10/55 (16,95%) gastrointestinal, n = 9/55 (15,3%) respiratory, n = 5/55 (8,48%) lymphatic, n = 13/55 (23,6%) other, n = 5 (8,48%) multiple synchronous.During this study period, a total of n = 328 deaths after LuTx was determined. N = 29 (8,84% of all deaths) were malignancy induced, corresponding to a total malignancy-induced mortality of 4.6% (n = 29/627). The majority of deaths were attributed to GI adenocarcinoma and PTLD. Malignancies' origin, primary COPD diagnosis, type, and specific age group were significantly survival-related (p-values <0.05). The most affected organ was skin and showed the best prognosis. PTLD had the fastest and pancreatic the latest onset.

Conclusions

This is the first report of its kind in a large cohort of german LuTx recipients. The prevalence ranking of the three commonest malignancy were skin > colorectal > PTLD. Post-LTx malignancy was the second commonest cause of death. Further studies are needed, while post-LuTx malignomas remain a serious impairment of long-term LuTx survival.

Monitoring regulatory T cells as a prognostic marker in lung transplantation

Lung transplantation is the major surgical procedure, which restores normal lung functioning and provides years of life for patients suffering from major lung diseases. Lung transplant recipients are at high risk of primary graft dysfunction, and chronic lung allograft dysfunction (CLAD) in the form of bronchiolitis obliterative syndrome (BOS). Regulatory T cell (Treg) suppresses effector cells and clinical studies have demonstrated that Treg levels are altered in transplanted lung during BOS progression as compared to normal lung. Here, we discuss levels of Tregs/FOXP3 gene expression as a crucial prognostic biomarker of lung functions during CLAD progression in clinical lung transplant recipients. The review will also discuss Treg mediated immune tolerance, tissue repair, and therapeutic strategies for achieving in-vivo Treg expansion, which will be a potential therapeutic option to reduce inflammation-mediated graft injuries, taper the toxic side effects of ongoing immunosuppressants, and improve lung transplant survival rates.

Diagnostic accuracy of eNose 'breathprints' for therapeutic drug monitoring of Tacrolimus trough levels in lung transplantation

In order to prevent long-term immunity-related complications after lung transplantation, close monitoring of immunosuppressant levels using therapeutic drug monitoring (TDM) is paramount. Novel electronic nose (eNose) technology may be a non-invasive alternative to the current invasive procedures for TDM. We investigated the diagnostic and categorization capacity of eNose breathprints for Tacrolimus trough blood plasma levels (TACtrough) in lung transplant recipients (LTRs). We performed eNose measurements in stable LTR attending the outpatient clinic. We evaluated (1) the correlation between eNose measurements and TACtrough, (2) the diagnostic capacity of eNose technology for TACtrough, and (3) the accuracy of eNose technology for categorization of TACtroughinto three clinically relevant categories (low: <7µg ml-1, medium: 7-10µg ml-1, and high: >10µg ml-1). A total of 186 measurements from 86 LTR were included. There was a weak but statistically significant correlation (r= 0.21,p= 0.004) between the eNose measurements and TACtrough. The root mean squared error of prediction for the diagnostic capacity was 3.186 in the training and 3.131 in the validation set. The accuracy of categorization ranged between 45%-63% for the training set and 52%-69% in the validation set. There is a weak correlation between eNose breathprints and TACtroughin LTR. However, the diagnostic as well as categorization capacity for TACtroughusing eNose breathprints is too inaccurate to be applicable in TDM.

Novel Endpoints in Solid Organ Transplantation: Targeting Patient-reported Outcome Measures

Although solid organ transplantation improves survival and quality of life in many patients with organ failure, treatment complications and side effects can have debilitating consequences for patients. Patient-reported outcome measures (PROMs) capture how patients feel and function, including quality of life, symptoms, and side effects that are assessed directly by patients. Yet, they remain infrequently reported in trials in solid organ transplantation. Barriers to implementing PROMs in trials include uncertainty in selecting appropriate PROMs, concerns about resources limitations, patient burden, and limited evidence to support the psychometric robustness of measures for use in transplant recipients. In recent years, there have been increasing efforts to include patient-reported outcomes that are important to patients in trials to ensure that trials provide patient-centered information for decision-making. This article will provide an overview of PROMs, discuss PROs that are important to solid organ transplant recipients and those that are used in trials in solid organ transplantation, and outline approaches for selecting PROMs for clinical trials.

Survival Benefit of Solid-Organ Transplantation: 10-Year Update

IMPORTANCE

Transplantation has transformed into a burgeoning field that is rapidly evolving to optimize organ distribution and survival outcomes. The years since 2012 (the last comprehensive study) have seen changes in transplantation, such as advances in immunotherapy and novel indices, that necessitate an updated analysis of survival benefit.

DESIGN

Our goal was to determine the survival benefit for solid-organ transplants in the United Network for Organ Sharing (UNOS) database for a three decade period and provide updates on advancements since 2012. Our retrospective analysis examined data containing U.S. patient records from September 1, 1987, to September 1, 2021.

RESULTS

We found that 3,430,272 life-years were saved over our transplant period (4.33 life-years saved per patient); kidney-1,998,492 life-years; liver -767,414; heart-435,312; lung-116,625; pancreas-kidney-123,463; pancreas-30,575; intestine-7901. After matching, 3,296,851 life-years were saved. Life-years saved and median survival increased for all organs between 2012 and 2021. Compared to 2012, median survival increased in kidney (from 12.4 to 14.76 years), liver (from 11.6 to 14.59), heart (9.5 to 11.73), lung (5.2 to 5.63), pancreas-kidney (from 14.5 to 16.88), pancreas (from 13.3 to 16.10). When compared to 2012, the percent transplanted increased in kidney, liver, heart, lung, and intestine, while pancreas-kidney and pancreas show decreased percent transplanted.

CONCLUSION

Our study underscores the tremendous survival benefits of solid organ transplantation (over 3.4 million life-years saved) and shows improvements since 2012. Our study also highlights areas of transplantation, notably pancreas transplants, that may necessitate reinvigorated attention.

Intestinal microbiota links to allograft stability after lung transplantation: a prospective cohort study

Whether the alternated microbiota in the gut contribute to the risk of allograft rejection (AR) and pulmonary infection (PI) in the setting of lung transplant recipients (LTRs) remains unexplored. A prospective multicenter cohort of LTRs was identified in the four lung transplant centers. Paired fecal and serum specimens were collected and divided into AR, PI, and event-free (EF) groups according to the diagnosis at sampling. Fecal samples were determined by metagenomic sequencing. And metabolites and cytokines were detected in the paired serum to analyze the potential effect of the altered microbiota community. In total, we analyzed 146 paired samples (AR = 25, PI = 43, and EF = 78). Notably, we found that the gut microbiome of AR followed a major depletion pattern with decreased 487 species and compositional diversity. Further multi-omics analysis showed depleted serum metabolites and increased inflammatory cytokines in AR and PI. Bacteroides uniformis, which declined in AR (2.4% vs 0.6%) and was negatively associated with serum IL-1β and IL-12, was identified as a driven specie in the network of gut microbiome of EF. Functionally, the EF specimens were abundant in probiotics related to mannose and cationic antimicrobial peptide metabolism. Furthermore, a support-vector machine classifier based on microbiome, metabolome, and clinical parameters highly predicted AR (AUPRC = 0.801) and PI (AUPRC = 0.855), whereby the microbiome dataset showed a particularly high diagnostic power. In conclusion, a disruptive gut microbiota showed a significant association with allograft rejection and infection and with systemic cytokines and metabolites in LTRs.

Association between Hospital-Acquired Pneumonia and In-Hospital Mortality in Solid Organ Transplant Admissions: An Observational Analysis in Spain, 2004-2021

(1) Background: To analyze the association between hospital-acquired pneumonia (HAP) and in-hospital mortality (IHM) during hospital admission for solid organ transplant in Spain during 2004-2021. (2) Methods: We used national hospital discharge data to select all hospital admissions for kidney, liver, heart, and lung transplants. We stratified the data according to HAP status. To examine time trends, we grouped data into three consecutive 6-year periods (2004-2009; 2010-2015; and 2016-2021). We assessed in-hospital mortality (IHM) in logistic regression analyses and obtained odds ratios (ORs) with their 95% confidence intervals (CIs). (3) Results: We identified a total of 71,827 transplants (45,262, kidney; 18,127, liver; 4734, heart; and 4598, lung). Two thirds of the patients were men. Overall, the rate of HAP during admission was 2.6% and decreased from 3.0% during 2004-2009 to 2.4% during 2016-2021. The highest rate of HAP corresponded to lung transplant (9.4%), whereas we found the lowest rate for kidney transplant (1.1%). Rates of HAP for liver and heart transplants were 3.8% and 6.3%, respectively. IHM was significantly lower during 2016-2021 compared to 2004-2009 for all types of transplants (ORs (CIs) = 0.65 (0.53-0.79) for kidney; 0.73 (0.63-0.84) for liver; 0.72 (0.59-0.87) for heart; and 0.39 (0.31-0.47) for lung). HAP was associated with IHM for all types of transplants (ORs (CIs) = 4.47 (2.85-9.08) for kidney; 2.96 (2.34-3.75) for liver; 1.86 (1.34-2.57) for heart; and 2.97 (2.24-3.94) for lung). (4) Conclusions: Rates of HAP during admission for solid organ transplant differ depending on the type of transplant. Although IHM during admission for solid organ transplant has decreased over time in our country, HAP persists and is associated with a higher IHM after accounting for potential confounding variables.

Lung Transplantation Outcomes in Recipients Aged 70 Years or Older and the Impact of Center Volume

OBJECTIVE

To evaluate trends and outcomes of lung transplants (LTx) in recipients ≥ 70 years.

METHODS

We performed a retrospective analysis of the UNOS database identifying all patients undergoing LTx (May 2005-December 2022). Baseline characteristics and postoperative outcomes were compared by age (<70 years, ≥70 years) and center volume. Kaplan-Meier analyses were performed with pairwise comparisons between subgroups.

RESULTS

34,957 patients underwent LTx, of which 3236 (9.3%) were ≥70 years. The rate of LTx in recipients ≥ 70 has increased over time, particularly in low-volume centers (LVCs); consequently, high-volume centers (HVCs) and LVCs perform similar rates of LTx for recipients ≥ 70. Recipients ≥ 70 had higher rates of receiving from donor after circulatory death lungs and of extended donor criteria. Recipients ≥ 70 were more likely to die of cardiovascular diseases or malignancy, while recipients < 70 of chronic primary graft failure. Survival time was shorter for recipients ≥ 70 compared to recipients < 70 old (hazard ratio (HR): 1.36, 95% confidence interval (CI): 1.28-1.44, p < 0.001). HVCs were associated with a survival advantage in recipients < 70 (HR: 0.91, 95% CI: 0.88-0.94, p < 0.001); however, in recipients ≥ 70, survival was similar between HVCs and LVCs (HR: 1.11, 95% CI: 0.99-1.25, p < 0.08). HVCs were more likely to perform a bilateral LTx (BLT) for obstructive lung diseases compared to LVCs, but there was no difference in BLT and single LTx likelihood for restrictive lung diseases.

CONCLUSIONS

Careful consideration is needed for recipient ≥ 70 selection, donor assessment, and post-transplant care to improve outcomes. Further research should explore strategies that advance perioperative care in centers with low long-term survival for recipients ≥ 70.

Tolerability and Feasibility of the Upper Esophageal Sphincter Assist Device in Preventing Acute and Chronic Allograft Rejection Among Lung Transplant Recipients

GOALS

We aimed to evaluate a novel upper esophageal sphincter (UES) assist device loaner program for the prevention of acute cellular rejection and chronic lung allograft dysfunction among lung transplant (LTx) recipients.

BACKGROUND

Laryngopharyngeal reflux can lead to chronic microaspiration and LTx rejection. The UES assist device applies external pressure at the level of UES to decrease reflux.

STUDY

We prospectively enrolled and issued UES assist devices to consecutive transplant patients referred for gastrointestinal motility testing from 2016 to 2020. Device tolerability was defined by successful utilization as a bridge to ambulatory pH monitoring and/or antireflux procedure, or as permanent therapy. Incidence of rejection was analyzed before, during, and after device implementation.

RESULTS

Twenty-six participants were issued devices (15 pathologic, 5 physiological, 6 unknown reflux status), none of whom developed acute rejection episodes or chronic lung allograft dysfunction while using the device. Thirteen adopted the device promptly after transplantation (mean 1.7 mo) and remained free of rejection episodes over a mean 24.7 months of follow-up. Among those with pathologic reflux, lag time to device adoption strongly correlated with the development of rejection ( r =0.8, P =0.0006). There was no such correlation among those with physiological reflux. Five developed acute rejection after device return.

CONCLUSIONS

The device was tolerated by a majority of LTx patients and appears feasible as a barrier measure in the prevention of rejection. Delayed treatment of laryngopharyngeal reflux may lead to early allograft failure; therefore, the UES assist device should be given important consideration in transplant protection.

Conditional Survival in Lung Transplantation: An Organ Procurement and Transplantation Network Database Analysis

Lung transplantation survival estimates are traditionally reported as fixed 1-, 5-, and 10-year mortality rates. Alternatively, this study aims to demonstrate how conditional survival models can provide useful prognostic information tailored to the time a recipient has already survived from the date of transplantation. Recipient data was obtained from the Organ Procurement and Transplantation Network database. Data from 24,820 adult recipients over age 18 who received a lung transplant between 2002 and 2017 were included in the study. Five-year observed conditional survival estimates were calculated by recipient age, sex, race, transplant indication, transplant type ( i.e. , single or double), and renal function at the time of transplantation. Significant variability exists in conditional survival following lung transplantation. Each specific recipient characteristic significantly impacted conditional survival during at least one time point in the first 5 years. Younger age and double lung transplantation were the two most positive predictors of improved conditional survival consistently throughout the 5-year study period. Conditional survival in lung transplantation recipients changes over time and across recipient characteristics. Hazards of mortality are not fixed and need to be dynamically evaluated as a function of time. Conditional survival calculations can provide more accurate prognostic predictions than unconditional survival estimates.

Tissue-resident memory T cells and lung immunopathology

Rapid reaction to microbes invading mucosal tissues is key to protect the host against disease. Respiratory tissue-resident memory T (TRM ) cells provide superior immunity against pathogen infection and/or re-infection, due to their presence at the site of pathogen entry. However, there has been emerging evidence that exuberant TRM -cell responses contribute to the development of various chronic respiratory conditions including pulmonary sequelae post-acute viral infections. In this review, we have described the characteristics of respiratory TRM cells and processes underlying their development and maintenance. We have reviewed TRM -cell protective functions against various respiratory pathogens as well as their pathological activities in chronic lung conditions including post-viral pulmonary sequelae. Furthermore, we have discussed potential mechanisms regulating the pathological activity of TRM cells and proposed therapeutic strategies to alleviate TRM -cell-mediated lung immunopathology. We hope that this review provides insights toward the development of future vaccines or interventions that can harness the superior protective abilities of TRM cells, while minimizing the potential for immunopathology, a particularly important topic in the era of coronavirus disease 2019 (COVID-19) pandemic.

Current and future role of double-lung transplantation for bilateral lung cancer

Technological advances have progressively enhanced the survival rate of lung transplant recipients and expanded its indications for various diseases, including the recent coronavirus disease 2019 (COVID-19). However, according to the International Society for Heart and Lung Transplantation, lung cancer constituted a mere 0.1% of the indications for lung transplantation over the past two decades. This statistic has remained stagnant, and numerous lung cancer patients continue to be excluded from lung transplantation candidacy. Contrary to the general exclusion of lung cancer patients from transplantation, the post-transplant survival rate for these patients is not inferior to that of patients with non-cancerous diseases. Furthermore, lung transplantation may offer curative treatment for patients with bilateral lung cancer whose respiratory insufficiency has advanced independently of cancer progression. This review aims to elucidate and examine the role of double lung transplantation (DLT) in bilateral lung cancer. We summarize the established indications for lung transplantation, appropriate histologic or molecular subtypes of lung cancer for transplantation, technical advances to minimize recurrence, post-DLT survival outcomes for lung cancer patients, and related translational research. We suggest that although DLT for bilateral lung cancer presents challenges, it may be considered a potential treatment option in select circumstances.

Trends and Outcomes in Lung Transplantation in Patients with and without Idiopathic Pulmonary Fibrosis in Spain during the Period 2016-2020

(1) Background: This paper aims to assess temporal trends (2016-2020) in incidence, patient's characteristics, complications, length of hospital stay (LOHS) and in-hospital mortality (IHM) among patients with and without idiopathic pulmonary fibrosis (IPF) undergoing lung transplantation (LTx). We also analyse the effect of the COVID-19 pandemic on LTx in these populations. (2) Methods: A retrospective, population-based observational study was conducted using the Spanish National Hospital Discharge Database. Multivariable adjustment was conducted with logistic regression to analyse the IHM. (3) Results: We identified 1777 admissions for LTx during the study period, of which 573 (32.2%) were performed in patients with IPF. The number of hospital admissions for LTx rose from 2016 to 2020, both in patients with and without IPF, but a marked reduction was observed from year 2019 to year 2020. Over time, the proportion of single LTx decreased and bilateral LTx increased significantly in both groups. The incidence of LTx complications increased significantly over time along with the increase in the incidence of IPF. No significant differences in the incidence of complications or in the IHM between patients with and without IPF were found. Suffering any complication of the LTx and pulmonary hypertension were conditions positively associated with IHM in patients with and without IPF. The IHM remained stable from 2016 to 2020 in both study populations and was not affected by the COVID pandemic. (4) Conclusions: Patients with IPF account for almost a third of all lung transplants. The number of LTx increased over time in patients with and without IPF, but a marked reduction was observed from 2019 to 2020. Although the proportion of LTx complications increased significantly over time in both groups, the IHM did not change. IPF was not associated with increased complications or IHM after LTx.

Laparoscopic fundoplication after lung transplantation does not appear to alter lung function trajectory

BACKGROUND

The primary aim of this study was to determine if allograft function in lung transplant (LTx) recipients improves or stabilizes after laparoscopic fundoplication (LF). The secondary aim was to examine the differences in forced expiratory volume in 1 second (FEV1) before and after LF for various subgroups to identify patients who obtained a superior respiratory outcome after LF, and potential predictive factors for this outcome.

METHODS

Retrospective analysis of consecutive LTx recipients undergoing LF at a single centre in Brisbane, Australia between 2004 and 2018. 149/431 proceeded to LF after clinical review and pH study. Regular pre- and post-fundoplication pulmonary function tests were collected from participants. Data were analyzed with linear mixed models, random intercept models, the Reliable Change Index (RCI), and graphical and visual analysis of the trajectory of FEV1.

RESULTS

There was 100% follow-up. After Bonferroni adjustment for multiple comparison was performed, none of the models demonstrated statistical significance. The Reliable Change Index showed one patient had a significant improvement in lung function across that time period, while nine had a significant reduction. The rate of change before and after LF was similar for the 132/149 patients for whom the first and last pre- and post-LF FEV1 values were available. A subset of patients had a considerable reduction in their FEV1 in the peri-operative period (i.e., a large difference between the first measurement post-LF and the final measurement pre-LF).

CONCLUSION

In the largest published cohort to date, LF performed in a high-volume center did not appear to alter the reduction in allograft function seen with time.

Ferulic Acid: A Review of Pharmacology, Toxicology, and Therapeutic Effects on Pulmonary Diseases

Ferulic acid (FA), a prevalent dietary phytochemical, has many pharmacological effects, including anti-oxidation and anti-inflammation effects, and has been widely used in the pharmaceutical, food, and cosmetics industries. Many studies have shown that FA can significantly downregulate the expression of reactive oxygen species and activate nuclear factor erythroid-2-related factor-2/heme oxygenase-1 signaling, exerting anti-oxidative effects. The anti-inflammatory effect of FA is mainly related to the p38 mitogen-activated protein kinase and nuclear factor-kappaB signaling pathways. FA has demonstrated potential clinical applications in the treatment of pulmonary diseases. The transforming growth factor-β1/small mothers against decapentaplegic 3 signaling pathway can be blocked by FA, thereby alleviating pulmonary fibrosis. Moreover, in the context of asthma, the T helper cell 1/2 imbalance is restored by FA. Furthermore, FA ameliorates acute lung injury by inhibiting nuclear factor-kappaB and mitogen-activated protein kinase pathways via toll-like receptor 4, consequently decreasing the expression of downstream inflammatory mediators. Additionally, there is a moderate neuraminidase inhibitory activity showing a tendency to reduce the interleukin-8 level in response to influenza virus infections. Although the application of FA has broad prospects, more preclinical mechanism-based research should be carried out to test these applications in clinical settings. This review not only covers the literature on the pharmacological effects and mechanisms of FA, but also discusses the therapeutic role and toxicology of FA in several pulmonary diseases.

Lung development and regeneration: newly defined cell types and progenitor status

The lung is the most critical organ of the respiratory system supporting gas exchange. Constant interaction with the external environment makes the lung vulnerable to injury. Thus, a deeper understanding of cellular and molecular processes underlying lung development programs and evaluation of progenitor status within the lung is an essential part of lung regenerative medicine. In this review, we aim to discuss the current understanding of lung development process and regenerative capability. We highlight the advances brought by multi-omics approaches, single-cell transcriptome, in particular, that can help us further dissect the cellular player and molecular signaling underlying those processes.

Health-related quality of life following lung transplantation for cystic fibrosis: A systematic review

BACKGROUND

Lung transplantation represents the definite treatment for CF patients with advanced-stage pulmonary disease. Recent major developments in the treatment of CF indicate the need for an evaluation of lung transplantation as the current best practice in end-stage disease. This systematic review was performed to evaluate the impact of lung transplantation on health-related quality of life in patients with CF.

METHODS

PubMed was searched for studies matching the eligibility criteria between January 2000 and January 2022. OVID (MEDLINE), Google Scholar, and EBSCOhost (EMBASE) as well as bibliographies of included studies were also reviewed. Applying predetermined eligibility criteria, the included studies were selected. Predetermined forms were used to conduct a quality appraisal and implement data tabulation. Results were synthesized by narrative review. This systematic review was prospectively registered in the PROSPERO register (CRD 42022341942).

RESULTS

Ten studies (1494 patients) were included. Lung transplantation results in improvements in HRQoL in CF patients relative to their baseline waitlisted state. Up to five years postoperatively CF patients retain their HRQoL at levels similar to the general population. There are several modulating factors that impact HRQoL outcomes in CF patients post-LTx. Compared to lung recipients with other diagnoses CF patients achieve either greater or equal levels of HRQoL.

CONCLUSION

Lung transplantation conveys improved HRQoL to CF patients with the advanced-stage pulmonary disease for up to five years, and to levels comparable to the general population and non-waitlisted CF patients. This systematic review quantifies, using current evidence, the improvements in HRQoL gained by CF patients following lung transplantation.

Interventional pulmonology techniques in lung transplantation

Lung transplantation is a key therapeutic option for several end-stage lung diseases. Interventional pulmonology techniques, mostly bronchoscopy, play a key role throughout the whole path of lung transplantation, from donor evaluation to diagnosis and management of post-transplant complications. We carried out a non-systematic, narrative literature review aimed at describing the main indications, contraindications, performance characteristics and safety profile of interventional pulmonology techniques in the context of lung transplantation. We highlighted the role of bronchoscopy during donor evaluation and described the debated role of surveillance bronchoscopy (with bronchoalveolar lavage and transbronchial biopsy) to detect early rejection, infections and airways complications. The conventional (transbronchial forceps biopsy) and the new techniques (i.e. cryobiopsy, biopsy molecular assessment, probe-based confocal laser endomicroscopy) can detect and grade rejection. Several endoscopic techniques (e.g. balloon dilations, stent placement, ablative techniques) are employed in the management of airways complications (ischemia and necrosis, dehiscence, stenosis and malacia). First line pleural interventions (i.e. thoracentesis, chest tube insertion, indwelling pleural catheters) may be useful in the context of early and late pleural complications occurring after lung transplantation. High quality studies are advocated to define endoscopic standard protocols and thus help improving long-term prognostic outcomes of lung transplant recipients.