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

Atrial arrhythmias following lung transplantation: A state of the art review

Lung transplantation (LT) is now an accepted therapy for end stage lung disease in appropriate patients. Atrial arrhythmias (AA) can occur after LT. Early AA after LT are most often atrial fibrillation, whereas late arrhythmias which occur many months or years after LT are often atrial tachycardia. The causes of AA are multifactorial. The review begins with a brief history of LT and AA. This review further describes the pathophysiology of the AA. The risk factors, incidence, recipient characteristics including intra-operative factors are elaborated on. Since there are no clear and specific guidelines on the management of atrial arrhythmia following LT, the recommended guidelines on the management of AA in general are often extrapolated and used in the setting of post LT arrhythmia. The strategy of rate control vs rhythm control is discussed. The pros and cons of various drug regimen, need for direct current cardioversion and catheter ablation therapies are considered. Possible methods to prevent or reduce the incidence of AA after LT are considered. The impact of AA on the short-term and long-term outcomes following LT is discussed.

Incidental Cold Agglutinins in Lung Transplant Recipients

Background

The relevance of cold agglutinins in lung transplantation (LTx) recipients is unclear. While there is typically no intentionally induced hypothermia, the cold preservation of organs could potentially lead to microvascular injury and vascular occlusion after implantation and reperfusion in the presence of cold agglutinins. This study aims to analyze the impact of cold agglutinins in lung transplant recipients on short- and long-term outcomes after LTx.

Methods

We retrospectively analyzed the medical records of 251 patients who underwent LTx at our institution between March 2003 and June 2023. One hundred seventy-three patients were included in the study. Statistical analysis was performed using SPSS and GraphPad software.

Results

One hundred seventy-three of 251 (69%) of the lung transplant recipients were tested for cold agglutinins, which were positive in 78 of 173 (45%) patients. Most had a temperature amplitude of 4 °C; a broader temperature amplitude was detected in 9 of 78 (12%) patients. While there was no effect on overall long-term survival, cold agglutinins were associated with an increased incidence of reperfusion edema (P = 0.0002), severe primary graft dysfunction grade 2/3 (PGD2/3; P = 0.001), and early postoperative thromboembolism (P = 0.04). Multivariate analysis revealed PGD2/3 and thromboembolism as independent predictors of reduced long-term survival (P = 0.003 and P = 0.003, respectively). Plasmapheresis shortly before LTx in selected patients with a high cold agglutinin titer and broad temperature amplitude removed the cold agglutinins for at least 2 mo with good patient outcomes.

Conclusions

Cold agglutinins are associated with an increased incidence of reperfusion edema, PGD2/3, and early postoperative thromboembolism after LTx. Further studies are warranted to evaluate the benefits of regular screening.

Cryoanalgesia in Lung Transplantation - A Systematic Review and Meta-analysis

Background

Lung transplantation is a crucial treatment for end-stage lung diseases. However, postoperative pain management remains a significant challenge. Therefore, this study aims to examine the implications of adoption cryoanalgesia on lung transplantation pain control protocol.

Methods

Three databases were searched for studies comparing cryoanalgesia versus standard of care analgesia in patients after lung transplantation. The primary outcome was opioid consumption throughout the entire hospitalization, at postoperative day (POD) 7 and at POD 14 addressed with Morphine Milligram Equivalents (MME). The secondary outcomes were maximum reported pain score at POD 7, hospital length of stay (LOS) and time until extubation. Mean differences (MDs) with 95% confidence intervals (CIs) were calculated for continuous outcomes.

Results

A total of 5 studies encompassing 485 patients undergoing lung transplantation were included, of whom 228 underwent cryoanalgesia. Compared to standard of care, cryoanalgesia demonstrated significant reduction in opioid consumption at POD 7 (MD: -96.79 MME, 95% CI -183.40 to -10.18, p=0.03), at POD 14 (MD -225,26 MME; 95% CI -366.58 to -83.94; p<0.01) and throughout the entire hospitalization (MD: -307.76 MME, 95% CI -461.72 to -153.79, p<0.01). In addition, there was a significant reduction in pain scores in the cryoanalgesia group (MD: -1.10 points, 95% CI -1.77 to -0.43, p<0.01). However, no significant differences were found regarding hospital LOS or time until extubation.

Conclusions

This meta-analysis indicates that cryoanalgesia effectively reduces opioid requirements and pain levels in lung transplant patients.

Perioperative complications and mid-term outcomes in total hip and knee joint arthroplasty among solid organ transplant recipients: lowest reoperation-free survival and patient survivorship in lung transplant recipients

INTRODUCTION

Performing total joint replacements (TJR) in patients with solid organ transplantations (SOT) is associated with an increased risk of complications and reoperation. The aim of this study is to report on implant survivorship, patient survivorship, and complication rates for total knee arthroplasty (TKA) and total hip arthroplasty (THA) performed in heart, lung, liver and kidney transplant recipients.

MATERIALS AND METHODS

Forty patients with heart, lung, liver, or kidney transplants who underwent primary THA or TKA between January 1, 2013, and July 31, 2023, were included. Implant survivorship, reoperation-free survivorship, patient survivorship, and complication rates were compared between the subgroups.

RESULTS

At a mean follow-up of 5.18 years, Implant survivorship and reoperation-free survival for the entire cohort at the last follow-up were 97.5% and 85%, respectively. Kaplan-Meier survival estimates demonstrated 5- and 10-year reoperation-free survival rates of 86.5% (95% CI: 76%-98.4%) and 57.6% (95% CI: 25.6%-100%), respectively. The lung transplant group had the shortest reoperation-free survival, although not statistically significant (p = 0.07), a significantly higher risk of reoperation, with a hazard ratio (HR) of 6.9 (95% CI: 1.1-41.2, p = 0.04) and both the lowest 5-year patient survivorship at 68.6% (p = 0.04) and the highest risk of death after TJR with a HR of 7 (95% CI: 1.2-45.5, p = 0.03).

CONCLUSION

Patients with SOT exhibit excellent mid-term implant survivorship, with a rate of 97.5%. Lung transplant recipients show the lowest rates of both reoperation-free survival and overall patient survivorship compared to heart, kidney, and liver transplant recipients. Despite this, the 90-day complication rates are similar across all organ groups.

Rescue kidneys in lung transplantation: A retrospective analysis of recipients who might have benefitted from a kidney safety net

BACKGROUND

In 2023, a new United Network for Organ Sharing (UNOS) policy established criteria for a kidney allocation safety net for lung transplant recipients (LTRs) with chronic renal dysfunction. We sought to evaluate the demographics and outcomes of past lung transplant recipients who would have been eligible for a rescue kidney under the new criteria.

METHODS

Using the UNOS Organ Procurement and Transplantation Network (OPTN) registry, we identified lung transplant recipients from 2005 to 2023 who fit the eligibility for rescue kidneys. Rescue kidney eligibility was defined as recipients who had an eGFR≤20ml/min, CrCl≤20ml/min, or were receiving chronic dialysis at any point 60-365 days post-transplant. Baseline characteristics and survival out to 1 and 3 years were evaluated for the rescue kidney-eligible cohort compared to all other lung transplant recipients in the study period.

RESULTS

Five hundred and fifty four (2.1%) of all recipients would have been eligible for a rescue kidney under the new policy. Comparing to non-eligible group, they were older (median, 62 vs 61 years; p < 0.001), had higher body mass index (BMI) (27 vs 26; p < 0.001), and were more often Black (13% vs 9%; p < 0.001). They also had a significantly higher proportion of renal dysfunction (including chronic kidney disease [CKD] stage III, IV and V) at the time of transplant (17% vs 7%; p < 0.001) and higher likelihood of pre-transplant dialysis (7% vs 0%; p < 0.001). The rescue-eligible recipients had higher rates of life support (14% vs 11%; p = 0.031) and greater lung allocation score (LAS) at transplant (median 40 vs 39; p < 0.01). Compared to non-eligible recipients, rescue kidney-eligible recipients had lower survival at 1 year (42% vs. 88%, p < 0.001) and 3 years (28% vs. 71%, p < 0.001). These differences in mortality risk persisted after adjusting for donor and recipient characteristics (1-year mortality aHR 9.27; 95% CI 8.16-10.55; p < 0.001; 3-year aHR 5.55; 95% CI 4.97-6.20; p < 0.001).

CONCLUSION

While relatively few recipients would have been eligible for a rescue kidney under the new policy, they had significantly worse survival than non-eligible recipients. This underscores the severe illness of these patients and the importance of assessing whether rescue kidneys can reduce these mortality differences.

Association Factors of Self-Management Behaviour Among Lung Transplant Recipients Based on Health Belief Model: A Cross-Sectional Study

BACKGROUND/OBJECTIVES

Effective self-management after lung transplantation is critical. The Health Belief Model is frequently used to predict and explain the health behaviour in chronic ill patients. The purpose of this study was to explore the status and association factors of self-management among lung transplantation recipients based on the Health Belief Model.

METHODS

A questionnaire survey was conducted on 123 lung transplantation recipients at the lung transplant unit of a general hospital from March 2022 to October 2023. The survey instruments included the Perceived Social Support Scale, the Champion Health Beliefs Model Scale, and the Self-Management Questionnaire for Lung Transplant Recipients. SPSS 25.0 was adopted to perform descriptive statistics, univariate analysis, and multivariate regression analysis.

RESULTS

Scoring indicators of self-management dimensions in lung transplantation recipients were lifestyle management (82.8%), communication with physicians (50.0%), cognitive symptom management (36.0%), and exercise (21.7%). Multiple linear regression analysis showed that the number of postoperative complications, perceived seriousness, perceived benefits, and health motivation explained 22.3% of the total variation in the exercise dimension; health motivation and social support explained 13.5% and 17.4% of the variation in cognitive symptom management dimension and communication with physicians dimension, respectively; and health motivation, social support, and perceived barriers explained 24.0% of the total variation in the lifestyle management dimension.

CONCLUSIONS

Health motivation, perceived seriousness, perceived benefits and barriers, social support, and the number of postoperative complications were the main association factors of self-management behaviour among lung transplant recipients.

Targeted therapy for idiopathic pulmonary fibrosis: a bibliometric analysis of 2004-2024

Background

Idiopathic pulmonary fibrosis (IPF) is a progressive and irreversible interstitial lung disease characterized by high mortality rates. An expanding body of evidence highlights the critical role of targeted therapies in the management of IPF. Nevertheless, there is a paucity of bibliometric studies that have comprehensively assessed this domain. This study seeks to examine global literature production and research trends related to targeted therapies for IPF.

Method

A literature search was conducted using the Web of Science Core Collection, encompassing publications from 2004 to 2024, focusing on targeted therapies for IPF. The bibliometric analysis utilized tools such as VOSviewer, CiteSpace, and the "bibliometrix" package in R.

Results

A total of 2,779 papers were included in the analysis, demonstrating a general trend of continuous growth in the number of publications over time. The United States contributed the highest number of publications, totaling 1,052, while France achieved the highest average citation rate at 75.74. The University of Michigan Medical School was the leading institution in terms of publication output, with 88 papers. Principal Investigator Naftali Kaminski was identified as the most prolific researcher in the field. The American Journal of Respiratory Cell and Molecular Biology emerged as the journal with the highest number of publications, featuring 98 articles. In recent years, the research has emerged surrounding targeted therapies for IPF, particularly focusing on agents such as TGF-β, pathogenesis, and autotaxin inhibitor.

Conclusion

In this bibliometric study, we systematically analyze research trends related to targeted therapies for IPF, elucidating recent research frontiers and emerging directions. The selected keywords-idiopathic pulmonary fibrosis, targeted therapy, bibliometric analysis, transforming growth factor β, and autotaxin inhibitor-capture the essential aspects of this research domain. This analysis serves as a reference point for future investigations into targeted therapies.

Chronic Lung Allograft Dysfunction: Clinical Manifestations and Immunologic Mechanisms

The term "chronic lung allograft dysfunction" has emerged to describe the clinical syndrome of progressive, largely irreversible dysfunction of pulmonary allografts. This umbrella term comprises 2 major clinical phenotypes: bronchiolitis obliterans syndrome and restrictive allograft syndrome. Here, we discuss the clinical manifestations, diagnostic challenges, and potential therapeutic avenues to address this major barrier to improved long-term outcomes. In addition, we review the immunologic mechanisms thought to propagate each phenotype of chronic lung allograft dysfunction, discuss the various models used to study this process, describe potential therapeutic targets, and identify key unknowns that must be evaluated by future research strategies.

Extracorporeal membrane oxygenation vs cardiopulmonary bypass in lung transplantation: an updated meta-analysis

AIM

This meta-analysis aimed to compare the outcomes of extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass (CPB) in lung transplantation.

METHODS

We searched PubMed, Embase, and Cochrane databases for studies comparing ECMO to CPB in lung transplantation. Odds ratios (ORs) for binary endpoints and mean differences (MDs) for continuous outcomes were calculated with 95% confidence intervals (CIs). DerSimonian and Laird random-effects model was applied for all endpoints. I2 statistics was used to assess heterogeneity.

RESULTS

Fourteen studies with a total of 1797 patients were included. ECMO was associated with significant reductions in hepatic dysfunction (OR 0.47, 95% CI 0.25-0.90), hemodialysis (OR 0.62, 95% CI 0.43-0.88), severe graft rejection (OR 0.43, 95% CI 0.23-0.78), one-year mortality (OR 0.70; 95% CI 0.51 to 0.98; p = 0.04; I2 = 13%) and tracheostomy rates (OR 0.62, 95% CI 0.46-0.86). Additionally, ECMO reduced the length of hospital stay (MD - 5.69 days, 95% CI - 9.31 to - 2.08) and ICU stay (MD - 6.02 days, 95% CI - 8.32 to - 3.71). However, ECMO was associated with longer total ischemic time (MD 61.07 min, 95% CI 3.51 to 118.62). No significant differences were observed for stroke, thromboembolic events, atrial fibrillation, or 30-day and 3-year mortality.

CONCLUSIONS

ECMO offers perioperative advantages in lung transplantation, reducing postoperative complications, one-year mortality, and recovery time compared to CPB. However, the longer total ischemic time with ECMO warrants further investigation into its long-term outcomes.

TRIAL REGISTRY

International Prospective Register of Systematic Reviews; N°: CRD42024604049; URL: https://www.crd.york.ac.uk/prospero/ .

Differentially expressed microRNAs in pre-transplant lung biopsies target immune checkpoint proteins and can predict primary graft dysfunction in lung transplantation

Lung transplantation (LTx) significantly improves outcomes for patients with end-stage respiratory failure. However, primary graft dysfunction (PGD) remains one of the most relevant hurdles. Although PGD is attributed to ischemia-reperfusion injury (IRI), immune responses, primarily T cell-mediated, may play a pivotal role in its pathogenesis. Additionally, innate immune activation following IRI links PGD to adaptive alloimmunity, highlighting the impact of early events on LTx outcomes. Immune checkpoints (ICPs) such as PD-1/PD-L1, CD40/CD40LG, and OX40/OX40L, regulate post-LTx T cell responses, and dysregulation of microRNAs (miRNAs) has been implicated in altering ICP expression, influencing the amplification of immune responses. In this preliminary study, we used the taqMan low-density array (TLDA) cards to investigate miRNA dysregulation's prognostic potential as a PGD marker in pre-transplant back-table lung biopsies. Our analysis revealed differential miRNA expression in donor lung tissues, potentially associated with PGD onset, targeting immune regulatory pathways. Specifically, deregulated miRNAs targeted key ICP proteins, including PD-L1, CD40LG, and OX40L. Moreover, the differential expression of these miRNAs was observed in grafts with future PGD compared to grafts without PGD, suggesting a potential prognostic benefit and a possible role for lung tissue miRNAs in the onset of early graft dysfunction. These findings provide a basis for future investigations into their mechanistic roles and therapeutic potential for PGD. Although based on a limited number of cases, our results imply that miRNAs might be involved in early graft dysfunction. While requiring validation in larger cohorts, our data raise the possibility that the evaluation of the aforementioned markers during the pre-transplant phase, might offer a prognostic benefit in monitoring the onset of PGD. Additionally, the use of compounds that can modulate the function of these molecules could be evaluated for the management of LTx patients.

Activation of Nrf2 pathway by 4-Octyl itaconate enhances donor lung function in cold preservation settings

BACKGROUND

Lung transplantation is the primary treatment for end-stage lung diseases. However, ischemia-reperfusion injury (IRI) significantly impacts transplant outcomes. 4-Octyl itaconate (4-OI) has shown potential in mitigating organ IRI, although its effects in lung transplantation require further exploration.

METHODS

BEAS-2B cells were used to model transplantation, assessing the effects of 4-OI through viability, apoptosis, and ROS assays. qRT-PCR analyzed cytokine transcription post-cold ischemia/reperfusion (CI/R). RNA sequencing and Gene Ontology analysis elucidated 4-OI's mechanisms of action, confirmed by Western blotting. ALI-airway and lung transplantation organoid models evaluated improvements in bronchial epithelial morphology and function due to 4-OI. ELISA measured IL-6 and IL-8 levels. Rat models of extended cold preservation and non-heart-beating transplantation assessed 4-OI's impact on lung function, injury, and inflammation.

RESULTS

Our findings indicate that 4-OI (100 µM) during cold preservation effectively maintained cell viability, decreased apoptosis, and reduced ROS production in BEAS-2B cells under CI/R conditions. It also downregulated pro-inflammatory cytokine transcription, including IL1B, IL6, and TNF. Inhibition of Nrf2 partially reversed these protective effects. In cold preservation solutions, 4-OI upregulated Nrf2 target genes such as NQO1, HMOX1, and SLC7A11. In ALI airway models, 4-OI enhanced bronchial epithelial barrier integrity and ciliary beat function after CI/R. In rat models, 4-OI administration improved lung function and reduced pulmonary edema, tissue injury, apoptosis, and systemic inflammation following extended cold preservation or non-heart-beating lung transplantation.

CONCLUSIONS

Incorporating 4-OI into cold preservation solutions appears promising for alleviating CI/R-induced bronchial epithelial injury and enhancing lung transplant outcomes via Nrf2 pathway activation.

Human respiratory airway progenitors derived from pluripotent cells generate alveolar epithelial cells and model pulmonary fibrosis

Human lungs contain unique cell populations in distal respiratory airways or terminal and respiratory bronchioles (RA/TRBs) that accumulate in persons with lung injury and idiopathic pulmonary fibrosis (IPF), a lethal lung disease. As these populations are absent in rodents, deeper understanding requires a human in vitro model. Here we convert human pluripotent stem cells (hPS cells) into expandable spheres, called induced respiratory airway progenitors (iRAPs), consisting of ~98% RA/TRB-associated cell types. One hPS cell can give rise to 1010 iRAP cells. We differentiate iRAPs through a stage consistent with transitional type 2 alveolar epithelial (AT2) cells into a population corresponding to mature AT1 cells with 95% purity. iRAPs with deletion of Heřmanský-Pudlák Syndrome 1 (HPS1), which causes pulmonary fibrosis in humans, replicate the aberrant differentiation and recruitment of profibrotic fibroblasts observed in IPF, indicating that intrinsic dysfunction of RA/TRB-associated alveolar progenitors contributes to HPS1-related IPF. iRAPs may provide a system suitable for IPF drug discovery and validation.

Beyond the Graft: Recurrence of Interstitial Lung Diseases Post Transplant

Interstitial lung diseases (ILDs) represent a heterogenous group of lung disorders marked by inflammation and/or fibrosis of the lung parenchyma, often leading to progressive shortness of breath and end-stage respiratory failure. In the U.S., ILDs affect approximately 650,000 individuals and cause approximately 25,000-30,000 deaths annually. Lung transplantation (LTx) offers definitive treatment for advanced ILD, with improved survival attributed to advancements in immunosuppression, organ preservation, surgical techniques, and postoperative care. However, disease recurrence in transplanted lungs remains a significant concern. Understanding the risk factors and mechanisms underlying recurrence is critical for refining recipient selection and improving outcomes. This review examines ILD recurrence post LTx and its implications for lung transplantation success.

Lung transplantation for pulmonary chronic graft-versus-host disease: a missed opportunity?

Chronic graft-versus-host disease is a common complication after allogeneic hematopoietic stem cell transplantation, with pulmonary chronic graft-versus-host disease (PcGvHD) particularly associated with a dismal prognosis. Lung transplantation (LuTx) is a final therapeutic option for well-selected patients affected by this condition. Nevertheless, only a small group of PcGvHD patients are referred for LuTx. This review addresses common concerns regarding referral and listing of PcGvHD patients for LuTx (such as risk of relapse of hematological malignancy, infectious complications and rejection) and survival outcomes of this specific cohort of patients. Importantly, LuTx for PcGvHD has comparable outcomes to other indications. The establishment of specific LuTx indication criteria for PcGvHD patients may improve referral rates and timing of both referral and listing of suitable candidates.

Survival in Patients With Evidence of Pulmonary Thromboembolism on Ventilation-Perfusion SPECT 12 Weeks After Double Lung Transplantation: A Retrospective Cohort Study

BACKGROUND

Patients who have undergone double lung transplantation (DLTx) are at increased risk of pulmonary thromboembolism (PTE). Although the presence of clinically overt PTE can adversely affect short-term mortality, the prognostic impact of asymptomatic (silent) PTE detected by routine imaging after DLTx is unclear. This study aimed to determine whether PTE identified by routine ventilation-perfusion single-photon emission computed tomography (V̇-Q̇ SPECT) 12 weeks post-DLTx is associated with subsequent all-cause and graft-related mortality.

METHODS

Single-center retrospective cohort study evaluating 130 DLTx recipients who underwent routine V̇-Q̇ SPECT imaging 12 weeks posttransplant between 2012 and 2017. V̇-Q̇ SPECT scans were assessed for perfusion and ventilation defects indicative of PTE. The association between PTE and mortality outcomes was analyzed using multivariable Cox regression, Kaplan-Meier survival curves, and cumulative incidence functions.

RESULTS

PTE was identified in 24.6% (n = 32) of the patients 12 weeks post-DLTx. After 3 months of follow-up, there was no detectable difference in lung function between patients with and without PTE. Moreover, the presence of PTE was not associated with increased hazard ratios for all-cause mortality (HR = 0.72; 95% CI: 0.37-1.41; p = 0.34) or graft-specific mortality (HR = 0.95; 95% CI: 0.42-2.16; p = 0.91).

CONCLUSIONS

PTE is a frequent finding on routine V̇-Q̇ SPECT 12 weeks post-DLTx that does not inform risk of all-cause or graft-related mortality. These findings suggest that an incidentally detected PTE in asymptomatic patients may not necessitate changes in clinical management for asymptomatic DLTx patients.

[Long-COVID, severe course, with congenital bronchiectasis, Williams-Campbell syndrome. Case report]

We present a clinical observation of an 18-year-old female patient with congenital bronchiectasis combined with congenital cystic degeneration of the upper lobes of both lungs, Williams-Campbell syndrome, long-COVID, severe course. The patient was treated in infectious disease department (three times), with subsequent transfer to pulmonology department of Kursk Regional Multi-Purpose Clinical Hospital from 31.01.2023 to 02.05.2023. The patient was going to have lung transplantation, registered in Shumakov Federal Research Center of Transplantology and Artificial Organs earlier. The patient was transported by air ambulance escorted by the resuscitation team to the Shumakov Federal Research Center of Transplantology and Artificial Organs on 02.05.2023 with negative PCR COVID-19 test. The literature data on the frequency of association of these diseases, clinical features, criteria for diagnosis and treatment, indications for lung transplantation are presented.

Racial Equity in Family Approach for Patients Medically Suitable for Deceased Organ Donation

OBJECTIVES

To conduct a contemporary analysis of the association between family approach of medically suitable potential organ donors and race/ethnicity.

DESIGN

Retrospective review of data collected prospectively by Organ Procurement Organizations (OPOs).

SETTING

Ten OPOs representing eight regions of the Organ Procurement and Transplantation Network and 26% of all deceased donor organs recovered in the United States.

SUBJECTS

All hospitalized patients on mechanical ventilation and referred to OPOs as potential donors from January 1, 2018, to December 31, 2022.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

OPOs provided data on referral year, race, sex, donor registration status, screening determination, donation medical suitability, donation type (brain death, circulatory death), and family approach. We evaluated factors associated with family approach to discuss donation using descriptive statistics and multivariable logistic models. Of 255,429 total cases, 138,622 (54%) were screened-in for further evaluation, with variation by race/ethnicity (50% White, 60% Black, 69% Hispanic, and 60% Asian). Among those screened-in, 31,253 (23%) were medically suitable for donation, with modest variation by race/ethnicity (22% White, 26% Black, 23% Hispanic, and 21% Asian). Family approach rate by OPOs of medically suitable cases was 94% ( n = 29,315), which did not vary by race/ethnicity (94% White, 93% Black, 95% Hispanic, and 95% Asian). Family approach by OPOs was lower for circulatory death (95%) vs. brain death (97%) cases but showed minimal differences in approach rate based on race/ethnicity between medically suitable patients with different death pathways. In contrast, donor registration status of medically suitable potential donors was highly variable by race/ethnicity (37% overall; 45% White, 21% Black, 29% Hispanic, and 25% Asian). Multivariable models indicated no significant difference of family approach between White and Black (odds ratio [OR], 1.09; 95% CI, 0.95-1.24) or Asian (OR, 1.23; 95% CI, 0.95-1.60) patients.

CONCLUSIONS

Findings indicate racial equity in OPO family approach rates among patients who were medically suitable for organ donation.

Current status of routine use of veno-arterial extracorporeal membrane oxygenation during lung transplantation

INTRODUCTION

Recently, there has been growing experience with utilizing a veno-arterial extracorporeal membrane oxygenator (VA ECMO) routinely during lung transplantation procedures. Yet, there is a lack of consensus on the protocols, benefits, and outcomes of routine VA ECMO use in lung transplantation.

AREAS COVERED

This article presents an overview of the current status of routine use of VA ECMO during lung transplantation, including rationale, protocols, applications, and outcomes.

EXPERT OPINION

Utilization of VA ECMO during lung transplantation has emerged as an alternative mechanical circulatory support modality to cardiopulmonary bypass, with growing evidence showing lower rates of peri-operative complications. Some groups took that further into routine application of VA ECMO during lung transplantation. The current available evidence suggests that routine utilization of VA ECMO during lung transplantation is associated with lower rates of primary graft dysfunction and improved early outcomes. Use of VA ECMO allows controlled reperfusion of the allograft and avoids an unplanned "crash" on pump in case of hemodynamic instability, which carries worse outcomes after lung transplantation. As a relatively new approach, further follow-up of growing experience, as well as prospective clinical trials, is necessary to develop a consensus about routine utilization of VA ECMO during lung transplantation.

Decoding the hallmarks of allograft dysfunction with a comprehensive pan-organ transcriptomic atlas

The pathogenesis of allograft (dys)function has been increasingly studied using 'omics'-based technologies, but the focus on individual organs has created knowledge gaps that neither unify nor distinguish pathological mechanisms across allografts. Here we present a comprehensive study of human pan-organ allograft dysfunction, analyzing 150 datasets with more than 12,000 samples across four commonly transplanted solid organs (heart, lung, liver and kidney, n = 1,160, 1,241, 1,216 and 8,853 samples, respectively) that we leveraged to explore transcriptomic differences among allograft dysfunction (delayed graft function, acute rejection and fibrosis), tolerance and stable graft function. We identified genes that correlated robustly with allograft dysfunction across heart, lung, liver and kidney transplantation. Furthermore, we developed a transfer learning omics prediction framework that, by borrowing information across organs, demonstrated superior classifications compared to models trained on single organs. These findings were validated using a single-center prospective kidney transplant cohort study (a collective 329 samples across two timepoints), providing insights supporting the potential clinical utility of our approach. Our study establishes the capacity for machine learning models to learn across organs and presents a transcriptomic transplant resource that can be employed to develop pan-organ biomarkers of allograft dysfunction.

Experimental Lung Transplantation Related With HIF-1, VEGF, ROS. Assessment of HIF-1alpha, VEGF, and Reactive Oxygen Species After Competitive Blockade of Chetomin for Lung Transplantation in Rats

Primary graft failure occurs 15 to 30 % of the time after transplantation. Although there have been improvements in preserving the lungs in good condition, there have not been studies on the regulation of transcription factors.

METHODS

We carried out an experimental study involving lung transplantation to indirectly evaluate reactive oxygen species (ROS) production and VEGF expression by competitive blockade of HIF-1alpha with chetomin. There were 5 groups: Group-1: Lung blocks were perfused with 0.9 % SSF, immediately harvested, and preserved. Group-2 (I-T): Immediate transplantation and then reperfusion for 1 h. Group-3 (I-R): Lung blocks were harvested and preserved in LPD solution for 6 h and reperfused for 1 h. Group-4 (DMSO): Lung blocks were treated for 4 h with DMSO, preserved for 6 h and transplanted to a receptor treated with DMSO. Group-5 (chetomin): Lung blocks were treated for 4 h with chetomin, preserved for 6 h and transplanted to a receptor treated with chetomin. ROS, mRNA, and protein levels of HIF-1alpha and EG-VEGF were determined.

RESULTS

The DMSO and chetomin groups had significantly lower ROS levels. Compared with those in the I-R group, the chetomin group exhibited the lowest level of HIF-1alpha.

CONCLUSIONS

Addition of chetomin to the donor and the receptor results in a significant reduction in HIF-1A, VEGF and ROS.

Clinical significance and potential mechanism of hsa_circ_0006892 in acute respiratory distress syndrome complicated with pulmonary fibrosis

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a serious acute lung injury, and can develop into pulmonary fibrosis (PLF). Circular RNAs (circRNAs) regulatory network in ARDS is important. The study explored the role of hsa_circ_0006892 in the occurrence of ARDS and the development of PLF.

METHODS

Hsa_circ_0006892 levels were verified in serum samples of 203 ARDS patients with or without PLF, and the diagnostic value was evaluated through ROC. Cox regression analysis was performed to identify PLF-related factors. The downstream target genes were predicted online. The function and pathway of key genes were annotated through GO and KEGG pathway analysis. Protein-protein interaction (PPI) analysis was performed for the examination of protein interactions.

RESULTS

qRT-PCR determined the downregulation of hsa_circ_0006892 in the serum of both ARDS and PLF patients. Hsa_circ_0006892 can differentiate ARDS from controls, and independently related to the development of PLF. Nine targeted related miRNAs were integrated with dysregulated miRNAs from GSE27430 dataset. Clinically, miR-486-3p was the only miRNA that was significantly different in both ARDS and PLF groups, and was determined to be the target of hsa_circ_0006892. 180 target genes of miR-486-3p were predicted, which were integrated with ARDS and PLF-related GSE84439 and GSE38958 datasets. Go and KEGG pathway analysis identified Ras signaling pathway as the most commonly enriched pathway in the overlapped genes.

CONCLUSIONS

The present results identified the differentially expressed hsa_circ_0006892 in ARDS and PLF, and suggested a possible molecular mechanism of hsa_circ_0006892/miR-486-3p axis.

Murine orthotopic lung transplant models: A comprehensive overview of genetic mismatch degrees and histopathological insights into chronic lung allograft dysfunction

Currently, lung transplantation outcome remains inferior compared to other solid organ transplantations. A major cause for limited survival after lung transplantation is chronic lung allograft dysfunction. Numerous animal models have been developed to investigate chronic lung allograft dysfunction to discover adequate treatments. The murine orthotopic lung transplant model has been further optimized over the last years. However, different degrees of genetic mismatch between donor and recipient mice have been used, applying a single, minor, moderate, and major genetic mismatch. This review aims to reassess the existing murine mismatch models and provide a comprehensive overview, with a specific focus on their eventual histopathological presentation. This will be crucial to leverage this model and tailor it according to specific research needs.

Impact of reduced mycophenolate exposure on chronic lung allograft dysfunction incidence after lung transplant

Background

Mycophenolate mofetil (MMF) is a key immunosuppression agent for lung transplant recipients (LTR); however, the side effects often lead to dose modifications. Kidney transplant literature has shown reductions in MMF dosing led to an increased incidence of rejection, but data are limited in LTR. The objective was to evaluate the impact of reduced MMF exposure on chronic lung allograft dysfunction (CLAD) in LTR within 36 months of transplant (TXP).

Methods

This single-center, retrospective cohort analyzed LTRs who had an MMF dose reduction or hold ≥7 days between April 1, 2016 and October 31, 2019. LTR who died ≤1 month from TXP were excluded. The primary outcome was incidence of CLAD 36 months from TXP compared to the International Society for Heart and Lung Transplantation (ISHLT) registry data. Secondary outcomes were incidence of treated acute cellular rejection and characterization of MMF dose modifications.

Results

Of 109 patients evaluated, 102 (93.6%) patients had 194 MMF dose modifications within 36 months of TXP, largely due to hematologic toxicities (74.7%). Before modification, 142 (73.2%) were receiving MMF 1,000 mg/day and 52 (26.8%) were receiving 500 mg/day. Incidence of CLAD was 36.4% at 36 months compared to 32.6% reported by ISHLT (p = 0.5216). Incidence of patients with decline in forced expiratory volume in 1 sec ≥10% was 45.1% at 36 months.

Conclusions

In our cohort, most LTRs had an MMF dose modification within 36 months, yet CLAD incidence was consistent with rates reported in the ISHLT Thoracic Organ Transplant Registry. In contrast, more patients demonstrated reduced allograft function compared to post-TXP peak, consistent with "potential" CLAD.

Donor-Specific Blood Transfusion in Lung Transplantation

Lung transplantation is still hindered by a high rate of chronic rejection necessitating profound immunosuppression with its associated complications. Donor-specific blood transfusion is a pre-transplant strategy aimed at improving graft acceptance. In contrast with standard stored blood or donor-specific regulatory T cells transfusions, this approach utilizes fresh whole blood from the donor prior to allograft transplantation, encompassing all cell types and plasma. The precise mechanisms underlying donor-specific blood transfusion-induced tolerance remain incompletely understood. Associations with regulatory/helper T cells, modulation of mononuclear phagocytic cells or microchimerism have been suggested. While numerous (pre-)clinical studies have explored its application in solid organ transplants like liver, kidney, and intestine, limited attention has been given to the setting of lung transplantation. This comprehensive review summarizes existing knowledge on the mechanisms and outcomes of donor-specific blood transfusion in solid organ transplants both in preclinical and clinical settings. We also address the potential benefits and risks associated with donor-specific blood transfusion in the field of lung transplantation, offering insights into future research directions.

Cold ischemia time alters cell-type specific senescence leading to loss of cellular integrity in mouse lungs

Purpose: Ischemia-reperfusion injury (IRI) is a major challenge in lung transplantation often causing graft dysfunction and chronic airway illnesses in recipients. To prevent potential transplant related complications, strict guidelines were put in place to choose viable donor lungs with minimal risk of IRI. These regulations deem most of the donor organs unfit for transplant which then are donated for research to understand the mechanisms of health and diseases in human. However, resected organs that are being transported undergo cold ischemia that can negatively affect the tissue architecture and other cellular functions under study. Thus, it is important to assess how cold ischemia time (CIT) affects the physiological mechanism. In this respect, we are interested in studying how CIT affects cellular senescence in normal aging and various pulmonary pathologies. We thus hypothesized that prolonged CIT exhibits cell-type specific changes in lung cellular senescence in mice. Methods: Lung lobes from C57BL/6J (n = 5-8) mice were harvested and stored in UW Belzer cold storage solution for 0, 4-, 9-, 12-, 24-, and 48-h CIT. Lung cellular senescence was determined using fluorescence (C12FdG) assay and co-immunolabelling was performed to identify changes in individual cell types. Results: We found a rapid decline in the overall lung cellular senescence after 4-h of CIT in our study. Co-immunolabelling revealed the endothelial cells to be most affected by cold ischemia, demonstrating significant decrease in the endothelial cell senescence immediately after harvest. Annexin V-PI staining further revealed a prominent increase in the number of necrotic cells at 4-h CIT, thus suggesting that most of the cells undergo cell death within a few hours of cold ischemic injury. Conclusions: We thus concluded that CIT significantly lowers the cellular senescence in lung tissues and must be considered as a confounding factor for mechanistic studies in the future.

Venopulmonary extracorporeal membrane oxygenation for right ventricular support as a bridge to lung transplantation: A narrative review

This review evaluates the effectiveness of veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation as a bridge to lung transplantation strategy in patients undergoing veno-venous extracorporeal membrane oxygenation while awaiting lung transplantation. Examining indications, contraindications, and clinical outcomes, the study highlights potential benefits, drawing insights from successful cases in South Korea and the United States. Despite limited sample sizes, veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation emerges as a promising approach for further investigation in lung transplantation support. The review emphasizes its role in improving hemodynamic status, preventing complications during extended waiting periods, and presenting a cost-effective alternative to traditional methods, especially in developing countries. While in-hospital mortality rates range from 0% to 10%, comparable to other approaches, cautious optimism surrounds veno-pulmonary support with an oxygenator using extracorporeal membrane oxygenation, urging expanded research to solidify its standing in enhancing patient outcomes, reducing costs, and promoting transplant success.

Donor age over 55 is associated with worse outcome in lung transplant recipients with idiopathic pulmonary fibrosis

BACKGROUND

Lung transplantation (LTx) remains the only efficient treatment for selected patients with end-stage pulmonary disease. The age limit for the acceptance of donor organs in LTx is still a matter of debate. We here analyze the impact of donor organ age and the underlying pulmonary disease on short- and long-term outcome and survival after LTx.

METHODS

Donor and recipient characteristics of LTx recipients at our institution between 03/2003 and 12/2021 were analyzed. Statistical analysis was performed using SPSS and GraphPad software.

RESULTS

In 230 patients analyzed, donor age ≥ 55 years was associated with a higher incidence of severe primary graft dysfunction (PGD2/3) (46% vs. 31%, p = 0.03) and reduced long-term survival after LTx (1-, 5- and 10-year survival: 75%, 54%, 37% vs. 84%, 76%, 69%, p = 0.006). Notably, this was only significant in recipients with idiopathic pulmonary fibrosis (IPF) (PGD: 65%, vs. 37%, p = 0.016; 1-, 5-, and 10-year survival: 62%, 38%, 16% vs. 80%, 76%, 70%, p = 0.0002 respectively). In patients with chronic obstructive pulmonary disease (COPD), donor age had no impact on the incidence of PGD2/3 or survival (21% vs. 27%, p = 0.60 and 68% vs. 72%; p = 0.90 respectively). Moreover, we found higher Torque-teno virus (TTV)-DNA levels after LTx in patients with IPF compared to COPD (X2 = 4.57, p = 0.033). Donor age ≥ 55 is an independent risk factor for reduced survival in the whole cohort and patients with IPF specifically.

CONCLUSIONS

In recipients with IPF, donor organ age ≥ 55 years was associated with a higher incidence of PGD2/3 and reduced survival after LTx. The underlying pulmonary disease may thus be a relevant factor for postoperative graft function and survival.

TRIAL REGISTRATION NUMBER DKRS

DRKS00033312.

Association between Respiratory Virus Infection and Development of De Novo Donor-Specific Antibody in Lung Transplant Recipients

Chronic lung allograft dysfunction (CLAD) is the most common cause of long-term lung allograft failure. Several factors, including respiratory virus infection (RVI), have been associated with CLAD development, but the underlying mechanisms of these associations are not well understood. We hypothesize that RVI in lung transplant recipients elicits the development of donor-specific antibodies (DSAs), thus providing a mechanistic link between RVI and CLAD development. To test this hypothesis, we retrospectively evaluated for the presence of HLA antibodies in a cohort of lung transplant recipients with symptomatic RVI within the first four months post-transplant using sera at two time points (at/directly after the transplant and following RVI) and time-matched controls without RVI (post-transplant). We found a trend toward the development of de novo DSAs in those with symptomatic RVI versus controls [6/21 (29%) vs. 1/21 (5%), respectively, p = 0.09]. No cases or controls had DSA at baseline. We also found increased rates of CLAD and death among those who developed class II DSA versus those who did not (CLAD: 5/7 (71.4%) vs. 19/34 (54.3%), death: 5/7 (71.4%) vs. 17/35 (48.6%)). Prospective studies evaluating the temporal development of DSA after RVI in lung transplant patients and the subsequent outcomes are warranted.

Preconditioning with β-hydroxybutyrate attenuates lung ischemia-reperfusion injury by suppressing alveolar macrophage pyroptosis through the SIRT1-FOXO3 signaling pathway

The complex pathogenesis of lung ischemia-reperfusion injury (LIRI) was examined in a murine model, focusing on the role of pyroptosis and its exacerbation of lung injury. We specifically examined the levels and cellular localization of pyroptosis within the lung, which revealed alveolar macrophages as the primary site. The inhibition of pyroptosis by VX-765 reduced the severity of lung injury, underscoring its significant role in LIRI. Furthermore, the therapeutic potential of β-hydroxybutyrate (β-OHB) in ameliorating LIRI was examined. Modulation of β-OHB levels was evaluated by ketone ester supplementation and 3-hydroxybutyrate dehydrogenase 1 (BDH-1) gene knockout, along with the manipulation of the SIRT1-FOXO3 signaling pathway using EX-527 and pCMV-SIRT1 plasmid transfection. This revealed that β-OHB exerts lung-protective and anti-pyroptotic effects, which were mediated through the upregulation of SIRT1 and the enhancement of FOXO3 deacetylation, leading to decreased pyroptosis markers and lung injury. In addition, β-OHB treatment of MH-S cells in vitro showed a concentration-dependent improvement in pyroptosis, linking its therapeutic benefits to specific cell mechanisms. Overall, this study highlights the significance of alveolar macrophage pyroptosis in the exacerbation of LIRI and indicates the potential of β-OHB in mitigating injury by modulating the SIRT1-FOXO3 signaling pathway.

The application of ERAS in the perioperative period management of patients for lung transplantation

Objective

To explore the application of enhanced recovery after surgery (ERAS) in the perioperative period of lung transplantation.

Methods

We retrospectively collected the clinical data of 27 lung transplant patients who underwent ERAS during the perioperative period, while 12 lung transplant patients receiving routine treatment served as controls. General information was collected, including the specific implementation plan of ERAS, the incidence of complications and survival rate during the perioperative period (<30 d), postoperative hospitalization indicators, the postoperative length of stay, and numerical rating scale (NRS) scores.

Results

Comparison of postoperative hospitalization indicators, the ERAS group compared with the control group, there were significant differences in postoperative ICU stay time (2.0(2.0,4.0) vs 4.5(3.0,6.0), p = 0.005), postoperative hospital stay time (18(15,26) vs 24(19.5,32.75), p = 0.016), duration of nasogastric tube (3(2,3) vs 4(2.25,4.75), p = 0.023), and first ambulation time (4(3,5) vs 5.8(4.5,7.5), p = 0.004). There was no significant difference in postoperative invasive mechanical ventilation time, time to eat after surgery, duration of urinary catheter and duration of chest tube between the ERAS group and the control group (p>0.05). The perioperative survival of the ERAS group was 81.5%, which was higher than the control group (66.7%), but there is no statistically significant difference. Comparison of post-extubation NRS scores, the ERAS group had lower NRS scores at 12 h (5.30 ± 0.14 vs 6.25 ± 0.75), 24 h (3.44 ± 0.64 vs 5.58 ± 0.9), 48 h (2.74 ± 0.66 vs 4.08 ± 0.79) and 72 h (1.11 ± 0.80 vs 2.33 ± 0.49) than the control group, the difference was statistically significant (p<0.01). Intra-group comparison, post-extubation 12 h comparison post-extubation 24 h, 48 h, 72 h, the NRS scores showed a gradual downward trend, the difference was statistically significant (p<0.01). In the comparison of perioperative complications, the ERAS group had a lower postoperative infection incidence than the control group, the difference was statistically significant (44.4% vs 83.3%, p = 0.037). The ERAS group had lower postoperative delirium incidence than the control group, the difference was statistically significant (11.1% vs 50%, p = 0.014). There was no significant difference in the incidence of acute rejection, primary graft loss (PGD), gastrointestinal (GI) complications and airway complications between two groups (p>0.05).

Conclusion

The ERAS can be applied to lung transplant patients to relieve postoperative pain, shorten postoperative tube time, and shorten postoperative stay. Perioperative pulmonary rehabilitation exercises are beneficial to reducing the occurrence of postoperative pulmonary complications.

Mitigating the risk of inflammatory type primary graft dysfunction by applying an integrated approach to assess, modify and match risk factors in lung transplantation

Long-term outcome following lung transplantation remains one of the poorest of all solid organ transplants with a 1- and 5-year survival of 85% and 59% respectively for adult lung transplant recipients and with 50% of patients developing chronic lung allograft dysfunction (CLAD) in the first 5 years following transplant. Reducing the risk of inflammatory type primary graft dysfunction (PGD) is vital for improving both short-term survival following lung transplantation and long-term outcome due to the association of early inflammatory-mediated damage to the allograft and the risk of CLAD. PGD has a multifactorial aetiology and high-grade inflammatory-type PGD is the result of cumulative insults that may be incurred in one or more of the three variables of the transplantation continuum: the donor lungs, the recipient and intraoperative process. We set out a conceptual framework which uses a fully integrated approach to this transplant continuum to attempt to identify and, where possible, modify specific donor, recipient and intraoperative PGD risk with the goal of reducing inflammatory-type PGD risk for an individual recipient. We also consider the concept and risk-benefit of matching lung allografts and recipients on the basis of donor and recipient PGD-risk compatibility. The use of ex vivo lung perfusion (EVLP) and the extended preservation of lung allografts on EVLP will be explored as safe, non-injurious EVLP may enable extensive inflammatory testing of specific donor lungs and has the potential to provide a platform for targeted therapeutic interventions on lung allografts.

Lung donor bronchoalveolar lavage positivity: Incidence, risk factors, and lung transplant recipients' outcome

BACKGROUND

Inconsistent data exists regarding the risk factors for bronchoalveolar lavage (BAL) positivity in lung donors, the incidence of donor-derived infections (DDI), and the effect of BAL positivity on lung transplant (LuTx) recipients' outcome.

METHODS

A retrospective analysis was conducted on consecutive LuTx at a single center from January 2016 to December 2022. Donors' data, including characteristics, graft function and BAL samples were collected pre-procurement. Recipients underwent BAL before LuTx and about the 3rd, 7th and 14th day after LuTx. A DDI was defined as BAL positivity (bacterial growth ≥104 colony forming units) for identical bacterial species between donor and recipient. Recipients' pre-operative characteristics, intra-operative management, and post-operative outcomes were assessed. Two recipient cohorts were identified based on lung colonization status before undergoing LuTx.

RESULTS

Out of 188 LuTx procedures performed, 169 were analyzed. Thirty-six percent of donors' BAL tested positive. Donors' characteristics and graft function at procurement were not associated with BAL positivity. Fourteen DDI were detected accounting for 23% of recipients receiving a graft with a positive BAL. Only among uncolonized recipients, receiving a graft with positive BAL is associated with higher likelihood of requiring invasive ventilation at 72 hours after LuTx on higher positive end-expiratory pressure levels having lower PaO2/FiO2, prolonged duration of mechanical ventilation and longer ICU stay. No difference in hospital length of stay was observed.

CONCLUSIONS

Receiving a graft with a positive BAL, which is poorly predicted by donors' characteristics, carries the risk of developing a DDI and is associated to a worse early graft function among uncolonized recipients.

Impact of pre-existing frailty on survival outcomes in solid-organ transplant candidates and recipients: A meta-analysis

BACKGROUND

There is controversy surrounding the association between preexisting frailty and increased mortality in candidates and recipients of solid-organ transplants. This meta-analysis aimed to evaluate the impact of preexisting frailty on survival outcomes in solid-organ transplant candidates and recipients.

METHODS

A systematic search was conducted in the PubMed, Web of Sciences, and Embase databases until October 2, 2023. Two reviewers independently selected the eligible studies according to the PECOS criteria: Participants (candidates and recipients of solid-organ transplants), Exposure (frailty), Comparison (no-frailty), Outcomes (waitlist or posttransplant mortality), and Study design (retrospective or prospective cohort studies). The pooled effects were summarized by pooling the adjusted hazard ratio (HR) with 95 % confidence intervals (CI) for the frail patients than those without frailty.

RESULTS

Sixteen studies with 10091 patients met the eligibility criteria. Depending on the frailty tools used, the prevalence of frailty in solid-organ transplant candidates/recipients ranged from 4.6 % to 45.1 %. Frailty was significantly associated with an increased risk of waitlist mortality (HR 2.44; 95 % CI 1.84-3.24) and posttransplant mortality (HR 2.23; 95 % CI 1.61-3.09) in solid-organ transplant candidates and recipients, respectively. Subgroup analyses showed that the association of preexisting frailty with waitlist mortality and posttransplant mortality appeared to stronger in kidney transplant candidates (HR 2.70; 95 % CI 1.93-3.78) and lung transplantation recipients (HR 2.52; 95 % CI 1.23-5.15).

CONCLUSION

Frailty is a significant predictor of reduced survival in solid-organ transplant candidates and recipients. Assessment of frailty has the potential to identify patients who are suitable for transplantation.

Evaluating longitudinal cytomegalovirus-specific humoral immune responses and association with DNAemia risk in seropositive lung transplant recipients

Background

Cytomegalovirus (CMV) is the most common viral infection among lung transplant recipients and is associated with chronic lung allograft dysfunction. There is a need for better therapeutics as well as biomarkers to enable effective stratification of CMV seropositive patient risk for developing CMV DNAemia to inform prophylaxis duration.

Methods

CMV-specific immunoglobulin G (IgG) binding and functional responses were evaluated in a discovery cohort of longitudinal plasma samples from 51 CMV seropositive human lung transplant recipients, collected as part of the clinical trials in organ transplantation (CTOT)-20 and CTOT-22 consortium studies. Pre-transplant plasma from an additional 43 CMV seropositive lung transplant recipients was evaluated as a validation cohort.

Results

In the discovery cohort with longitudinal samples, pre-transplant plasma IgG binding to CMV surface glycoproteins glycoprotein H (gH)/glycoprotein L (gL), gH/gL/glycoprotein O (gO), and pentameric complex, as well as neutralization of CMV in epithelial cells, is associated with increased risk of CMV DNAemia post-prophylaxis. However, these results were not confirmed by the validation cohort.

Conclusions

While quantification of pre-transplant CMV-specific antibody responses showed association with DNAemia in the discovery cohort, additional clinical variables and/or known risk factors for CMV, such as patient CMV-specific T-cell responses, may need to be considered in combination with humoral immunity to effectively stratify risk of CMV DNAemia.

Chronic Postsurgical Pain Following Lung Transplantation: Characteristics, Risk Factors, Treatment, and Prevention: A Narrative Review

Chronic pain after lung transplantation (LTx) can substantially reduce quality of life (QoL), yet current consensus guidelines say little about how to prevent or manage it. Research on pain after LTx has tended to focus on acute rather than chronic pain, and it has not extensively examined the factors associated with onset or resolution of chronic pain, which differ from factors influencing chronic pain after general thoracic surgery. This narrative review explores what is known about the epidemiology and risk factors of chronic pain after LTx, as well as effective ways to treat or prevent it. The review identifies key questions and issues that should be the focus of future research.

Clinical Deployment of Machine Learning Tools in Transplant Medicine: What Does the Future Hold?

Medical applications of machine learning (ML) have shown promise in analyzing patient data to support clinical decision-making and provide patient-specific outcomes. In transplantation, several applications of ML exist which include pretransplant: patient prioritization, donor-recipient matching, organ allocation, and posttransplant outcomes. Numerous studies have shown the development and utility of ML models, which have the potential to augment transplant medicine. Despite increasing efforts to develop robust ML models for clinical use, very few of these tools are deployed in the healthcare setting. Here, we summarize the current applications of ML in transplant and discuss a potential clinical deployment framework using examples in organ transplantation. We identified that creating an interdisciplinary team, curating a reliable dataset, addressing the barriers to implementation, and understanding current clinical evaluation models could help in deploying ML models into the transplant clinic setting.

The impact of bleeding on outcomes following lung transplantation: a retrospective analysis using the universal definition of perioperative bleeding

BACKGROUND

Lung transplantation (LT) represents a high-risk procedure for end-stage lung diseases. This study describes the outcomes of patients undergoing LT that require massive transfusions as defined by the universal definition of perioperative bleeding (UDPB).

METHODS

Adult patients who underwent bilateral LT at a single academic center were surveyed retrospectively. Patients were grouped by insignificant, mild, or moderate perioperative bleeding (insignificant-to-moderate bleeders) and severe or massive perioperative bleeding (severe-to-massive bleeders) based on the UDPB classification. Outcomes included 1-year survival and primary graft dysfunction (PGD) of grade 3 at 72 h postoperatively. Multivariable models were adjusted for recipient age, sex, body mass index (BMI), Lung allocation score (LAS), preoperative hemoglobin (Hb), preoperative extracorporeal membrane oxygenation (ECMO) status, transplant number, and donor status. An additional multivariable model was created to find preoperative and intraoperative predictors of severe-to-massive bleeding. A p-value less than 0.05 was selected for significance.

RESULTS

A total of 528 patients were included, with 357 insignificant-to-moderate bleeders and 171 severe-to-massive bleeders. Postoperatively, severe-to-massive bleeders had higher rates of PGD grade 3 at 72 h, longer hospital stays, higher mortality rates at 30 days and one year, and were less likely to achieve textbook outcomes for LT. They also required postoperative ECMO, reintubation for over 48 h, tracheostomy, reintervention, and dialysis at higher rates. In the multivariate analysis, severe-to-massive bleeding was significantly associated with adverse outcomes after adjusting for recipient and donor factors, with an odds ratio of 7.73 (95% CI: 4.27-14.4, p < 0.001) for PGD3 at 72 h, 4.30 (95% CI: 2.30-8.12, p < 0.001) for 1-year mortality, and 1.75 (95% CI: 1.52-2.01, p < 0.001) for longer hospital stays. Additionally, severe-to-massive bleeders were less likely to achieve textbook outcomes, with an odds ratio of 0.07 (95% CI: 0.02-0.16, p < 0.001). Preoperative and intraoperative predictors of severe/massive bleeding were identified, with White patients having lower odds compared to Black patients (OR: 041, 95% CI: 0.22-0.80, p = 0.008). Each 1-unit increase in BMI decreased the odds of bleeding (OR: 0.89, 95% CI: 0.83-0.95, p < 0.001), while each 1-unit increase in MPAP increased the odds of bleeding (OR: 1.04, 95% CI: 1.02-1.06, p < 0.001). First-time transplant recipients had lower risk (OR: 0.16, 95% CI: 0.06-0.36, p < 0.001), whereas those with DCD donors had a higher risk of severe-to-massive bleeding (OR: 3.09, 95% CI: 1.63-5.87, p = 0.001).

CONCLUSION

These results suggest that patients at high risk of massive bleeding require higher utilization of hospital resources. Understanding their outcomes is important, as it may inform future decisions to transplant comparable patients.

Knockdown of swine leukocyte antigen expression in porcine lung transplants enables graft survival without immunosuppression

Immune rejection remains the major obstacle to long-term survival of allogeneic lung transplants. The expression of major histocompatibility complex molecules and minor histocompatibility antigens triggers allogeneic immune responses that can lead to allograft rejection. Transplant outcomes therefore depend on long-term immunosuppression, which is associated with severe side effects. To address this problem, we investigated the effect of genetically engineered transplants with permanently down-regulated swine leukocyte antigen (SLA) expression to prevent rejection in a porcine allogeneic lung transplantation (LTx) model. Minipig donor lungs with unmodified SLA expression (control group, n = 7) or with modified SLA expression (treatment group, n = 7) were used to evaluate the effects of SLA knockdown on allograft survival and on the nature and strength of immune responses after terminating an initial 4-week period of immunosuppression after LTx. Genetic engineering to down-regulate SLA expression was achieved during ex vivo lung perfusion by lentiviral transduction of short hairpin RNAs targeting mRNAs encoding β2-microglobulin and class II transactivator. Whereas all grafts in the control group were rejected within 3 months, five of seven animals in the treatment group maintained graft survival without immunosuppression during the 2-year monitoring period. Compared with controls, SLA-silenced lung recipients had lower donor-specific antibodies and proinflammatory cytokine concentrations in the serum. Together, these data demonstrate a survival benefit of SLA-down-regulated lung transplants in the absence of immunosuppression.

Is Night Surgery a Nightmare for Lung Transplantation?

Night work is frequently associated with sleep deprivation and is associated with greater surgical and medical complications. Lung transplantation (LT) is carried out both at night and during the day and involves many medical healthcare workers. The goal of the study was to compare morbidity and mortality between LT recipients according to LT operative time. We performed a retrospective, observational, single-center study. When the procedure started between 6 AM and 6 PM, the patient was allocated to the Daytime group. If the procedure started between 6 PM and 6 AM, the patient was allocated to the Nighttime group. Between January 2015 and December 2020, 253 patients were included. A total of 168 (66%) patients were classified into the Day group, and 85 (34%) patients were classified into the Night group. Lung Donors' general characteristics were similar between the groups. The 90-day and one-year mortality rates were similar between the groups (90-days: n = 13 (15%) vs. n = 26 (15%), p = 0.970; 1 year: n = 18 (21%) vs. n = 42 (25%), p = 0.499). Daytime LT was associated with more one-year airway dehiscence (n = 36 (21%) vs. n = 6 (7.1%), p = 0.004). In conclusion, among patients who underwent LT, there was no significant association between operative time and survival.

Health-Related Quality of Life Long-Term Study in Lung Transplant Patients: A Single-Center Experience

INTRODUCTION

Health-related quality of life (HRQL) assessment plays a crucial role in the follow-up care of lung transplanted (LTx) patients. Previous reports have indicated that the HRQL achieved by these patients is often poorer compared to that of healthy individuals. However, the factors contributing to this lower HRQL remain unclear. This prospective study aimed to assess the effectiveness of using both a generic and a disease-specific HRQL instrument in evaluating the outcomes of patients who have undergone LTx.

METHODS

A total of 111 LTx patients were enrolled in the study, with 88 survivors completing the 5-year follow-up and 23 nonsurvivors identified within the first 3 y. Among the participants, 84 underwent double LTx, while 27 received a single LTx. Patients were interviewed before LTx, at 6 mo post-transplantation, and annually thereafter. Two validated instruments were utilized: the Euro quality of life five dimensions, a generic measure, and the St. George's Respiratory Questionnaire (SGRQ), a disease-specific questionnaire.

RESULTS

The study showed significant improvements in Euro Quality of Life five Dimensions scores from 6 mo after LTx. Specifically, the percentage of patients without Mobility problems increased from 23% before LTx to 71% at 5 y (P = <0.001), while the ability to self-care improved from 48% to 100% (P = <0.001). The ability to carry out usual activities improved from 13% to 86% (P = <0.001), and the proportion of patients without anxiety and depression increased from 50% to 86% (P > 0.004). However, there was no significant improvement observed in Pain, with only a slight reduction from 57% to 42.8% (P = 0.22). The SGRQ also showed improvements in all dimensions (symptoms, impact, activities) (P < 0.001). However, by the fifth year, the HRQL scores remained below normal reference values. Chronic graft dysfunction was associated with a decline in SGRQ scores. Bilateral LTx patients exhibited better SGRQ scores compared to unilateral LTx patients from the first year post-transplantation. Notably, there were no differences in scores between nonsurvivors and survivors.

CONCLUSIONS

The study highlights the long-term improvement in HRQL among LTx patients, with greater improvements observed in physical dimensions compared to psychological dimensions. Bilateral LTx was associated with better SGRQ scores than unilateral LTx, and chronic graft dysfunction primarily affected SGRQ scores. These findings underscore the importance of utilizing both generic and specific HRQL instruments in assessing LTx outcomes.

Impact of Difficult Lung Transplantation on Short-Term and Long-Term Survival

BACKGROUND

Lung transplantation (LTx) is a complex operation; however, certain factors can make LTx even more challenging. A difficult LTx could adversely affect immediate and long-term outcomes. We investigate the potential use of Modifier-22 to identify difficult LTx to evaluate postoperative outcomes.

METHODS

A retrospective analysis was performed on patients who had undergone LTx between January 1, 2010, and October 1, 2018, at the University of Washington. Patients undergoing repeat LTx, other solid organ transplantation, and/or with prior major cardiothoracic surgery were excluded. Patients were classified into 2 categories: standard LTx and difficult LTx groups. We examined hospital length of stay (LOS), intensive care unit (ICU) LOS, duration on the ventilator, and 1-, 3-, and 5-year survival.

RESULTS

A total of 370 patients were identified, with 268 patients in the standard LTx group and 102 patients in the difficult LTx group. The median LOS, ICU LOS, and duration on the ventilator in the difficult LTx group was 18.0 ± 1.6 days, 6.0 ± 1.2 days, and 2.0 ± 0.9 days compared with 15.0 ± 0.8 days, 4.0 ± 0.7 days, and 1.0 ± 0.3 days in the standard LTx group, respectively (all P < .01). Kaplan-Meier analysis revealed that both groups had similar survival.

CONCLUSION

Modifier-2 can be used to identify challenging LTx. Difficult LTx negatively impacts early postoperative outcomes with longer LOS, ICU LOS, and duration on the ventilator. However, long-term survival was not affected. Clinicians should not view pleural space and anatomical complexities, which are a consequence of the underlying disease, as a risk factor for impaired survival.

Validation of a novel donor lung scoring system based on the updated lung Composite Allocation Score

Lung transplantation (LTx) continues to have lower rates of long-term graft survival compared with other organs. Additionally, lung utilization rates from brain-dead donors remain substantially lower compared with other solid organs, despite a growing need for LTx and the significant risk of waitlist mortality. This study aims to examine the effects of using a combination of the recently described novel lung donor (LUNDON) acceptability score and the newly adopted recipient lung Composite Allocation Score (CAS) to guide transplantation. We performed a review of nearly 18 000 adult primary lung transplants from 2015-2022 across the US with retroactive calculations of the CAS value. The medium-CAS group (29.6-34.5) had superior 1-year posttransplant survival. Importantly, the combination of high-CAS (> 34.5) recipients with low LUNDON score (≤ 40) donors had the worst survival at 1 year compared with any other combination. Additionally, we constructed a model that predicts 1-year and 3-year survival using the LUNDON acceptability score and CAS values. These results suggest that caution should be exercised when using marginally acceptable donor lungs in high-priority recipients. The use of the LUNDON score with CAS value can potentially guide clinical decision-making for optimal donor-recipient matches for LTx.

Increased Donor Organ Size and Age is Associated with Reduced Survival in Female Lung Transplant Recipients

BACKGROUND

Organ selection in lung transplantation (LTx) is still controversial. We here analyze the impact of mismatches in size, age, and gender on early and long-term outcome after LTx.

METHODS

Retrospective analysis of donor and recipient characteristics of patients who underwent double LTx between March 2003 and December 2021. Statistical analysis was performed using SPSS and GraphPad software.

RESULTS

Two hundred three patients were included (94 women and 109 men). In the whole cohort, oversizing donor organs 10% to 20% compared to the recipients' predicted total lung capacity led to a decreased incidence of severe Primary Graft Dysfunction grades 2 and 3 (2/3; 15% vs 41%, P = .03), and further oversizing > 20% was associated with reduced long-term survival (hazard ratio, 2.33, P = .011). Analyzing donor and recipient age, we found that increased donor age correlated with reduced long-term survival (P = .013). In this cohort, female recipients received older organs (median 57 vs 46 years, P = .0003) and had a higher incidence of > 20% oversizing (13% vs 4%, P = .019) of donor lungs, which resulted in a significantly reduced long-term survival (P = .02) compared with male recipients. Median Lung Allocation Scores were similar in both groups.

CONCLUSION

Mismatch of donor age and size can be important for organ function and survival in LTx recipients. Particularly female recipients seem to have a higher risk for unfavorable long-term outcome when transplanting organs of increased size and age. Multicenter studies are warranted to further address this question.

TRIAL REGISTRATION NUMBER

(DKRS): 00033312.

Impact of Transplant Body Mass Index and Post-Transplant Weight Changes on the Development of Chronic Lung Allograft Dysfunction Phenotypes

INTRODUCTION

Chronic lung allograft dysfunction (CLAD) is a lung transplant complication for which four phenotypes are recognized: Bronchiolitis obliterans syndrome (BOS), Restrictive allograft syndrome (RAS), mixed and undefined phenotypes. Weight gain is common after transplant and may negatively impact lung function. Study objectives were to describe post-transplant weight trajectories of patients who developed (or did not) CLAD phenotypes and examine the associations between BMI at transplant, post-transplant changes in weight and BMI, and the risk of developing these phenotypes.

METHODS

Adults who underwent a bilateral lung transplant between 2000 and 2020 at our institution were categorized as having (or not) one of the four CLAD phenotypes based on the proposed classification system. Demographic, anthropometric, and clinical data were retrospectively collected from medical records and analyzed.

RESULTS

Study population included 579 recipients (412 [71.1%] CLAD-free, 81 [14.0%] BOS, 20 [3.5%] RAS, 59 [10.2%] mixed, and 7 [1.2%] undefined phenotype). Weight gains of greater amplitude were seen in recipients with restrictive phenotypes than CLAD-free and BOS patients within the first five years post-transplant. While the BMI category at transplant was not statistically associated with the risk of developing CLAD phenotypes, an increase in weight (Hazard ratio [HR]: 1.04, 95% CI [1.01-1.08]; P = .008) and BMI (HR: 1.13, 95% CI [1.03-1.23]; P = .008) over the post-transplant period was associated with a greater risk of RAS.

CONCLUSION

Post-LTx gain in weight and BMI modestly increased the risk of RAS, adding to the list of unfavorable outcomes associated with weight gain following transplant.

The gut microbiome in end-stage lung disease and lung transplantation

Gut dysbiosis has been associated with impaired outcomes in liver and kidney transplant recipients, but the gut microbiome of lung transplant recipients has not been extensively explored. We assessed the gut microbiome in 64 fecal samples from end-stage lung disease patients before transplantation and 219 samples from lung transplant recipients after transplantation using metagenomic sequencing. To identify dysbiotic microbial signatures, we analyzed 243 fecal samples from age-, sex-, and BMI-matched healthy controls. By unsupervised clustering, we identified five groups of lung transplant recipients using different combinations of immunosuppressants and antibiotics and analyzed them in relation to the gut microbiome. Finally, we investigated the gut microbiome of lung transplant recipients in different chronic lung allograft dysfunction (CLAD) stages and longitudinal gut microbiome changes after transplantation. We found 108 species (58.1%) in end-stage lung disease patients and 139 species (74.7%) in lung transplant recipients that were differentially abundant compared with healthy controls, with several species exhibiting sharp longitudinal increases from before to after transplantation. Different combinations of immunosuppressants and antibiotics were associated with specific gut microbial signatures. We found that the gut microbiome of lung transplant recipients in CLAD stage 0 was more similar to healthy controls compared to those in CLAD stage 1. Finally, the gut microbial diversity of lung transplant recipients remained lower than the average gut microbial diversity of healthy controls up to more than 20 years post-transplantation. Gut dysbiosis, already present before lung transplantation was exacerbated following lung transplantation.IMPORTANCEThis study provides extensive insights into the gut microbiome of end-stage lung disease patients and lung transplant recipients, which warrants further investigation before the gut microbiome can be used for microbiome-targeted interventions that could improve the outcome of lung transplantation.

Early extracorporeal photopheresis treatment is associated with better survival in patients with chronic or recurrent acute lung allograft dysfunction

BACKGROUND

Due to development of chronic lung allograft dysfunction (CLAD), prognosis for patients undergoing lung transplantation (LTx) is still worse compared to other solid organ transplant recipients. Treatment options for slowing down CLAD progression are scarce with extracorporeal photopheresis (ECP) as an established rescue therapy. The aim of the study was to identify characteristics of responders and non-responders to ECP treatment, assess their survival, lung function development and by that define the subset of patients who should receive early ECP treatment.

METHODS

We performed a retrospective study of all LTx patients receiving ECP treatment at the University Hospital Zurich between January 2010 and March 2020. Patients were followed-up for a maximum period of 5 years. Mortality and lung function development were assessed by CLAD stage and by CLAD subtype before initiation of ECP treatment.

RESULTS

Overall, 105 patients received at least one ECP following LTx. A total of 57 patients (61.3%) died within the study period with a median survival of 15 months. Mortality was 57% for patients who started ECP at CLAD1, 39% for CLAD2, 93% for CLAD3, and 90% for CLAD4 (p < 0.001). Survival and lung function development was best in young patients at early CLAD stages 1 and 2. Response to ECP treatment was worst in patients with CLAD-RAS/mixed subtype (14.3%) and patients with ECP initiation in CLAD stages 3 (7.1%) and 4 (11.1%). Survival was significantly better in a subset of patients with recurrent acute allograft dysfunction and earlier start of ECP treatment (105 vs 15 months).

CONCLUSION

In this retrospective analysis of a large group of CLAD patients treated with ECP after LTx, early initiation of ECP was associated with better long-term survival. Besides a subset of patients suffering of recurrent allograft dysfunction, especially a subset of patients defined as responders showed an improved response rate and survival, suggesting that ECP should be initiated in early CLAD stages and young patients. ECP might therefore prevent long-term disease progression even in patients with CLAD refractory to other treatment options and thus prevent or delay re-transplantation.

HLA-C mismatching improves outcomes following lung transplantation

HLA (HLA) are a major barrier to transplant success, as HLA-A and -B molecules are principal ligands for T-cells, and HLA-C for Killer cell Immunoglobulin-like Receptors (KIR), directing Natural Killer (NK) cell function. HLA-C molecules are designated "C1" or "C2" ligands based on residues 77 and 80, which determine the NK cell responses. Here, we investigated donor/recipient HLA-C mismatch associations with the development of chronic lung allograft dysfunction (CLAD) following lung transplantation (LTx). 310 LTx donor/recipient pairs were Next Generation Sequenced and assessed for C1 and C2 allotypes. PIRCHE scores were used to quantify HLA mismatching between donor/recipients at amino acid level and stratify recipients into low, moderate or highly mismatched groups (n = 103-104). Associations between C ligands and freedom from CLAD was assessed with Cox regression models and survival curves. C2/C2 recipients (n = 42) had less CLAD than those with C1/C1 (n = 138) or C1/C2 genotypes (n = 130) (p < 0.05). Incidence of CLAD was lower in C2/C2 recipients receiving a mismatched C1/C1 allograft (n = 14), compared to matched (n = 8) or heterozygous (n = 20) allografts. Furthermore, ~80% of these recipients (C2/C2 recipients receiving C1/C1 transplants) remained CLAD-free for 10 years post-LTx. Recipients with higher HLA-C mismatching had less CLAD (p < 0.05) an observation not explained by linkage disequilibrium with other HLA loci. Our data implicates a role for HLA-C in CLAD development. HLA-C mismatching was not detrimental to LTx outcome, but potentially beneficial, representing a paradigm shift in assessing donor/recipient matching. This may inform better selection of donor/recipient pairs and potentially more targeted approaches to treating CLAD.

Bibliometric Analysis of Scientific Output Growth in the Field of Lung Transplantation

BACKGROUND

 Lung transplantation (LT) has recently emerged as a scientifically validated curative therapeutic modality for patients afflicted with end-stage lung disease. This study aimed to conduct a global bibliometric analysis of research articles on LT between 1983 and 2021.

METHODS

 Employing the Web of Science database, a bibliometric analysis was conducted to assess the expansion of scientific output within the field of LT. We searched specific bibliometric characteristics such as language, and year of publication, first author, institutional affiliation, main publishing journals, and highly cited articles. Additionally, we made comparisons of the most productive countries. The VOSviewer program and the open-source visualization software Biblioshiny (version 2.0) were used to perform the bibliometric analysis.

RESULTS

 We identified 10,467 articles on LT published between 1983 and 2021, of which 94.898% were published in the Science Citation Index Expanded. The articles were from 101 different research areas. The publications were from 81 different countries globally, and mostly from the United States (41.196%), Germany (7.118%), and Canada (6.372%). The Journal of Heart and Lung Transplantation was the most published journal. Four thousand seven hundred and ninety three of the publications were published in the last 10 years with a 78,781 citation number in total. The highest number of publications and citations was in 2021.

CONCLUSION

 The majority of cutting-edge research findings are focused on only a few developed nations, and exchanges with emerging nations are still in their infancy. The United States has a strong, commanding position among the active countries in LT.

Interstitial Lung Disease: A Review

Importance

Interstitial lung disease (ILD) consists of a group of pulmonary disorders characterized by inflammation and/or fibrosis of the lung parenchyma associated with progressive dyspnea that frequently results in end-stage respiratory failure. In the US, ILD affects approximately 650 000 people and causes approximately 25 000 to 30 000 deaths per year.

Observations

The most common forms of ILD are idiopathic pulmonary fibrosis (IPF), which accounts for approximately one-third of all cases of ILD, hypersensitivity pneumonitis, accounting for 15% of ILD cases, and connective tissue disease (CTD), accounting for 25% of ILD cases. ILD typically presents with dyspnea on exertion. Approximately 30% of patients with ILD report cough. Thoracic computed tomography is approximately 91% sensitive and 71% specific for diagnosing subtypes of ILDs such as IPF. Physiologic assessment provides important prognostic information. A 5% decline in forced vital capacity (FVC) over 12 months is associated with an approximately 2-fold increase in mortality compared with no change in FVC. Antifibrotic therapy with nintedanib or pirfenidone slows annual FVC decline by approximately 44% to 57% in individuals with IPF, scleroderma associated ILD, and in those with progressive pulmonary fibrosis of any cause. For connective tissue disease-associated ILD, immunomodulatory therapy, such as tocilizumab, rituximab, and mycophenolate mofetil, may slow decline or even improve FVC at 12-month follow-up. Structured exercise therapy reduces symptoms and improves 6-minute walk test distance in individuals with dyspnea. Oxygen reduces symptoms and improves quality of life in individuals with ILD who desaturate below 88% on a 6-minute walk test. Lung transplant may improve symptoms and resolve respiratory failure in patients with end-stage ILD. After lung transplant, patients with ILD have a median survival of 5.2 to 6.7 years compared with a median survival of less than 2 years in patients with advanced ILD who do not undergo lung transplant. Up to 85% of individuals with end-stage fibrotic ILD develop pulmonary hypertension. In these patients, treatment with inhaled treprostinil improves walking distance and respiratory symptoms.

Conclusions and Relevance

Interstitial lung disease typically presents with dyspnea on exertion and can progress to respiratory failure. First-line therapy includes nintedanib or pirfenidone for IPF and mycophenolate mofetil for ILD due to connective tissue disease. Lung transplant should be considered for patients with advanced ILD. In patients with ILD, exercise training improves 6-minute walk test distance and quality of life.

Pulmonary transplant complications: a radiologic review

Lung transplantation has become the definitive treatment for end stage respiratory disease. Numbers and survival rates have increased over the past decade, with transplant recipients living longer and with greater comorbidities, resulting in greater complexity of care. Common and uncommon complications that occur in the immediate, early, intermediate, and late periods can have significant impact on the course of the transplant. Fortunately, advancements in surgery, medical care, and imaging as well as other diagnostics work to prevent, identify, and manage complications that would otherwise have a negative impact on survivability. This review will focus on contextualizing complications both categorically and chronologically, with highlights of specific imaging and clinical features in order to inform both radiologists and clinicians involved in post-transplant care.