Survival impact of lung transplantation for COPD

Identification of Neutrophil Extracellular Trap-Related Gene Expression Signatures in Ischemia Reperfusion Injury During Lung Transplantation: A Transcriptome Analysis and Clinical Validation

Purpose

Ischemia reperfusion injury (IRI) unavoidably occurs during lung transplantation, further contributing to primary graft dysfunction (PGD). Neutrophils are the end effectors of IRI and activated neutrophils release neutrophil extracellular traps (NETs) to further amplify damage. Nevertheless, potential contributions of NETs in IRI remain incompletely understood. This study aimed to explore NET-related gene biomarkers in IRI during lung transplantation.

Methods

Differential expression analysis was applied to identify differentially expressed genes (DEGs) for IRI during lung transplantation based on matrix data (GSE145989, 127003) downloaded from GEO database. The CIBERSORT and weighted gene co-expression network analysis (WGCNA) algorithms were utilized to identify key modules associated with neutrophil infiltration. Moreover, the least absolute shrinkage and selection operator regression and random forest were applied to identify potential NET-associated hub genes. Subsequently, the screened hub genes underwent further validation of an external dataset (GSE18995) and nomogram model. Based on clinical peripheral blood samples, immunofluorescence staining and dsDNA quantification were used to assess NET formation, and ELISA was applied to validate the expression of hub genes.

Results

Thirty-eight genes resulted from the intersection between 586 DEGs and 75 brown module genes, primarily enriched in leukocyte migration and NETs formation. Subsequently, four candidate hub genes (FCAR, MMP9, PADI4, and S100A12) were screened out via machine learning algorithms. Validation using an external dataset and nomogram model achieved better predictive value. Substantial NETs formation was demonstrated in IRI, with more pronounced NETs observed in patients with PGD ≥ 2. PADI4, S100A12, and MMP9 were all confirmed to be up-regulated after reperfusion through ELISA, with higher levels of S100A12 in PGD ≥ 2 patients compared with non-PGD patients.

Conclusion

We identified three potential NET-related biomarkers for IRI that provide new insights into early detection and potential therapeutic targets of IRI and PGD after lung transplantation.

Impact of pharmacological and non-pharmacological interventions on mortality in chronic obstructive pulmonary disease (COPD) patients

PURPOSE

This review aimed to summarise evidence about the impact of pharmacological and non-pharmacological interventions on survival in COPD patients.

METHODS

We performed a narrative literature review on the effect of pharmacological and non-pharmacological interventions on survival in COPD patients.

RESULTS

Inhaled therapies are central to reduce symptoms in COPD. In particular, inhaled steroids seem to have the greatest effect on mortality. Despite the anti-inflammatory effects attributed to statins, their benefit in COPD has been shown only in cases of combined cardiovascular diseases. The use of beta-blockers in COPD has not been associated with increased COPD-related mortality and a beneficial effect on all-cause mortality has even been shown in COPD patients with cardiovascular diseases. Influenza and pneumococcal vaccination reduced the occurrence of exacerbations and mortality due to COPD. In addition, long-term oxygen therapy (LTOT) (≥15h/day) in COPD patients with severe hypoxemia had a positive effect on survival. Regarding non-pharmacological interventions, it has been demonstrated that smoking cessation, treatment compliance and nutritional supplementation for underweight patients also have a positive effect on survival. Non-invasive ventilation results were dependent on patient PaCO2 levels. In patients with advanced COPD, further prospective studies are needed to know the effect of bronchoscopic lung volume reduction and lung transplant on COPD survival. Regarding lung transplant, a survival benefit in patients with a pre-transplant BODE score of ≥7 has been shown in retrospective studies.

CONCLUSION

Most of the studies did not evaluate survival as the main criteria and further long-term studies on the global management of COPD are required.

2022 Update of indications and contraindications for lung transplantation in France

Lung transplantation (LTx) is a steadily expanding field. The considerable developments have been driven over the years by indefatigable work conducted at LTx centers to improve donor and recipient selection, combined with multifaceted efforts to overcome challenges raised by the surgical procedure, perioperative care, and long-term medical complications. One consequence has been a pruning away of contraindications over time, which has, in some ways, complicated the patient selection process. The Francophone Pulmonology Society (Société de Pneumology de Langue Française, SPLF) set up a task force to produce up-to-date working guidelines designed to assist pulmonologists in managing end-stage respiratory insufficiency, determining which patients may be eligible for LTx, and appropriately timing LTx-center referral. The task force examined the most recent literature and evaluated the risk factors that limit patient survival after LTx. Ideally, the objectives of LTx are to prolong life while also improving quality of life. The guidelines developed by the task force apply to a limited resource and are consistent with the ethical principles described below.

Lung transplantation for chronic obstructive pulmonary disease: A call to modify the lung allocation score to decrease waitlist mortality

OBJECTIVE

Approximately 40% of lung transplants for chronic obstructive pulmonary disease (COPD) in the lung allocation score era are single lung transplantations (SLTs). We hypothesized that double lung transplantation (DLT) results in superior survival, but that mortality on the waitlist may compel clinicians to perform SLT. We investigated both waitlist mortality in COPD patients with restricted versus unrestricted listing preferences and posttransplant survival in SLT versus DLT to identify key predictors of mortality.

METHODS

A retrospective analysis of waitlist mortality and posttransplant survival in patients with COPD was conducted using post-lung allocation score data from the United Network for Organ Sharing database between 2005 and 2018.

RESULTS

Of 6740 patients with COPD on the waitlist, 328 (4.87%) died and 320 (4.75%) were removed due to clinical deterioration. Median survival on the waitlist was significantly worse in patients listed as restricted for DLT (4.39 vs 6.09 years; P = .002) compared with patients listed as unrestricted (hazard ratio, 1.34; 95% CI, 1.13-1.57). Factors that increase waitlist mortality include female sex, increased pulmonary artery pressure, and increased wait time. Median posttransplant survival was 5.3 years in SLT versus 6.5 years in DLT (P < .001). DLT recipients are younger, male patients with a higher lung allocation score. The survival advantage of DLT persisted in adjusted analysis (hazard ratio, 0.819; 95% CI, 0.741-0.905).

CONCLUSIONS

Restricted listing preference is associated with increased waitlist mortality, but DLT recipients have superior posttransplant survival. Because the lung allocation score does not prioritize COPD, concern for increased waitlist mortality with restricted listing preference may drive continued use of SLT despite better posttransplant survival in DLT.

Screening gene signatures for clinical response subtypes of lung transplantation

Lung is the most important organ in the human respiratory system, whose normal functions are quite essential for human beings. Under certain pathological conditions, the normal lung functions could no longer be maintained in patients, and lung transplantation is generally applied to ease patients' breathing and prolong their lives. However, several risk factors exist during and after lung transplantation, including bleeding, infection, and transplant rejections. In particular, transplant rejections are difficult to predict or prevent, leading to the most dangerous complications and severe status in patients undergoing lung transplantation. Given that most common monitoring and validation methods for lung transplantation rejections may take quite a long time and have low reproducibility, new technologies and methods are required to improve the efficacy and accuracy of rejection monitoring after lung transplantation. Recently, one previous study set up the gene expression profiles of patients who underwent lung transplantation. However, it did not provide a tool to predict lung transplantation responses. Here, a further deep investigation was conducted on such profiling data. A computational framework, incorporating several machine learning algorithms, such as feature selection methods and classification algorithms, was built to establish an effective prediction model distinguishing patient into different clinical subgroups, corresponding to different rejection responses after lung transplantation. Furthermore, the framework also screened essential genes with functional enrichments and create quantitative rules for the distinction of patients with different rejection responses to lung transplantation. The outcome of this contribution could provide guidelines for clinical treatment of each rejection subtype and contribute to the revealing of complicated rejection mechanisms of lung transplantation.

Current trends in candidate selection, contraindications, and indications for lung transplantation

Lung transplantation is an established treatment option that can improve quality of life and prolong survival for select patients diagnosed with end-stage lung disease. Given the gaps in organ donation and failures to make effective use of available organs, careful selection of candidates for lung transplant remains one of the most important considerations of the transplant community. Toward this end, we briefly reviewed recent trends in pretransplant evaluation, candidate selection, organ allocation, and organ preservation techniques. Since the latest consensus statement regarding appropriate selection of lung transplant candidates, many advances in the science and practice of lung transplantation have emerged and influenced our perspective of ‘contraindications’ to transplant. These advances have made it increasingly possible to pursue lung transplant in patients with risk factors for decreased survival—namely, older recipient age, increased body mass index, previous chest surgery, poorer nutritional status, and presence of chronic infection, cardiovascular disease, or extrapulmonary comorbid conditions. Therefore, we reviewed the updated evidence demonstrating the prognostic impact of these risk factors in lung transplant recipients. Lastly, we reviewed the salient evidence for current trends in disease-specific indications for lung transplantation, such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, emphysema due to alpha-1 antitrypsin deficiency, and pulmonary arterial hypertension, among other less common end-stage diseases. Overall, lung transplant remains an exciting field with considerable hope for patients as they experience remarkable improvements in quality of life and survival in the modern era.

Pro-inflammatory IgG1 N-glycan signature correlates with primary graft dysfunction onset in COPD patients

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. The pathogenesis of COPD is complex; however, recent studies suggest autoimmune changes, characterized by the presence of autoantibodies to elastin and collagen, may contribute to disease status. COPD patients make up approximately 30% of all lung transplants (LTx) annually, however, little is known regarding the relationship between COPD-related autoantibodies and LTx outcomes. We hypothesized that COPD patients that undergo LTx and develop primary graft dysfunction (PGD) have altered circulating autoantibody levels and phenotypic changes as compared those COPD-LTx recipients that do not develop PGD. We measured total immunoglobulin and circulating elastin and collagen autoantibody levels in a cohort of COPD lung transplant recipients pre- and post-LTx. No significant differences were seen in total, elastin, or collagen IgM, IgG, IgG1, IgG2, IgG3, and IgG4 antibodies between PGD+ and PGD- recipients. Antibody function can be greatly altered by glycosylation changes to the antibody Fc region and recent studies have reported altered IgG glycosylation profiles in COPD patients. We therefore utilized a novel mass spectrometry-based multiplexed N-glycoprotein imaging approach and measured changes in IgG-specific antibody N-glycan structures. COPD-LTx recipients who developed PGD had significantly increased IgG1 N-glycan signatures as compared PGD- recipients. In conclusion, we show that immunoglobulin and autoreactive antibody levels are not significantly different in COPD LTx recipients that develop PGD. However, using a novel IgG glycomic analysis we were able to demonstrate multiple significant increases in IgG1 specific N-glycan signatures that were predictive of PGD development. Taken together, these data represent a potential novel method for identifying COPD patients at risk for PGD development and may provide clues to mechanisms by which antibody N-glycan signatures could contribute to antibody-mediated PGD pathogenesis.

Lung Transplantation in COPD

Chronic obstructive pulmonary disease (COPD) remains one of the leading causes of morbidity and mortality both in the United States and worldwide. Despite advances in medical treatment including smoking cessation, bronchodilator therapy, oxygen administration, and pulmonary rehabilitation, patients with advanced COPD still suffer significant debility. For select patients with severe COPD, there are additional surgical options including lung volume reduction surgery and ultimately lung transplantation.This article discusses the history, clinical indications, selection of candidates, choice of procedure, and outcomes of lung transplantation in patients with advanced COPD. In addition, certain aspects of potential short- and long-term complications of transplantation will also be discussed.

Chronic Obstructive Pulmonary Disease and Lung Transplantation

Lung transplantation (LTx) has been a viable option for patients with end-stage chronic obstructive pulmonary disease (COPD), with more than 20,000 procedures performed worldwide. Survival after LTx lags behind most other forms of solid-organ transplantation, with median survival for COPD recipients being a sobering 6.0 years. Given the limited supply of suitable donor organs, not all patients with end-stage COPD are candidates for LTx. We discuss appropriate criteria for accepting patients for LTx, as well as contraindications and exclusionary criteria. In the first year post-LTx, infection and graft failure are the leading causes of death. Beyond this chronic graft rejection-currently referred to as chronic lung allograft dysfunction-represents the leading cause of death at all time points, with infection and over time malignancy also limiting survival. Referral of COPD patients to a lung transplant center should be considered in the presence of progressing disease despite maximal medical therapy. As a rule of thumb, a forced expiratory volume in 1 second < 25% predicted in the absence of exacerbation, hypoxia (PaO₂ < 60 mm Hg/8 kPa), and/or hypercapnia (PaCO₂ > 50 mm Hg/6.6 kPa) and satisfactory general clinical condition should be considered the basic prerequisites for timely referral. We also discuss salient issues post-LTx and factors that impact posttransplant survival and morbidity such as infections, malignancy, renal insufficiency, and complications associated with long-term immunosuppression.

Outcome of Lung Transplantation as a Treatment of Patients With Chronic Obstructive Pulmonary Disease: A Single-Center Study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide. Lung transplantation (LTx) is often the only therapeutic option for patients with end-stage COPD. The aim of the study was to establish whether patients with end-stage COPD benefited from lung transplantation and assess the pulmonary function by the 6-Minute Walk Test (6MWT) and forced expiratory volume in 1 second (FEV1).

METHODS

A retrospective study was carried out in the group of 69 patients (40 recipients, 18 patients currently waiting, and 11 patients who died while waiting for a lung graft) diagnosed with end-stage COPD, referred to the Silesian Center for Heart Diseases' Lung Transplant Ward, and qualified to be treated by means of lung transplantation between 2006 and 2018. The beginning of the observation for all 69 patients was a qualification date.

RESULTS

Kaplan-Meier estimation determined that graft recipients noted 50% probability of survival at approximately 5.5 years, whereas patients from the other group had such parameters at about 1.4 years. The average results FEV1 obtained at qualification were 23.69% for single lung transplantation (SLT); and 22.06% for double lung transplantation (DLT). Average patient acquired 158.07m in the 6MWT. One year after procedure the average values of FEV1 were SLT, 55.83%; DLT, 79.54%; and 430.7 m in the 6MWT overall.

CONCLUSIONS

Qualified patients who underwent lung transplantation lived longer than those who did not undergo such a procedure. We observed a difference in SLT and DLT recipients.

Chronic Obstructive Pulmonary Disease and the Optimal Timing of Lung Transplantation

Chronic obstructive pulmonary disease (COPD) accounts for the largest proportion of respiratory deaths worldwide and was historically the leading indication for lung transplantation. The success of lung transplantation procedures is measured as survival benefit, calculated as survival with transplantation minus predicted survival without transplantation. In chronic obstructive pulmonary disease, it is difficult to show a clear and consistent survival benefit. Increasing knowledge of the risk factors, phenotypical heterogeneity, systemic manifestations, and their management helps improve our ability to select candidates and list those that will benefit the most from the procedure.

Lung tissue bioengineering for chronic obstructive pulmonary disease: overcoming the need for lung transplantation from human donors

Introduction: Chronic obstructive pulmonary disease (COPD) affects more than 380 million people, causing more than 3 million deaths annually worldwide. Despite this enormous burden, currently available therapies are largely limited to symptom control. Lung transplant is considered for end-stage disease but is severely limited by the availability of human organs. Furthermore, the pre-transplant course is a complex orchestration of locating and harvesting suitable lungs, and the post-transplant course is complicated by rejection and infection. Lung tissue bioengineering has the potential to relieve the organ shortage and improve the post-transplant course by generating patient-specific lungs for transplant. Additionally, emerging progenitor cell therapies may facilitate in vivo regeneration of pulmonary tissue, obviating the need for transplant. Areas Covered: We review several lung tissue bioengineering approaches including the recellularization of decellularized scaffolds, 3D bioprinting, genetically-engineered xenotransplantation, blastocyst complementation, and direct therapy with progenitor cells. Articles were identified by searching relevant terms (see Key Words) in the PubMed database and selected for inclusion based on novelty and uniqueness of their approach. Expert Opinion: Lung tissue bioengineering research is in the early stages. Of the methods reviewed, only direct cell therapy has been investigated in humans. We anticipate a minimum of 5-10 years before human therapy will be feasible.

External Validation and Recalculation of the CODEX Index in COPD Patients. A 3CIAplus Cohort Study

The CODEX index was developed and validated in patients hospitalized for COPD exacerbation to predict the risk of death and readmission within one year after discharge. Our study aimed to validate the CODEX index in a large external population of COPD patients with variable durations of follow-up. Additionally, we aimed to recalculate the thresholds of the CODEX index using the cutoffs of variables previously suggested in the 3CIA study (mCODEX). Individual data on 2,755 patients included in the COPD Cohorts Collaborative International Assessment Plus (3CIA+) were explored. A further two cohorts (ESMI AND EGARPOC-2) were added. To validate the CODEX index, the relationship between mortality and the CODEX index was assessed using cumulative/dynamic ROC curves at different follow-up periods, ranging from 3 months up to 10 years. Calibration was performed using univariate and multivariate Cox proportional hazard models and Hosmer-Lemeshow test. A total of 3,321 (87.8% males) patients were included with a mean ± SD age of 66.9 ± 10.5 years, and a median follow-up of 1,064 days (IQR 25-75% 426-1643), totaling 11,190 person-years. The CODEX index was statistically associated with mortality in the short- (≤3 months), medium- (≤1 year) and long-term (10 years), with an area under the curve of 0.72, 0.70 and 0.76, respectively. The mCODEX index performed better in the medium-term (<1 year) than the original CODEX, and similarly in the long-term. In conclusion, CODEX and mCODEX index are good predictors of mortality in patients with COPD, regardless of disease severity or duration of follow-up.

Lung transplantation for chronic obstructive pulmonary disease: past, present, and future directions

PURPOSE OF REVIEW

Lung transplantation offers an effective treatment modality for patients with end-stage chronic obstructive pulmonary disease (COPD). The exact determination of when to refer, list, and offer transplant as well as the preferred transplant procedure type remains unclear. Additionally, there are special considerations specific to patients with COPD being considered for lung transplantation, including the implications of single lung transplantation on lung cancer risk, native lung hyperinflation, and overall survival.

RECENT FINDINGS

The International Society for Heart and Lung Transplantation's most recent recommendations rely on an assessment of COPD severity based on BODE index. Despite the lack of evidence supporting a mortality benefit of bilateral over single lung transplantation for COPD patients, the majority of transplants performed in this population remain bilateral. Some of the concerns specific to single lung transplantation remain the possibility of de novo native lung cancer and the hemodynamic and physiologic implications of acute native lung hyperinflation.

SUMMARY

COPD remains the most common worldwide indication for lung transplantation. Ongoing study is still required to assess the overall survival benefit of lung transplantation and assess the overall quality of life impact on the COPD patient population.

Lung Allocation Score Thresholds Prioritize Survival After Lung Transplantation

BACKGROUND

The lung allocation score (LAS) prioritizes lung transplant (LTx) candidates with poor transplant-free survival and expected survival benefit from LTx. Although patients with the highest LAS have the shortest waiting time, mortality benefit is unclear in this group, raising criticism that the LAS inappropriately prioritizes critically ill candidates. We aim to identify a threshold above which increasing LAS values do not predict increasing survival benefit.

METHODS

The United Network for Organ Sharing Registry was queried for first-time adult LTx candidates with LAS ≥ 30 between May 2005 and December 2016. Survival was tracked from the time of listing through the posttransplant period and compared with survival while remaining on the waitlist, using proportional hazards regression. The survival benefit of LTx was modeled as a piecewise-constant time-dependent covariate, moderated by candidate LAS.

RESULTS

Of the overall cohort (N = 21,157), LTx was particularly protective for 365 patients with an initial LAS of 70 to 79 (hazard ratio of death after undergoing LTx relative to remaining on the waitlist, 0.2; 95% CI, 0.1-0.3). However, the survival benefit of LTx did not meaningfully increase for 1,042 patients listed with even higher LAS. Among patients with cystic fibrosis, the survival benefit of LTx was constant above an LAS of approximately 50.

CONCLUSIONS

Consistent survival benefit of LTx was observed among patients with an initial LAS of 70 and greater. This result supports equalizing priority for donor lung allocation for patients with LAS ≥ 70. A lower LAS threshold for maximum priority is indicated in patients with cystic fibrosis.

Reassessing the BODE score as a criterion for listing COPD patients for lung transplantation

BACKGROUND

The BODE score (incorporating body mass index, airflow obstruction, dyspnea and exercise capacity) is used for the timing of listing for lung transplantation (LTx) in COPD, based on survival data from the original BODE cohort. This has limitations, because the original BODE cohort differs from COPD patients who are candidates for LTx and the BODE does not include parameters that may influence survival. Our goal was to assess whether parameters such as age, smoking status and diffusion indices significantly influence survival in the absence of LTx, independently of the BODE.

METHODS

In the present cohort study, the BODE was prospectively assessed in COPD patients followed in a tertiary care hospital with an LTx program. The files of 469 consecutive patients were reviewed for parameters of interest (age, gender, smoking status and diffusing capacity of the lungs for carbon monoxide [DL,CO]) at the time of BODE assessment, as well as for survival status. Their influence on survival independent of the BODE score was assessed, as well as their ability to predict survival in patients aged less than 65 years.

RESULTS

A Cox regression model showed that the BODE score, age and DL,CO were independently related to survival (P-values <0.001), as opposed to smoking status. Survival was better in patients aged less than 65 in the first (P=0.004), third (P=0.002) and fourth BODE quartiles (P=0.008). The difference did not reach significance in the second quartile (P=0.13). Median survival for patients aged less than 65 in the fourth BODE quartile was 55 months. According to a receiver operating characteristic curve analysis, the BODE score as well as FEV1 and DL,CO fared similarly in predicting survival status at 5 years in patients aged less than 65 years.

CONCLUSION

Age and DL,CO add to the BODE score to predict survival in COPD. Assessing survival using tools tested in cohorts of patients younger than 65 years is warranted for improving the listing of patients for LTx.

Transplant options for end stage chronic obstructive pulmonary disease in the context of multidisciplinary treatments

Lung transplantation (LTx) in advanced stage chronic obstructive pulmonary disease (COPD) patients is associated with significant improvement in lung function and exercise capacity. However, demonstration that the procedure also provides a survival benefit has been more elusive compared to other respiratory conditions. Identification of patients with increased risk of mortality is crucial: a low forced expiratory volume in 1 second (FEV₁) is perhaps the most common reason for referral to a lung transplant center, but in itself is insufficient to identify which COPD patients will benefit from LTx. Many variables have to be considered in the selection of candidates, time for listing, and choice of procedure: age, patient comorbidities, secondary pulmonary hypertension, the balance between individual and community benefit. This review will discuss patient selection, transplant listing, potential benefits and critical issues of bilateral (BLTx) and single lung (SLTx) procedure, donor-to-recipient organ size-matching; furthermore, it will describe LTx outcomes and its effects on recipient survival and quality of life.

Endobronchial coil therapy in severe emphysema: 6-month outcomes from a Swiss National Registry

BACKGROUND

Endobronchial coils have been demonstrated in three randomized, controlled trials to improve quality of life, exercise tolerance, and lung function in patients with severe emphysema. This therapy is CE-marked and commercially available in Switzerland. Coil treated patients are followed in a post-market Swiss registry to collect safety and effectiveness data in routine clinical practice.

METHODS

The Swiss coil registry was initiated in October 2013. At the end of November 2016, an interim analysis of all 64 patients treated in five centers was performed to evaluate safety and effectiveness at six months post treatment.

RESULTS

patients had completed bilateral treatment with 6-month follow up at the time of data analysis. Patients had very severe, symptomatic emphysema and hyperinflation [38% male, mean age 66 years, BMI 24, FEV1 30% pred., residual volume (RV) 247% pred., 6-minute walking distance (6-MWD) 272 m, St. George Respiratory Questionnaire (SGRQ) 57 points]. Up to 6 months following treatment, seven serious adverse events (SAE) were reported in 6/29 patients. No device removals were necessary. At 6 months, responder rates [% achieving the minimal clinically important difference (MCID)] were as follows: RV (-0.35 L) 76%; FEV1 (+10%) 57%; SGRQ (-4 points) 87%; 6MWD (+26 m) 60%.

CONCLUSIONS

Endobronchial coil therapy performed in expert centers in Switzerland yields high 6-month responder rates across all relevant outcome.

Lung transplantation: indications and contraindications

The selection of appropriate recipients for lung transplantation is an evolving discipline. As experience with the procedure has developed over the last decades, the identification of transplant candidates has also changed as transplant centers strive to safely provide the therapy to as many patients possible. The International Society for Heart and Lung Transplantation (ISHLT) has developed three editions of recipient selection guidelines. Published in 1998, 2006, and 2015, these guidelines represented the best information relevant to the appropriate selection of lung transplant candidates. A discussion of areas supported by the most robust scientific data will be undertaken, but in many aspects of recipient selection, there is a paucity of data upon which to rely. Therefore, it is ultimately the prerogative and responsibility of individual centers to determine, after carefully weighing the best evidence available, whether a patient is deemed a suitable candidate at a specific program. All possible indications and contraindications for transplantation will be reviewed with attention also given to the appropriate timing of referral and listing of patients with advanced lung disease to a transplant center.

Survival Benefit of Lung Transplantation in the Modern Era of Lung Allocation

RATIONALE

Lung transplantation is an accepted and increasingly employed treatment for advanced lung diseases, but the anticipated survival benefit of lung transplantation is poorly understood.

OBJECTIVES

To determine whether and for which patients lung transplantation confers a survival benefit in the modern era of U.S. lung allocation.

METHODS

Data on 13,040 adults listed for lung transplantation between May 2005 and September 2011 were obtained from the United Network for Organ Sharing. A structural nested accelerated failure time model was used to model the survival benefit of lung transplantation over time. The effects of patient, donor, and transplant center characteristics on the relative survival benefit of transplantation were examined.

MEASUREMENTS AND MAIN RESULTS

Overall, 73.8% of transplant recipients were predicted to achieve a 2-year survival benefit with lung transplantation. The survival benefit of transplantation varied by native disease group (P = 0.062), with 2-year expected benefit in 39.2 and 98.9% of transplants occurring in those with obstructive lung disease and cystic fibrosis, respectively, and by lung allocation score at the time of transplantation (P < 0.001), with net 2-year benefit in only 6.8% of transplants occurring for lung allocation score less than 32.5 and in 99.9% of transplants for lung allocation score exceeding 40.

CONCLUSIONS

A majority of adults undergoing transplantation experience a survival benefit, with the greatest potential benefit in those with higher lung allocation scores or restrictive native lung disease or cystic fibrosis. These results provide novel information to assess the expected benefit of lung transplantation at an individual level and to enhance lung allocation policy.

Survival of Lung Transplant Candidates With COPD: BODE Score Reconsidered

BACKGROUND

The BMI, obstruction, dyspnea, and exercise capacity (BODE) score is used to inform prognostic considerations for lung transplantation for COPD, but it has not been validated in this context. A large proportion of mortality in COPD is attributable to comorbidities that could preclude transplant candidacy. We hypothesized that patients with COPD who are selected as transplant candidates experience better survival than traditional interpretation of BODE scores might indicate.

METHODS

We performed a retrospective analysis of survival according to the BODE score for patients with COPD in the United Network of Organ Sharing (UNOS) database of lung transplantation candidates (n = 4,377) compared with the cohort of patients with COPD in which the BODE score was validated (n = 625).

RESULTS

Median survival in the fourth quartile of BODE score was 59 months (95% CI, 51-77 months) in the UNOS cohort and 37 months (95% CI, 29-42 months) in the BODE validation cohort. In models controlling for BODE score and incorporating lung transplantation as a competing end point, the risk of death was higher in the BODE validation cohort (subhazard ratio, 4.8; 95% CI, 4.0-5.7; P < .001). The risk difference was greatest in the fourth quartile of BODE scores (SHR, 6.1; 95% CI, 4.9-7.6; P < .001).

CONCLUSIONS

Extrapolation of prognosis based on the BODE score overestimates mortality risk in lung transplantation candidates with COPD. This is likely due to a lower prevalence of comorbid conditions attributable to the lung transplantation evaluation screening process.

Recipient selection process and listing for lung transplantation

Lung transplantation remains the ultimate treatment option for selected patients with end-stage (cardio) pulmonary disease. Given the current organ shortage, it is without any doubt that careful selection of potential transplant candidates is essential as this may greatly influence survival after the procedure. In this paper, we will review the current guidelines for referral and listing of lung transplant candidates in general, and in more depth for the specific underlying diseases. Needless to state that these are not absolute guidelines, and that decisions depend upon center's activity, waiting list, etc. Therefore, every patient should be discussed with the transplant center before any definite decision is made to accept or decline a patient for lung transplantation.

Outcomes after lung transplantation

With more than 50,000 procedures having been performed worldwide, lung transplantation (LT) has become the standard of care for patients with end-stage chronic respiratory failure. LT leads to dramatic improvements in both pulmonary function and health related quality of life. Survival after LTs has steadily improved, but still lags far behind that observed after other solid organ transplantations, as evidenced by a median survival rate that currently stands at 5.8 years. Because of these disappointing results, the ability of LT to expand survival has been questioned. However, the most recent studies, based on sophisticated statistical modeling suggest that LT confers a survival benefit to the vast majority of lung transplant recipients. Chronic lung allograft dysfunction (CLAD) that develops in about 50% of recipients 5 years after LT is a major impediment to lung transplant survival. A better understanding of the mechanisms underlying CLAD could allow for better post-transplant survival.

Comprehensive Care of the Lung Transplant Patient

Lung transplantation has evolved into a life-saving treatment with improved quality of life for patients with end-stage respiratory failure unresponsive to other medical or surgical interventions. With improving survival rates, the number of lung transplant recipients with preexisting and posttransplant comorbidities that require attention continues to increase. A partnership between transplant and nontransplant care providers is necessary to deliver comprehensive and optimal care for transplant candidates and recipients. The goals of this partnership include timely referral and assistance with transplant evaluation, optimization of comorbidities and preparation for transplantation, management of common posttransplant medical comorbidities, immunization, screening for malignancy, and counseling for a healthy lifestyle to maximize the likelihood of a good outcome. We aim to provide an outline of the main aspects of the care of candidates for and recipients of lung transplants for nontransplant physicians and other care providers.

[Indications of lung transplantation: Patients selection, timing of listing, and choice of procedure]

Lung transplantation (LT) is now considered as an excellent treatment option for selected patients with end-stage pulmonary diseases, such as COPD, cystic fibrosis, idiopathic pulmonary fibrosis, and pulmonary arterial hypertension. The 2 goals of LT are to provide a survival benefit and to improve quality of life. The 3-step decision process leading to LT is discussed in this review. The first step is the selection of candidates, which requires a careful examination in order to check absolute and relative contraindications. The second step is the timing of listing for LT; it requires the knowledge of disease-specific prognostic factors available in international guidelines, and discussed in this paper. The third step is the choice of procedure: indications of heart-lung, single-lung, and bilateral-lung transplantation are described. In conclusion, this document provides guidelines to help pulmonologists in the referral and selection processes of candidates for transplantation in order to optimize the outcome of LT.

Lung transplantation in chronic obstructive pulmonary disease: patient selection and special considerations

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity. Lung transplantation is one of the few treatments available for end-stage COPD with the potential to improve survival and quality of life. The selection of candidates and timing of listing present challenges, as COPD tends to progress fairly slowly, and survival after lung transplantation remains limited. Though the natural course of COPD is difficult to predict, the use of assessments of functional status and multivariable indices such as the BODE index can help identify which patients with COPD are at increased risk for mortality, and hence which are more likely to benefit from lung transplantation. Patients with COPD can undergo either single or bilateral lung transplantation. Although many studies suggest better long-term survival with bilateral lung transplant, especially in younger patients, this continues to be debated, and definitive recommendations about this cannot be made. Patients may be more susceptible to particular complications of transplant for COPD, including native lung hyperinflation, and development of lung cancer.

Improving outcomes in chronic obstructive pulmonary disease: the role of the interprofessional approach

Chronic obstructive pulmonary disease (COPD) is associated with significant morbidity, places substantial time and cost burden on the health care system, and is now the third leading cause of death in the US. Many interventions are available to appropriately manage patients with COPD; however, fully implementing these strategies to help improve outcomes may be difficult. Collaboration between an interprofessional team of health care professionals (which includes physicians, nurses, respiratory therapists, physical therapists, dietitians, pharmacists, and many others) and COPD patients and caregivers is necessary to optimally manage these patients and to truly impact outcomes in this devastating disease. Prescribing evidence-based non-pharmacological and pharmacological therapies is an important start, but a true team-based approach is critical to successfully implement comprehensive care in patients with COPD. The goal of this review is to employ a case-based approach to provide practical information regarding the roles of the interprofessional team in implementing strategies to optimally manage COPD patients.

An Official American Thoracic Society/European Respiratory Society Statement: Research questions in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity, mortality, and resource use worldwide. The goal of this Official American Thoracic Society (ATS)/European Respiratory Society (ERS) Research Statement is to describe evidence related to diagnosis, assessment, and management; identify gaps in knowledge; and make recommendations for future research. It is not intended to provide clinical practice recommendations on COPD diagnosis and management.

METHODS

Clinicians, researchers, and patient advocates with expertise in COPD were invited to participate. A literature search of Medline was performed, and studies deemed relevant were selected. The search was not a systematic review of the evidence. Existing evidence was appraised and summarized, and then salient knowledge gaps were identified.

RESULTS

Recommendations for research that addresses important gaps in the evidence in all areas of COPD were formulated via discussion and consensus.

CONCLUSIONS

Great strides have been made in the diagnosis, assessment, and management of COPD as well as understanding its pathogenesis. Despite this, many important questions remain unanswered. This ATS/ERS Research Statement highlights the types of research that leading clinicians, researchers, and patient advocates believe will have the greatest impact on patient-centered outcomes.

An official American Thoracic Society/European Respiratory Society statement: research questions in COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity, mortality, and resource use worldwide. The goal of this official American Thoracic Society (ATS)/European Respiratory Society (ERS) research statement is to describe evidence related to diagnosis, assessment and management; identify gaps in knowledge; and make recommendations for future research. It is not intended to provide clinical practice recommendations on COPD diagnosis and management.

Clinicians, researchers, and patient advocates with expertise in COPD were invited to participate. A literature search of Medline was performed, and studies deemed relevant were selected. The search was not a systematic review of the evidence. Existing evidence was appraised and summarised, and then salient knowledge gaps were identified.

Recommendations for research that addresses important gaps in the evidence in all areas of COPD were formulatedviadiscussion and consensus.

Great strides have been made in the diagnosis, assessment and management of COPD, as well as understanding its pathogenesis. Despite this, many important questions remain unanswered. This ATS/ERS research statement highlights the types of research that leading clinicians, researchers, and patient advocates believe will have the greatest impact on patient-centred outcomes.

A consensus document for the selection of lung transplant candidates: 2014--an update from the Pulmonary Transplantation Council of the International Society for Heart and Lung Transplantation

The appropriate selection of lung transplant recipients is an important determinant of outcomes. This consensus document is an update of the recipient selection guidelines published in 2006. The Pulmonary Council of the International Society for Heart and Lung Transplantation (ISHLT) organized a Writing Committee of international experts to provide consensus opinion regarding the appropriate timing of referral and listing of candidates for lung transplantation. A comprehensive search of the medical literature was conducted with the assistance of a medical librarian. Writing Committee members were assigned specific topics to research and discuss. The Chairs of the Writing Committee were responsible for evaluating the completeness of the literature search, providing editorial support for the manuscript, and organizing group discussions regarding its content. The consensus document makes specific recommendations regarding the timing of referral and of listing for lung transplantation. These recommendations include discussions not present in previous ISHLT guidelines, including lung allocation scores, bridging to transplant with mechanical circulatory and ventilator support, and expanded indications for lung transplantation. In the absence of high-grade evidence to support decision making, these consensus guidelines remain part of a continuum of expert opinion based on available studies and personal experience. Some positions are immutable. Although transplant is rightly a treatment of last resort for end-stage lung disease, early referral allows proper evaluation and thorough patient education. Subsequent waiting list activation implies a tacit agreement that transplant offers a significant individual survival advantage. It is both the challenge and the responsibility of the transplant community globally to ensure organ allocation maximizes the potential benefits of a scarce resource, thereby achieving that advantage.

Lung transplantation assessment in a patient with COPD: a case study

This article focuses on the lung transplant assessment process for a patient with chronic obstructive pulmonary disease (COPD). It explains the investigations undertaken and their relevance in the context of transplantation. For a patient to be accepted onto the lung transplant waiting list, it is important to establish that their lung disease is severe enough to warrant transplantation, while ensuring that the patient is well enough to undergo the procedure with the potential for a good subsequent quality of life. The article also explores the importance of supportive care, symptom management and psychosocial assessment in potential lung transplant recipients.

Assessing the causal effect of organ transplantation on the distribution of residual lifetime

Because the number of patients waiting for organ transplants exceeds the number of organs available, a better understanding of how transplantation affects the distribution of residual lifetime is needed to improve organ allocation. However, there has been little work to assess the survival benefit of transplantation from a causal perspective. Previous methods developed to estimate the causal effects of treatment in the presence of time-varying confounders have assumed that treatment assignment was independent across patients, which is not true for organ transplantation. We develop a version of G-estimation that accounts for the fact that treatment assignment is not independent across individuals to estimate the parameters of a structural nested failure time model. We derive the asymptotic properties of our estimator and confirm through simulation studies that our method leads to valid inference of the effect of transplantation on the distribution of residual lifetime. We demonstrate our method on the survival benefit of lung transplantation using data from the United Network for Organ Sharing.

Role of exercise in testing and in therapy of COPD

The stair-climbing test, 6MWT, and shuttle test are exercise tests that requires less technical support than the CPET and are more available to any physician. The 6MWT is the simplest and most likely to be cost effective, as it provides useful information regarding prognosis, ADLs, and health care use at a very low cost. In addition, the 6MWT can be used to evaluate response to several interventions, including physical rehabilitation, medications, lung volume reduction interventions, and transplantation. The 6MWT has also been useful in and has become an integral part of the evaluation and response to treatment in other medical conditions, including congestive heart failure, pulmonary hypertension, and pulmonary fibrosis. The stair-climbing test seems to be most useful for preoperative evaluations when a CPET is not available. We have also used it on patients unable to perform a good CPET because of lack of familiarity with bicycle pedaling. The shuttle walk test may be used to better determine a maximal exercise capacity when a CPET is not available and to measure the effects of pulmonary rehabilitation in patients unfamiliar with a CPET. The role of exercise as a therapeutic tool is central to the concept of pulmonary rehabilitation. Exercise training improves not only functional dyspnea and health-related quality of life, but also has been shown to decrease health care resource use. As part of a comprehensive pulmonary rehabilitation initiated after a hospitalization for exacerbation, it has been shown to decrease readmission rates.

The management of asthma and chronic obstructive pulmonary disease: current status and future perspectives

Asthma and chronic obstructive pulmonary disease (COPD) represent the leading chronic respiratory diseases of interest in the word, owing to their high prevalence and burden on the health system. Care of these patients, undergoing frequent exacerbations, is a heavy burden on healthcare systems. In the last few years, large improvements in the management of asthma and COPD have been made, owing to new drugs and management strategies, and to the improvement of the nonpharmacologic treatment of COPD. There are still many unmet needs in the treatment of these diseases. In asthma, strategies to improve control should be implemented. There is a need to use more biomarkers to tailor treatment, in the assessment and choice of appropriate therapy, especially in severe patients. In COPD, there is growing evidence of individual differences in lung function decline rate and associated differences in appropriate management strategies. Early effective and prolonged bronchodilation can slow disease progression and reduce the frequency of exacerbations. New perspectives include the use of biologic drugs (anticytokine monoclonal antibodies) in selected categories of severe asthmatics, potential new inhibitors of chemokines and cytokines involved in the pathobiology of asthma and COPD, and a further improvement of current drugs and better implementation of management strategies, particularly in COPD patients.

Determinants of physical activity in daily life in candidates for lung transplantation

BACKGROUND

Participation in daily physical activity (PA) has never been objectively assessed in candidates for lung transplantation (LTx). The main research questions were: 1) How active are LTx-candidates in daily life? 2) What are determinants of activity behavior before LTX?

METHODS

Ninety-six candidates for LTx (diagnosis of COPD or interstitial lung disease; mean age 55 ± 7 years) underwent measurements of PA, pulmonary function, 6-min walking distance (6MWD), muscle force and health-status (SF-36 scale).

RESULTS

Patients were markedly inactive (5% of waking hours walking, 26% standing and 69% sedentary). Backward multiple regression identified 6MWD (expressed as % of predicted value; β = 73.0 steps, partial r(2) = 0.36, p = 0.00), a higher score on the energy/fatigue scale of the SF-36 (β = 28.6 steps, partial r(2) = 0.09, p = 0.00) and a higher expiratory muscle force (expressed as % of predicted value; β = 11.8 steps, partial r(2) = 0.05, p = 0.02) as determinants of daily steps. Minutes of mild to moderate (≥2 METs) activity were determined by 6MWD (expressed as % of predicted value; β = 2.14 min, partial r(2) = 0.30, p = 0.00), inspiratory muscle force (expressed as % of predicted value; β = 0.33 min, partial r(2) = 0.04, p = 0.05) and seasonal influences (spring/summer vs. autumn/winter: β = 18.95 min, partial r(2) = 0.04, p = 0.05). The overall fit of the models was r(2) = 0.50 and r(2) = 0.38, respectively.

CONCLUSIONS

The 6MWD was the main determinant of an inactive lifestyle in these patients. Respiratory muscle force, energy and fatigue and seasonal variations explained some additional variability in activity behavior. Patients should be encouraged to participate in interventions aimed at improving physical fitness and participation in daily physical activity before LTx.