Survival outcomes following urgent lung transplantation in France and the USA.

INTRODUCTION: Lung graft allocation can be based on a score (Lung Allocation Score) as in the USA or sequential proposals combined with a discrete priority model as in France. We aimed to analyse the impact of allocation policy on the outcome of urgent lung transplantation (LT). METHODS: US United Network for Organ Sharing (UNOS) and French Cristal databases were retrospectively reviewed to analyse LT performed between 2007 and 2017. We analysed the mortality risk of urgent LT by fitting Cox models and adjusted Restricted Mean Survival Time. We then compared the outcome after urgent LT in the UNOS and Cristal groups using a propensity score matching. RESULTS: After exclusion of patients with chronic obstructive pulmonary disease/emphysema and redo LT, 3775 and 12 561 patients underwent urgent LT and non-urgent LT in the USA while 600 and 2071 patients underwent urgent LT and non-urgent LT in France. In univariate analysis, urgent LT was associated with an HR for death of 1.24 (95% CI 1.05 to 1.48) in the Cristal group and 1.12 (95% CI 1.05 to 1.19) in the UNOS group. In multivariate analysis, the effect of urgent LT was attenuated and no longer statistically significant in the Cristal database (HR 1.1 (95% CI 0.91 to 1.33)) while it remained constant and statistically significant in the UNOS database (HR 1.12 (95% CI 1.05 to 1.2)). Survival comparison of urgent LT patients between the two countries was significantly different in favour of the UNOS group (1-year survival rates 84.1% (80.9%-87.3%) vs 75.4% (71.8%-79.1%) and 3-year survival rates 66.3% (61.9%-71.1%) vs 62.7% (58.5%-67.1%), respectively). CONCLUSION: Urgent LT is associated with adverse outcome in the USA and in France with a better prognosis in the US score-based system taking post-transplant survival into account. This difference between two healthcare systems is multifactorial.

Protocol for venoarterial ExtraCorporeal Membrane Oxygenation to reduce morbidity and mortality following bilateral lung TransPlantation: the ECMOToP randomised controlled trial.

INTRODUCTION: Lung transplantation (LTx) aims at improving survival and quality of life for patients with end-stage lung diseases. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is used as intraoperative support for LTx, despite no precise guidelines for its initiation. We aim to evaluate two strategies of VA-ECMO initiation in the perioperative period in patients with obstructive or restrictive lung disease requiring bilateral LTx. In the control 'on-demand' arm, high haemodynamic and respiratory needs will dictate VA-ECMO initiation; in the experimental 'systematic' arm, VA-ECMO will be pre-emptively initiated. We hypothesise a 'systematic' strategy will increase the number of ventilatory-free days at day 28. METHODS AND ANALYSIS: We designed a multicentre randomised controlled trial in parallel groups. Adult patients with obstructive or restrictive lung disease requiring bilateral LTx, without a formal indication for pre-emptive VA-ECMO before LTx, will be included. Patients with preoperative pulmonary hypertension with haemodynamic collapse, ECMO as a bridge to transplantation, severe hypoxaemia or hypercarbia will be secondarily excluded. In the systematic group, VA-ECMO will be systematically implanted before the first pulmonary artery cross-clamp. In the on-demand group, VA-ECMO will be implanted intraoperatively if haemodynamic or respiratory indices meet preplanned criteria. Non-inclusion, secondary exclusion and VA-ECMO initiation criteria were validated by a Delphi process among investigators. Postoperative weaning of ECMO and mechanical ventilation will be managed according to best practice guidelines. The number of ventilator-free days at 28 days (primary endpoint) will be compared between the two groups in the intention-to-treat population. Secondary endpoints encompass organ failure occurrence, day 28, day 90 and year 1 vital status, and adverse events. ETHICS AND DISSEMINATION: The sponsor is the Assistance Publique-Hôpitaux de Paris. The ECMOToP protocol version 2.1 was approved by Comité de Protection des Personnes Ile de France VIII. Results will be published in international peer-reviewed medical journals. TRIAL REGISTRATION NUMBER: NCT05664204.

Incidence and risk factors of anastomotic complications after lung transplantation.

BACKGROUND: Anastomotic complications are common after lung transplantation (1.4-33% of cases) and still associated with a high morbi-mortality. METHODS: The current study is a monocenter retrospective analysis of symptomatic anastomotic complications (SAC) occurring after lung transplantation between 2010 and 2016, using the macroscopic, diameter, and suture (M-D-S) classification from consensus of French experts in bronchoscopy. The objectives were to determine incidence from surgery, risk factors, and impact of survival of SAC. We defined SAC as M-D-S abnormalities (stenosis ⩾ 50% or dehiscence) requiring bronchoscopic or surgical interventions. RESULTS: A total of 121 patients were included. SAC occurred in 26.5% of patients (n = 32), divided in symptomatic stenosis for 23.7% (n = 29), and symptomatic dehiscence in 2.5% (n = 3). In multivariate analysis, donor bacterial lung infection [HR 2.08 (1.04-4.17), p = 0.04] and age above 50 years [HR 3.26 (1.04-10.26), p = 0.04] were associated with SAC occurrence. Cystic fibrosis etiology was associated with better survival on Kaplan-Meier curve (p < 0.001). SAC [HR 2.15 (1.07-4.32), p = 0.03] was independently associated with worst survival. The 29 symptomatic patients because of stenosis required endoscopic procedure, of whom 16 patients needed bronchial stent placement. Four patients underwent surgery: three patients because of dehiscence and one because of severe bilateral stenosis (re-transplantation). DISCUSSION: SAC occurred in 26.5% of patients. Donor lung infection was the only alterable identified factors. The increase rate of SAC in older patients above 50 years of age encourages in regular endoscopic monitoring.

Superior vena cava graft infection in thoracic surgery: a retrospective study of the French EPITHOR database.

OBJECTIVES: To report our experience on the management of superior vena cava graft infection. METHODS: Between 2001 and 2018, patients with superior vena cava synthetic graft or patch reconstruction after resection of intrathoracic tumours or benign disease were selected retrospectively from the French EPITHOR database and participating thoracic centres. Our study population includes patients with superior vena cava graft infection, defined according to the MAGIC consensus. Superior vena cava synthetic grafts in an empyema or mediastinitis were considered as infected. RESULTS: Of 111 eligible patients, superior vena cava graft infection occurred in 12 (11.9%) patients with a polytetrafluoroethylene graft secondary to contiguous contamination. Management consisted of either conservative treatment with chest tube drainage and antibiotics (n = 3) or a surgical graft-sparing strategy (n = 9). Recurrence of infection appears in 6 patients. Graft removal was performed in 2 patients among the 5 reoperated patients. The operative mortality rate was 25%. CONCLUSIONS: Superior vena cava graft infection may develop as a surgical site infection secondary to early mediastinitis or empyema. Graft removal is not always mandatory but should be considered in late or recurrent graft infection or in infections caused by aggressive microorganisms (virulent or multidrug resistant bacteria or fungi).

Celsior® crystalloid cardioplegia versus standard hyperkalemic normothermic blood cardioplegia: Analysis of myocardial protection in elective mitral valve repair.

INTRODUCTION: With the increase and refinement of video assisted mitral valve surgery, cristalloïd cardioplegia started regaining popularity. The aim of our study was to evaluate the effectiveness of Celsior®, a crystalloid cardioplegic solution, on myocardial protection in elective surgical mitral valve repair in comparison to blood based hyperkalemic cardioplegia. METHODS: In this observational retrospective study, all consecutive elective isolated surgical mitral valve repair where Celsior® or normothermic hyperkalemic blood cardioplegia were used were included. Primary endpoint was any sign of myocardial protection failure (troponin levels, need for inotropic or mechanical support, rhythm disturbances, mortality). Secondary endpoint was Celsior® safety (allergic reactions, bleeding, organ toxicities). RESULTS: From January 2009 to August 2016, 382 patients underwent elective isolated mitral valve repair in whom normothermic hyperkalemic blood cardioplegia (n = 181) or Celsior® (n = 201) were used. There were no statistically significant differences in baseline characteristics including Euroscore 2. Peak troponin (pg/ml) release and 30-days mortality were not statistically different. Need for cardioversion was significantly more frequent in the Celsior® group (47% vs 13%, p < 0.001). There was no statistical difference in post-operative atrial fibrillation, permanent pacemaker implantation, reoperation for bleeding, transfusion, acute kidney injury, haemoglobin at discharge or length of stay. No allergic reaction to Celsior® occurred. CONCLUSION: Effective myocardial protection was achieved with the Celsior® cardioplegic solution with no unexpected toxicity. Celsior® may be an efficacious and safe cardioprotective strategy in mitral valve repair.

A heart transplant after total artificial heart support: initial and long-term results.

OBJECTIVES: At our centre, the SynCardia temporary Total Artificial Heart (TAH-t) (SynCardia Systems, LLC, Tucson, AZ, USA) is used to provide long-term support for patients with biventricular failure as a bridge to a transplant. However, a heart transplant (HT) after such support remains challenging. The aim of this retrospective study was to assess the immediate and long-term results following an HT in the cohort of patients who had a TAH-t implant. METHODS: A total of 73 patients were implanted with the TAH-t between 1988 and 2019 in our centre. Of these 73 consecutive patients, 50 (68%) received an HT and are included in this retrospective analysis of prospectively collected data. RESULTS: In the selected cohort, in-hospital mortality after an HT was 10% (n = 5). The median intensive care unit stay was 33 days (range 5-278). The median hospital stay was 41 days (range 28-650). A partial or total pericardiectomy was performed during the HT procedure in 21 patients (42%) due to a severe pericardial reaction. Long-term survival rates after an HT at 5, 10 and 12 years were 79.1 ± 5.9% (n = 32), 76.5 ± 6.3% (n = 22) and 72.4 ± 7.1% (n = 12), respectively, which was similar to the long-term survival for a primary HT without TAH-t during the same period (n = 686). An HT performed within 3-6 months post-TAH-t implantation appeared to provide the best survival (P = 0.007). Eight (16%) patients required chronic dialysis during the subsequent follow-up period, with 3 patients requiring a kidney transplant. CONCLUSIONS: The long-term outcomes with the SynCardia TAH-t as a bridge to transplant in patients with severe biventricular failure are very encouraging. Our review noted that an HT following TAH-t can be technically challenging, especially in the case of a severe pericardial reaction, with potential pitfalls that should be recognized preoperatively.

Impact of donor, recipient and matching on survival after high emergency lung transplantation in France.

INTRODUCTION: Since July 2007, the French high emergency lung transplantation (HELT) allocation procedure prioritises available lung grafts to waiting patients with imminent risk of death. The relative impacts of donor, recipient and matching on the outcome following HELT remain unknown. We aimed at deciphering the relative impacts of donor, recipient and matching on the outcome following HELT in an exhaustive administrative database. METHODS: All lung transplantations performed in France were prospectively registered in an administrative database. We retrospectively reviewed the procedures performed between July 2007 and December 2015, and analysed the impact of donor, recipient and matching on overall survival after the HELT procedure by fitting marginal Cox models. RESULTS: During the study period, 2335 patients underwent lung transplantation in 11 French centres. After exclusion of patients with chronic obstructive pulmonary disease/emphysema, 1544 patients were included: 503 HELT and 1041 standard lung transplantation allocations. HELT was associated with a hazard ratio for death of 1.41 (95% CI 1.22-1.64; p<0.0001) in univariate analysis, decreasing to 1.32 (95% CI 1.10-1.60) after inclusion of recipient characteristics in a multivariate model. A donor score computed to predict long-term survival was significantly different between the HELT and standard lung transplantation groups (p=0.014). However, the addition of donor characteristics to recipient characteristics in the multivariate model did not change the hazard ratio associated with HELT. CONCLUSIONS: This exhaustive French national study suggests that HELT is associated with an adverse outcome compared with regular allocation. This adverse outcome is mainly related to the severity status of the recipients rather than donor or matching characteristics.

Blood CD9+ B cell, a biomarker of bronchiolitis obliterans syndrome after lung transplantation.

Bronchiolitis obliterans syndrome is the main limitation for long-term survival after lung transplantation. Some specific B cell populations are associated with long-term graft acceptance. We aimed to monitor the B cell profile during early development of bronchiolitis obliterans syndrome after lung transplantation. The B cell longitudinal profile was analyzed in peripheral blood mononuclear cells from patients with bronchiolitis obliterans syndrome and patients who remained stable over 3 years of follow-up. CD24hi CD38hi transitional B cells were increased in stable patients only, and reached a peak 24 months after transplantation, whereas they remained unchanged in patients who developed a bronchiolitis obliterans syndrome. These CD24hi CD38hi transitional B cells specifically secrete IL-10 and express CD9. Thus, patients with a total CD9+ B cell frequency below 6.6% displayed significantly higher incidence of bronchiolitis obliterans syndrome (AUC = 0.836, PPV = 0.75, NPV = 1). These data are the first to associate IL-10-secreting CD24hi CD38hi transitional B cells expressing CD9 with better allograft outcome in lung transplant recipients. CD9-expressing B cells appear as a contributor to a favorable environment essential for the maintenance of long-term stable graft function and as a new predictive biomarker of bronchiolitis obliterans syndrome-free survival.

High circulating CD4+CD25hiFOXP3+ T-cell sub-population early after lung transplantation is associated with development of bronchiolitis obliterans syndrome.

BACKGROUND: Chronic bronchiolitis obliterans syndrome (BOS) remains a major limitation for long-term survival after lung transplantation. The immune mechanisms involved and predictive biomarkers have yet to be identified. The purpose of this study was to determine whether peripheral blood T-lymphocyte profile could predict BOS in lung transplant recipients. METHODS: An in-depth profiling of CD4+ and CD8+ T cells was prospectively performed on blood cells from stable (STA) and BOS patients with a longitudinal follow-up. Samples were analyzed at 1 and 6 months after transplantation, at the time of BOS diagnosis, and at an intermediate time-point at 6 to 12 months before BOS diagnosis. RESULTS: Although no significant difference was found for T-cell compartments at BOS diagnosis or several months beforehand, we identified an increase in the CD4+CD25hiFoxP3+ T-cell sub-population in BOS patients at 1 and 6 months after transplantation (3.39 ± 0.40% vs 1.67 ± 0.22% in STA, p < 0.001). A CD4+CD25hiFoxP3+ T-cell threshold of 2.4% discriminated BOS and stable patients at 1 month post-transplantation. This was validated on a second set of patients at 6 months post-transplantation. Patients with a proportion of CD4+CD25hiFoxP3+ T cells up to 2.4% in the 6 months after transplantation had a 2-fold higher risk of developing BOS. CONCLUSIONS: This study is the first to report an increased proportion of circulating CD4+CD25hiFoxP3+ T cells early post-transplantation in lung recipients who proceed to develop BOS within 3 years, which supports its use as a BOS predictive biomarker.

Blood Gene Expression Predicts Bronchiolitis Obliterans Syndrome.

Bronchiolitis obliterans syndrome (BOS), the main manifestation of chronic lung allograft dysfunction, leads to poor long-term survival after lung transplantation. Identifying predictors of BOS is essential to prevent the progression of dysfunction before irreversible damage occurs. By using a large set of 107 samples from lung recipients, we performed microarray gene expression profiling of whole blood to identify early biomarkers of BOS, including samples from 49 patients with stable function for at least 3 years, 32 samples collected at least 6 months before BOS diagnosis (prediction group), and 26 samples at or after BOS diagnosis (diagnosis group). An independent set from 25 lung recipients was used for validation by quantitative PCR (13 stables, 11 in the prediction group, and 8 in the diagnosis group). We identified 50 transcripts differentially expressed between stable and BOS recipients. Three genes, namely POU class 2 associating factor 1 (POU2AF1), T-cell leukemia/lymphoma protein 1A (TCL1A), and B cell lymphocyte kinase, were validated as predictive biomarkers of BOS more than 6 months before diagnosis, with areas under the curve of 0.83, 0.77, and 0.78 respectively. These genes allow stratification based on BOS risk (log-rank test p < 0.01) and are not associated with time posttransplantation. This is the first published large-scale gene expression analysis of blood after lung transplantation. The three-gene blood signature could provide clinicians with new tools to improve follow-up and adapt treatment of patients likely to develop BOS.

Tissue remodelling in chronic bronchial diseases: from the epithelial to mesenchymal phenotype.

Airway remodelling is a critical feature of chronic bronchial diseases, characterised by aberrant repair of the epithelium and accumulation of fibroblasts, which contribute to extracellular matrix (ECM) deposition resulting in fixed bronchial obstruction. Recently, epithelial-mesenchymal transition (EMT) has been identified as a new source of fibroblasts that could contribute to the remodelling of the airways. This phenomenon consists of the loss of the epithelial phenotype by bronchial epithelial cells and the acquisition of a mesenchymal phenotype. These cells are then able to migrate and secrete ECM molecules. Herein, we review the different types of EMT. We will then focus on the signalling pathways that are involved, such as transforming growth factor-ß and Wnt, as well as the more recently described Sonic Hedgehog pathway. Finally, we will highlight the implication of EMT in airway remodelling in specific chronic bronchial pathologies, such as asthma, chronic obstructive pulmonary disease and bronchiolitis obliterans following lung transplantation. Despite the limitations of in vitro models, future studies of EMT in vivo are warranted to shed new light on the pathomechanisms of bronchial obstruction.