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

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.

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.

Determinants of survival after lung transplantation in telomerase-related gene mutation carriers: A retrospective cohort

Carriers of germline telomerase-related gene (TRG) mutations can show poor prognosis, with an increase in common hematological complications after lung transplantation (LT) for pulmonary fibrosis. The aim of this study was to describe the outcomes after LT in recipients carrying a germline TRG mutation and to identify the predictors of survival. In a multicenter cohort of LT patients, we retrospectively reviewed those carrying pathogenic TRG variations (n = 38; TERT, n = 23, TERC, n = 9, RTEL1, n = 6) between 2009 and 2018. The median age at LT was 54 years (interquartile range [IQR] 46-59); 68% were male and 71% had idiopathic pulmonary fibrosis. During the diagnosis of pulmonary fibrosis, 28 (74%) had a hematological disease, including eight with myelodysplasia. After a median follow-up of 26 months (IQR 15-46), 38 patients received LT. The overall post-LT median survival was 3.75 years (IQR 1.8-NA). The risk of death after LT was increased for patients with myelodysplasia (HR 4.1 [95% CI 1.5-11.5]) or short telomere (HR 2.2 [1.0-5.0]) before LT. After LT, all patients had anemia, 66% had thrombocytopenia, and 39% had neutropenia. Chronic lung allograft dysfunction frequency was 29% at 4 years. The present findings support the use of LT in TRG mutation carriers without myelodysplasia. Hematological evaluation should be systematically performed before LT.

Lung transplantation for acute respiratory distress syndrome - a retrospective European Cohort Study

BACKGROUND

The published experience of lung transplantation (LTX) in acute respiratory distress syndrome (ARDS) is limited. The aim of this study was to investigate the contemporary results of LTX attempts in ARDS in major European centers.

METHODS

We conducted a retrospective multicenter cohort study of all patients listed for LTX between 2011 and 2019. We surveyed 68 centers in 22 European countries. All patients admitted to the waitlist for lung transplantation with a diagnosis of "ARDS//pneumonia" were included. Patients without extracorporeal membrane oxygenation (ECMO) or mechanical ventilation were excluded. Patients were followed until October 1st 2020 or death. Multivariable analysis for 1-year survival after listing and lung transplantation were performed.

RESULTS

Forty-eight centers (74%) with a total transplant activity of 12 438 lung transplants during the 9-year period gave feedback. Forty patients with a median age of 35 years were identified. Patients were listed for LTX in 18 different centers in 10 countries. Thirty-one-patients underwent LTX (0·25% of all indications) and 9 patients died on the waitlist. Ninety percent of transplanted patients were on ECMO in combination with mechanical ventilation before LTX. On multivariable analysis, transplantation during 2015 until 2019 was independently associated with better 1-year survival after LTX (odds ratio 10.493, 95% CI 1.977, 55.705, p=0.006). Sixteen survivors out of 23 patients with known status (70%) returned to work after LTX.

CONCLUSION

LTX in highly selected ARDS patients is feasible and outcome has improved in the modern era. The selection process remains ethically and technically challenging.

The Surplus Transplant Lung Allocation System in Italy: An Evaluation of the Allocation Process via Stochastic Modeling

Background: Lung transplantation is a specialized procedure used to treat chronic end-stage respiratory diseases. Due to the scarcity of lung donors, constructing fair and equitable lung transplant allocation methods is an issue that has been addressed with different strategies worldwide. This work aims to describe how Italy’s “national protocol for the management of surplus organs in all transplant programs” functions through an online app to allocate lung transplants. We have developed two probability models to describe the allocation process among the various transplant centers. An online app was then created. The first model considers conditional probabilities based on a protocol flowchart to compute the probability for each area and transplant center to receive each n-th organ in the period considered. The second probability model is based on the generalization of the binomial distribution to correlated binary variables, which is based on Bahadur’s representation, to compute the cumulative probability for each transplant center to receive at least nth organs. Our results show that the impact of the allocation of a surplus organ depends mostly on the region where the organ was donated. The discrepancies shown by our model may be explained by a discrepancy between the northern and southern regions in relation to the number of organs donated.

The impact of the high emergency lung transplantation program in cystic fibrosis in France: insight from a comparison with Canada

INTRODUCTION

France implemented a high emergency lung transplantation (HELT) program nationally in 2007. A similar program does not exist in Canada. The objectives of our study were to compare health outcomes within France as well as between Canada and France before and after the HELT program in a population with Cystic Fibrosis (CF).

METHODS

This population-based cohort study utilised data from the French and Canadian CF registries. A cumulative incidence curve assessed time to transplant with death without transplant as competing risks. The Kaplan-Meier method was used to estimate post-transplant survival.

RESULTS

Between 2002 and 2016, there were 1075 (13.0%) people with CF in France and 555 (10.2%) people with CF in Canada who underwent lung transplantation. The proportion of lung transplant increased in France after the HELT program was initiated (4.5% versus 10.1%) whereas deaths pre-transplant decreased from 85.3% in the pre-HELT to 57.1% in the post-HELT period. Between 2008-2016, people in France were significantly more likely to receive a transplant (Hazard Ratio (HR) 1.56, 95% CI 1.37-1.77, p<0.001) than die (HR 0.55, 95% CI 0.46-0.66, p<0.001) compared to Canada. Post-transplant survival was similar between the countries and there was no difference in survival when comparing pre- and post-HELT period in France.

CONCLUSION

Following the implementation of the HELT program, people living with CF in France were more likely to receive a transplant than die. Post-transplant survival in the post-HELT period in France did not change compared to the pre-HELT period, despite potentially sicker patients being transplanted, and is comparable to Canada.

Developments in lung transplantation over the past decade

With an improved median survival of 6.2 years, lung transplantation has become an increasingly acceptable treatment option for end-stage lung disease. Besides survival benefit, improvement of quality of life is achieved in the vast majority of patients. Many developments have taken place in the field of lung transplantation over the past decade. Broadened indication criteria and bridging techniques for patients awaiting lung transplantation have led to increased waiting lists and changes in allocation schemes worldwide. Moreover, the use of previously unacceptable donor lungs for lung transplantation has increased, with donations from donors after cardiac death, donors with increasing age and donors with positive smoking status extending the donor pool substantially. Use of ex vivo lung perfusion further increased the number of lungs suitable for lung transplantation. Nonetheless, the use of these previously unacceptable lungs did not have detrimental effects on survival and long-term graft outcomes, and has decreased waiting list mortality. To further improve long-term outcomes, strategies have been proposed to modify chronic lung allograft dysfunction progression and minimise toxic immunosuppressive effects. This review summarises the developments in clinical lung transplantation over the past decade.

Lung allocation for transplant: The European perspective

Since the first successful lung transplants in humans were done in the 1980s, lung transplantation has become an established treatment for end-stage pulmonary disease. Because the access to transplantable organs is limited and unpredictable, rules that guide the allocation of lungs for transplants have emerged. Such rules are governed not only by medical and bioethical necessities, but also by local traditions, legislation, and practical circumstances. Therefore, there may be significant differences between the organ allocation practices in various parts of the world. In this brief communication, the European perspective on lung allocation is presented, also adding a very brief description of other parts of the world.