Clinical Outcomes of Lung Transplants From Donors With Unexpected Pulmonary Embolism

Utilizing lung donors with recent massive pulmonary emboli and chronic thromboembolic disease for transplantation

Organ availability remains a persistent problem in lung transplantation. The use of organs from donors with chronic thromboembolic disease has not been described. In this report, we discuss 2 lung transplant recipients who received organs from donors with acute bilateral pulmonary embolism. All organs underwent backtable pulmonary thromboendarterectomy before implantation and notably showed evidence of chronic thromboembolic disease and subacute changes in the distal vasculature. Grafts were placed with both patients on venoarterial extracorporeal membrane oxygenation. Both patients had unremarkable hospital courses with graft dysfunction scores of 0 at 48 and 72 hours. At follow-up, both patients remained free of graft rejection. We highlight the utility of lungs derived from chronic thromboembolic disease as a strategy to expand the organ pool.

Pulmonary Embolism in Donor Lungs-Incidence and Management

In efforts to decrease the mortality on the waiting list for lung transplantation, alternatives to increase the donor pool have been explored. Caution must be used when accepting donor lungs with pulmonary embolism (PE), as prior evidence has shown mixed results after transplantation of donor lungs with PE. However, the mere diagnosis of PE on imaging should not be the sole reason for the exclusion of these donors for transplant, and they should be reviewed as any other donor. A comprehensive evaluation should be performed for every donor, with a special focus on abnormalities of gas exchange and gross pathologic characteristics during procurement.

Pulmonary Embolism Following Lung Transplantation: Prevention and Management

Thromboembolic events are the third leading cardiovascular diagnosis following stroke and myocardial infarction. In the United States, 300,000 to 600,000 people per year are diagnosed with venous thromboembolism, either deep venous thrombosis or pulmonary embolism (PE). Of those patients, thousands die from PE despite heightened vigilance and improved therapies. Lung transplant recipients are at increased risk of developing PE due to multiple risk factors unique to this population. Additionally, the transplant recipients are more susceptible to morbid complications from PE. As a result, prevention, timely recognition, and intervention of PE in the lung transplant population are of the utmost importance.

Alterations in Pulmonary Physiology with Lung Transplantation

Lung transplant is a treatment option for patients with end-stage lung diseases; however, survival outcomes continue to be inferior when compared to other solid organs. We review the several anatomic and physiologic changes that result from lung transplantation surgery, and their role in the pathophysiology of common complications encountered by lung recipients. The loss of bronchial circulation into the allograft after transplant surgery results in ischemia-related changes in the bronchial artery territory of the allograft. We discuss the role of bronchopulmonary anastomosis in blood circulation in the allograft posttransplant. We review commonly encountered complications related to loss of bronchial circulation such as allograft airway ischemia, necrosis, anastomotic dehiscence, mucociliary dysfunction, and bronchial stenosis. Loss of dual circulation to the lung also increases the risk of pulmonary infarction with acute pulmonary embolism. The loss of lymphatic drainage during transplant surgery also impairs the management of allograft interstitial fluid, resulting in pulmonary edema and early pleural effusion. We discuss the role of lymphatic drainage in primary graft dysfunction. Besides, we review the association of late posttransplant pleural effusion with complications such as acute rejection. We then review the impact of loss of afferent and efferent innervation from the allograft on control of breathing, as well as lung protective reflexes. We conclude with discussion about pulmonary function testing, allograft monitoring with spirometry, and classification of chronic lung allograft dysfunction phenotypes based on total lung capacity measurements. We also review factors limiting physical exercise capacity after lung transplantation, especially impairment of muscle metabolism. © 2023 American Physiological Society. Compr Physiol 13:4269-4293, 2023.

Lungs From Donors ≥70 Years of Age for Transplantation-Do Long-Term Outcomes Justify Their Use?

Donor shortages have led transplant centers to extend their criteria for lung donors. Accepting lung donors ≥70 years of age has previously shown good short-term outcomes; however, no mid- and long-term outcome data on these extended criteria donors has been published to date. In this study, all patients who underwent lung transplantation between 06/2010 and 12/2019 were included in the analysis, and the outcomes were compared between patients receiving organs from donors <70 years of age and patients transplanted with lungs from donors ≥70 years of age. Among the 1,168 lung-transplanted patients, 62 patients received lungs from donors ≥70 years of age. The recipient age of those receiving older organs was significantly higher, and they were more likely to suffer from obstructive lung disease. Older donors were exposed to significantly shorter periods of mechanical ventilation prior to donation, had higher Horowitz indices, and were less likely to have smoked. The postoperative time on mechanical ventilation, time on ICU, and total hospital stay were comparable. The overall survival as well as CLAD-free survival showed no differences between both groups in the follow-up period. Utilization of lungs from donors ≥70 years of age leads to excellent mid- and long-term results that are similar to organs from younger donors when the organs from older donors are carefully preselected.

Exploring predisposing factors and pathogenesis contributing to injuries of donor lungs

INTRODUCTION

Lung transplantation (LTx) remains the only therapeutic strategy for patients with incurable lung diseases. However, its use has been severely limited by the narrow donor pool and potential concerns of inferior quality of donor lungs, which are more susceptible to external influence than other transplant organs. Multiple insults, including various causes of death and a series of perimortem events, may act together on donor lungs and eventually culminate in primary graft dysfunction (PGD) after transplantation as well as other poor short-term outcomes.

AREAS COVERED

This review focuses on the predisposing factors contributing to injuries to the donor lungs, specifically focusing on the pathogenesis of these injuries and their impact on post-transplant outcomes. Additionally, various maneuvers to mitigate donor lung injuries have been proposed.

EXPERT OPINION

The selection criteria for eligible donors vary and may be poor discriminators of lung injury. Not all transplanted lungs are in ideal condition. With the rapidly increasing waiting list for LTx, the trend of using marginal donors has become more apparent, underscoring the need to gain a deeper understanding of donor lung injuries and discover more donor resources.

The Year in Cardiothoracic Transplant Anesthesia: Selected Highlights From 2020 Part I - Lung Transplantation

This special article focuses on the highlights in cardiothoracic transplantation literature in the year 2020. Part I encompasses the recent literature on lung transplantation, including the advances in preoperative assessment and optimization, donor management, including the use of ex-vivo lung perfusion, recipient management, including those who have been infected with coronavirus disease 2019, updates on the perioperative management, including the use of extracorporeal membrane oxygenation, and long-term outcomes.