Trends in marginal lung allograft survival: Advanced‐age donors improve

Abstract

Introduction Although lung demand continues to outpace supply, 75% of potential donor lungs are discarded without being transplanted in the United States. To identify the discarded cohorts best suited to alleviate the lung shortage and reduce waitlist mortality, we explored changes in survival over time for five marginal donor definitions: age >60 years, smoking history >20 pack‐years, PaO2/FiO2 < 300 mmHg, purulent bronchoscopic secretions, and chest radiograph infiltrates. Methods Our retrospective cohort study separated 27 803 lung recipients in the UNOS Database into three 5‐year eras by transplant date: 2005–2009, 2010–2014, and 2015–2019. Multivariable Cox proportional hazards regression and Kaplan‐Meier analysis with log‐rank test were used to compare survival across the eras. Results Three definitions—low PaO2/FiO2, purulent bronchoscopic secretions, and abnormal chest radiographs—did not bear out as truly marginal, demonstrating lack of significantly elevated risk. Advanced donor age demonstrated considerable survival improvement (HR (95% CI): 1.47 (1.26–1.72) in 2005–2009 down to 1.14 (.97–1.35) for 2015–2019), with protective factors being recipients <60 years, moderate recipient BMI, and low Lung Allocation Score (LAS). Donors with smoking history failed to demonstrate any significant improvement (HR (95% CI): 1.09 (1.01–1.17) in 2005–2009 increasing to 1.22 (1.08–1.38) in 2015–2019). Conclusions Advanced donor age, previously the most significant risk factor, has improved to near‐benchmark levels, demonstrating the possibility for matching older donors to healthier non‐elderly recipients in selected circumstances. Low PaO2/FiO2, bronchoscopic secretions, and abnormal radiographs demonstrated survival on par with standard donors. Significant donor smoking history, a moderate risk factor, has failed to improve.

Lung Transplant Outcome From Selected Older Donors (≥70 Years) Equals Younger Donors (<70 Years)

“…Extension of conservative standard donor criteria is generally accepted, and graft acceptability is now pushed by emerging strategies like the use of DCD and elderly donors 12 . Despite potential risks, the use of these elderly grafts is justified in view of the increased waiting-list mortality and their better outcome compared with offering no transplantation 13,14 . In comparison to North America, European organ donors are older, with higher ratios of DCD (due to lower numbers of head trauma, provoked by gun violence, or homicide).…”

“…Therefore, old(er) donors are becoming more promising whereas they were previously disqualified based on age alone. In this regard, it might be advisable to no longer recommend any particular upper age limit for lung donors 14 …”

“…In this regard, it might be advisable to no longer recommend any particular upper age limit for lung donors. 14 Due to senescence mechanisms, older organs in general show less functional reserve, greater susceptibility to organ damage, and reduced repair capacity. As an example, we hypothesized that more calcified older bronchi could result in longer anastomosis times and more anastomotic problems.…”

“… 12 Despite potential risks, the use of these elderly grafts is justified in view of the increased waiting-list mortality and their better outcome compared with offering no transplantation. 13 , 14 In comparison to North America, European organ donors are older, with higher ratios of DCD (due to lower numbers of head trauma, provoked by gun violence, or homicide). In a recent analysis from 2020, the median donor age across European transplant centers was 51 years compared with 33 years in North America.…”

“…In this regard, it might be advisable to no longer recommend any particular upper age limit for lung donors. 14 …”