Comparison of donor scores in bilateral lung transplantation-A large single-center analysis

Developing approaches to incorporate donor-lung computed tomography images into machine learning models to predict severe primary graft dysfunction after lung transplantation

Primary graft dysfunction (PGD) is a common complication after lung transplantation associated with poor outcomes. Although risk factors have been identified, the complex interactions between clinical variables affecting PGD risk are not well understood, which can complicate decisions about donor-lung acceptance. Previously, we developed a machine learning model to predict grade 3 PGD using donor and recipient electronic health record data, but it lacked granular information from donor-lung computed tomography (CT) scans, which are routinely assessed during offer review. In this study, we used a gated approach to determine optimal methods for analyzing donor-lung CT scans among patients receiving first-time, bilateral lung transplants at a single center over 10 years. We assessed 4 computer vision approaches and fused the best with electronic health record data at 3 points in the machine learning process. A total of 160 patients had donor-lung CT scans for analysis. The best imaging-only approach employed a 3D ResNet model, yielding median (interquartile range) areas under the receiver operating characteristic and precision-recall curves of 0.63 (0.49-0.72) and 0.48 (0.35-0.6), respectively. Combining imaging with clinical data using late fusion provided the highest performance, with median areas under the receiver operating characteristic and precision-recall curves of 0.74 (0.59-0.85) and 0.61 (0.47-0.72), respectively.

Impact of donor organ quality on recipient outcomes in lung transplantation: 14-Year single-center experience using the Eurotransplant lung donor score

Background

The use of extended-criteria donor (ECD) organs has increased in lung transplantation, but their impact on long-term outcomes remains unclear. This retrospective single-center study evaluates the impact of donor quality, as defined by the Eurotransplant (ET) lung donor score, on long-term graft function and survival.

Methods

Records of recipients transplanted between January 2010 and May 2023 were reviewed. Eurotransplant lung donor scores (ET scores) were retrospectively calculated from the corresponding donor reports. Outcomes were compared between recipients of donor lungs with an ET score of 6 (group 1), 7 and 8 (group 2), and 9 to 13 (group 3, ECD lungs). Median follow-up was 64 (30-104) months.

Results

In total, 280 (19%) patients were transplanted with ET score 6 lungs, 717 (48%) patients with ET scores 7 and 8 lungs, and 506 (34%) patients with ET scores 9 to 13 (ECD) lungs. The occurrence of primary graft dysfunction grade 3 at 72 hours (p = 0.672), duration of mechanical ventilation (p = 0.062), and in-hospital mortality (p = 0.713) did not differ between groups. Long-term graft survival (%) was lower in group 2 and 3 vs group 1 recipients (at 10 years: 51 and 48 vs 56, p = 0.052, respectively). Similarly, freedom from chronic lung allograft dysfunction (CLAD, %) was lower in group 2 and 3 vs group 1 recipients (at 10 years: 57 and 55 vs 63, p = 0.033, respectively). Donor smoking history was associated with worse CLAD-free survival (hazard ratio = 1.466, 95% confidence interval = 1.215-1.769, p < 0.001).

Conclusions

ECD lungs represented an important resource in lung transplantation. However, their use may be associated with a worse long-term graft and CLAD-free survival.

Development and validation of the lung donor (LUNDON) acceptability score for pulmonary transplantation

There is a chronic shortage of donor lungs for pulmonary transplantation due, in part, to low lung utilization rates in the United States. We performed a retrospective cohort study using data from the Scientific Registry of Transplant Recipients database (2006-2019) and developed the lung donor (LUNDON) acceptability score. A total of 83 219 brain-dead donors were included and were randomly divided into derivation (n = 58 314, 70%) and validation (n = 24 905, 30%) cohorts. The overall lung acceptance was 27.3% (n = 22 767). Donor factors associated with the lung acceptance were age, maximum creatinine, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen, mechanism of death by asphyxiation or drowning, history of cigarette use (≥20 pack-years), history of myocardial infarction, chest x-ray appearance, bloodstream infection, and the occurrence of cardiac arrest after brain death. The prediction model had high discriminatory power (C statistic, 0.891; 95% confidence interval, 0.886-0.895) in the validation cohort. We developed a web-based, user-friendly tool (available at https://sites.wustl.edu/lundon) that provides the predicted probability of donor lung acceptance. LUNDON score was also associated with recipient survival in patients with high lung allocation scores. In conclusion, the multivariable LUNDON score uses readily available donor characteristics to reliably predict lung acceptability. Widespread adoption of this model may standardize lung donor evaluation and improve lung utilization rates.

A Conceptual Model for Sources of Differential Selection in Lung Transplant Allocation

Rationale: In the United States, donor lungs are allocated to transplant candidates on the basis of lung allocation scores (LAS). However, additional factors beyond the LAS can impact who is transplanted, including listing and donor-organ acceptance practices. These factors can result in differential selection, undermining the objectivity of lung allocation. Yet their impact on the lung transplant pathway has been underexplored. Objectives: We sought to systematically examine sources of differential selection in lung transplantation via qualitative methods. Methods: We conducted semistructured qualitative interviews with lung transplant surgeons and pulmonologists in the United States between June 2019 and June 2020 to understand clinician perspectives on differential selection in lung transplantation and the LAS. Results: A total of 51 respondents (30 surgeons and 21 pulmonologists) identified many sources of differential selection arising throughout the pathway from referral to transplantation. We synthesized these sources into a conceptual model with five themes: 1) transplant center's degree of risk tolerance and accountability; 2) successfulness and fairness of the LAS; 3) donor-organ availability and regional competition; 4) patient health versus program health; and 5) access to care versus responsible stewardship of organs. Conclusions: Our conceptual model demonstrates how differential selection can arise throughout lung transplantation and facilitates the further study of such selection. As new organ allocation models are developed, differential selection should be considered carefully to ensure that these models are more equitable.

The Impact of New Treatments on Short- and MID-Term Outcomes in Bilateral Lung Transplant: A Propensity Score Study

BACKGROUND

Despite many efforts to improve organ preservation and recipient survival, overall lung transplant (LT) mortality is still high. We aimed to investigate the impact of 'prophylactic' veno-arterial extracorporeal membrane oxygenation (VA ECMO) and tacrolimus on 72-h primary graft dysfunction (PGD) and 30-day acute cellular rejection, respectively.

METHODS

All consecutive LT patients admitted to the Intensive Care Unit of the Padua University Hospital (February, 2016-2022) were screened. Only adult patients undergoing first bilateral LT and not requiring cardio-pulmonary bypass, invasive mechanical ventilation, and/or ECMO before LT, were included. A propensity score weighting analysis was employed to account for the non-random allocation of the subjects to different treatments.

RESULTS

A total of 128 LT recipients were enrolled. Compared to the 'off-pump'-group (n.47, 37%), 'prophylactic' VA ECMO (n.51,40%) recorded similar 72-h PGD values, perioperative blood products and lower acute kidney dysfunction. Compared with cyclosporine (n.86, 67%), tacrolimus (n.42, 33%) recorded a lower risk of 30-day cellular rejection, kidney dysfunction, and bacteria isolation.

CONCLUSIONS

'Prophylactic' VA ECMO recorded 72-h PGD values comparable to the 'off-pump'-group; while tacrolimus showed a lower incidence of 30-day acute cellular rejection.

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.