North American expert consensus on the clinical role of ex vivo lung perfusion (EVLP) with acellular perfusate.

Background: Ex vivo lung perfusion (EVLP) of donor lungs not otherwise acceptable for transplantation can provide outcomes similar to standard-criteria lung transplantation and has been reported to increase transplant volume by approximately 20% in some transplant centers. Evidence to support decisions about use of EVLP is limited, so expert opinion can be a useful decision aid. This study developed expert consensus recommendations for EVLP with acellular perfusate using a modified Delphi method. Methods: A panel of 18 physicians with expertise in lung transplantation and EVLP who practice in North America completed three surveys on EVLP: Survey 1 used open-ended questions; Survey 2 used primarily Likert-scale questions; and Survey 3 repeated Survey 2 while providing panelists with the Survey 2 results. A follow-up meeting after Survey 3 probed open questions. Results: The primary goal for EVLP is expanding the number of donor lungs available for transplant. Lungs that are acceptable after EVLP are equivalent to lungs that met standard criteria initially. Lungs with unclear or marginal quality should be placed on EVLP for evaluation, including lungs received from third party organizations with incomplete or concerning information. Decisions on whether to put lungs on EVLP require nuanced clinical judgement and should consider compliance and deflation, the ratio of PaO2 to fraction of inspired oxygen (P/F ratio), peak inspiratory pressure (PIP), edema on imaging, and bronchoscopy, with additional parameters considered as appropriate if lung quality is unclear. EVLP lungs are appropriate for transplant if all relevant parameters are acceptable and may be appropriate if some parameters are borderline depending on clinical judgment. Decisions about transplanting EVLP lungs should consider radiography, delta PO2, overall movement, STEEN Solution™ loss, bronchoscopy, peak airway pressure, and palpation, along with other parameters as appropriate. Key open areas for research include evidence-based criteria for lung selection and assessment, the role of biomarkers, and enhanced techniques and perfusion solutions. In addition, the role of EVLP is unclear in lungs with pulmonary emboli and lungs procured with normothermic regional perfusion (NRP), as is the maximal duration of cold ischemia time (CIT). Conclusions: Decisions about EVLP require nuanced consideration of numerous parameters. Expert opinion from this study may help optimize use of EVLP.