Evaluating acellular versus cellular perfusate composition during prolonged ex vivo lung perfusion after initial cold ischaemia for 24 hours.

Normothermic ex vivo lung perfusion (EVLP) has developed as a powerful technique to evaluate particularly marginal donor lungs prior to transplantation. In this study, acellular and cellular perfusate compositions were compared in an identical experimental setting as no consensus has been reached on a preferred technique yet. Porcine lungs underwent EVLP for 12 h on the basis of an acellular or a cellular perfusate composition after 24 h of cold ischaemia as defined organ stress. During perfusion, haemodynamic and respiratory parameters were monitored. After EVLP, the lung condition was assessed by light and transmission electron microscopy. Aerodynamic parameters did not show significant differences between groups and remained within the in vivo range during EVLP. Mean oxygenation indices were 491 ± 39 in the acellular group and 513 ± 53 in the cellular group. Groups only differed significantly in terms of higher pulmonary artery pressure and vascular resistance in the cellular group. Lung histology and ultrastructure were largely well preserved after prolonged EVLP and showed only minor structural alterations which were similarly present in both groups. Prolonged acellular and cellular EVLP for 12 h are both feasible with lungs prechallenged by ischaemic organ stress. Physiological and ultrastructural analysis showed no superiority of either acellular or cellular perfusate composition.