Innovative pulmonary preservation of non-heart-beating donor grafts in experimental lung transplantation

Abstract

Objective: Lung transplantation is limited by scarcity of donor organs. Lung retrieval from non-heart-beating donors (NHBD) might have the potential to extend the donor pool and has been reported recently. However, no studies in NHBD exist using the novel approach of retrograde preservation with Perfadex solution.

Methods: Asystolic heparinized pigs (n = 5/group) were continuously ventilated for 90, 180 or 300 min of warm ischemia. Lungs were then retrogradely preserved with Perfadex and stored at 4 degrees C in inflation. After 3 h of additional cold ischemia, left lung transplantation was performed. Hemodynamics, pO(2)/F(i)O(2) and dynamic compliance were monitored for 5 h. Intrapulmonary lung water was determined by both global wet-to-dry lung weight ratio (W/D ratio) and standard stereological examination of relative volume fractions of intraalveolar edema. All results were compared to sham-operated controls and to lungs obtained from standard heart-beating donors after retrograde preservation with Perfadex and 27 h of cold ischemia. Statistics comprised ANOVA analysis with repeated measures and Mann-Whitney tests.

Results: No mortality was observed. During flush preservation of NHBD lungs, continuous elimination of blood clots via the pulmonary artery was observed. Oxygenation, compliance, intraalveolar edema fraction and W/D ratio were comparable between groups, whereas PVR was significantly lower in sham-controls.

Conclusions: Use of NHBD lungs is feasible and results in similar postischemic outcome when compared to sham-controls and standard preservation procedures even after 5 h of pre-harvest warm ischemia. Especially, the NHBD with high-risk constellations for intravascular coagulation might benefit from retrograde preservation by elimination of thrombi from the pulmonary circulation. This innovative technique might also be considered in situations, where brain-dead organ donors become hemodynamically unstable prior to onset of organ harvest. Further trials with longer warm and cold ischemic periods are initiated to further elucidate this promising approach of donor pool expansion.