Retrograde Flush Following Warm Ischemia in the Non-Heart-Beating Donor Results in Superior Graft Performance at Reperfusion

BackgroundThe use of non-heart-beating donors (NHBD) has been propagated as an alternative to overcome the scarcity of pulmonary grafts. The presence of postmortem thrombi, however, is a concern for the development of primary graft dysfunction. In this isolated lung reperfusion study, we looked at the need and the best route of preharvest pulmonary flush.MethodsDomestic pigs were sacrificed by ventricular fibrillation and divided in 3 groups (n = 6 per group). After 1 h of in situ warm ischemia, lungs in group I were retrieved unflushed (NF). In group II, lungs were explanted after an anterograde flush (AF) through the pulmonary artery. Finally, in group III, lungs were explanted after a retrograde flush (RF) via the left atrium. After 3 h of cold storage, the left lung was assessed for 60 min in our ex vivo reperfusion model. Wet-to-dry weight ratio (W/D) was calculated after reperfusion.ResultsPulmonary vascular resistance (dynes × sec × cm−5) was 1145 ± 56 (RF) versus 1560 ± 123 (AF) and 1435 ± 95 (NF) at 60 min of reperfusion (P < 0.05). Oxygenation and compliance were higher and plateau airway pressure was lower in RF versus AF and NF, although the difference did not reach statistical significance. No differences in W/D were observed between groups after reperfusion. Histological examination revealed fewer microthrombi in the left lung in RF compared with AF and NF.ConclusionRF of lungs from NHBD improves graft function by elimination of microthrombi from the pulmonary vasculature, resulting in lower pulmonary vascular resistance upon reperfusion.