Histologic and functional evaluation of lungs reconditioned by ex vivo lung perfusion

Background Only about 15% of donor lungs are considered suitable for transplantation (LTx). Ex vivo lung perfusion (EVLP) has been developed as a method to reassess and repair damaged lungs. We report our experience with EVLP in non-acceptable donor lungs and evaluate its ability to recondition these lungs. Methods We studied lungs from 16 brain-dead donors rejected for LTx. After harvesting, the lungs were stored at 4°C for 10 hours and subjected to normothermic EVLP with Steen Solution (Vitrolife, Goteborg, Sweden) for 60 minutes. For functional evaluation, the following variables were assessed: partial pressure of arterial oxygen (Pao 2 ), pulmonary vascular resistance (PVR), and lung compliance (LC). For histologic assessment, lung biopsy was done before harvest and after EVLP. Tissue samples were examined under light microscopy. To detect and quantify apoptosis, terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling assay was used. Results Thirteen lung donors were refused for having impaired lung function. The mean Pao 2 obtained in the organ donor at the referring hospital was 193.7 mm Hg and rose to 489 mm Hg after EVLP. During EVLP, the mean PVR was 652.5 dynes/sec/cm 5 and the mean LC was 48 ml/cm H 2 O. There was no significant difference between the mean Lung Injury Score before harvest and after EVLP. There was a trend toward a reduction in the median number of apoptotic cells after EVLP. Conclusions EVLP improved lung function (oxygenation capacity) of organs considered unsuitable for transplantation. Lung tissue structure did not deteriorate even after 1 hour of normothermic perfusion.