Comparison between lung preservation solutions Perfadex and LPD-G with a ex vivo lung perfusion model

INTRODUCTION: Pulmonary preservation techniques aim at improving graft quality and increasing tolerance during reperfusion and cold ischemia times. Currently, the most used technique consists of pulmonary artery anterograde perfusion with Perfadex. The high cost associated with the importation of this solution and the logistical difficulties of our ports and airports regarding medical supplies have caused problems for lung transplant centers in Brazil. Therefore there is need for a preservation solution manufactured in Brazil. The aim of this study is to compare the pulmonary preservation solutions Perfadex and LPD-G manufactured in Brazil in an ex vivo lung perfusion (EVLP) model. METHODS: Donors with brain death, whose lungs had been declined by transplantation teams were used. Cases were randomized into two groups: in Group 1, Perfadex was used for pulmonary preservation. In Group 2, LPDnac, a solution manufactured in Brazil and whose compositon is identical to Perfadex, was used. After harvesting, lungs were stored at 4 °C for 10 hours. An EVLP system was used and the pulmonary block was ventilated and perfused by an acellular solution at 37 °C for 60 minutes. Ischemic-reperfusion injury was measured by functional (blood gas, pulmonary vascular resistance, lung compliance, wet/dry weight ratio) and histological parameters. Pulmonary biopsies were performed at three time points: before harvesting, 10 hours after cold ischemia and 60 minutes after reperfusion. Samples were prepared for light microscopy analysis. Several criteria were used (alveolar edema, interstitial edema, hemorrhage etc.) to create a lung injury score (LIS). Apoptotic cell count was carried out using the TUNEL methodology (TdT-mediated dUTP nick end labeling). RESULTS: After reperfusion, mean oxygenation capacity was 406.0 mmHg in Group 2 and 405.3 mmHg in Group 1 (p = 0.98). Mean pulmonary vascular resistance in Group 2 lungs was 378.3 dina.s.cm-5, whereas in Group 1 it was 697.6 dina.s.cm-5 (p = 0.035). Mean pulmonary compliance by the end of reperfusion was 49.3 ml/cmH2O in Group 2 and 46.8 cmH2O in Group 1 (p = 0.816). Mean wet/dry weight ratio was 2.02 and 2.06 in Groups 2 and 1, respectively (p = 0.87). Mean LIS for the biopsy performed after reperfusion was 4.37 and 4.37 in Groups 2 and 1, respectively (p= 1.0); apoptotic cell count was 137.50/mm2 and 118.75/mm2 in Groups 2 and 1, respectively (p = 0.71). CONCLUSION: The preservation solution manufactured in Brazil proved to be as good as Perfadex. The clinical application for the new solution may reduce costs, favoring the maintenance and opening of pulmonary transplantation centers