Moderate Flow is Superior to Low Flow Perfusion in a Juvenile Porcine Transplantation Model of Ex-Situ Lung Perfusion

Abstract

<h3>Purpose</h3> Ex-situ lung perfusion (ESLP) extends preservation time, while reconditioning donor lungs of marginal quality to expand the donor pool. Full cardiac output (CO) flow results in unacceptable levels of edema formation during ESLP. The ideal flow rate has not been studied systematically. We report our results of moderate flow (30% CO) vs low flow (10% CO) 12-hour normothermic negative pressure ventilation (NPV) ESLP with transplantation in a juvenile porcine model. <h3>Methods</h3> Twelve pig lungs underwent 12-hours of NPV-ESLP at 38 Celsius with 30% CO (n=6) or 10% CO (n=6) perfusion. Three left lungs from each group were transplanted post ESLP and assessed in-vivo over four-hours. Donor lung function was assessed using physiologic parameters, edema formation, cytokine profiles, and histopathologic analysis. <h3>Results</h3> Moderate- and low-flow lungs demonstrated stable and acceptable oxygenation during 12-hours of NPV-ESLP; however, after transplantation low-flow lungs demonstrated a significantly worse decline in oxygenation compared to moderate flow lungs. While on ESLP, moderate and low flow lungs demonstrated an improvement in compliance, with relatively stable pulmonary artery pressures and pulmonary vascular resistance. Edema formation post-ESLP was similar between the control and experimental groups; however, isolated left lung edema formation post transplant was significantly worse in the low-flow group. Cytokine and histopathologic analysis are ongoing. <h3>Conclusion</h3> Moderate flow perfusion of porcine lungs results in superior graft function compared to low-flow perfusion over 12-hours of NPV-ESLP and during acute in-vivo transplantation assessment.