Protective Role of ECMO on Reperfusion Injury and Acute Rejection in Lung Transplantation: A Pathological Analysis

Abstract

Purpose The routine utilization of intraoperative extracorporeal membrane oxygenation (ECMO) in lung transplantation is recently extensively investigated for its protective role, especially on reperfusion injury. The purpose of this study is to compare pathological features on pre and post-reperfusion biopsies and on 30 and 90-days surveillance trans-bronchial biopsies in lung transplantations performed with or without ECMO support to assess its protective role on the graft Methods 51 patients (13 with ECMO support, 38 without ECMO support) underwent bilateral lung transplantation at our Institution between 2012 and 2019. Only patients on ECMO at time of anesthetic induction or before the first clamping of the pulmonary artery were included. Patients submitted to graft volume reduction before lung reperfusion were excluded from the analysis.Intra-operative pre and post-reperfusion biopsies were collected to analyze edema, leucocyte margination and congestion/extravasation (score 0-3). The presence of acute rejection (grade A0-3, grade B0-2) diffuse alveolar damage (DAD), organizing pneumonia (OP) on 30 and 90-days trans-bronchial surveillance biopsies was also compared in the two groups. Results No significant differences were found between the two groups in terms of edema, leucocyte margination and congestion in pre reperfusion biopsies. On post reperfusion biopsies, leucocyte margination was significantly less frequent in ECMO group (46% vs 76%; p=0.043). A lower frequency of acute rejection (grade A0-3) was also found in the ECMO group on 30-days biopsies (25% vs 58%, p=0.047). Conclusion In conclusion, this analysis does not show significant differences between the two groups except for a lower frequency of leucocyte margination at post-reperfusion biopsies and acute rejection at 30-days biopsies in the ECMO group. Other studies, with a larger population, are needed in order to evaluate whether the positive clinical impact of using ECMO as a prevention of reperfusion edema after lung transplantation can also be explained by a defined pathological picture