Extracorporeal Circulation During Lung Transplantation Procedures: A Meta-Analysis.

Extracorporeal circulation (ECC) is an invaluable tool in lung transplantation (lutx). More than the past years, an increasing number of centers changed their standard for intraoperative ECC from cardiopulmonary bypass (CPB) to extracorporeal membrane oxygenation (ECMO) - with differing results. This meta-analysis reviews the existing evidence. An online literature research on Medline, Embase, and PubMed has been performed. Two persons independently judged the papers using the ACROBAT-NRSI tool of the Cochrane collaboration. Meta-analyses and meta-regressions were used to determine whether veno-arterial ECMO (VA-ECMO) resulted in better outcomes compared with CPB. Six papers - all observational studies without randomization - were included in the analysis. All were considered to have serious bias caused by heparinization as co-intervention. Forest plots showed a beneficial trend of ECMO regarding blood transfusions (packed red blood cells (RBCs) with an average mean difference of -0.46 units [95% CI = -3.72, 2.80], fresh-frozen plasma with an average mean difference of -0.65 units [95% CI = -1.56, 0.25], platelets with an average mean difference of -1.72 units [95% CI = -3.67, 0.23]). Duration of ventilator support with an average mean difference of -2.86 days [95% CI = -11.43, 5.71] and intensive care unit (ICU) length of stay with an average mean difference of -4.79 days [95% CI = -8.17, -1.41] were shorter in ECMO patients. Extracorporeal membrane oxygenation treatment tended to be superior regarding 3 month mortality (odds ratio = 0.46, 95% CI = 0.21-1.02) and 1 year mortality (odds ratio = 0.65, 95% CI = 0.37-1.13). However, only the ICU length of stay reached statistical significance. Meta-regression analyses showed that heterogeneity across studies (sex, year of ECMO implementation, and underlying disease) influenced differences. These data indicate a benefit of the intraoperative use of ECMO as compared with CPB during lung transplant procedures regarding short-term outcome (ICU stay). There was no statistically significant effect regarding blood transfusion needs or long-term outcome. The superiority of ECMO in lutx patients remains to be determined in larger multi-center randomized trials.