Hemodynamic effects of pumpless extracorporeal membrane oxygenation (ECMO) support for chronically pressure-overloaded right heart failure in a canine experimental model.

PURPOSE: This study was done to evaluate the hemodynamic effects of a pumpless implantable extracorporeal membrane oxygenation (ECMO) circuit between the right ventricle (RV) and left atrium (LA) in a chronic canine model with an RV pressure overload.

METHOD: We created a model of right-sided heart failure by pulmonary artery banding in ten dogs for a duration of more than 3 months. After demonstrating that the RV pressure increased, a bypass circuit was created between the RV and LA with an in-line oxygenator. Both the hemodynamics and gas exchange were measured.

RESULTS: The effects of a pulmonary bypass in nine dogs were studied. Approximately half of the RV output was passively shunted through the bypass circuit, and a marked reduction in the RV pressure and recovery from right heart failure were observed. After a complete ligation of the main pulmonary artery, five of the nine dogs survived more than 6 h. The RV pressure did not change significantly, but the cardiac output and blood pressure gradually decreased. The blood gas state was sufficiently maintained throughout the experiment.

CONCLUSION: The present study indicates the hemodynamic benefit of a partial pumpless ECMO system in dogs with chronically pressure-overloaded right heart failure; however, the experimental preparation of the total pumpless ECMO circuit proved to be unstable.