Hemodynamics with Mechanical Circulatory Support Devices Using a Cardiogenic Shock Model

Abstract

AbstractBackgroundMechanical circulatory support (MCS) devices, including veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and Impella, have been widely used for patients with cardiogenic shock (CS). However, hemodynamics with each device and combination therapy is not thoroughly understood. We aimed to elucidate the hemodynamics with MCS using a CS pulsatile flow model.Methods and ResultsA pulsatile flow circulation system comprising a ventricle, aortic valve, mitral valve, elastic artery, and venous reservoir was developed. Hemodynamics with Impella CP, VA-ECMO, and a combination of Impella CP and VA-ECMO were assessed based on the pressure and flow under support with each device and the pressure-volume loop of the ventricle model. The self-recirculation with Impella was assessed using particle image velocimetry. The Impella CP device with CS status resulted in increased afterload, leading to an increase in aortic pressure and a decrease in end-diastolic volume and end-diastolic pressure (EDP). VA-ECMO support resulted in increased afterload, leading to a significant increase in aortic pressure with an increase in end-systolic volume and EDP and decreasing venous reservoir pressure. The combination of Impella CP and VA-ECMO led to left ventricular unloading, regardless of increase in afterload. Self-recirculation with Impella CP was observed in a patient with significant aortic insufficiency, leading to reduced hemodynamic support.ConclusionsThe Impella system improved hemodynamics with ventricular unloading. Hemodynamic support with Impella and VA-ECMO should be a promising combination for patients with severe CS. Physicians should be alert to the presence of significant aortic insufficiency, leading to self-recirculation with Impella.Clinical PerspectiveWhat is new?This is a non-clinical study using a novel experimental pulsatile flow system with venous function that can be used to assess MCS, including Impella and VA-ECMO.The self-recirculation phenomenon of the Impella device was assessed by a flow visualization method using particle imaging velocimetry.What are the clinical implications?The combination of Impella and VA-ECMO led to left ventricular unloading, regardless of the increase in afterload.VA-ECMO could increase arterial pressure owing to increased LV afterload and alter the direction of the aortic flow (antegrade or retrograde) depending on the flow level with VA-ECMO.Effective Impella flow was reduced during ventricular diastole when aortic insufficiency was present owing to self-recirculation with the Impella device.