Recovery From Exhaustion of the Frank-Starling Mechanism by Mechanical Unloading With a Continuous-Flow Ventricular Assist Device

摘要

Background: We describe our original left ventricular assist device (LVAD) speed ramp and volume loading test designed to evaluate native heart function under continuous-flow LVAD support. Methods?and?Results: LVAD speed was decreased in 4 stages from the patient’s optimal speed to the minimum setting for each device. Under minimal LVAD support, patients were subjected to saline loading (body weight [kg]×10 mL in 15 min). Echocardiographic and hemodynamic data were obtained at each stage of the LVAD speed ramp and every 3 min during saline loading. Patients were divided into Recovery (with successful LVAD removal; n=8) and Non-recovery (others; n=31) groups. During testing, increased pulmonary capillary wedge pressure caused by volume loading was milder in the Recovery than Non-recovery group (repeated measures analysis of variance; group effect, P=0.0069; time effect, P0.0001; interaction effect, P=0.0173). Increased cardiac output from volume loading was significantly higher in the Recovery than Non-recovery group (group effect, P=0.0124; time effect, P0.0001; interaction effect, P=0.0091). Therefore, the Frank-Starling curve of the Recovery group was located upward and to the left of that of the Non-recovery group. Conclusions: The LVAD speed ramp and volume loading test facilitates the precise evaluation of native heart function during continuous-flow LVAD support.