Reducing regional flow stasis and improving intraventricular hemodynamics with a tipless inflow cannula design: An in vitro flow visualization study using the EVAHEART LVAD.

Due to the high stroke rate of left ventricular assist device (LVAD) patients, reduction of thrombus has emerged as an important target for LVAD support. Left ventricular blood flow patterns with areas of flow stasis and recirculation are associated with platelet aggregation, which is worsened by exposure to high shear stress. Previous reports of intraventricular thrombus in LVAD patients have identified the outside of the LVAD inflow cannula as a nidus for LV thrombus formation.

Virtual Fitting and Hemodynamic Simulation of the EVAHEART 2 Left Ventricular Assist Device and Double-Cuff Tipless Inflow Cannula.

Inflow malposition during surgery, postoperative pump migration, inflow obstruction, and right ventricular compression are major contributors to low flow and adverse events in patients with ventricular assist devices (VADs). These position abnormalities can lead to adverse events including ischemic stroke. To address these problems, we conducted a virtual anatomical fitting study and hemodynamic simulation on iterative cannula designs, resulting in the EVAHEART 2 with the novel double-cuff tipless (DCT) inflow cannula and smaller pump design.

Preclinical Evaluation of the EVAHEART 2 Centrifugal Left Ventricular Assist Device in Bovines.

The EVAHEART 1 left ventricular assist device was miniaturized to the EVAHEART 2, with a new inflow cannula designed to mitigate the risks of malposition. To evaluate the safety of the new double-cuff tipless inflow cannula, in vivo studies were performed in healthy bovines. Eight consecutive studies were done: five short-term studies of hematological adaptation and three long-term studies of tissue adaptation.

The Effect of Inflow Cannula Length on the Intraventricular Flow Field: An In Vitro Flow Visualization Study Using the Evaheart Left Ventricular Assist Device.

Left ventricular assist device (LVAD) inflow cannula malposition is a significant risk for pump thrombosis. Thrombus development is influenced by altered flow dynamics, such as stasis or high shear that promote coagulation. The goal of this study was to measure the intraventricular flow field surrounding the apical inflow cannula of the Evaheart centrifugal LVAD, and assess flow stasis, vortex structures, and pulsatility for a range of cannula insertion depths and support conditions.

Optimization of axial-pump pressure sensitivity for a continuous-flow total artificial heart.

Background: In this study, we describe the potential advantages of a continuous-flow total artificial heart (CFTAH) comprising two small, non-pulsatile pumps with optimized responsiveness to the pressure gradient.

Methods: We modified a MicroMed DeBakey axial-flow pump by increasing its inducer-impeller inlet angle, thereby increasing its pressure responsivity. We obtained the in vitro pressure gradient response and compared it with those of the clinically used, unmodified MicroMed DeBakey pump, Jarvik 2000 FlowMaker and HeartMate II.