Evaluation of the HeartWare HVAD centrifugal pump for right ventricular assistance in an in vitro model.

We have developed a method that allows the use of a commercially available implantable left ventricular assist device (LVAD; HeartWare HVAD) for right ventricular (RV) assistance. A mock circulation was used to examine the flow characteristics of the system with different outflow diameters (10-4 mm). Furthermore, we looked for a material for safe and satisfactory reduction of the effective length of the inflow cannula for better fitting to the RV dimensions. Reduction of the outflow graft to an inner diameter of ∼5 mm adds as much resistance to the system that in patients with a normal pulmonary resistance, the pump would deliver between 3.5 and 7 L/min. We added two 5 mm silicon suture rings to the system's "apical" sewing ring to reduce the effective length of the inflow cannula. Connection of the pump to the anterior free wall of the right ventricle ensures good orientation of the inflow cannula within the RV cavity, with sufficient space to prevent the inflow cannula from suction to the opposite interventricular septum. The HeartWare LVAD pump seems also to be usable as a right ventricular assist device (RVAD) after a few, but important, modifications of the implant procedure.