RESUMEN
A new accessory was developed to allow implantation of left ventricular assist devices (LVADs) without requiring an anastomosis to the ascending aorta. The accessory combines the LVAD inflow and outflow into a dual-lumen device. Initial prototypes encountered reduced pump performance in vitro, but a second-generation prototype successfully addressed this issue. This feasibility study aimed to demonstrate the anatomic fit, safe implantation, and hemodynamic effectiveness of the LVAD with the accessory. The accessory was implanted in ten female pigs (104 ± 13 kg). Following sternotomy and apical coring under cardiopulmonary bypass, a balloon catheter was retrogradely inserted and exteriorized through the coring site, where it was inflated within the distal third of the outflow graft. It was utilized to pull the accessory's outflow across the aortic valve. After LVAD attachment, the catheter was removed. Echocardiography revealed no relevant valve regurgitation post-implantation. During ramp testing, pump flow increased from 3.7 ± 1.2 to 5.4 ± 1.2 L/min. Necropsy confirmed correct accessory placement in nine animals. No valve lesions or device thrombosis were observed. The accessory enabled LVAD implantation without compromising pump performance. Future work includes design refinements for implantation without cardiopulmonary bypass and long-term testing in a chronic heart failure model.
RESUMEN
A novel accessory directing the blood from the outflow of a left ventricular assist device (LVAD) back through the left ventricular apex and across the aortic valve allows LVAD implantation via the left ventricular apex solely but may affect the LVAD performance. We quantified the effect of the accessory on LVAD flow and pressure head in vitro. In a mock circulatory loop, a centrifugal-flow LVAD (HeartMate 3, Abbott, Abbott Park, IL, USA) with (Accessory) and without the accessory (Control) was compared under physiological conditions using a water/glycerol solution as a blood substitute. The pump was operated at 4000, 5200, and 6400 rpm and 5 different resistance levels. Flow, inlet, and outlet pressure were measured, and pressure head was calculated. Compared to the Control, flow and pressure head in the Accessory group were reduced by an overall average of 0.26 L/min and 9.9 mmHg (all speeds and resistance levels). The highest decline in flow and pressure head occurred at the lowest resistance levels. In conclusion, the accessory leads to a reduction of LVAD flow and pressure head that is enhanced by decreases in resistance. Future developments in the LVAD accessory's design may reduce these effects and allow unimpaired LVAD performance and minimally invasive device implantation.
