Potential Application of the CircuLite® Synergy® Circulatory Support System in the Treatment of Pulmonary Arterial Hypertension

Purpose The high mortality rate of pulmonary arterial hypertension (PAH) mainly relates to progressive right ventricular (RV) failure. With limited efficacy of medical therapies, mechanical circulatory support for the RV has been considered. However, there is lack of understanding of the hemodynamic effects of mechanical support in this setting. Methods and Materials We modeled the cardiovascular system, simulated cases of PAH and RV dysfunction and assessed the theoretical effects of the CircuLite ® Synergy ® continuous flow micro-pump as an Right Heart assist device with flow rates between 2-4.25L/minute. Inflow was sourced either from the RV or RA and outflow was to the pulmonary artery. Synergy support was set at various flow rates and additional simulations were carried out in the presence of atrial septostomy (ASD) and tricuspid regurgitation (TR). Results In the simulation, Synergy support increased LV filling, thus improving cardiac output and arterial pressure, unloading the RA and RV, while raising pulmonary arterial and capillary pressures in an flow-dependent manner. These effects diminished with increasing disease severity. The presence of TR did not significantly impact the hemodynamic effects of Synergy support. ASD reduced the efficacy of Synergy support, since right-to-left shunting decreased and ultimately reversed with increasing Synergy support due to the progressive drop in RA pressure. Conclusions The results of this theoretical analysis suggest that Synergy support can effectively increase cardiac output and decreases RA pressure with the consequence of increasing pulmonary artery and capillary pressures. Especially in advanced PAH, low Synergy flow rates may mitigate these potentially detrimental effects while effectively increasing systemic hemodynamics. Six chronic (60-day) animals studies are scheduled to evaluate the performance of the Synergy device with the inflow cannula implanted in the RA and outflow to the pulmonary artery.