Haemodynamic evaluation of the new pulsatile-flow generation method in vitro

Abstract

Continuous-flow ventricular-assist devices are widely used to support patients with advanced heart failure, because continuous-flow ventricular-assist devices are more durable, have smaller sizes and have better survival rates for patients compared to the pulsatile-flow ventricular-assist devices. Nevertheless, continuous-flow ventricular-assist devices often cause complications such as gastrointestinal bleeding, haemorrhagic stroke, and aortic insufficiency and have a negative impact on the microcirculation for both long-time implantable and short-time extracorporeal systems. The aim of this study is the evaluation of the pulsatile-flow generation method in continuous-flow ventricular-assist device without pump speed changes. The method may be used for short-time extracorporeal continuous-flow mechanical circulatory support and long-time implantable mechanical circulatory support. A shunt with a controlled adjustable valve, that clamps periodically, is connected in parallel to the continuous-flow ventricular-assist device. We compared the continuous-flow ventricular-assist device operating with and without the shunt on the mock circulation loop. The continuous-flow ventricular-assist device–shunt system was connected according to the left ventricle–aorta circuit and worked in phase with the ventricle. Heart failure was simulated on the mock circulation circuit. Rotaflow (Maquet Inc.) was used as the continuous-flow pump. Haemolysis studies of the system for generating a pulse flow were carried out at a flow rate of 5 L/min and a pressure drop of 100 mm Hg. To compare the haemodynamic efficiency, we used the aortic pulsation index Ip, the equivalent energy pressure and the surplus haemodynamic energy. These indexes were higher in the pulsatile mode ( Ip – 4 times, equivalent energy pressure by 7.36% and surplus haemodynamic energy – 10 times), while haemolysis was the same. The normalised index of haemolysis was 0.0015 ± 0.001. The results demonstrate the efficiency of the pulsatile-flow generation method for continuous-flow ventricular-assist devices without impeller rotation rate changes.

Unveiling the future of cardiac care: advances in mechanical circulatory support

“…This prompted the development of secondand third-generation VADs, such as continuous-flow devices, which offered improvements in size, biocompatibility, durability, and effectiveness [28]. The transition to continuous-flow devices was further supported by the recognition of their enhanced durability, smaller sizes, and better survival rates compared to pulsatile-flow devices [29].…”

Hemodynamic evaluation of pulsatile-flow generating device in left ventricular assist devices

“…Ранее для повышения уровня пульсации в ННП нами был предложен метод с использованием параллельного подключения к насосу (вход-выход) канала рециркуляции [16][17]. При этом работа системы обеспечивалась установленным в канале рециркуляции управляемым электромеханическим клапаном, который требовал относительно большой мощности для перекрытия канала рециркуляции в систолической фазе [18].…”