Design and evaluation of a hybrid mock circulatory loop for total artificial heart testing

Aims: A hybrid mock circulatory loop (MCL) was developed for total artificial heart (TAH) performance evaluation. The hybrid MCL consists of hydraulic hardware components and a software computer model. Design: The hydraulic components are divided into the systemic and pulmonary circulation, each of which includes electrically controlled compliances, resistors, and a venous volume which can be adjusted for a wide range of physiological and pathological conditions. The software model simulates the baroreflex autoregulatory response by automatically adjusting the hydraulic parameters according to changes of condition in the MCL. Results: The experimental results demonstrated a good representation of the human cardiovascular system and the capability of real-time variation of physiological and pathological conditions. The functionality of the baroreflex autoregulatory mechanism was evaluated by simulation of a postural change. Conclusions: The hybrid MCL that we developed allows variable and continuous in vitro evaluation of mechanical circulatory support devices in TAH configuration and particularly their control algorithms in response to various cardiovascular conditions. The system has been built in a modular configuration to allow testing of different types of devices and thus provides a valuable test platform prior to animal experiments.