Development of a next-generation Mock Circulatory Loop (MCL)

With 31.5% of deaths worldwide, cardiovascular diseases are the number one cause of death globally. Due to the limited availability of suitable donor organs, the need for developing alternative cardiac assist devices (CAD) such as total artificial hearts (TAH) and ventricular assist devices (VAD), has increased.
The performance of CAD is primarily evaluated in-vitro by mechanical-electrical-hydraulic systems that mimic the function of the natural circulatory system, often called a mock circulatory loop (MCL). Generally, the system structure of the MCL consists of three parts: a resistance and compliance module connected to a pump. MCLs adopt pulsatile flow in combination with artificial heart valves to simulate the physiological blood flow. Valves and compliance chambers resemble physiological impedance and mimic physiological or pathological conditions in terms of pressure and flow.
Early and still current MCLs focus on reproducing hemodynamic parameters like flow, pressure, waveforms, resistance and compliance, while mimicking and visualizing wave phenomena seemed to be only of minor concern. MCLs with accurate silicon anatomical structures would be able to asses clinically relevant flow phenomena.
Numerical models of the arterial system are developed in parallel to the MCL. However, they neglect and simplify most physiological aspects and complex properties of the cardiovascular system. These numerical circulatory models are merged with hydraulic models to improve flexibility and accuracy, obtaining a hybrid mock circulatory loop (HMCL). In an HMCL the numerical and hydraulic parts run in parallel, the response data in each is communicated to the other real-time through a numerichydraulic interface. The HMCL can describe cardiovascular characteristics using computer algorithms that are too difficult to represent with hydraulic components.
This project will propose a next-generation HMCL, which includes a model of the 55 largest branches of the arterial tree. The HMCL will be fully automated in order to implement the Frank-Starling mechanism and autoregulatory system. Earlier HMCL were already successful in providing a reasonable simulation of some physiological phenomenon, however, with the proposed improvements it will be possible to study a greater number of physiological problems with more sophisticated tools that will replicate the behaviour of the in-vivo response much more closely.
Aim 1: Development of a mechanical physiologically representative MCL
Development of a physiologically correct-dimension artificial aorta with 55 branches. The arterial model with 55 branches will provide superb arterial waveforms with almost identical results to those observed in vivo. Furthermore, development of an artificial left ventricle with flexible walls will allow the investigation of the Frank-Starling mechanism.
Aim 2: Development of the computational and autonomic models
Segments that are not represented by the physical arterial model are constructed in a computational model. The computational model will be based on 1D formulations, which introduces time as a parameter allowing the study of wave travel and reflection. Furthermore, development of an autonomic model that will simulate the effect of the baroreceptors in the aorta and carotid arteries in response to changes of pressure.
Aim 3: Test and evaluate the HMCL
Connecting the computational and autonomic model through an electrical-hydraulic interface. Additionally, the control system needs to work together with the HMCL to simulate baroreceptor response. Furthermore, evaluate the performance of the HMCL with existing CAD.