Characterization of an Adult Mock Circulation for Testing Cardiac Support Devices

Abstract

A need exists for a mock circulation that behaves in a physiologic manner for testing cardiac devices in normal and pathologic states. To address this need, an integrated mock cardiovascular system consisting of an atrium, ventricle, and systemic and coronary vasculature was developed specifically for testing ventricular assist devices (VADs). This test configuration enables atrial or ventricular apex inflow and aortic outflow cannulation connections. The objective of this study was to assess the ability of the mock ventricle to mimic the Frank-Starling response of normal, heart failure, and cardiac recovery conditions. The pressure-volume relationship of the mock ventricle was evaluated by varying ventricular volume over a wide range via atrial (preload) and aortic (afterload) occlusions. The input impedance of the mock vasculature was calculated using aortic pressure and flow measurements and also was used to estimate resistance, compliance, and inertial mechanical properties of the circulatory system. Results demonstrated that the mock ventricle pressure-volume loops and the end diastolic and end systolic pressure-volume relationships are representative of the Starling characteristics of the natural heart for each of the test conditions. The mock vasculature can be configured to mimic the input impedance and mechanical properties of native vasculature in the normal state. Although mock circulation testing systems cannot replace in vivo models, this configuration should be well suited for developing experimental protocols, testing device feedback control algorithms, investigating flow profiles, and training surgical staff on the operational procedures of cardiovascular devices.

In Vitro Evaluation of an Axial Flow Pump: Mock-Pump Interaction and an Approach to Control

“…Cardiovascular physical models include distributed parameters or lumped element designs, for both systemic and total circulation, depending on the application (5,6,12,24,25).…”

“…There is a pressure transient observed in the aortic pressure waveform during the aortic valve closure (Fig. 4) that could be linked to the rigid mounting of the mechanical valve and mock vasculature inertial effects (6). In some experiments, this mechanical artifact produced small fluctuations in the IP Ao value; consequently, before calculating the IP Ao , the aortic pressure signal was truncated (another possible solution was to use low-pass filtering of the aortic pressure signal).…”

“…Cardiovascular mock systems are a useful tool during the development of a cardiac assist device (5)(6)(7)(8). Safety and reliability trials required by the FDA for market approval include in vitro failure analysis utilizing a mock circulatory loop (5).…”

A Preload and Afterload Sensitive Artificial Ventricle to Test Cardiovascular Prostheses

“…Hydraulic mock circulatory systems (MCSs) are widely used to test mechanical cardiac assist devices (CADs) (Baloa et al, 2001), (Pantalos et al, 2004), (Shi et al, 2004) and (Matthew and Yih-Choung, 2004). They are an important tool for CADs' design and testing.…”

Treatment of severe aortic stenosis : experimental design, testing, and analysis of an aortic valve bypass apical cannula.

“…The software used to for data acquisition is also a custom built LabVIEW (National Instruments, Austin, TX) described by Drew et al (31,32). This graphical Pantalos et al (7). Due to its versatility and robustness, the mock loop is able to test the AVB system providing a powerful in vitro testing environment.…”