A mock heart engineered with helical aramid fibers for in vitro cardiovascular device testing

Abstract

Mock heart circulation loops (MHCLs) serve as in-vitro platforms to investigate the physiological interaction between circulatory systems and cardiovascular devices. A mock heart (MH) engineered with silicone walls and helical aramid fibers, to mimic the complex contraction of a natural heart, has been developed to advance the MHCL previously developed in our group. A mock aorta with an anatomical shape enables the evaluation of a cannulation method for ventricular assist devices (VADs) and investigation of the usage of clinical measurement systems like pressure-volume catheters. Ventricle and aorta molds were produced based on MRI data and cast with silicone. Aramid fibers were layered in the silicone ventricle to reproduce ventricle torsion. A rotating hollow shaft was connected to the apex enabling the rotation of the MH and the connection of a VAD. Silicone wall thickness, aramid fiber angle and fiber pitch were varied to generate different MH models. All MH models were placed in a tank filled with variable amounts of water and air simulating the compliance. In this work, physiological ventricular torsion angles (15°-26°) and physiological pressure-volume loops were achieved. This MHCL can serve as a comprehensive testing platform for cardiovascular devices, such as artificial heart valves and cannulation of VADs.

Bioinspired Construction of Artificial Cardiac Muscles Based on Liquid Crystal Elastomer Fibers

“…Figure 3e demonstrated the ejection fraction (EF) referring to the percentage of fluid pumped per beat. [39] It turned out that the EF of C+H cardiac muscle reached 22.4%, much higher than 7.6% for only-C and 10.6% for only-H designs. The work density of LCE fibers calculated from EF results was shown in Figure 3f, it also indicated that among all three designs, C+H cardiac muscle possessed the highest working density of 4.1 kJ m −3 , comparing to 1.3 and 1.4 kJ m −3 in only-C and only-H cardiac muscles, respectively.…”

Use of 3D anatomical models in mock circulatory loops for cardiac medical device testing

“…11,25,36,38,45,54,63,64,[67][68][69][70]73 In these cases, ventricular blood flow was simulated either as a generic sinusoidal waveform or using pulsatile pumps that could change the stroke volume, heart rate and systolediastole ratio. More sophisticated MCLs considered either part 12,[16][17][18][19]22,23,[30][31][32][33][34][35]46,48,52,60,61,65,66,74 or all the cardiovascular system 13,14,29,39,40,49,50,53,75 by including compliance chambers and variable resistances or, in few cases, by simulating it computationally.…”

“…A mold of the anatomy enables painting the surface layer-by-layer or to opt for the dip molding process repeated until the desired thickness is obtained. 22,23 Alternatively, both an external and an internal mold are 3D printed and a liquid solution is poured into them. 15 The materials used for this technique are silicone and polyvinyl alcohol cryogel (PVA-c).…”

“…22,36 T A B L E 2 Applications of a MCL combined with a 3D anatomical site to test implantable blood pumpApplications of aIntracardiac pumps are miniaturized VADs placed in transvalvular position, draining blood from the ventricular cavity and ejecting it into the aorta. An example is the intraventricular balloon pump, consisting of a flexible balloon that inflates and deflates inside the left ventricle.…”

A left ventricular phantom for 3D echocardiographic twist measurements

“…A phantom was designed to mimic a contracting and twisting left ventricle (Figure 1), using a similar technique as has been recently published for other cardiac simulation studies [21]. This phantom was entirely made from PVA with wall properties to introduce twist, thereby avoiding any apical deformation attachment.…”