Experimental Investigation Of The Effect Of Compliance Properties On The Flow In An Analogous Ex-Vivo Heart Perfusion System

Abstract

—The heart transplant waiting list far exceeds supply. This shortage is generally attributed to the high number of discarded hearts and to the narrow six-hour time window currently available through the standard preservation method: static cold storage (SCS). An alternative method called ex-vivo heart perfusion (EVHP) maintains a human donor heart beating outside the body for the time preceding transplantation surgery. By keeping the heart working in a physiologically consistent way and monitoring its functions, the organ’s health can be assessed and the transplant time window can be extended. In order to improve and optimize the EVHP system, the present work aims to further investigate the relationship between pulsatile flow and compliance by assessing the effect of different compliant tubes on the upstream and downstream pressure and flow fields. Hence, silicone tubes of variable compliance, length, and geometrical shape were developed for this study — although only one sample has been tested so far, in addition to an experimental setup containing a hydraulic circuit analogous to the left flow loop of the EVHP system. The flow fields downstream of the compliant section are assessed using laser Doppler velocimetry (LDV). Findings will include novel visualizations of these flow fields as well as comparisons of pressure waveforms from an assortment of compliance conditions .