Ex situ heart perfusion (ESHP) is an emerging technique that aims to combat the shortage of organs suitable for transplantation through the augmentation of both donor heart preservation and evaluation. The oldest and most common modality for ESHP is Langendorff mode (LM), where oxygenated perfusate is provided retrograde to the aorta. While this technique is used clinically to extend donor heart preservation time, contractile evaluation of hearts is precluded. This evaluation has been made possible during ESHP, however, by recent research focused on the instillation of different working modes:​ Pump Supported Working mode (PSWM), where afterload is instilled by a pump providing retrograde support to the aortic root, and Passive Afterload Working Mode (PAWM), where passive Windkessel elements are used to instill physiological afterload.

In this thesis, the comparative effectiveness of these two working modes is examined. We first designed a novel ESHP system capable of perfusing hearts in all three main perfusion modes. While hearts remained in LM for the bulk of the perfusion period, contractile evaluation was successfully demonstrated in both PSWM and PAWM. An adjustable afterload module was then developed and tested in order to decouple aortic pressure from changes in ventricular contractility, enabling prolonged perfusion in PAWM. With our module, we were able to demonstrate perfusion in PAWM across 6 hours for 3 different hearts while maintaining physiological aortic pressures. With the functionality of our system thus confirmed, transplantation experiments were undertaken to compare the predictive power of PSWM and PAWM. 5 porcine hearts donated after brain death (DBD) and 5 hearts donated after circulatory death (DCD) were perfused for 4 hours in LM, evaluated in both PSWM and PAWM, and transplanted into recipient pigs before being evaluated again. Correlating contractile parameters measured during ESHP and post-transplantation, measurements taken in PAWM showed greater predictive power than their PSWM counterparts. This augmentation of predictive power coupled with the ability to perfuse hearts in PAWM across extended perfusion periods serves to demonstrate our multimodal perfusion system as a promising step towards the optimization of donor heart preservation and evaluation during ESHP.