Investigation of hemodynamics in the assisted isolated porcine heart.

Background: Currently, the interaction between rotary blood pumps (RBP) and the heart is investigated in silico, in vitro, and in animal models. Isolated and defined changes in hemodynamic parameters are unattainable in animal models, while the heart-pump interaction in its whole complexity cannot be modeled in vitro or in silico. Aim: The aim of this work was to develop an isolated heart setup to provide a realistic heart-pump interface with the possibility of easily adjusting hemodynamic parameters. Methods: A mock circuit mimicking the systemic circulation was developed. Eight porcine hearts were harvested using a protocol similar to heart transplantation. Then, the hearts were resuscitated using Langendorff perfusion with rewarmed, oxygenated blood. An RBP was implanted and the setup was switched to the "working mode" with the left heart and the RBP working as under physiologic conditions. Both the unassisted and assisted hemodynamics were monitored. Results: In the unassisted condition, cardiac output was up to 9.5 L/min and dP/dt(max) ranged from 521 to 3621 mmHg/s at a preload of 15 mmHg and afterload of 70 mmHg. With the RBP turned on, hemodynamics similar to heart-failure patients were observed in each heart. Mean pump flow and flow pulsatility ranged from 0 to 11 L/min. We were able to reproduce conditions with an open and closed aortic valve as well as suction events. Conclusions: An isolated heart setup including an RBP was developed, which combines the advantages of in silico/vitro methods and animal experiments. This tool thus provides further insight into the interaction between the heart and an RBP.