Forschung

This project aims at optimizing blood flow in ventricular assist devices (VADs) with respect to hemodynamic performance, blood damage and thrombosis. To that end, we will on the one hand develop a computational framework to probe the local hemodynamics in VADs under operating conditions, and on the other develop an in vitro experimental setup to elucidate and quantify the behavior of erythrocytes under high shear stresses. Ultimately, the experimental data will be used to refine existing blood damage models and, once integrated into our computational framework, to accurately predict blood damage associated with a given VAD design.

This venture is part of the Zurich Heart Project, which aims at the development of next generation VADs.

Background

Heart failure (HF) is a global health problem with more than 23 million cases per year. Patients suffer from extreme fatigue and weakness because the heart is not able to supply enough blood to perfuse the body with oxygen. Heart failure patients experience a continuous deterioration of their condition, and the five year mortality lies between 45 and 60%. Patients with end-stage HF require transplantation. However, due to the lack of sufficient donor hearts, ventricular assist devices (VADs) are increasingly implanted as a destination therapy. These are still associated with a number of complications including bleeding, thrombosis, hemolysis, and infection. The Zurich Heart Project, a collaborative endeavor between University Hospital, University and ETH Zurich addresses those issues and aims at the development of a next generation ventricular assist device incorporating several new technologies. The Interface Group is part of this initiative, focusing on the fluid dynamic aspects of the new VAD.
Fluid dynamics critically influence the biophysical interaction between VAD and blood. Areas of stagnating flow harbor the risk of increased thrombogenesis, while regions of high shear stress can lead to blood damage. We have developed a computational fluid dynamic (CFD) framework to characterize the hemodynamics with a VAD under operating conditions and probe the mechanical stress history of individual blood cells.

Project goals

This preliminary computational framework will be further developed in conjunction with in vitro experiments to:

• Include blood damage models in computational fluid dynamics simulations to characterize the hemolysis and thrombosis potential of given VAD designs
• Better understand erythrocyte behavior under high shear stresses and thereby establish an accurate blood damage model
• Optimize VAD designs with respect to hemodynamics and blood damage