Alternative Systems

This track of Zurich Heart aims at disruptive innovations and technologies to facilitate radically new artificial heart designs and assist device technologies.

Five focus points have been defined: Development of hybrid membranes, soft pumps, tissue-engineered heard valves and interfaces, fontan assist, and  computer models for optimization of pump design. 

 

Hyperelastic Hybrid Membrane for Biomimetic Blood Propulsion

Endothelial Cells

Prof. Edoardo Mazza (ETH), Prof. Paolo Ermanni (ETH), Prof. Stephen J. Ferguson (ETH), Prof. Simon P. Hoerstrup (UZH), Dr. Katharina Maniura (Empa), Prof. Mirko Meboldt (ETH), Prof. Dimos Poulikakos (ETH), Dr. René Rossi (Empa), Prof. Viola Vogel (ETH), Prof. Karin Würtz (ETH)

The aim is to generate a highly deformable hybrid membrane consisting of a synthetic substrate covered by an endothelial cell layer. This bio-composite material system will integrate a living biological layer into a mechanical device. It could form the basis of a 100% haemocompatible blood pump. For this application, the hybrid membrane is required to resist cyclic deformation and shear stresses from blood flow. Ensuring long-term integrity and functionality of the endothelium attached to the highly deformable substrate exposed to flow represents the major challenge of the new system. Several approaches are explored ranging from multi-layer tissue engineered constructs, to electro-spun scaffolds, to topography optimization and cell binding protein inclusions. The design of the pump is optimized in order to minimize mechanical loading of the hybrid membrane.

Hybrid membrane

 

Soft Pumps

Soft Pumps

Prof. Wendelin Stark (ETH)

Current widely implanted artificial blood pumps are made of rigid materials and produce continuous blood flow. However, the human heart is soft and gives a pulsatile blood flow. Thus, we propose that an ideal artificial heart would be made of soft materials only and mimic the human heart as closely as possible to give the most physiological blood flow possible.

We investigate the development and use of soft pumps for heart replacement therapy. The first generation of soft total artificial heart (sTAH) prototypes were manufactured using a 3D-printing lost wax-cast technique. These silicone sTAHs, driven by pneumatic actuation, gave physiological pulsatile blood flow but showed a limited lifetime. The second-generation prototypes were built using the rubber compression molding technique. These prototypes showed increased pumping performance and increased lifetime. In a next step, we aim at using a biocompatible polymer and an improved artificial heart design to enhance the pumping performance and the longevity of the sTAH. These next development goals should give a true alternative to current continuously pumping support devices.

 

Tissue-Engineered Hybrid Heart Valves and Interfaces

Hybrid heart walve

Prof. Simon P Hoerstrup (UZH)

Tissue engineering technologies with human cells aim at the in vitro creation of novel living heart valves with repair and regeneration capacity. Such living valves will be designed to approximate native heart valves as to biomechanical performance and physiological surfaces.

To improve the integration of heart assist devices into the host organism, tissue engineering technologies will be used to create more physiological device-to-tissue interfaces at the level of vascular connection (engineered vascular grafts) and device to body cavity interface (engineered pericardium). Novel in situ tissue-engineered methodologies using endogenous cellular repopulation strategies will be a particular focus.

 

Computational Model for Designing Heart Assist Devices

Visualization of a computational model
Simplified biventricular geometry with arrows indicating muscle fiber directions. Computations are done in LiveV (www.lifev.org).

Prof. Patrick Jenny (ETH)

Designing and optimizing heart assist devices is complicated by a lack of parameter data and limited experimental capabilities. Thus, computational models can step in to gain a better understanding of the fluid and structure mechanics of the heart.

This project aims at developing a fluid-structure-interaction model, which allows for testing and optimization of medical devices. The structure of the heart is represented by a finite element model, whereas the blood circulation is represented by a hydraulic circuit. By imposing boundary conditions on the pericardium we can then investigate how assist devices influence the contraction and cardiac output.

The model is mainly thought to be used for the development of assist devices, which directly act on the heart's surface.

 

Fontan Assist

Hypoplastic left heart syndrome
Hypoplastic left heart syndrome
Hypoplastic left heart syndrome. (Wikimedia)

Prof. Michael Hübler (UZH/Kispi), Prof. Mirko Meboldt (ETH), Dr. Marianne Schmid Daners (ETH), Prof. Vartan Kurtcuoglu (UZH)

This initiative has the goal to identify new approaches to improve the situation of children born with only a single ventricle heart instead of two. The single ventricle must pump the blood through the body as well as the lungs and this has severe consequences for the life and survival of affected children. The French heart surgeon François Fontan established a surgical procedure to build a new blood circulation in which the venous blood is bypassed directly into the lungs, omitting the heart. Thus, the single ventricle heart takes over the systemic circulation.

With the help of simulators, the state-of-the-art of the current procedure shall be examined and the complex environment, from neonates to adults explored. This interdisciplinary research project is highly clinically oriented. The new approach for heart surgery and, where appropriate, mechanical support shall fundamentally improve the treatment of the children and future adults.