Flow separation in an artificial heart valve

Background

Patients with valvular heart diseases receive artificial heart valves. There are two basic types of artificial heart valves, mechanical valves and tissue valves (figure 1).

Mechanical valves, however, lead to blood clotting which is mainly induced by excessive shear stresses in the blood flow. These patients require lifelong anti-coagulant therapy which is an additional drawback in their quality of life and a disqualifying condition for some professions (e.g., pilots). But this type of valves last for a lifetime.

Artificial heart valves made from biological tissue (figure 2 & 3) do not suffer from these problems. However, they are less durable than mechanical heart valves and a re-operation may become necessary. 

The durability of artificial heart valves is tightly connected to the calcification of the valve leaflets (in a process similar to atherosclerosis) which leads to structural valve degeneration. A potential cause for this calcification are flow separation phenomena at the trailing edge of the valve leaflets, particularly under high-output conditions (young patient, sports, etc.).

Project Description

In this collaborative project with the University Hospital Zurich (Dr. Thomas Syburra, Prof. Michele Genoni, Klinik für Herz- und Gefässchirurgie) the flow separation phenomena in artificial biological heart valves shall be studied. In a first step, this project shall assess the potential for flow separation by simple experimental means. To this end, the heart valve will be integrated in a water circuit. It shall then be determined under what flow conditions separation (fluttering?) can be observed.

See also the student project Particle deposition in an artificial heart valve.

Prerequistites

• interest in biomedical engineering
• strong background in fluid dynamics

Contact

Dr. Dominik Obrist
Prof. Patrick Jenny