M Giersiepen

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The hemodynamics of heart valve prostheses can be reproducibly investigated in vitro within circulatory mock loops. By measuring the downstream velocity and shear stress fields the shear stresses which are clinically responsible for damage to platelets and red blood cells can be determined. The mechanisms of damage and the effects of shear stresses on blood(More)
For the design of aortic valve prostheses with a separation-free flow field and minimum pressure drop the geometry of the aortic root is of high importance, since an appropriate adjustment of the prostheses to the surrounding geometry could largely reduce the risk of thromboembolic complications. For the investigation of the geometry of the aortic root 604(More)
Based on hot-film anemometry, point velocity measurements in the total cross sectional area 1 and 2 diameters downstream of: Björk-Shiley Standard, Convex-Concave and Monostrut, Hall-Kaster (Medtronic-Hall), St. Jude Medical and Starr-Edwards Silastic Ball aortic valves were made. The spatial distribution of Reynolds Normal Stresses (RNS) was visualized(More)
In a pulsatile flow model aortic Björk-Shiley Standard, Convex-Concave and Monostrut valves were investigated together with the Hall-Kaster (Medtronic-Hall), St Jude Medical and Starr-Edwards Silastic Ball valve using hot-film anemometry. Three-dimensional visualization of average systolic Reynolds normal stresses (RNS) reflected the design of the valves.(More)
Since artificial heart valve related complications such as thrombus formation, hemolysis and calcification are considered related to flow disturbances caused by the inserted valve, a thorough hemodynamic characterization of heart valve prostheses is essential. In a pulsatile flow model, fluid velocities were measured one diameter downstream of a Hancock(More)
Velocity fields downstream of 27 mm Björk-Shiley Standard, Björk-Shiley Convex-Concave, Björk-Shiley Monostrut, Hall-Kaster (Medtronic-Hall), St. Jude Medical and Starr-Edwards Silastic Ball aortic valves were studied in a pulsatile mock circulation. Stroke volume was 70 cm3 and frequency 71 min-1 and 88 min-1. Fluid velocity was measured by a catheter(More)
Patients with an implanted mechanical heart valve sometimes experience the closing sounds of the valve as disturbing. To study the generation of valve sounds in general, a pulse duplicator study was carried out, testing eight commonly used types of prosthetic valves in the aortic position. Pulse rate was set at 70 beats/min, stroke volume at 70 ml and mean(More)