Document Type

Thesis

Date of Award

5-31-1986

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering Committee

First Advisor

Basil Baltzis

Second Advisor

David S. Kristol

Third Advisor

Peter Engler

Abstract

The present study involves the use of an accelerated fatigue testing system*, and a pulse duplicator (heart simulator)*, to evaluate the hydrodynamic characteristics of cardiac bioprostheses.

The hydrodynamic performance of these prosthetic valves is compared when tested using each machine, in order to assess the determining conditions that exist for each case, and try to correlate them.

Pressure drop and pulsatile flow across valves are measured, using a real-time on-line data acquisition system, which includes, in addition to the fatigue tester and the pulse duplicator, a DC amplifier, an analog-to-digital converter and a digital microcomputer. Special acquisition software has been developed for the purpose of this study. The effect of machine pulse rate (heart rate) and pump stroke (stroke volume), on different parameters such as flow rate, pressure, regurgitation fraction, negative (closing) volume, effective orifice area, discharge coefficient, performance index, etc, is studied.

The results are compared with existing theoretical predictions, and the importance of each one of the above mentioned parameters is discussed in connection to these predictions. The relevance of the regurgitation or back-flow fraction is particularly stressed.

The findings of this study provide some answers to important questions regarding the hemodynamic performance of bioprostheses. In addition, the results suggest further steps to be undertaken for a deeper understanding of cardiac valve hydrodynamics at accelerated conditions.

*- This equipment is part of Dr. Gabbay's Cardiothoracic Research Laboratory at the New Jersey Medical School.

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