Qualitative and Quantitative Characterization of
Arterial Stenosis: Pressure and Flow Wave Analysis

Zehavia Ovadia-Tirosh, Prof. Michael Qualitative
and Quantitative Eldar
Neufeld Cardiac Research Inst., Sheba Medical Center,
Tel Aviv University

Dr. Uri Zaretsky
Dept of Bio-Mechanical Engineering, Fleischman Faculty of Engineering,
Tel Aviv University

Arterial stenosis, particularly coronary arterial stenosis, is the main cause of morbidity and mortality in the western world. Since coronary stenosis reduces myocardial blood supply and may lead to ischemia, cardiac insufficiency and myocardial infarction, research aimed at characterization and evaluation of the severity of arterial stenosis is of great importance. To the best of our knowledge, other than this research, no other study which examines arterial pressure and flow waves and their modulation by arterial stenosis has yet been reported.

There are three specific goals to our study:

1. To characterize the effects of different grades of stenosis on the pattern of pressure and flow waves in vitro (plastic and rubber tubes and ex-vivo arteries) and in-vivo (pig carotid) systems.
2. To investigate the changes in pressure and flow waves caused by varying the distance between the stenosis and the intra-arterial pressure gauge.
3. To develop a means which will enable characterization of the severity and the location of arterial stenoses by intra-arterial measurement of blood pressure and flow waves.

Preliminary results indicate changes in the pressure and flow waves frequency components, dependent on the degree and location of the stenosis. As our research continues, we expect to broaden our knowledge and understanding of blood vessel physiology and physiopathology and to examine the possibility of improving the characterization of arterial stenosis. At present coronary angiography is limited to the demonstration of relatively significant stenoses, giving only a crude estimation of their actual severity. Furthermore, relatively little is known about the interrelation between the vessel wall characteristics and the grade of stenosis and its effects on the pattern of pressure and flow waves in the arterial tree.