Computers in Biology and Medicine 32 (2002) 329–344 www.elsevier.com/locate/compbiomed Numerical modeling of the ow in stenosed coronary artery. The relationship between main hemodynamic parameters E. Shalman a; b , M. Rosenfeld a ; * , E. Dgany b , S. Einav a a Faculty of Engineering, Tel-Aviv University, 69978 Tel Aviv, Israel b Florence Medical Ltd., Dereh Hasharon St., Kfar Sava, Israel Received 3 November 2000; accepted 2 October 2001 Abstract The severity of coronary arterial stenosis is usually measured by either simple geometrical parameters, such as percent diameter stenosis, or hemodynamically based parameters, such as the fractional ow reserve (FFR) or coronary ow reserve (CFR). The present study aimed to establish a relationship between actual hemodynamic conditions and the parameters that dene stenosis severity in the clinical setting. We used a computational model of the blood ow in a vessel with a blunt stenosis and an autoregulated vascular bed to simulate a stenosed blood vessel. A key point in creating realistic simulations is to properly model arterial autoregulation. A constant ow regulation mechanism resulted in CFR and FFR values that were within the physiological range, while a constant wall-shear stress model yielded unrealistic values. The simulation tools developed in the present study may be useful in the clinical assessment of single and multiple stenoses by means of minimally invasive methods. ? 2002 Elsevier Science Ltd. All rights reserved. Keywords: Computational uid dynamics; Coronary ow reserve; Fractional ow reserve; Vascular bed index 1. Introduction Arterial stenosis is one of the most serious forms of arterial disease. A number of studies have been devoted to the analysis of parameters intended to estimate the degree of stenosis severity. Instead of simple geometrical parameters, such as percent diameter stenosis, hemodynamically based parameters were suggested and tested clinically. The hemodynamic parameters that are widely used in clinical practice are the pressure-based myocardial fractional ow reserve (FFR) and the ow-based coronary ow reserve (CFR). Other hemodynamic parameters, such as the relative ow velocity reserve (CVR), are either still being tested [1] or rarely used, due to low specicity. ∗ Corresponding author. Tel.: +972-3-670-8534; fax: +972-3-640-7334. E-mail address: rosenf@eng.tau.ac.il (M. Rosenfeld). 0010-4825/02/$ - see front matter ? 2002 Elsevier Science Ltd. All rights reserved. PII:S0010-4825(01)00033-6