Comparison of Instantaneous Wave-Free Ratio (iFR) and Fractional Flow Reserve (FFR) with respect to Their Sensitivities to Cardiovascular Factors: A Computational Model-Based Study

Figure 1

Schematic description of 0-1-D multiscale modeling of the coronary circulation coupled to the global cardiovascular system. Note that coronary branch arteries in the RCA and LCx territories were modeled but are not presented in the figure in order to save space. A stenosis was introduced in the middle segment of LAD, with blood pressure immediately distal to it () being monitored along with blood pressure at the aortic root () for the purpose of calculating iFR or FFR. More details of model development, parameter assignment, and numerical methods have been described in our previous studies [21, 22]. Abbreviations: LM, left main artery; LAD, left anterior descending coronary artery; LCx, left circumflex coronary artery; RCA, right coronary artery. Notations of main parameters: L, vascular inductance; R, vascular resistance; C, vascular compliance; E, elastance of cardiac chamber; P_it, intrathoracic pressure; P_im, intramyocardial tissue pressure.