Application of the Multi-Artery FFR Method to Some Stenotic 3-Artery Coronary Configurations

The basic single-artery FFR method currently used in the PCI practice cannot resolve MVD cases with considerable stenosis-stenosis interactions. A close examination of the FAME study reveals that stenotic LMCA cases were excluded, turning each of the stenotic major epicardial arteries LAD, LCx and RCA into an independent simple SVD case and each was treated as such by the basic FFR method. The advanced Multi-artery FFR method developed by me, handles trans-arterial stenosis-stenosis interactions and resolves stenotic coronary 3-artery configurations. In this work the configuration consists of sizable arteries: Artery 1 is functionally a stenotic `conductance` artery with proximal aortic pressure, Artery 2 is stenosis-free end-artery (FFRtrue(2)=1.00) and Artery 3 a stenotic end-artery. The actual FFR of each artery (denoted FFRreal) is not equal to its basic FFRtrue, because of stenosis-stenosis interactions. FFRreal depends on FFRtrue(1), FFRtrue(3) and on δ, the ratio of the microvascular resistances of the end-arteries. FFRreal dependence on δ is low for 0.6≤δ≤1.7 (ΔFFRreal=±0.02) in the low and intermediate stenosis severity ranges. δ=1 and the same formulas can be therefore used going from one patient to another. Each FFRreal is a function of only FFRtrue(1) and FFRtrue(3). The current FFRtrue values can be derived from the measured intracoronary pressures. Being a function of 2 variables, each FFRreal can be obtained from a pre-calculated FFRreal table (with δ=1). Each FFRreal is given in a table in which the rows are labeled by FFRtrue(1) and the columns by FFRtrue(3) in the range 0.30≤ FFRtrue≤1.00. By crossing appropriate rows and columns, the tables yield current FFRreal values and also outcomes of possible revascularizations (by putting FFRtrue=1.00 in the tables, for revascularized artery). To conclude, using the tabular technique the practitioner can obtain the optimal resolution of coronary 3-artery stenotic configurations in real time during the PCI procedure.