Background: Fractional flow reserve (FFR) is the gold standard for invasive assessment of myocardial ischemia in the diagnosis of coronary artery disease (CAD). Traditionally, FFR is measured using pressure wires during coronary angiography. Recently, computational fluid dynamics (CFD) has been applied to calculate FFR noninvasively and efficiently. However, conventional CFD methods often require complex computations. This study aimed to evaluate simplified analytical conditions for CFD-based FFR calculations.

Methods and Results: We enrolled 25 patients with angina who underwent coronary computed tomography (CT), coronary angiography, and invasive FFR measurement. Using 3D data reconstructed from CT, CFD analysis was conducted with a vascular volume ratio-based boundary condition. Results demonstrated a Pearson correlation coefficient r of 0.98 and a concordance correlation coefficient CCC of 0.982, with an error margin within ± 5%. Additionally, one case with signal drift during invasive measurement achieved comparable results using this CFD approach.

Conclusion: This study confirmed the utility of a CFD method utilizing vascular volume ratios for non-invasive FFR calculations. This simplified approach facilitates straightforward and accurate FFR assessment, offering a potential novel tool for early CAD detection and treatment planning.