Numerical Simulation and Clinical Implications of Stenosis in Coronary Blood Flow

Fractional flow reserve (FFR) is the gold standard to guide coronary interventions. However it can only be obtained via invasive angiography. The objective of this study is to propose a noninvasive method to determine FFR(CT) by combining computed tomography angiographic (CTA) images and computational fluid dynamics (CFD) technique. Utilizing the method, this study explored the effects of diameter stenosis (DS), stenosis length, and location on FFR(CT). The baseline left anterior descending (LAD) model was reconstructed from CTA of a healthy porcine heart. A series of models were created by adding an idealized stenosis (with DS from 45% to 75%, stenosis length from 4 mm to 16 mm, and at 4 locations separately). Through numerical simulations, it was found that FFR(CT) decreased (from 0.89 to 0.74), when DS increased (from 45% to 75%). Similarly, FFR(CT) decreased with the increase of stenosis length and the stenosis located at proximal position had lower FFR(CT) than that at distal position. These findings are consistent with clinical observations. Applying the same method on two patients' CTA images yielded FFR(CT) close to the FFR values obtained via invasive angiography. The proposed noninvasive computation of FFR(CT) is promising for clinical diagnosis of CAD.