Functional Assessment of Stenotic Coronary Artery in 3D Geometric Reconstruction From Fusion of Intravascular Ultrasound and X-Ray Angiography

Abstract

We aimed to present an alternative method for calculating fractional flow reserve (FFR) from 3-D reconstruction of a coronary artery, based on coronary (X-ray) angiography and intravascular ultrasound (IVUS), to evaluate the ischemic-risk of stenosis and the relationship between FFR and geometrical features of the coronary lesion. The reconstruction of the 3-D catheter trajectory was obtained by the vertical intersection of spatial surfaces which were derived from the 2-D catheter curves in the angiography plane. Computational fluid dynamics was applied to calculate the hemodynamics in the coronary arteries and coronary flow-based FFR (fFFR) was obtained. Twenty-two stenotic coronary arteries were included in this paper for the evaluation of the proposed method. Good correlation between fFFR and the measured pressure wire-derived FFR was found ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">F</i> = 0.916 and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> < 0.01). Based on our computer modeling, the fFFR values correlated negatively with the severity of the stenosis ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> = −0.784 and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> < 0.01). However, fFFR had no significant correlation with coronary curvature, lesion length, and angle. Our method therefore provides a coronary vascular model-based means for computing FFR, and makes full use of the advantages of IVUS examination to diagnose the diseases.