CT image-based patient-specific computational model to assess hemodynamics of Myocardial Bridge

Myocardial Bridges (MB) are inborne anatomic anomaly often localized in the left anterior descending coronary artery. Although they are usually asymptomatic, they have sometimes been associated with angina, myocardial ischemia, acute coronary syndromes, and even sudden death. Numerous experimental studies have been done to unveil the pathophysiology of MBs and their clinical evaluation. However, the hemodynamic impact of myocardial bridging and underlying mechanism remains unclear. The goal of this study was to build a computed tomography angiography (CTA)-based computational model to analyze the impact of MB on hemodynamic characteristics and its association with myocardial ischemia. A 3D geometry of the left anterior descending coronary artery was constructed from CT images along with angiogram of a patient with MB. Influence of different sizes of myocardial bridge and different boundary conditions on intracoronary flow characteristics was investigated through computational fluid dynamic (CFD) analysis. Our results demonstrated that changing BCs at both inlet and outlet influenced the pressure magnitude. However, the velocity was only affected by imposed inlet BCs. Different levels of lumen diameter reduction resulted in changes in the flow velocity within the bridge and pressure at the inlet. Pressure drop along the bridge increased as the lumen diameter decreased. Additionally we showed that imposing BCs obtained at normal physiologic condition, did not differentiate between FFR and dFFR. This study was the first one that developed a realistic computational model to simulate the flow in coronary arteries understand more about bridged coronary arteries. Further investigating to validate our results will lead to a cost effective approach to help cardiologists in clinical decision making regarding the treatment options.