Image-Based Modeling of Blood Flow in Human Coronary Arteries With and Without Bypass Grafts During Rest and Simulated Exercise

The number of patients with coronary artery disease continues to rise, with approximately 469,000 coronary bypass procedures in 2005 alone [1]. A priori knowledge of the flow features within the coronary vascular system could prove useful in predicting flow changes due to coronary bypass surgery. Image-based modeling and 3-D computational simulations could be used to compute flow and pressure in a patient-specific manner. However, modeling coronary flow requires knowledge of the intramyocardial pressure that compresses coronary vessels, resulting in decreased flow in systole and increased flow in diastole. Left ventricular pressure can provide an estimate to intramyocardial pressure, but the aortic pressure and left ventricular pressure must be coupled in systole when the aortic valve is open. Previously, we have developed a method to couple a lumped-parameter heart model to the inlet of a 3-D model to compute aortic and ventricular pressure [2]. In this study, we use the lumped-parameter heart model and computational fluid dynamics to calculate flow dynamics in a patient model with coronary artery bypass grafts.