The study of hemodynamics in an animal model simulating coronary stenosis has been limited due to the lack of a safe, accurate and reliable technique for creating an artificial stenosis. Creating artificial stenosis using occluders in an open-chest procedure has often caused myocardial infarction (MI) or severe injury to the vessel resulting in high failure rates. To minimize these issues, closed-chest procedures with internal balloon obstruction are often used to create an artificial stenosis. However, the hemodynamics in a blood vessel with internal balloon obstruction versus a physiological stenosis has not been compared. Hence, the aim of this research is to develop a relationship to predict the balloon obstruction equivalent to that of a physiological stenosis. The pressure drop in a balloon obstruction was evaluated and compared with that in a physiological stenosis. It was observed that the flow characteristics in balloon obstructions are more viscous dominated, whereas those in physiological stenoses are momentum dominated. Balloon radius was iteratively varied using a Design of Experiments (DOE) based optimization method to obtain a pressure drop equal to that of a physiological stenosis at mean hyperemic flow rates. A linear relation was obtained to predict equivalent balloon obstruction for a physiological stenosis. Further, the details were verified with our in vivo (animal) study data.
Keywords: Internal balloon obstruction; physiological stenosis; pressure drop.