A MODEL OF BLOOD INTERACTION WITH OPTICAL-FLUID GUIDE FOR LASER ANGIOPLASTY

A mathematical model is developed to describe the flow and mixing of b lood and optical fluid used in liquid-guided light for laser angioplas ty. The model is based on a two-fluid formulation in which separate tr ansport equations are solved for the blood and the optical fluid. Empi rical relations, established in prior work, are used to represent inte rfluid transport of momentum. Both steady and phasic inflow conditions are considered. Parametric calculations are performed showing effect of relative flow rates of blood and optical fluid, on the mixing pheno mena. The relative velocity considered (based on average blood velocit y) ranged from 0.08 to 0.28 m/sec. No allowance has been made for abla tion of the plaque. The predicted results include spatial distribution of the velocity field and the existence probabilities (volume fractio ns) that provide a measure of the extent of mixing between the fluids. It is found that the degree of mixing is adversely affected by the re lative inflow velocity between blood and optical fluid and the pulsati lity of blood inflow. Deep penetration of the optical fluid is predict ed at high relative velocity and at the end of diastolic and early sys tolic stages of the cardiac cycle.