ESTIMATION OF FLOW-INDUCED BLOOD DAMAGE IN BIOMEDICAL DEVICES

Abstract

Biomedical devices are widely used in modern medicine to repair or replace various elements of the cardiovascular system. Unfortunately, in many cases, these devices cause dangerous pathological complications triggered by non-physiological conditions, such as undesired shear stress. The ability to predict blood damage induced by the destructive shear stresses within these devices is critical towards device design optimization process. Hemolysis and platelet activation are two major factors that cause device-related complications or device failure. Currently, no general, accurate predictive mathematical model of blood damage has resulted from over 40 years collective efforts due to physiologic complexities associated with multiscale blood flow dynamics; there still remains a general overestimation of current modeling capabilities for blood damage predication. The objective of this study is to provide an effective means using computational fluid dynamics (CFD) method to quantitatively estimate blood damage level, and provide a first-order assessment of hemolysis or platelet activation caused by shear stress without resorting to complex mathematical models. Shear stress and exposure time are two parameters that are employed to characterize blood trauma by simply plotting them into a shear stress-exposure time blood damage plane. This method was verified by in-vitro experimental results of various oxygenators and blood pumps, and can be used to evaluate the hemolysis or platelet activation level caused by shear stress in a device, therefore easily to determine its applicability for long term clinical application.