We have developed a novel image measurement technique called paint erosion method (PEM) to estimate wall shear stress (WSS). In the PEM, the WSS is estimated from the paint erosion rate obtained by the instantaneous change of light transmission power on the image. In this study, we attempted to depict WSS distribution of the diaphragm-type pulsatile blood pump in our total artificial heart by the PEM, and further compared the obtained WSS distribution with in vivo thrombus deposition area. The average WSS contour map inside the blood pumps were successfully obtained by using the PEM, and in vivo thrombus deposition area coincided with the low WSS of less than 2.7 Pa. We concluded that WSS mapping based on the PEM provides useful information for predicting the preference area of in vivo thrombus formation in a pulsatile blood pump and facilitates improving its antithrombogenicity from the viewpoint of flow dynamics.
