On the Possible Interaction Mechanism between Collateral Vessels and Restenosis

Several clinical studies and their meta-analysis suggest that developed collateral vessels in the heart correlate to an increased risk of in-stent restenosis. The possible physiological interaction between the collateral development and in-stent restenosis is investigated in this study. Based on existing publications, a hypothesis is suggested that the increased risk of in-stent restenosis is caused by a decrease in flow speed in the stented area, which lowers the wall shear stress there and causes a more severe tissue growth. For testing this hypothesis, an analytical model based on the hydro-electrical analogy is used. From this model, flow through the ischemic region is obtained for varying severity of stenosis and collateral flow indexes. The results suggest that even rather low collateral flow index has a considerable effect on the flow through restenosed artery for physiologically significant stenosis. This change in flow can indeed affect the wall shear stress and change the growth dynamics, so it might be necessary to account for it in models of in-stent restenosis.