Can collateral flow index have an influence on restenosis growth dynamics?

Collateral blood vessels have been statistically linked to a higher probability of repeat stenosis, but these data are not conclusive. Therefore, the aim of this research is to study a possible hydrodynamic pathway for stenosed coronary arteries for two scenarios: in absence of collaterals and in presence of collaterals with different collateral flow indices. For this in this study, we utilised an analytical model and a numerical model for studying this pathway. First, we performed an analytical calculation for the arterial bifurcation with a stenosis and a collateral vessel. Then, we carried out a numerical calculation using an existing numerical model for the same topology. Thus, we obtained the data characterizing the dependence of the wall shear stress on the stenosis degree for various Y-topology cases (without collaterals, and with different collateral flow indices). Then, based on the numerical model, we calculated the dependence of the wall shear stress on the stenosis degree for the physiology-based left coronary artery topology (without collaterals, and with different collateral flow indices). Moreover, to choose the stenosis location to study in the model, we used stent placement frequency statistics, based on data accumulated in clinical practice. As a result, analysis of the obtained data showed that for the structures studied in this work, collateral flow index does not affect the dynamics of restenosis. Thereby, the presence of collateral vessels is unlikely to have an influence on restenosis growth dynamics, and the link is likely purely statistical or follows a different pathway.