Impacts on hemodynamics of different bifurcation coronary stent configurations

Abstract

Percutaneous coronary intervention such as implantation of a stent (stenting) is the modern gold standard for coronary revas-cularisation. Stenting for a simple lesion has become a common procedure and is highly successful, but stenting for bifurcation lesions is more difficult and requires multiple stent implantations. The presence of the stent struts partially occludes blood flow from the main vessel to the side branch and leads to chaotic flow. As a result, bifurcation coronary stenting is often associated with dreaded complications like in-stent restenosis and thrombosis. Computational fluid dynamics (CFD) simulations were conducted on the classical T-stenting (TS) and reverse Tstenting (R-TS) techniques under pulsatile physiological conditions. The effects of TS and R-TS techniques on the changes in hemodynamics were systemically analysed. Removing the stent struts at the side branch (SB) ostium in the R-TS technique enlarges the recirculation bubble at the entrance of the SB, but reduces the area of non-physiological mean wall shear stress (WSS < 0.5 Pa) at baseline flow condition. However, the larger recirculation bubble results in a greater area of low WSS at induced hyperemia. The presence of the stent struts in the TS technique also reduces blood flow into the SB and creates low velocity regions in the vicinity of the stent struts. The differences in blood flow rate between the TS and R-TS techniques diminishes at induced hyperemia.