  Stent implantation in coronary bifurcations presents unique challenges and
currently there is no universally accepted stent deployment approach. Despite
clinical and computational studies, to date, the effect of each stent
implantation method on the coronary artery hemodynamics is not well understood.
In this study the hemodynamics of stented coronary bifurcations under pulsatile
flow conditions were investigated experimentally. Three implantation methods,
provisional side branch (PSB), culotte (CUL), and crush (CRU), were
investigated using time-resolved particle image velocimetry (PIV) to measure
the velocity fields. Subsequently, hemodynamic parameters including wall shear
stress (WSS), oscillatory shear index (OSI), and relative residence time (RRT)
were calculated and the pressure field through the vessel was non-invasively
quantified. The effects of each stented case were evaluated and compared
against an un-stented case. CRU provided the lowest compliance mismatch, but
demonstrated detrimental stent interactions. PSB, the clinically preferred
method, and CUL maintained many normal flow conditions. However, PSB provided
about a 300% increase in both OSI and RRT. CUL yielded a 10% and 85% increase
in OSI and RRT, respectively. The results of this study support the concept
that different bifurcation stenting techniques result in hemodynamic
environments that deviate from that of un-stented bifurcations, to varying
degrees.
