Flow Patterns at Stented Coronary Bifurcations

Abstract

Background— The ideal bifurcation stenting technique is not established, and data on the hemodynamic characteristics at stented bifurcations are limited. Methods and Results— We used computational fluid dynamics analysis to assess hemodynamic parameters known affect the risk of restenosis and thrombosis at coronary bifurcations after the use of various single- and double-stenting techniques. We assessed the distributions and surface integrals of the time averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (t r ). Single main branch stenting without side branch balloon angioplasty or stenting provided the most favorable hemodynamic results (integrated values of TAWSS=4.13·10 −4 N, OSI=7.52·10 −6 m 2 , t r =5.57·10 −4 m 2 /Pa) with bifurcational area subjected to OSI values >0.25, >0.35, and >0.45 calculated as 0.36 mm 2 , 0.04 mm 2 , and 0 mm 2 , respectively. Extended bifurcation areas subjected to these OSI values were seen after T-stenting: 0.61 mm 2 , 0.18 mm 2 , and 0.02 mm 2 , respectively. Among the considered double-stenting techniques, crush stenting (integrated values of TAWSS=1.18·10 −4 N, OSI=7.75·10 −6 m 2 , t r =6.16·10 −4 m 2 /Pa) gave the most favorable results compared with T-stenting (TAWSS=0.78·10 −4 N, OSI=10.40·10 −6 m 2 , t r =6.87·10 −4 m 2 /Pa) or the culotte technique (TAWSS=1.30· 10 −4 N, OSI=9.87·10 −6 m 2 , t r =8.78·10 −4 m 2 /Pa). Conclusions— In the studied models of computer simulations, stenting of the main branch with our without balloon angioplasty of the side branch offers hemodynamic advantages over double stenting. When double stenting is considered, the crush technique with the use of a thin-strut stent may result in improved immediate hemodynamics compared with culotte or T-stenting.