Nowadays the provisional side branch (PSB) approach is the preferred coronary bifurcation stenting technique. It is usually concluded by the final kissing balloon (FKB) procedure which consists in the simultaneous expansion of two balloons in both the bifurcation branches. Several kinds of accesses to the side branch (SB) can be used to perform the FKB procedure resulting in different final geometrical configurations of both the artery and the implanted stent and, consequently, altered hemodynamic scenarios. Computational fluid dynamic investigations have been frequently used to study the influence of stent implantation on blood flow. However, due to the complexity of the geometry of stented arteries, the high computational cost required for this kind of simulation has strongly limited their use in both the clinical and the industrial field. Hence, the present study firstly focuses on the development of an efficient volume meshing method, which led us to obtain accurate results on three-dimensional complex geometries in the shortest time compatible with the computational resources available. A hybrid meshing strategy was chosen, using both tetrahedral and hexahedral elements. Then, this discretization method was applied on a stented coronary bifurcation to quantitatively examine the different hemodynamic scenarios provoked by a FKB inflation performed with a proximal or a distal access to the SB. Transient fluid dynamic simulations were performed to analyse both near-wall variables like the wall shear stresses acting on the arterial wall and bulk flow quantities such as velocity magnitude and helicity fields. The results prove that the percentage of area characterised by wall shear stress smaller than 0.5 Pa is lower in the case of the distal access (84.7 % versus 88.0 %). The velocity and helicity contour maps resulted to be better with this type of access, too. In conclusion, fluid dynamic simulations provided a valid tool to quantitatively support the clinical experience that suggests to perform the distal access instead of the proximal one during the PSB approach.

Computational fluid dynamics of stented coronary bifurcations studied with a hybrid discretization method

CHIASTRA, CLAUDIO;MORLACCHI, STEFANO;DUBINI, GABRIELE ANGELO;MIGLIAVACCA, FRANCESCO
2012-01-01

Abstract

Nowadays the provisional side branch (PSB) approach is the preferred coronary bifurcation stenting technique. It is usually concluded by the final kissing balloon (FKB) procedure which consists in the simultaneous expansion of two balloons in both the bifurcation branches. Several kinds of accesses to the side branch (SB) can be used to perform the FKB procedure resulting in different final geometrical configurations of both the artery and the implanted stent and, consequently, altered hemodynamic scenarios. Computational fluid dynamic investigations have been frequently used to study the influence of stent implantation on blood flow. However, due to the complexity of the geometry of stented arteries, the high computational cost required for this kind of simulation has strongly limited their use in both the clinical and the industrial field. Hence, the present study firstly focuses on the development of an efficient volume meshing method, which led us to obtain accurate results on three-dimensional complex geometries in the shortest time compatible with the computational resources available. A hybrid meshing strategy was chosen, using both tetrahedral and hexahedral elements. Then, this discretization method was applied on a stented coronary bifurcation to quantitatively examine the different hemodynamic scenarios provoked by a FKB inflation performed with a proximal or a distal access to the SB. Transient fluid dynamic simulations were performed to analyse both near-wall variables like the wall shear stresses acting on the arterial wall and bulk flow quantities such as velocity magnitude and helicity fields. The results prove that the percentage of area characterised by wall shear stress smaller than 0.5 Pa is lower in the case of the distal access (84.7 % versus 88.0 %). The velocity and helicity contour maps resulted to be better with this type of access, too. In conclusion, fluid dynamic simulations provided a valid tool to quantitatively support the clinical experience that suggests to perform the distal access instead of the proximal one during the PSB approach.
2012
Computational fluid dynamics; Hybrid mesh; Stenting procedures; Coronary bifurcations; Side branch access
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/654132
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