Limits...
Hemodynamics in Idealized Stented Coronary Arteries: Important Stent Design Considerations.

Beier S, Ormiston J, Webster M, Cater J, Norris S, Medrano-Gracia P, Young A, Cowan B - Ann Biomed Eng (2015)

Bottom Line: Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG.For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts.In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand. s.beier@auckland.ac.nz.

ABSTRACT
Stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. The purpose of this study was to evaluate the impact of stent design on wall shear stress (WSS), time average WSS, and WSS gradient (WSSG), in idealized stent geometries using computational fluid dynamics. Strut spacing, thickness, luminal protrusion, and malapposition were systematically investigated and a comparison made between two commercially available stents (Omega and Biomatrix). Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG. Local hemodynamics worsened with luminal protrusion of the stent and with stent malapposition, adverse high WSS and WSSG were identified around peak flow and throughout the cardiac cycle respectively. For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts. In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

No MeSH data available.


Related in: MedlinePlus

Strut size: (a) Omega geometry with 81 µm (left) and 120 µm (right) strut size, (b) WSS, (c) TAWSS contour for 81 µm (left) and 120 µm (right) strut size, (d) histogram of TAWSS distribution and (e) percentage areas of low WSS (<0.5 Pa, left) and high WSSG (>200 Pa/m, right) over the cardiac cycle for the 81 µm (blue) and 120 µm (green) Omega geometry.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4764643&req=5

Fig4: Strut size: (a) Omega geometry with 81 µm (left) and 120 µm (right) strut size, (b) WSS, (c) TAWSS contour for 81 µm (left) and 120 µm (right) strut size, (d) histogram of TAWSS distribution and (e) percentage areas of low WSS (<0.5 Pa, left) and high WSSG (>200 Pa/m, right) over the cardiac cycle for the 81 µm (blue) and 120 µm (green) Omega geometry.

Mentions: Table 2 summarizes the area-averaged statistical quantities of the TAWSS distribution and the percentage area of TAWSS < 0.5 Pa. Figures 3a, 4e, 5a, and 6a show the percentage area meeting the adverse hemodynamic criteria of low WSS (<0.5 Pa), and high WSSG (>200 Pa/m) at different times points in the cardiac cycle. Endothelial cells respond to shear stress26 and ideally cover the stent surface area within a few days after PCI.16 For this reason, the area considered is vessel and stent surface plus 5 mm of vessel on each side of the stent to capture any proximal or distal flow disturbances.Table 2


Hemodynamics in Idealized Stented Coronary Arteries: Important Stent Design Considerations.

Beier S, Ormiston J, Webster M, Cater J, Norris S, Medrano-Gracia P, Young A, Cowan B - Ann Biomed Eng (2015)

Strut size: (a) Omega geometry with 81 µm (left) and 120 µm (right) strut size, (b) WSS, (c) TAWSS contour for 81 µm (left) and 120 µm (right) strut size, (d) histogram of TAWSS distribution and (e) percentage areas of low WSS (<0.5 Pa, left) and high WSSG (>200 Pa/m, right) over the cardiac cycle for the 81 µm (blue) and 120 µm (green) Omega geometry.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4764643&req=5

Fig4: Strut size: (a) Omega geometry with 81 µm (left) and 120 µm (right) strut size, (b) WSS, (c) TAWSS contour for 81 µm (left) and 120 µm (right) strut size, (d) histogram of TAWSS distribution and (e) percentage areas of low WSS (<0.5 Pa, left) and high WSSG (>200 Pa/m, right) over the cardiac cycle for the 81 µm (blue) and 120 µm (green) Omega geometry.
Mentions: Table 2 summarizes the area-averaged statistical quantities of the TAWSS distribution and the percentage area of TAWSS < 0.5 Pa. Figures 3a, 4e, 5a, and 6a show the percentage area meeting the adverse hemodynamic criteria of low WSS (<0.5 Pa), and high WSSG (>200 Pa/m) at different times points in the cardiac cycle. Endothelial cells respond to shear stress26 and ideally cover the stent surface area within a few days after PCI.16 For this reason, the area considered is vessel and stent surface plus 5 mm of vessel on each side of the stent to capture any proximal or distal flow disturbances.Table 2

Bottom Line: Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG.For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts.In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand. s.beier@auckland.ac.nz.

ABSTRACT
Stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. The purpose of this study was to evaluate the impact of stent design on wall shear stress (WSS), time average WSS, and WSS gradient (WSSG), in idealized stent geometries using computational fluid dynamics. Strut spacing, thickness, luminal protrusion, and malapposition were systematically investigated and a comparison made between two commercially available stents (Omega and Biomatrix). Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG. Local hemodynamics worsened with luminal protrusion of the stent and with stent malapposition, adverse high WSS and WSSG were identified around peak flow and throughout the cardiac cycle respectively. For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts. In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

No MeSH data available.


Related in: MedlinePlus