Post-implantation shear stress assessment: an emerging tool for differentiation of bioresorbable scaffolds

Abstract

Optical coherence tomography based computational flow dynamic (CFD) modeling provides detailed information about the local flow behavior in stented/scaffolded vessel segments. Our aim is to investigate the in-vivo effect of strut thickness and strut protrusion on endothelial wall shear stress (ESS) distribution in ArterioSorb Absorbable Drug-Eluting Scaffold (ArterioSorb) and Absorb everolimus-eluting Bioresorbable Vascular Scaffold (Absorb) devices that struts with similar morphology (quadratic structure) but different thickness. In three animals, six coronary arteries were treated with ArterioSorb. At different six animals, six coronary arteries were treated with Absorb. Following three-dimensional(3D) reconstruction of the coronary arteries, Newtonian steady flow simulation was performed and the ESS were estimated. Mixed effects models were used to compare ESS distribution in the two devices. There were 4591 struts in the analyzed 477 cross-sections in Absorb (strut thickness = 157 µm) and 3105 struts in 429 cross-sections in ArterioSorb (strut thickness = 95 µm) for the protrusion analysis. In cross-section level analysis, there was significant difference between the scaffolds in the protrusion distances. The protrusion was higher in Absorb (97% of the strut thickness) than in ArterioSorb (88% of the strut thickness). ESS was significantly higher in ArterioSorb (1.52 ± 0.34 Pa) than in Absorb (0.73 ± 2.19 Pa) (p = 0.001). Low- and very-low ESS data were seen more often in Absorb than in ArterioSorb. ArterioSorb is associated with a more favorable ESS distribution compared to the Absorb. These differences should be attributed to different strut thickness/strut protrusion that has significant effect on shear stress distribution.

The relationship between coronary stent strut thickness and the incidences of clinical outcomes after drug‐eluting stent implantation: A systematic review and meta‐regression analysis

“…Immediately after being exposed to coronary blood flow, thick struts promote the creation of the flow conditions behind struts that are favorable for thrombus formation, characterized by flow recirculation, low ESS, and prolonged particle residence time 4,15,24,25 . Thinner struts are buried into the vessel wall with less strut protrusion into coronary blood flow, reducing hemodynamic burden that is favorable for thrombus formation 26 . However, in later phase, more important factors for ST were reported as late remodeling and delayed neointimal coverage, which hinders the encapsulation of the strut protrusions 4,27 .…”

“…4,15,24,25 Thinner struts are buried into the vessel wall with less strut protrusion into coronary blood flow, reducing hemodynamic burden that is favorable for thrombus formation. 26 However, in later phase, more important factors for ST were reported as late remodeling and delayed neointimal coverage, which hinders the encapsulation of the strut protrusions. 4,27 The polymer in early DESs was associated with delayed neointimal coverage due to chronic inflammation, while a biocompatible polymer in new DES substantially reduced late inflammatory reactions.…”

Biomechanical Forces and Atherosclerosis: From Mechanism to Diagnosis and Treatment

“…In the vascular wall areas exposed to WSS less than 1 Pa, neointimal hyperplasia and thrombosis are developed significantly more often. Further study of changes associated with stent implantation may contribute to the development of new stents and grafts, as well as prognostic models that minimize the risks associated with stent restenosis [ 74 ].…”

Cardiovascular imaging 2019 in the International Journal of Cardiovascular Imaging

“…The BVS are still a hot topic in the research field and there were many publications in the journal this last year. Tenekecioglu et al [24] assessed the post-implantation shear stress as an emerging tool for differentiation of BVS. They investigated the in-vivo effect of strut thickness and strut protrusion on endothelial wall shear stress (ESS) distribution in Arte-rioSorb® Absorbable Drug-Eluting Scaffold (ArterioSorb) and Absorb everolimus-eluting Bioresorbable Vascular Scaffold (Absorb®, Abbott Vascular); devices with similar morphology (quadratic structure) but different thickness, including 4591 struts in the analyzed 477 cross-sections in Absorb® (strut thickness = 157 µm) and 3105 struts in 429 cross-sections in ArterioSorb® (strut thickness = 95 µm) for the protrusion analysis.…”