title: Intimal hyperplasia following implantation of helical-centreline and straight-centreline stents in common carotid arteries in healthy pigs: influence of intraluminal flow.
abstract: Intimal hyperplasia (IH) is a leading cause of obstruction of vascular interventions, including arterial stents, bypass grafts and arteriovenous grafts and fistulae. Proposals to account for arterial stent-associated IH include wall damage, low wall shear stress (WSS), disturbed flow and, although not widely recognized, wall hypoxia. The common non-planarity of arterial geometry and flow, led us to develop a bare-metal, nitinol, self-expanding stent with three-dimensional helical-centreline geometry. This was deployed in one common carotid artery of healthy pigs, with a straight-centreline, but otherwise identical (conventional) stent deployed contralaterally. Both stent types deformed the arteries, but the helical-centreline device additionally deformed them helically and caused swirling of intraluminal flow. At sacrifice, one month post stent deployment, histology revealed significantly less IH in the helical-centreline than straight-centreline stented vessels. Medial cross-sectional area was not significantly different in helical-centreline than straight-centreline stented vessels. By contrast, luminal cross-sectional area was significantly larger in helical-centreline than straight-centreline stented vessels. Mechanisms considered to account for those results include enhanced intraluminal WSS and enhanced intraluminal blood-vessel wall mass transport, including of oxygen, in the helical-centreline stented vessels. Consistent with the latter proposal, adventitial microvessel density was lower in the helical-centreline stented than straight-centreline stented vessels.
authors.affiliation: Department of Bioengineering, Imperial College London, , South Kensington Campus, Royal School of Mines Building, London SW7 2AZ, UK.
authors.forename: Colin Gerald
authors.initials: CG
authors.lastname: Caro
authors.forename: Anusha
authors.initials: A
authors.lastname: Seneviratne
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Heraty
authors.forename: Claudia
authors.initials: C
authors.lastname: Monaco
authors.forename: Martin G
authors.initials: MG
authors.lastname: Burke
authors.forename: Rob
authors.initials: R
authors.lastname: Krams
authors.forename: Carlos C
authors.initials: CC
authors.lastname: Chang
authors.forename: Paul
authors.initials: P
authors.lastname: Gilson
authors.forename: Gianfilippo
authors.initials: G
authors.lastname: Coppola
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000473:pathology* / Q000601:surgery; D006965:Hyperplasia / Q000473:pathology; D008955:Models, Cardiovascular; D015607:Stents / Q000009:adverse effects*; D034421:Sus scrofa; D017539:Tunica Intima / Q000473:pathology
keywords: blood–wall oxygen transport; helical-centreline arterial stent; intimal hyperplasia; swirling intraluminal blood flow; vessel wall hypoxia; wall shear stress