Stent apparatus and treatment methods
Inventors
Caro, Colin Gerald • Burke, Martin G. • Gilson, Paul • Heraty, Kevin B. • Yeo, Nicholas
Assignees
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Publication Number
US-9907679-B2
Publication Date
2018-03-06
Expiration Date
Abstract
An apparatus including a plurality of stents is provided, each stent having a center line curving in three dimensions. The plurality of stents includes at least one stent with a center line having a right handed curvature and at least one stent with a center line having a left handed curvature.
Core Innovation
A conventional straight stent disposed in a blood vessel can induce local tissue hypoxia, which promotes angiogenesis and atherosclerotic progression. The document describes that the hypoxia/angiogenic stimuli can involve HIF/VEGF signalling and the presence of adventitial microvessels, and presents this relationship as a problem underlying stent-related progression, including intimal hyperplasia and restenosis.
To address this, the invention provides stent treatment in which an expandable member reshapes an already-disposed stent so that the stent adopts a three-dimensionally curving centre line. Expanding the expandable member from a collapsed condition to an expanded condition produces a centre line which curves in three dimensions and causes the stent to adopt a corresponding three-dimensionally curving centre line. The document describes configurations where the centre line curves as a helical geometry, including right-handed and left-handed curvature.
The document further extends to drug eluting 3D-helical stents placed in a main vessel with a branch vessel extending from the main vessel. By positioning at least a portion of the stent upstream of the branch vessel, the document describes secondary flow and improved drug transport to the struts, and potentially to downstream branch/collateral vessels. The document also describes selecting stent handedness based on natural swirl flow, and reports in vivo comparison results in pigs showing reduced intimal thickness/intima-media ratio and reduced adventitial microvessel density with helical stents.
Claims Coverage
The document contains two independent claims, each focused on a main inventive aspect: reshaping an already-disposed stent to treat hypoxia by introducing a three-dimensionally curving centre line via an expandable member, and using a drug eluting, three-dimensionally curved stent in a main vessel with upstream positioning relative to a branch vessel.
Reshaping a disposed stent to treat hypoxia via a 3D-curved centre line
A method of treating hypoxia in tissue of a blood vessel in which a stent is already disposed by placing an expandable member in a collapsed condition radially inwardly of the stent, and expanding the expandable member to an expanded condition in which the expandable member has a centre line which curves in three dimensions so as to cause the stent to adopt a shape with a centre line which also curves in three dimensions.
Drug eluting 3D-curved stent placed in a main vessel upstream of a branch
A method of treating a subject for whom blood vessel stenting is indicated by placing a drug eluting stent in the vessel, where the stent has a centre line which curves in three dimensions, the vessel is a main vessel and a branch vessel extends from the main vessel, and the stent is placed in the main vessel so that at least a portion of the stent extends in the main vessel upstream of the branch vessel.
Across the independent claims, the inventive coverage centers on introducing a three-dimensionally curving centre line, including helical configurations, to reshape stent geometry, either to treat hypoxia after stent placement or to guide drug delivery by upstream placement of a drug eluting 3D-curved stent in relation to a branch vessel.
Stated Advantages
Improved intraluminal mixing with reduced boundary-layer thickness.
Enhanced blood-to-wall oxygen mass transport and reduced hypoxia/angiogenic stimuli.
Lower intimal hyperplasia.
Potentially improved drug transport to struts and downstream branch/collateral vessels.
Documented Applications
Treating hypoxia in tissue of a blood vessel where a stent is already disposed.
Treating a subject for whom blood vessel stenting is indicated by placing a drug eluting stent in a main vessel with a branch vessel, including positioning upstream of the branch vessel.
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