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-10531970-B2
Publication Date
2020-01-14
Expiration Date
Abstract
There is disclosed a method of treating hypoxia in tissue of a blood vessel, the method comprising placing a stent in the vessel, the stent having a centre line which curves in three dimensions to promote the supply of oxygen from the blood flowing in the lumen of the stented vessel to the vessel wall. There is disclosed a method of treating a subject with diabetic atherosclerosis, the method comprising placing a stent in a blood vessel of the subject, the stent having a centre line which curves in three dimensions to promote the supply of oxygen from the blood flowing in the lumen of the stented vessel to the vessel wall.
Core Innovation
The invention relates to treating hypoxia in tissue of a blood vessel by placing a stent in a collapsed condition and expanding the stent to an expanded condition in which the stent has a centre line that curves in three dimensions. The expanded stent is configured to cause the vessel to adopt a shape in which it also has a centre line that curves in three dimensions. The stent comprises a shape memory material.
The approach is framed as increasing intraluminal mixing and swirling flow by using a three-dimensionally curved centre line, including a helical centre line. This is described as reducing a boundary-layer thickness and enhancing blood-to-wall oxygen mass transport, thereby reducing vessel wall hypoxia.
The document also contrasts the three-dimensionally curved centre line stent with conventional straight and drug eluting stents, and provides a mechanistic rationale linking vessel hypoxia to adventitial micro-vessel density and angiogenesis. It describes an ex vivo and in vivo study in porcine carotid arteries comparing straight versus helical stents.
Claims Coverage
The independent claim covers a hypoxia treatment method using a collapsed-to-expanded stent with a three-dimensional-curved centre line that makes the vessel adopt a corresponding three-dimensional-curved shape, where the stent comprises a shape memory material. The claim set adds six inventive features refining the geometry, comparison conditions, and expansion mechanism.
Hypoxia treating stent with three-dimensional curved centre line
A method of treating hypoxia in tissue of a blood vessel by placing a stent in a collapsed condition in the vessel and expanding the stent to an expanded condition in which the stent has a centre line which curves in three dimensions so as to cause the vessel to adopt a shape in which it also has a centre line which curves in three dimensions.
Shape memory material stent
The method wherein the stent comprises a shape memory material.
Three-dimensional curved centre line in the expanded state
The method wherein, when the stent is expanded, it has an expanded centre line which curves in three dimensions.
Reduced three-dimensional curvature in-vessel versus ex vivo
The method wherein, when a stent is expanded in a vessel, the stent has reduced three-dimensional curvature compared with the three-dimensional curvature when the stent is expanded ex vivo.
Helical centre line in the expanded state
The method wherein, when the stent is expanded ex vivo, it has a helical centre line.
Helical amplitude and/or pitch comparison in-vessel versus ex vivo
The method wherein, when the stent is expanded in a vessel, it exhibits reduced helical amplitude and/or increased pitch compared with the stent’s helical amplitude and/or pitch when expanded ex vivo.
Expansion by removing an external radial constraint
The method wherein the stent is expanded from the collapsed condition to the expanded condition by removing an external radial constraint from the stent.
Overall, claim coverage centers on expanding a shape-memory stent from a collapsed condition to an expanded condition that induces a three-dimensionally curved vessel centre line, with further refinements specifying three-dimensional and helical geometry, comparative curvature, amplitude, and pitch relationships, and expansion by removal of an external radial constraint.
Stated Advantages
Reduces vessel wall hypoxia by enhancing blood-to-wall oxygen mass transport.
Reduces angiogenic signaling.
Reduces intimal hyperplasia and restenosis.
Reduces boundary-layer thickness via increased intraluminal mixing and swirling flow.
Reduces intimal thickness and intima/media thickness ratio in porcine carotid comparisons with straight stents.
Reduces adventitial micro-vessel density in porcine carotid comparisons with straight stents.
Documented Applications
Treating vessel wall hypoxia in tissue of a blood vessel, including in diabetic atherosclerosis, using stents having a three-dimensionally curved centre line, including helical.
Comparative evaluation of straight versus helical stents in porcine carotid arteries, reporting reduced intimal thickness, reduced intima/media thickness ratio, and reduced adventitial micro-vessel density for helical stents.
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