Stent for treating vulnerable plaque

Abstract

An intravascular stent assembly for implantation in a body lumen, such as a coronary artery, is designed to treat a lesion with vulnerable plaque by reducing the fibrous cap stresses. The stent includes distal, proximal, and center sections where the center section is configured to treat the vulnerable plaque. The stent consists of radially expandable cylindrical rings generally aligned on a common longitudinal stent axis and either directly connected or interconnected by one or more interconnecting links placed so that the stent is flexible in the longitudinal direction while providing high degrees of radial strength and vessel scaffolding.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to vascular repair devices, and in particular to intravascular stents, which are adapted to be implanted into a patient's body lumen, such as a blood vessel or coronary artery, for the treatment of unstable or vulnerable, human atherosclerotic plaque. [0002] Currently, the treatment of unstable or vulnerable plaque presents a significant therapeutic challenge to medical investigators. Vulnerable plaque is characterized by a basic lesion which is a raised plaque beneath the innermost arterial layer, the intima. Atherosclerotic plaques are primarily composed of varying amounts of long chain extracellular matrix (ECM) proteins that are synthesized by smooth muscle cells. The other primary lesion component of atherosclerotic plaque includes lipoproteins, existing both extracellularly and within foam cells derived primarily from lipid-laden macrophages. In a more advanced lesion, a necrotic core may develop, consisting of l...

AI Technical Summary

Benefits of technology

The stent assembly effectively reduces cap stresses in vulnerable plaques, preventing rupture and maintaining vessel patency by distributing stress evenly and promoting neointimal thickening, thereby reducing the risk of thrombotic occlusion.

Problems solved by technology

Currently, the treatment of unstable or vulnerable plaque presents a significant therapeutic challenge to medical investigators.

With the rupture of fibroatheroma forms of vulnerable plaque, the luminal blood becomes exposed to tissue factor, a highly thrombogenic core material, which can result in total thrombotic occlusion of the artery.

In the erosive form of vulnerable plaque, mechanisms of thrombosis are less understood but may still yield total thrombotic occlusion.

Although rupture of the fibrous cap in a fibroatheroma is a major cause of myocardial infarction (MI) related deaths, there are currently no therapeutic strategies in place to treat lesions that could lead to acute MI.

Studies have shown that placement of the intravascular stent at a lesion site can induce neointimal thickening.

One of the difficulties encountered using prior art stents involved maintaining the radial rigidity needed to hold open a body lumen while at the same time maintaining the longitudinal flexibility of the stent to facilitate its delivery.

While other numerous prior art stents have had sufficient radial strength to hold open and maintain the patency of a coronary artery, they have lacked the flexibility required to easily navigate tortuous vessels without damaging the vessels during delivery.

A disadvantage may be that the metallic stent lacks flexibility which is important during the delivery of the stent to the target site.

With respect to polymer stents, they may have a tendency to be quite flexible and are advantageous for use during delivery through tortuous vessels, however, such polymer stents may lack the radial strength necessary to adequately support the lumen once implanted into an occlusive fibromuscular lesion of 70% stenosis or greater.

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