Implantable and lumen-supporting stents and related methods of manufacture and use

Abstract

An implantable stent includes multiple circumferential segments that surround a bore and are connected in series along a length to form a tubular wall. Multiple adjacent alternating opposite facing crowns arranged along each segment's circumference are bridged by struts. The struts include a series of staggered arcuate edges with limited flats to provide a limited region of maximum width between significantly extended reducing diameter tapers at either end where they transition into the crowns. Connections between adjacent segments are wider and stiffer than the struts and strut-crown transitions in the segments. The crowns include inner and outer radii with off-set centers along a common axis to provide medial crown peaks along the axis that are wider than the narrowed crown shoulders on either side of the axis and from which the tapered struts extend. Material strain and flexure along the stent during lateral bending is distributed mainly within the segments, e.g. along the struts or crowns, versus at the connections between segments. Material strain and deformation during radial expansion is principally concentrated at the crown shoulders and tapered transition region with the struts. Particular closed-open-closed arrangements along the stent length are disclosed, though with fewer stent connections in the relatively “closed” end-portions along the stent than are provided by other typically “open” cell stents in prior use. Enhanced combinations of performance characteristics are provided regarding visibility, trackability, expansion characteristics, fatigue failures, coating integrity, and local drug delivery from the stent.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Applications No. 60 / 981,433 filed Oct. 19, 2007 which is incorporated by reference herein in its entirety.FIELD OF THE INVENTION[0002]This invention relates to implantable medical devices. More specifically, the invention relates to implantable and lumen-supporting stents. Still more specifically, it relates to such stents for the treatment or inhibition of stenoses in coronary or peripheral vessels in humans.BACKGROUND OF THE INVENTION[0003]Cardiovascular disease, including atherosclerosis, is the leading cause of death in the United States. The medical community has developed a number of methods and devices for treating coronary heart disease, some of which are specifically designed to treat the complications resulting from atherosclerosis and other forms of coronary vessel narrowing.[0004]An important development for treating atherosclerosis a...

AI Technical Summary

Benefits of technology

[0014]One aspect of the present disclosure provides a stent system with an improved stent. According to one embodiment, the stent includes improved expansion characteristics. According to another embodiment, the stent includes improved lateral bending characteristics. In one particular embodiment, the stent undergoes lateral or radial deflection with strain distribution primarily at transition regions between struts and crown shoulders on opposite sides of crown peaks of the stent's filamental pattern. In another embodiment, the stent includes geometry along crown regions that differ from strut geometry, providing enhanced deflection characteristics in combination with enhanced characteristics along the strut, such as for example for drug delivery or visibility.

[0024]In another embodiment, the low strain region comprises at least one of (a) a width in a circumferential plane around the longitudinal axis that is substantially greater than a width of the high strain region along the longitudinal axis, (b) a width that is substantially greater than a radial thickness at the respective low strain region, and (c) a substantially increased radiopacity versus the high strain region.

[0028]Various additional modes, embodiments, features, and variations are also contemplated with respect to these various aspects and modes, providing still further benefit and utility.

Problems solved by technology

It is noted however to make clear, the estimated dimensions and specific material properties assigned to the modeled stents based upon these commercial stents likely do not match those actual stents with perfect accuracy.

Thus, this study, and results and conclusions made, relate only to “estimated models” considered to have certain “similarities” with these commercial stents, but do not directly represent those actual commercial stents or their manufacturers, nor capture or represent their actual characteristics or performance.

Conversely, if the width of the struts of that model #1 were uniform at the crown peaks with same increased width vs. radial thickness as along the struts, the expansion characteristics would likely be altered, such as for example: requiring higher inflation pressure to produce similar strain at the crowns necessary for expansion; potential for higher recoil; and possibly adverse consequences of twisting of the crowns out of plane when straining a planar structure of higher width than thickness in the circumferential plane.

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