Flexible stent and method of manufacture

Abstract

A preferred embodiment of a stent provides a folded strut section that provides both structural rigidity and reduction in foreshortening of the stent mechanism. A flexible section provides flexibility for delivery of the stent mechanism. In a second embodiment, flexible section columns are angled with respect to each other, and to the longitudinal axis of the stent. These relatively flexible sections are oppositely phased in order to negate any torsion along their length. In yet another embodiment, the flexible connector can take on an undulating shape (like an “N”), but such that the longitudinal axis of the connector is not parallel with the longitudinal axis of the stent. Finally, a new method is disclosed for making stents. The method consists of performing a standard photochemical machining process of cutting, cleaning and coating the tube with a photoresist. However, unlike former methods, the photoresist image is developed on the surface of the cylindrical metallic tube, which results in a controlled variable etching rate at selected sites on the cylindrical metallic tube during the etching process. Further embodiments provide living hinge connectors and connections along the length of the radial strut member.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority from Ser. No. 09 / 797,815 filed Mar. 2, 2001, now U.S. Pat. No.; which claims priority from Ser. No. 60 / 272,696, entitled “Flexible Stent and Method of Manufacture”, filed Mar. 1, 2001.BACKGROUND ART [0002] A stent is commonly used as a tubular structure left inside the lumen of a duct to relieve an obstruction. Commonly, stents are inserted into the lumen in a non-expanded form and are then expanded autonomously (or with the aid of a second device) in situ. A typical method of expansion occurs through the use of a catheter mounted angioplasty balloon, which is inflated within the stenosed vessel or body passageway, in order to shear and disrupt the obstructions associated with the wall components of the vessel and to obtain an enlarged lumen. [0003] In the absence of a stent, restenosis may occur as a result of elastic recoil of the stenotic lesion. Although a number of stent designs have been reported, ...

AI Technical Summary

Benefits of technology

The invention provides a stent that has little foreshortening (when the stent expands and contracts) and is more flexible during delivery. The stent has a flexible section and a folded strut section that opens upon expansion. The flexible section provides flexibility while the folded strut section provides structural rigidity. The stent has a unique design that reduces foreshortening and kinking (when the stent is expanded and interacts with the balloon). The stent also has a new method for manufacturing that allows for controlled variable etching rate and the ability to manufacture non-rectangular struts. Overall, the stent has improved flexibility and reduced foreshortening while maintaining structural rigidity.

Problems solved by technology

Although a number of stent designs have been reported, these designs have suffered from a number of limitations.

This design has at least one important disadvantage, for example, according to this design, protruding edges occur when the stent is flexed around a curve raising the possibility of inadvertent retention of the stent on plaque deposited on arterial walls.

This may cause the stent to form emboli or move out of position and further cause damage to the interior lining of healthy vessels.

Images