BACKGROUND

1. Field

The present invention relates generally techniques and structures for securing the ends of strands, such as wires, of devices suited for placement in anatomical structures, and the resulting devices. Examples of such devices include woven, self-expanding stents.

2. Description of Related Art

Examples of devices suitable for insertion into an anatomical structure that are created from one or more strands are found in U.S. Pat. Nos. 6,007,574; 6,419,694; and 7,018,401; and in U.S. Patent Application Publication Nos. US 2005/0049682 and US 2006/0116752, all of which are incorporated by reference.

SUMMARY OF THE INVENTION

Some embodiments of the present methods include securing a coupling structure to a first strand end portion of a device configured for insertion into an anatomical structure; and securing the coupling structure to a second strand end portion of the device; where the first and second strand end portions are substantially aligned, the coupling structure is not a strand of the device, and the device includes one or more strands that include nickel and titanium. In some embodiments, the length of the coupling structure is less than 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 percent of the length of the device; this may be true for each coupling structure that is used. The coupling structure may be configured such that it has a passageway before it is secured to the first and second strand portions, and it may be placed into direct contact with the first and second strand end portions prior to the securing. The device may be a stent (e.g., a stent woven from multiple strands), or any other medical device suited for use in treating a patient, such as a filter or an occluder. The device may be self-expanding. The device may have two or more device ends (such as the two ends of a straight stent or the three ends of a bifurcated stent), and each device end may be characterized by or defined by strand bends, where the strand bends of a given device end are similar (e.g., substantially similar) in shape to at least each other and in some instances to all of the strand bends of all the device ends, such that one device end looks very similar to the other device end or device ends. The number of coupling structures that are used may correspond to the number of strands (e.g., wires) that are used to create the device, and they may be positioned in axial alignment (parallel to the longitudinal axis of the device) or they may be axially offset from each other and positioned around the circumference of the device. The securing may be accomplished by welding (e.g., laser welding) the coupling structure to the first strand end portion to create a first welded region and by welding the coupling structure to the second strand end portion to create a second welded region. The two welded regions may be separated from each and unconnected by any other welded region. The two strand end portions directly touch each other in some embodiments, and in other embodiments are not in direct contact with each other. The strand end portions may be substantially aligned with each other (end-to-end), or they may be positioned in side-by-side relationship (which may be characterized as overlapping). In some embodiments, the coupling structure is a piece of material that is separate from the first strand end portion and from the second strand end portion and, when a weld is used to accomplish the securing, is placed into direct contact with both strand end portions before the welding begins. In some embodiments, some or all of the securing steps result in a given half of a given strand being secured to either (a) only one other strand or (b) only the other half of the same strand. In some embodiments, the coupling structure is positioned beneath a strand that crosses over it. In some embodiments, all coupling structures that are used are positioned in this same fashion. In some embodiments, neither the coupling structure nor the strand end portions to which it is secured undergo a smoothing step after the securing is complete. In some embodiments where the device is woven from multiple strands such that strand crossings are created defining obtuse angles that increase when the device is axially compressed from an unconstrained state, each device opening (other than the openings that border the longitudinal passageway or passageways of the device) is defined by at least three strand crossings, where each strand crossing is defined by two crossed strand portions. In some embodiments, the coupling structure positioned nearest to a particular end of the device (a “device end”) is spaced apart from all device ends (even at the portion of the coupling structure nearest the device end in question) by at least one strand crossing (in some embodiments, by at least two strand crossings; in some embodiments, by at least three strand crossings; in some embodiments, by at least four strand crossing; in some embodiments, by at least five strand crossings) in a direction (e.g., along a line) that is substantially parallel with a longitudinal axis of the device.

Some embodiments of the present methods include welding a coupling structure to a first strand end portion of a device configured for insertion into an anatomical structure; and welding the coupling structure to a second strand end portion of the device; where the coupling structure is not a strand of the device, and the device includes one or more strands that include nickel and titanium.

The present devices may have one or more strands and be configured for insertion into an anatomical structure. In some embodiments, the present devices include a coupling structure secured to two different strand end portions that are substantially aligned with each other; where the two different strand end portion includes nickel and titanium, and the coupling structure is not a strand of the device. In some embodiments, the present devices include a coupling structure welded to two different strand end portions; where the two different strand end portion includes nickel and titanium, and the coupling structure is not a strand of the device. The device may be a stent, or any other medical device suited for use in treating a patient, such as a filter or an occluder. The number of coupling structures that are used may correspond to the number of strands (e.g., wires) the device has, and they may be positioned in axial alignment (parallel to the longitudinal axis of the woven device) or they may be axially offset from each other and positioned around the circumference of the device. The strand end portions in each pair that are secured with (e.g., welded to) a given coupling structure may be substantially aligned with each other or they may be placed in side-by-side relationship with each other (which may be characterized as overlapping). In some embodiments, the length of the coupling structure is less than 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 percent of the length of the device; this may be true for each coupling structure that is used. The coupling structure may be configured such that it has a passageway before it is secured to the first and second strand portions, and it may be placed into direct contact with the first and second strand end portions prior to being secured (e.g., welded). The device may be a stent (e.g., a stent woven from multiple strands), or any other medical device suited for use in treating a patient, such as a filter or an occluder. The device may be self-expanding. The device may have two or more device ends (such as the two ends of a straight stent or the three ends of a bifurcated stent), and each device end may be characterized by or defined by strand bends, where the strand bends of a given device end are similar (e.g., substantially similar) in shape to at least each other and in some instances to all of the strand bends of all the device ends, such that one device end looks very similar to the other device end or device ends. The number of coupling structures that are used may correspond to the number of strands (e.g., wires) that are used to create the device, and they may be positioned in axial alignment (parallel to the longitudinal axis of the device) or they may be axially offset from each other and positioned around the circumference of the device. The coupling structure may be secured to the first strand end portion by a weld that forms a first welded region, the coupling structure is secured to the second strand end portion by a weld that forms a second welded region, and the first and second welded regions are not directly connected to each other by another welded region. The two welded regions may be separated from each and unconnected by any other welded region. The two strand end portions directly touch each other in some embodiments, and in other embodiments are not in direct contact with each other. In some embodiments, the coupling structure is a piece of material that is separate from the first strand end portion and from the second strand end portion and, when a weld is used to secure the coupling structure to those strand end portions, is placed into direct contact with both strand end portions before the welding begins. In some embodiments, a given half of a given strand of the device is secured to either (a) only one other strand or (b) only the other half of the same strand. In some embodiments, the coupling structure is positioned beneath a strand that crosses over it. In some embodiments, all coupling structures that are used are positioned in this same fashion. In some embodiments, neither the coupling structure nor the strand end portions to which it is secured require smoothing after being secured. In some embodiments where the device is woven from multiple strands such that strand crossings are created defining obtuse angles that increase when the device is axially compressed from an unconstrained state, each device opening (other than the openings that border the longitudinal passageway or passageways of the device) is defined by at least three strand crossings, where each strand crossing is defined by two crossed strand portions. In some embodiments, the coupling structure positioned nearest to a particular end of the device (a “device end”) is spaced apart from all device ends (even at the portion of the coupling structure nearest the device end in question) by at least one strand crossing (in some embodiments, by at least two strand crossings; in some embodiments, by at least three strand crossings; in some embodiments, by at least four strand crossing; in some embodiments, by at least five strand crossings) in a direction (e.g., along a line) that is substantially parallel with a longitudinal axis of the device.

Details associated with these embodiments and others are provided below.

