Variable stiffness stent
First Claim
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1. A stent having a circumference and an axis, comprising:
- a pattern of interconnected elements forming a plurality of rings made of a non-biodegrading material wherein rings comprise struts, rings are connected to adjacent rings by links and each ring extends about the circumference in an undulating pattern of alternating peaks and valleys; and
at least one of the peaks and valleys comprising;
an outer crest of a peak and an outer trough of a valley, wherein a distance between the outer crest and the outer trough is a width of the ring,a first strut extending from the outer crest to the outer trough of a first adjacent valley and a second strut extending from the outer crest to the outer trough of a second adjacent valley,a redundant crest integral to the peak, located between the outer crest and the outer trough of the first adjacent valley and extending between the first and second struts,the redundant crest including a notch,a first radial stiffness when the notch is severed, anda second radial stiffness, higher than the first radial stiffness, when the notch has not severed,wherein the peak is configured such that the outer crest is capable of carrying radial loads between the first and second struts after the redundant crest substantially fails.
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Abstract
A stent has one or more redundant crests for a ring. The redundant crest is located at a Y-crown for a peak-to-valley type stent pattern in one example. The stent may also have frangible bridges for connecting links. The stent'"'"'s radial stiffness decreases when a redundant crest fractures and its axial and bending stiffness decreases when a frangible bridge breaks.
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Citations
21 Claims
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1. A stent having a circumference and an axis, comprising:
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a pattern of interconnected elements forming a plurality of rings made of a non-biodegrading material wherein rings comprise struts, rings are connected to adjacent rings by links and each ring extends about the circumference in an undulating pattern of alternating peaks and valleys; and at least one of the peaks and valleys comprising; an outer crest of a peak and an outer trough of a valley, wherein a distance between the outer crest and the outer trough is a width of the ring, a first strut extending from the outer crest to the outer trough of a first adjacent valley and a second strut extending from the outer crest to the outer trough of a second adjacent valley, a redundant crest integral to the peak, located between the outer crest and the outer trough of the first adjacent valley and extending between the first and second struts, the redundant crest including a notch, a first radial stiffness when the notch is severed, and a second radial stiffness, higher than the first radial stiffness, when the notch has not severed, wherein the peak is configured such that the outer crest is capable of carrying radial loads between the first and second struts after the redundant crest substantially fails. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A stent, comprising:
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a pattern of interconnected elements forming a plurality of rings made of a nonbiodegrading material wherein rings comprise struts, rings are connected to adjacent rings by links and each ring extends about the circumference in an undulating pattern of alternating peaks and valleys; at least one of the rings comprising a variable stiffness ring wherein the variable stiffness ring comprises; an outer crest and an outer trough of a valley, wherein a distance between the outer crest and the outer trough is a width of the ring, a first strut extending from the outer crest to the outer trough of a first adjacent valley and a second strut extending from the outer crest to the outer trough of a second adjacent valley, a redundant crest integral to the peak, located between the outer crest and the outer trough of the first adjacent valley and, the redundant crest extending between the first and second struts, and the redundant crest including a notch, wherein surfaces of the redundant crest, outer crest and opposed portions of the first and second struts circumscribe a closed space; wherein a radial stiffness of the peak is proportional to a bar arm length between a load-bearing valley crest and a load-bearing peak crest, so that the variable stiffness ring has a first stiffness when the redundant crest is severed at the notch, and a second stiffness when the redundant crest has not severed at the notch, the second stiffness being higher than the first stiffness, and wherein the peak is configured such that the outer crest is capable of carrying radial loads between the first and second struts after the redundant crest substantially fails. - View Dependent Claims (20, 21)
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Specification