Longitudinally flexible stent

Abstract

An intravascular stent especially suited for implanting in curved arterial portions. The stent retains longitudinal flexibility after expansion. The stent is formed of intertwined meander patterns forming triangular cells. The triangular cells are adapted to provide radial support, and also to provide longitudinal flexibility after expansion. The triangular cells provide increased coverage of a vessel wall. The stent can have different portions adapted to optimize radial support or to optimize longitudinal flexibility. Loops in the stent are disposed and adapted to cooperate so that after expansion of said stent within a curved lumen, the stent is curved and cells on the outside of the curve open in length, but narrow in width whereas cells on the inside of the curve shorten in length but thicken in width to maintain a density of stent element area which much more constant than otherwise between the inside and the outside of the curve. As a result, when the stent is coated with a medicine the more constant density of stent elements results in an even dose being applied to the inside wall of the lumen, avoiding the possibility that a toxic dose be supplied at one area while a less than effective dose is applied to another area.

1 - 41 . (canceled) 
   
   
       42 . A stent having a longitudinal axis along the length of the stent comprising:
 a. a first loop containing section consisting of a single, continuous, generally sinusoidal pattern of loops around the entire circumference of the stent, said first loop containing section having an axis orthogonal to the longitudinal axis of the stent, the loops in said first loop containing section occurring at a first frequency;   b. a second loop containing section consisting of a single, continuous, generally sinusoidal pattern of loops around the entire circumference of the stent, said second loop containing section having an axis orthogonal to the longitudinal axis of the stent, the loops in said second loop containing section also occurring at said first frequency;   c. said first and second loop containing sections alternating for at least two consecutive repetitions along the longitudinal axis of the stent; and   d. a third loop containing section consisting of a single, continuous, generally sinusoidal pattern, said third loop containing section having an axis orthogonal to the longitudinal axis of the stent, the loops in said third loop containing section occurring at a second frequency that is higher than said first frequency, said third loop containing section disposed in the general circumferential space between each adjacent first and second loop containing sections, said third loop containing sections joining to said first and second loop containing sections directly without any intervening material to form a uniform pattern of flexible cells; and   e. the loops of the first, second, and third loop containing sections further include struts having a thickness in the radial direction and width in the circumferential direction, wherein the struts of the first and second loop containing sections are wider than the width of the struts of the third loop containing section.   
   
   
       43 . The stent according to  claim 42 , wherein said stent is coated with a medicine. 
   
   
       44 . The stent according to  claim 42 , wherein the first, second and third loop containing sections are disposed and adapted to cooperate so that, when the expanded stent is in a curved lumen, cells on the outside of the curve open in length but narrow circumferentially, whereas cells on the inside of the curve shorten in length but widen circumferentially. 
   
   
       45 . A stent consisting essentially of a plurality of triangular cells, each triangular cell consisting essentially of three loop containing sections:
 a. a first loop containing section, the first loop containing section having loops, said loops occurring at a first frequency, said loop containing section having a first end and a second end;   b. a second loop containing section having loops, said loops occurring at said first frequency, said second loop containing section having a first end and a second end; and   c. a third loop containing section having loops, said loops occurring at a second frequency lower than the first frequency, said third loop containing section having a first end and a second end;   d. wherein the first end of the first loop containing section is joined to the second end of the second loop containing section, the first end of the second loop containing section is joined to the second end of the third loop containing section, and the first end of the third loop containing section is joined to the second end of the first loop containing section;   e. wherein the first, second and third loop containing sections further include struts having a thickness in the radial direction and width in the circumferential direction, wherein the struts of the third loop containing section are wider than the width of the struts of the first and second loop containing sections.   
   
   
       46 . The stent according to  claim 45 , wherein said stent is coated with a medicine. 
   
   
       47 . An expandable coronary stent consisting essentially of a pattern of uniform cells, each of the cells consisting essentially of a plurality of substantially straight members consisting of:
 a. a first member having a first end and a second end;   b. a second member having a first end and a second end;   c. a third member having a first end and a second end;   d. a fourth member having a first end and a second end; the first end of the first member communicating with the first end of the second member, the second end of the second member communicating with the second end of the third member, and the first end of the third member communicating with the first end of the fourth member;   e. the first member and the second member with the curved portion at their first ends forming a first loop;   f. the third member and the fourth member with the curved portion at their first ends forming a second loop, the first, second, third and fourth members forming a portion of a first circumferential band formed of a single, continuous, generally sinusoidal pattern of loops;   g. a fifth member having a first end and a second end;   h. a sixth member having a first end and a second end;   i. a seventh member having a first end and a second end;   j. an eighth member having a first end and a second end;   k. a ninth member having a first end and a second end; and   l. a tenth member having a first end and a second end, the first end of the fifth member communicating with the second end of the first member, the second end of the fifth member communicating with the second end of the sixth member, the first end of the sixth member communicating with the first end of the seventh member, the second end of the seventh member communicating with the second end of the eighth member, the first end of the eighth member communicating with the first end of the ninth member, the second end of the ninth member communicating with the second end of the tenth member, and the first end of the tenth member communicating with the second end of the fourth member;   m. the fifth member and the sixth member with the curved portion at their ends forming a third loop;   n. the seventh member and the eighth member with the curved portion at their ends forming a fourth loop; and   o. the ninth member and the tenth member with the curved portion at their ends forming a fifth loop, said fifth, sixth, seventh, eighth, ninth and tenth members forming a portion of a second circumferential band formed of a single, continuous, generally sinusoidal pattern of loops disposed in the general circumferential space between each of the first circumferential bands to form a pattern that repeats at least two consecutive repetitions along the longitudinal axis of the stent, wherein each first and each second circumferential band is a single, continuous generally sinusoidal pattern extending in the circumferential direction and the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth members form a uniform pattern of flexible cells; and   p. the first, second, third and fourth members having a thickness in the radial direction and width in the circumferential direction, wherein the first, second, third and fourth members are wider than the width of the fifth, sixth, seventh, eighth, ninth and tenth members.   
   
   
       48 . The stent according to  claim 47 , wherein said stent is coated with a medicine. 
   
   
       49 . A coronary stent having a longitudinal axis along the length of the stent consisting essentially of in both the unexpanded and expanded state:
 a. a first loop containing section, said first loop containing section having an axis perpendicular to the longitudinal axis of the stent, the loops in said first loop containing section occurring at a first frequency;   b. a second loop containing section, said second loop containing section having an axis perpendicular to the longitudinal axis of the stent, the loops in said second loop containing section also occurring at said first frequency, said second loop containing section being 180° out of phase with said first loop containing section along the longitudinal axis of the stent;   c. at least one of said first and second loop containing sections consisting of a single, continuous, generally sinusoidal pattern; and   d. a third loop containing section, said third loop containing section formed of a single, continuous, generally sinusoidal pattern extending in a continuous band of loops around the entire circumference of the stent, the loops in said third loop containing section occurring at a second frequency that is higher than said first frequency, said loops in said third loop containing section having an axis parallel to the axis of the first and second loop containing sections, said third loop containing section disposed in the general circumferential space between each of said first and second loop containing sections to form consecutively repeating patterns along the longitudinal axis of the stent for at least two repetitions, said first, second and third loop containing sections connected at junction points to form a pattern of uniform cells; and   e. the loops of the first, second, and third loop containing sections further include struts having a thickness in the radial direction and width in the circumferential direction, wherein the struts of the first and second loop containing sections are wider than the struts of the third loop containing section.   
   
   
       50 . The stent according to  claim 49 , wherein said stent is coated with a medicine.