Medical device having coupled segments

Abstract

A scaffold is formed by several segments joined or connected to each other by only at least one coupling. The coupling decouples the segments in the axial direction over a finite distance of axial displacement. The scaffold when implanted in a peripheral vessel reduces loading on rings of a segment due to the decoupling of the segments in the axial direction over the finite distance.

1 - 20 . (canceled) 
     
     
         21 . A medical device, comprising:
 a first stent or scaffold segment and a second stent or scaffold segment, the first segment and the second segment having a pattern of adjoined rings, comprising:
 a first ring, a second ring, a third ring and a fourth ring, each ring forming peak and valley undulations, wherein 
 a peak of the first ring is adjoined with a valley of the second ring, 
 a peak of the third ring is adjoined with a valley of the fourth ring, 
 the adjoined rings form a plurality diamond shape cells, and 
 the first ring and fourth ring are end rings; and 
   a mechanical connection comprising at least one coupling having a lost motion distance (LMD) and a maximum axial distance (Z 1 );   wherein the first segment and the second segment are joined to each other by only the coupling.   
     
     
         22 . The medical device of  claim 21 , wherein each of the first and second segments are made from a polymer comprising poly(L-lactide). 
     
     
         23 . The medical device of  claim 21 , wherein each of the first and second segments are self-expanding segments made from a metal. 
     
     
         24 . The medical device of  claim 21 , wherein the coupling extends from a valley of the first segment's fourth ring to a peak of the second segment's first ring. 
     
     
         25 . The scaffold of  claim 21 , wherein the diamond shape cells have circumferentially aligned vertices. 
     
     
         26 . The scaffold of  claim 21 , wherein the coupling is a male-female coupling, a pin and socket coupling, a flexible band coupling, or a stiff band coupling. 
     
     
         27 . The scaffold of  claim 21 , wherein the LMD accounts for displacement of the first segment relative to the second segment, such that when implanted in a vessel the LMD is equal to about ½ D (TAN(Φ)), where D is an outer, expanded diameter of the first segment and Φ is between 10 and 30 degrees. 
     
     
         28 . The scaffold of  claim 21 , wherein the LMD or Z 1  is equal to about 7% to about 10% of a length of the first segment to account for an expected 7% to about 10% axial compression of the first segment when the first segment is implanted in a vessel. 
     
     
         29 . The medical device of  claim 21 , wherein Z 1  is equal to at least ½ a width of a diamond shape. 
     
     
         30 . The medical device of  claim 21 , wherein the coupling is a beam, string or thread; and wherein when the coupling is a thread or string, the string or thread joins together one pair of adjacent peaks of the first and second segments, or a plurality of pairs of adjacent peaks of the first and second segments. 
     
     
         31 . The medical device of  claim 21 , wherein the coupling comprises a first portion integrally formed with the first segment, a second portion integrally formed with the second segment, and a connection formed between the first and second portion and defining the LMD. 
     
     
         32 . The medical device of  claim 21 , further comprising a balloon catheter having a balloon, the first segment and second segments are crimped to the balloon, and the coupling is configured such that the first segment and the second segment are separated by a distance Z 2  to account for a shortening of a length of the segments when the segments are expanded by the balloon. 
     
     
         33 . A medical device, comprising:
 a stent segment, comprising:
 a first ring, a second ring, a third ring, and a fourth ring, 
 a peak of the first ring is adjoined with a valley of the second ring, 
 a peak of the third ring is adjoined with a valley of the fourth ring, 
 the first ring is an end ring forming peak and valley undulations, 
 the fourth ring is an end ring forming peak and valley undulations, and 
 a male portion of a male-female connector, the male portion being formed integrally with the fourth ring and extending from a peak of the fourth ring. 
   
     
     
         34 . The medical device of  claim 33 , wherein the stent segment has one, and only one male portion. 
     
     
         35 . The medical device of  claim 33 , wherein the stent segment is a self-expanding stent segment made from a metal. 
     
     
         36 . The medical device of  claim 33 , wherein the male portion forms a bulbous head configured for being received within a complementary shaped female portion of the male-female connector. 
     
     
         37 . The medical device of  claim 33 , wherein the first ring, the second ring, the third ring, and the fourth ring form a plurality of diamond shape cells. 
     
     
         38 . The medical device of  claim 33 , wherein the peak and valley undulations of the fourth ring are offset circumferentially from the peak and valley undulations of the first ring, such that a peak of the fourth ring is longitudinally aligned with a valley of the first ring. 
     
     
         39 . The medical device of  claim 33 , wherein the stent segment is a first stent segment, further comprising:
 the first stent segment, a second stent segment and a third stent segment mounted to a catheter and contained within a sheath,   wherein the second and third stent segments each comprise:
 a first ring, a second ring, a third ring, and a fourth ring, 
 a peak of the first ring is adjoined with a valley of the second ring, 
 a peak of the third ring is adjoined with a valley of the fourth ring, 
 the first ring is an end ring forming peak and valley undulations, 
 the fourth ring is an end ring forming peak and valley undulations, and 
 a male portion of a male-female connector integral with the fourth ring and extending from a peak of the fourth ring; 
   wherein each of the first, second and third segments are self-expanding; and   wherein each of the first, second and third segments are axially decoupled from each other when the sheath is withdrawn and the segments thereby self-expand, such that the first segment, second segment and third segment can be located at different axial locations relative to each other at an implant site   
     
     
         40 . The medical device of  claim 39 , wherein the first segment and the second segment are coupled to each other by the first segment's male portion and the second segment's male portion engaging with respective first and second female portions of the male-female connectors.