Expandable medical device with beneficial agent delivery mechanism

Abstract

An expandable tissue supporting device of the present invention employs ductile hinges at selected points in the expandable device. When expansion forces are applied to the device as a whole, the ductile hinges concentrate expansion stresses and strains in-small well defined areas. The expandable medical device including ductile hinges provides the advantages of low expansion force requirements, relatively thick walls which are radio-opaque, improved crimping properties, high crush strength, reduced elastic recoil after implantation, and control of strain to a desired level. The expandable tissue supporting device includes a plurality of elongated beams arranged in a cylindrical device and connected together by a plurality of ductile hinges. Although many ductile hinge configurations are possible, the ductile hinges preferably have a substantially constant hinge cross sectional area which is smaller than a beam cross sectional area such that as the device is expanded from a first diameter to a second diameter, the ductile hinges experience plastic deformation while the beams are not plastically deformed.

1 . An expandable medical device comprising:
 a plurality of beams, the plurality of beams joined together to form a substantially cylindrical device which is expandable from a cylinder having a first diameter to a cylinder having a second diameter, wherein the plurality of beams are undeformed during expansion from the first diameter to the second diameter;   a plurality of ductile hinges connecting the plurality of beams together in the substantially cylindrical device, wherein the ductile hinges have a smaller cross sectional area than the beams; and   a plurality of holes formed in the beams for containing a beneficial agent.   
   
   
       2 . The expandable medical device according to  claim 1 , further comprising a beneficial agent disposed within the plurality of holes. 
   
   
       3 . The expandable medical device according to  claim 2 , wherein said beneficial agent is a drug. 
   
   
       4 . The expandable medical device according to  claim 2 , wherein said beneficial agent includes chemotherapy. 
   
   
       5 . The expandable medical device according to  claim 1 , wherein the beams have a thickness of at least 0.005 inch. 
   
   
       6 . The expandable medical device according to  claim 1 , wherein the plurality of holes are laser drilled holes. 
   
   
       7 . An expandable medical device comprising:
 a cylindrical tube; and   a plurality of axial slots formed in the cylindrical tube in a staggered arrangement to define a network of elongated struts, the cylindrical tube being expandable or compressible from a first diameter to a second diameter;   a plurality of ductile hinges formed between the elongated struts, the ductile hinges allowing the cylindrical tube to be expanded or compressed from the first diameter to the second diameter by deformation of the ductile hinges, wherein the ductile hinges have a smaller cross sectional area than the struts; and   plurality of holes in the elongated struts for containing a beneficial agent.   
   
   
       8 . The expandable medical device according to  claim 7 , further comprising a beneficial agent disposed within the plurality of holes. 
   
   
       9 . The expandable medical device according to  claim 8 , wherein said beneficial agent is a drug. 
   
   
       10 . The expandable medical device according to  claim 8 , wherein said beneficial agent includes chemotherapy. 
   
   
       11 . The expandable medical device according to  claim 7 , wherein the plurality of holes are laser drilled holes. 
   
   
       12 . The expandable medical device according to  claim 7 , wherein the elongated struts have a thickness of at least 0.005 inch. 
   
   
       13 . An expandable medical device comprising:
 a plurality of beams, the plurality of beams joined together to form a substantially cylindrical device which is expandable from a cylinder having a first diameter to a cylinder having a second diameter, the plurality of beams each having a beam width in a circumferential direction;   a plurality of ductile hinges connecting the plurality of beams together in the substantially cylindrical device, the ductile hinges having a substantially constant width in a circumferential direction along a portion of a hinge length which is at least ⅓ a total hinge length, wherein the hinge width is smaller than the beam width such that as the device is expanded from the first diameter to the second diameter the ductile hinges experience plastic deformation while the beams are not plastically deformed; and   a plurality of holes in the beams for containing a beneficial agent.   
   
   
       14 . The expandable medical device according to  claim 13 , further comprising a beneficial agent disposed within the plurality of holes. 
   
   
       15 . The expandable medical device according to  claim 14 , wherein said beneficial agent is a drug. 
   
   
       16 . The expandable medical device according to  claim 14 , wherein said beneficial agent includes chemotherapy. 
   
   
       17 . The expandable medical device according to  claim 13 , wherein the beams have a thickness of at least 0.005 inch. 
   
   
       18 . The expandable medical device according to  claim 13 , wherein the plurality of holes are laser drilled holes.