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 . A medical device comprising: 
 a flexible metallic medical device formed of an implantable material, the flexible metallic medical device having deforming elements and non-deforming elements wherein the device is expandable from an insertion configuration to an expanded implanted configuration by deformation of the deforming elements; and    a plurality of holes formed in the non-deforming elements of the flexible metallic medical device, each of the holes containing a beneficial agent.    
   
   
       2 . The medical device of  claim 1 , wherein said beneficial agent is a drug.  
   
   
       3 . The medical device of  claim 1 , wherein said beneficial agent includes chemotherapy.  
   
   
       4 . The medical device of  claim 1 , wherein the plurality of holes are laser-drilled holes.  
   
   
       5 . The medical device of  claim 1 , wherein the nondeforming elements are struts.  
   
   
       6 . The medical device of  claim 5 , wherein the deforming elements are ductile hinges.  
   
   
       7 . The medical device of  claim 1 , wherein the flexible metallic medical device is formed in a substantially cylindrical tube.  
   
   
       8 . The medical device of  claim 1 , wherein the device is self expanding.  
   
   
       9 . The medical device of  claim 1 , wherein the device is balloon expandable.  
   
   
       10 . A method of delivering a beneficial agent to a patient comprising: 
 providing a flexible metallic medical device formed of an implantable material having deforming elements and non-deforming elements and having a beneficial agent disposed within a plurality of holes in the non-deforming elements;    inserting the medical device into a patient's body in a first insertion configuration; and    expanding the medical device at an implantation site within the patient's body to deliver the beneficial agent to the implantation site by deforming the deforming elements.    
   
   
       11 . The method of  claim 10 , wherein the beneficial agent delivered is a drug.  
   
   
       12 . The method of  claim 10 , wherein the beneficial agent delivered is a chemotherapy agent.  
   
   
       13 . The method of  claim 10 , wherein the non-deforming elements are struts.  
   
   
       14 . The method of  claim 13 , wherein the deforming elements are ductile hinges.  
   
   
       15 . The method of  claim 10 , wherein the medical device is self expanding.  
   
   
       16 . The method of  claim 10 , wherein the medical device is expanded with a balloon.  
   
   
       17 . A medical device comprising: 
 a substantially cylindrical medical device formed of an implantable material and expandable from an insertion configuration to an expanded implanted configuration, the substantially cylindrical device having first portions which function as strain concentration portions and second portions which have a lower strain than the first portions during expansion of the device from the insertion configuration to the implanted configuration; and    a plurality of holes formed in the second portions, the plurality of holes containing beneficial agent.    
   
   
       18 . The medical device of  claim 17 , wherein the first portions localize strain away from the plurality of holes containing beneficial agent.  
   
   
       19 . The medical device of  claim 17 , wherein said beneficial agent is a drug.  
   
   
       20 . The medical device of  claim 17 , wherein said beneficial agent includes chemotherapy.  
   
   
       21 . The medical device of  claim 17 , wherein the plurality of holes are laser-drilled holes.  
   
   
       22 . The medical device of  claim 17 , wherein the second portions are struts.  
   
   
       23 . The medical device of  claim 17 , wherein the first portions are ductile hinges.  
   
   
       24 . The medical device of  claim 17 , wherein the substantially cylindrical medical device is formed from a substantially cylindrical tube.  
   
   
       25 . The medical device of  claim 17 , wherein the device is self expanding.  
   
   
       26 . The medical device of  claim 17 , wherein the device is balloon expandable.  
   
   
       27 . A method of forming an expandable medical device for delivery of a beneficial agent, the method comprising: 
 forming a substantially cylindrical medical device comprising a plurality of struts interconnected by a plurality of strain concentrators wherein the device is expandable from an insertion configuration to an expanded implanted configuration by deformation of the strain concentrators;    forming a plurality of holes in the substantially cylindrical medical device struts; and    filling the plurality of holes with a beneficial agent containing a drug.    
   
   
       28 . The method of  claim 27 , wherein strain concentrators are ductile hinges.  
   
   
       29 . The method of  claim 27 , wherein the struts are essentially rigid beams.  
   
   
       30 . The method of  claim 27 , wherein the drug is a chemotherapy agent.