Balloon catheter devices with sheath covering

Abstract

Catheter devices having an expandable balloon for delivering a therapeutic agent to a body site. In one aspect, one or more sheaths are disposed around the balloon with the therapeutic agent being disposed within the sheath, being disposed over the sheath, being contained in the space between the sheath and the balloon, or being otherwise associated with the sheath. In another aspect, the balloon includes a micro-electromechanical system (MEMS) for drug delivery.

1 . A medical device comprising:
 a catheter;   a balloon mounted on the catheter;   a sheath disposed around the balloon, wherein the sheath has a plurality of weakened portions, wherein the weakened portions are arranged in a grid-like pattern or extend substantially radially along the sheath, and wherein the sheath is disrupted at one or more of the weakened portions when the balloon is expanded; and   a therapeutic agent disposed between the surface of the balloon and the sheath.   
     
     
         2 . The medical device of  claim 1 , wherein the weakened portions are perforation lines. 
     
     
         3 . The medical device of  claim 1 , wherein the weakened portions are arranged in a grid-like pattern. 
     
     
         4 . The medical device of  claim 3 , wherein the disruption of the sheath along the perforation lines creates fragments. 
     
     
         5 . The medical device of  claim 1 , wherein the weakened portions extend substantially radially along the sheath. 
     
     
         6 . The medical device of  claim 3 , wherein the size of at least some of the individual grid units are 100 μm or less. 
     
     
         7 . The medical device of  claim 4 , wherein at least some of the fragments have a size of 100 μm or less. 
     
     
         8 . The medical device of  claim 1 , wherein the weakened portions of the sheath are areas of the sheath that are attached to the balloon. 
     
     
         9 . The medical device of  claim 1 , wherein the weakened portions of the sheath have a different thickness or different composition that another portion of the sheath. 
     
     
         10 . The medical device of  claim 1 , wherein the therapeutic agent is provided as a patterned layer. 
     
     
         11 . The medical device of  claim 10 , wherein the patterned layer of therapeutic agent has ridges, and wherein the weakened portions of the sheath are over a ridge. 
     
     
         12 . A method of medical treatment comprising:
 inserting a medical device of  claim 1  into a patient's blood vessel;   inflating the balloon;   disrupting the sheath at the weakened portions; and   releasing the therapeutic agent.   
     
     
         13 . The method of  claim 12 , wherein the weakened portions are perforation lines, wherein inflating the balloon causes tearing of the sheath along one or more of the perforation lines, and wherein the therapeutic agent is released through the tear in the sheath. 
     
     
         14 . The method of  claim 12 , wherein the weakened portions are arranged in a grid-like pattern, and wherein inflating the balloon causes fragmentation of the sheath. 
     
     
         15 . The method of  claim 14 , wherein the size of at least some of the fragments is 100 μm or less. 
     
     
         16 . The method of  claim 13 , wherein the weakened portions extend substantially radially along the sheath. 
     
     
         17 . The method of  claim 12 , wherein the weakened portions of the sheath are areas of the sheath that are attached to the balloon. 
     
     
         18 . The method of  claim 12 , wherein the weakened portions of the sheath have a different thickness or different composition that another portion of the sheath.