Device for treating vulnerable plaque

Abstract

A method of treating vulnerable plaque comprising intentionally damaging or rupturing the vulnerable plaque using a wingless balloon which is inflated from a wingless unexpanded diameter to a limited expanded diameter. This process produces significant increase in ECM synthesis at the site of the damage or rupture. As a result, the method strengthens the vulnerable plaque while minimizing or avoiding damage to the surrounding wall of the body lumen or damaging a stable plaque mistakenly believed to be a vulnerable plaque. The method of the invention is particularly useful in treating a fibroatheroma type of vulnerable plaque. In one embodiment, the balloon is self-limiting such that it expands compliantly at initial inflation pressures, and above nominal pressure it expands noncompliantly. In an alternative embodiment, the balloon is inflated using a diameter-limiting device, such as a device which limits the inflation pressure or the volume of inflation fluid in the balloon.

1 . A device for treating vulnerable plaque, comprising a balloon catheter having a wingless balloon with an unexpanded diameter which inflates to an expanded diameter wherein such expanded diameter is selected to intentionally damage such plaque by disrupting a fibrous cap without cap rupture, to thereby strengthen the vulnerable plaque by inducing extracellular matrix protein synthesis. 
   
   
       2 . The device of  claim 1 , wherein said expanded diameter corresponds to the diameter of a portion of body lumen in which the vulnerable plaque is located, whereby the vulnerable plaque can be damaged without damaging the body lumen wall adjacent to the vulnerable plaque. 
   
   
       3 . The device of  claim 1 , wherein said catheter is configured for delivering an antithrombotic agent within the body lumen. 
   
   
       4 . The device of  claim 1 , wherein the balloon has a highly compliant radial expansion up to a nominal expanded diameter within a first inflation pressure range, and a low compliant radial expansion within a second higher inflation pressure range. 
   
   
       5 . The device of  claim 4 , wherein the balloon has at least one layer formed of a polymeric material selected from the group consisting of expanded polytetrafluoroethylene, and expanded ultrahigh molecular weight polyolefin, and the balloon is inflated at an inflation pressure within the second higher inflation pressure range. 
   
   
       6 . The device of  claim 5 , wherein the balloon is inflated at an inflation pressure of about 10 atm to about 20 atm. 
   
   
       7 . The device of  claim 5 , wherein the at least one layer of expanded polytetrafluoroethylene, and expanded ultrahigh molecular weight polyolefin is porous with an antithrombotic agent within the pores. 
   
   
       8 . The device of  claim 4 , wherein the balloon expands to an expanded diameter of about 2% to about 15% greater than the nominal diameter within the second, higher inflation pressure range. 
   
   
       9 . The device of  claim 1 , further comprising a diameter-limiting inflation device. 
   
   
       10 . The device of  claim 9 , wherein the diameter-limiting device comprises a pressure relief valve within a proximal adapter of the balloon catheter, which limits the pressure in the balloon to about 4 to about 10 atm. 
   
   
       11 . The device of  claim 1 , wherein the balloon is expandable to a working, nominal outer diameter with a highly compliant radial expansion within a working pressure range of the balloon. 
   
   
       12 . The device of  claim 11 , wherein the outer diameter of the balloon increases by about 40% to about 400% of an uninflated outer diameter of the balloon within the working inflation pressure range of the balloon. 
   
   
       13 . The device of  claim 1 , wherein the balloon is formed of a polymeric material selected from the group consisting of polyurethane elastomers, silicone polyurethanes, segmented polyamide block copolymers, segmented polyester block copolymers, styrene butadiene rubber, and radiation crosslinked polyolefinic elastomers.