Method and catheter system for delivering medication with an everting balloon catheter

Claim 1

A process of applying a medication to a diseased portion of a blood vessel with a catheter having a balloon connected to distal ends of inner and outer tubes, comprising: providing a balloon catheter having an inner and outer tube which are longitudinally adjustable with respect to each other, and a balloon affixed at opposing ends of the balloon to a distal end of one of the inner and outer tubes; the balloon defining a medication portion, and a lumen being defined between the inner and outer tubes; applying a coating of medication to the medication portion of a surface of the balloon; positioning distal ends of the inner and outer tubes in closely spaced relationship and folding the balloon on itself such that the balloon assumes an annular everted shape defining inner and outer balloon layers, wherein the entire balloon surrounds some portion of one of the inner and outer tubes; the medication portion of the balloon being arranged on the inner layer which is internal, and the balloon having a shielding portion of the balloon on the outer layer which surrounds the remainder of the balloon; inserting the catheter into the vessel and positioning the balloon adjacent the diseased portion of the blood vessel; inflating the balloon by delivering fluid through the lumen defined between the tubes and communicating with the balloon; continuing the inflation until the shielding portion engages the vessel adjacent the diseased portion; longitudinally adjusting the inner and outer tubes relatively to unfold the balloon as the inflation continues, thereby bringing the medication portion into contact with the diseased portion of the blood vessel, to apply the medication to the diseased portion; and deflating the balloon and removing the catheter from the vessel.