Coronary artery balloon catheter angioplasty for the treatment of obstructive atherosclerosis has an unacceptably high restenosis rate of about 40% within 6 months. Local delivery of pharmaceuticals and nucleotide-based compounds is under investigation as one means to decrease recurrence. Labeled molecules, when delivered to arterial angioplasty sites in aqueous solution using porous balloon catheters, are quickly lost from the tissue. Alternative strategies include drug encapsulation in microparticles, and implantation of drug-containing polymers. We tested the feasibility of a catheter-based system to deposit a 70-μm thick layer of polyethylene glycol-lactate based hydrogel (polymerized by cross-linked end-terminal acrylate groups) onto the luminal surface of coronary arteries in pigs after balloon angioplasty, and examined the histologic consequences at one hour and seven days using light, scanning electron, and transmission electron microscopy.

At one hour the gel layer was readily visualized by all three microscopic techniques and appeared well adhered to and in intimate contact with the blood vessel surface (Figs. 1-2).