Use of a perforated balloon catheter to deliver concentrated heparin into the wall of the normal canine artery.

A perforated catheter was used to deliver either horseradish peroxidase or fluoresceinated heparin under pressure to the canine arterial wall. Depth of penetration of the media by horseradish peroxidase was dependent on perfusion pressure. At 5 bar pressure for 1 min, the entire media showed a reaction product for horseradish peroxidase. Fluoresceinated heparin delivered under the same conditions could be demonstrated to traverse the entire media as well. A pressure of 5 bars caused medial necrosis at 48 h after perfusion, even when the perfusing solution was saline. (This did not differ from the effect of standard angioplasty at the same pressure.) However, heparin at 5,000 U/ml did not cause medial alteration at 48 h when delivered at the lower pressure of 500 mm Hg. It is feasible to deliver heparin over 1 min in high concentration to the arterial wall by means of this balloon catheter. This method may permit the use of commercially prepared heparin in high concentration as an antiproliferative agent to control the problem of restenosis after angioplasty.