SCIENCE / MEDICINE : Implant Fights Atherosclerosis

A spongelike plastic device implanted under the skin near arteries may help to prevent hardening of the arteries, researchers from the Harvard Medical School said last week at the ACS meeting.

The implant acts something like a sponge, Dr. Elazer Edelman said, allowing the blood-thinning drug heparin to diffuse through tiny, porelike holes over a period of weeks or months. Tests in animals show that as the drug is released it infiltrates into the arteries, where it appears to inhibit the multiplication of muscle cells that are involved with artery disease.

Researchers think the rapid proliferation of smooth muscle cells is a major contributor to atherosclerosis, hardening of the arteries. When the cells combine with cholesterol within the wall of blood vessels, the result is the formation of fatty deposits that obstruct blood flow and can lead to heart attacks and strokes, studies show.

Edelman said one of the major problems facing researchers in the field of heart disease is how to prevent arteries from clogging up again once they have been cleared through a surgical procedure known as angioplasty. He said heparin has long been used for that purpose, but because it is a blood thinner, it has the potential to cause bleeding when it is administered intravenously. Delivering the drug directly to arteries with the implant may minimize that problem, he said.