Drug-Eluting Stent Shows Less Effect Over Time

DALLAS, TX -- April 4, 2002 -- A new drug-eluting stent -- a tiny spring device coated with medicine that keeps blood vessels from reblocking after angioplasty -- may have a problem holding up over time, say researchers in today's rapid access publication of Circulation: Journal of the American Heart Association.

"The positive results at six months were not maintained at 12 months," says the study's lead author Antonio Colombo, MD, Centro Cuore Columbus Hospital, Milan, Italy.

Drug-eluting stents contain chemicals that inhibit cell growth in the inner layer of the artery wall. This prevents in-stent restenosis, which can cause a heart attack. In the past, doctors have used lasers, drugs and other techniques to prevent restenosis.

In what researchers call the first clinical experience, they used a stent coated with QuaDS-QP2, a derivative of paclitaxel, a drug that blocks cell growth. The study included 15 patients who had previous angioplasty and had developed new blockages. The average age was 59, and 13 of the patients were men.

Patients' blood vessels were examined at six months and 12 months after stenting. At six months, 13 percent experienced restenosis, and one person died. At 12 months, 61 percent had restenosis and another person had a heart attack.

"The stent appeared to be working at the early stage, but the anti-proliferative effect was not maintained at the 12-month follow-up," he says.

Paclitaxel is a microtubule inhibitor and has been used to prevent cell proliferation in animal models of vascular disease and in treating new vessel blockage in humans. Microtubules are structures in cells that are involved in cell division. This is the first experience using QuaDS-QP2 to treat in-stent restenosis.

"This stent has a plastic sleeve and it's possible that late restenosis could be the consequence of this sleeve, rather than a failure of the drug," says Dr. Colombo.

[American Heart Association]