Sirolimus Heart Stent Improves Patient Outcomes

NEW YORK (Reuters Health) - Coronary arteries are less likely to reclog in patients who receive stents coated with the drug sirolimus (Cypher; Cordis, Johnson & Johnson) compared with a paclitaxel-coated stent (Taxus, Boston Scientific), the results of three newly published studies suggest. The difference appears to be more pronounced in patients with diabetes.

Multiple clinical trials have established a therapeutic benefit of sirolimus- or paclitaxel-coated stents over bare metal stents, tiny mesh tubes used to prop open clogged coronary arteries. Questions remain concerning the comparability of the two drug-coated stents.

The latest findings are published in the Journal of the American Medical Association and in The New England Journal of Medicine.

In one of the NEJM studies, Dr. Stephan Windecker from University Hospital Bern in Switzerland and his associates conducted a trial involving 1,012 patients with stable heart disease who were randomly assigned to receive a sirolimus stent or a paclitaxel stent.

The primary study end point -- death from cardiac causes, heart attack or reclosure of the coronary artery -- occurred in 6.2 percent of patients in the sirolimus group and 10.8 percent of those in the paclitaxel group.

The difference was driven primarily by a 44-percent reduction in the risk of reclosure of the coronary artery (4.8 percent versus 8.3 percent).

Among the 201 patients with diabetes, the difference in the primary end point between stents was wider than that among nondiabetic subjects.

In a second article in the NEJM, Dr. Adnan Kastrati, at Deutsches Herzzentrum in Munich, Germany, and his associates restricted their analysis to 250 patients with diabetes undergoing heart surgery. Equal numbers were randomly assigned to the two types of stents.

Kastrati's group found that patients in the sirolimus group had less narrowing and reclosure of the coronary artery than did patients in the paclitaxel group.

The same team also reports in the Journal of the American Medical Association the results of a review of six studies that compared the two devices in 3,669 patients with coronary artery disease.

During 6 to 13 months of follow-up, a second procedure was required in 5.1 percent of 1845 patients assigned to the sirolimus stent and 7.8 percent of 1824 patients assigned to the paclitaxel stent.

All three papers showed that the rates of cardiac death or heart attack were low and did not differ significantly between groups.

Dr. David J. Moliterno, a cardiologist at the University of Kentucky in Lexington and author of an accompanying editorial in the NEJM, told Reuters Health that "the large majority of patients...will have extremely terrific outcomes with either stent."

However, the Cypher stent may be useful in more complex cases, such as insulin-dependent diabetics, those with kidney disease or patients who have already had a stent implanted and now require second procedure.

He noted that it's unlikely that the components influencing the differences in outcomes will ever be identified, since new stents with various stent struts, polymers and drugs are under development.

"Because the rate of failure is so low, future studies will need to be either very large or among particularly high-risk patients to discern a possible difference between future generation stents," he said.

SOURCE: Journal of the American Medical Association, August 17, 2005; The New England Journal of Medicine for August 18, 2005.