Drug-eluting stents best used in select patients

New study results published in the Lancet in September found that the use of drug-eluting stents (DESs) may be less cost-effective than bare-metal stents when used in all angioplasty patients. The results indicate that use of DESs should be limited to elderly patients in high-risk groups.

In the Basel Stent Cost-Effectiveness (BASKET) Trial, patients were randomized to receive treatment with a sirolimus-eluting stent (Cypher, Johnson & Johnson), a paclitaxel-eluting stent (Taxus, Boston Scientific), or a bare-metal cobalt-chromium-based stent (Vision, Guidant Corp). A group of 826 patients was treated with angioplasty and stenting for 1,281 de-novo lesions and was followed up for six months for incidence of major adverse cardiac events and cost.

Results showed that death, myocardial infarction, or target vessel revascularization occurred in 7.2% of patients treated with one of the DESs compared with 12.1% of those treated with bare-metal stents. There were no significant differences observed between the two DES groups. At six months, total costs were higher with DES-a mean of approximately $13,161 compared with $12,031 for treatment with a bare-metal stent.

Earlier this year, the ESC Taskforce for Percutaneous Coronary Intervention developed the first-ever guidelines for the use of DESs, based on evidence from clinical trials. The authors noted that only the Cypher and Taxus stents have shown significantly positive effects in studies with clinical endpoints and recommended that DES use focus on the enrollment criteria of the TAXUS-IV, TAXUS-VI, and SIRIUS (sirolimus-coated stent) studies. The authors also highlighted the need for larger trials with adequately powered primary clinical endpoints that justify a change in clinical practice.

Clopidogrel (Plavix, Sanofi-Aventis) should be used, in addition to aspirin, for at least six months following stent placement to avoid thrombosis, according to the guidelines. DESs should therefore not be implanted in patients with upcoming extra-cardiac surgeries, and the use of bare metal stents may be a safer option in this group.

In a related article published in the Journal of the American Medical Association last month, Boston Scientific's paclitaxel-eluting stent, Taxus Express², was shown to significantly reduce the risk of target lesion revascularization nine months following angioplasty from 15.7% to 8.6%. Additionally, target vessel revascularization was reduced from 17.3% to 12.1%. According to Hank Kucheman, MBA, president of the company's interventional cardiology business, no other DES has been studied in such complex patients and lesions before.

The study (TAXUS V) included 1,156 patients who underwent stent implantation for single coronary artery stenosis, but it also included 664 patients with complex or previously unstudied lesions. Thirty-three percent of patients required the use of multiple stents.

Some cardiology experts believe that, while these two studies did show that the use of DESs is an improvement over bare-metal stents in certain situations, there is still room for progress.

"It is becoming increasingly clear that DESs have not abolished the restenotic process, and especially in high-risk lesions, target vessel revascularization rates exceed 10%," wrote Antonio Colombo, M.D., and John Cosgrave, M.D., in an editorial accompanying the JAMA article. They believe the future of DESs may involve thinner stents or devices delivering multiple medications.

In fact, according to Boston Scientific, the company hopes to introduce TAXUS Liberte in the United States sometime in 2006, pending Food & Drug Administration approval. Currently being launched in Europe, the device would be the first in a new generation of DESs with improved deliverability and flexibility.

Separately, Angiotech Pharmaceuticals, which is developing Zilver, a paclitaxel-eluting stent, to treat peripheral arterial disease, has launched a Web site about the product ( http://www.zilvertxtrial.com/).