ATLANTA — Paclitaxel-eluting coronary stents were more effective for treating in-stent restenosis than was vascular brachytherapy in results from a study with almost 400 patients reported at the annual meeting of the American College of Cardiology.
The clear superiority of paclitaxel-eluting stents for this indication matched previously reported results for sirolimus-eluting stents, which were shown to be better than brachytherapy for in-stent restenosis in findings reported last November at the annual scientific sessions of the American Heart Association.
Vascular brachytherapy is currently the only treatment approved by the Food and Drug Administration for treating bare-metal stents that develop in-stent restenosis.
Both comparisons of drug-eluting stents with brachytherapy involved stenoses in bare-metal stents, but drug-eluting coronary stents also worked for treating restenosis in drug-eluting stents in a single-center series of 77 patients, which was reported in a poster at the meeting. The next challenge will be further study in finding the best way to treat restenosis in drug-eluting coronary stents.
The paclitaxel-eluting stent study was conducted at 37 centers in the United States and Canada during June 2003 to July 2004. All patients enrolled had a single, restenotic lesion in a bare-metal stent in a native coronary artery. The patients were randomized to treatment with a paclitaxel-eluting stent or vascular brachytherapy using any Food and Drug Administration-approved, β-source radiation system. The study was sponsored by Boston Scientific Corp., which markets the paclitaxel-eluting stent (Taxus) used in the study.
The primary end point was incidence of ischemia-driven target vessel revascularization 9 months after treatment. The rate of this event was 10.5% in 194 patients treated with the paclitaxel-eluting stent and 17.5% in patients treated with brachytherapy, a statistically significant difference in favor of the drug-eluting stent, reported Dr. Gregg W. Stone, professor of medicine and director of cardiovascular research and education at Columbia University in New York. Dr. Stone also is a consultant to Boston Scientific.
The paclitaxel-eluting stent was superior to brachytherapy by several other efficacy measures assessed by angiography after 9 months. Compared with brachytherapy, stenting showed several advantages that contribute to improved long-term patency: greater initial acute gain owing to mechanical scaffolding by the stent, preservation of acute gain by limited late loss, and avoidance of the edge-effect produced by brachytherapy, said Dr. Stone.
Stenting was also at least as good as brachytherapy for both 30-day and 9-month measures of safety. The results were published simultaneously with Dr. Stone's report at the meeting (JAMA 2006;295:1253–63).
“The study is very definitive” for proving the superiority of paclitaxel-eluting stents over brachytherapy, commented Dr. Ron Waksman of the division of cardiology at the Washington (D.C.) Hospital Center, and a pioneer in the development of vascular brachytherapy.
Similar results were reported for sirolimus-eluting stents (Cypher), when compared with vascular brachytherapy for treating restenosis in bare-metal stents in a study by Dr. David R. Holmes Jr., professor of medicine at the Mayo Clinic in Rochester, Minn., and associates.
The published report of those findings appeared in the same journal issue that contained Dr. Stone's paper (JAMA 2006;295:1264–73).
An editorial that commented on both studies noted that the data from the two studies were strong enough to move brachytherapy to a second-line choice for treating in-stent restenosis, although with a few exceptions.
For the time being, brachytherapy remains the top option for treating restenosis in bifurcations; in vessels with excessive calcification, tortuosity, or angulation; or in other settings in which repeated stenting might risk procedure-related ischemic events, wrote Dr. Debabrata Mukherjee and Dr. David J. Moliterno of the University of Kentucky in Lexington (JAMA 2006;295:1307–09). The best treatment for in-stent restenosis in patients with renal dysfunction also is unclear, because those patients were excluded from both of the new studies.
Questions about how to treat in-stent restenosis will now shift to restenosis that occurs in drug-eluting stents, where brachytherapy is unlikely to have a role, wrote Dr. Mukherjee and Dr. Moliterno.
A step toward addressing this issue was made by cardiologists at the Prairie Heart Institute at Saint Johns Hospital in Springfield, Ill. They reported in a poster their experience with using a second drug-eluting stent to treat 86 lesions in 77 patients with restenosis that had occurred in a first drug-eluting stent.
Their findings suggested that using the “opposite” drug-eluting stent the second time around might be the best approach. This seems to be the first report of using drug-eluting stents to treat stenoses that form in drug-eluting stents, said Dr. Marc E. Shelton, a cardiologist at the Prairie Heart Institute.