ORLANDO — The proven indications for drug-eluting stents in coronary arteries have expanded, based on results from two studies reported at the annual meeting of the American College of Cardiology.
Sirolimus-eluting stents were more effective than bare-metal stents for preventing restenosis and other adverse events in 322 patients with complex lesions, Henning Kelbaek, M.D., reported at the meeting.
In a separate study, TAXUS-V, paclitaxel-eluting stents also were more effective than bare-metal stents in more than 400 patients with narrow or wide coronaries, said Gregg W. Stone, M.D.
However, when two or more paclitaxel stents were used in an overlapping fashion in long lesions, they led to transient side-branch narrowing that boosted the rate of periprocedural myocardial infarctions, said Dr. Stone, a cardiologist at Columbia University in New York.
“The clinical outcomes of side-branch occlusions tend to be benign,” commented Sheldon Goldberg, M.D., director of interventional cardiovascular medicine at Hahnemann University in Philadelphia. “But the increased risk of non-Q-wave myocardial infarctions in patients who got overlapping stents needs further delineation,” he said.
The study with paclitaxel-eluting stents enrolled 1,172 patients at more than 20 U.S. centers. Included were more than 700 patients with especially narrow or wide coronary arteries, or with long lesions that required more than one stent. The TAXUS-V study was funded by Boston Scientific, the company that markets the paclitaxel-eluting stent (Taxus).
The study included 379 patients with long lesions—average length of about 25 mm—who received two or more stents in their target artery; 326 of these patients had stents placed in an overlapping fashion. After 9 months of follow-up, the rate of major adverse events was 20.4% in patients who received paclitaxel-eluting stents, and 32.0% in those who received bare-metal stents. Angiography after 9 months in 88% of the patients showed a binary in-segment restenosis rate of 27.2% in patients who got drug-eluting stents and 57.8% in those who got bare-metal stents.
But the 30-day follow-up showed an increased rate of periprocedural MIs among the patients who got multiple paclitaxel-eluting stents, an 8.3% rate, compared with a 3.3% rate among patients who received bare-metal stents. This difference was driven by a 7.3% incidence of non-Q-wave MIs in patients who got paclitaxel-eluting stents. This increased early incidence of MIs was caused by myonecrosis from transient side-branch narrowing and decreased blood flow, Dr. Stone said. This disparity in the rate of MI persisted at 9 months, when there was a cumulative 8.3% rate among patients treated with paclitaxel-eluting stents and a 3.9% rate among patients who received bare-metal stents.
The study subgroup that focused on narrow arteries included a total of 203 patients with an average reference vessel diameter of about 2.1 mm. After 9 months of follow-up, the patients who received paclitaxel-eluting stents had an 18.9% incidence of major adverse coronary events, compared with a 26.9% rate among the patients treated with bare-metal stents. Angiography after 9 months in 88% of these patients showed a binary in-segment restenosis rate of 31.2% in patients who received drug-eluting stents compared with a 49.4% rate in those who got bare-metal stents, reported Dr. Stone, who is a consultant to and receives research support from Boston Scientific.
The subgroup that focused on patients with wide coronary arteries included 202 patients who were treated with 4.0-mm stents. The average reference vessel diameter for patients in this subgroup was about 3.4 mm. After 9 months, the rate of major adverse events was 6.5% among patients who received paclitaxel-eluting stents and 14.9% among the patients who received bare-metal stents.
Angiography after 9 months in 85% of patients showed a binary, in-segment restenosis rate of 3.5% in patients with drug-eluting stents and 14.4% among those with bare-metal stents.
The study using sirolimus-eluting stents in complex lesions, called SCANDSTENT, was done at four centers in Denmark. Although the study received some funding from Cordis, the company that markets sirolimus-eluting stents (Cypher), the study was run independently by Dr. Kelbaek and his associates.
They enrolled 115 patients with a totally occluded coronary artery, 109 with lesions at bifurcations, 73 patients with ostial lesions, and 25 patients with angulated vessels. All affected arteries were native vessels, 2.25–4.0 mm in diameter, with de novo lesions. About half of the patients had non-ST-segment elevation MIs, and 18% had diabetes.
After 6 months, follow-up angiography showed that the binary restenosis rate was 2.0% among the 163 patients who received sirolimus-eluting stents, compared with a 31.9% rate among the 159 patients who received bare-metal stents, said Dr. Kelbaek, a cardiologist at Rigshospitalet in Copenhagen.