Drug-eluting stents succeed after bare metal stents fail
(BETHESDA, MD)–Once a coronary stent becomes blocked with scar tissue, the likelihood it will become blocked again is 30 percent to 80 percent. Inserting a second coronary stent that slowly releases anti-scarring medication can markedly cut that risk, according to a study in the just-published October 2005 issue of Catheterization and Cardiovascular Interventions: Journal of the Society for Cardiovascular Angiography and Interventions.
Researchers also showed that it was unnecessary to thread a high-tech ultrasound device into the artery to guide precise placement of the drug-eluting stent. Instead, they reduced the risk of blood clotting by minimizing trauma to the artery–no stretching of the artery before or after the procedure, for example–and prescribing a double dose of anti-clotting drugs for two months.
“Our slogan is not ‘Bigger is better,’ but ‘A nice, quick job is better,’” said Dr. Philippe Commeau, of Centre Hospitalier Prive Beauregard in Marseille, France.
Twenty-three patients participated in the ISR II study. All had in-stent restenosis (ISR), an overgrowth of scar tissue inside a bare metal stent. They also had chest pain and some other sign that too little blood was flowing to the heart.
Patients were treated by insertion of a Cypher stent (Cordis Corp., Miami) on top of the original bare metal stent. The Cypher stent slowly releases sirolimus into the artery wall, a medication that prevent the overgrowth of the tissue that causes in-stent restenosis. Interventional cardiologists used standard x-ray angiography to determine the correct placement of the stent.
During two years of follow-up, four patients (17 percent) had yet another procedure to open the stented artery. Two of the patients had no chest pain and showed no evidence of a shortfall of blood flow to the heart. Therefore, the study’s authors pegged the true clinical restenosis rate at only 8.5 percent.
Since the conclusion of the ISR II study, Dr. Commeau and his colleagues have followed the progress of 200 similar patients for more than two years. They expect to publish the results of that study soon.
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