Drug-eluting stents significantly cut the rates of heart attack and repeat procedures

The use of medicated stents markedly improves the clinical outcomes of patients who develop blockages in aging veins surgically grafted onto the heart, according to a just-published study in the November 2005 issue of Catheterization and Cardiovascular Interventions: Journal of the Society for Cardiovascular Angiography and Interventions.

The study found that, compared to conventional bare metal stents, drug-eluting stents significantly cut the rates of heart attack and repeat procedures, both of which are indicators of renarrowing--or restenosis--within the stent.

"There was a fourfold reduction in the incidence of restenosis with the medicated stents," said Dr. Raj Makkar, codirector of the Cardiovascular Intervention Center at Cedars Sinai Medical Center in Los Angeles. "At least over the short term, that's very encouraging."

Drug-eluting stents slowly release medication that prevents the overgrowth of scar tissue inside the stent, and have been shown to significantly reduce the risk of restenosis in the natural arteries of the heart. Treating worn and diseased vein grafts is more challenging, however. In fact, within 5 to 10 years, half of all vein grafts become diseased, necessitating either stenting or repeat bypass surgery in some cases.

The study analyzed data from 223 consecutive patients who had a stenting procedure to restore blood flow through clogged vein grafts, 139 of whom were treated with a drug-eluting stent and 84 of whom were treated with a bare metal stent. Patients had undergone the original bypass surgery an average of nearly 8 years earlier.

During 9 months of follow-up, 4 percent of patients treated with a drug-eluting stent experienced a heart attack, as compared to 20 percent of patients treated with a bare metal stent. Similarly, 10 percent of patients treated with a drug-eluting stent needed a repeat procedure to reopen the vein graft, as compared to 37 percent of patients treated with bare metal stents. The combined rates of heart attack, repeat procedure, and death were 10 percent and 37 percent, respectively.

The Cedars Sinai researchers are continuing to follow-up patients to determine whether drug-eluting stents offer a similar advantage over the long run. Since plaque tends to build up throughout vein grafts, patients may develop new blockages that require additional stenting procedures.

"We can't expect drug-eluting stents to eliminate all problems with bypass grafts, but this study suggests it is reasonable to use medicated stents to treat these patients," Dr. Makkar said.