UT Southwestern Medical Center researchers have found that stents coated with a drug to suppress cell growth are less risky than bare-metal stents in coronary bypass surgery.
Stents are small mesh tubes that reinforce the walls of blocked blood vessels. In this study, stents were used to treat blockages in diseased coronary arteries.
In bypass surgery, grafts are taken from the saphenous vein in the patient's thigh and sewn to the coronary arteries to help improve blood flow to the heart, relieve severe chest pain and reduce the risk of heart attacks from blocked arteries. Years after surgery, those grafts may develop blockages inside the graft that are challenging to treat because of high rates of recurrence.
"Stented vein grafts have a very high risk of re-narrowing - sometimes up to 50 percent when bare metal stents are used," said Dr. Emmanouil Brilakis, assistant professor of internal medicine at UT Southwestern and lead author of the study.
He added: "Drug-eluting stents could provide a solution to this problem, but limited clinical results have been reported to date. The drug-eluting stents examined in our study are coated with a medication called paclitaxel, which inhibits cell growth."
The drug coating is contained on a polymer that covers the surface of the stents and eventually elutes, or washes out of the stent, over a period of several months or years.
For the study, researchers examined 80 patients, roughly half of whom had vein grafts with drug-eluting stents and the other half who had the same procedure with bare-metal stents.
It was found that 51 percent of patients with the bare-metal stent had re-narrowing of the vein graft over several months compared with 9 percent of the drug-eluting stent group.
Also, 28 percent of patients who had a bare-metal stent required another procedure to treat the same blockage, while only 5 percent of patients who had the drug-eluting stent did.
Brilakis said that some of the previous studies have indicated that patients receiving drug-eluting stents in saphenous vein grafts may not reduce the risk of re-narrowing and may be associated with increased risk of death.
"Our findings suggest that drug-eluting stents are a better choice than bare-metal stents for this type of procedure. Patients receiving paclitaxel-eluting stents in our study were significantly less likely to have recurrence of their graft blockage and to require repeat procedures. The rates of death were similar in both study groups, although our study was not designed to detect differences in mortality," he said.
The study is appearing online and in an upcoming issue of The Journal of the American College of Cardiology.