ORLANDO, Fla. - Patients who received drug-eluting stents were no more likely to die or suffer a heart attack than those who got bare-metal versions, researchers found in a large US study that adds to the debate over the safety of the artery-opening devices.
Fears that drug-releasing stents carry a greater risk of blood clot formation have hurt sales of the devices, sold in the United States by Natick-based Boston Scientific Corp. and Johnson & Johnson. Blood clots that form inside the stent a year or more after the device is implanted, known as late stent thrombosis, emerged in studies of patients in Europe.
In the largest follow-up study to look at the safety of bare-metal vs. drug-coated stents in the United States, presented yesterday at the annual meeting of the American Heart Association, researchers looked at death and heart attack rates but did not break out data on stent thrombosis.
"It has been a long debate over the safety of drug-eluting stents," said Dr. Laura Mauri, a Harvard Medical School professor and lead investigator of the study. "We find the results very reassuring."
The study analyzed data on 20,654 stent patients in a Massachusetts database that monitors the quality of cardiac care at nongovernment hospitals in that state. About 65 percent of the patients received a stent coated with a drug to reduce renarrowing of the artery and the rest got a metal stent without a drug coating.
The Massachusetts study followed patients whose stents were implanted between April 2003 and December 2004. Two years after the procedure, 9.4 percent of patients who received the drug-coated devices had died, compared with 11.9 percent of patients who got bare-metal stents.
The incidence of heart attacks was also similar in both groups.
"It confirms in real-world practice what has been seen in randomized clinical trials," said Dr. Raymond Gibbons, a cardiologist at Mayo Clinic. He said factors such as patient selection and differences in the number of patients referred for angioplasty made it difficult to compare the Massachusetts trial with European studies.
Stents are tiny wire mesh tubes inserted into a blood vessel in the groin or leg and then threaded through to the coronary artery to help keep it open after it has been cleared of a blockage during an angioplasty procedure. Drug-coated stents, first introduced in 2003, incorporate medicines to prevent the artery from reclosing.
