TUESDAY, July 10, 2007 (HealthDay News) -- Nearly a third of patients who had drug-coated stents implanted in vein grafts to improve coronary blood flow died within 32 months, Dutch cardiologists report.
There were no deaths among those who had similar vein grafts with traditional bare-metal stents, said the report in the July 10 online issue of the Journal of the American College of Cardiology.
Although the study was small, with only 75 participants, the results call for more research to determine the safety of drug-coated stents in what are known as saphenous vein grafts, American cardiologists said.
"We really do not have definitive evidence whether drug-eluting [coated] stents work in this particular setting," said Dr. Sanjay Kaul, director of the Vascular Physiology and Thrombosis Research Laboratory at Cedars-Sinai Medical Center in Los Angeles.
The saphenous vein, a large blood vessel that runs through the leg and thigh, is often used by cardiac surgeons in coronary artery bypass operations when many such grafts are required, such as occurs in a triple or quadruple bypass. A stent can be implanted to prevent thrombosis -- a clot or blockage of the grafted blood vessel.
The Dutch study included 75 people who had received such grafts, often multiple, because of problems in 96 of the grafted vessels. A total of 60 stents coated with the drug sirolimus were implanted in 47 vessels in 38 patients, while 37 patients got 54 bare-metal stents implanted in 49 blood vessels.
In a follow-up period that averaged 32 months, 11 (29 percent) of the patients who got drug-coated stents died. There were no deaths in the group that received bare-metal stents.
"It is obvious and appropriate to call for more rigorous data on this important subset of patients," wrote Steven Ellis, a cardiologist at the Cleveland Clinic, in a related editorial. He was quick to say that because of a number of issues about the study, including the small number of participants, "It is quite possible, if not likely, that there is no excess risk," Ellis said.
Kaul remained cautious. "These results are not completely surprising," he wrote. "The FDA approved stents on the basis of a highly select patient population, which did not have the characteristics of the people in this particular trial."
It's not possible yet to say why a drug-coated stent might present a great hazard in a grafted vein, Kaul said. Stents in general can be hazardous, because "saphenous veins have softer plaques, which are more prone to develop complications. Also, they can accelerate the process of atherosclerosis." Atherosclerosis ("hardening of the arteries") is the gradual blockage of blood vessels caused by accumulation of fatty deposits called plaque.
Kaul agreed that more studies of the safety of drug-coated stents in saphenous vein grafts are needed.
"Until a definitive study comes out which demonstrates that they are safe, I would stick with balloon angioplasty and bare-metal stents," he said. "They are not very effective, but they are safe."
There's more on bypass surgeries at the American Heart Association.