MONDAY, Nov. 13, 2006 (HealthDay News) -- The question isn't so much whether to use stents on heart patients, but which stent to use.
New evidence emerging at the annual meeting of the American Heart Association (AHA), in Chicago, suggests that drug-eluting stents may not be completely safe over the long term.
"This is a topic extremely important to the cardiology community," said Dr. Sidney Smith Jr., past president of the AHA and director of the Center for Cardiovascular Science and Medicine at the University of North Carolina at Chapel Hill. "We may not have a war on our hands, but certainly a very spirited discussion about where we stand, what we know and possibly what action we might need to take."
Smith moderated a news conference Monday that dealt with the issue of stents.
Narrowing of an artery -- called stenosis -- is commonly treated with balloon angioplasty and insertion of a stent, a wire mesh tube that props open the artery. Drug-eluting stents, first approved in 2003, slowly release drugs to prevent scarring and possible restenosis, or re-closing of the vessel.
Drug-eluting stents have quickly eclipsed bare metal stents, accounting for some 80 percent to 90 percent of placements, according to experts speaking at the news conference.
"We try to use stents whenever possible and drug-eluting stents whenever possible," said Dr. David Williams, senior author of one of the studies and professor of medicine at Brown University Medical School in Providence, R.I. "Some, however, have raised concerns that drug-eluting stents may be associated with an increased risk of stent thrombosis [blood clots] in follow-up and may lead to death and heart attacks."
"They are used in the majority of cases, but the long-term outcome in the real world is not known," echoed Dr. Joseph B. Muhlestein, professor of medicine at the University of Utah in Salt Lake City.
The bottom line? "Cardiologists are now faced with the decision of what type of stent to use," Williams said. "The issues are related to safety and efficacy and magnitude of prevention of recurrent procedures."
Williams' study compared patients treated with bare metal stents and with drug-eluting stents in a routine-practice population. Of more than 3,000 patients studied, one-year adverse event rates were similar, although bare metal stent patients were more likely to require follow-up revascularization or bypass surgery. In-hospital and one-year death rates were not statistically significantly different, Williams said. The success rate was similar in both groups -- about 98 percent.
"These data support the use of drug-eluting stents in routine clinical practice," Williams said.
Muhlestein's study, however, found that the all-cause death rate was higher in patients treated with drug-eluting stents than in those treated with bare metal stents after three years.
"Given the current dominance of drug-eluting stents in current practice, certainly we think these findings raise concern," Muhlestein said. "We need more long-term scrutiny."
Yet another study, this one conducted in the Netherlands, compared two different types of drug-eluting stents (sirolimus-eluting stents and paclitaxel-eluting stents) and found little difference in outcomes.
Experts on Monday debated the implications of the new evidence.
"I don't believe there is a difference in death or heart attack that's been demonstrated between drug-eluting stents and bare metal stents at this point," Williams said. "I would attempt to put in drug-eluting stents, although I do think there are technical instances where delivery of the bare metal stent is easier."
Muhlestein said: "To some degree, I agree, but our study unexpectedly found this increase in death, which led me to wonder whether maybe we're being too aggressive. Perhaps we ought to consider other alternatives for complex patients." He added that he would not stop using drug-eluting stents but would consider them more carefully.
Dr. John Kao, assistant professor of medicine at the University of Illinois, Chicago, and author of a study that found that privately insured patients were most likely to get drug-eluting stents, had this to say: "There is a cause for concern about the long-term safety profile of drug-eluting stents, but, right now, there's no definitive evidence suggesting that they are a cause of increased morality."
Much rests on the duration of anti-platelet therapy given after insertion of a stent. Guidelines issued earlier this year recommend anti-platelet therapy for up to six months, depending on the type of stent used, with use continuing up to one year also reasonable, Smith said.
Since then, however, "evidence has continued to gather that too many patients stop anti-platelet therapy before even completing a month, which puts them at significant risk," Smith said. "Then, a series of presentations at the World Cardiology Congress in Barcelona suggested that we might need to think even more seriously about the nature of anti-platelet therapy and its duration."
"Longer duration of anti-platelet therapy is probably going to turn out to be one of the factors," Kao agreed.
"It's concerning," said Dr. Nieca Goldberg, AHA spokeswoman and chief of women's cardiac care at Lenox Hill Hospital in New York City. "The question is, what's a doctor to do? And there's a lack of guidelines. We have to have a wider view of new technology."
Visit the American Heart Association for more on stents.