Patients given drug-coated stents after an acute heart attack are nearly five times more likely to die six months to two years later than those with bare metal forms of the arterial scaffolding, research showed on Tuesday.
The finding, from a two-year analysis of 2,300 patients in 14 countries, fuels the debate over the safety of so-called drug-eluting stents, made by the likes of Boston Scientificand Johnson & Johnson .
Doctors at the European Society of Cardiology said the finding showed the need to be very selective about giving drug stents to the right patients.
Gabriel Steg of the Hospital Bichat-Claude Bernard in Paris followed the fate of patients who were given stents – tiny wire-mesh tubes used to prop open clogged heart arteries -- following a ST segment elevation myocardial infarction (STEMI), the most deadly kind of heart attack.
For the first six months, those on drug stents did as well as those on bare ones. But after 180 days, their paths diverged and the drug stent patients were 4.7 times more likely to die, with a mortality rate of 8.6% seen.
Steg said the trend probably reflected the high thrombosis risk in this group of patients, who represent an estimated 10% to 20% of coronary stent procedures.
Drug stents are known to carry a small risk of blood clots after the first year, known as "late stent thrombosis." This occurs in less than 1% of patients but kills nearly half of those affected.
Steg said many heart patients with less acute conditions could still benefit from drug stents, which help prevent arteries narrowing again.
"I still believe there is room for DES in many patients and I disagree with the concept of banning DES altogether," Steg told reporters. "There are candidates for DES (drug-eluting stents), but these happen to not be STEMI patients."
Drug stents remain highly controversial in the cardiology community and fears about late stent thrombosis have led to a slump in sales in the past year.
Eckhart Fleck, director of cardiology at the German Heart Institute in Berlin and a spokesman for the European Society of Cardiology, said the findings were serious and showed that doctors should not be indiscriminate in use drug stents.
But Johnson & Johnson said in a statement the results were inconsistent with the findings of other analyses of patient records and with all currently available randomised controlled trials.
A Swedish study presented on Sunday, involving 35,000 patients, found no overall increased risk for heart patients between drug and bare stents after four years of follow-up -- a reversal of the same researchers' earlier three-year findings that patients with coated stents were more at risk.
Spencer Grace, a cardiologist at Altanta Piedmont Hospital and a spokesman for the American College of Cardiology, said patient selection appeared to be key.
"STEMI is not a particularly good indication for drug-eluting stents for a host of reasons, because what you gain is very small since there is a not a lot of restenosis (artery renarrowing) in these patients," he said.
"The main thing you are trying to do with these patients is open the artery and stop the heart attack and that is done no better with a drug-eluting than a bare metal stent."