Two new studies conducted on drug-eluting stents, comparing them with the conventionally used bare-metal type of stents, suggest that the drug coated ones are safe to implant in patients who have suffered severe heart attacks. However, it also advocated larger trials with a longer follow up, before the drug-eluting stents could be routinely implanted for all patients of heart attack. In view of the emerging studies which suggested that the drug-eluting stents posed a risk of late-stent thrombosis, a complication in which blood clots were formed after more than six months subsequent to the device being implanted which could lead to heart attacks and strokes, heart patients and doctors had started to question whether these coated stents were worth the extra expense.
A Stent is a tiny wire-mesh tube which is used after an angioplasty to help keep the narrowed arteries remain open. A drug-eluting stent is a stent which is impregnated with medicines that help prevent the re-narrowing of the arteries around the stent, so as to help keep the blood flowing through these arteries. Drug-eluting stents were introduced three years ago as a more efficient way to treat heart patients and an approximate 6 million heart patients all over the world have been implanted with these coated stents.
In one trial of 712 randomly assigned heart attack patients who were implanted with either a Johnson & Johnson's Cypher stent or a bare-metal stent, it was found that 7.3 percent of the Cypher implanted patients needed a repeat procedure as compared to 14.3 percent of their counterparts who had been implanted with a bare-metal stent. This showed that Cypher stent was better in reducing the regrowth of artery clogging tissue, thus keeping blood flow through the arteries, as compared with the conventional bare-metal stent.
The second study involving Boston Scientific Corp.'s Taxus stents as compared to bare-metal stents, included 619 patients, all implanted either with Taxus stent or a bare-metal stent, after suffering a heart attack. The researchers found no statistically significant differences between the two groups implanted with either stents, during the follow-up period of 12 months.
Dr. Frans Van de Werf, professor and chairman, department of cardiology, University Hospital Gasthuisberg, Leuven, in Belgium said that since the two brands of drug-eluting stents had not been compared in a test confronting each other, it would be dangerous to draw conclusions that one brand was better than the other. The present studies offered no proof that one stent was superior as compared to the other one. Van der Werf has authored an editorial which is accompanying the two studies, in the New England Journal of Medicine. He believes that the trials were too short to draw any definite conclusions and "direct comparative trials of uncoated vs. drug-eluting stents, with long follow of more than one year," was required.
Dr. David Brown who is chief of cardiovascular medicine at the Stony Brook University Medical Center said: "This is a classic kind of thing. Every time we have a technological breakthrough, we invent a new disease along with it. In this case, it's late-stage thrombosis ."
The study details have been published in the September 14 edition of the New England Journal of Medicine
