Drug stents more likely to clot blood – analysis

CHICAGO – Blood clotting is four to five times more likely to occur in patients who have drug-coated heart devices known as stents, compared with the older bare- metal variety, according to a large data analysis by the Cleveland Clinic released Wednesday. The analysis comes one week before a U.S. Food and Drug Administration panel of experts meets to discuss late stent thrombosis, or potentially fatal blood clotting, long after the devices, also known as drug-eluting stents, are implanted. The Cleveland Clinic analysis of 14 studies with 6,675 patients will likely fuel a growing debate about the safety of drug-coated stents, the tiny wire-mesh devices used to prop open surgically cleared arteries. Thrombosis, or blood clots, can lead to heart attacks. The release of the study in the December issue of the American Journal of Medicine said trials using the stents coated with sirolimus, the drug Johnson & Johnson used on its device, mandated anti-clotting medication for at least two to three months, while stents coated with paclitaxel, the drug Boston Scientific Corp. uses, required six months. “Our analysis found that there is a small, but real hazard of late stent thrombosis with drug-eluting stents more so than with bare-metal stents, likely in the setting of discontinuation of anti-clotting drugs,” said Dr. Deepak Bhatt, a Cleveland Clinic official, in a prepared statement. “This does not mean that drug-eluting stents should not be used, as other studies have shown that they do significantly reduce the need for repeat procedures compared with bare metal stents,” added Bhatt, associate director of the clinic's Cardiovascular Coordinating Center and one of the study's authors. Drug-coated stents quickly supplanted bare metal stents when they were introduced a few years ago because the incidence of reclogging, known as restenosis, is sharply reduced. The shares of companies that manufacture drug-coated stents have fallen recently amid concern the FDA panel will highlight the risks of the medical devices. Dr. Steven Nissen, chairman of the Department of Cardiovascular Medicine at the Cleveland Clinic, and Dr. Eric Topol, formerly of the Cleveland Clinic and recently named chief academic officer and chief of genomic medicine and translational science for Scripps Health, are on the panel, according to people familiar with it. The FDA Web site lists doctors who required conflict of interest waivers to be on the panel. Among them is Dr. Robert Harrington, director of Cardiovascular Clinical Trails at Duke University Medical Center. Nissen, Topol and Harrington have all expressed concern about the safety of the devices over the years. Wall Street analysts expect Nissen, who is also the chairman of the American College of Cardiology, to be a strong force on the panel and advocate curtailing the use of drug- coated stents in certain patients. Boston Scientific, which generates a lion's portion of its revenues from stents, and J&J, which recently agreed to acquire stent maker Conor MedSystems Inc. , are the only two companies approved to sell drug-coated stents in the United States. Abbott Laboratories Inc. and Medtronic Inc. ,which sell drug-coated stents outside the United States, are gearing up for U.S. launches in mid-2007 or early 2008. There already has been a 5 percent to 7 percent decline in the use of drug-coated stents, noted Dr. William O'Neill, Professor and Executive Dean for Clinical Affairs at the University of Miami's Miller School of Medicine. O'Neill expects greater use of anti-clotting drugs such as Plavix, especially if the stent is placed in an area that poses a greater risk of heart attacks. In some cases, he said, life- long anti-clotting drugs may be prescribed. He said it also is important for the panel to consider the type of heart attack. Attacks resulting from a clot can be life-threatening, whereas those caused by the reclogging of the vessel where the stent was placed are much less serious. “Boston Scientific is trying to make restenosis some terrible thing. They've never proven that to be. It's a gradual build-up of tissue and there's usually a warning when that happens and the patient goes to the hospital,” said O'Neill. But he added that the absolute risk of clotting was very low – about one in 200. “I do think people are losing their perspective,” he said. Boston Scientific and J&J shares were down 7 cents each at $16.00 and $65.90, respectively, in afternoon trading on the New York Stock Exchange. Abbott shares were up 42 cents at $46.82 and shares of Medtronic were up 5 cents at $52.70.

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