THURSDAY, Oct. 30, 2003 (HealthDayNews) -- U.S. health officials are warning that a revolutionary heart stent coated with a drug designed to prevent blood clots has been associated with at least 60 deaths.
The Food and Drug Administration said Wednesday it had received more than 290 reports of clotting during the month after the Cypher stent was implanted in patients. More than 60 people died. In the remaining cases, "the device was associated with injury requiring medical or surgical intervention," the FDA said.
An additional 50 reports, also including some deaths, were attributed to "possible hypersensitivity reactions" with symptoms such as rash, pain, fever, hives and itching, the agency said in a statement.
The FDA did not suggest abandoning the device and is simply urging physicians to follow best-practices guidelines.
"At this point, there's no evidence that really indicates that there's any excess or unexpected adverse effects with the stent after approval as compared to what our expectation was in reviewing the premarket information," said Dr. Neil Muni, medical officer for the divison of cardiovascular devices at the FDA.
Physicians on the front lines also do not see the warning as a cause for undue alarm.
"There is absolutely no question that the stents are a big advance in terms of efficacy for the patient," said Dr. John Hodgson, president of the Society for Cardiovascular Angiography and Interventions and professor of medicine at Case Western Reserve University in Cleveland.
"Yes, it's unfortunate that this is happening, but the absolute frequency is very low -- and lower than what was reported in randomized clinical trials and lower than what we have accepted for the last 15 years [from bare metal stents]. This is not a surprise," Hodgson added.
The incidence rate is about 50 times higher in bare metal stents, Hodgson said.
Bare metal stents have been used for more than a decade to prop open arteries that are cleared by angioplasty. Unfortunately, the devices tend to provoke inflammation and scarring, which can cause the artery to close over again.
The new stents, made by Cordis Corp., a division of Johnson & Johnson, are coated with a thin polymer containing an antibiotic called siroliumus, which is slowly released into the patient to decrease inflammation and scarring and, thus, re-blockage of the artery.
Dr. Samin Sharma, director of the cardiac catheterization lab and intervention at Mount Sinai School of Medicine in New York City, believes that inadequate anti-platelet therapy after the device was implanted may have contributed to some of the incidences of clotting in recent months.
The other possible reason for the high-profile of these cases is that no one is alerting the FDA to problems with bare-metal stents any more, Sharma added. In the last six months, Mount Sinai has implanted drug-eluting stents in about 900 patients and four have developed clots, which works out to less than 0.5 percent. The rate was equivalent for patients receiving bare metal stents in the same time period, Sharma said.
"This can be taken care of if people pay attention to it," Sharma said. Some medical centers may also be using the drug-eluting stents for more complex blockages, adding to the complication rate.
"It's important for patients to take the appropriate medications after the procedure," said Dr. Sidney Smith, professor of medicine at the University of North Carolina, Chapel Hill and chairman of the American College of Cardiologists/American Heart Association committee to update angioplasty guidelines. "It's also important that physicians deploy the stents correctly."
The FDA pointed out in its statement that hundreds of thousands of patients have successfully received the stent in the last several months.
Physicians are being asked to report adverse events associated with the Cypher stent to the FDA.
"They [the FDA] are not recommending that anybody change anything," Hodgson said. "It's an alert in the sense that they want to keep people informed and in some ways they're covering themselves. It's part of the normal assurance process that the FDA provides for us, and we consider that to be welcomed. We're not alarmed by the numbers."
At the behest of the FDA, Cordis is conducting post-approval studies and continuing follow-up on patients with the stent. Such a practice is not uncommon, the FDA's Muni said, "certainly for a first-in-class device."
Whether any future action is required will depend on what the FDA discerns from physician's voluntary reports.
"Clearly there is no evidence at this point that would indicate any action on our part," Muni said. "If we start getting evidence that this is a pattern or causality and/or any evidence that rates are indeed in excess of what would be expected, we would take the appropriate action. That would be true of any medical device."
Cordis spokesman Marty Schildhouse said the company sent letters to physicians in July apprising them of 47 "events" in 50,000 patients. So far, 450,000 of the coated stents have been installed in about 300,000 patients, with an "event rate" of about 0.06 percent globally and 0.1 percent in the United States.
"The rate of thrombosis [clotting] has not changed, and it's still below that of bare metal stents," Schildhouse said. "Thrombosis exists with stents because they're metal objects, and any drug-eluting stent is not designed to reduce the rate of thrombosis. It's designed to reduce re-clogging."
The clot rate of the Cypher stents is "consistently below that of bare metal stents and you would hope that this would be the case going forward," he said.