John Wehr couldn't believe what was he was reading. An article on drug-coated stents, the kind used to prop open his two clogged coronary arteries last June, said the devices have a ''small but significantly increased risk'' of life-threatening side-effects.
Worried, the 78-year-old retired Bethlehem Steel Corp. accountant clipped the article and called his cardiologist. He wasn't alone.
Drug-coated stents tiny mesh tubes coated in chemotherapy drugs have been considered the best medicine had to offer, superior to the uncoated variety in their ability to keep scar tissue at bay and prevent coronary arteries from reclosing.
They've been inserted in 6 million heart patients nationwide, including 5,000 in the Lehigh Valley.
But heart specialists have been forced to reconsider their use since December, when new research showed they are more likely to cause blood clots than do the bare-metal variety and the clots can appear six months to years after the stents are placed.
Clotting is a natural reaction to injury, but studies conducted in the United States and Sweden found that blood clots were getting stuck inside the stents, cutting off blood flow and causing heart attacks and sudden death. Researchers put the risk of developing clots at about 1 in 200-500 people.
Area cardiologists said they've found blood clots in the drug-coated stents of patients who survived heart attacks. And they can only presume that some others have died from the complication as well. Without autopsies, they can't know for sure.
Rapid escalation of use of the devices has only added to the alarm. Since they went on the market four years ago, drug-coated stents have far surpassed bare metal, becoming the stent of choice in 80-90 percent of all cases.
''It's a huge amount,'' local cardiologist Bryan Kluck acknowledged. At Lehigh Valley Hospital-Cedar Crest, where Kluck practices, cardiologists inserted the devices in about 1,700 patients last year. Over the same time at St. Luke's Hospital-Fountain Hill, about 1,000 patients received one or more drug-coated stents. Another 500 or so received the devices at Easton Hospital in Wilson.
In response to the findings, the American Heart Association, American College of Cardiology and other medical groups in early January recommended that most patients with drug-coated stents remain on anti-clotting medicines, such as the prescription drug Plavix, and aspirin, for at least a year, possibly indefinitely.
Experts believe continued use of anti-clotting medicines is the best recourse because research shows that patients who stayed on the drugs for a year fared the best among those studied. The 3-5 percent increased risk of blood clots occurred primarily among patients who stopped taking the medicines after six months.
Patients were supposed to stay on the pills for one to six months, depending on the type of stent used. However, one study showed the average time patients took the blood-thinners was 45 days.
''The increased risk [of blood clots] is very small and likely to be overcome if patients stay on anti-clotting medicines,'' noted Dr. Deepak Bhatt, a cardiologist and researcher at the Cleveland Clinic, which analyzed 14 studies involving drug-coated stents.
Promising, but not perfect
Two brands of drug-coated stents are used in the United States: Taxus by Boston Scientific Corp. and Cypher by Johnson & Johnson's Cordis Corp.
Placed inside a blocked coronary artery on the end of a deflated balloon, the stents are locked in place when the balloon is inflated. They act as a buttress to keep fatty deposits pinned against the artery wall. They restore blood flow to patients in the throes of a heart attack or who have blockages.
When they first came on the market, the drug-coated stents were recommended only for patients at low risk, such as those with small blockages in single vessels. But because early results with such patients looked so good, doctors used them in more common and complicated cases and in sicker patients.
Doctors had hints of a clotting problem from earlier studies, but it wasn't until the release of more conclusive data in December, much of it produced by the Duke Clinical Research Institute in Durham, N.C., that concern reached a critical level.
A rare summit of international experts called days later by the U.S. Food and Drug Administration produced the recommendation that patients remain on anti-clotting medication for a year or more.
But Dr. Robert A. Harrington, a professor of medicine in the division of cardiology and director of Duke's Clinical Research Institute, said the recommendation puts doctors and patients in another predicament.
''Are we committing millions of patients to lifelong [anti-clotting medicine] with its attendant costs and risks?'' he asks in an editorial about the blood-clot problems in a December issue of the Journal of the American College of Cardiology.
Plavix generic name clopidogrel and other blood-thinners can cause life-threatening internal bleeding in some patients, such as those with ulcers. It also has been shown to be no better than low-cost aspirin at preventing a first heart attack.
The Cleveland Clinic's Bhatt, however, doesn't think the side-effects of blood thinners are reason enough not to continue using drug-coated stents.
''Everything has risks,'' he said.
Weighing the risks
Some patients were so upset by the research that they asked that the stents be removed something doctors generally don't do, considering it much riskier than leaving the mesh tubes in place.
Cardiologists hope they can quickly learn which patients, beyond the low-risk, are best suited to drug-coated stents from patient registries and continued research. Or that the next generation of stents won't cause blood clots. In the works are stents with different coatings and others made to dissolve over time.
Until they have more answers, local and national specialists are extending the use of anti-clotting medicine. They also are being more selective in using drug-coated stents, perhaps precluding patients with long blockages or blockages that extend beyond one artery, persons with diabetes, persons scheduled for lung or colon cancer surgery or persons who have trouble keeping up pill regimens.
''There was a time that I'd try any case I could to use drug-coated stents,'' said Dr. Gary Costacurta, chief of cardiology at Easton Hospital in Wilson.
Now, Costacurta said, he may use bare-metal stents for patients with long blockages or for patients with blood vessels that are large in diameter.
LVH's Kluck said being more selective may not be so easy especially in the emergency room.
About 20 percent of the patients who receive stents arrive in the ER with chest pains and signs of imminent danger to the heart. It's a scenario in which seconds can make a difference, he said, in how much damage occurs to the heart and whether or not the patient lives.
Such cases leave little time for a full patient history, Kluck said. What medicines the patient had been taking or stopped taking and whether they have had bleeding problems in the past might not be known. ''It's not clear if plain stents are better than drug-coated'' for such patients, he said. ''We must probe deeper to know.''
Dr. Peter Puleo, a cardiologist and medical director of the catheterization laboratory at St. Luke's Hospital in Fountain Hill, said he started telling his patients to stay on anti-clotting medicines for two years when he read early studies suggesting a problem.
Puleo said he uses bare-metal stents on patients with long blockages or larger blood vessels. He said he is less worried about patients bleeding from blood-thinners than he is about heart attack and death from blood clots. ''Death from internal bleeding is even more unusual than late-term thrombosis,'' Puleo said, using another term for blood clots. ''In cardiology, more people clot than bleed to death.''
''It makes people nervous about continuing [on the medicines], but you can get through it,'' Puleo said.
Dr. J. Patrick Kleaveland, medical director of the catheterization laboratory at LVH and co-director of the lab at Grand View Hospital in West Rockhill Township, Bucks County, said drug-coated stents are still safe and effective in reducing restenosis for patients with simple, straight-forward blockages.
Patients at higher risk may still benefit as well, Kleaveland said, if they can stay on anti-clotting medicines for at least a year without uncontrolled bleeding. ''The patients I've seen with the most devastating problems are those who stopped taking their medicines prematurely,'' he said.
Reasons patients stop taking anti-clotting medication range from not being able to afford the pills, which cost $3-$4 a piece, to not feeling well on them or having difficulty keeping up with the regimen.
But cardiologists warn that stopping, even for a few days, could prove fatal if the body throws blood clots at the braced vessels.
''The first sign of trouble could be the total blockage of a stent, artery and blood flow,'' Kluck said. In other words, a sudden, massive heart attack.
Lehigh County Judge Edward Reibman stopped taking his prescription blood-thinner months after receiving a drug-coated stent in 2005. He counts himself lucky he didn't develop blood clots.
''When I had the stent put in, I was prescribed Plavix and aspirin, but I felt lousy on them,'' Reibman said, remembering muscle and bone pain.
He stopped the Plavix, switched to another anti-clotting drug and after a few months stopped that, too. But he continued taking a baby aspirin a day.
At a checkup in December, when news broke of the risk of blood clots, Reibman's doctor told him to resume the Plavix.
The judge wonders what new risks will come with the prescription medicine, but said he isn't judging prior decisions.
''Everyone thought the stents were fine. No one knew about this late stent [blood-clotting] problem then,'' he said. ''You make decisions with the best information you have at the time, and as science develops, you learn more and hopefully make more decisions.''
Monday, February 26, 2007
Tuesday, February 13, 2007
What's Up With Stents, Docs?
It's not often that the New England Journal of Medicine devotes most of its editorial content to a single subject and releases the information early online. That's exactly what it did Monday with a series of five studies and several commentaries on drug-eluting coronary stents. As the editors explained, "Our motivation is the recent concern that the implantation of drug-eluting stents, as compared with bare-metal stents, may be associated with a small increased risk of late stent thrombosis, a potentially fatal complication."
Drug-eluting stents were hailed as a "breakthrough technology" in 2003 and 2004, when the FDA approved the Cypher and Taxus stents, respectively. Like the bare-metal stents that preceded them, these tiny wire-mesh scaffolds were designed to prop open narrowed blood vessels (a problem known as stenosis), reducing the chest pain known as angina. Unlike bare-metal stents, however, the Cypher and Taxus devices were coated with drugs, the purpose of which was to prevent arterial cells from multiplying rapidly and narrowing the blood vessels again, a process known as "restenosis."
Drug-eluting stents caught on rapidly. By the end of 2004, they were used in 80-90 percent of stenting procedures. (Several million have now been implanted worldwide.) But concerns about their safety began to surface in the fall of 2005 and came to a head in March 2006, when a large population study in Sweden suggested that, between 7 and 18 months after implantation, patients with drug-eluting stents had higher rates of so-called stent thrombosis, in which a blood clot forms on exposed metalheart attacks an event often associated with acute heart attacks and sudden death. (An animation illustrating both restenosis and stent thrombosis is available at www.nejm.org.) These concerns prompted the FDA to convene a panel of experts in December to sift through the available evidence.
The new studies give more detailed versions of the evidence presented at the FDA in December. Unfortunately, a clear conclusion is still not readily available. "You could write whatever headline you wanted," says Dr. William Maisel of Beth Israel Deaconess Medical Center in Boston, who chaired the FDA panel and wrote one of the overview papers in the journal. "You could write that drug-eluting stents and bare-metal stents are equally safe [the conclusion of a study headed by Christian Spaulding in France]. Or you could write that there was more stent thrombosis after a year with drug-eluting stents, but no significant differences in overall rates of death and heart attack at four years [the conclusion of another paper by Gregg Stone at Columbia University]." Or, frankly, you could write that there was not only more stent thrombosis after six months with drug-eluting stents, but also death rates 18 to 32 percent higher three years afterwards, as indicated in the Swedish study.
How could the papers reach such different conclusions? The formal studies that led to FDA approval longer, follow-up versions of which constitute four of the five studies in the New England Journal enrolled only patients with the simplest, least complicated cases of arterial stenosis. When the FDA granted approval for drug-eluting stents, it was for use in patients like these. But once the devices were approved, doctors started using them in patients with more complex problems, too, such as longer lesions and problems in multiple vessels. The Swedish registry included these "real-world" patients, not just the ideal candidates in the approval trials.
What's a prospective patient to do? If you're thinking about getting a stent, here are three points to consider:
First, almost everyone seems to agree that drug-eluting stents lead to a slightly greater risk of stent thrombosis six months or more after implantation of the device. That's not surprising. Because the arterial lining doesn't grow back as quickly as with bare-metal stents, the metal mesh is exposed for longer, presenting a rough surface on which clots can form. Even Dr. Donald Baim, chief medical and scientific officer of Boston Scientific, which makes the Taxus stent, agreed with the point in an audio interview posted on the New England Journal's Web site. To compensate for the increased risk, the FDA panel recommended that patients stay on blood-thinning agents like aspirin and Plavix for at least 12 months afterwards an increase from the previous recommendation of 3-6 months. In addition, recipients should not undergo elective surgery during that time.
Second, it's important to realize that stents are mainly effective for relief of angina. There's very little evidence that they prevent heart attacks or reduce deaths, except when implanted during a heart attack. That's because most heart attacks don't come from narrowed arteries, but from ruptured plaque, around which massive clots form. So if you suffer from angina and want an improved quality of life, stents are very likely to help. If it's a heart attack you're trying to prevent, then it's not clear how great the benefit may be. (In the long run, some doctors suggest that a better option for preventing heart attacks may be aggressive drug therapy for high cholesterol and blood pressure. It's logical that drugs might help more, since they affect the entire cardiovascular system, not just a single artery. We'll know better next month, when a large trial comparing stents-plus-drugs against drug therapy alone will be unveiled at the American College of Cardiology meeting.)
Third, says Maisel, despite the uncertainties, drug-eluting stents have been an important advance in the management of coronary artery disease. They clearly reduce the occurrence of restenosis and hence the need for repeat procedures. Patients with simple obstructions in coronary arteries the patients for whom the devices were approved will likely do well with them. "But there's no free lunch," he warns. Anti-clotting therapy is important. For patients with more complicated cases, the equation is still uncertain.
Drug-eluting stents were hailed as a "breakthrough technology" in 2003 and 2004, when the FDA approved the Cypher and Taxus stents, respectively. Like the bare-metal stents that preceded them, these tiny wire-mesh scaffolds were designed to prop open narrowed blood vessels (a problem known as stenosis), reducing the chest pain known as angina. Unlike bare-metal stents, however, the Cypher and Taxus devices were coated with drugs, the purpose of which was to prevent arterial cells from multiplying rapidly and narrowing the blood vessels again, a process known as "restenosis."
Drug-eluting stents caught on rapidly. By the end of 2004, they were used in 80-90 percent of stenting procedures. (Several million have now been implanted worldwide.) But concerns about their safety began to surface in the fall of 2005 and came to a head in March 2006, when a large population study in Sweden suggested that, between 7 and 18 months after implantation, patients with drug-eluting stents had higher rates of so-called stent thrombosis, in which a blood clot forms on exposed metalheart attacks an event often associated with acute heart attacks and sudden death. (An animation illustrating both restenosis and stent thrombosis is available at www.nejm.org.) These concerns prompted the FDA to convene a panel of experts in December to sift through the available evidence.
The new studies give more detailed versions of the evidence presented at the FDA in December. Unfortunately, a clear conclusion is still not readily available. "You could write whatever headline you wanted," says Dr. William Maisel of Beth Israel Deaconess Medical Center in Boston, who chaired the FDA panel and wrote one of the overview papers in the journal. "You could write that drug-eluting stents and bare-metal stents are equally safe [the conclusion of a study headed by Christian Spaulding in France]. Or you could write that there was more stent thrombosis after a year with drug-eluting stents, but no significant differences in overall rates of death and heart attack at four years [the conclusion of another paper by Gregg Stone at Columbia University]." Or, frankly, you could write that there was not only more stent thrombosis after six months with drug-eluting stents, but also death rates 18 to 32 percent higher three years afterwards, as indicated in the Swedish study.
How could the papers reach such different conclusions? The formal studies that led to FDA approval longer, follow-up versions of which constitute four of the five studies in the New England Journal enrolled only patients with the simplest, least complicated cases of arterial stenosis. When the FDA granted approval for drug-eluting stents, it was for use in patients like these. But once the devices were approved, doctors started using them in patients with more complex problems, too, such as longer lesions and problems in multiple vessels. The Swedish registry included these "real-world" patients, not just the ideal candidates in the approval trials.
What's a prospective patient to do? If you're thinking about getting a stent, here are three points to consider:
First, almost everyone seems to agree that drug-eluting stents lead to a slightly greater risk of stent thrombosis six months or more after implantation of the device. That's not surprising. Because the arterial lining doesn't grow back as quickly as with bare-metal stents, the metal mesh is exposed for longer, presenting a rough surface on which clots can form. Even Dr. Donald Baim, chief medical and scientific officer of Boston Scientific, which makes the Taxus stent, agreed with the point in an audio interview posted on the New England Journal's Web site. To compensate for the increased risk, the FDA panel recommended that patients stay on blood-thinning agents like aspirin and Plavix for at least 12 months afterwards an increase from the previous recommendation of 3-6 months. In addition, recipients should not undergo elective surgery during that time.
Second, it's important to realize that stents are mainly effective for relief of angina. There's very little evidence that they prevent heart attacks or reduce deaths, except when implanted during a heart attack. That's because most heart attacks don't come from narrowed arteries, but from ruptured plaque, around which massive clots form. So if you suffer from angina and want an improved quality of life, stents are very likely to help. If it's a heart attack you're trying to prevent, then it's not clear how great the benefit may be. (In the long run, some doctors suggest that a better option for preventing heart attacks may be aggressive drug therapy for high cholesterol and blood pressure. It's logical that drugs might help more, since they affect the entire cardiovascular system, not just a single artery. We'll know better next month, when a large trial comparing stents-plus-drugs against drug therapy alone will be unveiled at the American College of Cardiology meeting.)
Third, says Maisel, despite the uncertainties, drug-eluting stents have been an important advance in the management of coronary artery disease. They clearly reduce the occurrence of restenosis and hence the need for repeat procedures. Patients with simple obstructions in coronary arteries the patients for whom the devices were approved will likely do well with them. "But there's no free lunch," he warns. Anti-clotting therapy is important. For patients with more complicated cases, the equation is still uncertain.
Drug-coated stents don't cut risk of heart attacks
The most exhaustive studies yet published on drug-coated stents show that the widely used heart devices are no better at preventing heart attacks and death than the older, cheaper devices they replaced, and in some cases may be slightly worse.
Since their introduction in 2003, the tiny wire tubes, about the size of a pen spring, have become fastest-selling medical devices in history, used in millions of people worldwide. They have been a boon to Boston Scientific Corp. of Natick, the largest life-science company in Massachusetts and one of the world's two major stent manufacturers.
However, safety concerns have emerged in the past year because drug-coated stents appear to carry a higher long-term risk of blood clots forming in the arteries that nourish the heart.
A series of studies released today by the New England Journal of Medicine showed that drug-coated stents carried one clear benefit: patients who receive them are less likely to return to the hospital for a repeat heart-clearing procedure.
Viewed over the long term, however, the stents did not improve patients' survival rates. And when Swedish doctors examined a computer registry of every Swedish stent patient for the years 2003 and 2004 nearly 20,000 people they found that patients with drug-coated stents were slightly more likely to die than those with bare-metal ones.
The information published today has been presented piecemeal at conferences and meetings over the past several months, most prominently at an expert panel convened in December by the Food and Drug Administration to discuss the long-term safety of the devices. But until now it had not yet appeared in any of the peer-reviewed journals widely read by doctors.
Dr. William Maisel, a cardiologist at Beth Israel Deaconess Medical Center in Boston who chairs the FDA's panel on cardiovascular devices, said the new studies would likely push doctors to be more cautious about using drug-coated stents. "The decision to put in a drug-eluting stent is now a decision, where before it was used in almost any case," he said.
Sales figures suggest doctors already are being more conservative about the use of drug-coated stents. Several months ago, many hospitals reported doctors were choosing drug-coated stents in as many as 90 percent of all procedures. A recent hospital survey suggested that number had dropped to 72 percent. In other countries, where drug-coated stents were never as widely adopted, the rates are lower still.
The drop in usage has triggered a stock slide for Boston Scientific, which depends heavily on the profits from drug-coated stents.
Stents are used in coronary angioplasties, a common artery-clearing procedure that has replaced bypass surgery for many patients as a way to restore blood flow to the heart. Typically patients receive one or more stents to keep cleared arteries open. The stent implant is permanent, sealing into the artery wall.
Drug-coated versions cost more than $2000, on average. Bare-metal stents typically cost $700. In its early trials, the drug-coated version clearly helped reduce the rate at which the arteries re-clogged. But as time has passed, long-term data show higher risks. The reasons are not conclusively known, although small studies on autopsied arteries suggest that the drug coating appears to impede normal healing of the artery wall.
Patients can minimize the risk of blood clots by taking aspirin and the blood-thinning medication Plavix, although doctors and the FDA have not reached consensus on how long the medicine should be prescribed.
Four of the articles published today are examinations of long-term data from the so-called "pivotal trials," the original stent studies sponsored by manufacturers. Overall, the articles found drug-coated stents were roughly as safe as bare-metal stents for the first year after the procedure, and helped patients avoid repeat procedures. Starting a year after the procedure, however, patients with drug-coated stents could expect a slightly higher risk of dangerous coronary blood clots. Overall heart attacks and death rates were roughly equivalent for patients with the two types of stents.
But those studies were limited to patients with relatively simple angioplasty problems. More than half of angioplasty heart patients in the US have more complex problems and it remains unclear whether they can count on the same results. The Swedish study, which analyzed a so-called "real-world" registry of patients, included a broader mixture of patients and found patients with drug-coated stents had an 18 percent higher risk of death than those with bare-metal stents.
In a statement, Boston Scientific said today that most of the study results confirmed its findings that drug-coated stents are safe and effective when used as approved by the FDA. A company executive singled out the Swedish study as "far from definitive" because it was an uncontrolled registry of patients rather than a randomized clinical trial.
Both Boston Scientific and Johnson & Johnson, the other major stent maker, are sponsoring further trials to assess the safety and effectiveness of stents in more complex patients.
Dr. Steven Nissen , chairman of cardiovascular medicine at the Cleveland Clinic and president of the American College of Cardiology, said the new papers highlight a "knowledge gap" in how stents really affect patients. "Even though drug-eluting stents have been implanted in millions of patients, they've only been studied in a few thousand," he said.
Nissen and Maisel said that the new results also point to a flaw in the system for distributing information about medical devices. Under current rules, companies control the data that emerges from studies they sponsor. After the clotting controversy erupted at medical meetings this year, both major stentmakers, Boston Scientific and Johnson & Johnson, released their data to independent researchers.
"It's not enough to collect that information," said Maisel. "It needs to be collected and shared."
Since their introduction in 2003, the tiny wire tubes, about the size of a pen spring, have become fastest-selling medical devices in history, used in millions of people worldwide. They have been a boon to Boston Scientific Corp. of Natick, the largest life-science company in Massachusetts and one of the world's two major stent manufacturers.
However, safety concerns have emerged in the past year because drug-coated stents appear to carry a higher long-term risk of blood clots forming in the arteries that nourish the heart.
A series of studies released today by the New England Journal of Medicine showed that drug-coated stents carried one clear benefit: patients who receive them are less likely to return to the hospital for a repeat heart-clearing procedure.
Viewed over the long term, however, the stents did not improve patients' survival rates. And when Swedish doctors examined a computer registry of every Swedish stent patient for the years 2003 and 2004 nearly 20,000 people they found that patients with drug-coated stents were slightly more likely to die than those with bare-metal ones.
The information published today has been presented piecemeal at conferences and meetings over the past several months, most prominently at an expert panel convened in December by the Food and Drug Administration to discuss the long-term safety of the devices. But until now it had not yet appeared in any of the peer-reviewed journals widely read by doctors.
Dr. William Maisel, a cardiologist at Beth Israel Deaconess Medical Center in Boston who chairs the FDA's panel on cardiovascular devices, said the new studies would likely push doctors to be more cautious about using drug-coated stents. "The decision to put in a drug-eluting stent is now a decision, where before it was used in almost any case," he said.
Sales figures suggest doctors already are being more conservative about the use of drug-coated stents. Several months ago, many hospitals reported doctors were choosing drug-coated stents in as many as 90 percent of all procedures. A recent hospital survey suggested that number had dropped to 72 percent. In other countries, where drug-coated stents were never as widely adopted, the rates are lower still.
The drop in usage has triggered a stock slide for Boston Scientific, which depends heavily on the profits from drug-coated stents.
Stents are used in coronary angioplasties, a common artery-clearing procedure that has replaced bypass surgery for many patients as a way to restore blood flow to the heart. Typically patients receive one or more stents to keep cleared arteries open. The stent implant is permanent, sealing into the artery wall.
Drug-coated versions cost more than $2000, on average. Bare-metal stents typically cost $700. In its early trials, the drug-coated version clearly helped reduce the rate at which the arteries re-clogged. But as time has passed, long-term data show higher risks. The reasons are not conclusively known, although small studies on autopsied arteries suggest that the drug coating appears to impede normal healing of the artery wall.
Patients can minimize the risk of blood clots by taking aspirin and the blood-thinning medication Plavix, although doctors and the FDA have not reached consensus on how long the medicine should be prescribed.
Four of the articles published today are examinations of long-term data from the so-called "pivotal trials," the original stent studies sponsored by manufacturers. Overall, the articles found drug-coated stents were roughly as safe as bare-metal stents for the first year after the procedure, and helped patients avoid repeat procedures. Starting a year after the procedure, however, patients with drug-coated stents could expect a slightly higher risk of dangerous coronary blood clots. Overall heart attacks and death rates were roughly equivalent for patients with the two types of stents.
But those studies were limited to patients with relatively simple angioplasty problems. More than half of angioplasty heart patients in the US have more complex problems and it remains unclear whether they can count on the same results. The Swedish study, which analyzed a so-called "real-world" registry of patients, included a broader mixture of patients and found patients with drug-coated stents had an 18 percent higher risk of death than those with bare-metal stents.
In a statement, Boston Scientific said today that most of the study results confirmed its findings that drug-coated stents are safe and effective when used as approved by the FDA. A company executive singled out the Swedish study as "far from definitive" because it was an uncontrolled registry of patients rather than a randomized clinical trial.
Both Boston Scientific and Johnson & Johnson, the other major stent maker, are sponsoring further trials to assess the safety and effectiveness of stents in more complex patients.
Dr. Steven Nissen , chairman of cardiovascular medicine at the Cleveland Clinic and president of the American College of Cardiology, said the new papers highlight a "knowledge gap" in how stents really affect patients. "Even though drug-eluting stents have been implanted in millions of patients, they've only been studied in a few thousand," he said.
Nissen and Maisel said that the new results also point to a flaw in the system for distributing information about medical devices. Under current rules, companies control the data that emerges from studies they sponsor. After the clotting controversy erupted at medical meetings this year, both major stentmakers, Boston Scientific and Johnson & Johnson, released their data to independent researchers.
"It's not enough to collect that information," said Maisel. "It needs to be collected and shared."
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