Post by jeffolie on Sept 8, 2011 9:28:20 GMT -6
Study Is Ended as a Stent Fails to Stop Strokes
September 7, 2011
A promising but expensive device to prop open blocked arteries in the brain in the hope of preventing disabling or fatal strokes failed in a rigorous study, researchers reported on Wednesday. Those who got the device actually had so many more strokes than those assigned to control risk factors, like blood pressure, cholesterol and diabetes, that the study was abruptly terminated.
The Food and Drug Administration approved the device six years ago on the basis of a humanitarian exemption, which did not require solid evidence that it would prevent strokes. Thousands of patients got the devices since then, according to the study’s lead researcher. The finding that the devices actually more than doubled the rate of stroke or death raised serious questions about whether the F.D.A.’s procedures for approving such a medical device ended up putting patients at risk.
The study comes just a month after an expert panel at the Institute of Medicine, a major scientific group, recommended that the F.D.A. replace its more usual regulatory system for devices because it failed to establish the safety and efficacy of less risky devices, like artificial hips, before licensing.
While neurologists were deeply disappointed by the study’s outcome, they also said it was better to find out that the treatment was, on balance, harmful before it became standard medical practice.
Larry Kessler, an expert on medical devices and a former director in the F.D.A.’s Center for Devices and Radiological Health, said that the humanitarian exemption made sense sometimes, but that the new study showed its dangers.
If the study’s findings hold up, Dr. Kessler said the approval of the brain stents “should be something the F.D.A. is very concerned about.” The agency, he added, has the authority to withdraw its approval.
Karen Riley, a spokeswoman for the F.D.A., said the agency was currently looking at the data. One issue, she said, is whether the patients in the new study were comparable to those for whom the device was approved.
Researchers said the device seemed as if it should work. Disabling or fatal strokes can be caused by brain arteries blocked by atherosclerosis, in much the same way that blocked coronary arteries cause heart attacks. So perhaps strokes might be prevented in much the same way.
That led Boston Scientific to make a small wire cage, a stent, to hold blocked brain arteries open, similar to the ones used to open blocked vessels leading to the heart. It was risky — brain arteries are fragile, and the brain, unlike the heart, is unforgiving of bleeding that can occur. It also is difficult to get a stent to the brain. Doctors must thread a catheter from up the groin, navigating a tortuous path to the delicate brain arteries.
According to the National Institute of Neurological Disorders and Stroke, at least 55,000 of the 795,000 strokes occurring each year are caused by blockages in small arteries in the brain.
The Food and Drug Administration approved the new stent in August 2005 for high-risk patients who failed medical management. It relied on a study with 45 patients. It was a registry study — one that had no control group that, for comparison, did not get the stent. The study found a 4.4 percent stroke rate in the first month, much better than expected without the device. But registry studies almost invariably report better results than studies with a comparison group, said Dr. Walter J. Koroshetz, deputy director of the National Institute of Neurological Disorders and Stroke.
Yet doctors, eager to help patients with dire prognoses, put the stents in thousands of patients, said Dr. Marc Chimowitz of the Medical College of South Carolina and the principal investigator of the new study. Private insurance often paid the more than $21,000 for the stent and its insertion in the brain artery, a price that did not include a stay in intensive care afterward. The average age of patients in the new study was about 60.
But Medicare paid only if patients were in research studies. Such studies include registry studies, but the restriction also allowed researchers to recruit patients for a study that randomly assigned them to receive the device and intensive medical management, a vigorous effort to control their risk factors, or to have intensive medical management alone. Patients in this study had just had a stroke or a near miss, a transient ischemic attack that involves stroke symptoms that clear up within 24 hours. Patients also had a brain artery that was 70 percent to 99 percent blocked. Their risk of another stroke in the same area of the brain in the next year was about 23 percent, even with medical treatment to reduce risk factors.
The study’s results, published online Wednesday in The New England Journal of Medicine, were sobering. Thirty three patients, or 14.7 percent, who got the stent had a stroke in the first month, and five died. Among those who had medical therapy, 13 patients, 5.8 percent, had strokes in the first month. One died, but not from a stroke.
The medical therapy group actually did better than expected, perhaps because they were prompted and hounded to get their risk factors under control and also, Dr. Chimowitz said, because they took two drugs to prevent clots, aspirin and clopidogrel, for 90 days.
“Quite frankly, the results were a surprise,” said Dr. Joseph Broderick, chairman of neurology at the University of Cincinnati College of Medicine.
Now, Dr. Koroshetz would like to complete a study of another desperate measure to save stroke patients — threading a catheter into the brain to fish out a blood clot blocking an artery. But with Medicare paying for that treatment whether or not patients are in research studies, “we are having a devil of a time recruiting patients” for the study, he said.
www.nytimes.com/2011/09/08/health/research/08stent.html
September 7, 2011
A promising but expensive device to prop open blocked arteries in the brain in the hope of preventing disabling or fatal strokes failed in a rigorous study, researchers reported on Wednesday. Those who got the device actually had so many more strokes than those assigned to control risk factors, like blood pressure, cholesterol and diabetes, that the study was abruptly terminated.
The Food and Drug Administration approved the device six years ago on the basis of a humanitarian exemption, which did not require solid evidence that it would prevent strokes. Thousands of patients got the devices since then, according to the study’s lead researcher. The finding that the devices actually more than doubled the rate of stroke or death raised serious questions about whether the F.D.A.’s procedures for approving such a medical device ended up putting patients at risk.
The study comes just a month after an expert panel at the Institute of Medicine, a major scientific group, recommended that the F.D.A. replace its more usual regulatory system for devices because it failed to establish the safety and efficacy of less risky devices, like artificial hips, before licensing.
While neurologists were deeply disappointed by the study’s outcome, they also said it was better to find out that the treatment was, on balance, harmful before it became standard medical practice.
Larry Kessler, an expert on medical devices and a former director in the F.D.A.’s Center for Devices and Radiological Health, said that the humanitarian exemption made sense sometimes, but that the new study showed its dangers.
If the study’s findings hold up, Dr. Kessler said the approval of the brain stents “should be something the F.D.A. is very concerned about.” The agency, he added, has the authority to withdraw its approval.
Karen Riley, a spokeswoman for the F.D.A., said the agency was currently looking at the data. One issue, she said, is whether the patients in the new study were comparable to those for whom the device was approved.
Researchers said the device seemed as if it should work. Disabling or fatal strokes can be caused by brain arteries blocked by atherosclerosis, in much the same way that blocked coronary arteries cause heart attacks. So perhaps strokes might be prevented in much the same way.
That led Boston Scientific to make a small wire cage, a stent, to hold blocked brain arteries open, similar to the ones used to open blocked vessels leading to the heart. It was risky — brain arteries are fragile, and the brain, unlike the heart, is unforgiving of bleeding that can occur. It also is difficult to get a stent to the brain. Doctors must thread a catheter from up the groin, navigating a tortuous path to the delicate brain arteries.
According to the National Institute of Neurological Disorders and Stroke, at least 55,000 of the 795,000 strokes occurring each year are caused by blockages in small arteries in the brain.
The Food and Drug Administration approved the new stent in August 2005 for high-risk patients who failed medical management. It relied on a study with 45 patients. It was a registry study — one that had no control group that, for comparison, did not get the stent. The study found a 4.4 percent stroke rate in the first month, much better than expected without the device. But registry studies almost invariably report better results than studies with a comparison group, said Dr. Walter J. Koroshetz, deputy director of the National Institute of Neurological Disorders and Stroke.
Yet doctors, eager to help patients with dire prognoses, put the stents in thousands of patients, said Dr. Marc Chimowitz of the Medical College of South Carolina and the principal investigator of the new study. Private insurance often paid the more than $21,000 for the stent and its insertion in the brain artery, a price that did not include a stay in intensive care afterward. The average age of patients in the new study was about 60.
But Medicare paid only if patients were in research studies. Such studies include registry studies, but the restriction also allowed researchers to recruit patients for a study that randomly assigned them to receive the device and intensive medical management, a vigorous effort to control their risk factors, or to have intensive medical management alone. Patients in this study had just had a stroke or a near miss, a transient ischemic attack that involves stroke symptoms that clear up within 24 hours. Patients also had a brain artery that was 70 percent to 99 percent blocked. Their risk of another stroke in the same area of the brain in the next year was about 23 percent, even with medical treatment to reduce risk factors.
The study’s results, published online Wednesday in The New England Journal of Medicine, were sobering. Thirty three patients, or 14.7 percent, who got the stent had a stroke in the first month, and five died. Among those who had medical therapy, 13 patients, 5.8 percent, had strokes in the first month. One died, but not from a stroke.
The medical therapy group actually did better than expected, perhaps because they were prompted and hounded to get their risk factors under control and also, Dr. Chimowitz said, because they took two drugs to prevent clots, aspirin and clopidogrel, for 90 days.
“Quite frankly, the results were a surprise,” said Dr. Joseph Broderick, chairman of neurology at the University of Cincinnati College of Medicine.
Now, Dr. Koroshetz would like to complete a study of another desperate measure to save stroke patients — threading a catheter into the brain to fish out a blood clot blocking an artery. But with Medicare paying for that treatment whether or not patients are in research studies, “we are having a devil of a time recruiting patients” for the study, he said.
www.nytimes.com/2011/09/08/health/research/08stent.html