Stents to unclog arteries tied to bleeding events
Friday, August 26, 2011
By Kerry Grens
NEW YORK (Reuters Health) - A fresh look at medical records finds a newer technique used to remove blockages in the arteries that supply blood to the brain is tied to a greater chance of bleeding within the head than an older surgical procedure.
Researchers found hemorrhaging in the brain was roughly six times as likely in patients who underwent carotid artery stenting, which inserts a tube into the artery to clear the passage, as in patients who had an endarterectomy, a surgical procedure that scrapes the plaque from the artery.
The findings conflict with previous work showing that stenting appears to be as safe as surgically removing blockages in the artery (see Reuters report of February 26, 2010).
"We expected to see modest differences between the groups," said Dr. David Kallmes, senior author of the study and a professor of radiology at the Mayo Clinic in Rochester, Minnesota.
But the large gap between the stent group and the surgery group "was shocking to us and caused us to look at the data several times."
Kallmes and his colleagues took their data from a large national bank of medical records.
Among 215,000 cases of surgery to clear the artery and 13,000 stenting procedures, brain bleeds were rare, but Kallmes's group was still able to see a difference between the two approaches.
They split the records into two groups: one included patients who had symptoms of the plaque dislodging and going into the brain (which can cause a stroke), and the other group who did not have symptoms.
Forty-four out of every 1,000 people who had a stent inserted into their neck and who had symptoms experienced hemorrhaging. That compared to eight out of 1,000 in the group that received the surgery.
Of those patients who did not have symptoms, five out of every 1,000 who had a stent experienced bleeding, and 6 out of every 10,000 patients who had surgery also had a hemorrhage. Bleeding in the head after a stroke-preventing procedure was linked to a greater chance of dying while in the hospital and of being discharged to a rehabilitation or nursing facility, rather than home.
"It's not that we think stenting is not safe," said Dr. Robert McDonald, who led the study, "but there might be something here we need to investigate further -- why there's this increased risk."
Stents have been approved by the U.S. Food and Drug Administration (FDA) since 2004 as an alternative to surgery for preventing stroke in patients who were considered high risk. Earlier this year, the FDA expanded its approval of the device to all patients who would otherwise have surgery. Both procedures are controversial, however, and many doctors believe doing surgery or inserting stents in clogged arteries is too hazardous for symptom-free people at average risk.
"There is a very important story to be told about unnecessary carotid surgery and stenting in the U.S.," Dr. David Spence, a stroke prevention researcher at the University of Western Ontario in London, Canada, told Reuters Health last week.
According to his research, 90 percent of symptom-free patients who get surgery would be better off without it, he said in an email. Dr. Stanley L. Barnwell, the medical director of intervention neuroradiology at Oregon Health and Science University in Portland, said he's less convinced by the results of the new study than by earlier research showing stenting is just as safe as surgery. In an earlier experiment called the CREST trial, patients were randomly assigned to receive either of the procedures to clear up the plaque in their arteries.
This type of project set out in advance to control for differences between the patients and to carefully monitor their outcomes, whereas the current study is a look back on medical records from patients who were not necessarily part of a study.
"These large databases are very hard to pull out reliable data from," Barnwell, who was not involved in either study, told Reuters Health. Kallmes said the studies complement each other -- his study had more numbers and reflected real world practice, while the earlier trial was carefully controlled but limited in the number of patients involved.
"Maybe they give us bookends of the real rate of hemorrhage, and the truth lies somewhere in between," Kallmes said. In his study, published in the journal Stroke, Kallmes and his colleagues call for more research to explain why they saw such a big difference between the two procedures.
SOURCE: http://bit.ly/oU3yci, Stroke, online August 11, 2011.
NEW YORK (Reuters Health) - A fresh look at medical records finds a newer technique used to remove blockages in the arteries that supply blood to the brain is tied to a greater chance of bleeding within the head than an older surgical procedure.
Researchers found hemorrhaging in the brain was roughly six times as likely in patients who underwent carotid artery stenting, which inserts a tube into the artery to clear the passage, as in patients who had an endarterectomy, a surgical procedure that scrapes the plaque from the artery.
The findings conflict with previous work showing that stenting appears to be as safe as surgically removing blockages in the artery (see Reuters report of February 26, 2010).
"We expected to see modest differences between the groups," said Dr. David Kallmes, senior author of the study and a professor of radiology at the Mayo Clinic in Rochester, Minnesota.
But the large gap between the stent group and the surgery group "was shocking to us and caused us to look at the data several times."
Kallmes and his colleagues took their data from a large national bank of medical records.
Among 215,000 cases of surgery to clear the artery and 13,000 stenting procedures, brain bleeds were rare, but Kallmes's group was still able to see a difference between the two approaches.
They split the records into two groups: one included patients who had symptoms of the plaque dislodging and going into the brain (which can cause a stroke), and the other group who did not have symptoms.
Forty-four out of every 1,000 people who had a stent inserted into their neck and who had symptoms experienced hemorrhaging. That compared to eight out of 1,000 in the group that received the surgery.
Of those patients who did not have symptoms, five out of every 1,000 who had a stent experienced bleeding, and 6 out of every 10,000 patients who had surgery also had a hemorrhage. Bleeding in the head after a stroke-preventing procedure was linked to a greater chance of dying while in the hospital and of being discharged to a rehabilitation or nursing facility, rather than home.
"It's not that we think stenting is not safe," said Dr. Robert McDonald, who led the study, "but there might be something here we need to investigate further -- why there's this increased risk."
Stents have been approved by the U.S. Food and Drug Administration (FDA) since 2004 as an alternative to surgery for preventing stroke in patients who were considered high risk. Earlier this year, the FDA expanded its approval of the device to all patients who would otherwise have surgery. Both procedures are controversial, however, and many doctors believe doing surgery or inserting stents in clogged arteries is too hazardous for symptom-free people at average risk.
"There is a very important story to be told about unnecessary carotid surgery and stenting in the U.S.," Dr. David Spence, a stroke prevention researcher at the University of Western Ontario in London, Canada, told Reuters Health last week.
According to his research, 90 percent of symptom-free patients who get surgery would be better off without it, he said in an email. Dr. Stanley L. Barnwell, the medical director of intervention neuroradiology at Oregon Health and Science University in Portland, said he's less convinced by the results of the new study than by earlier research showing stenting is just as safe as surgery. In an earlier experiment called the CREST trial, patients were randomly assigned to receive either of the procedures to clear up the plaque in their arteries.
This type of project set out in advance to control for differences between the patients and to carefully monitor their outcomes, whereas the current study is a look back on medical records from patients who were not necessarily part of a study.
"These large databases are very hard to pull out reliable data from," Barnwell, who was not involved in either study, told Reuters Health. Kallmes said the studies complement each other -- his study had more numbers and reflected real world practice, while the earlier trial was carefully controlled but limited in the number of patients involved.
"Maybe they give us bookends of the real rate of hemorrhage, and the truth lies somewhere in between," Kallmes said. In his study, published in the journal Stroke, Kallmes and his colleagues call for more research to explain why they saw such a big difference between the two procedures.
SOURCE: http://bit.ly/oU3yci, Stroke, online August 11, 2011.
Reuters Health
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