MONDAY, Jan. 17, 2005 (HealthDayNews) -- Women at risk for stroke may be treated too aggressively, a new study suggests.
The problem, said lead researcher Dr. Anthony Comerota, lies in the interpretation of a standard test called the duplex ultrasound. It is used to determine when surgery or stenting -- inserting mesh tubes to prop open arteries -- is warranted to prevent a stroke.
"Duplex ultrasound involves taking ultrasound images of blood vessels and measurement of the velocities within the blood vessels," said Comerota, director of the Jobst Vascular Center in Toledo, Ohio.
"The criteria on which we based our interpretation of the test is the speed of the blood flowing through the carotid arteries (the two vessels in the neck that send blood to the brain)," he added.
The speed of the blood is believed to reflect the status of vessel narrowing, with faster-flowing blood typically meaning the vessel has narrowed due to plaque buildup, a major cause of stroke in these arteries. Experts compare it to a pipe being pinched. If you pinch it, the blood has to flow faster to get through.
When the duplex ultrasound test was being standardized, Comerota said, much of the research was performed at Veterans Administration hospitals, with mostly men as subjects.
Now, Comerota's research shows that "the velocities of blood flow in women [to begin with] are higher than the velocities of blood flow for men."
The study findings were to be presented Monday at the annual International Symposium on Endovascular Therapy in Miami Beach, Fla.
In persons without symptoms of vascular disease, a blockage of about 60 percent is reason to suggest a surgical procedure to remove the plaque or create a bypass around the plaque blockage, Comerota said.
But the finding that women's blood flows faster "means we ought to reevaluate our interpretation criteria because we may be over-diagnosing a lot of disease in these women," Comerota said.
In the study, Comerota used duplex ultrasound to analyze the carotid arteries in 328 men and 241 women and correlated the findings with an arteriogram, a test that can measure narrowing of the artery.
"When we looked at the arteriograms, we found less disease on the arteriogram in women than we expected based on the duplex results," Comerota said.
"With the same ultrasound finding, a man may be advised to have surgery, but a woman may not," he added.
According to the American Heart Association, someone dies from a stroke every 3.3 minutes, making it the third-leading cause of death in the United States.
Another expert, Dr. Barry T. Katzen, program director of the symposium and a clinical professor of radiology at the University of Miami School of Medicine, said the new study is important.
"One of the things this study found is that women's blood seems to be flowing faster to begin with, at least in the carotid artery, so the results of the ultrasound may not be the same for both genders."
As interesting as the study result is, Katzen added, however, that "I think we need to confirm this with other studies."
Katzen said Comerota suggested that women may not need surgery until the blockage is 80 percent or greater.
At his institution, "we actually believe that in patients who haven't had symptoms, they probably shouldn't have stents or surgery until they get to over 80 percent blockage," he said, regardless of gender.
Comerota said both women and men can do much to reduce stroke risk, such as not smoking and controlling blood pressure.
More information
To learn about stroke warning signs, visit the American Stroke Association.
