Invasive Stroke Prevention Risky for Women

Although doctors have been criticized for not treating cardiovascular disease as aggressively in women as in men, new data suggest that women may actually be treated too aggressively.

A standard test is used to assess when the risk of a stroke outweighs the risk of preventive treatments, which include surgery and nonsurgical placement of a stent. Usually, this test is interpreted in the same manner for both men and women. This leads to a potential overestimation of a woman's risk of stroke, researchers have found.

Duplex ultrasound, involving a Doppler probe, is the test most often used to assess carotid artery narrowing, which translates into the risk of stroke. This method measures how fast the blood is flowing through the artery. Fast blood implies the artery is narrowed, and the more quickly it is flowing, the worse the blockage will be. However, a women's blood tends to flow faster than men even when normal, which suggests the results should be interpreted differently for the two genders.

In a recent study, duplex ultrasound was used to analyze the most-diseased artery in 328 men and 241 women during a 10-year period. Each patient also had an arteriogram, which accurately measures the narrowing of the artery. Researchers found that blood flow in women was about 16% faster than in men on average.

"At our clinic, we treat men when duplex ultrasound shows they have a blockage of 60-70%, whereas for women, we're waiting until the duplex ultrasound suggests the blockage is about 80%,” noted Anthony Comerota, M.D., principal investigator in the study and clinical professor of surgery at the University of Michigan (Ann Arbor, USA).

According to Dr. Comerota, the difference in treatment risks and results is likely due to several factors. Women's blood vessels are smaller and less compliant than men's, making treatment riskier. Also, plaque is distributed differently in the carotid arteries of the two genders. Numerous studies have shown that using stents to open clogged leg arteries is less successful in women than in men.




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