Stress echo identifies women at highest risk for CAD

Stress echo identifies women at highest risk for CAD

Seattle, Washington - Women who are already at high risk of coronary artery disease can be further stratified into low- and high-risk groups by the use of stress echo, a new study shows [1]. Senior author Dr Farooq A Chaudry (St Luke's-Roosevelt Hospital Center, New York) is to present the findings at the American Society of Echocardiography Scientific Sessions this weekend.

"We took women who were high risk based on clinical factors—such as a family history of CAD, diabetes, or prior MI—and found that those with an abnormal stress echo had a three-times-higher subsequent risk of MI and death than those who recorded a normal stress echo," Chaudry told heartwire.

Chaudry says stress echo—where echocardiography is performed immediately before and immediately after an exercise or pharmacological stress test—is "much more specific" than a 12-lead ECG. It also has advantages over nuclear imaging, another technique commonly employed by echocardiographers, he says.


Women with CAD have atypical presentation

One in three deaths in the US in women is caused by heart disease, compared with one in 30 due to breast cancer, Chaudry explained. However, women with CAD often have atypical presentation, making it difficult to see any problems clearly on ECG.

He and his team evaluated 447 women (mean age 65 years) with a high possibility of CAD—either they had had a prior event or intervention or were deemed to have a pretest likelihood of >85%—who were referred for stress echo (77% with dobutamine).

An abnormal stress echo was defined as one showing either scar or stress-induced ischemia. Follow-up for confirmed MI and death (n=44) was for a mean of 2.6 years.

Among the 447 women, 207 (47%) had an abnormal stress echo, and they had an event rate of 6.1% per year vs 1.8% per year in women with a normal stress echo.


Stress echo: More specific than nuclear testing

Chaudry says stress echo has a number of advantages over nuclear imaging. It is safer for women of reproductive age and no IV is required if conducting an exercise stress test (unless visualization is difficult, in which case an ultrasound image-enhancing agent is used, which needs to be injected into a vein).

Stress echo is also more specific than nuclear testing in that it can pinpoint the exact area of ischemia, he notes. And other anatomical and valvular abnormalities can be seen that are not picked up with nuclear testing. However, nuclear testing is more sensitive, he acknowledged.

He said that institutions tend to favor one technology over the other, often depending on whether they have a strong nuclear lab on site. Nuclear testing is popular in the US because reimbursement is better than for stress echo, he said. "In my institution, we perform about 4000 stress echoes a year and 1500 nuclear tests."

Source:

Bangalore S, Aziz E, Uretsky S, et al. Risk stratification and prognosis of high-risk females undergoing stress echocardiography. American Society of Echocardiography 18th Annual Scientific Sessions; June 16-20, 2007; Seattle, Washington. Presentation P1-20. Available here.