Ischemia on stress testing is not associated with increased mortality risk in women

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After more than eight years of follow-up, women with signs and symptoms of ischemia and nonobstructive coronary artery disease had a 2.84-fold increased risk of death if they had prior infarct compared with if they had a nonischemic stress test, according to an analysis of a multicenter study.

The researchers added that ischemia on stress testing was not associated with an increased mortality risk in this patient population.

Lead researcher Tara L. Sedlak, MD, of Vancouver General Hospital in Canada, and colleagues published their results online in  JAMA Cardiology on May 11.

The researchers analyzed 936 women who underwent coronary angiography for suspected myocardial ischemia and enrolled in the Women’s Ischemia Syndrome Evaluation study from 1996 to 2000. The study took place at the University of Pittsburgh Medical Center, Allegheny County General Hospital in Pittsburgh, the University of Florida in Gainesville and the University of Alabama at Birmingham.

Of the women, 347 had nonobstructive coronary artery disease. They were categorized into ischemic, nonischemic or prior infarct groups.

The researchers defined ischemia as an exercise stress test with at least 1 mm of horizontal or downsloping ST segment depression in two or more contiguous leads during exercise; a dipyridamole stress technetium Tc 99m sestamibi with at least mild reversible defect; or a dobutamine stress echocardiography with at least 1 of 16 segments with stress-induced hypokinesis or akinesis.

They defined prior infarct as a technetium Tc 99m sestamibi with at least mild irreversible defect; a dobutamine stress echocardiography with more than 1 of 16 segments with fixed hypokinesis or akinesis; resting electrocardiogram evidence of significant Q waves in two or more contiguous leads; or a history of MI.

At baseline, women in the ischemic group had lower rates of hyperlipidemia and statin use, while women in the prior infarct group had lower rates of premature coronary artery disease.

During the follow-up period, there were 8 deaths in the ischemic group, 11 deaths in the nonischemic group and 12 deaths in the prior infarct group.

After adjusting for coronary artery severity scores, women with prior infarct had a significantly worse prognosis compared with women with a nonischemic stress test. However, the prognosis did not differ between the ischemic and nonischemic groups.

“Our results may not be generalizable to nonangiographic populations of women or to men,” the researchers said. “A second limitation is that our classification of women is based on a mixture of stress testing results with different sensitivity and specificity for ischemia and/or infarct. Our findings underscore the need for heightened recognition of an adverse event profile in these women.”