Exercise stress testing in women: going back to the basics.

Marked reductions in cardiovascular mortality in women have occurred for the first time this decade as a result of advances in medical treatment, improvement in medical technology, and a greater focus on women and their cardiovascular risk.1 Nonetheless, cardiovascular disease remains the No. 1 cause of death for women in the United States, and more women die from cardiovascular disease than men every year.2 In addition, women with coronary artery disease (CAD) are more likely to have a poorer prognosis than men.1,3,4 Women who have an acute myocardial infarction have a higher mortality than their male counterparts, and women who have symptoms of angina or an abnormal stress test are less likely to be referred for further diagnostic testing.2,5–7 Given these gender differences in the evaluation of possible CAD symptoms and the higher mortality due to CAD in women, critical steps should be taken to identify women at the earliest stage of presentation so that appropriate therapeutic strategies can be implemented. Nonetheless, identifying women with coronary disease can be a diagnostic challenge. The prevalence of CAD in younger women is low, and women tend to present with symptoms and CAD at older ages as compared with men. In addition, women may present with more atypical symptoms.8 Women also have a lower prevalence of obstructive coronary disease, making diagnostic testing designed to detect focal areas of coronary stenosis less sensitive and specific in this population.9 Currently, exercise stress testing is the most commonly used method of diagnosing CAD in women,10–12 and the exercise stress ECG is the initial noninvasive study of choice in the diagnosis of CAD. Both the 2002 American Heart Association/American College of Cardiology (AHA/ACC) Guidelines for Exercise Testing13 and the 2005 Guidelines for the Role of Noninvasive Testing in the Clinical Evaluation of Women with Suspected Coronary Artery Disease14 recommend the exercise ECG as the first diagnostic test of choice in symptomatic, intermediate-risk women with a normal baseline ECG. Historically, exercise stress testing in women has been thought to have a decreased diagnostic accuracy because of a lower prevalence of CAD in women, but most early studies evaluating stress testing as a diagnostic tool were performed in almost exclusively male cohorts.15–25 Until recently, the representation of women in published studies was too small to determine any gender differences in test accuracy. The underrepresentation of women, as well as the bias in selection of women when included, may be the reason for the misconceptions regarding the value of exercise stress testing in women. Nonetheless, research on exercise stress testing in women has increased in the past decade, improving our understanding of the diagnostic and prognostic value of this modality in women. The purpose of this article is to review the literature regarding exercise stress testing in women, with a focus beyond ST-segment depression alone. It addition to interpretation of ECG changes with exercise, evaluation of exercise capacity, chronotropic index, heart rate (HR) recovery (HRR), blood pressure response, and Duke Treadmill Score (DTS) can be used to enhance the utility of exercise testing. The diagnostic and prognostic value of these non-ECG variables in women is reviewed, with a goal of highlighting the importance of exercise stress testing in women on the basis of the research available to date.