ACCELL: Does the treadmill test work in woment?

Research from the last decade has revealed gender-specific differences in the presentation, manifestation, and diagnosis of coronary heart disease (CHD). There are dear gender differences in mortality. Fully 64% of women (vs. 50% of men) who die suddenly from CHD did not have classic warning symptoms. Moreover, 38% of women (vs. 25% of men) die within 1 year following myocardial infarction. Early recognition of symptoms and accurate diagnosis of CHD are of great importance if proper treatment strategies are to be implemented that will reduce the number of women dying from CHD. Given the number of noninvasive testing options, such as stress nuclear imaging, stress echocardiography, computed tomographic angiography (CTA)/ electron beam CT and magnetic resonance imaging (MRI), is there still a role for treadmill testing using an exercise electrocardiogram (ECG)? This is an especially pertinent question for female patients given the much higher sensitivity and specificity of other contemporary techniques compared with stress ECG (Slide 1). The limitations to exercise ECG in women include: • Exertional symptoms are of low predictive value (compared with men, women have fewer classic" symptoms and a lower prevalence of CHD when they come to testing); • Shorter exercise durations affect diagnostic accuracy; and • High rates of "false positives" (∼30%) in women. Yet, in terms of improving diagnostic and prognostic accuracy for women, using treadmill scores can be valuable. The most common scoring system in use in the United States is the Duke Treadmill Score (DTS) (Slide 2). One large study of treadmill testing in 976 women demonstrated equivalent diagnostic and prognostic ability for DTS in women and men (n = 2,249). Like other studies, women who presented for chest pain evaluation had less coronary artery disease (CAD) and performed differently on the treadmill compared with men. Despite this, combining several standard measures available from exercise treadmill testing, Alexander et al. were able to accurately risk stratify both genders for the presence of disease and survival and DTS added information beyond clinical factors in both women and men. (It should be noted that while DTS predicts cardiac survival in younger patients, Kwok et al. reported in Journal of the American College of Cardiology that it is not predictive in patients 75 years or older.) The authors acknowledged that risk prediction of DTS for women should be interpreted within the context of lower pretest risk for both diagnostic and prognostic risk stratification. Indeed, the three treadmill risk categories of low, moderate, and high risk in men corresponded to very low, low, and moderate risk in women. In essence, owing to the lower prevalence of disease in women, a low-risk DTS was actually better at excluding CAD in women than in men. Although many low-risk men can be managed without additional invasive testing, this study suggests that it is also true for both low-and moderate-risk women. Alexander and colleagues concluded, "Therefore, renewed confidence in the initial use and interpretation of treadmill testing in women should be encouraged especially for the purpose of excluding coronary artery disease".