Recommendations for Noninvasive Testing in Women with Suspected Coronary Artery Disease (CAD)
For women with a normal resting electrocardiography (ECG) and good exercise tolerance, evidence supports the recommendation from the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for a routine exercise treadmill test as the initial test for the evaluation of suspected CAD. Combining parameters such as exercise capacity and heart rate changes with the traditional evaluation of ST-segment changes improves the prognostic accuracy of the exercise treadmill test, making it a cost-efficient modality to use in this group of women (see Figure 1 in the original guideline document).
The indications for cardiac imaging in symptomatic cohorts of women are summarized in Figure 2 in the original guideline document. Cardiac imaging is recommended for symptomatic women with established CAD. Current evidence and practice guidelines recommend cardiac imaging for women with suspected CAD with an abnormal resting 12-lead ECG. More widespread use may be justified, but data are insufficient to support the primary use of imaging tests in all female patients. Cardiac imaging is recommended for women with an indeterminate or intermediate-risk exercise ECG test, as well as those with an intermediate-risk Duke treadmill score.
Although not considered in the current ACC/AHA guidelines, diabetic women merit special consideration and are included in the present statement as candidates for cardiac imaging because they have a risk of cardiovascular death that is up to 8-fold higher than that of non-diabetic women. As outlined in Figure 2 in the original guideline document, additional candidates for cardiac imaging include other intermediate- to high-risk groups with functional impairment that are suitable for pharmacological stress. On the basis of a growing body of evidence, cardiac imaging via contemporary techniques of stress echocardiography or gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging provides accurate diagnostic and prognostic information for women with suspected ischemic symptoms. Additional special populations of women who also may be at risk include women with the metabolic syndrome and those with polycystic ovary syndrome, although definitive imaging evidence is not available.
On the basis of existing evidence, the asymptomatic woman with a calcium score >400 has an annualized risk of CAD death or myocardial infarction (MI) of approximately 2% and should be considered at high cardiac risk. This recommendation is supported by the recently published AHA guidelines on CAD prevention in women, which noted that a 2% risk of major adverse cardiac events places a patient at high risk. Thus, many experts advocate that women with significant subclinical atherosclerosis should be treated with secondary prevention goals, although definitive randomized trial evidence is not available.
Conclusion
A review of the data suggests that, as in men, women with suspected and known CAD can be accurately diagnosed and risk-stratified via contemporary cardiac imaging techniques. Despite this, an abundance of evidence still suggests that women at risk for CAD are less often referred for the appropriate diagnostic test than are men. The present approaches to diagnostic testing may require some variation when applied to women, and ongoing investigation is needed to fully appreciate the multifactorial role of reproductive hormones on the vascular system and diagnostic testing. Additional work also is needed to fully assimilate sex-specific issues into clinical guidelines and everyday clinical practice when appropriate. The data reviewed here, however, suggest that women benefit from risk stratification with commonly used noninvasive cardiac tests. Local expertise and availability should guide the selection of cardiac imaging techniques in women with suspected and known CAD who are candidates for cardiovascular screening.
