CHICAGO – In women who present for evaluation of suspected coronary artery disease and who are at low to intermediate pretest risk, an exercise electrocardiogram is a better initial diagnostic strategy than is the popular combination of exercise ECG plus myocardial perfusion single-photon emission computed tomography imaging, according to the randomized WOMEN trial.
The 2-year follow-up in the WOMEN study showed that exercise ECG was equally effective as – and less costly than – exercise ECG plus myocardial perfusion SPECT, which until now has regularly been used in this setting, reported Leslee J. Shaw, Ph.D., at the annual scientific sessions of the American Heart Association.
"We believe that the clinical and health economic implications of this trial are potentially profound and may inform clinical practice guideline development and medical coverage decisions," declared Dr. Shaw, professor of medicine at Emory University, Atlanta.
The WOMEN (What Is the Optimal Method for Ischemia Evaluation in Women?) trial involved 772 women who presented with chest pain and/or other ischemic symptoms at 44 participating institutions and completed 2 years of prospective follow-up.
Half the women were 50 years old or older, and one-quarter were at least age 65. Participants had to be capable of achieving high levels of treadmill exercise as defined by minimal limitations on activities of daily living on the DASI (Duke Activity Status Index). Participating centers had to complete webinars to ensure they were using state-of-the-art testing procedures.
The primary study composite end point was the 2-year rate of death resulting from coronary disease; acute MI; or hospitalization for unstable angina or heart failure. Rates were similarly very low in both study arms, with a total of only 17 events in the entire population.
The secondary end point in WOMEN was angina-free status. Again, rates were similar in both groups (60% at 2 years in the exercise ECG group vs. 65% in the exercise ECG–plus-SPECT group).
The mean total cost over 2 years was $338 in the exercise ECG group, significantly less than the $643 with initial dual testing. Over the course of 2 years, 18% of patients in the initial ECG–only group underwent SPECT testing, and 9% of those randomized to dual testing underwent repeat SPECT imaging.
Two-thirds of participants had a negative exercise ECG and the rest had either an equivocal or abnormal study. In contrast, 91% of patients who were assigned to dual testing had a negative SPECT study, whereas 3% had a mildly abnormal scan and 6% had a moderately to severely abnormal scan.
Only 25 patients in each study arm underwent coronary angiography during the 2-year study period. Although exercise ECG testing had a lower sensitivity and specificity for angiographically confirmed CAD than did dual testing, the angiography rate was too low to allow any meaningful conclusions regarding diagnostic accuracy, according to Dr. Shaw.
An important study limitation was that the WOMEN trial enrolled relatively low-risk subjects, limiting the generalizability of the findings in higher-risk women. Nonetheless, the study indicates that an exercise ECG–first strategy is preferable in low-risk women because it results in more selective use of costly follow-up imaging tests, she said.
The WOMEN study was funded by an unrestricted grant from GE Healthcare. Dr. Shaw declared having no relevant financial relationships.