EFFECTIVE RISK STRATIFICATION USING EXERCISE MYOCARDIAL PERFUSION SPECT IN WOMEN - GENDER-RELATED DIFFERENCES IN PROGNOSTIC NUCLEAR TESTING

Objectives. This study was designed to evaluate the incremental progno stic value over clinical and exercise variables of rest thallium-201/e xercise technetium-99m sestamibi single-photon emission computed tomog raphy (SPECT) in women compared with men and to determine whether this test can be used to effectively risk stratify patients of both gender s. Background. To minimize the previously described gender-related bia s in the evaluation of coronary artery disease in women, there is a ne ed to identify a noninvasive testing strategy that is able to accurate ly and effectively risk stratify women. Methods. We identified 4,136 c onsecutive patients (2,742 men, 1,394 women) who underwent dual-isotop e SPECT. The incremental value of nuclear testing was determined using both a stepwise Cox proportional hazards model and Kaplan-Meier survi val analysis. Receiver operating characteristic curve analysis was per formed to determine test discrimination for high risk patients in men and women.Results. The patient population was followed up for 20 +/- 5 months for events (cardiac death or nonfatal myocardial infarction). During this time, 63 myocardial infarctions and 32 cardiac deaths occu rred in the men, and 31 myocardial infarctions and 14 cardiac deaths o ccurred in the women. Nuclear testing significantly stratified both me n and women irrespective of their rest electrocardiogram. Cox proporti onal hazards analysis revealed that nuclear testing added incremental prognostic value in both men and women after inclusion of the most pre dictive clinical and exercise variables (overall chi-square 89 in men vs, 120 in women, p < 0.005). Kaplan-Meier survival analysis demonstra ted that nuclear testing further stratified men and women with both in termediate to high and low prescan likelihoods of coronary artery dise ase (p < 0.005 for all). Receiver operating characteristic curve analy sis demonstrated superior discrimination for the nuclear scan results in identifying high risk women than men (area under the curve: 0.84 +/ - 0.03 vs. 0.71 +/- 0.03 in men, p < 0.0005). The odds ratio comparing event rates in patients with abnormal versus those with normal scan r esults was greater in women than in men, suggesting superior stratific ation using nuclear testing in women. Conclusions. Dual-isotope myocar dial perfusion imaging yields incremental prognostic value in both men and women. This modality identifies low risk women and men equally we ll but relatively high risk women more accurately than relatively high risk men and, thus, is able to stratify women more effectively than m en.