Effective risk stratification using exercise myocardial perfusion SPECT in women: gender-related differences in prognostic nuclear testing.
OBJECTIVE
This study was designed to evaluate the incremental prognostic value over clinical and exercise variables of rest thallium-201/exercise technetium-99m sestamibi single-photon emission computed tomography (SPECT) in women compared with men and to determine whether this test can be used to effectively risk stratify patients of both genders.


BACKGROUND
To minimize the previously described gender-related bias in the evaluation of coronary artery disease in women, there is a need to identify a noninvasive testing strategy that is able to accurately and effectively risk stratify women.


METHODS
We identified 4,136 consecutive patients (2,742 men, 1,394 women) who underwent dual-isotope SPECT. The incremental value of nuclear testing was determined using both a stepwise Cox proportional hazards model and Kaplan-Meier survival analysis. Receiver operating characteristic curve analysis was performed 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 occurred in the men, and 31 myocardial infarctions and 14 cardiac deaths occurred in the women. Nuclear testing significantly stratified both men and women irrespective of their rest electrocardiogram. Cox proportional hazards analysis revealed that nuclear testing added incremental prognostic value in both men and women after inclusion of the most predictive clinical exercise variables (overall chi-square 89 in men vs. 120 in women, p < 0.005). Kaplan-Meier survival analysis demonstrated that nuclear testing further stratified men and women with both intermediate to high and low prescan likelihoods of coronary artery disease (p < 0.005 for all). Receiver operating characteristic curve analysis 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 < 0005). The odds ratio comparing event rates in patients with women than in men, suggesting superior stratification using nuclear testing in women.


CONCLUSIONS
Dual-isotope myocardial perfusion imaging yields incremental prognostic value in both men and women. This modality identifies low risk women and men equally well but relatively high risk women more accurately than relatively high risk men and, thus, is able to stratify women more effectively than men.
Hachamovitch
R
R
Department of Imaging (Division of Nuclear Medicine), Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
Berman
D S
DS
Kiat
H
H
Bairey
C N
CN
Cohen
I
I
Cabico
A
A
Friedman
J
J
Germano
G
G
Van Train
K F
KF
Diamond
G A
GA
D015982:Bias; D003327:Coronary Disease / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D016019:Survival Analysis; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon
D013794:Thallium Radioisotopes; D017256:Technetium Tc 99m Sestamibi