Clinical Research
Cardiac Imaging
Normal Stress-Only Versus Standard Stress/Rest Myocardial Perfusion Imaging: Similar Patient Mortality With Reduced Radiation Exposure

https://doi.org/10.1016/j.jacc.2009.09.022Get rights and content
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Objectives

The aim of this study was to determine whether a normal stress-only single-photon emission computed tomographic myocardial perfusion tomography (SPECT) study confers the same prognosis as a normal SPECT on the basis of evaluation of stress and rest images.

Background

Current guidelines recommend stress and rest imaging to confirm that a SPECT study is normal.

Methods

We determined all-cause mortality in 16,854 consecutive patients who had a normal gated stress SPECT. Median follow-up was 4.5 years. A stress-only protocol was used in 8,034 patients (47.6%), whereas 8,820 (52.4%) had both stress and rest imaging.

Results

The overall unadjusted annual mortality rate in patients who had a normal SPECT with a stress-only protocol was lower than in those who required additional rest imaging (2.57% vs. 2.92%, p = 0.02). After adjustment for baseline clinical characteristics no significant differences in patient mortality were seen between the 2 imaging protocols, but the stress-only group received a 61% lower radiopharmaceutical dosage. Independent predictors of worse survival included increasing age, male sex, diabetes, history of coronary artery disease, and inability to exercise (all p < 0.001) but not the type of SPECT protocol used to image patients.

Conclusions

Patients determined to have a normal SPECT on the basis of stress imaging alone have a similar mortality rate as those who have a normal SPECT on the basis of evaluation of both stress and rest images. Our results support that additional rest imaging is not required in patients who have a normally appearing initial stress study. A significant reduction in radiation exposure can be achieved with such an approach.

Key Words

myocardial perfusion imaging
risk stratification

Abbreviations and Acronyms

BMI
body mass index
CAD
coronary artery disease
ECG
electrocardiogram
LV
left ventricular
LVEF
left ventricular ejection fraction
SPECT
single-photon emission computed tomography
Tc
technetium
TR
time ratio

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