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EXPEDITED PUBLICATION

Normal Stress-Only Versus Standard Stress/Rest Myocardial Perfusion Imaging

Similar Patient Mortality With Reduced Radiation Exposure

Su Min Chang, MD^_*, Faisal Nabi, MD^_*, Jiaqiong Xu, PhD, Umara Raza, MD^_* and John J. Mahmarian, MD^_*,_*

^_* Methodist DeBakey Heart and Vascular Center
Methodist Hospital Research Institute, The Methodist Hospital, Houston, Texas

Manuscript received August 12, 2009; revised manuscript received September 22, 2009, accepted September 28, 2009.

^_* Reprint requests and correspondence: Dr. John J. Mahmarian, Methodist DeBakey Heart and Vascular Center, 6550 Fannin Street, Suite 677, Houston, Texas 77030 (Email: jmahmarian{at}tmhs.org).

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