Quantitative Gated Single-Photon Emission Computed Tomography With <sup>99m</sup>Tc Sestamibi Predicts Major Cardiac Events in Elderly Patients With Known or Suspected Coronary Artery Disease

Abstract

BACKGROUND: Although electrocardiogram-gated single-photon emission computed tomography (SPECT) may be useful in risk stratification of elderly patients with coronary artery disease (CAD), few studies have prospectively evaluated its prognostic value in this patient population. METHODS AND RESULTS: A total of 175 patients aged 75 years or more with known or suspected CAD were prospectively evaluated by stress gated SPECT using a 20-segment model and an automatic functional analysis. Patients with acute coronary syndrome within the previous 3 months, and those who underwent coronary revascularization within 3 months after the SPECT study were excluded. Outcome assessment included prespecified cardiac events and noncardiac deaths. During a mean follow-up of 3.4 years, there were 18 cardiac events: 2 cardiac deaths, 1 nonfatal myocardial infarction, 3 coronary artery bypass grafting, 5 percutaneous coronary interventions, 1 unstable angina, 4 heart failures, and 2 malignant arrhythmias. Kaplan-Meier survival estimation indicated an event-free survival rate of 98.1% at 3 years in patients without myocardial ischemia, but 79.9% in those with ischemia as documented by gated SPECT (p=0.0001). Multivariate analysis using the Cox proportional hazard model demonstrated that stress-induced myocardial ischemia was the only independent predictor for subsequent cardiac events (p<0.01). CONCLUSIONS: Stress gated SPECT predicts cardiac events in patients aged 75 years or more with known or suspected CAD and may have a role in risk stratification of this patient population.