Prognostic Implications of Myocardial Perfusion Single-Photon Emission Computed Tomography in the Elderly

Background-The goal of this study was to assess the clinical value of stress myocardial perfusion scintigraphy (MPS) in elderly patients (>= 75 years of age). Methods and Results-We followed up 5200 elderly patients (41% exercise) after dual-isotope MPS over 2.8 +/- 1.7 years (362 cardiac deaths [CDs], 7.0%, 2.6%/y) and a subset with extended follow-up (684 patients for 6.2 +/- 2.9 years; 320 all-cause deaths). Survival modeling of CD revealed that both MPS-measured ischemia and fixed defect added incrementally to pre-MPS data in both adenosine and exercise stress patients. Modeling a subset with gated MPS (n = 2472) revealed that ejection fraction and perfusion data added incrementally to each other, further enhancing risk stratification. Unadjusted, annualized post-normal MPS CD rate was 1.3% but <1% in patients with normal rest ECG, exercise stress, or age of 75 to 84 years and was 2.3% to 3.7% in patients >= 85 years of age or undergoing pharmacological stress. However, compared with age-matched US population CD rates (75 to 84 years of age, 1.5%; >= 85 years, 4.8%), normal MPS CD rates were approximately one-third lower than the baseline risk of US individuals (both P < 0.05). Modeling of all-cause death in 684 patients with extended follow-up revealed that after risk adjustment, an interaction between early treatment and ischemia was present; increasing ischemia was associated with increasing survival with early revascularization, whereas in the setting of little or no ischemia, medical therapy had improved outcomes. Conclusions-Stress MPS effectively stratifies CD risk in elderly patients and may identify optimal post-MPS therapy. CD rates after normal MPS are low in all subsets in relative terms compared with the age-matched US population. (Circulation. 2009; 120: 2197-2206.)