Stress single photon emission computed tomography for detection of coronary artery disease and risk stratification of asymptomatic patients at moderate risk.

BACKGROUND: The American College of Cardiology Foundation/American Society of Nuclear Cardiology appropriateness criteria document assigns single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) a rating of uncertain for detection and risk assessment of coronary artery disease (CAD) in asymptomatic patients at moderate risk. METHODS AND
RESULTS: The nuclear cardiology database was used to identify 260 asymptomatic patients (67 +/- 8 years, 72% men) without known CAD who were at moderate CAD risk according to the Framingham risk score. SPECT MPI images were categorized using the summed stress score (SSS). Mean follow-up 9.9 +/- 3.0 years. Abnormal SPECT MPI scans were present in 142 patients (55%). By SSS categories, SPECT scans were low-risk in 67%, intermediate-risk in 20%, and high-risk in 13% of patients. Overall survival at 10 years was 79%, significantly better than the age- and gender-matched Minnesota general population (P < 0.001). Survival was 60% for patients with high-risk scans (95% CI 45-80%), 79% with intermediate-risk scans (95% CI 69-91%), and 83% with low-risk scans (95% CI 77-88%) (P = 0.03), including 84% (95% CI 77-91%) with normal scans.
CONCLUSIONS: In this retrospectively identified group of asymptomatic patients at moderate CAD risk, stress SPECT MPI was effective for the detection and risk stratification of CAD. Average annual mortality was 4.0% in patients with high-risk scans vs 1.6% in patients with normal scans.