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

Abstract

BackgroundThe 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 ResultsThe 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. ConclusionsIn 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.