A normal stress SPECT scan is an effective gatekeeper for coronary angiography

Background: The effectiveness of stress single photon emission computed tomography (SPECT) as a gatekeeper for coronary angiography has not been extensively investigated. The characteristics of patients referred for early angiography after a normal stress SPECT study have not been described. Methods and Results: Over a 10-year period, 14,273 patients without documented coronary artery disease (CAD) underwent stress SPECT. Images were abnormal in 47% and normal in 53%. The overall survival rate at 15 years was 55% for patients with abnormal images versus 71% for those with normal images (P < .001). Early coronary angiography (≤3 months) was performed in only 97 patients (1.3%) with normal SPECT studies versus 1,756 patients (26%) with abnormal SPECT studies (P < .001). Most patients with normal SPECT studies referred for early angiography (85%) had clinical, exercise, or scintigraphic findings worrisome for CAD. Two thirds of these highly selected patients with normal SPECT studies who underwent angiography did not have significant CAD; the remaining one third had primarily 1- and 2-vessel CAD. Conclusions: Stress SPECT is an effective gatekeeper for coronary angiography. The annual overall mortality rate for patients with normal images was 1.9%. Only 1.3% of patients with normal images were referred for early angiography.