Prospective Comparison of FFR Derived From Coronary CT Angiography With SPECT Perfusion Imaging in Stable Coronary Artery Disease: The ReASSESS Study

OBJECTIVES: This study sought to compare the per-patient diagnostic performance of coronary computed tomography angiography (CTA)-derived fractional flow reserve (FFR CT) with that of single-photon emission computed tomography (SPECT), using a fractional flow reserve (FFR) value of ≤0.80 as the reference for diagnosing at least 1 hemodynamically significant stenosis in a head-to-head comparison of patients with intermediate coronary stenosis as determined by coronary CTA.

BACKGROUND: No previous study has prospectively compared the diagnostic performance of FFR CT and myocardial perfusion imaging by SPECT in symptomatic patients with intermediate range coronary artery disease (CAD).

METHODS: This study was conducted at a single-center as a prospective study in patients with stable angina pectoris (N = 143). FFR CT and SPECT analyses were performed by core laboratories and were blinded for the personnel responsible for downstream patient management. FFR CT ≤0.80 distally in at least 1 coronary artery with a diameter ≥2 mm classified patients as having ischemia. Ischemia by SPECT was encountered if a reversible perfusion defect (summed difference score ≥2) or transitory ischemic dilation of the left ventricle (ratio >1.19) were found.

RESULTS: The per-patient diagnostic performance for identifying ischemia (95% confidence interval [CI]), FFR CT versus SPECT, were sensitivity of 91% (95% CI: 81% to 97%) versus 41% (95% CI: 29% to 55%; p < 0.001); specificity of 55% (95% CI: 44% to 66%) versus 86% (95% CI: 77% to 93%; p < 0.001); negative predictive value of 90% (95% CI: 82% to 98%) versus 68% (95% CI: 59% to 77%; p = 0.001); positive predictive value of 58% (95% CI: 48% to 68%) versus 67% (95% CI: 51% to 82%; p = NS); and accuracy of 70% (95% CI: 62% to 77%) versus 68% (95% CI: 60% to 75%; p = NS) respectively.

CONCLUSIONS: In patients with stable chest pain and CAD as determined by coronary CTA, the overall diagnostic accuracy levels of FFR CT and SPECT were identical in assessing hemodynamically significant stenosis. However, FFR CT demonstrated a significantly higher diagnostic sensitivity than SPECT.