OBJECTIVES: Fractional flow reserve derived from coronary CT angiography (FFRCT) is a non-invasive method for diagnosis of ischemic coronary lesions. To date, the diagnostic performance of FFRCT for lesions of intermediate stenosis severity remains unexamined.
METHODS: Among 407 vessels from 252 patients at 17 centers who underwent CT, FFRCT, invasive coronary angiography (ICA) and invasive FFR, we identified 150 vessels of intermediate stenosis by CT, defined as 30-69% stenosis. FFRCT, FFR and CT were interpreted in blinded fashion by independent core laboratories. FFRCT and FFR â‰¤0.80 were considered hemodynamically significant, while CT stenosis â‰¥50% was considered obstructive. Diagnostic performance of FFRCT versus CT was assessed for accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV). Area under the receiver-operating-characteristics curve (AUC) and net reclassification improvement (NRI) were evaluated.
RESULTS: For lesions of intermediate stenosis severity, FFRCT accuracy, sensitivity, specificity, PPV and NPV was 71%, 74%, 67%, 41% and 90%; and CT stenosis accuracy, sensitivity, specificity, PPV and NPV was 63%, 34%, 72%, 27% and 78%. FFRCT demonstrated superior discrimination compared to CT stenosis on per-patient (AUC: 0.81 vs. 0.50, P = 0.0001) and per-vessel basis (AUC: 0.79 vs. 0.53, P <0.0001). FFRCT demonstrated significant reclassification of CT stenosis for lesion-specific ischemia (NRI 0.45, 95% CI 0.25-0.65, P = 0.01).
CONCLUSIONS: FFRCT possesses high diagnostic performance for diagnosis of ischemic for lesions of intermediate stenosis severity. Notably, the high sensitivity and NPV suggests the ability of FFRCT to effectively rule out intermediate lesions that cause ischemia.