Real-world Validation of Fractional Flow Reserve Computed Tomography in Patients with Stable Angina: Results from the Prospective AFFECTS Trial

Background: Fractional flow reserve computed tomography (FFRct) allows for non-invasive assessment of hemodynamically significant coronary artery disease (CAD). Real-world data regarding the diagnostic performance of FFRct is scarce. We aim to validate the diagnostic performance of FFRct against invasive coronary angiography (ICA) in patients with stable angina and an abnormal single photon emission computed tomography (SPECT) study.

Methods: This prospective, single-cohort, real-world study enrolled consecutive adult patients with stable angina and an abnormal SPECT study who were referred for ICA. Prior to ICA, FFRct analysis was performed. Sensitivity and specificity of FFRct were evaluated at the patient and vessel level against ICA. Physician intuition-based diagnosis of hemodynamically significant CAD was also documented prior to ICA.

Results: A total of 66 patients were enrolled; 10 were excluded due to protocol deviation or missing studies. FFRct achieved 95% sensitivity and 83% specificity at the patient level, and 78% sensitivity and 88% specificity at the vessel level. FFRct was most accurate in the left circumflex artery (sensitivity 83%, specificity 92%) and the least in the left anterior descending artery (80% sensitivity, 78% specificity). FFRct identified hemodynamically significant CAD more accurately than physician intuition (sensitivity 95% vs 84%; specificity 83% vs 46%). If physicians had been unblinded to FFRct, ICA may have been avoided in up to 53% of patients.

Conclusion: We performed a real-world study to validate the diagnostic performance of FFRct against gold-standard invasive imaging. FFRct has high sensitivity and specificity for the diagnosis of hemodynamically significant CAD in intermediate-to-high risk patients.