Abstract 13372: Diagnostic Value of a Novel Coronary Computed Tomography Angiography-based Approach for Assessing Fractional Flow Reserve: Comparison with Invasive Measurement

Background: Noninvasive fractional flow reserve (FFR) from cCTA correlates well with invasive FFR and substantially improves the detection of obstructive CAD. However with current algorithms, CT-based FFR is derived off-site in an involved, time-consuming manner. We sought to investigate the diagnostic performance of a novel CT-based FFR algorithm (Siemens, Germany), developed for time-efficient in-hospital evaluation of hemodynamically indeterminate coronary lesions. Methods and Results: In a blinded fashion, CT-based FFR was assessed in 67 coronary lesions of 53 patients. Pressure guidewire-based FFR<0.80 served as the reference standard to define hemodynamically significant stenosis and assess the diagnostic performance of CT-based FFR compared to standard evaluation of cCTA (stenosis ≥50%). On a per-lesion and per-patient basis, CT-based FFR resulted in a sensitivity of 85% and 94%, specificity of 85% and 84%, positive predictive value of 71% and 71%, and negative predictive value of 93% and 97%. The area under the ROC curve on a per-lesion basis was significantly greater for CT-based FFR compared with standard evaluation of cCTA (0.92 vs. 0.72, p=0.0049). A similar trend, albeit not statistically significant, was observed on per-patient analysis (0.91 vs. 0.78, p=0.078). Mean total time for CT-based FFR was 37.5±13.8 min. Conclusions: The CT-based FFR algorithm evaluated here outperforms standard evaluation of cCTA for the detection of hemodynamically significant stenoses while allowing on-site application within clinically viable timeframes.