Prediction of Fractional Flow Reserve without Hyperemic Induction Based on Resting Baseline Pd/Pa

Background and Objectives: The purposes of this study are 1) to investigate the relationship between resting baseline Pd/Pa, determined by the ratio of the pressures proximal (Pa) and distal (Pd) to the target lesion before, inducing hyperemia and fractional flow reserve (FFR) and 2) to identify a resting baseline Pd/Pa range that might reliably preclude the need for hyperemic induction. Subjects and Methods: A total of 622 pressure wire data sets obtained from intermediate stenotic lesions were analyzed. Results: There was a good linear relationship between resting baseline Pd/Pa and FFR (r=0.746, p<0.001). Receiver-operating characteristic curves of the resting baseline Pd/Pa with FFR ${\leq}0.80$ as the reference variable showed an area under the curve of 0.89 (95% confidence intervals 0.863-0.914, p<0.001) with a diagnostic accuracy of 82.3% when the resting baseline Pd/Pa was ${\leq}0.92$. These results showed that certain cutoff values can reliably predict FFR, whether positive or negative. The resting baseline Pd/Pa >0.95 (n=257, 41.3%) had a negative predictive value (NPV) of 98.1% and a sensitivity of 97.3%. the resting baseline Pd/Pa ${\leq}0.88$ (n=65, 10.5%) had a positive predictive value (PPV) of 96.2% and a specificity of 99.8%. These were consistent regardless of coronary vessel, lesion location, lesion length, or degree of stenosis. Conclusion: In intermediate lesions, the resting baseline Pd/Pa was linearly related to FFR. A certain range of the resting baseline Pd/Pa values had an excellent NPV with high sensitivity or excellent PPV with high specificity for determining the lesion significance.