Predictive Value of Resting Pd/Pa for Fractional Flow Reserve Assessed with Monorail Pressure Microcatheter in Real-World Practice

Background and Objectives: The aims of this study were (1) to examine the diagnostic accuracy of resting time-averaged distal coronary pressure (Pd) to mean aortic pressure (Pa) ratio to predict hyperemic fractional flow reserve (FFR) and (2) to identify a resting Pd/Pa value that can preclude the need for hyperemic FFR assessed with use of a monorail pressure catheter.

Methods: A total of 191 stenoses were assessed. After exclusions, 157 FFR data sets from 103 patients were analyzed.

Results: Resting Pd/Pa showed poor agreement with hyperemic FFR (r=0.619, P<0.001). The receiver operating characteristic curve for resting Pd/Pa with reference to hyperemic FFR of 0.80 or less showed an area under the curve of 0.800 (95% confidence interval 0.732‐0.868, P<0.001), with the greatest diagnostic accuracy of 74.5% for resting Pd/Pa of less than 0.85. Resting Pd/Pa of 0.96 or greater had a sensitivity of 100% and a negative predictive value of 100%, and resting Pd/Pa of 0.82 or less had a specificity of 98.9% and a positive predictive value of 94.1% to predict abnormal FFR of 0.80 or less. These results were consistent regardless of the vessels studied, the location of lesions, and the severity of stenosis.

Conclusions: Resting Pd/Pa showed poor agreement with hyperemic FFR assessed with use of a monorail pressure microcatheter. However, resting Pd/Pa of 0.96 or greater had excellent sensitivity and negative predictive value to predict normal hyperemic FFR, and resting Pd/Pa of 0.82 or less had excellent specificity and positive predictive value to predict abnormal hyperemic FFR.