Qualitative resting coronary pressure wave form analysis to predict fractional flow reserve

Aims: The aim of this study was to evaluate the predictability of resting distal coronary pressure wave forms for fractional flow reserve (FFR). Methods and results: Resting coronary wave forms were qualitatively evaluated for the presence of (i) dicrotic notch, (ii) diastolic dipping, and (iii) ventricularisation. In a development cohort (n=88), a scoring system was developed that was then applied to a validation cohort (n=428) using a multivariable linear regression model to predict FFR and receiver operating characteristics (ROC) to predict FFR ≤0.8. In the development cohort, all three qualitative parameters were independent predictors of FFR. However, in a multivariable linear regression model in the validation cohort, qualitative wave form analysis did not further improve the ability of resting distal coronary to aortic pressure ratio (Pd/Pa) (p=0.80) or instantaneous wave-free ratio (iFR) (p=0.26) to predict FFR. Using ROC, the area under the curve of resting Pd/Pa (0.86 versus 0.86, p=0.08) and iFR (0.86 versus 0.86, p=0.26) did not improve by adding qualitative analysis. Conclusions: Qualitative coronary wave form analysis showed moderate classification agreement in predicting FFR but did not add substantially to the resting pressure gradients Pd/Pa and iFR; however, when discrepancies between quantitative and qualitative analyses are observed, artefact or pressure drift should be considered.