Gender-Based Specificities of Fractional Flow Reserve Measurement

Background: The relationship between angiographic findings and fractional flow reserve (FFR) according to gender is currently unknown. Aims: To examine gender-based differences in the concordance between angiographic and functional assessment of coronary stenosis severity. Methods: We examined 3770 coronary stenoses of stable patients undergoing both quantitative coronary angiography and FFR measurements in at least one coronary stenosis. Results: Median FFR values were higher in female as compared with male patients (0.84 vs. 0.81, p < 0.001) in the overall cohort and in the first three quartiles of diameter stenosis (DS). At receiver operator characteristics (ROC) analysis, DS was effective in predicting ischemic FFR values in both men and women. A 50% DS was the optimal cut off to identify functionally significant stenoses in the entire cohort and in male patients. In females, a higher DS threshold (≥ 59%) significantly improved lesions classification (69.4% vs. 72.4%, p = 0.034), yet at the cost of an increased false negatives rate (10.5% vs. 20.8%, p < 0.001). A lower cut-off of 50% showed a superior diagnostic accuracy for ischemic FFR values (i.e., FFR values ≤ 0.80, AUC: 0.697 vs. 0.661, p = 0.006). Female gender was independently associated with a reduced risk of ischemic FFR (OR 0.51 95% CI [0.43-0.61]). Conclusions: Female patients show higher FFR values across different DS thresholds compared to male patients. A DS ≥ 50% is the best threshold to identify ischemic FFR in both males and females. A higher threshold of DS (≥ 59%) is associated with a significant improvement in lesion classification, despite leading to increased false negatives rate.