Sex Differences in Murray Law-Based Quantitative Flow Ratio Among Patients With Intermediate Coronary Lesions.

ABSTRACT

Background The Murray law-based quantitative flow ratio (µQFR) is a novel technique that simulates fractional flow reserve (FFR) from a single angiographic view. However, the impact of sex differences on the diagnostic performance of µQFR has not been investigated. Methods and Results In this study, FFR and µQFR were assessed in 497 intermediate stenoses (30%-70% by visual estimation) from 460 patients (34.3% female). Physiological significance was defined as FFR ≤0.80 or µQFR ≤0.80. After adjusting for potential confounders, female sex was independently associated with higher FFR (P=0.048 and 0.026, respectively) and µQFR (P=0.001 for both) in both fully adjusted and stepwise backward models. µQFR provided superior diagnostic accuracy compared with angiography alone for detecting FFR ≤0.80 in both women (area under the curve, 0.93 [95% CI, 0.88-0.97] versus 0.80 [95% CI, 0.73-0.86]; P=0.001) and men (area under the curve, 0.88 [95% CI, 0.84-0.92] versus 0.73 [95% CI, 0.68-0.78]; P<0.001), with comparable performance between the sexes (P=0.175). In the multivariable analysis, sex was not a significant factor contributing to the overall disagreement between FFR and µQFR. Conclusions Regardless of angiographic stenosis severity, women tend to have higher FFR and µQFR values than men. Furthermore, µQFR performs similarly well in both sexes and offers improved diagnostic accuracy over angiography alone, indicating its potential as a reliable, wire-free tool to identify functional ischemia.