[The value of coronary angiography-derived fractional flow reserve and coronary angiography-derived index of microcirculatory resistance in coronary artery hemodynamic evaluation].

<b>Objective:</b> To evaluate the diagnostic value of coronary angiography-derived fractional flow reserve (FFR) and index of microcirculatory resistance (IMR) for identifying coronary functional abnormalities. <b>Methods:</b> This diagnostic study enrolled patients with clinically suspected or diagnosed coronary artery disease who underwent coronary angiography at Beijing Anzhen Hospital, TEDA International Cardiovascular Hospital, and Qilu Hospital of Shandong University between December 2021 and June 2022. All enrolled patients successfully underwent invasive wire-based FFR and IMR measurements during angiography. In a core laboratory, FFR and IMR for the target vessels were measured using artificial intelligence technology based on coronary angiographic images. Spearman correlation analysis was used to evaluate the correlation between angiography-derived FFR and wire-based FFR, and between angiography-derived IMR and wire-based IMR. Coronary hemodynamic abnormality was defined as FFR≤0.80; the diagnostic performance of angiography-derived FFR for identifying this abnormality was evaluated. Microcirculatory dysfunction was defined as IMR≥25; the diagnostic performance of angiography-derived IMR for identifying microcirculatory dysfunction was evaluated. <b>Results:</b> A total of 181 patients, aged (60.6±8.8) years, with 62 (34.3%) females, and 181 target vessels were included in the final analysis. Angiography-derived FFR showed a significant positive correlation with wire-based FFR (<i>r</i>=0.78, <i>P</i><0.001). For identifying coronary hemodynamic abnormality, angiography-derived FFR showed an accuracy of 89.0%, sensitivity of 88.8%, specificity of 89.1%, positive predictive value (PPV) of 88.8%, negative predictive value (NPV) of 89.1%, and an area under the receiver operating characteristic curve (<i>AUC</i>) of 0.88. Angiography-derived IMR showed a significant positive correlation with wire-based IMR (<i>r</i>=0.93, <i>P</i><0.001). For identifying microcirculatory dysfunction, angiography-derived IMR demonstrated an accuracy of 89.5%, sensitivity of 86.8%, specificity of 90.2%, PPV of 70.2%, NPV of 96.3%, and an <i>AUC</i> of 0.95. <b>Conclusion:</b> Angiography-derived FFR and IMR exhibit strong correlations with their invasive wire-based counterparts and demonstrate high diagnostic value for assessing coronary hemodynamics and coronary microcirculatory function.