Hemodynamic Significance of APEXCT Coronary Angiography Combined With Dynamic CT Myocardial Perfusion Imaging in Assessing Restenosis After Coronary Stenting

This study aimed to evaluate the hemodynamic significance of in‐stent restenosis (ISR) by using a combined anatomical‐functional approach with photon‐counting CT coronary angiography (APEX‐CT CTA) and dynamic CT myocardial perfusion imaging (CT‐MPI). We prospectively enrolled 239 symptomatic patients at least 9 months after PCI. All patients underwent APEX‐CT CTA (assessing diameter stenosis [CTA%DS] and plaque composition) and CT‐MPI (measuring myocardial blood flow [MBF] and relative myocardial blood volume [rMBV]). Invasive coronary angiography (CAG) and fractional flow reserve (FFR) served as the reference standard, with a composite ISR endpoint defined as CAG%DS ≥ 90% or CAG%DS ≥ 50% with FFR ≤ 0.80. Among 239 patients, 41 (17.2%) were ISR‐positive. The ISR‐positive group had significantly higher CTA%DS, lipid plaque proportion, diabetes prevalence, and smaller/longer stents, but lower MBF and rMBV. Multivariate analysis identified CTA%DS (OR = 6.801, 95% CI: 3.014–15.346) and rMBV > 0.7 (OR = 0.231, 95% CI: 0.079–0.673) as independent predictors, and their combination yielded an AUC of 0.949. In conclusion, APEX‐CT CTA combined with CT‐MPI enables dual anatomical‐functional assessment of ISR, with CTA%DS and rMBV serving as key noninvasive indicators, though further validation of its long‐term applicability and generalizability is warranted.