Long-Term Prognostic Impact of Changes in Coronary Angiography-Derived Index of Microcirculatory Resistance Following PCI

초록

Background Angiography-derived index of microcirculatory resistance (angio-IMR) is a reliable measure for assessing coronary microvascular function. However, the prognostic significance of changes in angio-IMR (Delta angio-IMR) remains unclear. Objectives The aim of this study was to assess the long-term prognostic utility of Delta angio-IMR following percutaneous coronary intervention (PCI) in patients with intermediate coronary stenosis. Methods A total of 814 vessels with intermediate coronary stenosis that underwent PCI were enrolled from the FLAVOUR (Fractional Flow Reserve and Intravascular Ultrasound for Clinical Outcomes in Patients with Intermediate Stenosis) trial. The primary endpoint was target vessel failure (TVF) during long-term follow-up, defined as a composite of cardiac death, target vessel-related myocardial reinfarction, and target vessel revascularization. Results The median Delta angio-IMR was 2.02 (Q1-Q3: 0.50-5.00). Using the 75th percentile (Delta angio-IMR >5) as the cutoff, 203 vessels were assigned to the high Delta angio-IMR group. Vessels with high Delta angio-IMR demonstrated a significantly elevated risk for TVF compared with those with low Delta angio-IMR (15.62% vs 9.47%; HR: 1.82; 95% CI: 1.15-2.88; P = 0.011). High Delta angio-IMR independently predicted TVF (HR: 1.72; 95% CI: 1.04-2.83; P = 0.034). There was a notable interaction effect between Delta angio-IMR and post-PCI angio-IMR (P = 0.028). A stratified analysis by post-PCI angio-IMR revealed that vessels with high Delta angio-IMR showed a markedly increased TVF risk compared with vessels with low Delta angio-IMR in those with post-PCI angio-IMR >25 (26.2% vs 11.9%; HR: 5.18; 95% CI: 1.28-20.94; P = 0.021), whereas no such association was observed in those with post-PCI angio-IMR <= 25 (12.6% vs 9.3%; HR: 1.33; 95% CI: 0.77-2.29; P = 0.305). Conclusions An elevated Delta angio-IMR correlates with a heightened risk of TVF in vessels with intermediate coronary stenosis underwent PCI. Delta Angio-IMR could be used as a valuable risk stratification indicator, particularly in patients with high post-PCI angio-IMR. (c) 2026 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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