Microcirculatory resistance after primary percutaneous coronary intervention predicts residual myocardial damage: a post hoc analysis from the CLEVER-ACS trial

Abstract Introduction Coronary microvascular dysfunction has been associated with adverse cardiovascular events following acute myocardial infarction. This study evaluates the role of the angiography-derived index of microcirculatory resistance (angio-IMR) in predicting myocardial damage in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Material and Methods In this post hoc analysis of the Controlled Level Everolimus in Acute Coronary Syndromes (CLEVER-ACS) trial, the associations between post-PCI angio-IMR of infarct-related coronary arteries (IRAs) and infarct size, microvascular obstruction (MVO), and left ventricle ejection fraction (LVEF) at 30 days as assessed with cardiac magnetic resonance (CMR) imaging were investigated. High post-PCI angio-IMR value was defined as a value >40 U. In non-IRAs angio-IMR was measured before the IRA-PCI. Results A total of 52 IRAs and 94 non-IRAs of 52 patients were included in the analysis. Post-PCI Angio-IMR was 41.5 (IQR 28.5–55.7) U in IRAs and pre-PCI Angio-IMR was 43.7 (31.7–54.0) U in non-IRAs (p = 0.70). Patients with high post-PCI angio-IMR (52%) exhibited a larger myocardial infarct size (36.0 [23.0–52.5] g vs. 14.5 [6.50–26.5] g, p < 0.001) and a lower LVEF (46.5 [39.5–49.5] % vs. 55.0 [48.0–61.4] %, p = 0.002) at 30 days as compared to those with low post-PCI angio-IMR values. Post-PCI angio-IMR correlated with myocardial infarct size (r = 0.45, p = 0.001) and extent of MVO (r = 0.40, p = 0.004) at 30 days. Post-PCI angio-IMR predicted myocardial infarct size (AUC = 0.78 [0.65–0.92], p = 0.001) and extent of MVO (AUC = 0.74 [0.60–0.89], p = 0.009) at 30 days. Conclusion In patients with STEMI undergoing PCI, post-PCI angio-IMR was identified as independent predictor of myocardial infarct size and extent of MVO at 30 days. The assessment of post-PCI angio-IMR values may represent a novel tool for early risk stratification of patients with STEMI.Central illustration