Clinical Outcomes of Acute Myocardial Infarction Arising from Non-lipid-rich Plaque determined by NIRS-IVUS

Abstract Aims. Pathological studies have suggested that acute myocardial infarction (AMI) can be caused by plaque erosion with small or no evidence of a lipid-core. This study sought to compare the clinical outcomes after percutaneous coronary intervention (PCI) between AMI showing maximum lipid-core burden index in 4 mm (maxLCBI4mm) <400 and ≥400 in the infarct-related lesions assessed by near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS). Methods and results. We investigated 426 AMI patients who underwent NIRS-IVUS in the infarct-related lesions before PCI. Major adverse cardiovascular events (MACE) were defined as the composite of cardiac death, non-fatal MI, clinically driven target lesion revascularization (TLR), clinically driven non-TLR, and congestive heart failure requiring hospitalization. 107 (25%) patients had infarct-related lesions of maxLCBI4mm<400, and 319 (75%) patients had those of maxLCBI4mm≥400. The maxLCBI4mm<400 group had a younger median age at onset (68years [IQR: 57–78years] vs. 73years [IQR: 64–80years], P=0.007), less frequent multi-vessel disease (39% vs. 51%, P=0.029), less frequent TIMI flow grade 0 or 1 before PCI (62% vs. 75%, P=0.007), and less frequent no-reflow immediately after PCI (5% vs. 11%, P=0.039). During a median follow-up period of 31 months [IQR: 19–48 months], the frequency of MACE was significantly lower in the maxLCBI4mm<400 group compared with the maxLCBI4mm≥400 group (4.7% vs. 17.2%, P=0.001). MaxLCBI4mm<400 was an independent predictor of absence of MACE at multivariable analysis (hazard ratio: 0.30 [confidence interval: 0.11-0.82], P=0.018). Conclusion. MaxLCBI4mm<400 measured by NIRS in the infract-related lesions before PCI was associated with better long-term clinical outcomes in AMI patients.