Background. Successful restoration of epicardial coronary artery patency by primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI) does not always lead to adequate reperfusion at the microvascular level.
Aims. This study sought to investigate the association between lipid-rich coronary plaque identified by near-infrared spectroscopy combined with intravascular ultrasound (NIRS-IVUS) and microvascular obstruction (MVO) detected by cardiac magnetic resonance imaging (MRI) after PPCI for STEMI.
Methods. We investigated 120 patients with STEMI undergoing PPCI. NIRS-IVUS was used to measure the maximum lipid-core burden index in 4 mm (maxLCBI4mm) in the infarct-related lesions before PPCI. Delayed contrast-enhanced cardiac MRI was performed to evaluate MVO 1 week after PPCI.
Results. MVO was identified in 40 (33%) patients. MaxLCBI4mm in the infarct-related lesion was significantly larger in the MVO group compared with the no-MVO group (median [interquartile range]: 745 [522–853] vs. 515 [349–698], p<0.001). Multivariable logistic regression model showed that maxLCBI4mm was an independent predictor of MVO (odds ratio: 24.7 [95% confidence interval: 2.5–248.0], p=0.006). Receiver-operating characteristic curve analysis demonstrated that maxLCBI4mm >600 was the optimal cut-off value to predict MVO (Youden index = 0.44 and area under the curve = 0.71) with a sensitivity of 75% and a specificity of 69%.
Conclusions. Lipid content measured by NIRS in the infarct-related lesions was associated with the occurrence of MVO after PPCI in STEMI.