Impact of Early ST-Segment Changes on Cardiac Magnetic Resonance-Verified Intramyocardial Haemorrhage and Microvascular Obstruction in ST-Elevation Myocardial Infarction Patients

The aim of this study was to explore the significance of different ST-segment changes before and after percutaneous coronary intervention (PCI), in relation to cardiac magnetic resonance (CMR)-verified microvascular obstruction (MVO) along with intramyocardial hemorrhage (IMH) in ST-elevation myocardial infarction (STEMI) patients.This study enrolled 108 STEMI patients who received primary PCI and had no contraindication of CMR investigation. Sum ST-segment elevation (STE), maximal STE on admission and sum ST-segment resolution (STR), and single-lead STR and residual STE at 60 minutes after primary PCI were assessed. MVO and IMH were determined by contrast-enhanced CMR.Patients were classified into 3 groups: 30 patients with MVO(-)/IMH(-), 25 with MVO(+)/IMH(-), and 53 with MVO(+)/IMH(+). Sum STE (P=0.001), maximal STE (P<0.001), and residual STE (P=0.025) were highest and single-lead STR was lowest (P=0.044) in the MVO(+)/IMH(+) group. Receiver operator characteristics curve analysis revealed that maximal STE was the most powerful factor for distinguishing between MVO(+) and MVO(-) patients (optimal threshold=0.5mV, area under the curve, AUC=0.718, P<0.001), or IMH(+) and IMH(-) patients (optimal threshold=0.5mV, AUC=0.697, P<0.001). In multivariate analysis, maximal STE was identified as the most powerful independent predictor of MVO (odds ratio [OR]=4.30, P<0.001) and IMH (OR=2.44, P=0.001), whereas sum STE was the strongest correlate of both the number of MVO segments (r=0.42, P<0.001) and IMH segments (r=0.43, P<0.001).The presence of MVO and IMH in infarcted tissue was relevant to ST-segment changes in STEMI patients. Maximal STE was a powerful independent predictor of the presence of MVO and IMH, whereas sum STE was a strong correlate of the number of MVO and IMH segments.