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 = 0.5 mV, area under the curve, AUC = 0.718, P < 0.001), or IMH(+) and IMH(−) patients (optimal threshold = 0.5 mV, 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.