Correlation of serial cardiac magnetic resonance imaging parameters with early resolution of ST-segment elevation after primary percutaneous coronary intervention

Background: The aim of the present study was to determine whether the parameters of cardiac magnetic resonance imaging (CMRI) might correlate with early ST-segment resolution (STR) after primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI). Methods and Results: CMRI was performed in 45 STEMI patients (age: 56.6±13.0 years) at 8.2±8.0 days (early phase) and 3.3±1.1 months (late phase) after successful PCI. CMRI parameters were compared between 2 groups: ≥70% STR (group 1, n=21) and <70% STR (group 2, n=24). Both groups had similar baseline characteristics, except for a higher frequency of ≥2 myocardial blush grade and shorter pain-to-balloon time in group 1. Early-phase CMRI showed that persistent microvascular obstruction (PMO) (38.1% vs 91.7%, p<0.001) occurred less frequently and the percent infarct mass against total left ventricular (LV) mass (17.7±8.7% vs 29.1± 13.4%, p=0.001) was smaller in group 1. Late-phase CMRI revealed a significant increase in LV end-diastolic volume (-1.5±8.7 vs 14.5±25.5 ml, p=0.026) and reduced ejection fraction (55.0±9.9% vs 47.8±11.1%, p=0.027) in group 2. Conclusions: CMRI demonstrated that early STR might be related to PMO and infarct size, and predicts LV dysfunction and adverse LV remodeling. Also, early-phase CMRI findings are comparable to late-phase CMRI in association with early STR.