Background: The integrated ST segment elevation score (ISSTE) score objectively quantifies the ECG changes before and after primary percutaneous coronary intervention (pPCI) for ST segment elevation myocardial infarction (STEMI). The inflammatory response is a major component in scar formation and remodeling process of the myocardial tissue following myocardial infarction (MI). Cardiac magnetic resonance imaging (CMR) precisely quantifies the cardiac function and assesses the pattern of the myocardial scar tissue. The aim of the study was to evaluate the relations between the ISSTE score and: (1) acute inflammatory biomarkers and (2) extent of the myocardial scar determined by CMR in STEMI treated with pPCI. Material and methods: One hundred thirty STEMI patients were included in the study, who underwent pPCI in the first 12 hours from symptom debut. ISSTE-1 was calculated at presentation and 2 hours following pPCI (ISSTE-2). Inflammatory biomarkers were determined at admission and day 5, followed by LGE-CMR at 4 weeks, with quantification of cardiac function and extent of infarct size (IS) and transmurality. Patients were divided in low and high ISSTE groups based on the median values. Results: No significant differences were noted in terms of CMR parameters or inflammatory biomarkers and between the groups with low or high ISSTE-1. Significantly higher levels of day-5 hs-CRP (p = 0.03) and day-1 IL-6 (p = 0.02), MMP-9 (p = 0.05) were recorded in high ISSTE-2 groups. LV IS mass (23.11 ± 5.31 vs. 57.94 ± 8.33, p = 0.001), percentage (13.55 ± 6.22 vs. 27.15 ± 7.12, p = 0.001) and transmurality (p = 0.001) was significantly higher in ISSTE-2 group. ISSTE-2 significantly correlated with LV IS mass (r = 0.391, p <0.0001), percentage (r = 0.541, p <0.0001) high transmurality (r = 0.449, p <0.0001) and LV EF (r = -0.397, p <0.0001). Conclusions: A high ISSTE-2 score is associated with increased inflammatory response exhibited by elevated serum IL-6 and MMP-9 levels determined on the day of admission, and with persistently increased serum hs-CRP levels on day 5 of the acute event. A higher ISSTE-2 score is associated with larger myocardial scar extent expressed by IS, higher transmurality and reduced LV EF at 1-month LGE CMR follow-up.
