Impact of various types of microvascular injury on area at risk in patients with primary myocardial infarction with ST segment elevation (STEMI)

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grants Council of the Russian President for state support of young Russian scientists and state support of leading scientific schools of the Russian Federation CMR can quantify the area at risk (AAR). It includes both salvaged and infarcted myocardium. Furthermore, CMR permits to determine with high sensitivity the presence of microvascular injury phenomena: intramyocardial haemorrhage (IMH) and microvascular obstruction (MVO) in patients with STEMI. There is not enough known about the relation of AAR and different types of microvascular injury. Aim. To analyze the correlation between the risk zone and the phenomena of microvascular injury in patients with primary STEMI . Materials and methods. The study included 60 patients with primary STEMI, admitted within the first 12 hours after the onset of disease, who underwent stenting of the infarct-associated coronary artery. Exclusion criteria: pulmonary edema, cardiogenic shock, estimated glomerular filtration rate <30 mL/min/1,73 m2 or dialysis, severe comorbidity, acute psychotic disorders and inability to undergo or contra-indications for CMR. Each patient included in the study underwent CMR imaging at day 2 post-STEMI. The AAR extent was quantified on short-axis T2-STIR images. MVO and IMH were assessed using late gadolinium enhancement and T2-weighted CMR imaging. Results. It was demonstrated that the AAR occupies 12% (7,8-17,7%) of the total myocardium. Evidence of microvascular injury phenomena was present in 41 patients (68.3%), the combination of MVO and IMH - in 22 patients (36.6%). The isolated IMH phenomenon was visualized in 9 patients (15%). The isolated MVO phenomenon was visualized in 10 patients (16,7%). Relation between of size of ARR, MVO and IMH areas is demonstrated in Table 1. A comparison study showed that the ARR was larger in patients a combination of IMH and MVO. Patients with isolated IMH and isolated MVO had an ARR similar with to a group without microvascular injury. Correlation analysis showed a moderate direct correlation between the IMH and MVO sizes, and ARR (R = 0,42; p = 0,0007 and R = 0,55, p = 0,000004). Conclusions. The analysis of the influence of different microvascular injury phenotypes on the ARR of the myocardium as assessed by CMR in the early postinfarction period in patients with primary STEMI has shown that the combination of IMH with MVO associate with a large ARR. Correlations between the IMH and MVO sizes and increased ARR have been demonstrated. Table 1. CMR parametersArea at risk, %No phenomena MVO and IMH, n = 198,1 (5-17)Isolated MVO, n = 1010,1 (9-13)Isolated IMH, n = 911 (8-12)Combination of IMH and MVO, n = 2217,3 (10-27)