Cardiac structural and functional changes in ischemia-reperfusion injury of myocardium

   The aim is to study the effect of microvascular reperfusion injury (RI) of myocardium on structural and functional changes of heart in patients with acute coronary syndrome with ST segment elevation (STE-ACS) and endovascular revascularization.   Materials and Methods. The study included 146 patients with STE-ACS (mean age 54 ± 10 years, 89 % men). Depending on the presence of microvascular RI, according to CMR, performed on 5 ± 3 days after myocardial infarction, patients were divided into groups: the first group included 73 patients (50 %) with microvasculature lesions, the second group consisted of 73 patients (50 %) without microvasculature lesions. All patients underwent endovascular myocardial revascularization within 12 hours of symptoms onset. The assessment of structural and functional parameters of heart was performed by CMR with contrast enhancement on 5 ± 3, 30 and 90 days, by echocardiography on 1-2 days, 1, 6 and 12 months after myocardial infarction.   Results. In our study microvascular RI was accompanied by a significant size of infarction, a high transmurality index (TI), a large size of edema and a low myocardial salvage index, was associated with LV dilatation, a decrease in  global and local myocardial contractility during the 12 months post-infarction period (p < 0.05). The risk of developing pathological remodeling of left ventricle with microvascular RI size >1.2 % of LV mass is OR=6.25, 95 % CI 2.25–17.35 (p < 0.001), myonecrosis size on day 5 ± 3 of MI >11.7 % of LV mass (OR=10.1, 95 % CI 4.72–21.69, p < 0.001), TI > 64.3 (OR=5.63, 95 % CI 2.37–13.39, p < 0.001), edema size >24.7 % of LV mass (OR = 2.33, 95 % CI 1.09–4.97, p < 0.02).   Conclusion. Microvascular RI of myocardium is associated with pathological remodeling of the left ventricle.