The value of microvascular obstruction according to contrast-enhanced cardiac magnetic resonance imaging in assessing the prognosis of patients with acute ST-segment elevation myocardial infarction

Aim. To study the relationship between the presence and size of microvascular obstruction (MVO) and the prognosis of patients with ST-segment elevation acute myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) within one year. Material and methods . The study included 50 patients with a first STEMI who underwent PPCI on the infarct-related artery. After 3-7 days and 12 months, contrast-enhanced cardiac magnetic resonance imaging was performed to assess left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), and MVOs. After 12 months, patients were rehospitalized and prognosis was assessed based on data on cardiovascular events. Results. Patients with MVO had a significantly lower LVEF in the acute period of MI (44,1±10,6%) compared to patients without MVO (52,9±10,5%), p=0,0209, as well as during reassessment after a year (44,8±11,1%) compared with patients without MVO (58,9±8,0%), p=0,0004. A significant inverse correlation was found between LVEF in the initial and repeat examination and MVO size in the initial examination as follows: ρ=-0,42 (95% confidence interval (CI): -0,66 — -0,12, p=0,008) and ρ=-0,61 (95% CI: -0,78 — -0,34, p=0,0001). There was also a significant inverse correlation between LVEF and MVO size at reassessment, ρ=-0,40 (95% CI: -0,65 — -0,07, p=0,0205). A significant direct correlation was identified between MVO size in the acute MI period and LVEDV one year later, ρ=0,35 (95% CI: 0,02-0,62, p=0,0409). The development of a left ventricular (LV) aneurysm was registered in 40% of patients with MVO during the initial study and was not registered among patients without MVO (p=0,0039). Conclusion. MVOs was associated with post-infarction LV aneurysm. An increase in MVO size correlated with a decrease in LVEF and an increase in LVEDV both in the acute period and one year after MI.