Role of pre-infarction angina and inflammatory status in the extent of microvascular obstruction detected by MRI in myocardial infarction patients treated by PCI

Background, objectives The extent of microvascular obstruction (MVO) during myocardial infarction referred to as the “no-reflow phenomenon”, may determine myocardial damage. Our study aimed to investigate the incidence and the influencing factors of MVO in patients with ST-elevation myocardial infarction (STEMI) treated by primary percutaneous intervention (PCI). Patients, methods Using contrast-enhanced MRI, microvascular obstruction was defined as early hypoenhancement. Contrast defects were scored from 0 (no hypoenhancement) to 3 (strong hypoenhancement). 50 patients (56 ± 11 years) with STEMI underwent PCI. Contrast-enhanced MRI (6 ± 2 days after STEMI) and biochemical parameters were evaluated. Results Microvascular obstruction (score 1 to 3) was observed in 90% of the patients and major microvascular obstruction (score 2–3) in 54%. In univariate analysis, leukocytes and CRP levels were associated with MVO, whereas pre-infarction angina and prior medication by aspirin or calcium channel antagonist appeared protective. Microvascular obstruction intensity positively correlated with baseline inflammation status assessed by C-reactive protein and leukocytes (rho = 0.43 and rho = 0.44; p = 0.003), the peak of CK (rho = 0.56; p = 0.01) or Troponin I (rho = 0.59; p = 0.01) and negatively correlated with LVEF (rho = − 0.44; p = 0.002). Multivariate analysis identified the absence of pre-infarction angina as the only independent predictor for microvascular obstruction (odds ratio, 8.35, 95% confidence interval 1.27–54.71; p = 0.027). Conclusion MRI-detected microvascular obstruction has a high incidence in patients with STEMI treated by primary PCI and determines post-MI LVEF even in patients with post PCI TIMI 3 flow score. Pre-infarction angina appears to be an independent determinant of the extent of MVO detected by MRI.