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 infaretion 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, method: Using contrast-enhanced MRI, microvascular obstruction was defined as early hypoenhancemcm. Contrast defects were scored from 0 (no hypoenhancement) to 3 (strong hypoenh an cement). 50 patients (56 11 years) with STENII underwent PCI. Contrast-enhanced MRA (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 NIVO, whereas pre-infaretion 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 ofCK (rho=0.56; p=0.01) or Troponin 1 (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. (C)2006 Elsevier Ireland Ltd. All rights reserved.