Background: Microvasculature damage after myocardial infarction (MI), known as "no-reflow" phenomenon, may occur in some patients with acute MI in spite of invasive treatment and opened infarct-related coronary artery. There are several non-invasive and invasive methods used for the coronary flow assessment at the tissue level.
Aim: To compare the value of intravenous contrast echocardiography (MCE) in detecting myocardial perfusion defects in patients with acute MI with (99m)Tc MIBI SPECT study.
Methods: Sixteen patients (11 males, 5 females, mean age 55.4+/-10.2 years) underwent primary coronary angioplasty or facilitated angioplasty (with reduced dose of a fibrinolytic drug and glycoprotein IIb/IIIa inhibitor) (PCI) for acute anterior MI. TIMI grade flow, TIMI Myocardial Perfusion Grade (TMPG), corrected TIMI frame count (cTFC), wall motion score index (WMSI) and segmental perfusion by myocardial contrast echocardiography (MCE) were estimated in real time before and immediately after PCI. MCE was repeated on the third day after PCI. All patients underwent (99m)Tc MIBI SPECT study (SPECT) while at rest on the third day after PCI. The area at risk was defined as the number of segments with no perfusion before angioplasty. Reflow was defined as an increase in contrast score in the same segments after angioplasty.
Results: Baseline MCE showed 95 segments with perfusion defects. Immediately after PCI, 77 segments were found with perfusion defect; in 10 patients improvement of myocardial perfusion was observed whereas in 6 patients perfusion defect remained unchanged. On the third day further improvement was observed in 8 patients. The number of segments with perfusion defect decreased to 53. SPECT detected perfusion defect in 54 segments. The agreement between MCE and SPECT for detecting perfusion abnormality was 98% (kappa 0.94).
Conclusions: MCE is a safe technique for detecting myocardial perfusion in patients with acute MI. MCE proves that both primary and facilitated angioplasty improve myocardial perfusion in two thirds of patients with acute MI. Serial MCE allows identification of patients with both early and late improvement of myocardial perfusion. There is a very strong correlation between MCE and SPECT in the assessment of perfusion defects.