[Influences of percutaneous coronary intervention on myocardial activity in myocardial infarction patients with different viable myocardium].

OBJECTIVE:To evaluate the effect of percutaneous coronary intervention (PCI) on left ventricular function in patients with different types of myocardial infarction and to explore the correlation factors for the left ventricular function. METHODS:A total of 43 patients diagnosed as acute myocardial infarction were enrolled in this study. The perfusion and delayed enhancement magnetic resonance imaging (DE-MRI) was applied to observe the following parameters before the PCI and at month 6 after the procedure: infarct mass, left ventricular ejection fraction (LVEF) and abnormal wall motion score. The subjects were divided into the following three groups by the transmural extent of myocardial infarction manifested in the DE-MRI: the transmural enhancement group, the nontransmural group and the mixed group. Laboratory test was done to detect the level of endothelin (ET), matrix metal enzyme 9 (MMP-9) and high sensitive C reactive protein (hsCRP) before PCI and at month 6 after the procedure. The t test was used to compare the differences among the groups and the multiple regression analysis was taken to explore the correlation factors for the left ventricular function. RESULTS:Compared with the parameters before PCI, the infarct mass after PCI significantly decreased in the nontransmural group and the mixed group [(4.0 ± 2.9) g/cm(3) vs (9.8 ± 5.6) g/cm(3) and (6.0 ± 3.5) g/cm(3) vs (11.8 ± 6.2)g/cm(3), all P < 0.05], while LVEF was significantly improved after PCI in both groups [(52.6 ± 15.4)% vs (41.9 ± 16.3)%,(45.6 ± 15.4)% vs (38.9 ± 16.3)%, all P < 0.05]. The infarct mass was an independent correlation factor for LVEF before PCI (RR = 0.318, P < 0.05) and LVEF after PCI (RR = 0.293, P < 0.05) . LVEF before PCI was independently correlated with the level of hsCRP (RR = 0.318, P < 0.05). CONCLUSION:The effect of PCI on the improvement of left ventricular function differs in patients with different extent of myocardial infarction, which is correlated with the amount of survival myocardium and the inflammatory factors.