Abstract: Objective To explore the effect of ischemic postconditioning on serum superoxide dismutase (SOD) and malondialdehyde (MDA) in acute myocardial infarction (AMI) and clinical significance. Methods 101 AMI patients accepted emergency percutaneous coronary intervention (PCI) were divided into postconditioning group (n=46) and control group (n=55) according to the treatment they accepted.The concentration of serum SOD and MDA were observed 4, 8, 12, 16, 20, 24, 36, and 48 h after PCI, as well as the grade of Thrombolysis
in Myocardial Infarction (TIMI) and TIMI Myocardial Perfusion Grades (TMPG), serum creatine kinase-MB (CK-MB) peak value, scoring of nuclide distribution 10 d after PCI, and frequence of cardiac events within 30 d after PCI. Results Compared with the control group, serum SOD increased (P<0.01) and MDA decreased (P<0.001) respectively 2, 4, 8, 12, 16, 20, 24, 36 and 48 h after the PCI, especially the valley of SOD and peak of MDA value in the postconditioning group; while the patient with TIMI flow of grade 3 and TMPG of grade 3 increased (P<0.05), the peak of serum CK-MB decreased (P<0.01), and the score of nuclide distribution decreased (P<0.05). After the operation for 30 days, the frequence of cardiac events was less in the postconditioning group than in the control group (P<0.05). Conclusion Ischemic postconditioning can reduce the peroxidation after PCI, to increase myocardial perfusion, reduce infarct area, and improve prognosis in acute ST-segment elevated myocardial infarction

Key words: acute myocardial infarction, ischemic postconditioning, superoxide dismutase, malondialdehyde, perfusion