Abstract: Objective To investigate the impact of different cycle times of myocardial ischemic postconditioning on the clinical outcome and prognosis of patients undergoing primary percutaneous coronary intervention(PCI). Methods A total of 100 patients with acute ST-elevation anterior infarction were randomly assigned to 4 groups. The routine group(n=25)received conventional PCI. The first postconditioning group(IPOC-1 group, n=25)underwent 3 cycles of repetitive balloon deflation and inflation with low pressure(4-6 atm)1 minute after opening the anterior descending, and every cycle lasted for 30 seconds. The second postconditioning group(IPOC-2 group, n=25)received the same operation; however, the first cycle lasted for 30 seconds, the second 60 seconds, and the third 90 seconds. The last 山 东 大 学 学 报 (医 学 版)54卷2期 -胡浩然,等.心肌缺血后适应循环时间对急诊经皮冠状动脉介入治疗患者的影响 \=-postconditioning group(IPOC-3 group, n=25)underwent within 1 minute reflow by 3 cycles of 1-minute inflation and 1-minute deflation of the angioplasty balloon. Blood sampling for the creatine kinase isoenzyme MB(CK-MB), cardiac troponin I(cTNI)and high sensitive C-reactive protein(hs-CRP)were taken at predetermined time after PCI. Corrected Timi Frame Count(CTFC)was calculated by two senior interventional experts. All patients received Doppler ultrasound examination and rest ^99mTc- sestamibi(^99mTc-MIBI)myocardial perfusion single photon emission computed tomography(SPECT)7 days and 3 months after PCI. Results The peak(CK-MB)and cTNI concentration 72 hours after PCI of the IPOC-2 group were lower than those of the routine group, IPOC-1 group and IPOC-3 group(all P<0.05). No differences were observed in the hs-CRP concentration before PCI among the 4 groups, but the hs-CRP concentration 24 hours after PCI was lower in the IPOC-2 group compared with the other groups(all P<0.05). CTFC of the IPOC-2 group significantly reduced compared with other groups(all P<0.05). On day 7 after PCI, the LVEDD, Ea/Aa and LVEF of all 4 groups had no significant differences(all P>0.05), but the SPECT score of the IPOC-2 group was the lowest(P<0.05). After 3 months, no statistical differences were found in the LVEDD of the 4 groups; nevertheless, the LVEF, Ea/Aa and SPECT score of the IPOC-2 group tended to have the best outcome(all P<0.05). The SPECT score was significantly lowered in each group 3 months after PCI in comparison with the corresponding group 7 days after operation(all P<0.05). Conclusion The myocardial ischemic postconditioning can dramatically decrease myocardial infarction size, attenuate myocardial ischemic reperfusion injury and improve cardiac function.

Key words: Ischemic postconditioning, ST-segment elevation myocardial infarction, Time of one cycle, Primary percutaneous coronary intervention