Protection Effect Of Ischemic Postconditioning In Percutaneous Coronary Intervention On Myocardial Reperfusion Injury Of Acute Myocardial Infarction

Objective: At present, in reperfusion therapy of AMI, PCI's status is enhancing. But reperfusion therapy will bring I/R injury to myocardium to different extent, which may affect patient's prognosis directly. In order to discuss the feasibility and validity of IPC that is proposed for recent years in PCI, this research compared IPC to conventional PCI, observed IPC's influence to RA and LVRM. All patients were followed up for 12 months after PCI, adverse events like angina, cardiogenic death and heart disfunction were recorded, thus protection effect of IPC to myocardium could be infered. The purpose was to find a basis for IPC's application into PCI.Method: From March 2007 to March 2008, one hundred and twenty five patients who obtained AMI for the first time were enrolled in our hospital. Included criteria:⑴Chest pain persisted for more than 30 minutes, and not alleviated by rest or taking nitroglycerin;⑵ST-segment elevated beyond 0.1 mv at least 2 or more neighboring extremity leads or beyond 0.2 mv at precordial leads, or new left bundle branch block in electrocardiogram;⑶The peak value of typical myocardial enzyme was beyond 2 times of normal range ,and had a variation process;⑷CAG confirmed that the artery was occluded;⑸There was no collateral coronary circulation to infarction area;⑹Interval from persistent chest pain to reperfusion was in less than 12 hours . Excluded criteria:⑴Specific history of obsolete myocardial infarction, PCI or CABG;⑵TIMI reached grade 1 or collateral circulation reached grade 2;⑶Chronic heart disfunction;⑷Angina was occured in less than 48 hours before AMI;⑸IRA involved left main coronary artery;⑹Patients attended by cardiogenic shock;⑺Patients didn't agree to participate in this study. All patients received basic therapy like oxygen inhale, sedation, acesodyne and so on, then 300mg of aspirin and 300mg of Clopidogrel Sulfate Tablets. IRA and disease coronary arteries were diagnosed by CAG. Patients were divided into IPC group and conventional PCI group randomizely. IPC group adopted 30-second-perfusion/30-second-occlusion for 3 times in the following 3 minutes after reperfusion, then gained persistent perfusion. Conventional PCI group did nothing in the later 3minutes after reperfusion, then was operated routinely. Under circumstances of long or multiple disease vessels ,or slow-reflow/no-reflow, Tirofiban Hydrochloride and Sodium chloride Injection (intravenous bolus of 10ug/kg in 3 minutes, then followed by 0.15ug/kg /min), and heparin was administered for 36 hours, APTT was measured once per 6 hour, APTT value was set at (50-70seconds).The standerd of successful PCI was TIMI reached grade 3 and stenosis ratio was less than 10%, there was no PCI complication (Including main branch oppressed, serious dissection, thrombus, shock, punctured vessel complications like huge hematoma and pseudoaneurysm) and MACE in hospital. All cases took orally aspirin 300mg per day, 1 month latter decreased to 100mg per day for lifetime, took Clopidogrel Sulfate Tablets 75mg per day for 12 months. If no contraindication, all patients reveived routine medicine after PCI, such as nitrate, statins, Beta-blocker, ACEI/ARB,et al. Analyzed basic diffenent factors between the two groups.Recorded CTFC value and MBG, discovered influence of IPC. Phlebotomized, then assayed CK and CK-MB ,compared the peak. Observed RA in and after operations. Immediately after PCI, 1 week and 12 months after PCI, echocardiography was applied to observe WMSI and LVEF; Under the condition of colored doppler surveyed blood's peak rate of mitral area in early and end diastole as VE and VA, calculated VE/VA; Under TDI condition surveyed the peak rate of mitral in early and end diastole as Ea(cm/s) and Aa(cm/s) and in systole as S(cm/s), calculated Ea/Aa. Differences of left ventricle wall movement and left ventricle function were observed between IPC and conventional PCI group. Followed up for 12 months, observed cardiogenic death, target vessel revascularization again, heart disfunction. Compared heart function and prognosis between IPC group and conventional PCI group.Results: 1.There was no significant difference in interval from onset to hospital between IPC group and conventional PCI group [ (7.35±3.22) h vs. (6.94±3.86) h]; 2. There was no significant difference in interval from hospitalization to stent planting between IPC group and conventional PCI group [ (66.85±16.28) min vs. (62.76±15.92) min]; 3. Compared influence of IPC and conventional PCI to microcirculation: frame counts were: left artery descending (21.83±8.25) vs.(26.86±9.97), left circumflex (19.88±7.53) vs. (23.26±10.15), right coronary artery(20.64±6.57)vs.(25.66±10.69); Comparison of whole frame counts: 0-13 counts were 25cases (41.67%)vs.12 cases (19.36%), 13-23 counts were 29 cases (48.33%)vs.21 cases (33.87%), 23-40 counts were 6 cases (10.00%) vs.29 cases (46.77%), flow velocity of IPC group was obviously quick than that of conventional PCI group (p< 0.05), difference was significant in statistics. 4. Comparison of myocardium level reperfusion: in IPC group 51 cases (85.00%) achieved MBG grade 3, 8 cases (13.33%) achieved grade 2, 1 case (1.67%) achieved grade 0/1, in conventional PCI group there were 34 cases (54.84%) achieved grade 3, 20 cases (32.26%) achieved grade 2, 8 cases (12.90%) achieved grade 0/1,which was significant in statistics. 5. In hospital, the rate of MACE was not different, RA was 5 cases (8.33%) vs.14 cases (22.58%), difference of the latter was significant .6.The peak of myocardial enzyme in IPC group and conventional PCI group for CK was (1336±735)U/L vs. (1705±617)U/L,CK-MB was(129±76)U/L vs.(164±68)U/L, difference was significant in statistics. 7. Myocardial infarction had less influence to IPC group than to conventional PCI as echocardiography discovered,whether diastolic function or systolic function of left ventricle.12 months later after reperfusion, echocardiography inspected that S was (9.74±1.00)cm/s vs.(8.25±0.69)cm/s, Ea/Aa was (1.35±0.33) vs.(1.21±0.37) in IPC group and conventional PCI group, the difference was significant in statistics.8. After following up for 12 months, the rate of angina and target vessel revascularization was of no difference between IPC group and conventional PCI group, but NYHA in IPC group levelⅠwere 45 cases (86.54%), levelⅡ-Ⅳwere 7 cases (13.46%), in conventional PCI group levelⅠwere 33 cases (60.00%), levelⅡ-Ⅳwere 22 cases (40.00%), the difference was of statistical significance .Conclusion: 1.The success rate of IPC was equivalent to conventional PCI; IPC did not increase operation time, also was safe and effective.2.IPC could reduce reperfusion arrhythmia by comparing to conventional PCI.3.IPC could enhance coronary microcirculation and myocardial level reperfusion and was better in improving left ventricle remodeling than conventional PCI. TDI could evaluate left ventricle function more accurately.4.Life quality and prognosis of IPC was better than that of conventional PCI.