| Serial brief episodes of ischemia with intervening reperfusion enhanced the torlerance of myocardium to subsequently sustained ischemic insult and further, the onset of infarction was delayed in pretreated hearts with short bursts of sublethal ischemia and the ultimate myocardial infarct size was significantly reduced , which resulted in recognition of the concept of ischemic preconditioning(IP).The clinical counterparts to brief periods of transient ischemia include angina, unstable angina, coronary spasm, and transient ischemia controlled by inflation of balloon during angioplasty. Patients with coronary artery disease used to experience episodes of transient ischemia without developing myocardial injury.Experimental studies had manifested that IP demonstrates chronobiologically two phase effects, that were, the classic or early preconditioning occurs and lasts 1-2 hours, another delayed or late preconditioning may occur 24 hours after a stimulus of brief repetitive episodes of ischemia and last 48-72 hours, the two forms of IP were beneficial to cardioprotection.Experimental and clinical studies had shown that chronically and repeatively myocardial ischemia can induce the coronary collateral circulation (CC) establishing well and CC plays a compensatory or alternative role in infarct related region in AMI. In clinical scenario, patients with coronary artery disease often experience episodes of brief ischemia (angina or vasospasm) which can also induce collaterals to supply blood flow to ischemic myocardium. Clinical trials had showen that well-established CC was capable of maintaining the viability of the myocardium in infarct related zone (IRZ), limiting infarct size, preserving left ventricular function, inhibiting formation of aneurysm and decreasing mortality.In clinical setting, many patients with coronary artery disease hadangina history before the onset of AMI. The outcomes of IP and CC influenced by long-term of repeative episodes of angina or the latest angina within 48 hours had been reported. Then, if did the antecedente angina and coronary collateral circulation exert the concerted protection for the ischemia-reperfused myocardium in AMI accepted direct PCI? The avalible data only suggested that the cardioprotection was produced either by CC or IP. The data may not be complete for the two aspects. Because of the two aspects being mutually a major confounding factor in the investigation of ischemia-reperfusion, there was few of reports that IP and CC take the concerted protection for the jeopardized myocardium in the setting of ischemia-reperfusion. One of the objective of the present study was to investigate the patients with AMI accepted direct PCI for exploring the correlation of IP and CC and to elucidate IP and CC take the concerted protection for the jeopardized myocardium in AMI which was independent each orther.Another was to define that the viable myocardium detected by intracoronary electrocardiogram (IC-ECG) in AMI was closely correlated with both pre-infarct angina and CC. Due to activation of the specific adenosine receptors being a key mechanism in the cardioprotection of ischemia-reperfusion, this study was carried out to explore the safety and feasibility of adenosine adjunct to primary PTC A in AMI. The methods and results of the present study are as follows:Part I The protective effects of pre-infarct angina on the myocardium experienced ischemia-reperfusion in acute myocardial infarction Objective To explore ischemic preconditioning (IP) induced by pre-infarct angina and coronary collaterals in exerting the concerted protection for the jeopardized myocardium in the setting of AMI. Methods Of 44 patients with AMI within 6 hours from the onset accepted direct PCI (percutaneous coronary intervention) were randomly divided into two groups according to with or without pre-infarct angina within 48 hours prior to AMI,which were group PAP (with pre-infarct angina) and NPAP(without pre-infarct angina),and each group was further separated into two subgroups according to w...
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