| Objective: This paper was to investigate protective effects of ischemic preconditioning (IP) and short-time effects of direct percutaneous coronary intervention (PCI) on myocardial viability and ventricular function in acute myocardial infarction (AMI) patients with IP.Methods: The present study was performed in eighty-seven patients (75 men, 12 women, 59.3±11.0y ) with first AMI admitted to our hospital from January,2001 to January, 2003. All patients were the first onset of AMI and accorded with the criterion of WHO. These patients received successfully the PCI without previous intravenous thrombolytic therapy. The patients who had history of old myocardial infarction and chronic heart dysfunction caused by various kinds of diseases were excluded from this study. The study patients were classified into three groups according to the presence or absence of prodromal angina: no previous angina (group A,n=30);preinfarction angina occurring within 48h before onset of AMI (group B,n=39);preinfarction angina only occurring >48h before onset of AMI (group C,n=18). All patients undervent emergency coronary angiography (CAG). The results of CAG were analyzed by two intervention caidiologists who were unaware of clinical findings. Quantitative coronary angiography (QCA) was used to analyse the condition of coronary artery,collateral circulation and spontaneous recanalization of IRA. Coronary artery stenosis ≥50% was considered significant. IRA was identified and successfully revascularized by direct PCI within 6h after onset of AMI. PCI was considered successful when thrombolusis in myocardial infarction (TIMI) grade 3 flow with residual stenosis of 20% was obtained and there were no significant complications. Left ventriculography (LVG) was performed after PCI. Left ventricular end diastolic pressure (LVEDP) was recorded and left ventricular ejection fraction (LVEF) was calculated by the area-length method. Spontaneous recanalization was defined as the presense of TIMI grade flow no less than 2 grade on the angiogram. Collateral circulation was estimated with Cortina scores and collaterals were considered significant when scores was ≥2. Myocardial enzymes were continuously measured before and after PCI. (99m)Tc-MIBI myocardial perfusion imaging (MPI) was performed at 1 week and 4 weeks. The myocardial infarction area (MIA) and the ratio of radioactivity counts in the MIA to the maximumradioactivity counts (RMIA/RMA) was detected to evaluate myocardial viability by the quantitative analysis with bull's-eye display. Equilibrium radionuclideangiocardiography (ERNA) was performed at 2 weeks. LVEF,left ventricular peak ejection rate (LPER),left ventricular time to peak ejection rate (LTPER),left ventricular peak failing rate ( LPFR) and left ventricular time to peak filling rate (LTPFR) were measured to evaluate left ventricular function; Left ventricular phase shift (LPS),Ieft ventricular full width at half maximum (LFWHM) and peak phase standard (PSD) were measured to evaluate ventricular systolic synchrony (VSS). The difference of myocardial viability and ventricular function of three groups was analysed.Results: (1) There were no significant differences among the three groups with respect to age,sex,hypertention,diabetes,hypercholesteral,addiction for smoking ,place of infarction,and time to reperfusion of IRA. (2) There were no significant difference of branches of stenosised coronary artery among the three groups;The incidence of spontaneous recanalization of IRA was higher in group B than that in group A ( 28% vs 7%, p<0.05),but there was no significant difference between group C and group A; The patients of group C had a trend of higher incidence of collaterals than those of group A( 39% vs 17%, p>0.05),but there was no apparent difference between group B andgroup A.(3) MIA was less in group B than that in grou...
|
PDF Full Text Request