The Effect of Preinfarction Angina as Ischemic Preconditioning on Myocardial Protection

ABSTRACT

BACKGROUND AND OBJECTIVES: By measuring the coronary flow reserve (CFR) and echocardiographic left ventricular function, the purpose of this study was to evaluate the effect of pre-infarction angina (PA) on myocardial protection in patients with acute myocardial infarction (AMI). SUBJECTS AND METHODS: Sixty-two patients (mean 54+/-10 years, 51 males) with first anterior AMI were studied. CFR, defined as the ratio of hyperemic (hAPV) to baseline APV (bAPV), was measured at least 24 hours after the onset of AMI at the left anterior descending artery (mean 7+/-4 days) with a Doppler wire. Echocardiography was performed at admission (baseline) and during follow-up periods (mean 9+/-7 month). All patients were divided into two groups according to the presence of PA within 72 hours prior to AMIgroup A (with PA, n=27) and group B (without PA, n=35). RESULTS: Between the two groups, CFR were higher in group A (2.1+/-0.5 vs.1.6+/-0.5, p<0.001). The baseline left ventricular ejection fraction (LVEF, %) and wall motion score index (WMSI) were better in group A than in B (53.4+/-9.7 vs. 45.1+/-8.8, p=0.001;1.42+/-0.23 vs. 1.72+/-0.28, p<0.001, respectively). LVEF (%) and WMSI during follow-up periods were better in group A than in B (61.3+/-10.2 vs. 54.4+/-13.3, p=0.03;1.24+/-0.21 vs. 1.47+/-0.37, p=0.004, respectively). CONCLUSION: Patients with PA had a significantly higher CFR and better LVF at the baseline and during follow-up periods. This study suggests that brief and repeated myocardial ischemia prior to AMI as ischemic pre-conditioning might have the effect of myocardial protection.