Factors associated with myocardial salvage immediately after emergent percutaneous coronary intervention in patients with ST-elevation acute myocardial infarction

The amount of myocardial salvage after percutaneous coronary intervention (PCI) is reported to be a major determinant of functional recovery in patients with ST-elevation acute myocardial infarction (MI). However, factors related to the amount of myocardial salvage remain unknown. The goal of this study was to investigate the factors related to the amount of myocardial salvage after emergent PCI in patients with ST-elevation acute MI by incorporating pre- and post-treatment indices and adjunctive treatments.Technetium-99m myocardial imaging was performed before, immediately after, and one month after emergent PCI in 161 patients with ST-elevation acute MI, and the defect score was serially evaluated. A good myocardial salvage was defined as/=4 change (before minus immediately after PCI) of the defect score.Good myocardial salvage was observed in 89 patients. Based on nine clinical variables, logistic regression analysis was performed to determine the important variables related to myocardial salvage. Multivariate analysis revealed that earlier time from onset to PCI (chi (2) = 6.55, P = 0.01, odds ratio = 2.78), larger defect score before PCI (chi (2) = 7.29, P = 0.01, odds ratio = 1.13) and administration of nicorandil before PCI (chi (2) = 9.88, P = 0.008, odds ratio = 4.42) were independently associated with good myocardial salvage. Thrombolysis In Myocardial Infarction (TIMI) flow grade2 before PCI (chi (2) = 4.91, P = 0.03, odds ratio = 0.36) and TIMI flow grade/=2 after PCI (chi (2) = 4.82, P = 0.03, odds ratio = 0.31) were independently associated with poor myocardial salvage. In contrast, the number of asynergic segments before PCI, infarct-related artery, adequate collaterals before PCI and stent implantation were not determinants of myocardial salvage.This study demonstrated that patients with a greater improvement of (99m)Tc tetrofosmin myocardial uptake immediately after PCI had better recovery of left ventricular function and smaller final infarct size. Reperfusion time and TIMI flow grade/=2 after PCI were important determinants of myocardial salvage, and nicorandil was a major determinant of myocardial salvage.