Impact of perfusion restoration at epicardial and tissue levels on markers of myocardial necrosis and clinical outcome of patients with acute myocardial infarction

AIMS: To assess the impact of reperfusion after primary percutaneous coronary intervention (PCI) on myocardial salvage and outcome of patients with acute ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: This study included 1,406 patients with STEMI undergoing primary PCI. Blood flow restoration at epicardial and tissue levels was assessed by Thrombolysis in Myocardial Infarction (TIMI) and myocardial perfusion grade (MPG). Patients had paired scintigraphic examinations before, and 7-14 days after intervention. Based on TIMI and MPG grades, patients were divided into three groups: patients with optimal epicardial/optimal tissue perfusion (TIMI=3/MPG=3; n=801), patients with optimal epicardial/suboptimal tissue reperfusion (TIMI=3/MPG ≤ 2; n=412) and patients with suboptimal epicardial/suboptimal tissue reperfusion (TIMI ≤ 2/MPG ≤ 2; n=193). In these groups, the median infarct size (25th-75th quartiles) in the 7-14 days scintigraphy was: 7.0% (1.0%-19.0%), 12.6% (5.0%-27.6%) and 18.7% (10.4%-33.7%) of the left ventricle (p<0.001); frequency of aborted myocardial infarction was: 15.5%, 10.0% and 4.7%, (p<0.001); estimates of 5-year mortality were: 7.8%, 16.0% and 20.1% (adjusted hazard ratio=0.43, 95% confidence interval 0.21-0.89; p=0.02 for optimal epicardial/optimal tissue vs suboptimal epicardial/suboptimal tissue reperfusion). CONCLUSIONS: In patients with STEMI undergoing primary PCI, restoration of blood flow at epicardial and tissue levels was associated with increased myocardial salvage and improved long-term survival.