Old Age and Myocardial Injury in ST-Segment Elevation Myocardial Infarction

Background: Little is known about the causality and pathological mechanism underlying the association between old age and myocardial injury in patients with ST-segment elevation myocardial infarction (STEMI). We evaluated the association between old age and myocardial injury in STEMI patients undergoing primary percutaneous coronary intervention (PCI) using cardiovascular magnetic resonance imaging (CMR). Methods: A total of 279 patients with STEMI who underwent primary PCI and CMR were enrolled. Of these, 52 patients were over the age of 70 years (18.6%, Age ≥70 group) and 227 patients were under the age of 70 years (81.4%, Age <70 group) at STEMI occurrence. We compared myocardial infarct size on CMR according to age at STEMI occurrence and performed inverse probability of treatment weighting. Results: On CMR analysis, myocardial infarct size on CMR tended to be greater in the Age ≥70 group than in the Age <70 group (21.2 ± 10.2% versus 19.5 ± 11.1%; p = 0.072). After performing inverse probability of treatment weighting adjustment, myocardial infarct size was significantly greater in the Age ≥70 group compared with the Age <70 group (22.6 ± 10.4% versus 19.6 ± 11.1%; p = 0.001). Subgroup analysis of patients older than 70 years revealed no significant difference in myocardial infarct size according to sex (20.1 ± 11.5% in females versus 20.4 ± 9.9% in males; p = 0.901). Conclusions: Despite appropriate coronary revascularization, old age was associated with greater extent of myocardial injury in STEMI patients.