Prognostic Impact of Hyperglycemia in Nondiabetic and Diabetic Patients With ST-Elevation–Myocardial Infarction: Insights From Contrast-Enhanced Magnetic Resonance Imaging

Previous studies have suggested that hyperglycemia on admission is a risk factor for increased mortality in patients with acute ST-elevation–myocardial infarction (STEMI). However, data regarding the relationship between hyperglycemia and myocardial damage in STEMI are scarce. This largest cardiac magnetic resonance study to date evaluating the relationship of diabetes mellitus status and elevated glucose levels on admission on myocardial damage in STEMI patients reperfused by primary percutaneous coronary intervention has 2 essential findings: (1) STEMI patients with pre-existing diabetes mellitus are at greater risk for major adverse cardiovascular events despite having similar infarct sizes and extent of reperfusion injury than patients without known diabetes mellitus. (2) Elevated glucose levels on admission are associated with greater myocardial damage (larger infarcts, more pronounced reperfusion injury, left ventricular dysfunction) and an increased risk of clinical events at long-term follow-up. However, hyperglycemia was a stronger indicator of myocardial injury in STEMI patients without previously recognized diabetes mellitus than in those with established diabetes mellitus. Thus, the authors’ study confirms and expands previous findings by demonstrating that the amount of myocardial injury does not explain the substantially higher mortality rates in diabetic patients with STEMI. Moreover, the authors could demonstrate that the relationship between hyperglycemia and myocardial damage is different in STEMI patients with and without known diabetes mellitus.