Kwong RY et al. (2008) Incidence and prognostic implication of unrecognized myocardial scar characterized by cardiac magnetic resonance in diabetic patients without clinical evidence of myocardial infarction. Circulation 118: 1011–1020

Unrecognized or 'silent' myocardial infarction is common in patients with diabetes and is associated with increased morbidity and mortality. Late gadolinium enhancement (LGE) on cardiac MRI can detect myocardial scarring missed by other standard techniques. Kwong et al. conducted an observational study to determine whether this imaging technique should be used to predict major adverse cardiovascular events (MACEs) in patients with diabetes.

Cardiac MRI showed LGE in 30 of 107 patients with diabetes who had no clinical evidence of myocardial infarction by history, medical record and/or substantial Q waves on electrocardiography. The patients with LGE had significantly increased MACE rate and all-cause mortality. Indeed, the event-free survival of patients with myocardial scarring detectable by LGE was similar to that of 74 control patients with clinically apparent myocardial infarction. Furthermore, LGE, particularly in the right coronary artery territory, had a stronger association with MACEs and all-cause mortality than percutaneous coronary intervention, resting wall-motion abnormality, left ventricular end-systolic and end-diastolic volume index, and left ventricular ejection fraction.

LGE on cardiac MRI is, therefore, a useful, noninvasive marker that can identify silent myocardial infarction and predict risk of cardiovascular events in patients with diabetes. The authors of this study recommend that diabetic patients without LGE on cardiac MRI should be reassessed every 2 years, to confirm the continued absence of myocardial scarring.