Prognostic Value and Determinants of a Hypointense Infarct Core in T2- Weighted Cardiac Magnetic Resonance in Acute Reperfused ST-Elevation Myocardial Infarction Eitel et al: Prognostic Value of Hypointense Infarct Cores

Background A hypointense core of infarcted myocardium in T2-weighted cardiovascular MR (CMR) has been used as a noninvasive marker for intramyocardial hemorrhage. However, the clinical significance of such findings not yet been established. Aim of this study was to evaluate determinants and prognostic impact of a hypointense infarct core in T2weighted CMR images, studied in patients after acute, reperfused ST-elevation myocardial infarction (STEMI). Methods and Results We analyzed 346 STEMI patients undergoing primary angioplasty <12 hours after symptoms onset. T2-weighted and contrast-enhanced CMR was used for assessment of the area-at-risk, myocardial salvage, infarct size, hypointense core in T2weighted images and late microvascular obstruction (MO). Patients were categorized into 2 groups defined by the presence or absence of a hypointense core. Primary endpoint of the study was occurrence of major adverse cardiovascular events (MACE) defined as death, reinfarction and congestive heart failure within 6 months after infarction. A hypointense core was present in 122 (35%) patients and was associated with larger infarcts, greater amount of MO, less myocardial salvage and impaired left ventricular (LV) function (p<0.001, respectively). The presence of a hypointense core was a strong univariable predictor of MACE (hazard ratio: 2.59, confidence interval: 1.27-5.27) and was significantly associated with an increased MACE rate (16.4% versus 7.0%, p=0.006) six months after infarction. Conclusions A hypointense infarct core within the area at risk of reperfused infarcted myocardium in T2-weighted CMR is closely related to infarct size, MO and impaired LV function with subsequent adverse clinical outcome.