Persistence of Infarct Zone T2 Hyperintensity at 6 Months After Acute ST-Segment-Elevation Myocardial Infarction: Incidence, Pathophysiology, and Prognostic Implications

Abstract

Background: The incidence and clinical significance of persistent T2 hyperintensity after acute ST-segment-elevation myocardial infarction (STEMI) is uncertain.

Methods and results: Patients who sustained an acute STEMI were enrolled in a cohort study (BHF MR-MI: NCT02072850). Two hundred eighty-three STEMI patients (mean age, 59±12 years; 75% male) had cardiac magnetic resonance with T2 mapping performed at 2 days and 6 months post-STEMI. Persisting T2 hyperintensity was defined as infarct T2 >2 SDs from remote T2 at 6 months. Infarct zone T2 was higher than remote zone T2 at 2 days (66.3±6.1 versus 49.7±2.1 ms; P<0.001) and 6 months (56.8±4.5 versus 49.7±2.3 ms; P<0.001). Remote zone T2 did not change over time (mean change, 0.0±2.7 ms; P=0.837), whereas infarct zone T2 decreased (-9.5±6.4 ms; P<0.001). At 6 months, T2 hyperintensity persisted in 189 (67%) patients, who were more likely to have Thrombus in Myocardial Infarction flow 0 or 1 in the culprit artery (P=0.020), incomplete ST-segment resolution (P=0.037), and higher troponin (P=0.024). Persistent T2 hyperintensity was associated with NT-proBNP (N-terminal pro-B-type natriuretic peptide) concentration (0.57 on a log scale [0.42-0.72]; P=0.004) and the likelihood of adverse left ventricular remodeling (>20% change in left ventricular end-diastolic volume; 21.91 [2.75-174.29]; P=0.004). Persistent T2 hyperintensity was associated with all-cause death and heart failure, but the result was not significant (P=0.051). ΔT2 was associated with all-cause death and heart failure (P=0.004) and major adverse cardiac events (P=0.013).

Conclusions: Persistent T2 hyperintensity occurs in two thirds of STEMI patients. Persistent T2 hyperintensity was associated with the initial STEMI severity, adverse remodeling, and long-term health outcome.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02072850.

Keywords: acute coronary syndrome; magnetic resonance imaging; myocardial infarction; myocardium; prognosis.

© 2017 The Authors.

Figures

Figure 1.

Two patients with a similar presentation of acute anterior ST-segment–elevation myocardial infarction. Both patients were treated by percutaneous coronary intervention and with the same antithrombotic drugs. At the end of the procedure, both patients had Thrombus in Myocardial Infarction (TIMI) coronary flow grade 3 in the culprit left anterior descending artery. A, A patient with persistent infarct zone T2 hyperintensity: cardiac magnetic resonance (CMR) imaging was performed 2 days post-revascularization. T2 mapping revealed an infarct zone T2 value of 65 ms. CMR performed at 6 mo revealed a persistently high infarct zone T2 value of 66 ms in a matched myocardial slice position to baseline. Left ventricular (LV) end-diastolic volume increased from 143 to 175 mL at 6 mo representing adverse remodeling. This patient was readmitted with heart failure after the 6-mo CMR scan. B, A patient without persistent infarct zone T2 hyperintensity: CMR was performed 2 days post-revascularization. T2 mapping revealed an infarct zone T2 value of 63 ms. CMR performed at 6 mo revealed a lower infarct zone T2 value of 53 ms. LV end-diastolic volume decreased from 120 to 118 mL at 6 mo. This patient had an uncomplicated clinical course. MRI indicates magnetic resonance imaging.

Figure 2.

Change in T2 signal in patients with ST-segment–elevation myocardial infarction with or without persisting infarct zone T2 hyperintensity at 6 mo. Infarct zone T2 decreases in the majority of patients but to a lesser degree in patients with persisting edema.

Figure 3.

Change in infarct zone T2 vs infarct zone T2 at baseline. Infarct zone T2 at baseline was negatively associated with the change in infarct zone T2 at 6 mo.