Abstract 617: Early Dynamic Changes in ‘Salvaged Area at Risk’ Assessed by Serial MRI at 3t in Patients With Acute Coronary Syndrome
Introduction: Oedema imaging with cardiac magnetic resonance (CMR) can identify acutely ischemic myocardium and has been used to identify “area at risk”. While the onset of oedema is rapid, the time course of its regression is not known. We hypothesized that myocardial oedema following acute myocardial ischemia would reverse within one week post coronary intervention (PCI).
Methods & Results: 3 Tesla CMR (Siemens Trio) cine and T2-weighted (T2W) short axis images covering the entire left ventricle (LV) were obtained in acute coronary syndrome (ACS) patients at 24 – 48 hours (E1) and 5–7 days (E2) post PCI. Percentage of myocardial oedema (oedema area/total slice area: EdAr) and LV ejection fraction (EF) were assessed offline. Troponin I (Tn I) was sampled at 12 hours post admission. Two groups of male patients (6 STEMI and 6 NSTEMI) matched for age (54±8 yrs vs 59±13 yrs, p=0.45) and EdAr at E1 (24±15% and 23±14% respectively, p=0.9) were identified. Tn I levels were 4.3±2.7 μg/L in NSTEMI vs 41±16 μg/L in STEMI (p<0.004). CMR was performed 48 to 120 hours post event in NSTEMI patients. In NSTEMI patients, EdAr decreased to 15.6% (p = 0.09) between E1 and E2 (Figure⇓), while LVEF increased from 55±6 % to 61±8 % (p< 0.05). In contrast, EdAr increased in STEMI to 31±15% 5–7 days post PCI (Figure⇓). By 14 –17 days (E3) there was a significant decrease in oedema though no change in LVEF.
For equivalent initial salvaged area at risk, patients with STEMI have highertroponin and more persistent EdAr.
EdAr decreases in NSTEMI by 7 days, but increases in STEMI.
These dynamic changes identify the need to standardize timing in the assessment of area at risk.