Dynamic Changes of Edema and Late Gadolinium Enhancement After Acute Myocardial Infarction and Their Relationship to Functional Recovery and Salvage Index

Abstract

Background Changes in the myocardium in acute ischemia are dynamic and complex and the characteristics of myocardial tissue on cardiovascular magnetic resonance (CMR) in the acute setting are not fully defined. We investigated changes in edema and late gadolinium enhancement (LGE) with serial imaging early after acute MI, relating these to global and segmental myocardial function at 6 months. Methods and Results CMR scans were performed on 30 patients with ST elevation MI (STEMI) treated by primary PCI at each of 4 time points: 12-48 hours (24H); 5-7 days (1W); 14-17 days (2W); and 6 months (6M). All patients showed edema at 24H. The mean volume of edema (% LV) was 37 ± 16 at 24H and 39 ± 17 at 1W with a reduction to 24 ± 13 (P < 0.01) by 2W. Myocardial segments with edema also had increased signal on LGE at 24H (kappa = 0.77; P < 0.001). The volume of LGE decreased significantly between 24H and 6M (27 ± 15 % vs. 22 ± 12 %; P = 0.002). Of segments showing LGE at 24H, 50% showed resolution by six months. In segments with such a reduction in LGE, 65% also showed improved wall motion (P < 0.0001). The area of LGE measured at 6M correlated more strongly with troponin at 48h (r = 0.9; P < 0.01) than LGE at 24H (r = 0.7). The difference in LGE between 24H and 6M had profound effects on the calculation of salvage index (26 ± 21 % at 24H vs. 42 ± 23 % at 6M; P = 0.02). Conclusions Myocardial edema is maximal and constant over the first week post MI, providing a stable window for the retrospective evaluation of area at risk. By contrast, myocardial areas with high signal intensity in LGE images recede over time with corresponding recovery of function, indicating that acutely detected LGE does not necessarily equate with irreversible injury and may severely underestimate salvaged myocardium.

Alterations in Cardiac Deformation, Timing of Contraction and Relaxation, and Early Myocardial Fibrosis Accompany the Apparent Recovery of Acute Stress-Induced (Takotsubo) Cardiomyopathy: An End to the Concept of Transience

“…The increased LV mass 24 is presumably a reflection of the significant myocardial edema seen in the myocardium during the acute stage, previously reported by us and others 7,21,25 . There is extensive evidence that pre-contrast T1 mapping is reflective of edema, previously provided from our group 26 and by others [27][28][29] . Here we replicate our previous findings 7 showing that LV edema subsides in the previously well contracting segments.…”

Temporal Evolution of Myocardial Hemorrhage and Edema in Patients After Acute ST‐Segment Elevation Myocardial Infarction: Pathophysiological Insights and Clinical Implications

“…For myocardial edema to be taken as a retrospective marker of the area at risk,12, 13 its initial size should be stable. Dall'Armelina et al14 reported that the extent of edema was maximal within the first 5 to 7 days after MI but then decreased in size subsequently. Recently, Fernández‐Jiménez et al15, 16 assessed myocardial edema in a swine model of MI (with or without reperfusion) at 2 hours, 24 hours, 4 days, or 7 days (n=5 per group) using CMR and quantification of myocardial water content by postmortem tissue desiccation.…”

Stress Cardiac MRI in Women With Myocardial Infarction and Nonobstructive Coronary Artery Disease

“…We do not know whether perfusion abnormalities may have evolved between presentation and CMR imaging, but T2+ and LGE are known to persist over this time period. 41 Fully quantitative myocardial perfusion analysis is superior to qualitative and semiquantitative methods but was not performed in this study. 42 Invasive coronary flow reserve is the microvascular disease reference standard, but it was not measured in this study to avoid excessive use of invasive testing given that IVUS was performed.…”