Abstract 13770: Mri-derived Changes of Cardiac Function and Scar Size Within 4 Months And Long-term Clinical Outcome in Patients With Acute Myocardial Infarction
Background: Cardiac MRI is well established as a non-invasive tool to precisely measure left ventricular systolic function (LV-EF) and infarct size using contrast-enhanced MRI. However, there are very few data relating structural and functional changes early after myocardial infarction (MI) to long-term clinical outcome. Therefore, we analyzed changes in LV-EF and in scar size during the first 4 months after MI and evaluated their long-term prognostic implications.
Methods: 397 patients underwent serial contrast-enhanced cMRI on a 1.5 Tesla scanner 10 days and 4 months after STEMI treated by PCI. LV-EF and scar size (LE-SS) were analyzed and patients were followed-up for 36 months.
Results: Four months after STEMI, LV-EF significantly improved to 3.4 ± 7.6 % (p < 0.001) and scar size was significantly (p< 0.001) reduced (-2.7±6.4 %/LV-mass). There was a significant inverse correlation between LV-EF and scar size both immediately after STEMI (r=-0.572, p <0.0001) and at four months (r=-0.690; p < 0.0001). Importantly, however, the individual functional (Delta LV-EF) and structural (Delta scar size) alterations demonstrated only a weak correlation (r=0.117, p=0.02) after STEMI. After 36 months of clinical follow-up in the group of patients with a MACE during long-term follow-up, LV-EF failed to increase at 4 months (Δ LV-EF -0.3% ± 6.68) compared to event-free patients (Δ LV-EF + 3.6%, ± 7.56; p=0.018 vs. MACE group). In contrast, changes in scar size at 4 months did not significantly differ between the MACE group (-1.6%±4.7)compared to patients without MACE ( -2.8%±6.5; p= 0.09). Caplan-Meier analysis demonstrated that recovery of LV-EF early after STEMI is significantly associated with improved outcome (p logrank Δ LV-EF = 0.017), whereas short-term alterations of scar size do not provide any significant long-term prognostic information (p logrank Δ scar size = 0.158).
Conclusion: The results of this large cohort of patients serially studied by cMRI after STEMI demonstrate that functional und structural LV changes are only weakly correlated during the first four months after STEMI. Importantly, early changes in LV-EF appear to be superior compared to changes in scar size with respect to the prediction of MACE during long-term follow-up.
- © 2013 by American Heart Association, Inc.