Abstract 18799: Aborted Myocardial Infarction after Primary PCI: Insights from Magnetic Resonance Imaging in the APEX-AMI Trial
Background: Aborted myocardial infarction defined by < 2 fold elevation in biomarkers occurs in 13–14% of STEMI patients (pts). Its relationship with other metrics of infarct size and LV function defined by MRI is unclear.
Methods: Of the 5745 pts enrolled in APEX-AMI (STEMI pts undergoing primary PCI < 6hrs after symptom onset) 73 were part of a substudy including MRIs 3–5 days after randomization.
Results: Aborted MI (ST elevation/LBBB on presenting ECG with subsequent peak CK/CKMB<2 X ULN) was observed in 11% (437/3938) overall and in 19% (14/73) pts in the MRI study. Aborted MI pts tended to be older (median 62 (59–73) yrs vs. 57 (46–67); p=0.081) and have complete ST-elevation resolution 30 minutes post-PCI (≥70% resolution: 64% versus 32% p=0.076) than other MI patients. MRI revealed that aborted MI pts had smaller infarct size (4.7 vs. 14.9 LV%, p50% wall thickness) p=0.01. (See Figure)
Conclusions: In APEX-AMI, 11% of all pts had an aborted MI by biomarker evaluation, which was characterized by smaller infarcts with enhanced LV function. MRI provides corroborative evidence into the phenomenon of aborted MI as well as its pathophysiology, specifically limitation of the “wavefront” of infarct expansion resulting in more subendocardial infarcts.
- © 2010 by American Heart Association, Inc.