Abstract 9297: Incidence and Implications of Aborted Myocardial Infarction in STREAM
Background: Timely and effective reperfusion therapy in patients (pts) with ST-segment elevation myocardial infarction (STEMI) may avoid significant necrosis. Aborted MI (AbMI) was a pre-specified (previously unreported) endpoint in the STREAM (STrategic Reperfusion therapy Early After MI) trial comparing a pharmacoinvasive strategy (Gp A) vs. primary PCI (Gp B) in STEMI pts presenting within 3 hours of symptom onset.
Methods: 1754 pts with interpretable electrocardiograms (ECGs) and sequential biomarkers were included. AbMI was defined by successful reperfusion i.e. core laboratory assessed worst lead ST-elevation resolution ≥50% (90-min post-tenecteplase (TNK) in Gp A or 30-min post-PCI in Gp B), and minimal rise in biomarkers (≤2 times ULN rise in CK or CKMB) or if unavailable, ≤5xULN rise in troponin. All pts received heparin and clopidogrel at first medical contact.
Results: In Gp A, 11.1% (n=99) had AbMI vs. 6.9% (n=59) in Gp B (p< 0.01). AbMI pts were younger, more often had prior MI, exhibited Killip I, had less baseline ΣST-deviation, and fewer Q waves within their acute infarct zone (Table). Within Gp A, AbMI pts had faster time to TNK and a lower all-cause death/shock/congestive heart failure (CHF)/re-MI than non-AbMI pts; this distinction was not evident in Gp B. Total ischemic time was 100 minutes longer in Gp B AbMI pts. Forty-five pts (i.e. 2.5%; evenly distributed by treatment) had masquerading MI with minimal biomarker elevation and persistent ST-elevation in sequential ECGs related to left ventricular hypertrophy, pericarditis, or early repolarization.
Conclusions: These data demonstrate that fibrinolysis coupled with anti-thrombotic and antiplatelet therapy more frequently aborts MI: such pts have more favorable outcomes compared to non-AbMIs. Diligent review of ECG evolution in STEMI is necessary to distinguish AbMI from infarct masquerade.
- Myocardial infarction, STEMI
- Fibrinolytic agents
- Percutaneous coronary intervention
- © 2013 by American Heart Association, Inc.