Prognostic significance and magnetic resonance imaging findings in aborted myocardial infarction after primary angioplasty

Background: Aborted myocardial infarction (MI) is defined by major (≥50%) ST-segment resolution and a lack of subsequent cardiac enzyme rise ≥2 the upper normal limit. This ultimate myocardial salvage has been observed in approximately 15% of ST-elevation MI (STEMI) patients after fibrinolysis. So far, the prognostic significance and magnetic resonance imaging (MRI) findings of an aborted MI after primary angioplasty have not been evaluated appropriately. Methods: We examined 420 consecutive STEMI patients undergoing primary angioplasty within 12 hours after symptom onset. All patients underwent MRI within 1 to 4 days. Clinical end points were major adverse cardiovascular events within 6 months after the index event. Results: Of the 420 STEMI patients, 58 (14%) fulfilled aborted MI criteria. As compared with true MI, patients with aborted MI had a significant lower infarct size, shorter pain-to-balloon time, and better left ventricular ejection fraction (P < .001, respectively). Aborted MI patients had a 6-month major adverse cardiovascular event rate of 1.7% versus 19.6% of true MI patients (P = .001). In aborted MI patients, MRI detected no myocardial scar in 30 (56%), and a minor necrosis/scar formation in 24 patients (44%). Conclusion: The proven prognostic relevance of aborted MI makes it a meaningful end point and therapeutic target in future MI studies. MRI can further distinguish between true aborted MI with absence of myocardial scar and aborted MI with scar formations.