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 2:2 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. (Am Heart J 2009; 158:806-13.)