Aborted myocardial infarction in patients with ST-segment elevation myocardial infarction treated with mechanical reperfusion

Abstract

Background: Aborted myocardial infarction (abMI) is a type of acute coronary syndrome in which patients treated with reperfusion avoid the great burden of necrosis. Yet, no definition of abMI in patients undergoing primary percutaneous coronary intervention (pPCI) has been proposed so far.

Aims: This study aimed to identify patients with abMI and compare them with the remaining patients with ST‑segment elevation myocardial infarction (STEMI).

Methods: It was a retrospective study of 1693 consecutive patients with STEMI treated with pPCI. The median (IQR) follow‑up was 3.45 (1.45-5.09) years. Aborted MI was diagnosed if ST‑segment elevation was reduced by more than 50%, no new abnormal Q waves were observed, the maximal level of creatine kinase MB did not reach a value 5‑fold higher than the upper limit of normal (below 125 U/l), and there was successful reperfusion defined as the Thrombolysis in Myocardial Infarction score of 3 after PCI.

Results: Using our definition, abMI was diagnosed in 176 cases (10.4%). Compared with the remaining patients with STEMI, those with abMI were younger (mean [SD] age, 61.8 [11.5] vs 64.4 [11.6] years; P = 0.005) and were more frequent smokers (48.9% vs 36.7%; P = 0.002). They had greater left ventricular ejection fraction (median [interquartile range (IQR)], 49% [40%-55%] vs 55% [51%-60.5%]; P <0.001), were discharged earlier from the hospital (hospitalization time, median [IQR], 73 [60-90.5] hours vs 87 [69-98] hours; P <0.001), and had a lower mortality rate at 1 month and long‑term follow‑up (2.27% vs 8%; P = 0.006 and 10.8% vs 23.9%; P <0.001, respectively).

Conclusion: Patients with abMI had better short‑ and long‑term outcomes than other patients with STEMI. Some negative cardiovascular factors such as smoking were more often observed in the abMI group.