Acute myocardial infarction related to coronary artery embolism: A systematic cardiac and cerebral magnetic resonance imaging study

Abstract

Background: Coronary artery embolism (CAE) is a rare, non-atherosclerotic cause of acute myocardial infarction (MI). Atrial fibrillation (AF) is the most frequent cause of CAE, and can be associated with multiple embolisms, particularly in the brain.

Aims: To characterize CAE-related myocardial injury, assess the proportion of cardiocerebral infarction and characterize brain injuries associated with dual embolism.

Methods: In this prospective study, patients with CAE-associated MI underwent (1) cardiac magnetic resonance imaging (MRI) to assess the extent of infarct transmurality and myocardial necrosis size and (2) brain MRI to assess the proportion of simultaneous cardiocerebral infarction. We screened 1401 consecutive patients with de novo acute MI from January 2019 to June 2021. CAE was diagnosed based on clinical, angiographic and diagnostic imaging criteria.

Results: Overall, 29/1401 patients presented with CAE (2.1%), of whom 21 underwent cardiac and cerebral MRI. Of these, nine (43%) had an ischaemic stroke, and AF was the leading cause of CAE in 14 patients (67%). Multiple CAE were common at coronary angiography (33%). Four patients (19%) had left atrial appendage thrombus - 4/9 patients (44%) with a stroke but 0/12 patients without a stroke. On cardiac MRI, the median (interquartile range) number of segments with acute infarction was 3 (0-11) in patients with stroke and 3 (1-6) in those without. Most acute ischaemic strokes (78%) were localized in the superficial sylvian territory and only 2/21 patients (10%) had stroke sequelae.

Conclusion: MI-related to CAE was associated with infarctions of average size but multiple locations. Systematic brain MRI revealed that 33% of cases were associated with a stroke, which was generally asymptomatic. Further studies are required to better characterize the pathophysiology, clinical course and prognostic value of CAE. Moreover, optimal management strategies remain to be determined.

Keywords: Accident vasculaire cérébral; Atrial fibrillation; Coronary artery embolism; Embole coronaire; Fibrillation atriale; Imagerie par résonance magnétique; Infarctus du myocarde; Magnetic resonance imaging; Myocardial infarction; Stroke.