A pragmatic diagnostic approach to myocardial infarction with non-obstructive coronary arteries

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is an increasingly recognised condition and it accounts for approximately 10% of all cases of MI. Despite the absence of obstructive coronary artery disease, patients with MINOCA are at increased risk of morbidity and mortality compared to the general population. While many well recognised conditions can present as MINOCA, it can be difficult to reach a final diagnosis with certainty due to the relative infrequency of these conditions in the general population and the lack of diagnostic gold-standard tests. The most common causes of MINOCA are myocarditis, coronary vasospasm, coronary plaque disruption and coronary thrombus or embolism. These can be assessed by way of cardiac magnetic resonance imaging, intra-coronary imaging modalities and clinically relevant diagnostic blood tests, respectively. There are less common and rarer aetiologies which should be considered in the absence of an apparent cause, each with a unique diagnostic standard. By following a systematic approach of diagnostic tests, an underlying cause of MINOCA can be found in the majority of cases, allowing a directed management strategy to be pursued.