Myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) accounts for 5-6% of all myocardial infarctions. The causes that can lead to this diagnosis are many and not always clearly identifiable; in fact, despite optimal work-up, the cause of MINOCA remains undetermined in 8-25% of patients and diagnosis represents a real challenge for the cardiologist clinician. Because patients with MINOCA have clinical outcomes comparable to those with myocardial infarction with obstructive coronary artery disease, they should undergo a careful diagnostic work-up in order to set up a therapy related to the specific diagnosis.
A 51-years old woman presented to the emergency room after a sudden onset of an oppressive, prolonged and non-radiating chest pain, with gradual resolution after intravenous nitroderivates therapy. Smoking was the only cardiovascular risk factor. A recent uncomplicated COVID 19 infection (2 months before hospital admission) was the only event reported in clinical history.
Physical examination was unremarkable with the exception of an apical mid-end systolic murmur. The electrocardiogram was normal and the Troponin T peak was 391 pg/ml. An echocardiogram showed a normal biventricular function without alterations of segmental kinetics and mitral valve prolapse with moderate degree regurgitation.
The patient was admitted to the Intensive Care Unit department and underwent a coronary angiography study with evidence of main epicardial coronaries free from stenosing atherosclerotic lesions.
In addition, a cardiac magnetic resonance (CMR) was performed before discharge, with evidence of normal biventricular systolic function in the presence of limited area of late enhancement with ischemic pattern at the level of the middle segment of the inferolateral wall of the left ventricle without edema.
In the light of the clinical instrumental picture, a diagnosis of MINOCA was made.
This clinical case is an example of how sometimes the cause relating to a MINOCA cannot always be well identified. However, the multi-imaging approach and in particular the resonance allowed to identify a localized area of late enhancement with an ischemic type pattern. The origin of the ischemia could be dated from a picture of distal embolization, from a microvascular disease or from a myocardial stretching due to prolapse.