From the Guidelines
The diagnostic criteria for Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) include evidence of myocardial infarction, non-obstructive coronary arteries, and no other obvious cause for the clinical presentation, as defined by the most recent guidelines 1. The diagnosis of MINOCA is made in patients with acute myocardial infarction (AMI) that fulfills all of the following criteria:
- AMI (modified from the “Fourth Universal Definition of Myocardial Infarction” criteria): Detection of a rise or fall of cardiac troponin with at least one value above the 99th percentile upper reference limit and corroborative clinical evidence of infarction evidenced by at least one of the following:
- Symptoms of myocardial ischemia
- New ischemic electrocardiographic changes
- Development of pathological Q waves
- Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality in a pattern consistent with an ischemic cause
- Identification of a coronary thrombus by angiography or autopsy
- Non-obstructive coronary arteries on angiography, defined as the absence of obstructive disease on angiography (i.e., no coronary artery stenosis ≥50%) in any major epicardial vessel, which includes patients with normal coronary arteries, mild luminal irregularities, or moderate coronary atherosclerotic lesions (stenoses >30% but <50%) 1.
- No specific alternate diagnosis for the clinical presentation, such as non-ischemic causes like sepsis, pulmonary embolism, or myocarditis 1. MINOCA is essentially a working diagnosis that requires further investigation to determine the underlying cause, which may include coronary plaque disruption, coronary spasm, coronary microvascular dysfunction, spontaneous coronary artery dissection, thromboembolism, or supply-demand mismatch, and cardiac MRI is particularly valuable in the diagnostic workup as it can identify conditions like myocarditis or Takotsubo cardiomyopathy that may mimic MINOCA 1.
From the Research
Diagnostic Criteria for MINOCA
The diagnostic criteria for Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) involve several key elements, including:
- Acute myocardial injury detected by a highly sensitive troponin assay 2
- Absence of epicardial coronary stenosis of 50% or greater on angiography 2, 3
- Clinical presentation suggestive of myocardial ischemia 3
- Exclusion of other possible causes for cardiac troponin elevation 3
Diagnostic Approach
A multimodality approach is recommended to uncover the underlying causes of MINOCA, including:
- Cardiac magnetic resonance (CMR) to make a definite diagnosis and exclude non-ischemic causes 2, 4, 5
- Intracoronary imaging, such as optical coherence tomography (OCT), to evaluate intracoronary morphological alterations 2
- Coronary reactivity testing, including provocation testing for coronary vasospasm, in selected cases 6
Key Considerations
- MINOCA is a heterogeneous and diverse disease entity, accounting for about 6% of all acute myocardial infarction (AMI) cases 2
- The syndrome has a broad differential diagnosis, including both ischemic and non-ischemic mechanisms 6
- Establishing the underlying cause of MINOCA is possible in the vast majority of cases, and proper classification of any MI should be pursued 3