Are familial risks of myocardial infarction with non-obstructive coronary arteries shared with obstructive coronary artery disease?

This editorial refers to ‘Familial risk of myocardial infarction with non-obstructive and obstructive coronary arteries: a nation-wide cohort study’, by F.H.K. Hakansson et al., https://doi.org/10.1093/eurjpc/zwae313. Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA) is an increasingly recognized clinical entity that is found in ∼6–10% of patients presenting with a clinical MI.1,2 The definition of MINOCA is contingent upon meeting the Fourth Universal Definition of MI, as well as the absence of epicardial coronary artery stenosis ≥ 50% on coronary angiography and no other overt cause for the clinical presentation. In the contemporary era, the diagnosis of MINOCA should be used exclusively to indicate an ischaemic cause for the presentation.2 Practically, many patients are initially given a working diagnosis of MINOCA based on clinical presentation and angiographic findings. They may later be found to have alternative diagnoses that mimic MINOCA, such as myocarditis and Takotsubo syndrome that do not qualify as true MINOCA. We have learned from the seminal Heart Attack Research Program (HARP) study that the majority of patients with MINOCA have an underlying atherosclerotic cause that was not readily detected on coronary angiography.3 When optimal coherence tomography was performed in combination with cardiac magnetic resonance imaging (CMR), potential mechanism of MI was identified in 84.5% of women. The majority of these patients had an ischaemic cause of MI (75.5%), with the most common aetiology being missed plaque rupture, intraplaque cavity, or layered plaque. Subsequent cardiac MRI studies have confirmed this.