Managing MINOCA: A New Scientific Statement from the American Heart Association

Among patients with acute myocardial infarction (AMI) undergoing angiography, the prevalence of myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) is estimated at 5% to 6%. The American Heart Association has now released a Scientific Statement that covers diagnosis and etiology, management, and prognosis in MINOCA.

The diagnosis relies on three criteria, with the first one dependent on the definition of AMI in the consensus statement “Fourth Universal Definition of Myocardial Infarction,” which newly distinguishes between AMI and myocardial injury (Circulation 2018; 138:e618). The other two are nonobstructive coronary arteries, with no lesions ≥50% in a major epicardial vessel, and no alternative cause for the presentation. The Scientific Statement recommends cardiac magnetic resonance imaging, if available, because it can confirm AMI and exclude other diagnoses like myocarditis, takotsubo syndrome, and cardiomyopathies. The Statement discusses both atherosclerotic causes (that is, plaque disruption, which can include plaque rupture or erosion or calcific nodules) and nonatherosclerotic causes (i.e., coronary embolism/thrombosis, coronary microvascular dysfunction, epicardial coronary vasospasm, spontaneous coronary artery dissection, and supply-demand mismatch).

The Statement names four possible components of MINOCA management:

• Emergency supportive care

• Evaluation of patients with a “working diagnosis” approach

• Cardioprotective therapies, regardless of how the MINOCA was caused

• Therapies targeted at specific causes

In most, but not all, studies of prognosis, MINOCA patients had better outcomes than their AMI counterparts with coronary artery disease but faced a high risk for recurrent events, with one study finding that 25% of patients with MINOCA experience angina in the following year. In an analysis of MINOCA patients in the SWEDEHEART registry (mean follow-up, 4 years), mortality was 13%, but under half of all deaths were cardiovascular. Also, another MI occurred in 7%, ischemic stroke in 4%, and hospitalization for heart failure in 6%.