Nonatherothrombotic Causes Account for Much of MI Burden in Younger Adults

TUESDAY, Sept. 23, 2025 (HealthDay News) — For persons aged 65 years and younger, nonatherothrombotic causes comprise a considerable burden of acute myocardial infarction (MI), according to a study published in the Sept. 23 issue of the Journal of the American College of Cardiology.

Claire E. Raphael, M.B.B.S., Ph.D., from the Mayo Clinic in Rochester, Minnesota, and colleagues examined the incidence and outcomes of MI in a community cohort aged 65 years and younger. MI was assigned to one of six adjudicated pathophysiologic mechanisms: atherothrombosis, spontaneous coronary artery dissection (SCAD), embolism, vasospasm, myocardial infarction with nonobstructed coronary arteries not meeting another category (MINOCA-U), and supply/demand mismatch secondary MI.

During 15 years, 4,116 myocardial injury events occurred in 2,780 patients. The researchers found that 1,474 events were classified as index MI, 68 percent of which were caused by atherothrombosis. Women had a much lower population incidence of MI, especially MI caused by atherothrombosis (48 versus 137 per 100,000 person-years and 23 versus 105 per 100,000 person-years). Women had a higher incidence of SCAD (3.2 versus 0.9 per 100,000 person-years); at index presentation, 55 percent of cases were misclassified as MINOCA or atherothrombosis. The majority of cases in women compared with men were due to nonatherothrombotic causes (atherothrombosis, 47 versus 75 percent; secondary MI, 34 versus 19 percent; SCAD, 11 versus 0.7 percent; embolism, 2 versus 2 percent; vasospasm, 3 versus 1 percent; MINOCA-U, 3 versus 2 percent).

“This research shines a spotlight on heart attack causes that have historically been under-recognized, particularly in women,” Raphael said in a statement. “When the root cause of a heart attack is misunderstood, it can lead to treatments that are less effective — or even harmful.”

One author disclosed ties to industry.

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