Study Finds Atypical MI Causes More Frequent in Women Aged Under 65: Daily Dose

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On September 178, 2025, we reported on results from a Mayo Clinic study published in the Journal of the American College of Cardiology that examined the incidence and outcomes of myocardial infarction (MI) according to a unique pathophysiologic mechanism in a large community cohort aged ≤65 years, and to evaluate sex-differences in etiology.

The study

Researchers studied all Olmsted County, Minnesota residents aged 65 or younger who had elevated cardiac troponin T levels (≥0.01 ng/mL) between January 2003 and March 2018, indicating possible heart injury. Each case was reviewed using medical records and imaging to confirm MI and classify it into 1 of 6 causes:

1. Atherothrombosis

2. Spontaneous coronary artery dissection (SCAD)

3. Embolism

4. Vasospasm

5. MI with nonobstructed coronary arteries (MINOCA-U)

6. Supply/demand mismatch (secondary MI)

The study measured how often each type occurred and tracked long-term overall and cardiovascular-related mortality.

The findings

Investigators identified 1474 index MIs between 2003 and 2018. While more than two-thirds (68%) overall were attributed to atherothrombosis, more than half of MIs in women under 65 were caused by nontraditional factors such as SCAD, embolism, or stressors like anemia and infection. In contrast, 75% of MIs in men were plaque-related.

Women with atherothrombosis were similar in age to men (55 vs 54 years) and had comparable disease severity on angiography, but more cardiovascular risk factors. Nonatherothrombotic causes accounted for the majority of MIs in women (47% atherothrombosis vs 75% in men), including higher rates of secondary MI (34% vs. 19%) and SCAD (11% vs 0.7%).

Five-year all-cause mortality was highest in patients with secondary MI (33%), while cardiovascular mortality remained low across all groups.

Authors' comments

"This community-based study demonstrates nonatherothrombotic causes comprise an important burden of acute MI in persons age ≤65 years, particularly women. These cause-specific findings have implications for individualized management and risk stratification and provide epidemiologic benchmarking for future studies."

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