More than half of heart attacks in younger women stem from causes other than clogged arteries Digest
It is often assumed that most heart attacks are caused by blocked arteries, but a new study suggests that this is not necessarily true, especially for younger women. Researchers from the Mayo Clinic examined heart attacks in patients younger than 66 to uncover exactly what was happening, and compared men and women to see how causes and outcomes differed.
The team analyzed medical records from all residents of Olmsted County, Minnesota, who had elevated levels of troponin T (a blood marker of heart injury) between 2003 and 2018. After excluding heart attacks related to medical procedures, they reviewed 1,474 cases in detail. Each was classified into one of six biological mechanisms: atherosclerotic disease, spontaneous coronary artery dissection (SCAD, a tear in a heart artery wall), coronary embolism (a blood clot from elsewhere in the body that blocks a heart artery), coronary artery spasm (a sudden tightening of a heart artery that briefly cuts off blood flow), a myocardial infarction with non-obstructed arteries that could not be otherwise explained (often called MINOCA), or an oxygen supply–demand mismatch caused by systemic illnesses such as hypotension, arrhythmia or anemia.
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The results revealed striking sex differences in how heart attacks occur:
- Among the 1,474 heart attacks, about two-thirds were caused by atherosclerotic disease. The rest involved oxygen-supply problems or other non-atherosclerotic mechanisms.
- In women, non-atherosclerotic events made up the majority of heart attacks: 47% were due to atherosclerotic disease, 34% to oxygen supply-demand imbalance, 11% to spontaneous artery tears, and smaller fractions to spasm, embolism, and unclassified cases.
- SCAD was about five times more common in women than men. More than half of these cases were initially misdiagnosed as heart attacks caused by blocked arteries.
- The risk of dying within five years varied by cause. Those with oxygen supply-demand imbalance had the highest overall mortality, at about one-third. By contrast, people with SCAD had no cardiovascular deaths during follow-up.
These findings highlight that in younger adults, particularly women, heart attacks are often not caused by blocked arteries. Instead, they can arise from tears, spasms, or systemic stresses that reduce blood flow to the heart. Detecting the causes correctly is essential because treatments differ; for example, unnecessary stents may cause additional injury rather than benefit, while overlooking embolic, spasm-related, or MINOCA cases can allow recurrence. Some of the triggers, such as anemia, may also be easier to identify and treat early, offering opportunities for prevention.
The authors caution that the study included only patients who had troponin measured, so it may have missed those who died before reaching the hospital. Moreover, most participants were white, and not all underwent advanced imaging. Even so, this population-wide analysis provides the clearest picture yet that younger women face a distinct pattern of heart attack causes, one that standard diagnostic assumptions often miss. Learn more about myocardial infarction (heart attack) in our detailed topic article.