Heart attacks in younger adults aren’t always due to clogged arteries. A new major study reveals striking differences between men and women, with nontraditional causes playing a big role in women’s heart health.
When it comes to heart attacks, known medically as myocardial infarctions, the general assumption is that they’re caused by a blocked artery from cholesterol build-up and clotting. However, when it comes to heart attacks in younger adults, there are other, less common causes.
A new study by the Mayo Clinic examined every person under the age of 65 in Minnesota who had evidence of heart muscle damage between 2003 and 2018 and classified them into six categories of heart attack cause. They also looked at whether causes are different in younger men and women.
“This research shines a spotlight on heart attack causes that have historically been under-recognized, particularly in women,” said Clair Raphael, MD, PhD, an interventional cardiologist in Rochester, Minnesota, and the study’s lead author. “When the root cause of a heart attack is misunderstood, it can lead to treatments that are less effective – or even harmful.”
Out of nearly 3,000 patients, about two-thirds (68%) of heart attacks were caused by the classic blocked artery and clotting, or atherothrombosis. Men were much more likely than women to have this type, whereas women were more likely to have other causes of heart attacks.
In addition to atherothrombosis, the other five heart attack causes the researchers examined were:
- SCAD (spontaneous coronary artery dissection): a tear in the artery wall
- Embolism: a clot that travels from elsewhere to the heart
- Vasospasm: temporary tightening of the artery
- MINOCA-U (myocardial infarction with non-obstructed coronary arteries not meeting another category): heart attack without a blocked artery, with no other clear cause
- Supply/demand mismatch (SSDM): heart muscle needs more oxygen than it gets, even without a blocked artery (e.g., during severe illness or stress)
SCAD was much more common in women in the community, in whom only about half of heart attacks were caused by blocked arteries (47%), compared to 75% in men. Within women’s heart attacks, the causes were SSDM (34%), SCAD (11%), embolism (2%), vasospasm (3%), or MINOCA-U (3%). Misdiagnosis was common, with over half of SCAD cases being mistaken for other types of heart attack at first.
Regarding outcomes, long-term survival was worse in people (both sexes) with heart attacks caused by SSDM; about one in three (33%) died within five years. By contrast, for heart attacks caused by SCAD, there were zero cardiovascular deaths in five years. Classic blocked-artery (atherothrombotic) heart attacks had about an 8% death rate in five years.
The study is strong because it covers an entire community over 15 years with careful adjudication. But its generalizability is limited by the single geographical setting (Minnesota), potential misclassification of heart attack cause (particularly SCAD and non-traditional causes), and changes in diagnostic practice over time. Nonetheless, the research conveys an important message.
“Our research highlights the larger need to rethink how we approach heart attacks in this patient population, and for younger adult women, in particular,” said Rajiv Gulati, MD, PhD, chair of the Division of Interventional Cardiology and Ischemic Heart Disease at the Mayo Clinic. “Clinicians must sharpen their awareness of conditions like SCAD, embolism and stress-related triggers, and patients should advocate for answers when something doesn’t feel right.”
“Understanding why a heart attack happened is just as important as treating it,” added Raphael. “It can mean the difference between recovery and recurrence.”
The study was published in the Journal of the American College of Cardiology.
Source: Mayo Clinic
