Additional heart imaging can benefit women with unexplained heart attacks

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In a new study, researchers found that diagnostic imaging techniques were able to find the underlying cause of heart attack in many women who had no major artery blockage.

The research was conducted by a team at New York University.

Previous research has found that up to one in 10 heart attacks among adults is classified as MINOCA, or a heart attack with non-obstructive coronary arteries, as determined by an angiogram (heart x-ray).

Women are three times more likely to have MINOCA than men, and these non-obstructive heart attacks are also twice as common in non-white patients than white patients.

In the study, the team assessed the mechanisms of MINOCA and tried to find the cause of the heart attack in these patients.

They enrolled 301 women who experienced a heart attack but who did not have prior obstructive coronary artery disease and had no visible blockages on an angiogram.

Women diagnosed with MINOCA received two additional imaging tests:

coronary optical coherence tomography (OCT), which is performed as part of an angiogram and uses light waves to take near-photographic quality images of blood vessel walls; and

cardiac magnetic resonance imaging (MRI), which shows the areas of the heart muscle that have been injured and whether that injury is related to decreased blood flow, inflammation or another reason.

The results of images from OCTs and cardiac MRIs explained why women had symptoms and blood tests consistent with a heart attack for 84% of the study participants:

Three-quarters of the women with abnormal optical coherence tomography or cardiac MRI had evidence of heart damage from reduced blood flow.

The arteries often had ruptured plaque or recently ruptured plaque as a cause of the heart attack.

This is akin to a typical heart attack with blocked arteries but with an important difference: the plaques that ruptured were smaller than in a typical heart attack.

Cardiac MRIs showed evidence of heart damage related to reduced blood flow in more than half of the women overall, and in two-thirds of those with a causal finding on the optical coherence tomography images.

In 21% of the women, the cardiac MRI showed an inflammatory condition known as myocarditis or another reason for heart dysfunction unrelated to artery blockage or blood clotting.

These are alternate diagnoses to heart attack and show the women did not have a heart attack in the first place at all.

For the remaining 16% of the women, both the OCT and MRI scans were normal, and the cause of the heart attack was not found.

These findings demonstrate that even if the angiogram does not show substantial artery blockage when women have symptoms and blood test findings consistent with a heart attack, it is likely a true heart attack and not heart inflammation.

Additional imaging tests can get to the root of the problem and help health care professionals make an accurate heart attack diagnosis for women and to ensure they receive timely treatment.

One author of the study is Harmony R. Reynolds, M.D.

The study was presented at the American Heart Association’s Scientific Sessions 2020.

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