Multimodality Imaging Clarifies Causes of MINOCA in Men and Women

A large international study highlights the value of combining advanced imaging techniques to determine the underlying causes of myocardial infarction with non-obstructive coronary arteries (MINOCA), a condition that has long posed diagnostic challenges.

In findings published in Circulation, researchers from the HARP Research Group analyzed data from 754 patients enrolled across 28 sites in the United States, Canada, and the United Kingdom. Of these, 389 patients were diagnosed with MINOCA, and most underwent multimodality imaging with coronary optical coherence tomography (OCT) and cardiac magnetic resonance (CMR).

MINOCA encompasses a range of mechanisms, including true ischemic injury and non-ischemic conditions that mimic heart attack. “Imaging is recommended to identify MINOCA etiologies, but it remains unclear which patients are most likely to have abnormal findings,” the authors noted.

The study found that combining OCT and CMR substantially improved diagnostic clarity. Among patients who completed both tests, investigators identified a cause of the clinical presentation in 79% of cases. Specifically, 59% had an ischemic cause of MINOCA, while 20% had a non-ischemic condition mimicking myocardial infarction.

Each modality contributed unique diagnostic value. OCT identified a culprit lesion in 45% of patients, while CMR detected abnormalities in 63%. Notably, OCT revealed lesions even in 27% of patients with otherwise normal angiograms, underscoring the limitations of standard imaging alone.

CMR findings showed an ischemic pattern in 40% of patients and a non-ischemic pattern in 23%, with similar results between women and men. Overall, “no sex differences in imaging results were detected,” the authors reported.

The study also examined predictors of abnormal imaging. Factors such as age, abnormal angiography, and the number of vessels imaged were associated with OCT findings, while peak troponin levels and timing of imaging influenced CMR results. However, clinical predictors were limited in their ability to reliably identify which patients would have abnormal imaging.

“The combination of multi-vessel coronary OCT and CMR… confirmed MI in 59% and identified an alternate cause (MINOCA mimic) in 20%,” the researchers concluded.

The findings support broader use of multimodality imaging in patients with suspected MINOCA, regardless of sex, to improve diagnostic accuracy and guide management.