Combined Imaging Approach Identifies Cause of Heart Attack without Coronary Blockage

Patients who present with myocardial infarction but show no obstructive coronary disease often leave without a definitive diagnosis. That uncertainty complicates in-hospital decision-making and post-discharge therapy. A newly introduced dual-imaging strategy aims to resolve the etiology in these cases. Researchers now report finding showing that pairing two complementary cardiac imaging tests can determine the cause in most affected patients.

The approach combines coronary optical coherence tomography (OCT) with cardiac magnetic resonance imaging (MRI). OCT uses a thin intravascular catheter to generate high‑resolution images of the coronary artery wall, detecting plaque disruption or thrombus that may be missed on angiography. Cardiac MRI visualizes myocardial injury patterns to differentiate ischemic damage from inflammation, stress cardiomyopathy, or other nonischemic processes.

In the Heart Attack Research Program (HARP), an international, prospective study across 28 sites in the United States, Canada, and the United Kingdom, investigators enrolled 336 patients with myocardial infarction with non‑obstructive coronary arteries (MINOCA). The median age was 58 years, including 270 women and 66 men. Using both modalities together, clinicians identified an underlying cause in 79% of participants.

Most patients (59%) had a typical ischemic mechanism related to reduced perfusion from plaque pathology, vasospasm, or clotting, while 20% (67 patients) had conditions that mimic infarction, including myocarditis, takotsubo syndrome, or other cardiomyopathies. Diagnostic yield was higher with the combined protocol than with either test alone. Clinical features, biomarker levels, and initial studies did not reliably predict which patients would benefit from one modality over the other, and once MINOCA occurred, underlying causes did not differ significantly by sex.

The findings reinforce guideline recommendations for additional imaging in MINOCA and underscore limitations of standard angiography, which cannot depict intramural plaque pathology or subtle myocardial injury. The results were presented as featured clinical research at the American College of Cardiology’s 2026 Annual Scientific Session and published in Circulation, expanding prior work reported in 2021 that evaluated the same imaging methods in a smaller, all‑female cohort.

“When arteries are not badly blocked, it can be unclear what caused the event. What we show is that in most cases, we can find the underlying explanation, and most often it is a true heart attack. Our results support the need to do specialized imaging in all patients with MINOCA, because we could not reliably predict who will have specific imaging findings,” said Harmony R. Reynolds, MD, director of the Cardiovascular Clinical Research Center, Leon H. Charney Division of Cardiology, NYU Langone Health.

“We had hoped to be able to tailor testing to individual patients. Instead, we found that comprehensive imaging is often necessary to get the full answer,” added Dr. Reynolds.