Extra imaging reveals cause of MINOCA in women

Multi-modality imaging with optical coherence tomography (OCT) and cardiac magnetic resonance (CMR) identified an underlying cause in 84.5% of women with myocardial infarction with non-obstructive coronary arteries (MINOCA), according to findings from the HARP-MINOCA study. Identification of the aetiology of MINOCA is feasible and could guide medical therapy for secondary prevention, according to the authors [1].

Prof. Harmony Reynolds (New York University Grossman School of Medicine, USA) presented the results of the HARP-MINOCA study (NCT02905357), designed to identify the cause of MINOCA. Accounting for up to 10% of MI, MINOCA is 3 times more prevalent in women than men and is overrepresented in women of colour, Prof. Reynolds explained. HARP-MINOCA was a prospective, multicentre, international, diagnostic observational study that included 301 female patients with a clinical diagnosis of MI. In this cohort, 170 had MINOCA, of whom 147 underwent OCT; 116 of these 147 patients also underwent CMR. Mean age was 60 years, 50% were non-white and non-Hispanic, and 45% had hypertension.

OCT identified a definite or possible culprit lesion in 67 of 147 women (46.2%; 95% CI 38.0–54.7). Multivariable analysis revealed that culprit was associated with age, abnormal angiography per site, and diabetes, but not with troponin or angiographic stenosis severity. CMR was abnormal in 86 of 116 women (74.1%; 95% CI 65.0–81.6); there was an ischaemic pattern in 62 (53.4%) and a non-ischaemic pattern in 24 (20.7%). Multivariable analysis showed abnormal CMR to be associated with higher peak troponin, creatinine, and diastolic blood pressure, but not with OCT culprit lesion or angiographic stenosis severity. Among the 116 women who underwent both OCT and CMR, a putative cause of MINOCA could be identified in 98 (84.5%; 95% CI 76.3–90.3%). Of them, 74 (64%) had MI, 17 (15%) myocarditis, 4 (3%) Takotsubo syndrome, and 3 (3%) non-ischaemic cardiomyopathies. For the remaining 18 women (16%), both the OCT and MRI scans were normal, and the cause of the MI remained elusive.

“OCT and CMR provide useful information, independently as well as in combination,” Prof. Reynolds summarised the findings. “CMR findings correlated well with OCT culprit lesions, demonstrating that non-obstructive culprit lesions are a frequent cause of MINOCA. Coronary artery spasm or thromboembolism likely caused MI/regional ischaemic injury in cases without OCT culprit. Mechanisms of MINOCA in women were often similar to mechanisms of MI-CAD: atherothrombosis with possible contribution or coronary artery spasm.”

These findings demonstrate that even if the angiogram does not show substantial artery blockage, women with symptoms and blood test findings consistent with a heart attack likely do have a heart attack and not heart inflammation, Prof. Reynolds concluded. “Additional imaging tests can get to the root of the problem and help healthcare professionals make an accurate heart attack diagnosis for women and to help ensure these patients receive timely treatment.”

1. 
   
   1. Reynolds HR, et al. Coronary OCT and Cardiac MRI to Determine Underlying Causes of Minoca in Women. LBS.03, AHA Scientific Sessions 2020, 13–17 Nov.
   2. Reynolds HR, et al. Circulation 2020, Nov. 14. Doi: 10.1161/CIRCULATIONAHA.120.052008

Posted on 18 February, 202123 April, 2024