Sex Differences in MINOCA
Sex Differences in Myocardial Infarction with Non-Obstructive Coronary Arteries
University Hospitals Bristol and Weston NHS Foundation Trust
Duration of Study in the UK
0 years, 2 months, 31 days
Coronary heart disease is the leading cause of death worldwide and was responsible for 200,000 hospital visits and 66,000 deaths in 2018 in the United Kingdom. However around 6% of patients who come to hospital with a heart attack are found to no blockages in their heart arteries. The majority of these patients have an alternative diagnosis (e.g. heart failure, infections, heart rhythm problems) but in the absence of another specific diagnosis these patients are deemed to have had a myocardial infarction (heart attack) with non-obstructive coronary arteries (MINOCA).
Cardiac magnetic resonance imaging (CMR) is a detailed MRI scan of the heart and is proving to be a very valuable test in this cohort. CMR scans can give a diagnosis in up to 74% of patients. The most frequent diagnoses were missed heart attacks (25%), inflammation of the heart muscle (myocarditis) (25%) and heart muscle conditions (cardiomyopathy)(25%), with 26% having a ‘normal’ CMR.
There are clear sex differences in outcomes for patients presenting with heart attacks. Being male is a known risk factor for a heart attack but females have a significantly worse outcome following a heart attack. Women are on average 9 years older than men at the time of their first heart attack and they are consistently underdiagnosed and undertreated compared with men. The percentage of females with MINOCA varies substantially, even between large studies (49%- 64%) demonstrating the uncertainty in defining this cohort. MINOCA is now known to have significant mortality associated with it, around 4.7-5.7% at 12 months but how mortality varies by sex has not been clarified.