Cardiologists and cardiovascular researchers are proposing that MINOCA be redefined as myocardial injury with non-obstructive coronary arteries, arguing that the current terminology does not adequately reflect its role as a “working diagnosis”.
The proposal, outlined in an article in the European Heart Journal [link here], aims to encourage clinicians to avoid prematurely assuming a diagnosis of MI, the article’s corresponding author Dr Chiara Bucciarelli-Ducci told the limbus.
Dr Chiara Bucciarelli-Ducci. Source: Royal Brompton
“The issue to date is the acronym MINOCA is using I for infarction but this is misleading as we don’t know if the patient has an infarction. In fact, most commonly these patients don’t have an infarction but have myocarditis,” she added.
The use of the MINOCA acronym to represent MI with non-obstructed coronary arteries has alternated over time, and across guidelines from a working diagnosis to a final one, she noted, adding that the need for greater consistency was one of the catalysts for the article.
Although the 2023 European Society of Cardiology (ESC) Guidelines for the management of acute coronary syndrome [link here] suggest MINOCA be seen as a working diagnosis, the I for infarction “prematurely” assigns the diagnosis of infarction before physicians carry out invasive and non-invasive tests necessary to confirm it.
“Cardiac MRI is already indicated in class IB to further assess patients presenting with MINOCA to understand if the final diagnosis is indeed infarction or acute myocarditis or Takotsubo syndrome (the 3 most common diagnosis),” said Dr Bucciarelli-Ducci, a consultant cardiologist at Royal Brompton & Harefield Hospitals, Guys and St Thomas NHS Foundation Trust, and CEO of the Society for Cardiovascular MRI.
While a majority of patients in the UK with suspected MI will receive cardiac MRI, its use is more variable elsewhere in Europe and in the US, she said, with data remaining sparse.
Patients presenting with the working diagnosis of MINOCA often have in common symptoms suggesting ischaemic causes such as acute pain presentation and/or abnormal ECG, transient troponin rise and non-obstructive epicardial coronary arteries, Dr Bucciarelli-Ducci and her colleagues point out.
These symptoms can, nevertheless, result in a range of final diagnoses.
“This new definition of MINOCA, replacing the “I” for infarction with the “I” for injury, better reflects the working diagnosis nature of this terminology, while also emphasising the need for further invasive and non-invasive testing to identify the final diagnosis, which can be epicardial, microvascular, myocardial and non-cardiac,” the authors said.
They cited a recent meta-analysis indicating that only 22% of patients presenting with MINOCA had an epicardial coronary cause of MI, while about two-thirds had a non-epicardial coronary, microvascular (e.g. Takotsubo syndrome), or myocardial cause of MINOCA (e.g. acute myocarditis, and other cardiomyopathies).
Moreover, reaching an MI diagnosis precipitously, meanwhile, is misleading for both doctors and patients, and can have wider implications in areas such as insurance and mortgages, that frequently use health information, Dr Bucciarelli-Ducci noted.