MINOCA, what can we do to enhance its handling?
Authors: Santos Gonzalez B , Morante Perea C , Rodriguez Padial L , Gigante Miravalles E , De Cabo Porras C 
Published: April 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) have a prevalence of 5 to 6% of acute myocardial infarction (AMI). The management of MINOCA in routine clinical practice is not standardized. There are patients who are admitted with elevated markers of myocardial damage, without meeting the MINOCA criteria. Diagnostic and therapeutic approaches vary between patients and hospitals and that has an impact on the prognosis.
Objetives
The objective of our study is to determine the handling differences of the patients depending if it is used "MINOCA working diagnosis" or not and the usefulness of cardiac resonance (CMR).

Methods
Retrospective observational cohort study conducted in patients with elevated markers of myocardial damage between January 2017 and December 2019. Patients with stable coronary artery disease, unstable angina pectoris, a history of revascularization, type 4/5 MI and patients with documented arrhythmic were excluded. CMR was performed on an Avanto Siemens 1.5T.

Results
174 patients with troponin I elevation with no exclusion criteria, were included in the study. 118 patients were included as MINOCA working diagnosis and 56 were included in the non-MINOCA group. The mean age of patients included in MINOCA was 63.6 ± 15,4 while the mean age of the non-MINOCA patients was 41.0 ± 19 (P &lt; 0,05). There were more woman on MINOCA group (52,5% vs 19,6%, p &lt; 0,05).
Patients with MINOCA had lower peak troponin values (5,1 ± 9,3 vs 9,7 ± 10,9, p &lt; 0,05) and more cardiovascular risk factors. The percentages of atrial fibrillation were also higher in this group (19,5%, p &lt; 0,05). 96,4% of non-MINOCA (p &lt; 0,05).
The most frequent symptoms in the MINOCA group was typical angina (73.7%) and atypical angina (15.3%), however, in the non-MINOCA was pericarditis (37.5 %) and atypical chest pain (17.9%) (p &lt;0.05). The reason for requesting RMC in the non-MINOCA group is mainly myocarditis (37,5%), followed by cardiorrespiratory arrest (3,8%) (p &lt; 0,05).
In the MINOCA group, CMR was performed in 41,5%: acute infarction was diagnosed in 14,3%, acute myocarditis in 36,7%, Takotsubo syndrome in 26,5%, cardiomyopathy in 10,2% and normal in 6,1%. In 6,1% the diagnosis was not reached. Nevertheless, in the other group, CMR was perfomed in 96,4%. The main diagnostic was acute myocarditis (61,8%). 65% of patients underwent both RMC and coronary angiography.
Definitive diagnosis at the time of discharge was acute infarction (40,8%), Takotsubo syndrome (24,6%) and acute myocarditis (15,3%) in MINOCA patients. In the other group, acute myocarditis (60,7%) and Takotsubo syndrome (12,5%).

Conclusions
In our study, we confirm that the use of MINOCA as a "working diagnosis" allows us a global and standardized handling of this patient profile, and consequently, there was a diagnostic trend towards requiring more RMC. The most patients were included in non-MINOCA group because a high clinical suspicion of acute myocarditis.