Elevation of markers of myocardial damage, magnetic resonance matters?
Authors: Santos Gonzalez B , Morante Perea C , Gadella Fernandez A , Enriquez Puga A , Fernandez Zapardiel S , Cespedes Mas M , Moreu Burgos J , Rodriguez Padial L 
Published: July 2021

Abstract

Funding Acknowledgements
Type of funding sources: None. Main funding source(s): No conflicts

Introduction
Elevation of cardiac biomarkers represents injury to myocardial cells, but such increases can arise in a great variety of situations with multiple pathophysiological mechanisms. Their management in routine clinical practice is not standardized. Cardiac magnetic resonance (CMR) is a first-line modality for the assessment of the etiology of myocardial injured, with special interest in Myocardial infarction (MI) with non-obstructive coronary arteries (MINOCA).

Purpuse
The objective of our study is to know the use of cardiac resonance in our center for those patients who are admitted with elevated markers of myocardial damage and to assess their diagnostic accuracy.

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. Statistical analysis was done with the SPSS 23 statistical program.

Results
174 patients with troponin I elevation were included in the study. CMR was performed in 103 patients (59.2%) with a median of 4.7 ± 3.1 days from the admission. The mean age of the patients with CMR was 48.8 ± 19.4 years versus 67.3 ± 14.2 years without CMR. 58% of the total sample were men. Only 31.1% of the women underwent CMR. The mean troponin I elevation was 8.6 ng / mL in patients with CMR versus 3.7 ng/mL in patients with no CMR (p &lt; 0.02).
The main indication for cardiac resonance was MINOCA in 60 patients (58.3%), followed suspected myocarditis in 39 patients (37.9%). 67 patients (38.5%) had CMR and coronary angiography done. 36 patients only had CMR study (20.7%) and 71 patients only coronary angiography (40.8%). 13 patients (12.6%) had a systolic function of the left ventricle less than 50% by RMC. The most frequent location of late enhancement was the epicardial (45.6%).
CRM was diagnostic in 84.4%: acute infarction was diagnosed in 8.7%, acute myocarditis in 50.5%, Takotsubo syndrome in 19.4%, cardiomyopathy in 4.9% and normal in 8.7%. In 7.8% the diagnosis was not reached. In patients without CRM, the most frequent diagnosis was acute infarction (59.2%). Five cardiac and non-cardiac deaths were recorded. Four of them in the no-CMR group.

Conclusions
In our study we confirmed the high diagnostic power of the resonance. However, there are still a significant number of patients with troponin elevation without an accurate diagnosis. Compared with non-CMR patients, those with CMR were younger, had a higher prevalence of the male gender, and higher troponin I levels. The diagnostic most frecuent was acute miocarditis. In most cases, the diagnosis of acute infarction is not being supported by resonance. Therefore, this "new pathology" remains a challenge for cardiologists.