Cardiac magnetic resonance in MINOCA patients: a non-tertiary hospital experience

Abstract

Abstract Background Cardiac magnetic resonance (CMR) is a key tool in the diagnostic process of myocardial infarction with non-obstructive coronary arteries (MINOCA), impacting patient management and prognosis. Its use in non-tertiary hospitals is often constrained mainly by accessibility. Thus, the aim of this study was thoroughly evaluate CMR application in this context to optimize the process. Methods 136 MINOCA patients who were admitted to our hospital between 2016 and January 2024 were analyzed. Each MINOCA patient was reviewed by experts to align with the diagnosis criteria outlined in the 2020 ESC Guidelines and the American Heart Association position paper, which recommended CMR for MINOCA patient’s evaluation. To assess the factors associated with normal-CMR, a logistic regression analysis was performed. In a first step, some factors were detected, showing a trend in the association. In a second step, a backward elimination procedure was used, excluding factors with p>0.1. Results CMR was performed in 65 MINOCA patients (48% of the cohort), with a mean age of 59±15 years old, 35 of them were males (54% of total patients). During the follow-up, there were 4 deaths (6%) and 4 readmissions (6%). Out of the total 65 patients, the CMR diagnosis was myocardial infarction (MI) in 14 (21.5%) and myocarditis in 16 (24.6%), and was normal in 35 (53.9%). Therefore, CMR provided diagnostic information in 46% of the cases. It was noted that a normal CMR was associated with female gender, (OR 2.7, 95% CI 0.96-7.34, p=0.057), hypertension (OR 2.25, 95% CI 0.81-6.22, p=0.11), absence of segmental abnormalities in echocardiography (OR 0.14, 95% CI 0.035-0566, p=0.06) and lower high-sensitivity Troponin T (OR 0.79, 95% CI: 0.66-0.95, p=0.001). In the second step, only segmental abnormalities (OR 0.2, 95%CI 0.04-1.09, p=0.063) and troponin (OR 0.31, 95%CI 0.10-0.99, p=0.048) remained included. Additionally, the Youden Index was determined to obtain the threshold for troponin, resulting a value of 606 nG/mL, area under ROC curve (AUC) = 0.784 (figure). Conclusions - CMR was performed in 48% of the MINOCA patients, reflecting the limitation for its use in routine clinical practice. Furthermore, it was useful in 46% of those patients. - The main factors associated with normal CMR were absence of segmental echocardiography abnormalities and reduced troponin levels. - A troponin cutoff point of 606 ng/mL identified patients with a normal CMR (AUC=0.784).Figure 1.CMR in MINOCA patientsFigure 2.Area under ROC curve = 0.784