High-sensitivity troponin I peak in MINOCA: a useful tool in the right clinical context?

Introduction Myocardial infarction with nonobstructive coronary arteries (MINOCA) is defined by a clinical diagnosis of Myocardial Infarction (MI) and exclusion of significant epicardial stenosis on coronary angiography. In the presence of clinical suspicion, the decision to perform coronary angiography is based on biomarker levels. Purpose To evaluate if high-sensitivity troponin-I (hsTnI) in patients with myocardial infarction and elevated cardiac biomarkers has a good discriminative power to predict MINOCA. Methods A retrospective analysis of consecutive AMI patients who underwent coronary angiography admitted to the cardiology department from November 2021 to October 2022 was conducted. We analysed demographic and cardiovascular risk factors, initial and peak hs-TnI, index-hospitalization data and evaluated the presence of significant coronary artery stenosis at coronary angiography. Univariable and multivariable analysis was performed to obtain the Odds Ratio (OR, 95% CI, p-value) for significant coronary artery disease (CAD). ROC curve and area under the curve (AUC) were obtained to determine the discriminative power of peak hsTnI as predictor of a positive coronary angiography. Optimal cut-point value was obtained (Youden index) and patients were divided according to this value. Results A total of 375 patients (72.0% males) with a mean age of 66.4 ± 12.3 years were submitted to coronary angiography. MINOCA was present in 18 patients (4.8%). When comparing patients with or without significant CAD at coronary angiography, the groups differed in relation to male sex (p=0.033), regional wall motion abnormalities at admission (p=0.039) and peak hsTnI (p=0.001). Optimal cut-point value for predicting the presence of significant coronary artery stenosis at coronary angiography was a peak hsTnI of 7010 pg/mL (AUC 0.724, p-value 0.001, 95% CI 0.593-0.855). The characteristics of the two groups are described in Table 1. In the hsTnI >7010 group, mean age was 65.6 ± 12.9 years and 61% were male; 58% had a diagnosis of hypertension, 55% had dyslipidemia, 55% had type 2 diabetes mellitus and 66% were smokers. The two groups differed significantly in the presence of dyslipidemia (p= 0.033), type 2 Diabetes mellitus (p=0.033), and presence of regional wall motion abnormalities at admission (p<0.001) (see table). After adjustment, peak hsTnI >7010 pg/mL was the only independent predictor of significant CAD (OR 4.732, 95% CI 1.469-15.243, p-value 0.009). Conclusion In the right clinical context where there is high suspicion for MINOCA, decision to perform and/or timing of coronary angiography could be based on peak hsTnI values. In this population, patients with hsTnI < 7010 pg/mL without established cardiovascular risk factors, namely dyslipidemia and type 2 diabetes mellitus and without region wall motion abnormalities at admission, are more likely to have MINOCA.