Coronary calcium score and CT angiography in myocardial infarction with nonobstructive coronary arteries

Background In clinical practice, intravascular imaging to identify an exact diagnosis in patients presenting with myocardial infarction with nonobstructive coronary arteries (MINOCA) is often omitted. This limits the possibility to target treatment and secondary prevention. Purpose To evaluate the added diagnostic value of coronary calcium score (CaS) and coronary computed tomography angiography (CCTA) in MINOCA patients. Methods We performed coronary CaS and CCTA in 72 patients (mean age 60 ± 14 years, 71% women) hospitalized and diagnosed with MINOCA. Quantitative coronary plaque analysis assessing segment involvement score (SIS), total and low-attenuating plaque volume (<130 Hounsfield Units) was determined by a semiautomatic analysis software. Patients were stratified by normal or abnormal findings by cardiac magnetic resonance imaging (cMRI). Receiver Operator Characteristic (ROC) Curve analysis was performed to compare the diagnostic accuracy of coronary CaS and CCTA in detecting MINOCA patients with abnormalities on cMRI. Results In the study population, 68% had abnormal finding by cMRI and there were no sex differences. The proportion of patients >55 years of age tended to be higher (78 vs 57%, p=0,067), ST-elevation in ECG was more prevalent (27 vs. 4%, p=0.027) and median troponin levels were higher (382 [519] vs. 72 [289] ng/L, p<0.01), compared to patients with normal cMRI. The prevalence of hypertension, diabetes, hypercholesterolemia, obesity and smoking did not differ between groups (all p=ns). Coronary CaS, total and low-attenuation coronary plaque volume did not differ between groups (all p=ns). In ROC Curve analysis, troponin T level identified patients with abnormal findings by cMRI (AUC 0.83 [0.71-0.95], p<0.001). Total plaque volume did not reach statistical significance (AUC 0.59 [0.43-0.75], p=0.254), while coronary CaS and SIS were insignificant (Figure). Conclusions In patients with MINOCA, a higher total plaque volume by CCTA increased the likelihood of abnormalities by cMRI, but did not reach statistical significance. Coronary CaS could not distinguish between patients with abnormal and normal findings by cMRI. Whether advanced plaque analysis by CCTA adds to the diagnostic workup in MINOCA needs to be explored in larger trials.ROC-curve results