Background: To investigate the association between unrecognized myocardial infarction (UMI) assessed with cardiac magnetic resonance (CMR) and coronary artery calcium (CAC) and cardiovascular risk prediction scores in asymptomatic Asian subjects.
Materials and methods: Total 872 asymptomatic subjects without prior cardiovascular event (male:female, 817:55; age, 53.88 ± 5.91) who underwent both CMR and CAC scoring CT were included. UMI were accessed and framingham risk score (FRS) and ASCVD (atherosclerotic cardiovascular disease) risk score by ACC/AHA were calculated.
Results: Late gadolinium enhancement indicating UMI was noted in 23 of 872 subjects (2.64%), but only three of them showed ECG abnormality (13.04%). Subjects with UMI showed higher CAC scores, FRS, and ASCVD scores than those without UMI (p < .001, p = .011 and p = .024, respectively). The prevalence of UMI differed significantly according to the CAC scores as follows: 1% in CAC = 0 (4/403), 1% in 1 ≤ CAC <100 (2/293), 6.1% in 100 ≤ CAC < 400 (7/114) and 14.5% in CAC ≥ 400 (9/62), respectively (p < .001). Receiver operating characteristics (ROC) analysis by using CAC score demonstrated an area under the curve (AUC) of 0.816 (95% confidence interval (CI), 0.780-0.848; p < .0001) for predicting UMI, which is superior to FRS [AUC, 0.712; 95% CI, 0.671-0.751; p = .009] and ASCVD risk score [AUC, 0.689; 95% CI, 0.648-0.729; p = .036].
Conclusion: The prevalence of UMI increases with increasing burden of CAC and FRS. CAC score is a good discriminator for UMI, superior to FRS and ASCVD score, in asymptomatic population.