Effectiveness of magnetocardiography to identify patients in need of coronary artery revascularization: a cross-sectional study

Background: Patients with angina-like symptoms need invasive or non-invasive angiography to determine whether revascularization is necessary. For patients in need of revascularization, undergoing coronary computed tomography angiography (CCTA) may delay the treatment of revascularization and increase exposure to contrast agents and radiation. The aim of this cross-sectional study was to accessed the effectiveness of magnetocardiography (MCG) to identify patients who should undergo coronary revascularization. Methods: A total of 203 patients who were suffering from angina-like symptoms and underwent percutaneous coronary angiography (PCA) between July 27, 2015 and April 10, 2017 at the 8th Medical Center of Chinese PLA General Hospital, were enrolled in this cross-sectional study. In all patients, 12-lead electrocardiography (ECG) and MCG test were performed before PCA. For each subject. The value at every single sampling point was extracted from T wave of each MCG channel in time sequence. Pearson's correlation coefficients were calculated for each two T-waves. A binary logistic regression diagnosis model of these coefficients was established to identify patients in need of revascularization. Results: Ten pairings of coefficients were entered into diagnostic regression model as covariates. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.747 (95% CI: 0.680-0.815), and the asymptotic P value was less than 0.001. At the cut-off value of 0.55, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 72.9%, 65.9%, 74.8%, 63.6% and 69.9%, and the positive and negative post-test probabilities were 65.9% and 25.7%. The accuracy, sensitivity, specificity, PPV and NPV for 12-lead ECG were 67.0%, 62.7%, 63.5%, 70.5% and 55.1%, respectively. However, when those acute myocardial infarction (AMI) patients were ruled out from both groups, the MCG model had an accuracy of 68.2%, a sensitivity of 70.1%, a specificity of 66.3%, a PPV of 68.5% and an NPV of 67.9%. But, the accuracy, sensitivity, specificity, PPV and NPV for 12-lead ECG were 60.0%, 55.2%, 65.1%, 62.3% and 58.1%, respectively. Conclusions: Patients suffering from angina-like symptoms, with a logistic regression model value over 0.55, should be recommended for PCA.