Value of magnetocardiography in chronic coronary disease detection: results of multicenter trial

Abstract

Abstract Background Diagnostic management of patients with chest pain remains a clinical challenge. Magnetocardiography (MCG) is non-invasive evaluation of the magnetic field of the heart that is produced by the electric activity of the myocardium. Previous studies have clearly demonstrated the potential of MCG in coronary artery disease (CAD) detection. The objective of this multicenter trial is the investigation of value of MCG in diagnosis of mild and severe coronary artery disease using novel approach of magnetocardiographic current density vectors (CDV) maps evaluation. Methods This clinical trial was conducted in three GCP accredited institutions under the leadership of a General Hospital in China. The trials were designed for paired experiments with multi-center blind interpretation. Coronary angiography and coronary flow reserve fraction were used as a “gold standard”. In total 133 persons (mean age 59±3,1 years), divided into 3 groups, were examined. The first group (61 subjects) was identified for patients with severe myocardial ischemia and met the criteria for revascularization: degree of coronary artery stenosis is ≥80% or coronary blood flow reserve score ≤0,8. The second group (13 subjects) is patients whose myocardial ischemia is confirmed but has not yet reached the criteria for revascularization: coronary artery stenosis is between 50% and 80%, coronary blood flow reserve score >0,8. The third group (59 subjects) is whom the “gold standard” confirmed that there is no coronary artery disease. This group is called the negative control group. The MCG examination was performed using a 7-channel MCG system located in an unshielded room. Magnetocardiography recordings were taken from 36 positions at rest Based on the magnetic field distribution, set of subsequent current vectors maps were reconstructed with equidistant time step (10 ms) within the ST-T interval. Each of these maps was classified into two categories: normal map or pathological map. This classification is based on the analysis of the of the largest current density vectors direction and dipole or non-dipole structure of the map. Then, portion of pathological CDV maps within the ST-T interval was defined. Based of this portion, each MCG examination was was assigned to one of 3 groups: mild CAD, severe CAD or no CAD. Results The coincidence rate of each group was as follows: coincidence rate of severe CAD – 85,45%, coincidence rate of mild CAD – 77,78%, coincidence rate of control group was 87,10%. Sensitivity 93,75% and specificity 87,10% were achieved, PPS was 88,24%, NPV 93,10%. In terms of likelhood ratio results were as follows: a positive likelhood ratio of 7.27, negative likelhood ratio – 0.07. Conclusion MCG-examination seems to be a reliable method in the diagnosis of chronic severe and mild CAD. Further large-scale studies needed to confirm these findings. Funding Acknowledgement Type of funding sources: None.