Prevalence, Anatomic-Topographic Features and Clinical Significance of Myocardial Bridges: a Retrospective Study

Aim. To analyze the prevalence and anatomic-topographic features of myocardial bridges (MBs) and evaluate their role in the development of cardiovascular complications.
Design. А retrospective study.
Materials and methods. The study was conducted in two stages. In the first stage, to assess the prevalence and anatomic-topographic features of MBs, was retrospectively analyzed a registry of 883 coronary computed tomographic angiography (CCTA) results performed at the S.M. Kirov Military Medical Academy from 2011 to 2021. From the remaining 811 results after the initial review, 117 CCTA with MBs were selected and subjected to further detailed study. In 6 cases the CCTA was supplemented with stress-CT myocardial perfusion. In the second stage, a retrospective analysis of medical histories of 20 patients with MBs who were treated at the S.M. Kirov Military Medical Academy from 2017 to 2021 was performed for assessment the clinical significance of MBs and their role in the development of cardiovascular complications.
Results. According to CCTA MBs were visualized in 14.4% of cases, in the left anterior descending artery (LAD) they were diagnosed in 84.6% of them with predominant localization in the middle segment — 94.9%. The mean length of the MBs in the LAD was 23 [17; 31] mm, depth — 1 [1; 2] mm. Atherosclerotic lesion according to classification of Coronary Artery Disease Reporting and Data System (CAD-RADS) of the LAD was detected in 58.6% of cases, of which in the proximal segment — 84.5%. According to stress-CT myocardial perfusion in asymptomatic patients, hypoperfusion was detected in 3 (50%) cases in the segments of the left ventricle, the blood supply of which comes from the LAD and its branches. Among 20 patients with dyslipidemia was detected in 80% of patients with MBs, stable angina was diagnosed in 5 (25%) cases, unstable angina and myocardial infarction — 3 (15%) patients in each cases. The assessment of the lipid spectrum revealed the elevations of total cholesterol to 5.47 ± 1.25 mmol/l and low-density lipoprotein to 3.52 ± 1.04 mmol/l, other fractions remained within normal values. In addition, various heart arrhythmias and conduction disorders were detected by 24-hour electrocardiography monitoring in patients with MBs, including supraventricular and ventricular extrasystoles, supraventricular and ventricular tachycardia, A-V blockade, atrial fibrillation and flutter and pauses greater than 2.5 seconds.
Conclusion. The study confirmed the predominant character of MBs localization in the LAD and its middle segment. In addition, frequent atherosclerotic lesion of proximal segments of LAD by CAD-RADS classification was detected. The presence of association of MBs with symptoms of myocardial ischemia, dyslipidemia, as well as various arrhythmias requires searching of new approaches to early visualization of MBs, especially in the group of asymptomatic patients, in order to diagnose the pathology on time and prevent cardiovascular complications associated with it.

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