Prevalence of Myocardial Bridging in Patients With Myocardial Infarction and Nonobstructed Coronary Arteries

Mechanisms of acute myocardial infarction and nonobstructed coronary arteries (MINOCA) are incompletely understood. Myocardial bridging (MB) is usually considered a benign congenital variant, but serious complications have been reported. MB has also been proposed as a cause of takotsubo syndrome (TS). We aimed to examine whether MB was more frequent in patients with MINOCA or TS than in age- and gender-matched controls and to compare the MB detection rates of coronary computed tomography angiography (CTA) and invasive coronary angiography (ICA). Patients with MINOCA (n = 57) and age- and gender-matched controls (n = 58), aged 45 to 70 were enrolled. Myocarditis was excluded by cardiovascular magnetic resonance imaging. Patients with TS (n = 15) were considered as a subgroup and therefore not excluded. Patients with MINOCA underwent ICA and all study participants underwent coronary CTA. All examinations were reviewed with focus on MB. Among 57 MINOCA patients, 15 MINOCA patients with TS and 58 controls, MB was demonstrated in 28 patients (49%), 8 patients (53%), and 26 patients (45%), respectively. There were no statistically significant differences regarding the prevalence of MB or the type, location, length, or thickness of MB. There was a statistically significant difference (p <0.01) between the detection rates of coronary CTA and ICA that demonstrated MB in 54 subjects (47%) and 13 subjects (23%), respectively. In conclusion, MB was frequent with a similar prevalence in patients with MINOCA, patients with TS and controls. This suggests that there is no causal link between MB and MINOCA or TS. Furthermore, coronary CTA detects MB at a significantly higher rate than ICA.