Prevalence and clinical presentation of myocardial bridge on the basis of the National Polish Percutaneous Interventions Registry and the Classification of Rare Cardiovascular Diseases.

BACKGROUND A myocardial bridge (MB) is defined as a congenital anomaly, in which a segment of an epicardial coronary artery takes an intramuscular course. AIMS The aim of the study was to evaluate the prevalence of MB in coronary arteries among patients who were diagnosed using coronary angiography. METHODS Data were obtained from the National Polish Percutaneous Interventions Registry for patients hospitalized between January 1, 2014, and December 31, 2016, in invasive cardiology departments in Poland and divided into groups with and without MB. RESULTS The study included 298 558 patients. The non‑MB group comprised 296 133 patients (99.19%; women, 38.01%), while the MB group included 2425 patients (0.81%; women, 39.98%). The most frequent location of MB was the left anterior descending artery (n = 2355; 97.11% of patients). The MB group less often had diabetes (14.68% vs 21.63%), previous stroke (1.61% vs 2.96%), previous myocardial infarction (10.97% vs 21.97%), kidney disease (2.8% vs 5.04%), previous coronary artery bypass graft (1.03% vs 5.64%), previous percutaneous coronary intervention (13.20% vs 25.86%) than the non‑MB group (P <0.0001). The incidence of acute coronary syndromes was lower in the MB group (P <0.0001), while smoking was more common (18.76% vs 16.87%, P <0.01). CONCLUSIONS Patients with MB were younger and had fewer comorbidities and risk factors for atherosclerosis than patients without MB. The condition was more common among patients with stable coronary artery disease. Smoking and female sex appeared to be associated with a more clinically symptomatic presentation of MB.