Myocardial bridge: a bridge to atherosclerosis

Area of Science:

• Cardiology
• Congenital Heart Disease
• Coronary Artery Disease

Background:

• Myocardial bridge (MB) is a congenital anomaly where coronary artery segments tunnel through heart muscle, causing systolic narrowing.
• While often benign, MB can precipitate severe complications including myocardial infarction and sudden cardiac death.

Purpose of the Study:

• To investigate the demographic, clinical, and angiographic characteristics of patients diagnosed with myocardial bridge.
• To compare patients with MB alone versus those with MB and co-existing coronary artery disease.

Main Methods:

• Retrospective analysis of 71 patients with MB identified via coronary angiography (1999-2003).
• Patients were divided into Group A (MB without atherosclerotic lesions) and Group B (MB with coronary artery disease).
• Comparison of demographic, clinical, and angiographic data between the two groups.

Main Results:

• Group A patients were younger (mean age 47 vs 55 years) and presented more with stable angina (70% vs 35%).
• Group B patients had a higher frequency of multiple coronary artery disease risk factors (55% vs 30%) and acute coronary syndrome (65% vs 30%).
• Mean bridging percentage was significantly higher in Group B (70% vs 43%), with atherosclerotic lesions often occurring proximally to the MB.

Conclusions:

• Myocardial bridge should be considered in young patients with angina, especially those without multiple coronary artery disease risk factors.
• MB may play a role in initiating or accelerating atherosclerosis, particularly in the proximal coronary segments.
• Superimposed atherosclerosis on MB increases the risk of acute coronary syndrome.