What is coronary artery bridging?

Coronary artery abnormality is a common disease among modern people. It can be divided into various types, such as coronary artery myocardial bridge. What is coronary artery myocardial bridge? Studies have shown that this is related to the superficial myocardium covering the coronary arteries, which affects the normal development of the coronary arteries. In short, coronary artery bridging is a cardiovascular disease. So what kind of disease is coronary artery bridging? I hope that through the detailed explanation in this article, you will have a more comprehensive understanding of this disease.

Coronary myocardial bridge is a congenital abnormality of the coronary artery development. The main coronary artery and its branches usually run in the subepicardial fat on the surface of the heart or in the deep surface of the epicardium. However, during the development of the coronary arteries, a segment of the coronary artery or its branches may be covered by the superficial myocardium and run inside the myocardium. The coronary artery segment covered by the myocardium is called the parietal coronary artery, and the myocardium covering the coronary artery is called the myocardial bridge (MB). Myocardial bridging may be related to local factors in the onset of coronary heart disease and may also cause myocardial ischemia. When the heart contracts, the section of the coronary artery covered by the myocardial bridge is compressed, resulting in systolic stenosis. When the heart relaxes, the compression on the coronary artery is relieved and the coronary artery stenosis is also relieved.

Causes

The cause of the disease is that the intramyocardial segment of the coronary artery, especially the intramyocardial segment of the left anterior descending branch, may be squeezed during contraction, and symptoms of myocardial ischemia usually appear after middle age.

Clinical manifestations

The clinical manifestations of myocardial bridge are closely related to the classification.

1. Superficial type

Because the myocardial bridge is thin and short, it has little effect on coronary blood flow, and most patients have no symptoms of myocardial ischemia and corresponding electrocardiogram changes.

2. Depth type

Because the myocardial bridge is thick and long, it has a great impact on coronary blood flow, causing angina pectoris and ST-T changes of myocardial ischemia on the electrocardiogram. If myocardial bridge is complicated by coronary atherosclerosis and secondary thrombosis or plaque detachment, clinical symptoms of myocardial infarction and corresponding electrocardiogram changes may appear. Myocardial ischemia is more likely to occur when myocardial bridge is combined with tachyarrhythmia.

Most myocardial bridges do not cause clinical symptoms. The symptoms that occur mainly include: angina pectoris, acute myocardial infarction, atrioventricular conduction block, heart failure, and sudden death.

diagnosis

In addition to clinical symptoms and corresponding electrocardiogram changes, the diagnosis of myocardial bridge still depends on coronary angiography, intracoronary Doppler and ultrasound examinations. The superficial type is difficult to diagnose because it is asymptomatic or has mild symptoms. Even coronary angiography can only detect deep myocardial bridges.

treat

The principle of treatment for myocardial bridge is to relieve the compression of the coronary artery below the myocardial bridge. Drug or surgical treatment can be used for patients with symptomatic myocardial bridge and atherosclerotic plaques at the myocardial bridge.

1. Medication

Angina pectoris caused by systolic coronary artery compression is effective against beta-blockers, calcium antagonists (such as verapamil and diltiazem), and antiplatelet drugs.

2. Surgery

Those who are difficult to control with drug therapy should undergo surgical treatment. There are two surgical procedures: myocardial resection and coronary artery bypass grafting.

(1) Myocardial bridge resection is suitable for superficial types. Under normal temperature general anesthesia, the myocardial bridge is found and removed to completely relieve the pressure on the coronary artery and restore its distal blood flow. Simple myocardial resection is rarely performed simultaneously with coronary artery bypass grafting.

(2) Coronary artery bypass grafting is suitable for patients with deep or combined arteriosclerotic stenosis. Coronary artery bypass grafting can be performed under normothermic general anesthesia, normothermic extracorporeal circulation, or hypothermic extracorporeal circulation. The graft material can be autologous great saphenous vein or internal mammary artery.