[The intramyocardial coronary artery and the muscular bridge. The physiopathological and surgical considerations in a clinical case].

Muscular bridging of the coronary artery affects both the vessel wall structure and the local blood flow. The vessel wall underneath the muscular bridge is usually thin and free from degenerative atherosclerotic changes. A coronary stenosis caused by a short muscular bridge is considered critical when greater than 75%, but these dynamic obstructions are often asymptomatic because of the diastolic coronary flow. A long intramyocardial course may instead affect blood flow before a critical stenosis has been reached. Spasm and late changes in diastolic compliance of the mural coronary artery play a definite role in the development of ischemia. The case of a young patient with a fully intramuscular left anterior descending artery and repeated episodes of effort spasm is presented, and etiology, features and surgical treatment are discussed.