Clinical Significance of Isolated Coronary Bridges

Myocardial bridging of a coronary artery has been noted in 0.5% to 1.6% of arteriograms but the clinical significance is controversial. We reviewed retrospectively 761 consecutive coronary arteriograms performed in the Chinese PLA General Hospital from 1986 to 1996. Myocardial bridging of a coronary artery was noted in 12 cases (1.5%), located exclusively in the left anterior descending coronary artery and isolated without fixed coronary artery stenosis. The bridges ranged in length from 10 to 50mm (mean 24 mm) and were classified as grade 1 (8% of cases), grade 2 (25%) and grade 3 (67%). All patients were hospitalized because of angina. Eight (67%) of the 12 patients suffered from anterioapical dyskinesia including 2 who had acute myocardial infarction with a left ventricular aneurysm. Three patients (25%) with a small posterior descending coronary artery died. In our view, when there is a hyperdominant left anterior descending coronary artery with a small posterior descending artery and a myocardial bridge, the patient appears to be in jeopardy and myocardial bridging can no longer be considered a benign coronary anomaly, especially when there is grade 3 narrowing of the left anterior descending coronary artery during systole.