Does the myocardial bridge protect the coronary from atherosclerosis? A comparison between the branches of the dual-left anterior descending coronary artery type 3: an autopsy study.

Objective: The best way to prove the protective role of myocardial bridges in the development of atherosclerotic changes in portions of the coronary beneath the bridge is to compare the morphological changes of the walls of the coronaries with and without a myocardial bridge, in those who have a so called 'dual left anterior descending coronary artery (dual LAD) type 3'.

Methods: A prospective autopsy study was performed over a 12-year period and approximately 3000-3500 hearts were examined, in order to establish the presence of a dual LAD type 3.

Results: A total of 10 such cases were observed and further analysed. The group entirely consisted of men, who were of an average age of 62.1 ± 20.4, and whose age ranged from 24 to 86. It could be assumed that both the short and long LAD artery were exposed quite equally to all major non-modifiable and major potentially controllable factors for atherosclerosis. Consequently, the degree of severity of atherosclerosis in the short and long dual LAD artery, as well as the difference between degrees, depends only on the presence of a myocardial bridge. This difference increased with the age of the deceased (Spearman's correlation coefficient ρ = 0.695, P = 0.026).

Conclusion: If the observed subject was older, the atherosclerotic changes were more prominent and severe in the short rather than in the long dual LAD. The protective role of the myocardial bridge has been established more accurately than has been found in other studies; however, this didn't mean that atherosclerosis was absent in intramyocardial course of coronary artery, but it was less prominent.