Stenotic lesions and the bifurcation angle of coronary arteries in the young.

To determine the genesis of the high incidence of stenotic lesions of the left anterior descending artery (LAD) in the young, we have investigated the anatomical characteristics of coronary arteries in the following 3 groups; young (less than or equal to 40 yr) myocardial infarction (MI) patients with LAD lesions, young (less than or equal to 40 yr) patients without coronary stenosis and aged (greater than or equal to 60 yr) MI patients. The angle between the left main coronary artery (LMT) and the LAD in the young MI patient group (146.7 +/- 7.4 degrees) was significantly wider than those of the young normal (126.0 +/- 13.4 degrees) or the aged MI patient groups (127.1 +/- 18.6 degrees) (p less than 0.01, p less than 0.02, respectively). The angle between the LMT and the left circumflex artery (LCX), and the angle between the LAD and the LCX were not significantly different among the 3 groups. The LMT length in the young MI patient group was 18.3 +/- 4.7 mm, which was not significantly longer than those of the young normal (12.7 +/- 6.9 mm) or the aged patient groups (14.8 +/- 6.0 mm). The internal diameter ratio of the LAD and LCX was also not significantly different among the 3 groups. These results suggest that the angle between the LMT and LAD was significantly wider in young MI patients, and should be regarded as an inherited characteristic influencing the development of coronary atherosclerosis of the LAD, particularly in young MI patients.