A clinically useful coding system for normal coronary artery anatomy.

Cine coronary arteriograms of 121 patients with normal coronary arteriograms with and without associated valvular or myocardial disease were reviewed to describe normal coronary artery anatomy and the distribution of potentially graftable vessels. Coronary arterio grams were divided into right, mixed, and left interior emphasis systems, depending upon the blood supply to the inferior surface of the left ventricle. Whether a coronary artery at its origin was less than 50%, between 50-70% of the left anterior descending coronary artery (LAD) at its origin was described in a simple lettering and numbering code to allow easy comparison. The diameter of the LAD at its origin averaged 4.2 mm. All vessels greater than 70% of the LAD were clearly graftable. The frequency (in percent) with which that vessel was greater than 70% of the LAD in right, mixed, and left systems, respectively, was as follows: right coronary artery 100. 100. 0. LAD 100. 100. 100. intermediate artery 8.7 12.5 33.3 obtuse marginal artery 53.7 43.7 44.4 atrioventricular groove artery 0. 56.2 100. diagonal branch of the LAD 15. 6.3 11.1. This simple method of classification is recommended to provide more accurate comparison in published series and to assist the coronary arteriographer in his interpretations.