The clinical anatomy of the conal artery.

Coronary arteries have been extensively described and recognized by gross anatomic studies. However, in the clinical setting, the recognition of the conal artery is essential during coronary angiography, as well as certain congenital heart conditions such as tetralogy of Fallot. In order to provide a complete anatomic and physiologic correlation of the actual incidence and distribution of the conal artery we examined 300 formalin fixed hearts with gross dissections and 300 coronary angiograms. The conal artery was identified in all hearts examined and five main patterns were recognized. In Type A (193, 32.1%), the conal artery arose as a branch of the right coronary artery (RCA); in Type B (96, 16%), the conal artery arose from the common coronary ostium with the RCA; in Type C (242, 40.3%), the conal artery took origin from the right aortic sinus as an independent artery; in Type D (48, 8%), multiple conal arteries were present and arose from the RCA as separate branches (32, 66.6%), from a common ostium with the RCA (8, 16.6%) or from the aortic sinus (8, 16.6%); in Type E (22, 3.6%), the conal artery arose as a branch of the right ventricular branch (17, 2.8%) or acute marginal artery (5, 0.8%). The relative prevalence of the five patterns as well as the morphology and the topography of the conal artery varied significantly with the degree of coronary luminal stenosis (as observed during angiography) and also with the degree of hypertrophied ventricular wall (as observed during gross dissections).