Morphometric and topographic study of coronary ostia.

OBJECTIVE To investigate the morphometric and topographic aspects of coronary ostia, correlating them with the aortic leaflets. METHODS Fifty-one hearts with the great vessels attached were analyzed in this study. The ascending aorta was transversally sectioned 1 cm above the commissures of the aortic leaflets. The right and left coronary ostia were analyzed, as were the distances from these ostia to the bottom of the aortic sinuses and to the commissures of the aortic leaflets. RESULTS The left coronary ostium was located below the intercommissural line in 42% of cases, above that line in 40% of cases, and at the level of that line in 18% of cases. The mean distance from the left coronary ostium to the bottom of the corresponding sinus was 12.6 +/- 2.61 mm. The right coronary ostium was located below the intercommissural line in 60% of cases, above that line in 28% of cases, and at the level of that line in 12% of cases. The mean distance from the right coronary ostium to the bottom of the corresponding aortic sinus was 13.2 +/- 2.64 mm. The mean diameters of the left and right coronary ostia were 4.75 +/- 0.93 mm and 3.46 +/- 0.94 mm, respectively. The mean diameters of the juxtamural portion of the left and right coronary arteries were 3.75 +/- 0.79 mm and 2.9 +/- 0.73 mm, respectively. In one case, both ostia were located in the left coronary sinus. CONCLUSION The left coronary ostium may be located either above or below the intercommissural line. The right coronary ostium is predominantly located below the intercommissural line. The coronary ostia have reduced diameters as compared with the juxtamural diameters of their respective coronary arteries.