The size of human coronary arteries depending on the physiological and pathological growth of the heart the age, the size of the supplying areas and the degree of coronary sclerosis

It seems that the postmortem diameters of coronary arteries after filling under physiological pressure correspond with the maximal intravital diameters, and the view that coronary arteries of hearts with infarctions are smaller before the onset of atherosclerotic lesions is not supported.

Abstract

In 300 human hearts of all age groups (pre-natal to senescence) postmortem angiographs were performed under a pressure of 100 mmHg. The largest diameters of the three coronary arteries (i.e. the right coronary artery, the left descending and the left circumflex branch) were determined. In our material we did not find ectatic coronary arteries in old age in the absence of atherosclerosis. We suggest that as a rule the larger diameters of the dissected coronary arteries in older hearts may be a postmortem phenomenon, due to the decreased elasticity of the vascular walls, which manifests itself as a progressive loss of retraction. In female hearts the cross-sectional areas of the coronary arteries were a little smaller than in male hearts of same age groups (statistically not significant). In postmortem hearts of normal weights the diameters of the coronary arteries exceeded intravital measurements of other authors by nearly 15%, but there is good correlation between our postmortem findings and intravital measurements after application of nitroglycerin. It seems that the postmortem diameters of coronary arteries after filling under physiological pressure correspond with the maximal intravital diameters. In our material we found that even in hearts beyond the critical weight coronary arteries are able to grow. Because of the limited number of hearts with an excessive weight and healthy coronary arteries we cannot decide whether under pathological conditions the growth of the coronary arteries corresponds harmonically with the growth of the myocardium. There were large variations in coronary artery diameters during the physiological and pathological growth of the heart. If only the sum of the right coronary artery and the common stem of the left main coronary artery were considered the variations were smaller. On the average the largest diameters of coronary arteries with atherosclerosis were smaller than the diameters of healthy coronary arteries. We found a good correlation between the thickening of the intima of sclerotic vessels and the decrease in their diameters. Therefore we cannot support the view that coronary arteries of hearts with infarctions are smaller before the onset of atherosclerotic lesions. Furthermore we compared the cross-sectional areas of the coronary arteries with their supplying areas. We found the best correlation for the right coronary artery. During late fetal development and childhood there was a nearly linear correlation between the increase in the sum of cross-sectional areas of the three coronary arteries and the weight of the heart. During later physiological and pathological growth of the hearts there was a progressively slower increase of the cross-sectional areas. These differences were not present when the diameter of the healthy coronary arteries was compared with the "diameter of the ventricular muscle mass" (calculated as the cube root of the weight of the ventricular part = WVP). The closest correlation of all was found between these two linear parameters.