Henry C. Mcgill

Coronary Calcification Relationship to Clinically Significant Coronary Lesions and Race, Sex, and Topographic Distribution

Measurements of the per cent of the surface with calcified lesions have been made for the three main coronary arteries from 1,242 consecutive necropsies of whites and Negroes between the ages of 30 to 69 years. Calcified lesions were most prevalent and most extensive in the left anterior descending branch and occurred with greatest frequency at 2 to 3 cm. from the orifice. Whites had greater involvement than Negroes and males had greater involvement than females. Prevalence and extent of calcification have been compared in four cause-of-death or disease categories; cases dying of coronary heart disease had greater involvement than the other three groups. The prevalence of ischemic myocardial lesions, complicated coronary lesions, or stenotic lesions was greater for cases with calcified lesions, and this prevalence increases with increase in extent of calcified lesions. The significance of the presence of coronary calcified lesions for the diagnosis of advanced coronary atherosclerosis is greatest for younger individuals.

Arterial Lesions in the Kenya Baboon

One hundred sixty-three baboons (Papio doguera were sacrificed and autopsied immediately after being trapped in their natural habitat in Kenya, British East Africa. Approximately three-fourths of the 67 adults had some degree of aortic intimal lipid deposition, as indicated by gross Sudan IV staining, and a few animals had extensive fatty streaks. These fatty streaks were more frequent with advancing age, but there was no sex difference. Electron microscopy disclosed most of the intimal lipid droplets to be intracellular. Fibrous plaques were infrequent and had a variable but usually low lipid content. One elderly male had fibrous plaques with hemorrhage into their bases. Histologic sections of the coronary arteries showed many small musculo-elastic intimal plaques in which lipid could only rarely be demonstrated. The aortic intimal lipid deposits cannot be attributed to the consumption of excessive animal fat or to hypercholesterolemia. These results indicate that the baboon, like man, is highly susceptible to arterial intimal lipid deposition and that it promises to be an excellent animal for the experimental investigation of atherosclerosis. They further more caution that adequate controls be used in all experimental work involving arterial lesions in primates.

Atherosclerosis in the Bantu

The aortic lesions of atherosclerosis in Bantu, aged 1 to 40 years, have been studied in 241 autopsied cases from Durban, South Africa. The findings are compared with those from a similar study of white and Negro cases in New Orleans, La. The relationship of incidence and quantitative extent of aortic fatty streaks and fibrous plaques to race, environment, blood lipid levels, coagulation factors, and clinical manifestations of atherosclerosis is discussed.

REPORT OF COMMITTEE ON GRADING LESIONS, COUNCIL ON ARTERIOSCLEROSIS, AMERICAN HEART ASSOCIATION Grading Human Atherosclerotic Lesions Using a Panel of Photographs

The American Heart Association9s Committee on Grading Lesions of the Council on Arteriosclerosis has devised a method of grading the severity of atherosclerosis in human coronary arteries and aortas. The method uses two series of color photographs of arteries arranged in increasing severity of atherosclerosis. The Committee tested the method for inter-observer reproducibility by exhibiting the panel at two national scientific conventions and inviting visitors to grade a set of arteries with the panel. The test demonstrated a reasonable degree of inter-observer reproducibility despite a wide range of experience and disciplinary background. Inter-observer variability decreases with increasing experience in working with atherosclerotic lesions. Training graders who participate in a study may reduce inter-observer bias. For populations with predominantly less or predominantly more atherosclerosis, the investigator should construct special panels with different ranges of severity. The Committee revised the panel in the light of the results of the two exhibits and the comments of users in a field trial. The revised panel provides seven possible scores for each coronary artery and for each aorta. This panel provides a relatively simple and speedy quantitative method of comparing autopsy data on atherosclerosis among many kinds of studies and has the added advantages of facilitating comparisons between different geographic locations and different times.

Diet and serum cholesterol levels in baboons

Abstract The baboon is capable of responding to dietary cholesterol with a moderate increase of serum cholesterol within one year. Marked individual variation in this response occurs with animals on identical diets. The level of dietary cholesterol is the only dietary variable (of those investigated) with a major effect on changes in serum cholesterol after 12 months on diet. Fat blends, one made up predominatly of corn oil and another composed principally of beef tallow, butter oil, and hydrogenated vegetable fats, appear to have no main effect on changes in serum cholesterol after 12 months on diet, but there is interaction between dietary cholesterol and type of fat. Dietary protein levels of 8 and 20% of calories appear to have no major effects on changes in serum cholesterol levels.

Colloid Goiter and Atherosclerosis

The thyroid glands from 453 patients 20 to 79 years of age from the New Orleans area were classified according to the presence of colloid goiter, and the coronary arteries and aortas from these same patients were independently graded for atherosclerotic lesions. There was no correlation between colloid goiter and atherosclerosis; nor was there any difference in the percentages of deaths from atherosclerosis in goitrous patients as compared to nongoitrous patients. Because goiter may differ in its functional manifestations from one geographic area to another, and because one group of investigators in Finland has reported a strong association between the two diseases, similar studies should be conducted in other areas. The subject of increased severity of atherosclerosis in human hypothyroidism was reviewed, and it was concluded that the presently recorded data are not adequate to establish a positive relationship.

Deposition of Lipid in Calf Aorta Maintained in Vitro

Morphologic and histochemical observations on the isolated perfused calf aorta maintained in vitro provide evidence that the aortas remain viable during perfusion. The appearance of lipid in the inner layers of the aortic wall corresponds to the previously reported biosynthesis of lipid by the aortic wall. There is a lag period of 24 to 48 hours between the chemical and morphologic appearance of lipid.

REPORT OF COMMITEE ON GRADING LESIONS, COUNCIL ON ARTERIOSCLEROSIS, AMERICAN HEART ASSOCIATION Grading Stenosis in the Right Coronary Artery

The American Heart Associations Committee on Grading Lesions of the Council on Arteriosclerosis has devised a method of grading the severity of atherosclerosis in human coronary arteries and aortas. The method uses two series of color photographs of arteries arranged in increasing severity of atherosclerosis. The Committee tested the method for inter-observer reproducibility by exhibiting the panel at two national scientific conventions and inviting visitors to grade a set of arteries with the panel. The test demonstrated a reasonable degree of inter-observer reproducibility despite a wide range of experience and disciplinary background. Inter-observer variability decreases with increasing experience in working with atherosclerotic lesions. Training graders who participate in a study may reduce inter-observer bias. For populations with predominantly less or predominantly more atherosclerosis, the investigator should construct special panels with different ranges of severity. The Committee revised the pan...