Coronary atherosclerosis in Nigeria.

The relative rarity of ischaemic heart disease in the negro is well recognized, but there are very few morphological studies on the quantitative or qualitative aspects of the disease. Of 8,ooo necropsies carried out in the University College Hospital, Ibadan, over a io-year period, there were IO Nigerians with proven myocardial infarcts. Of these, 4 were on the basis of coronary embolism from endomyocardial fibrosis or bacterial endocarditis. Planimetric assessment of Sudan-stained coronary arteries obtained from 279 hearts from consecutive unselected necropsies of Nigerians over the age of IO years was carried out. Seventy-one per cent had no demonstrable atherosclerotic lesion, while in the remaining 29 per cent, the right coronary artery was slightly more affected than the left descending or circumflex arteries. The average percentage of intimal surface involvements of right and left coronary arteries was 23 and 2I, respectively. Fibrous plaques or complicated lesions were infrequent. Coronary thrombi were not seen, but there was a patient who had left-sided endomyocardial fibrosis with myocardial infarction due to coronary embolism. The severity of atherosclerosis increased with age. Though fatty streaking was not uncommon, particularly in early life, the factors that appear to protect the African, including the Nigerian, from advanced stages of coronary atherosclerosis and ischaemic heart disease are poorly understood, but factors such as exercise, diet influenced by the socio-economic class, and fibrinolytic activity are probably significant.